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International Journal of Ad Hoc and Ubiquitous Computing


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International Journal of Ad Hoc and Ubiquitous Computing (96 papers in press)


Regular Issues


  • Differentiation Forwarding with Hotspot   Order a copy of this article
    by Peiyan Yuan, Huadong Ma 
    Abstract: Social-based forwarding is one of the most interesting and significant topics in opportunistic networks. Whereas, this scheme brings us a lot of opportunities and poses new challenges as well, due to the unique features such as the intermittently connected environment and the multi-properties pertaining to each node (e.g., the centrality and similarity). In this paper, we focus on the following questions 1) Can we effectively evaluate node centrality and similarity in dynamic environment? 2) Can we quickly and adaptively differentiate them only based on nodes' local observations? 3) How does our method improve opportunistic forwarding? We propose DifferHot, a three-phase architecture for not only evaluating effectively but also adjusting adaptively the weight for centrality and similarity in social opportunistic scenarios. With the great advantage of this differentiated forwarding scheme, DifferHot helps considerably in reducing up to 7 times and 4 times overhead in Prophet and MobySpace respectively, while keeping delivery ratio sufficiently close to that by Epidemic.
    Keywords: Differentiation forwarding; hotspot; centrality; similarity; Opportunistic networks
  • Joint Multipath Rate Control and Scheduling for SVC Streams in Wireless Mesh Networks   Order a copy of this article
    by Mohammad H. Hajiesmaili, Mohammad Sadegh Talebi, Ahmad Khonsari 
    Abstract: In the recent years, there has been a rapid proliferation of video transmission scenarios in wireless mesh networks. Adapting rate of video signal to different QoS scenarios through scalable video coding (SVC) standard is a desirable key feature for multimedia transmission over wireless mesh networks. This paper addresses joint multipath rate control and scheduling for SVC-encoded video transmission over wireless mesh networks. Each SVC stream is associated with a staircase utility function with multiple paths along its source-destination. By employing the conflict graph to represent the wireless link interference, we formulate the problem as one of maximizing the sum of source utilities subject to transport and link layer constraints. The multipath wireless model and staircase nature of utilities yields non-convex and non-differentiable optimization problems. In order to come up with a convex formulation, we adopt multimodal sigmoid approximation and focus on utility-proportional fairness approach. Then, using dual decomposition, we devise a dual-based distributed algorithm for joint multipath rate control and scheduling algorithm in wireless mesh network. Experimental results validate the correctness and effectiveness of our endeavor toward achieving cross-layer optimization for video transmission scenarios in wireless mesh networks.
    Keywords: Wireless Mesh Networks, Scalable Video Coding (SVC), Multipath Rate Control, Scheduling, Cross-Layer Optimization, Convex Optimization.
  • Content-Oriented Learning Recommendation Mechanism in MANETs   Order a copy of this article
    by Lun-Ping Hung, James J. Park, Kuo-Chung Chu, Neil Y. Yen 
    Abstract: In accordance with the needs and preferences of personal learning, a multidimensional mechanism for content-oriented learning is proposed in this work, which aims at providing tailored educational contents to students in an open environment (i.e., wireless environment). This mechanism is implemented in an intelligent tutoring system which primarily consists of three interactive modules for the delivery of relevant contents. The SOM (Self-Organizing Maps) is applied for the analysis of the factors (e.g., individual needs, preferences, and etc.) and as the main process towards the delivery of recommendations and achieve personalization. Results demonstrate that the proposed mechanism give a solution to the issue of information overload, which has existed in wireless learning environments, and enhances students interest and efficiency in distance education. Regarding the issue on information overload, two main contributions are achieved. First, as learning content online is abundant, learners typically lack the knowledge of needed to choose the most suitable learning contents. Second, the main server becomes overloaded when massive amounts of learner requests for multimedia learning content at the same time. Furthermore, by providing learning content tailored to each learner, learners receive personalized services when learning online.
    Keywords: Information overload; Adaptive learning; Intelligent tutoring system (ITS); Self-organizing Map (SOM); MANET (Mobile Ad Hoc Networks)
  • Cooperative detection of primary user emulation attacks based on channel-tap power in mobile cognitive radio networks   Order a copy of this article
    by Wen-Long Chin, Trong Nghia Le, Chun-Lin Tseng, Chun-Shen Tsai, Wei-Che Kao, Chun-Wei Kao 
    Abstract: This work proposes a new method for identifying a primary user emulation attack (PUEA) at low signal-to-noise ratios (SNRs) in mobile cognitive radio (CR) networks. Channel-tap power is utilized as a radio-frequency fingerprint to directly detect users via physical (PHY) layer. To improve the detection performance in fading channels, the cooperative detection schemes using the fixed sample size test (FSST) and the sequential probability ratio test (SPRT) are devised. From simulation results, for a mobile CR speed of 70 km/h, SNR = -5 dB, and false alarm probability of 0.03, the FSST using ten cooperative nodes can achieve the detection probability of 0.99, which is increased by 1.94 times that of the single Neyman-Pearson detector. When the SPRT is compared to the FSST, the SPRT only needs less than half of the detection time of the FSST to provide the same detection performance for all SNRs considered.
    Keywords: channel-tap power; CR; cognitive radio; cooperative detection; physical layer detection; PUEAs; primary user emulation attacks.
  • Design and evaluation of a decentralized information service architecture for IEEE 802.21 networks   Order a copy of this article
    by Luis Javier García Villalba, Fabio Buiati, Delfin Ruperez Canas, Daniel Corujo, Rui L Aguiar 
    Abstract: The recent deployment of several wireless access technologies such as Wi-Fi, WIMAX and LTE brings to the mobile user the opportunity to switch from one network to another, in a seamless manner. To accomplish this, the mobile user must be able to discover which types of network connectivity are available. The IEEE 802.21 standard specifies a Media Independent Information Service (MIIS) that provides capabilities for discovering network information existing within a geographical area, to facilitate the handover process. The automation, representation and distribution of mobility information in heterogeneous networks are a big challenge, especially in a multi-operator environment. In this paper, we introduce a novel decentralized mobility information service architecture that improves the mobile user experience and ensures scalability for large system deployments. Additionally, a meticulous evaluation using the NS-2 network simulator is presented. The results demonstrate that our research outperforms the standard MIIS approaching in terms of query delay, user
    Keywords: Mobility, IEEE 802.21, Heterogeneous Networks, Media Independent Handover, Decentralized.
  • SSARP: A Sound Speed Adaptive Routing Protocol for Large-scale Underwater Acoustic Sensor Networks   Order a copy of this article
    by Yen-Da Chen, Chun-Chih Li, Chan-Ying Lien, Ching-Hung Wang, Kuei-Ping Shih 
    Abstract: In this paper, an important property of acoustic signal that the speed of acoustic signal varies with water depth has been considered to explore a new routing protocol in UASNs. It implies that the shortest end-to-end delay path may not be the shortest path directly from the source to the sink. Based on this property, a per-hop based routing protocol, named sound speed adaptive routing protocol (SSARP), is proposed. SSARP takes the acoustic speed in different water depth into consideration. SSARP can find a path with a short end-to-end delay to transmit the data. The simulation results also verify that SSARP actually reduces the end-to-end delay and outperforms other routing protocols in terms of end-to-end delay.
    Keywords: sound speed; underwater sensor networks; acoustic communication; routing
  • An efficient negative acknowledgement-based transport protocol in 802.11 media streaming   Order a copy of this article
    by Suherman Suherman, Suherman Suherman, Marwan Al-Akaidi, Marwan Al-Akaidi 
    Abstract: This paper considers the use of negative acknowledgement (NACK)-based transport layer protocols in video transmission over 802.11 networks. A study of various transport layer protocols that utilize NACK to acknowledge packet loss is presented. A new NACK packet scheduling is introduced to enhance the retransmission performance. A mathematical model and analysis are presented to compare protocol performances in relation to delay and packet loss. The analysis is then confirmed through simulations using the ns-2 simulator. Further, this paper presents the outcomes of an experiment to verify the analysis and simulation results. The results show that reducing the number of NACK packets within one video frame could reduce effective loss rate and delay.
    Keywords: Computer networks; transport layer protocol; negative acknowledgement; inter-frame scheduling.
  • Efficient Algorithms for Sensor Detachment in WMSNs   Order a copy of this article
    by Li-Ling Hung 
    Abstract: Target Coverage is an important issue in Wireless Sensor Networks (WSNs). This work copes with the target coverage problem which dispatches a set of mobile sensors to targets efficiently. Given a set of disconnected targets with different Quality of Monitoring (QoM) and a set of mobile sensors which are distributed randomly in the networks, this paper develops two efficient algorithms for dispatching mobile sensors to the targets such that the QoM of each target is satisfied. Performance study reveals that the proposed mechanisms outperform known mechanisms in terms of the satisfied QoMs of all targets and the movement cost of all mobile sensors as well as the life time of the Wireless Mobile Sensor Networks (WMSNs).
    Keywords: Target Coverage; Wireless Mobile Sensor Networks(WMSNs); Quality of Monitoring(QoM)
  • A Comparative Study of Packet Combining Based Error Recovery Schemes for Wireless Networks   Order a copy of this article
    by Sheng-Shih Wang, Pei-Chun Lee, Kan-Yen Lin, Tzu-Chang Yeh 
    Abstract: To provide reliable communications in wireless environments, two fundamental error control mechanisms, automatic repeat request (ARQ) and forward error correction (FEC) are proposed. However, the ARQ mechanism may suffer frequent retransmissions and the FEC mechanism incurs bandwidth overhead. To reduce the number of retransmissions and support efficient correction, previous studies have proposed numerous packet combining based error recovery schemes. This study investigates the recovery performance of three packet combining based error recovery schemes, including the extended ARQ (EARQ), the merge strategy in the simple packet combining (SPaC-M), and the destination packet (DPC) schemes through the mathematical analysis and simulations. Results present that the EARQ outperforms the SPaC-M and the DPC in recovery speed in case of a large packet length and a high bit error rate. However, the EARQ is not suggested if the space overhead is the major consideration.
    Keywords: packet combining; error recovery; automatic repeat request; forward error correction
  • Four-ary Query Tree Splitting with Parallel Responses for RFID Tag Anti-collision   Order a copy of this article
    by Ming-Kuei Yeh, Jehn-Ruey Jiang, Shing-Tsaan Huang 
    Abstract: In an RFID system, tags can be identified by a reader when they are within the interrogation zone of the reader. Collisions occur when tags using backscatter technology report their IDs to the reader at the same carrier frequency simultaneously. The performance of tag identification is degraded by collisions, so it is important to address the tag collision problem. Several anti-collision protocols have been proposed for reducing tag collisions. They can be categorized into two classes: ALOHA-based and tree-based protocols. This paper proposes a 4-ary query tree-based anti-collision protocol, namely the parallel response query tree (PRQT) protocol, to improve the performance of tag identification. In the PRQT protocol, the tags with the ID prefix matching either the readers request bit string or the complementary of the string are arranged to respond in two subcarriers in parallel. The PRQT protocol is analyzed, simulated, and compared with related ones to demonstrate its advantages.
    Keywords: RFID; anti-collision; query tree; tag identification
  • \Design and Implementation of a Transmission Protection Protocol to Improve the Performance of Wireless Sensor Networks in Hybrid Networks   Order a copy of this article
    by Jang-Ping Sheu, Shu-Hsun Wu, Chuang Ma, Wei-Kai Hu 
    Abstract: In hybrid networks, the devices of WLANs and WSNs will interfere with each other when working in a same area because they use the same band, 2.4GHz. With the greater transmission power and more aggressive channel access time resolution, WLANs often affect the communication of WSNs severely. To eliminate this kind of interference effect, we design protection nodes and propose a transmission protection protocol, WTPP, to improve the transmission performances of WSNs in hybrid networks. The protection nodes can emit protection signal periodically to block the traffic of WLANs and permit the transmission of WSNs. We implement WTPP in a hybrid network testbed to prove its feasibility. Comparing with legacy ZigBee, the experimental results show that WTPP can improve the packet delivery ratio of WSNs efficiently under the interference of WLANs. When WSNs work on low duty cycle, the throughput degradation of WLANs is less than 6%.
    Keywords: Hybrid networks, transmission protection, wireless local area networks, wireless sensor networks
  • A General Approach for the Intensive RFID Reader Deployment   Order a copy of this article
    by shijie zhou 
    Abstract: Due to the limited read region of the RFID reader, we usually need to deploy a large number of readers in a certain area. The challenge of the intensive RFID reader deployment lies in that the collision among RFID readers decreases the read rate and speed. In this paper, we propose a general approach to reduce the collision among readers and the number of readers. The basic idea of the approach is to maximize the coverage rate of readers and minimize the overlapping rate of readers, which is known as a NP hard problem. Such an approach contains two parts: grid-based model and PSO-based algorithm. We firstly build a grid-based model to describe both deployment area and read region. In particular, we divide them into small grids, and express grid graphs in a matrix form. Then, we propose a PSO-based (particle swarm optimization) algorithm to optimize the intensive RFID reader deployment. Our simulation results show that the general approach can achieve high coverage rate and low overlapping rate.
    Keywords: RFID reader; deployment; PSO; coverage
  • Touchware: a Software Based Technique for High Resolution Multi-touch Sensing devices   Order a copy of this article
    by Xiaoling Wu 
    Abstract: Finger pointing on touch screens is a very natural way of human computer interaction. However, for many capacitive multi-touch sensing devices, it may suffer from the nature of direct input since the size of human fingers and the lack of sensing precision can make absolute positioning on touch screen difficult, especially multi-touch sensing devices. Even if high resolution/precision multi-touch devices become popular in the market, the cost is high and the positioning algorithm is not a flexible module. In this paper we present Touchware, a software based technique to overcome these limitations with low cost and to provide support for the development of multi-touch applications for rich input modalities. We introduce the maxima based clustering algorithm to detect and distinguish single/multiple touches, weight based geometric center algorithm to calculate a precise interpolated (x, y) coordinate for each finger touch, and first contact based decision with sniper for ghost pattern (symmetric pattern) elimination. We also prove the relationship between the user-defined resolution and the normalized capacitance values. We evaluated the performance and show how the techniques can be successfully used for single touch applications, such as click, scroll, flick, and multi-touch applications such as zoom in/out and rotation.
    Keywords: multi-touch, touch screen, algorithm, absolute positioning, applications
  • A Link-Adapted Fragment and Rate Matching (FaRM) MAC Protocol for Wireless LANs   Order a copy of this article
    by Kuei-Ping Shih, Chien-Min Chou, Chun-Chih Li, Li-Jie Cheng 
    Abstract: The paper proposes a fragment and rate matching (FaRM) MAC protocol for wireless LANs to resist the frequent change of channel quality so as to increase network throughput. In wireless transmissions, channel quality varies with time. The FaRM protocol estimates channel quality by detecting current SNR through frame exchanges. A Finite State Markov Chain (FSMC) is utilized to predict the variation in the channel conditions during the next frame transmission. According to the results obtained from the FSMC, the FaRM protocol enables the sender to dynamically select an appropriate transmission rate as well as an acceptable fragment length to transmit, such that the reliability and time of this transmission can be improved. As a result, the FaRM protocol can not only obtain better network throughput through the selection of the high transmission rate, but it can also increase the successful transmission rate by the determination of a suitable fragment length. Simulation results show that the FaRM protocol has better performance, higher transmission reliability, and lower transmission delay by fragment and rate matching in comparison to the related work.
    Keywords: Finite state Markov chain (FSMC); fragmentation; IEEE 802.11; media access control (MAC); multirate; wireless LANs
  • Defending against Key Exposure in Attribute-based Encryption   Order a copy of this article
    by Jin Li, Xiaofeng Chen, Haibo Tian, Chongzhi Gao 
    Abstract: Since the notion of attribute-based encryption (ABE) was proposed, it has been found a lot of important applications such as fine-grained access control. However, there is no attention paid on how to prevent key exposure in ABE. This problem is first addressed and formulated in this paper. We introduce the notion of key-insulated ABE (KI-ABE) as a solution to the key exposure problem. The definition and security model of KI-ABE is formally proposed. Then, a KI-ABE scheme is presented, which is provably secure under the proposed model. Specifically, the scheme is secure in the remaining time periods against an adversary who compromises the insecure device and obtains secret keys for the periods of its choice. Finally, we show that the scheme also supports user delegation, which is critical when one wants to delegate part of attributes (privileges) to others.
    Keywords: attribute-based encryption; key exposure; delegation
  • Consensus Clustering for Urban Land Use Analysis using Cell Phone Network Data   Order a copy of this article
    by Enrique Frias-Martinez 
    Abstract: Pervasive large-scale infrastructures, such as cell phone networks, have the ability to capture individual digital footprints, and as a result, generate datasets that provide a new vision on human dynamics. In this context, cell phones and cell phone networks, due to its ubiquity, can be considered one of the main sensors of human behavior. The information collected by these networks can be used to understand the dynamics of urban environments with a detail not available up to now. One of the areas that can benefit from this information is urban planning. In this paper, we present a technique for the automatic identification of land uses from the information gathered by a cell-phone network. Our approach first computes the aggregated calling patterns of the antennas and, after that, finds clusters that identify how individuals use each geographic region. Given the inherent diversity of human activities in urban landscapes, we use consensus clustering to identify land uses, characterizing only those geographical areas with well defined behaviors. We present and validate our results using cell phone records and official land use data collected for Madrid.
    Keywords: Urban Mobility; Urban Dynamics; CDR; Land Use; Consensus Clustering.
  • Jamming and Anti-jamming Techniques in Wireless Networks: A Survey   Order a copy of this article
    by Alvin Lim, Kanika Grover, Qing Yang 
    Abstract: Because of the proliferation of wireless technologies, jamming in wireless networks has become a major research problem due to the ease in blocking communication in wireless networks. Jamming attacks are a subset of denial of service (DoS) attacks in which malicious nodes block legitimate communication by causing intentional interference in networks. To better understand this problem, we need to discuss and analyze, in detail, various techniques for jamming and anti-jamming in wireless networks. There are two main aspects of jamming techniques in wireless ad hoc networks: types of jammers and placement of jammers for effective jamming. To address jamming problem, various jamming localization, detection and countermeasure mechanisms are studied. Finally, we describe the open issues in this field, such as energy efficient detection scheme and jammer classification.
    Keywords: Jamming; anti-jamming; wireless networks; classification of jammers; placement of jammers; localizing jammers; detection of jammers; countermeasure for jamming.
  • The design of dynamic access control for hierarchical sensor networks with key-lock-pair mechanism   Order a copy of this article
    by Xi Chen, Yun Liu, Chin-Chen Chang, Changlu Lin 
    Abstract: In recent years, wireless sensor networks have been applied extensively. Since low-power and mobile sensor networks with flat topology demand high efficiency, good scalability, and security, a new structural dynamic access control scheme is needed. In this paper, we explore the task of providing access privileges in hierarchical sensor networks with directed graph and partially-ordered set tools. As the new class of sensors joins or an old one leaves, there will be a huge overhead of calculations on the large-scale network. We present a novel, efficient, and dynamic access control scheme that makes it unnecessary to change all the keys for the Central Authority (CA) and requires only a small amount of computation for each sensor. Specifically, we make use of a key-lock-pair mechanism based on Newtons interpolating polynomial for key management. Extensive analysis showed that our proposed scheme is secure under security models and efficient for both CA and users.
    Keywords: key-lock-pair; dynamic access control; hierarchical sensor network
  • Using Known Vectors to Improve Data Dissemination in Opportunistic Networks   Order a copy of this article
    by Ling-Jyh Chen, Jyh-How Huang, Li-Ping Tung 
    Abstract: An opportunistic network is a type of challenged network in which contacts are intermittent, an end-to-end path rarely exists between the source and the destination, disconnection and reconnection are common occurrences, and link performance is highly variable or extreme. Conventional methods of data dissemination in opportunistic networks rely on a meta-message exchange scheme, called the Summary Vector (SV), to prevent redundant transmission of data bundles that already exist on receivers. We consider that the SV scheme is costly in terms of the data transmission overhead, which is unaffordable in opportunistic networks. Hence, we propose an alternative scheme, called the Known Vector (KV), to improve the efficiency of meta-message exchanges for data transmission in opportunistic networks. Using a comprehensive set of simulations with realistic network scenarios, we demonstrate that the KV scheme can be easily integrated into existing opportunistic network routing protocols (e.g., Epidemic and PRoPHET routing). Moreover, it can reduce the communication overhead significantly, thereby improving energy efficiency for data transmission in opportunistic networks.
    Keywords: DTNs; opportunistic network; DTN routing; Ad Hoc routing.
  • Measuring the similarity of PML documents with RFID-based sensors   Order a copy of this article
    by WANG Zhong-qin, YE Ning, Reza Malekian, ZHAO Ting-ting, WANG Ru-chuan 
    Abstract: The Electronic Product Code (EPC) Network is an important part of the IOT.The Physical Mark-Up Language (PML) is to represent and describe data related to objects in Electronic Product Code (EPC) Network. The PML documents of each component to exchange data in EPC Network system are XML documents based on PML Core schema. For managing theses huge amount of PML documents of tags captured by RFID readers, it is inevitable to develop the high-performance technology, such as compressing the amount of data, filtering and integrating these tag data. For above purpose, one of the effective methods is clustering, which could depend on the structure and semantics of these data. Indeed, the similarity computation, which measures the similarity of the compared PML documents, is the foundation of the clustering method. So in this paper, we propose an approach for measuring the similarity of PML documents based on Bayesian Network of several sensors. With respect to the features of PML, while measuring the similarity, we firstly reduce the redundancy data except information of EPC. On the basis of this, the Bayesian Network model derived from the structure of the PML documents being compared is constructed. And this model has taken into consideration not only the EPC values contained in the PML but also their internal structure. Then the similarity between two PML documents could be deduced. Finally, the simulations evaluate the value range of similarity, timing result and the effectiveness of the similarity measure.
    Keywords: Physical Mark-Up Language; Bayesian Network; Electronic Product Code; RFID.
  • Phase Imperfect Collaborative Event Driven Energy Efficient Protocol   Order a copy of this article
    by Milosav Andelic, Stevan Berber, Akshya Swain 
    Abstract: The present paper proposes a novel Collaborative Event Driven Energy Efficient Protocol (CEDEEP) for single hop event driven Wireless Sensor Networks (WSN) with phase imperfect collaborative communication. CEDEEP takes advantages of spatiotemporal features of event driven WSN and uses collaborative communication to conserve more energy. In this research the effects of imperfectly phase synchronized signals on the performance of CEDEEP for collaborative event driven WSN have been investigated. An analytical model of the network is developed and the effectiveness of CEDEEP is considering in Rayleigh fading and Additive White Gaussian Noise (AWGN) channel. The results of the simulation confirmed CEDEEP efficiency even when imperfect phase synchronization exists between received collaborative signals. Therefore, this research gives strong evidences of CEDEEP ability to ensure high energy efficient operation of phase imperfect collaborative event driven WSN over Rayleigh fading and AWGN channels.
    Keywords: Event driven wireless sensor network, collaborative communication.
  • Multicast Delivery Using Opportunistic Routing in Wireless Mesh Networks   Order a copy of this article
    by Amir Darehshoorzadeh, Llorenç Cerdà-Alabern 
    Abstract: Opportunistic Routing (OR) has been proposed to improve the efficiency of unicast protocols in wireless networks. In OR, in contrast to traditional routing, instead of preselecting a single specific node to be the next-hop forwarder, an ordered set of nodes (referred to as candidates) is selected as the next-hop potential forwarders. In this paper, we investigate how OR can be used to improve multicast delivery. We propose a new multicast routing protocol based on opportunistic routing for wireless mesh networks, named Multicast Opportunistic Routing Protocol (MORP). MORP opportunistically employs a set of forwarders to send a packet toward all destinations. Each forwarder is responsible for sending the packet to a subset of destinations. Based on the candidates that successfully receive the packet in each transmission, MORP builds a tree on the fly. We compare our proposal with two well known ODMRP and ADMR multicast protocols. Our results demonstrate that MORP outperforms ODMRP and ADMR, reducing the number of data transmissions and increasing the delivery ratio.
    Keywords: Opportunistic routing; Multicast; Wireless; Mesh networks.
  • TWIST: A Tree-based Web Service Indication Scheme for Service Tracking in Vehicular Ad-hoc Networks   Order a copy of this article
    by Yu-Hong Lee, Chyi-Ren Dow, Chih-Yu Chueh, Shiow-Fen Hwang 
    Abstract: Because of the progress of modern automobiles, it is possible to use vehicles as sensors to gather information. Although the cost of providing services on a specific node is high in mobile ad hoc networks (MANETs), it is easier to locate a particular node and provide services in vehicular ad hoc networks (VANETs) than in MANETs because vehicles are limited on roads. Public transportation systems are suitable for providing Web services. This study proposes a geo-aware tree-based service-tracking scheme to locate a specific service in a particular area. The virtual backbone is predefined according to the main roads in the city. It consists of geo-grids and is further organized into a tree structure. The tree structure, which is the higher layer of the virtual backbone, can be used to facilitate service location tracking because any grid inside the tree has only one route to the root. Based on footprints from services on the branches of the tree, it is easy to find a specific service and access data of interest in VANETs. The footprints are updated when the service moves from one grid to another, or cleared when the service jumps into another branch of the tree structure. The experimental results indicate that the proposed approach outperforms both AODV and the centralized scheme regarding the tracking success rate and service-tracking time.
    Keywords: Vehicular Ad-hoc Networks, Web Services, Service Tracking, Footprint
  • Principal Component Analysis-based data reduction model for Wireless Sensor Networks   Order a copy of this article
    by Murad Rassam, Anazida Zainal, Mohd Aizaini Maarof 
    Abstract: Wireless Sensor Networks (WSNs) are widely used in monitoring environmental and physical conditions, such as temperature, sound, vibration, humidity, light and voltage. However, the high dimension of sensed data, especially in multivariate sensor applications, increases the power consumption in transmitting this data to the base station and hence shortens the lifetime of sensors. Therefore, efficient data reduction methods are needed to minimize the power consumption in data transmission. Principal Component Analysis (PCA) is a statistical technique used for data reduction by projecting the correlated observations on a set of new coordinates called principal components. The high spatial and temporal correlation of sensor data makes PCA a suitable technique for data reduction in WSNs. In this paper, an efficient PCA-based model for multivariate data reduction in hierarchical WSNs is proposed. The performance of the proposed model was evaluated using a real sensor network deployment dataset collected at Intel Berkeley Research Lab (IBRL). The experimental results show the advantages of the proposed model as it allows 50% reduction rate and 96% data approximation accuracy after reduction. A comparison with Multivariate linear Regression model (MVR) shows that the proposed model is superior in terms of approximation accuracy as the data reconstruction error is always smaller for different testing datasets
    Keywords: Wireless Sensor Networks; Principal Component Analysis; data reduction; multivariate data analysis.
  • Robust Dynamic ID-based Remote User Authentication Scheme Using Smart Cards   Order a copy of this article
    by Xiong Li, Jianwei Niu, Yazhi Liu, Junguo Liao, Wei Liang 
    Abstract: Smart card based password authentication scheme is one of the most simple and efficient method to identify the legitimacy of a user via an insecure channel. In order to protect the user from tracking by the attacker, many dynamic ID-based user authentication schemes have been proposed. Recently, Chen et al. proposed an efficient and secure dynamic ID-based authentication scheme using smart cards. However, we find that Chen et al.'s scheme cannot really protect user's anonymity and forward secrecy. Besides, their scheme is inefficient in the authentication phase and cannot resist stolen smart card attack. In this paper, we propose a robust dynamic ID-based user authentication scheme using smart cards to cover the above weaknesses, the proposed scheme can really protect the user's anonymity and is more secure comparing with other related schemes.
    Keywords: Authentication scheme; Dynamic identity; Smart card; Password
  • Designing for Privacy in Ubiquitous Social Networking   Order a copy of this article
    by Antonio Sapuppo, Joao Figueiras 
    Abstract: Improving human communication during face-to-face meetings is nowadays possible by transferring online social networking benefits to the physical world. This is enabled by the ubiquitous social networking services that became available by means of wirelessly interconnected smart devices, automatically exchanging personal data of the users. The main goal of these services is to facilitate the initialization of relationships between people who do not know each other, but they probably should. Given that sharing of personal information is an intrinsic part of ubiquitous social networking, these services are subject to crucial privacy threats. Inspired by the usability and privacy limitations of existing design solutions, we identify, describe and introduce four drawbacks to be avoided when designing ubiquitous social networking applications. By addressing these drawbacks, services become more functional and more oriented to respecting end users privacy, thus contributing to the long-term success of this technology. Subsequently, we propose the design of a privacy-aware ubiquitous social networking platform, which is engineered both to avoid the four drawbacks and to comply with the existing relevant privacy guidelines. Finally, we present the results of a qualitative analysis, which aims at investigating users perceptions towards the protection of their privacy in relation to the four drawbacks.rn
    Keywords: Privacy; Ubiquitous Computing; Information Disclosure; Social Networking; Design Guidelines.
  • Privacy and Technology Challenges for Ubiquitous Social Networking   Order a copy of this article
    by Antonio Sapuppo, Boon-Chong Seet 
    Abstract: Ubiquitous social networking can be seen as an evolution of ubiquitous computing supporting the social well-being of people in their everyday lives. The vision of ubiquitous social networking focuses on enhancing social interactions among its participants during users physical meetings. This target is leading towards important challenges such as social sensing, enabling social networking and privacy protection. In this paper we firstly investigate the methods and technologies for acquisition of the relevant context for promotion of sociability among inhabitants of ubiquitous social networking environments. Afterwards, we review architectures and techniques for enabling social interactions between participants. Finally, we identify privacy as the major challenge for networking in ubiquitous social networking environments. Consequently, we depict design guidelines and review privacy protection models for facilitating personal information disclosure.
    Keywords: Privacy; Ubiquitous Computing; Information Disclosure; Context awareness; Social Networking; Design Guidelines.
  • Cross-Layer-based Reliable Robust Transmission for Emergency Messages in High Mobility Unreliable VANET Networks   Order a copy of this article
    by Ben-Jye Chang 
    Abstract: To achieve active safe driving and autonomous driverless vehicle have become a key trend in Intelligent Transport Systems (ITS) recently. However, in the high-mobility unreliable Vehicular Ad-hoc NETworks (VANETs), the emergency messages are difficult to disseminate to receivers in time. The efficiency of the active safe driving is thus degraded significantly. The reliable end-to-end transmission protocol suffers from extremely reliable links and high mobility, and hardly provides an accurate congestion window (cwnd) for transmissions. This paper thus proposes a Cross-Layer-based reliable robust Transmission Control Protocol, namely CL-TCP, to forward real-time emergency messages in VANET. To overcome the unstable network topology in VANET, CL-TCP proposes several TCP states: normal, congestion, loss, unstable, frozen and disconnecting, to control TCP cwnd according to the underlying network status of the layer 2 (L2) and the layer 3 (L3) protocols. Additionally, in L2 we propose the Enhanced AODV (EAODV) algorithm to determine the path with the longest path lifetime as the optimal path in L2, and thus increase the path reliability and maximize the throughput. The designed cross-layer messages include: CL_EAODV, CL_ICMP_FB, CL_ICMP_DU, etc. Numerical results demonstrate that CL-TCP outperforms others in goodput, the number of link-breaks, average packet delivery ratio, etc. Furthermore, CL-TCP yields a higher fairness among TCP connections.
    Keywords: Cross-layer, active safe driving, Enhanced AODV, Frozen state, reliable robust transmission, VANET
  • Efficient Traffic Load Reduction Algorithms for Mitigating Query Hotspots for Wireless Sensor Networks   Order a copy of this article
    by Chia-Hsu Kuo, Tzung-Shi Chen, Ying-Hung Lo 
    Abstract: In query-based wireless sensor networks, a hotspot of the designated node may cause the heavy power consumption due to the frequent query request among sensor nodes for specific events. A hotspot also leads to the fluctuation of traffic flow among its neighboring nodes and the unbalanced energy among those neighboring sensor nodes. To mitigate the hotspot phenomenon, a target region with the fluctuation of traffic flow around the hotspot in order to handle the unbalance traffic load is first constructed. In this paper, we propose two efficient traffic load reduction algorithms for mitigating query hotspots for wireless sensor networks. The algorithms solve the hotspot problem with frequent query requests. One is Distance-based Mobile Agent Selection (DMAS). The other is Greedy-based Mobile Agent Selection (GMAS). A sensor node connected to the boundary nodes in the target region, called limb node, shares the heavy traffic load of the hotspot by through of gathering the events to the hotspot and responding the request data to the targeted nodes. In other words, the boundary node equipped with mobile agent is called limb node that moves around the hotspot. By setting up mobile agents (boundary nodes) within a target region around the hotspot, we use DMAS and GMAS to mitigate the hotspot phenomenon. In this paper, we investigate the mobile agent selection problem and conduct the experiment in different environment condition. Experiment results include the comparisons of hotspot rate, the comparisons of total energy consumption, hotspot traffic rate with different RT value, hotspot traffic rate with different query frequency, and the effect of the hotspot overlay avoidance. The results show that both DMAS and GMAS can mitigate the traffic rate of hotspot around 50%, effectively.
    Keywords: Wireless Sensor Network; Hotspot; Mobile Agent; DMAS, GMAS.
  • Performance Evaluation of Beacon Enabled IEEE 802.15.4 Network with Downlink and Uplink Traffic and Limited Retransmission   Order a copy of this article
    by mahshad parsa, Seyed Ahmad Motamedi, Hadi Safdarkhani, Mohsen Maadani 
    Abstract: Nowadays, wireless communication is a developing technology. IEEE 802.15.4 is the commonly used standard in low-data-rate and low-power applications. In real-time communications, quality of service is an important issue where delay parameter plays a crucial role. In this paper, at first a novel Markov model has been proposed for the IEEE 802.15.4 standard considering limited retransmission and both uplink and downlink traffics at the same time. Then based on the developed model and using queuing theory the average transmission delay of a packet is derived. It is shown, using numerical simulations, that the behavior of the proposed model is close to the IEEE 802.15.4 protocol and the average delay derived from mathematical expressions and markov simulations are really close to each other.
    Keywords: IEEE 802.15.4 standard; Markov chain; Mac layer service time; Uplink and Downlink transmission; Packet delay
  • Crowd Location Forecasting at Points of Interest   Order a copy of this article
    by Jorge Alvarez-Lozano, J. Antonio García-Macías, Edgar Chávez 
    Abstract: Predicting the location of a mobile user in the near future can be used for a large number of user-centered ubiquitous applications. This can be extended to crowd-centered applications if a large number of users is included. In this paper we present a spatio-temporal prediction approach to forecast user location in a medium-term period. Our approach is based on the hypothesis that users exhibit a different mobility pattern for each day of the week. Once factored out this weekly pattern, user mobility among points of interest is postulated to be markovian. We trained a hidden Markov model to forecast user mobility and evaluated our approach using a public dataset. The experimental results show that our approach is effective considering a time period of up to seven hours. We obtained an accuracy of up to 81.75 % for a period of 30 minutes, and 66.25 % considering 7 hours.
    Keywords: Data mining; Data sharing; Spatio-temporal crowd location forecasting; User location predictability; User mobility similarity.
  • Selectable Sensing Period Optimization for Energy-Constrained Cognitive Radio Networks   Order a copy of this article
    by Long Zhang, Liusheng Huang, Hongli Xu 
    Abstract: Recently, cognitive radio has been proposed to improve the spectrum resource utilization. In cognitive radio networks, the secondary (or unauthorized) users (SUs) are allowed to sense, detect and utilize the frequency bands that are not currently being used. Once the primary user (PU) is active, the secondary users have to vacate the channel within certain amount of time. Thus, it is a challenging task to find the suitable sensing period for better spectrum utilization. In this paper, we propose a selectable sensing period optimization (SSPO) mechanism. In the algorithm, each secondary user use the different periods for channel detection according to the different channel states. so that we can deal with the tradeoff between spectrum utilization and energy consumption more flexibly. We consider the constraint of interference to PU and the energy consumption to compute the optimal sensing periods. Our simulation results demonstrate that, with the constraint of energy consumption, the SSPO algorithm can gain the spectrum utilization 22.8% more than the previous algorithm. Moreover, with the constraint of spectrum utilization, the SSPO algorithm can save the energy consumption 20.6% more than the previous algorithm.
    Keywords: Cognitive radio networks, Spectrum sensing, Energy constraint, Selectable sensing period
  • Performance Analyses of Minimizing Emergency Message Collisions and Maximizing Network Throughput in IEEE 802.11p VANET Network   Order a copy of this article
    by Ben-Jye Chang, Ying-Hsin Liang, Jiun-Ting Lai 
    Abstract: IEEE 802.11p is proposed as the VANET wireless MAC interface for the transmissions of emergency messages in V2V and V2I Communications. However, in a high mobility VANET, QoS of both the emergency message (EM) and handoff transmissions suffer from high collision probability of the contention-based media access mechanism and high interference exhibiting near the cell-edge that encodes a low coding rate of the Adaptive Modulation and Coding (AMC) scheme. Thus, this paper proposes an efficiency MAC for IEEE 802.11p to solve above critical issues, in which the approach consists of three main mechanisms: 1) the Sigmoid-based CW Decrease (SWD) algorithm,2) the Dynamic Initial CW (DIW) algorithm, and 3) Relay-based partition Collision Domain for Handoffs (RCDH). Note that the CW decrease formulation is determined based on the Sigmoid function. Numerical results demonstate that the analysis results are close to the simulation results, and thus justify the correctness of the mathematical analytical model. In addition, the proposed approach outperforms the compared approaches (including the IEEE 802.11p std.) in EM transmission delay, collision probability, throughput, and MAC frame dropping probability.
    Keywords: IEEE 802.11p, Markov chain model, Contention window, Sigmoid function, VANET
  • Link-Preserving Interference-Minimization Channel Assignment in Multi-Radio Wireless Mesh Networks   Order a copy of this article
    by Li-Hsing Yen, Kuo-Wei Huang 
    Abstract: Using multiple channels with multiple radios per node in a wireless mesh network can potentially improve system capacity. This design requires the appropriate assignments of channels/radios to wireless backhaul links and creates a tradeoff between conflicting constraints and requirements. This study attempts to maximize the number of operative links, where a link is operative if radios at both ends of the link share a common channel (i.e., are link-preserving) and experience sufficiently low co-channel interference. These two criteria are conflicting in nature. A link-centric, channel-first radio resource assignment scheme that considers physical interference model and tight radio constraint is proposed. The proposed approach ensures link preservation and assigns channels to links based on the predicted upper bound and lower bound of the accumulated co-channel interference associated with particular assignments. Simulation results indicate that the proposed algorithm outperformsrnexisting approaches in the number of operative links, particularly when only a few channels, or many radios, are available.
    Keywords: channel allocation; wireless mesh network; interference; multi-radio
  • An Efficient Indexing and Query Mechanism for Ubiquitous IoT Services   Order a copy of this article
    by Chu Du 
    Abstract: Nowadays mobile equipments are used widely and connected to the Internet ubiquitously. Billions of sensing devices are deployed for collecting context information in order to support intelligent and realtime decision support. Besides functionality specification, most devices have spatial and temporal constraints. In this setting, how to organize sensing devices properly and thus to achieve the discovery of devices efficiently with respect to the requirement of certain applications is a challenge. To remedy this issue, this paper proposes a multiple index method to organize sensing devices considering their functionality specifications, spatial and temporal attributes, and develops a query mechanism leveraging this multiple indexes. Experiment results show that this technique is effective and efficient.
    Keywords: Ubiquitous IoT Services; Sensing Devices; Functionality Clustering; Spatial and Temporal Indexes
  • BEST: A Bidirectional Efficiency-Privacy Transferable Authentication Protocol for RFID-Enabled Supply Chain   Order a copy of this article
    by Saiyu Qi, Li Lu, Zhenjiang Li, Mo Li 
    Abstract: Radio Frequency Identification (RFID) technique is gaining increasing popularity in supply chain for product management. By attaching a tag to each product, a reader can employ an authentication protocol to interrogate the tag's information for verification, which facilitates the automatic processing and monitoring of products in many applications. However, most current solutions cannot be directly used as they cannot balance the tradeoff between the privacy and efficiency for individual parties. In this paper, we design a bidirectional efficiency-privacy transferable (BEST) authentication protocol to address this issue. In a relatively secure domain, BEST works in an efficient manner to authenticate batches of tags with less privacy guarantee. Once the tags flow into open environment, BEST can migrate to provide stronger privacy protection to the tags with moderate efficiency degradation. The analytic result shows that BEST can well adapt to the RFID-enabled supply chain.
    Keywords: RFID; tag; product management; supply chain; authentication; privacy; communication efficiency; wireless device; secure protocol; dynamic requirements.
  • An Efficient Mutual Distance Bounding Protocol over a Binary Symmetric Noisy Communication Channel   Order a copy of this article
    by Hoda Jannati, Abolfazl Falahati 
    Abstract: Distance bounding protocols have been suggested to protect an RFID communication system against relay attack. In such protocols, a verifier establishes an upper bound for the physical distance between a user and itself as well as authenticating the user. Recently, mutual distance bounding protocols in which both communication parties play not only as a user but also as a verifier have been proposed to be deployed for secure positioning protocols. In this paper, the performance of the existing mutual distance bounding protocols is analyzed over a noisy communication channel. The analytic results show that these protocols provide a much higher rejection probability of a valid user due to channel errors than distance bounding protocols. Furthermore, a novel method is proposed to convert every distance bounding protocol into a mutual distance bounding protocol. Within this method, for each one of the two communication parties, the produced mutual distance bounding protocol provides the performance and security level exactly equal to those of its own associated distance bounding protocol at the same noisy environment, without transmitting any extra messages at the end of the protocol.
    Keywords: Mutual distance bounding protocol; Distance fraud attack; Mafia fraud attack; Relay attack; False-accept probability; False-reject probability; Rapid bit exchange.
  • An Energy-Efficient Two Phases Cluster Head Selection in Corona-Based Wireless Sensor Networks   Order a copy of this article
    by Chung-Shuo Fan 
    Abstract: Due to unbalanced traffic pattern of wireless sensor networks (WSNs), larger load may be imposed to CHs (cluster heads) around the sink. Under this situation, CHs closer to the BS drain their energy earlier than those farther away from the sink. This paper first calculates cluster density of each corona according to the energy consumption of each CH. Then, this paper defines the range of CH candidates in phase 1 and phase 2 in order to choose the suitable CH so that sensor nodes forward data toward the BS and reduce the energy consumption. This paper further adopts cluster maintenance, which implement the cross-level data transmissions when specific conditions happen. Simulation results show that the proposed TPS (Two Phases cluster head Selection in WSNs) effectively prolongs the network lifetime and reduces the energy consumption over LEACH (Low Energy Adaptive Clustering Hierarchy), and MR-LEACH (multi-hop routing with LEACH).
    Keywords: WSNs; wireless sensor networks; energy efficiency; clustering; cluster head.
  • Modeling Software Fault Management with Runtime Verification   Order a copy of this article
    by Xingjun Zhang, Yan Yang, Endong Wang, Ilsun YOU, Xiaoshe Dong 
    Abstract: To achieve the software fault tolerance at runtime, base on runtime verification techniques, this paper proposes a runtime model of running program, which is used to define the actions and constrains for runtime software fault management. This model contains the descriptions of event, path, scope and adjustment. A runtime fault management system prototype, which mainly includes the rule description, event acquisition, fault diagnosis and handling, is implemented to verify the model. Two test cases are used to estimate the effect of the prototype, and the results show that this method can handle faults successfully at runtime.
    Keywords: software fault tolerance, runtime verification,runtime model
  • Optimizing Sink-Connected Barrier Coverage in Wireless Sensor Networks   Order a copy of this article
    by Yung-Liang Lai, Jehn-Ruey Jiang 
    Abstract: This paper proposes an algorithm to solve the sink-connected barrier coverage optimization problem, which is concerned with how to select randomly deployed sensor nodes of a wireless sensor network (WSN) to reach two optimization goals: (1) to maximize the degree of barrier coverage with the minimum number of detecting nodes, and (2) to make the detecting nodes sink-connected with the minimum number of forwarding nodes. The detecting nodes are those for detecting intruders crossing a belt-shaped area of interest. On detecting intruders, they send intruding event notifications to one of the sink nodes with the help of the forwarding nodes to relay the notifications. We prove the optimality of ONSA, perform simulations for ONSA, and compare the simulation results with those of a related algorithm to show ONSAs advantages.
    Keywords: Wireless sensor networks; Barrier coverage; Maximum flow minimum cost algorithm; Sink connectivity; Energy efficiency
  • A SMART SAFETY CANE FOR HUMAN FALL DETECTION   Order a copy of this article
    by Ping Hsu Chen, Yung-Hui Li, Che Wun Chiou, Chiou-Yng Lee, Jim-Min Lin 
    Abstract: Lots of countries have gradually become an aging society, therefore, the safety issues of the elderly attract more and more attentions. Falling is one of the major reasons for the accidental injuries of the elderly, and many times such accidents have become irreparable regrets because of the delayed arrival of the ambulances. Therefore, how to detect the instances of fall of the elderly, and how to provide medical care to them immediately after such accident happens are extremely important. Many old people choose to use a cane to assist walking. In this study, we propose to attach to the cane with intelligent embedded system with acceleration detection ability. Such system is able to collect the characteristics of the position of the cane when it is used by the elderly in real time. We analyze the data with finite state machine in order to detect the fall accidents of the elderly. The smart cane is able to send alarm and location of the elderly to the hospital as soon as such accidents are detected, so that the ambulance can be dispatched immediately after the accident happened.
    Keywords: Embedded System, Android Smart Phone, Smart Safety Cane, Human Fall Detection, Finite-State Machine (FSM)
  • Performance Analysis on Network Connectivity for Vehicular Ad Hoc Networks   Order a copy of this article
    by Ruifeng Chen 
    Abstract: This paper proposes a simplified but reasonable uninterrupted highway model to evaluate the network connectivity performance for vehicular ad hoc networks (VANETs) from the view of both individual vehicle and global network. Three parameters: conditional connectivity of the communication pair of individual vehicles, global network connectivity probability, and the vehicle isolation probability are investigated. By combining the probability density function of inter-vehicle initial distance and the distribution of vehicles' relative speed, which are both derived in this paper, the closed-form of conditional connectivity is obtained. To derive the closed-forms of network connectivity and vehicle isolation probabilities, the analytical model takes into consideration the key factors such as communication range, vehicle speed, and enter intensity. The analytical results are validated by extensive simulations. Our derived highway network connectivity model could be applied in the study of a number of metrics related to connectivity in vehicular ad hoc networks.
    Keywords: Vehicular Ad Hoc Networks; connectivity performance; isolation probability; vehicular communications.
  • Cooperative Opportunistic Network-coded Transmission Strategy for Wireless Mesh Networks   Order a copy of this article
    by Ke Xiong, Pingyi Fan, Su Yi, Ming Lei, Zhangdui Zhong 
    Abstract: Opportunistic Network Coding (ONC) is a promising technology to implementrnnetwork coding in practical systems. Compared with traditional network coding, the main advantage of ONC is that it allows the encoding node to decide whether it employs network coding or not based on the status of all its input streams. However, due to the nature of fading, wireless links may not always be with high quality. So, the performance gain of ONC over traditional methods may be decreased due to wireless links in deep fading. Fortunately, some techniques, such as cooperative diversity and ARQ (Automatic Repeat reQuest) can be used to mitigate it. In this paper, we consider a wireless mesh network model, where two sources want to transmit their information to their own destination, respectively, via the help of a common relay node. In order to improve the network performance by taking the advantage of ONC, ARQ and cooperative diversity, we propose a new cooperative opportunistic network-coded transmission strategy. The advantage of our proposed CP-ONC over ONC is that it employs truncated ARQ and cooperative diversity to enhance the reliability of the wireless links so that more network coding opportunities can be obtained in CP-ONC. We analyze the system performance in terms of network throughput and delay, where we derive some explicit expressions for them. Extensive simulations are presented, which show that our proposed CP-ONC achieves higher system performance gain over ONC in terms of network throughput and average delay, especially in low signal to noise ratio (SNR) region. Besides, we also discuss the impact of the maximum limit of the number of time slots for truncated ARQ and the impact of network topology on the system performances.
    Keywords: Cooperative Communications; Network Coding; Opportunistic NetworkrnCoding; Cooperation diversity; Automatic Repeat reQuest.
  • Localized Sensor Direction Adjustments with Geometric Structures of Voronoi Diagram and Delaunay Triangulation for Directional Sensor Networks   Order a copy of this article
    by Tien-Wen Sung, Chu-Sing Yang 
    Abstract: A directional sensor network consists of directional sensors instead of the omnidirectional ones in the conventional wireless sensor networks. The sensing coverage of a directional sensor network depends on the directionality and size-specific sensing angle of the sensors. The conditions are dissimilar from those of omnidirectional sensor networks for researches, especially on the sensing coverage. There exists a great number of researches aimed at coverage issues of omnidirectional sensor networks. Some of these researches utilized the geometric structure such as Voronoi Diagram or Delaunay Triangulation for solving the coverage problems. For field coverage problem in directional sensor networks, the geometric structures of Voronoi Diagram and Delaunay Triangulation have not drawn the attention of researchers. This study utilized Voronoi Diagram and Delaunay Triangulation and proposed four basic distributed and localized sensor direction adjustment algorithms with the characteristics of these two geometric structures to explore the field coverage improvement in directional sensor networks. The simulation results and comparisons of coverage performance of the proposed four basic algorithms are provided. They can give the clarity of the performance results and have a reference value for future advanced studies on various coverage issues in directional sensor networks.
    Keywords: Directional sensor network; Geometric structure; Voronoi Diagram; Delaunay Triangulation; Sensor field coverage
  • A One-Hop Information Based Geographic Routing Protocol for Delay Tolerant MANETs   Order a copy of this article
    by Lei You, Jianbo Li, Changjiang Wei, Chenqu Dai 
    Abstract: Delay and Disruption Tolerant Networks (DTNs) may lack continuous network connectivity. Routing in DTNs is thus a challenge since it must handle network partitioning, long delays, and dynamic topology. Meanwhile, routing protocols of the traditional Mobile Ad hoc NETworks (MANETs) cannot work well due to the failure of its assumption that most network connections are available. In this article, a geographic routing protocol is proposed for MANETs in delay tolerant situations, by using no more than one-hop information. A utility function is designed for implementing the under-controlled replication strategy. To reduce the overheads caused by message flooding, we employ a criterion so as to evaluate the degree of message redundancy. Consequently a message redundancy coping mechanism is added to our routing protocol. Extensive simulations have been conducted and the results show that when node moving speed is relatively low, our routing protocol outperforms the other schemes such as Epidemic, Spray and Wait, FirstContact in delivery ratio and average hop count, while introducing an acceptable overhead ratio into the network.
    Keywords: Geographic Routing; Protocol; Delay Tolerant Networks; Mobile Ad-Hoc Networks; One-hop Information.
  • Joint Relay Assignment and Bandwidth Allocation for All-to-One Communication in Cooperative Networks   Order a copy of this article
    by Hongli Xu 
    Abstract: Bandwidth allocation is an efficient way for throughput optimization in wireless mesh networks (WMNs). Recently, cooperative communication is regarded as a promising technology to improve the transmission capacity of wireless links. Accordingly, this paper pursues the objective of network throughput maximization through cooperative communication and bandwidth allocation while achieving the max-min fairness. As relay assignment plays an important role for cooperative communication, we first define the joint relay assignment and bandwidth allocation (JRB) problem for WMNs. The problem is formulated into the integer programming, and shown to be NP-hard by reduction from the max-min association control problem. Then, this paper presents a distributed algorithm TRBA to solve the JRB problem. In the algorithm, relay assignment and bandwidth allocation are jointly implemented with local decision, so that the network throughput can be enhanced greatly. The theoretical analyses show that the proposed algorithm can reach the approximate performance of O(1) for the JRB problem. Moreover, another algorithm, called ITRBA, is presented to improve the average bandwidth of all mesh nodes while still preserving the max-min fairness compared with the TRBA algorithm. Our simulation results demonstrate that the proposed algorithms can almost reach the same network throughput as the optimal method, and improves the network throughputs about 20.0% more than that of the pervious bandwidth allocation method.
    Keywords: Cooperative Communication, Relay Assignment, Bandwidth Allocation, Network Throughput, Max-Min Fairness
  • Polling in the Frequency Domain: A New MAC Protocol for Industrial Wireless Network for Factory Automation   Order a copy of this article
    by Yang Xiao, Junru Lin, Wei Liang, Haibin Yu 
    Abstract: Wireless technologies are becoming more and more attractive for industrial communication. In the field of factory automation, the high communication requirements in terms of predictability, reliability and real-time make the adoption of wireless technologies challenging, due to the inefficiency of the wireless physical layer and nondeterministic media access control (MAC) protocols. In this paper, a Frequency Domain Polling MAC protocol (FDP-MAC) is proposed, which takes advantage of the Orthogonal frequency-division multiplexing (OFDM) technology to achieve simultaneously polling. In the FDP-MAC, a dynamic Time division multiple access (TDMA) scheduling and a downlink acknowledgements aggregation method are also presented to improve the communication efficiency further. We validate the effectiveness of FDP-MAC through simulations, and results indicate that FDP-MAC can meet typical factory automation applications communication requirements.
    Keywords: Polling , Frequency Domain, MAC , Industrial Wireless Network, Factory Automation
  • Adaptive Filtering Based Collaborative Actuation for Wireless Sensor and Actuator Networks   Order a copy of this article
    by Lei Mo, Bugong Xu 
    Abstract: Wireless sensor and actuator networks are emerging as a new generation of sensor networks. To accomplish effective sensing and acting tasks, efficient coordinate mechanisms among the nodes are desirable. As an attempt in this direction, this paper develops a collaborative estimation and control mechanism, which addresses the nodes coordination in a distributed manner. First, we discuss the system model and system partition that are used to construct the distributed architecture. Then, a collaborative estimation and control scheme is proposed to coordinate sensor and actuator nodes. This scheme includes two components, namely recursive least squares based federated Kalman filter (RLS-FKF) and PID neural network (PIDNN). It schedules the corresponding nodes based on the characteristics of current events, deals with data fusion and system estimation problems through RLS-FKF, and utilizes PIDNN controller to improve system transient and steady-state responses. Simulations demonstrate the effectiveness of proposed methods.
    Keywords: Wireless sensor and actuator networks; Recursive least squares; Federated Kalman filter; PID neural network.
  • MMS-MVN: A Multimedia Multicast Scheduling method for Multi-hop Vehicular Networks   Order a copy of this article
    by Miao Hu, Zhangdui Zhong, Chih-Yung Chang 
    Abstract: Emerging technologies for vehicular Ad Hoc networks (VANETs) have aroused tremendous attentions in both the safety and entertainment related applications. In this paper, the multimedia multicast scheduling design problem for multi-hop vehicular networks is studied. Many previous works on multimedia scheduling problem focused on the design for one-hop networks or multi-hop networks with fixed relay stations. However, for multi-hop vehicular networks, with the possibility that each vehicle can be selected as relay and various channel conditions etc., the optimal scheduling scheme is hard to obtain. We develop a heuristic scheduling algorithm to approach the performance of the intractable optimal scheduling scheme. Simulation results show that performance of the proposed heuristic algorithm approaches the optimal results and shows some good properties against other algorithms, which verifies the contribution of our work.
    Keywords: layered multimedia, multicast schedule, multi-hop transmission, VANETs
  • TIE-MAC: Tolerable Interference Estimation based Concurrent Medium Access Control for WLAN Mesh Networks   Order a copy of this article
    by Lei Lei, Shengsuo Cai, Liang Zhou, Xiaoming Chen 
    Abstract: This paper presents TIE-MAC, tolerable interference estimation based concurrent medium access control protocol for WLAN mesh networks. The goal is to increase spatial reuse, achieve high throughput and reduce average energy consumption through exploiting concurrent transmissions among neighboring nodes. TIE-MAC confirms that the tolerable interference of the receiver plays a key role in determining the efficiency of concurrent transmission scheduling, and puts forward a novel tolerable interference estimation mechanism, enabling the receivers to precisely estimate their tolerable interference. Meanwhile, a Concurrent Transmission Gap (CTG) is inserted between the transmission of the RTS/CTS and data packets to offer the nodes in the vicinity of the receiver the chance to schedule possible overlapping transmissions. The size of the CTG is optimized using an exponential smoothing model based adjustment algorithm. Moreover, sequenced ACKs are introduced in TIE-MAC and used in combination with the tolerable interference estimation mechanism to avoid possible collisions among different concurrent transmissions. Simulation results show that TIE-MAC gains better throughput and energy consumption performance in comparison with existing concurrent transmission protocols as well as the active WLAN mesh standard.
    Keywords: WLAN mesh networks; concurrent medium access control; tolerable interference estimation; throughput enhancement; energy saving
  • Matrix-based Key Pre-distribution Schemes in WMNs Using Pre and Post Deployment Knowledge   Order a copy of this article
    by Yuexin Zhang, Li Xu, Xinyi Huang, Jie Li 
    Abstract: Like other types of wireless networks, wireless communication in wireless mesh networks (WMNs) is vulnerable to many malicious activities. Thus it is a must to protect wireless transmission by proper security measures. As a fundamental security technology, symmetric key pre-distribution has been widely studied to ensure the security of wireless communication. This paper presents two matrix-based pairwise key establishment schemes for mesh clients. In our schemes, a mesh client only needs to pre-load an independent key seed which can be used to generate a column of secret matrix. It can establish pairwise keys with neighbor clients after mesh routers broadcast public matrices. Motivated by this heterogeneity (mesh routers are much more powerful than mesh clients, both in communication and storage), energy-consuming operations can be delegated to mesh routers to alleviate the overhead of mesh clients when they establish pairwise keys. By using pre and post deployment knowledge, neighbor mesh clients in our scheme can directly establish pairwise keys with a very light communication and storage cost.
    Keywords: Pairwise Key; Matrix; Pre and Post Deployment Knowledge; Wireless Mesh Networks; Wireless Sensor Networks.
  • Introducing Extreme Data Storage Middleware of Schema-free Document Stores using MapReduce   Order a copy of this article
    by Kun Ma, Bo Yang 
    Abstract: Referred to NoSQL, schema-free databases feature elasticity and scalability in combination with a capability to store big data and work with Cloud computing systems, all of which make them extremely popular. In particular, the creation of the data warehouse is gaining a significant momentum. Although large corporate early adopters paved the way, since then, data warehousing has been embraced by organizations of all sizes. However, there are few publications on data warehouse of NoSQL. In this paper, an extreme data storage middleware (EDSM) of schema-free document stores using MapReduce is presented to address the issue of formulating no redundant data warehouse with small amount of storage space for the purpose of their composition in a way that utilizes the MapReduce framework. First, the definition of cell with an effective lifecycle tag is given. Second, the architecture and extreme data storage principles are presented. At last, the capture-map-reduce procedures are discussed to create the NoSQL data warehouse. The experiment is shown to successfully build the NoSQL data warehouse reducing data redundancy compared with document with timestamp and lifecycle tag solutions. Our experiment also provides insight into some of the key challenges and shortcomings that researchers and engineers face when designing the data warehouse middleware.
    Keywords: extreme data storage; historical data; change data capture; MapReduce; NoSQL; lifecycle tag; data warehouse; data redundancy
  • Experimental Analysis of CCA Threshold Adjusting for Vehicle EWM transmission in V-CPS   Order a copy of this article
    by qingwen han, Lingqiu zeng, Le Yang, Yuebo Liu 
    Abstract: Vehicular Cyber-physical System (V-CPS) offers the potential to significantly improve the safety, comfort and entertainment to motorists. The topic of emergency warning message (EWM) transmission is still most important for V-CPS because of the thousands of lives taken by traffic accident. The EWM dissemination is expected to inform the related vehicles in time, and in this paper, we proposed a new EWM dissemination mechanism based on an improved CCA method to reduce the transmission delay by shorten the sensing time for idle channel. Experimental results obtained from the testbedEyeNetshowed that for 3-hop manner, the proposed mechanism employing an appropriate CCA threshold setting can shorten the transmission delay with 12ms, while under one hop condition, it should guarantee a relative high successful dissemination rate about 60%.
    Keywords: V-CPS; information dissemination; emergency warning message; regional flooding; CCA
  • Tour and Path Planning Methods for Efficient Data Gathering using Mobile Elements   Order a copy of this article
    by Khaled Almi'ani, Anastasios Viglas, Lavy Libman 
    Abstract: Several studies in recent years have considered the use of mobile elements for data gathering in wireless sensor networks, so as to reduce the need for multi-hop forwarding among the sensor nodes and thereby prolong the network lifetime. Since, typically, practical constraints preclude a mobile element from visiting all nodes in the sensor network, the solution must involve a combination of a mobile element visiting a subset of the nodes (cache points), while other nodes communicate their data to the cache points wirelessly. This leads to the optimization problem of minimizing the communication distance of the sensor nodes, while keeping the tour length of the mobile element below a given constraint. Based on the structure of the tour we investigate two variations of this problem. We start by considering the case where the mobile element tour should starts and ends at a predefined sink. Then we consider the unrestricted case, where the mobile element tour is not required to include the predefined sink node. Several algorithms in existing literature have tackled these problems by separating the construction of the mobile element tour from the computation of the multi-hop forwarding routes to the cache points. In this paper, we propose new algorithms that alternate between these phases and iteratively improve the outcome of each phase, based on the result of the other. We compare the resulting performance of our algorithm with the best known comparable schemes in the literature.
    Keywords: Data gathering, mobile elements, path planning algorithms
  • A Cross-Layer Approach for Multi-Layer Multicast Routing in Multi-Channel Multi-Radio Wireless Mesh Networks   Order a copy of this article
    by Leili Farzinvash, Mehdi Dehghan 
    Abstract: In this paper we consider multicast applications with bandwidth heterogeneous receivers in Multi-Channel Multi-Radio Wireless Mesh Networks (MC-MR WMNs). Multi-layering is a well-established approach to handle bandwidth heterogeneity of the receivers. Existing multi-layering schemes are proposed to address only single-channel settings. In the context of MC-MR WMNs, the channel assignment problem will be coupled with multicast routing, thus necessitating a cross-layer solution. In this paper, we propose an optimal cross-layer model, which aims at maximizing the total number of obtained layers by the receivers. We include network coding in our design to take advantage of its capacity boosting in multicast routing. To alleviate time complexity of the optimal model, we propose Grouping-based Multi-Layer Multicast (GMLMC) algorithm, which yields close to optimal throughput in polynomial time. GMLMC performs channel assignment firstly. Then, the layers are processed consecutively to determine the obtained layers by the receivers, with respect to their available bandwidths. To process a layer in polynomial time, the receivers are partitioned into constant-size groups. Next, subscribing the receivers to the layer is investigated in each group independently. Our extensive simulations show that the throughput of GMLMC is no less than 96% of the optimum. In addition, we study the pattern of layer reception to the receivers in GMLMC. It turns out that the generated results of GMLMC resembles very much to the optimal solutions in this respect.
    Keywords: wireless mesh networks; multicast; multi-layer; network coding; channel assignment; multi-channel multi-radio systems; cross-layer optimization.
  • Verifying Vehicle Control Systems by Using Process Calculi   Order a copy of this article
    by Gabriel Ciobanu, Armand Rotaru 
    Abstract: The paper deals with the safety of car control systems in which vehicle-to-vehicle interactions are described in a modular and compositional manner. Such a description simpli fies a complex veri fication process, which involves control decisions regarding acceleration, deceleration, lane switching and breaking distance. We focus on the problem of adjusting vehicle speed in order to maintain a proper distance between vehicles on the same lane. The components of the control system are represented as processes in the process algebra Communicating Sequential Processes, and the compositional parallel operator is used to describe the whole system. Safety properties are formally verifi ed by employing the Concurrency Workbench of the New Century tool.
    Keywords: Adaptive Cruise Control; Communicating Sequential Processes; Model Checking; Concurency Workbench of the New Century.
  • A Linear Regression-Based Delay-Bounded Multicast Protocol for Vehicular Ad Hoc Networks   Order a copy of this article
    by Tong-Ying Juang 
    Abstract: Vehicles inform emergent events and car accidents by using a routing protocol in vehicular ad hoc networks (VANETs), which is a wireless ad hoc network that operate in a vehicular environment to provide communication between vehicles. This study focuses on a linear regression-based delay-bounded multicast protocol that delivers messages to numerous destination regions within a user-defined delay time for each region by minimizing radio usage. In our protocol, a message can be delivered to destination regions by using a hybrid of data muling (carried by a vehicle) and forwarding (delivered through a radio). Thus, if the available time is sufficient, then the message is delivered through muling; otherwise, the message is delivered by forwarding. The proposed protocol comprises two schemes: the greedy and centralized schemes. The simulation results indicated that the proposed multicast protocol performed more favorably than existing protocols did regarding total transmitted bytes.
    Keywords: vehicular ad hoc networks (VANETs); multicast; routing protocol; delay-bounded; linear regression.
  • Design and Implementation of an IoT Multi-Interface Gateway for Establishing a Digital Art Interactive System   Order a copy of this article
    by Zhi-yong Bai, Chin-Hwa Kuo, Tzu-Chia Wang 
    Abstract: The Internet of Things (IoT) can be established by connecting smart objects in a wireless manner. However, a variety of technologies of wireless networks, including Bluetooth, ZigBee, WiFi and infrared, which have been embedded into smart objects or controllers, cannot exchange information since they apply different standards or even work on different frequencies. To provide information exchange in heterogeneous networks, this paper proposes the design and implementation an IoT multi-interface gateway, which can transform the information into a data which can be recognized by various smart objects. In the interactive system, the IoT multi-interface gateway can be used for digital arts or some smart spaces that can automatically control traditional TV, air condition, smart meter, sphygmomanometer, smart phone, etc. The implementation shows that the IoT gateway can exchange data among various smart objects that use different wireless technologies and also guarantee the stability of data conversion time.
    Keywords: digital arts; gateways; heterogeneous networks; identification; interactive systems; IoT; internet of things; smart objects
  • A Reverse Auction Algorithm for Carrier Allocation in Femtocells for Multimedia Applications   Order a copy of this article
    by Zhibin Gao, Hua-Pei Chiang, Lianfen Huang, Yannan Yuan, Huaiyu Dai, Yueh-Min Huang 
    Abstract: An efficient carrier allocation algorithm is important for Self-Organized Networks (SON). SON can significantly improve network performance and user experience which greatly help relieve the heavy loading of the current multimedia applications for mobile environments. This paper proposes a distributed algorithm for carrier allocation using a reverse auction algorithm, wherein the original cells affected by newly added cells self-organize into auction groups to facilitate new carrier allocation. The computational overhead required to adapt to topology changes can be significantly reduced compared with the conventional topology-based approaches that ignore prior assignments. The number of original cells affected by the reallocation is as small as possible in the reverse auction algorithm while optimizing carrier allocation. We investigate the algorithm performance in various scenarios. Our results indicate that the reverse auction algorithm exhibits significant advantages compared to traditional approaches, especially in highly dynamic networks where frequent resource re-allocation is needed.
    Keywords: carrier allocation; small-scale network; reverse auction algorithm; network capacity

Special Issue on: "Security Aspects in Pervasive and Ubiquitous Computing,"

  • A Quantitative & Knowledge-Based Approach to Choosing Security Architectural Tactics   Order a copy of this article
    by Suntae Kim 
    Abstract: This paper presents a quantitative approach to choosing security architectural tactics using architectural tactic knowledge base. An architectural tactic is an architectural design building block pertaining to a software quality. The tactic knowledge base is a tactic repository composing of architectural tactic specifications defined in Role Based Metamodeling Language (RBML) and their relationships expressed in a feature model. In this paper, a cost of an architectural tactic is estimated by using the use case points method, and a level of tactic contribution for non-functional requirements(NFRs) is predicted by the Analytic Hierarchy Process(AHP) and sensitivity analysis. Then, the proposed approach suggests the best possible fit which is likely to satisfy NFRs. We applied the approach to choosing security architectural tactics for building software architecture of an on-line trading system.
    Keywords: Security Architectural Tactics, Secure Software Architecture, Quantitative Tactic Selection, Architectural Tactic Knowledge Base

Special Issue on: "Dynamism and Mobility Handling in Mobile and Wireless Networking,"

  • Developing a Wireless Based Dynamic Management Mechanism for Intravenous Drip Scheduling   Order a copy of this article
    by Chien-Liang Chen, Nan-Chen Hsieh, Lun-Ping Hung 
    Abstract: In this rapidly developing high-tech environment, building a nursing information system is essential. When an emergency occurs, nurses must immediately remove obstacle interrupting medical care to assist medical treatment successfully. In this paper, a system built in a mobile nursing station accompanied by a high-tech device installed in the infusion drip equipment transmitting signals through a ZigBee wireless network is proposed. This system uses a dynamic wireless infusion monitoring mechanism. When an emergency occurs, the intravenous drip sends out an alert message through the wireless environment to the system in the mobile nursing station. The system will reschedule previous processing ranks to assist nurses in taking care of routine medical operations efficiently. By applying this system, nurses can devote themselves to providing better quality medical care and claims for medical negligence or medical malpractice can be reduced.
    Keywords: mobile nursing station; infusion monitoring; ZigBee; Nursing Information Systems
  • SocioCar: A Transient Social Vehicular Network   Order a copy of this article
    by Rasool Esmaeilyfard, Faramarz Hendessi 
    Abstract: The increasing use of vehicles and the heavy traffic emerged in metropolises have both turn to an important part of people's daily routine. This situation could provide a unique opportunity for some kind of social communication among people. However, this social communication has its requirements and constraints. In this paper, we introduce the notion of SocioCar in order to develop a transient social vehicular network service. This service inspires the users to communicate quickly by reducing social constraints. In this regard, one of the key points in this paper is the idea to adapt the user identity and its role in rapid communication. Furthermore, we integrate our design with a user social classification method using Bayesian Networks with an aim to effectively highlight the desired users and predict users characteristics. Through this approach, we investigate the social classification model and conduct a user study to probe the usefulness of social network.
    Keywords: transient social networking; social service middleware; avatar; privacy; vehicular ad-hoc networks (VANET); social classification.
  • Spectrum Sharing Model for OFDMA macro-femtocell networks   Order a copy of this article
    by Rebeca Estrada, Hadi Otrok, Zbigniew Dziong, Hassan Barada 
    Abstract: Enhancing the network throughput while supporting non-uniform user distribution and dense deployment of femtocells is a challenge in OFDMA networks. Previous research works provide approaches based on spectrum partitioning and spectrum sharing for macro-femtocell networks. Few proposed interference management approaches have been investigated without considering user mobility. In this paper, we target the optimization of resource allocation in macro-femtocell networks taking into account the user distribution over macrocell coverage area and femtocells dense deployment. We propose a spectrum sharing approach that aims to maximize the network throughput based on Linear Programming. Interference mitigation is performed through the power adaptation in both tiers while guaranteeing the QoS transmission requirements. Our solution is able to: (1) fairly allocate macrocell resources to each zone taking into account the user distribution over the macrocell coverage area, (2) optimally reuse of the bandwidth allocated to inner zone inside the femtocells located in outer zone, and (3) optimally determine the serving base station, subcarriers and respectiverntransmitted power for downlink transmissions per zone taking into account user locations and demands in any given period. Performance analysis is presented under incremental traffic load and realistic scenarios where user mobility is considered. Simulations are conducted to show a comparison of the proposed model with two spectrum partitioning approaches with and without partial bandwidth reuse.
    Keywords: Linear Programming; OFDMA macro-femtocell networks; Subcarrier Reuse; Power Control.
  • Cross Layer Trigger based Handover Scheme for Mobile WiMAX Networks   Order a copy of this article
    by sudesh pahal, Brahmjit Singh, Ashok Arora 
    Abstract: WiMAX networks have recently emerged to be a cost effective solution to provide broadband access over a large coverage area. To maintain service continuity and guarantee the QoS in real time applications for mobile users, handover delay is one of the main challenges while designing handover algorithms. In this paper, cross layer trigger based handover scheme is proposed which will be able to offer uninterrupted services to mobile users. The basic idea behind this scheme is to achieve a global optimality by utilizing the advantages of cross layer interactions between link layer and network layer. The cross layer triggers generated at lower layers, intimate higher layers about an imminent handover and allow execution of handover processes in Layer 2 (L2) and Layer 3 (L3) simultaneously. In addition, information about location and direction of movement of mobile is used to reduce scan delay. The analytical and simulation results show that the proposed mechanism enhances the handover performance in terms of handover delay and latency, which, in turn, reduces signaling overload and service disruption significantly.
    Keywords: Cross layer; Mobile WiMAX; FMIPv6; Handover; delay; Latency; Trigger;
  • SPEED-3D: a Geographic Routing Protocol for 6LoWPAN Networks   Order a copy of this article
    by Stefano Bocchino, Matteo Petracca, Paolo Pagano, Marco Ghibaudi, Giuseppe Lipari 
    Abstract: The integration of the Wireless Sensor Network (WSN) technology in the Internet world is a necessary step towards the full accomplishment of the Internet of Things (IoT) vision. In order to reach a seamless integration of tiny mote devices in Internet, the IPv6 addressing method and communication protocols developed for the IoT must be modi ed or adapted to match the WSN requirements. This adaptation process is started in the 2007 with the standardization of the IPv6 protocol over Low power Wireless Personal Area Networks (6LoWPAN). In such a scenario, we propose SPEED-3D, an extension of the SPEED geographic routing algorithm, adapted to 6LoWPAN networks that caters for 3D routing. SPEED- 3D avoids the creation of routing tables, and has a very low memory occupation; it also supports load balancing and ow shaping; nally, thanks to the presented extension, it is able to work seamlessly in a 3D setting (e.g., a tall building). In the paper, we rst present SPEED-3D in 6LoWPAN networks by detailing the encapsulation of all messages in the IEEE802.15.4 medium access control protocol and the new functionality provided thanks to the IPv6 standard, then we present its implementation on a real-time kernel and its performance in a realistic indoor scenario.
    Keywords: Wireless Sensor Networks; 6LoWPAN; IoT; Routing algorithm; Real-Time.

Special Issue on: "Emerging Technologies for Ubiquitous Communications, Computing and Applications in Ad-hoc Networks,"

  • Towards Optimizing Routing Overhead in Wireless Multi-hop Networks   Order a copy of this article
    by Nadeem Javaid, Ayesha Bibi, Saad Noor Mohammad 
    Abstract: Routing protocols in Wireless Multi-hop Networks (WMhNs) are responsiblernfor efficient path calculations. Reduction in drop rates in WMhNs requires low bandwidth consumption as well as low delay which is caused by excessive transmissions and processing delays. Reactive routing protocols are aimed to optimize broadcast cost and time consumption during routing. In high dynamic WMhNs, reactive routing protocols provide quick convergence through faster route discoveries and route maintenances. In this paper, we select three most commonly used reactive protocols; Ad-hoc On-demand Distance Vector (AODV), Dynamic Source Routing (DSR) and DYnamic MANET Ondemand (DYMO) and model their energy cost and time cost of Expanding Ring Search (ERS) algorithm. A novel contribution of this work is tuning of route discovery and route maintenance parameters of chosen protocols to minimize routing overhead. For analytical comparison of selected protocols, we simulate default and enhanced versions of these protocols with three performance metrics; throughput, Normalized Routing Load (NRL) and End-to-End Delay (E2ED) using NS-2. From modeling and analytical comparison, we deduce that by adjusting Time-To-Live (TTL) in search sets of ERS algorithm withrnrespective waiting time are more useful for reducing bandwidth and locating time in chosen protocols. Moreover, for reliable transmission and efficient performance, reactive protocols need immediate detection of link breakage along with quick repairement strategies for re-establishment of routes such as Local Link Repair (LLR) and Packet Salvaging (PS).
    Keywords: Routing; AODV; DSR; DYMO; Discovery; Maintenance; Expanding; Ring; Search
  • A Transmission Protocol Based on Network Coding in Many-to-one Delay Tolerant Networks   Order a copy of this article
    by Chuang Ma, Chih-Yin Lee 
    Abstract: In Delay Tolerant Networks, the delay of packets is long due to the intermittent connections caused by the mobility of nodes. Epidemic Routing Protocol can reduce the delay time and raise the packet delivery rate by replicating and spread copies of source packets in the networks, but it inevitably exhaust memory resources and network bandwidth. In this paper, we propose a network coding with limited buffer routing protocol based on two network models, single packet network model and multiple packets network model. When a buffer of a node is full, two packets in the buffer are chosen randomly and encoded linearly together into a packet to save buffer space and improve the performance in many-to-one communications. Instead of applying network coding only to the packets that come from the same source nodes like in the unicast based models, we apply the network coding to the packets that are from multiple sources which are generated in the same period of time. Moreover, in the transmitting stage of our network coding routing protocol, we proposed two efficient approaches which can enhance the efficiency of information exchange and packets transmission in communications of delay tolerant networks.
    Keywords: Delay tolerant networks, epidemic routing, limited buffer, multicast, network coding
  • A Robust and Reliable Routing Based on Multi-hop Information in Industrial Wireless Sensor Networks   Order a copy of this article
    by Dariush Zolfaghari, Hassan Taheri, Amir Hossein Rezaie 
    Abstract: Due to considerable noise in the industrial environments, wireless packet transmission is usually unreliable. Designing an efficient routing algorithm for these environments poses significant challenges. Current routing algorithms consider the quality of service parameters such as node energies and delay, but packet losses need a novel strategy to compensate for the decline in signal to noise ratio (SNR) in noisy industrial environments. The proposed routing algorithm is based on multi-hop neighbor information. The multi-hop neighbor nodes provide vital information for the source node, enabling it to select the proper relay node. In noisy channel conditions the transmitted packets should meet the deadline and be delivered to the sink node on time. Performance evaluation via simulations indicates significant improvement in reliability, lifetime of network and real-time performance. The proposed algorithm is more robust than previous methods. The most beneficial features of the proposed algorithm are its uniform distribution of energy among nodes and deliverance of deadline packets with the lowest losses.
    Keywords: Industrial Wireless Sensor Network (IWSN), real-time routing, reliability, multi-hop information, noise.
  • The Correlation Study for Parameters in Four Tuples   Order a copy of this article
    by Fei Song, Yige Zhang, Zhaoxu An, Huachun Zhou, Ilsun You 
    Abstract: For analyzing the characteristics of current Internet connections, this paper proposed several analytical schemes to study the correlation of parameters inside four tuples. We extracted the real trace in packet level from campus network border routers. No sampling method is added to maintain the full information. Firstly, different time bins are employed for exploring the single parameter variations comprehensively. Then, the potential association of parameters inside four tuples is investigated two-by-two. Thirdly, three tuples properties are shown and compared. The significance of source port is also discussed. Fol-lowing that, the duration and size for connections, i.e. four tuples, are studied. Some interesting observations are presented and explained. The influence of three and four tuples fluctuation is checked based on a new statistical scheme we proposed. Finally, the service type classification of connections and packets are demonstrated respectively. The distribution properties of differ-ent services are also declared. The conclusions summarize several unexpected phenomenon and the future work is pointed out at the end.
    Keywords: network measurement, four tuples, real data trace, connection properties

Special Issue on: "Advances in High Performance and Pervasive Modelling and Simulation in Intelligent Networking"

  • Action planning for multi-robot-based reconfigurable fixture   Order a copy of this article
    by Wojciech Szynkiewicz 
    Abstract: The paper presents a planning system for a self-reconfigurable fixture. The fixture is a multi-agent system composed a variable number of adaptable mobile robotic agents and a workbench on which these agents can move and lock. The paper proposes an approach for the generation of a~feasible action plan for the locomotion, reconfiguration, and positioning of robotic fixtures to support the thin-sheet workpiece near the operating machine-tool. The multi-agent action planning problem is converted to a Constraint Satisfaction Problem (CSP). CSP is a computational problem where the task is to decide for a given finite set of variables and constraints whether there is an assignment to the variables that satisfies all constraints. The proposed approach called Triple-CSP applies an incremental state search to solve three hierarchical planning tasks for the three components of each mobile agent: a supporting head placement, a~mobile base positioning, and a~parallel kinematic machine positioning, respectively. Thus, the planner takes into account all the relevant physical, geometrical, and time constraints.
    Keywords: reconfigurable fixture, multi-agent system, constraint satisfaction
  • A Framework for Comparative Performance Study on Virtualized Machines   Order a copy of this article
    by Jie Tao, Jiaqi Zhao, Karl Fuerllinger 
    Abstract: The virtualization technology has been widely used today in various research fields, including High Performance Computing, Grid Computing, Cloud Computing as well as server-client systems. The virtualization introduces advantages such as on-demand customized resource provision, easy management and support for multiple Operating Systems, etc. However, this technology also results in a performance loss due to the additional virtualization layer. To help application developers study the performance issues on virtualized multicore machines, we developed a tool framework with a set of performance tools that collect the runtime performance data and demonstrate the different runtime application behavior on both the physical machine and the virtual machine within a single view. We applied the tool framework to analyze a number of benchmark applications and conducted optimizations based on the analysis discovery. The initial experimental results show a significant performance gain.
    Keywords: Performance Tools; Virtualization; Code Optimization, Profiling
  • Design and Evaluation of a Quorum-based Synchronization Protocol of Multimedia Replicas   Order a copy of this article
    by Dilaware Doulikun, Ailixier Aikebaier, Tomoya Enokido, Makoto Takizawa 
    Abstract: We discuss how to efficiently and consistently manipulate multiple replicas of a multimedia object. Multimedia replicas are characterized in terms of not only data structure but also quality of service (QoS). Multimedia replicas are written in enriching and impoverishing types of write operations where some data is added and removed in a replica, respectively. Computation resources are spent to materialize, i.e. physically update multimedia replicas by encoding and decoding multimedia data. We discuss an extended multimedia quorum-based (EMQB) protocol to reduce the processing overhead of each replica. Here, a replica is not materialized in an impoverishing type of write operation.rnEven in an enriching type of write operation, only some number, not necessarily all of replicas in a write quorum are materialized. Hence, a newest, materialized replica may not be in a read quorum. Even if one newest replica is surely found in a read quorum, no newest replica might be materialized and a transaction cannot read any replica. In the EMQB protocol, replicas are randomly selected to be in a read quorum until a materialized replica is found.rnThe EMQB protocol is evaluated in terms of the total processing overhead of replicas compared with the quorum-based (QB) protocols. We show that the processing overhead of each replica can be reduced in the EMQB protocol compared with the QB and MQB protocols.rn
    Keywords: Quorum; Multimedia replica; Replication; Multimedia quorum; Extended multimedia quorum-based (EMQB) protocol
  • Dynamic task-scheduling based parallelization of watershed distributed ecohydrological model   Order a copy of this article
    by Lajiao Chen, Peng Liu, Yan Ma, Wei Xue 
    Abstract: Watershed distributed ecohydrological modeling require large amounts of computations which dramatically increased with the increasing area of the catchment. The traditional sequential computation techniques cannot meet the requirements of watershed ecohydrological modeling. Efforts have been paid to the parallelism of watershed distributed ecohydrological model. Most of these studies conducted parallelism at a granularity of sub-basin which is of low parallel efficiency and may cause unbalance load of computing resources. Few studies conducted parallelism at a granularity of grid cell. However, due to the interdependencies of grid-based tasks, the control logic of the parallel processing algorithm became very complex, leading to poor extensibility of the algorithm on parallel processing performance. In view of the existing problems, a novel scheme of dynamic task-scheduling based parallelism for watershed ecohydrological model was introduced. The basic concept of the approach is to design a strategy which decouple the grid based tasks into independent tasks and rank computation sequence of these tasks according to the interactions between upstream and downstream grids. A grid-based fully-distributed ecohydrological model Distributed Vegetation Optimality Model (DisVOM) is used as an example to illustrate the parallelism scheme. The model was firstly decoupled into grid-based tasks, and a dynamic task tree based on Directed Acyclic Graph (DAG) model was constructed for calculation schedule. The parallelism was realized by a critical path based schedule solution with job status queue. The proposed approach was applied in Walnut Gulch watershed in Arizona, USA. The result showed that this approach can highly improves the efficiency of watershed ecohydrological modeling with nearly six times speed up compared to the traditional sequential ecohydrological modeling. This could come to a conclusion that the dynamic task-scheduling based parallelism approach proposed in this study is valuable for watershed ecohydrological modeling.
    Keywords: watershed ecohydrological model; parallelization; dynamic task-scheduling; DAG model
  • AEDB Protocol Tuning with a Fast Efficient Parallel Multi-Objective Local Search   Order a copy of this article
    by Santiago Iturriaga, Sergio Nesmachnow, Patricia Ruiz, Pascal Bouvry, Bernabe Dorronsoro 
    Abstract: Mobile ad hoc networks are infrastructure-less communication networks spontaneously created by a number of mobile devices. Due to its highly fluctuating topology, finding the optimal configuration of communication protocols is a complex and crucial task. Additionally, different objectives must be usually considered. Small variation of the parameters values affects the performance of the protocol, promoting one objective while reducing another. Therefore, multi-objective optimization is needed for fine tuning the protocol. This work introduces a novel parallel multi-objective local search to optimize the AEDB broadcasting protocol in terms of coverage, energy used, broadcasting time, and network resources. The proposed method looks for appropriate values for a set of 5 variables that influence the behavior of the protocol to provide accurate tradeoff configurations in a reasonable short execution time. The new algorithm is validated versus efficient state-of-the-art multi-objective evolutionary techniques, offering high quality results in much shorter times, especially for high coverage solutions.
    Keywords: multi-objective optimization; broadcasting; energy efficiency; MANETs
  • High Performance Wireless Sensor Network Localization System   Order a copy of this article
    by Michal Marks, Ewa Niewiadomska-Szynkiewicz, Joanna Kolodziej 
    Abstract: In this paper we summarize the results of our research concerned with the development, implementation and evaluation of a software framework for wireless sensor networks localization - High Performance Localization System (HPLS). The system can be used to calculate positions of sensing devices (network nodes) in the deployment area, and to tune and verify various localization schemes through simulation. It provides tools for data acquisition from a workspace, estimation of inter-node distances, calculation of geographical coordinates of all nodes with unknown position and results evaluation. Received Signal Strength measurements are utilized to support the localization process. Trilateration, simulated annealing and genetic algorithm are applied to calculate the geographical coordinates of network nodes. The utility, efficiency and scalability of the proposed localization system HPLS have been justified through simulation and testbed implementation. The calculations have been done in parallel using the map-reduce paradigm and the HPC environment formed by a cluster of servers. The testbed networks were formed by sensor devices manufactured by Advantic Technology (clones of TelosB platform).rnA provided case study demonstrates the localization accuracy obtained for small-, medium- and large-size multihop networks.
    Keywords: Wireless Sensor Networks; localization; positioning; stochastic optimization; real life deployments; HPC; testbed verification
  • High Throughput Wavelet Coherence Analysis of Neural Series   Order a copy of this article
    by Jiaqing Yan, Dan Chen 
    Abstract: The real-time estimation of coherence amongst multiple neural signals from different brain areas is a critical issue in understanding brain functions. Currently, the wavelet coherence based on the Monte Carlo method (MC-WTC) is an effective algorithm to measure the time-frequency coherence of neural signals and could obtain a good time-frequency resolution. However, because this algorithm generates a large set of intermediate data, it could not be applied in real-time neural signal processing. To solve this problem, we develop a parallelized MC-WTC method with general-purpose computing on the graphics processing unit (GPGPU), namely, G-MC-WTC. The method divides MC-WTC into three major sub functions and speeds up the calculations using the CUDA toolkit. The optimization focuses on surrogate data generation, wavelet transform and matrix operations in coherence calculation. Simulation data showed that the G-MC-WTC can improve the runtime performance by almost 200 times comparing to the original sequential MC-WTC calculated using single CPU thread. This method has been applied to a visual-auditory EEG data and obtained the coherence information between different brain areas in real time when a subject performed different tasks. The result revealed a coherence difference in θ band at left temporal lobe. This method may act as a useful tool for studying the mechanisms underlying cooperation of brain regions in cognitive processes.
    Keywords: Coherence; Wavelet Coherence; Monte Carlo; General-purpose Computing on the Graphics Processing Unit; ERP; Visual-auditory; Neural network

Special Issue on: "Application-oriented Protocol Design for Wireless Ad Hoc Networks"

  • A New Multimedia-Oriented Architecture and Protocol for Wireless Ad Hoc Networks   Order a copy of this article
    by Juan Diaz, Jaime Lloret, Jose Jimenez, Mohammed Hammoumi 
    Abstract: The number of smart phones, tablets, PDAs and other type of mobile devices used regularly by the population is growing fast. They are able to offer high processing capacities while having several wireless interfaces. Wireless ad hoc networks are widely used to create spontaneous ad hoc networks in order to share resources between users. In this paper, we propose a new multimedia-oriented application layer protocol. It takes into account the multimedia services offered by the nodes in the wireless ad hoc network in order to select the best multimedia service provider node and to provide the best QoE and QoS to the nodes participating in the ad hoc network. We will show the designed protocol and decision algorithms in order to provide the best multimedia service to the end users. The study case shown in the paper and the gathered measurements validate the proposed system.
    Keywords: Multimedia Protocol, Wireless Ad Hoc Networks, MANET
  • An Autonomous Redeployment Algorithm for Line Barrier Coverage of Mobile Sensor Networks   Order a copy of this article
    by Jie Jia, Xueli Wu, Jian Chen, Xingwei Wang 
    Abstract: Redistributing mobile sensor nodes to provide guaranteed barrier coverage is critical for many sensor networks applications such as intrusion detection and border surveillance. In this paper, we study the problem of sensor redistribution for mobile sensors to achieve line-based barrier coverage. We first give the formulation of the theoretical analysis on what is optimal sensor layout with the given random deployment. Then, a fully distributed sensor redistribution algorithm to achieve line-based barrier coverage is proposed for mobile sensor networks. We formally prove that our algorithm can reach a final stable deployment and barrier coverage in a finite time. Extensive simulations are conducted to verify the validity of our analysis for mobile wireless sensor networks.
    Keywords: mobile sensor network; autonomous redeployment; barrier coverage; moving distance
  • LARES: Latency-Reduced Neighbor Discovery for Contagious Diseases Prevention   Order a copy of this article
    by Wei Liu, Hong Li, Yongle Chen, Hongsong Zhu, Limin Sun 
    Abstract: Contagious diseases threat seriously to human health and even more to the whole society. One of the most effective way to control their spread is to isolate the infected patients and their contacts. But in practice, it is quite challenging to target the contacts. Nowadays, the popularity of smart phones provides an efficient solution to record the contact information. The contact recording problem can be formulated as a low power asynchronous neighbor discovery problem. Traditional neighbor discovery protocols are not suitable for our application, due to their inadequate consideration for high mobility and crowd density-latency relationship. In this paper, we propose LARES, a group based cooperative neighbor discovery protocol. LARES reduces the discovery latency by selecting appropriate phase difference combination to detect neighbors by group. Evaluation results show that LARES can dramatically reduce the discovery latency.When using 10% duty cycle, the expected and the worst case latency are about 1/20 of Disco in single neighbor discovery scenario. The average total latency to discover all the neighbors in an area is only 1/3 of Disco.
    Keywords: Infectious Disease Prevention, Neighbor Discovery, Group Cooperation, Optimal Phase Difference Selection.
  • Congestion Avoidance Routing for MANETs   Order a copy of this article
    by Yao Hua Ho, Meng Chang Chen, Han-Chieh Chao 
    Abstract: In a Mobile Ad Hoc Network (MANET), communication connections need to adapt to frequent and unpredictable topology changes due to the mobility, energy constraints, and limited computing power of the mobile hosts. Early solutions address this fundamental requirement by employing techniques that can reconnect a broken link quickly with a low overhead; however, this strategy cannot cope with the increased frequency of broken links in a high mobility environment. To resolve the problem, greedy techniques (i.e., packet switching or geographic routing) have emerged. The scheme rely on any mobile hosts along the general direction towards the destination node to help forward data packets. However, the greedy approach suffers from packet loss because the packet forwarding policy does not consider traffic congestion along the route or the direction. In this paper, we propose a congestion avoidance routing (CAR) technique for two greedy protocols, Connectionless Approach (CLA) and Contention-based Forwarding (CBF), to address the packet loss problem by rerouting packets dynamically to avoid traffic congestion. To demonstrate the improvement of the proposed techniques, we studied and showed the simulation results on not only different metrics (i.e., packet delivery, end-to-end delay, control overhead, and energy consumption) but also different network environments/settings (i.e., real-world road network, congestion metric, and size of contention area). The extensive performance results show that the proposed techniques outperform existing approaches.
    Keywords: Communication connection; congestion avoidance; mobile ad hoc networks; routing protocol.
  • Modeling Energy Efficiency of OR Protocols in Wireless Networks   Order a copy of this article
    by Arka Prokash Mazumdar, Anandghan Waghmare, Ashok Singh Sairam 
    Abstract: Although opportunistic routing (OR) for ad hoc networks have been shown to improve network throughput, energy audit of these protocols have not been done. In this paper, an analytical model to characterize the energy consumption of OR protocols is presented. Total energy consumption is computed taking into account the energy consumed in exchanging control packets, data packet transmission including retransmission and reception. The model considers packet retransmissions that can occur due to network conditions and protocol inaccuracies. The proposed analytical model is used to compute the energy consumption of some well known OR protocols available in literature. The result of the mathematical model is compared with simulation results. The theoretical and experimental results are found to be in conformance.
    Keywords: energy analysis, opportunistic routing, wireless ad hoc networks, network lifetime
  • A Comprehensive Analysis of Association Process for IEEE 802.15.4 Wireless Networks   Order a copy of this article
    by Jo Woon Chong, Dan Keun Sung, Yunyoung Nam 
    Abstract: In this paper, we analyze the association procedure of IEEE 802.15.4 ZigBee devices and propose an efficient association algorithm which associate ZigBee devices with a piconet coordinator (PNC) with changing CSMA/CA MAC parameters adaptively to the number of unassociated ZigBee devices. The proposed analysis model is based on Markov chain and order statistics concepts and the proposed association algorithm is based on a dynamic estimation concept. As a performance measure, total association time E{Tassoc} of ZigBee devices is considered. Moreover, the maximum number Nmax of ZigBee devices, with which pre-given association time requirement is satisfied, is also investigated. Simultaneously association request from ZigBee devices enlarge E{Tassoc} due to increased collisions of association request and data request commands. The proposed association algorithm predicts the number of unassociated devices by measuring congestion and allocates the optimal MAC parameter values for unassociated devices to use them. Numerical results show that analytical results match well with simulation results and the proposed association algorithm shortens total association time compared to the conventional algorithm. A ZigBee network with the proposed association algorithm accommodates approximately 2 times more users than with the conventional one.
    Keywords: association; energy consumption; IEEE 802.15.4; performance analysis; throughput; ZigBee

Special Issue on: "BikeNet Theory, Technology and Application"

  • A wireless navigation and healthcare system for Group Recreational Cycling   Order a copy of this article
    by Kun-Ming Yu, Chi-Chung Lee, Hung-Nien Hsieh, Hsin-Wen Chang, Jiayi Zhou, Cheng-Yan Yu, Jian-Yuan Liu, Ming-Gong Lee 
    Abstract: Group recreational cycling (GRC) is a new kind of tourism activity involving a courier and a number of tourists. In addition to cyclists safety and comfort, tracking their position, monitoring their health condition in terms of heart rate, guiding and warning along the way if necessary, are important in GRC. Information exchange among cyclists is essential to achieve above goals. In this paper, an event-based wireless navigation and healthcare system (EWS) for group recreational cycling (GRC) using an Ad Hoc network with multi-hop protocol to transmit data among devices is proposed. EWS can be implemented to design suitable routes, to warn about bad road conditions, to play multimedia attractions for guiding, track cyclists position and to monitor members heart rate. System structure and design for EWS are given. Two scenarios are shown to demonstrate and to show the feasibility of EWS.
    Keywords: Group recreational cycling, Ad Hoc network, Multi-hop, Event-based wireless navigation and healthcare system, Route planning, Healthcare
  • Implementing a Green Bicycle Alliance Using a Wireless Sensor Network   Order a copy of this article
    by Haw-Yun Shin, Chung-Ming Own 
    Abstract: Cycling not only relieves every day stress but also benefits peoples mental and physical health and reduces increasingly severe greenhouse effects. Wireless sensor networks (WSNs) are applicable for immediate sensing and wireless remote monitoring because their characteristics and advantages include low power consumption, simple construction, and great expandability. In this study, we used the wireless sensor network technique to design the following three modules: a bike device module, bike path establishment module, and cloud service module. These three modules were used to address issues related to cycling activities, including green power supply, activity and health records, trajectory monitoring and group positioning, and immediate safety issues. The bike device module installs each bicycle with a green power source that provides independent power. The bicycles are equipped with a unique WSN identification device and an optional biomedical monitoring device. GPS is not required, and when cyclists cycle on paths provided by the bike path establishment module and use the cloud service module, the previously mentioned issues are addressed. Furthermore, the cloud service module includes a path establishment simulation system that enables a path manager to simulate paths before they are physically provided to determine the ideal establishment method for providing wireless sensor nodes. In this study, we used the Danshui Golden Waterfront in northern Taiwan and a bicycle path of approximately 13 km to implement on-site establishment and installation.
    Keywords: Wireless sensor networks (WSNs), energy saving, environmental monitoring, trajectory tracking
  • SOS: A Secure Social-aware Credit-based Stimulating Mechanism for BikeNet   Order a copy of this article
    by Guowei Wu, Jia Wang, Lin Yao, Chi Lin 
    Abstract: BikeNet is a class of mobile sensing system for cyclist characterized by limited bandwidth capacity, small size and high mobility. Thus, the data propagation process follows opportunistic sensor networking principles and techniques. However, as the mobile devices embedded in the bicycle are managed by rational individuals, the selfish behaviors that attempt to conserve their resources can significantly degrade the network performance. In this paper, a secure social-aware credit-based stimulating mechanism for BikeNet is proposed to encourage the cooperation among nodes while resisting the malicious attacks. The social context information is utilized to formulate the routing and data forwarding strategy. Moreover, to guarantee the security of nodes and enhance the confidentiality and integrity of messages, we propose identity based cryptosystems based on social attributes for BikeNet. Security analysis and performance evaluation demonstrate that SOS can effectively stimulate the cooperation of nodes while keeping the confidentiality and integrity of messages.
    Keywords: BikeNet; social awareness; selfish node; security; stimulating mechanism.
  • Solving Station Decision Problem in Bicycle Ad Hoc Networks   Order a copy of this article
    by Wen Ouyang, Chang Wu Yu, Kun-Ming Yu, Ko-Jui Lin, Hsin-Wen Chang, Hung-Nien Hsieh, Lin-Li Tai, Chung-Han Lin 
    Abstract: The sport of biking has gained in popularity recently, causing public bicycle systems to have been adopted in many cities and communities around the world. However, developing and designing a successful public bicycle system is challenging. This work proposes a novel problem called Station Decision Problem for Bicycle Ad Hoc Networks. The problem is to find the minimum number of bike stations while first satisfying reachability and richness conditions. After that, practical geographic concerns such as unreachable areas and maximum distances are considered. Station decision algorithms are provided with simulations conducted to demonstrate the effectiveness of the methods. A real site data is also plugged in to show the result of the station decision algorithms.
    Keywords: Station Decision Problem; Bicycle Ad Hoc Networks; Location Allocation; Public Bicycle Systems; reachability; richness
  • A location-based context-aware service discovery approach for cycling experience   Order a copy of this article
    by Duen-Kai Chen, Feng-Cheng Chang, Szu-Yin Lin 
    Abstract: This study explored the use of context-aware information to facilitate web service composition in ubiquitous computing setting. Consumer electronics and Internet access which enable ubiquitous computing have played an essential part in our daily life, even for bike riding experience. Future applications for cyclists will consequently be required to interact with multiple, specialized services. In this study, an SOA-based service discovery and invocation framework that is realized using the XMPP technology is proposed and the framework design is presented. An example of restaurant recommendation system is presented, as a proof of concept prototype, to demonstrate and investigate the feasibility and effectiveness of the proposed framework.
    Keywords: ubiquitous computing, location-based service, service discovery, context-aware recommendation system.
  • An Efficient Cloud-Assisted Best-Parking Algorithm for BikeNet   Order a copy of this article
    by Hong-Yi Chang, Shih-Chang Huang, Yuan-Wei Lin 
    Abstract: Numerous countries have implemented public bike policies. Users can rent a bike in one place, and return it at a different location. However, users that change to another type of transport may spend considerable time searching for a parking space for the bike. This study proposes an efficient best-parking (BP) algorithm for bike networks. This mechanism efficiently offers bike users route with parking spaces nearby destination. This study also presents a parallel BP algorithm based on the MapReduce model to accelerate the computation of the ideal route for parking. Simulation results show that the performance of the proposed algorithm is approximately 70% better than that of the aggregating data dissemination (ADD) algorithm and 91% better than that of the parking space discovery (PSD) algorithm. The proposed BP algorithm collects parking-space information only as needed. Therefore, the BP communication overhead is considerably lower than that of ADD or PSD algorithms.
    Keywords: BikeNet; Bike Networks; Cloud Computing; MapReduce; Best Parking.

Special Issue on: "Security Aspects in Pervasive and Ubiquitous Computing"

  • A new handover authentication protocol based on bilinear pairing functions for wireless networks   Order a copy of this article
    by Debiao He, Muhammad Khurram Khan, Neeraj Kumar 
    Abstract: Seamless handover over multiple access points is highly desirable to mobile nodes, but ensuring security and efficiency of this process is challenging. Many such protocols have been proposed but most of them are either insecure or inefficient. Very recently, He et al. proposed an improved protocol to overcome the weakness of a novel handover authentication protocol named PairHand. Later, they pointed out that their protocol is vulnerable to a private key compromised problem under certain circumstances and proposed an improved protocol to overcome the weakness. In this paper, we examine the security of He et al.s improved protocol and show it is vulnerable to a private key compromised problem. To improve security, we propose a new ID-based signature protocol and construct a new handover authentication protocol based on the proposed signature protocol.
    Keywords: Wireless networks, security, privacy, efficiency, handover authentication.
  • Security Analysis and Improvement of a Mutual Authentication Scheme under Trusted Computing   Order a copy of this article
    by Fahad Muhaya 
    Abstract: Recently, Yang et al. proposed a smart card and password based mutual authentication scheme under trusted computing, and they claimed that their scheme can resist kinds of attacks. But, they did not consider the stolen smart card attack which is an important attack in smart card based authentication scheme. In this paper, we first analyses the stolen smart card attack to Yang et al.s scheme, and then proposes an enhanced mutual authentication scheme for trusted computing. Our scheme can resist the stolen smart card attack and other attacks, and can quickly detect the unauthorized login at the beginning when the user input the wrong identity or wrong password.
    Keywords: user authentication; password; smart cards; cryptanalysis; trusted computing

Special Issue on: "User Interfaces and Interaction Models in Context-based Computing"

  • A RESTFull Interface for Scalable Agents based Cloud Services   Order a copy of this article
    by Salvatore Venticinque, Luca Tasquier, Beniamino Di Martino 
    Abstract: Agent technology provides asynchronous mechanisms that could represent the best choice for effective programming of Cloud, due to the unpredictable behaviour of the network. Cloud Agency is a collection of agent based services for provisioning, monitoring and autonomic reconfiguration of Cloud resources at infrastructure level, which go beyond the common offer by commercial providers and by open Cloud technologies. Its service interface provides methods for orchestrated executions of agents that implement a scalable solution for provisioning and management of Cloud resources at infrastructures level. Cloud Agency extends the Open Cloud Computing Interface (OCCI) proposal of standard. We present the design of Cloud Agency Interface and the implementation of an RESTfull to/from ACL gateway that allows for the communication between the Cloud world and the agents' one, being compliant with OCCI and extending its model and services. We investigate performance and scalability of the proposed solution.
    Keywords: Cloud, IAAS, Agents, Service Brokering, Resource Provisioning, OCCI
  • Exploration of Head Gesture Control for Hearing Instruments   Order a copy of this article
    by Bernd Tessendorf, Peter Derleth, Manuela Feilner, Franz Gravenhorst, Daniel Roggen, Thomas Stiefmeier, Christina Strohrmann, Gerhard Troester 
    Abstract: In this work, we investigated the benefit of head gestures as a user interface to control hearing instruments (HIs). We developed a prototype of a head-gesture-controlled HI, which was based on a customized wireless acceleration sensor for unconstrained and continuous real-time monitoring of the users head movements. We evaluated the system from a technical point of view and achieved a precision of 96% and a recall of 97% for spotting the two head gestures used: tilting the head to the left and right side. We further evaluated the system from the users point of view based on the feedback from 6 hearing-impaired HI users (4 men, 2 women, age 27-60). We compared our head-gesture-based control to existing HI user interfaces: HI-integrated buttons and HI remote control. We found that the benefit of the different HI interaction solutions depends on the users current situations and that all participating HI users would appreciate head gesture control as an additional, complementing user interface.
    Keywords: multimodal hearing instrument; head gesture control; user interface; recognition algorithm; body-worn sensors, ubiquitous computing.
  • An Overview of Energy Savings Potentials Through Mobile Forwarding Proxy Framework   Order a copy of this article
    by Patrick Seeling 
    Abstract: Increasingly, mobile users interact with more than their primary mobile device, a trend that will likely continue with the growth of the Internet of Things. We introduce an application data forwarding framework, which is based on a mobile user's primary device and geared towards energy savings for the multitude of devices a mobile user interacts with. Based on the need to have a recent copy of application data available on a mobile user's primary device, e.g., a smartphone, our framework forwards, e.g., Facebook status updates, to external devices in vicinity. We provide an evaluation of the energy consumption and potentials for savings using our proposed approach by means of cost-based evaluations. Assuming that external devices could derive the data through cellular or wireless LAN connections as alternatives, we find that significant savings for the group of devices could be realized. Specifically, for an active social network account with frequent updates, we find that the external devices would be able to conserve power, while the additional burden on the primary device's battery remains reasonably low.
    Keywords: Mobile communication, Cross layer design, Web services, Context-aware services
  • Dynamic Safe Regions for Moving Range Queries in Mobile Navigation   Order a copy of this article
    by Haidar AL-Khalidi, David Taniar, John Betts, Sultan Alamri 
    Abstract: The cost of monitoring and updating the location of Moving Queries is very high, as the calculation of a range query needs to be re-evaluated whenever the query moves. Many methods have been proposed to minimise the computation and the communication costs of continuously monitoring Moving Range Queries. However, these have only partially solved this problem by attempting to reduce the number of communications between query and server whilst using the traditional search approach of polling all possible objects. In response, we propose an efficient technique by adopting the concept of safe region. Safe region is an area where the set of interest objects of the query does not change while the query remains inside it. There is no need to update the moving queries while they are roaming within their safe regions. This paper presents a technique which is the first of its kind to create a continuous Basic Safe Region by calculating the closest objects to the border of the moving query. This paper also introduces a continuous Extended Safe Region by calculating the intersections among several range objects. We compare the size of the safe regions obtained using these two techniques. The experimental results indicate that as long as the query remains in its specified safe region, expensive re-computation is not required, thereby reducing computations and communications cost in client-server architectures.
    Keywords: Safe region; Moving range query; Query processing; Mobile navigation
  • Internet-of-Things: why we arent there yet   Order a copy of this article
    by Salvatore Sorce, Antonio Gentile 
    Abstract: Twenty-one years past the Weisers vision of Ubiquitous Computing, and it is yet to be fully fulfilled, despite of almost all the needed technology is already available. The widespread interest in UbiComp and the results in some of its fields, pose a question: why we arent there yet? It seems we miss the octopus head. In this paper we will try to depict the reasons why we are not there yet, from three different points of view: interaction media, device integration, and applications.
    Keywords: Ubiquitous computing, pervasive systems, interoperability, interaction media, device integration, Human-Environment Interaction
  • Smart Care Spaces: Pervasive Sensing Technologies for At-Home Care   Order a copy of this article
    by Andrew Thomas, Cain Evans, Philip Moore, Hanifa Shah, Mak Sharma, Sarah Mount, Fatos Xhafa, Hai Pham, Asma Patel, Anthony Wilcox, Craig Chapman, Parmjit Chima 
    Abstract: Society is experiencing an ageing demographic, coupled with increasing prevalence of Alzheimer's and Dementia conditions, expected to cause explosive increases in healthcare costs. Therefore, there is currently a need to develop pervasive technologies that allow monitoring of patients at home, where medically permissible, in order to reduce pressures on formal healthcare spaces. Those 'smart care spaces' require use of sensors and intelligent computer systems in order to support the needs of the cared-for, carers and medical personnel. In so doing they can ensure quality-of-life through comfort and adequate medical-monitoring, as well as providing significant data for on-going medical evaluation and diagnosis. This requires two main elements of sensing: sensors to monitor the care environment and patient-mounted sensors to monitor physiological parameters. Therefore, this paper considers technological options available for such monitoring and provides examples of their use. It will be concluded that cost-effective solutions are available for development of smart care space monitoring, to help ensure that associated computer systems maintain an appropriate level of intelligence.
    Keywords: Smart care spaces, e-health, sensors, aging, dementia, care, ad-hoc, ubiquitous.