International Journal of Sensor Networks (24 papers in press)

Regular Issues

• Recent Advances in Wireless Sensor Networks with Environmental Energy Harvesting
  by Lei Shu, Wanjiun Liao, Jaime Lloret, Lei Wang 
  Keywords: .
  
  
• Fixed Node Assisted Collection Tree Protocol for Mobile Wireless Sensor Networks  
  by Ramiro Liscano, Nadra Ben Otman, Shahram Shah Heydari, Dixit Sharma 
  Abstract: The Collection Tree Protocol (CTP) is widely used for data collection in static wireless sensor network applications. With the increasing deployment of mobile wireless sensor networks, the performance of this scheme in mobile scenarios becomes extremely important. The motivation in using collector style protocols in mobile sensor networks is that the sensors primarily send data to key collecting nodes, and often there is no need for more complex Mobile and Ad hoc routing protocols. We introduce the Fixed Node Assisted-CTP (FNA-CTP) which aims to enhance the performance of CTP in mobile scenarios by tuning the parameters of CTP for the mobile and fixed nodes in order to reduce the messaging overhead required to maintain the network in mobile scenarios. We provide a detailed evaluation of the performance of FNA-CTP in different mobile sensor network scenarios through a set of simulations which indicates the superior performance of FNA-CTP and discuss various design issues associated with this scheme.
  Keywords: Collection Tree Protocol (CTP); Mobile Wireless Sensor Networks; Wireless Sensor Networks (WSN).
  
  
• A New Model and Algorithm for RSA Problem in Elastic Optical Networks  
  by Chunxia Ji, Yuping Wang, Xia Li 
  Abstract: Routing and Spectrum Allocation(RSA) is an important problem in elastic optical networks(EONs). With the increase of network scale and task requests, the imbalance of the network topology becomes more and more prominent, causing congestion of some links in the network and even paralyzation of the entire network. To tackle this issue, in this paper, we first set up an integer linear programming model for RSA problems in EONs, which minimizes the number of used slots, optimizes the balance of networks and the burden of KeyLinks (i.e., the links which are easy blocked when large requests comes). Then we design a new routing scheme called Dynamically Adjusted Shortest Hop Count and Minimum Rank Value First(DSHMRF) to select the candidate routes for each request. Moreover, we propose a new genetic algorithm called Direction and Distance- Based Genetic Algorithm(DDGA) to look for optimal routes for all requests among the candidate routes. To allocate the spectrum reasonably, we adopt First Fit (FF) scheme. Finally, the experiments are conducted on several network topologies of different scales with different request sets and the results indicate that the proposed model effective and the proposed genetic algorithm is efficient.
  Keywords: elastic optical network; routing and spectrum allocation; integer linear programming model; genetic algorithm.
  
  
• SPRP: A SECURED ROUTING PROTOCOL FOR DELAY TOLERANT NETWORKS  
  by Swati Bansal, JAGTAR SINGH SIVIA, HARMINDER SINGH BINDRA 
  Abstract: A Delay Tolerant Network (DTN) depends on certain assumptions that nodes cooperate and coordinate towards message forwarding. However, this assumption can't be satisfied if there are malicious nodes in the network these malicious nodes intentionally attract and drop messages from other nodes of the network. In this paper we propose a scheme for preventing malicious nodes from launching the combination of Routing Misrepresentation and Sybil attacks. This scheme is based on identity based digital signature scheme. Each node in a network needs to verify its identity before taking an interest in the message exchange process. The proposed system is utilized to Secured Prophet Routing Protocol (SPRP) against the combination of Routing Misrepresentation and Sybil attacks. The resulting protocol is robust against these combinations of attacks.
  Keywords: Delay Tolerant Network; Routing Protocol; Prophet; Attacks; Delivery Probability; Overhead Ratio; Average Buffertime; Average Latency; Identity Based Digital Signature Technique.
  
  
• Accelerometer based quantitative outcome measurement for hand function test  
  by Aneesha Acharya K, Somashekara Bhat, Kanthi M 
  Abstract: Hand Function test gives relationship between functional limitations in activities and performance components such as Range Of Motion and strength. Physicians assess the degree of impairment in the upper extremity based on the time taken to complete the tasks. This paper proposes a hand function test which incorporates sensor on the object. The quantitative parameters such as time and acceleration with which task is completed are measured. Accelerometer data is sensitive to the movement of the body and gives variety of movement patterns during task performance. Light Dependent Resistor (LDR) provides important movement queues, such as initialization and completion of the selected activity. As sensors are embedded on the object, there is a scope for free movement of upper extremity during performance of test. Auto-time calculation during test session certainly reduces the clinician intervention time. Clinician can give more emphasis on functional movement of hand rather than spending time in documentation. The field of application of this tool are in physiotherapy and occupational therapy.
  Keywords: Hand function test; upper extremity; outcome measurement; Light Dependent Resistor; accelerometer; ultrasonic sensor; Bluetooth.
  
  
• Relay Node Deployment for Wireless Sensor Networks using Evolutionary Multi-objective Algorithm  
  by Qiang Wang, Hai-Lin Liu, Fangqing Gu 
  Abstract: In this paper, we study the relay node placement problem of, given a deployment of sensor nodes, finding the minimum number of relay nodes to increase the lifetime and reduce the deployment costs of WSNs simultaneously. In particular, we use the average remaining energy of the relay nodes to express the lifetimes of the WSNs. Due to the conflict of the average remaining time and deployment costs of relay nodes, we first formulate the relay node placement problem as a multi-objective optimization problem, which is difficult to address using traditional methods. Based on this, a novel evolutionary multi-objective algorithm is presented to solve the problem. Furthermore, a local search method is presented to improve the convergence of the algorithm. Simulation results show that the proposed relay node placement scheme can efficiently reduce the cost and increase the lifetime.
  Keywords: Cost; Relay node placement; Connectivity; lifetime; Wireless Sensor Networks; Evolutionary algorithm.
  
  
• CITT - Construction of an Interference-Tolerant Tree Topology using Cross-Layer Information.  
  by Sergio Diaz, Diego Mendez 
  Abstract: WSNs operate on unlicensed frequency bands that are shared with other technologies, such as WiFi and Bluetooth. Under these circumstances, the wireless channels suffer from interference problems that result in unreliable communications. To cope with this problem, we propose a mechanism that builds and maintains a tree topology, which estimates the level of interference on the wireless channel and takes routing decisions accordingly. We call our mechanism Construction of an Interference-Tolerant Tree topology (CITT) and divide it into three steps: information collection, fault detection and fault recovery. In the first step, CITT gathers data related to the interference from the MAC layer. In the second step, CITT estimates the level of interference on the wireless channel by using a naive Bayes classifier. In the third step, CITT finds the routing paths with the lowest levels of interference. We implemented CITT on Contiki and evaluated it on a real testbed composed of 10 nodes. The results show that CITT outperforms RPL regarding end-to-end latency and packet reception rate, at the cost of a slight increase in power consumption.
  Keywords: Interference problem; Tree construction; Tree maintenance.
  
  
• Clustered Heterogeneous Wireless Sensor Network Infrastructure for reliable and efficient Path Planning of Mobile nodes in Remote Area  
  by Pankaj Pal, Sachin Tripathi, Chiranjeev Kumar 
  Abstract: Remote area coverage by employing a mix of mobile and stationary sensors is a reliable and cost-effective approach. Path planning decision by mobile node deployed in a remote environment depends on information gathered from its surrounding. Since the decisions are made locally there is no global awareness of path trajectory among mobile nodes, resulting in path overlapping and uneven load balancing due to long distance traversals. This proposal presents a path planning approach that divides the target environment into clusters of equal coverage hole densities using $K-mean^{++}$ algorithm. Thereafter, mobile nodes are assigned to these clusters and are confined to detect and cover holes within their cluster. The effectiveness of cluster formation is measured using Multiple co-relational analysis, and then the variance of effectiveness is performed over different cluster formation to select the optimum cluster count. Restriction of the mobile node in different regions (cluster) of target area avoid overlapping of path trajectories and provide load balancing among nodes. Comparison with the previous state-of-the-art techniques demonstrates that the proposed work provide high coverage with limited movement.
  Keywords: Wireless sensor network; mobile sensor; path planning; clustering; coverage hole.
  
  
• Virtual Backbone Construction for Large-Scale Ad Hoc UAV Networks  
  by Hai Yu, Qin Liu, Hejiao Huang, Xiaohua Jia 
  Abstract: Unmanned aerial vehicles (UAVs) technology has attracted great attention in recent years, and it has a wide range of applications. The communication among UAVs is a critical issue to support these applications. However, most of the existing routing algorithms are not suitable for UAV networks. In this paper, we propose a distributed virtual backbone construction algorithm for UAV networks. We also propose a distributed protocol to dynamically maintain this communication backbone. Our algorithm is purely distributed and scalable, as we only use the neighbour information of UAVs. We also utilize the over-heard messages broadcast by the neighbouring UAVs to construct the virtual backbone efficiently to interconnect all cluster heads (CHs). Our virtual backbone construction algorithm is efficient in terms of number of messages broadcast by each UAV and the completion time of the backbone construction. Simulation results also demonstrated that our proposed algorithm is efficient and effective.
  Keywords: Mobile ad hoc network; UAV; virtual backbone; clustering; routing.
  
  
• Implementation of Compressive Sampling for Wireless Sensor Network Applications  
  by Nathan Ruprecht, Xinrong Li 
  Abstract: Since mid-20th century, we have accepted the Nyquist-Shannon Sampling Theorem in that we need to sample a signal at twice the max frequency component in order to reconstruct it. Compressive Sampling (CS) offers a possible solution of sampling sub-Nyquist and reconstructing using convex programming techniques. There has been significant advancements in CS research and development (more notably since mid-2000s), but still nothing to the advantage of everyday use. Not for lack of theoretical use and mathematical proof, but because of very limited implementation work. There has been little work on hardware in finding the realistic constraints of a working CS system used for digital signal processing (DSP) applications. Any parameters used in a system are usually assumed based on stochastic models, but not optimized towards a specific application. This paper aims to address a minimal viable platform to implement compressive sensing if applied to a wireless sensor network (WSN) system, as well as addressing a number of key parameters of CS algorithms to be determined depending on practical application requirements and constraints.
  Keywords: Compressive Sensing; Compressive Sampling; Wireless Sensor Network.
  
  
• Design, Implementation and Analysis of Routing Based Attack Model for Delay Tolerant Networks with Prophet Routing Protocol  
  by Swati Bansal, Jagtar Singh Sivia, Harminder Singh Bindra 
  Abstract: Delay tolerant network (DTN) is an evolution of Mobile Adhoc Network (MANET). It is an emerging area in the field of networking. As the technology of computer networks is developing rapidly, DTN require more security. In computing, network security is the main issue as the attacks by malicious and selfish nodes are increasing on the network day by day. This paper defines an attack model in which malicious nodes (in DTN with Prophet Routing Protocol) receive the data from genuine nodes. It is done by falsifying their routing information (delivery predictability). Later malicious nodes spoof their identity and receive message as destination nodes. Legitimate messages from the network are deleted by malicious nodes. The messages are also deleted from the source node buffer as the source node treats the message being delivered to the final destination. Delivery Probability, Overhead Ratio, Average Latency and Average Buffer time metrics are evaluated and analyzed using ONE simulator. In simulated network, 125 nodes are considered and by making only 3 % nodes (four) malicious, performance of the network is decreased by approximately 40 % to 50 %.
  Keywords: Delay Tolerant Network; routing Protocol; Prophet; Attacks; Delivery Probability; Overhead Ratio; Average Buffertime; Average Latency.
  
  
• Diffusion Improved Multiband-Structured Subband Adaptive Filter Algorithms with Dynamic Selection of Regressors and Subbands Over Distributed Networks  
  by Mohammad Shams Esfand Abadi 
  Abstract: The present study solves the problem of distributed estimation in the diffusion networks based on the family of improved multiband-structured subband adaptive filters (IMSAFs). The diffusion IMSAF (DIMSAF), the DIMSAF with dynamic selection of regressors (DIMSAF-DSR), and the DIMSAF with dynamic selection of subbands (DIMSAF-DSS) are established. The DIMSAF has faster convergence speed than diffusion normalized subband adaptive filter (DNSAF) algorithm, especially for colored Gaussian input of the nodes. The DIMSAF-DSS and the DIMSAF-DSR algorithms, while benefiting from high convergence speed in DIMSAF, have lower computational complexity and lower steady-state error. During the weight coefficients adaptation in DIMSAF-DSR, the input signal regressors are dynamically selected at each subband of different nodes. In DIMSAF-DSS, the subbands are dynamically selected at each node. In the following, the introduced algorithms are established based on a general update equation. Accordingly, the mean-square performance analysis of the algorithms is studied in a unified way and theoretical relations for learning curve and steady-state error are derived for the entire network. The theoretical results and the good performance of proposed algorithms are justified by several computer simulations in adaptive diffusion networks.
  Keywords: Diffusion network; distributed estimation; dynamic selection; improved multiband-structured subband adaptive filter; mean-square performance.
  
  
• Centroid determination hardware algorithm for star trackers  
  by Gabriel Mariano Marcelino, Victor Hugo Schulz, Laio Oriel Seman, Eduardo Bezerra 
  Abstract: The execution of centroid extraction algorithms using a microprocessor consumes considerable resources when compared to the other steps involved in star trackers. This paper presents a method to identify star centroids in star trackers by pre-processing the pixels using an FPGA directly in the stream transmitted by an image sensor. The dedicated hardware filters the star pixels and transmits them to a processor, which computes the centroids of the respective image using an infinite impulse response filter. Thus, there is a substantial decrease in memory consumption and a reduction of the processor usage during the attitude determination computation, making the process more attractive for small satellites. A hardware-in-the-loop simulation is presented to test the performance of the system. It was possible to achieve a subpixel precision in the centroid coordinates' estimation, and also lower execution times in comparison with methods based on the processing of whole images.
  Keywords: Embedded Systems; Nanosatellites; Attitude Determination; Star Trackers; Centroid Determination; FPGA.
  
  
• Low-Cost Localization Considering LOS/NLOS Impacts in Challenging Indoor Environments  
  by Vahideh Moghtadaiee, Nasim Alikhani, Seyed Ali Ghorashi 
  Abstract: One popular localization method in Wireless Sensor Networks (WSN) and Wireless Local Area Networks (WLAN) is fingerprinting technique, in which Received Signal Strength (RSS) values are measured by smart-phone internal sensors at some Reference Points (RPs) and stored in a radio map. However, constructing the radio map is time-consuming and labor-intensive. In this paper, we propose a novel method to decrease the training cost by building a simulated radio map using an improved path-loss model in which the impacts of Line of Sight (LOS) and Non-Light-of-Sight (NLOS) propagations are taken into account. Including LOS/NLOS effects also improves distance estimation. Furthermore, the simulated radio map helps assess and improve the fingerprinting area and network parameters prior to the actual positioning. For performance evaluation, three kinds of radio maps are created using simulation and a test field experiment and then compared based on deterministic and probabilistic algorithms. The results indicate that the improved model outperforms the typical path-loss model and the localization error gets closer to the actual error of the fingerprinting network.
  Keywords: Indoor localization; Fingerprinting; Received Signal Strength (RSS); LOS; NLOS.
  
  
• Using Neural Networks to Reduce Sensor Cluster Interferences and Power Consumption in Smart Cities  
  by Per Lynggaard 
  Abstract: In the future smart cities, billions of communicating IoT devices are expected which communicate wirelessly in the limited spectrum offered by 5G and long-range technologies. This means that a huge amount of interferences must be overcome by new agile technologies without wasting power resources in the IoT nodes. In this paper, these challenges are addressed by a neural-network-based machine learning system that is based on frequency-domain features extracted from the communication channel. This machine learning system predicts the needed transmit power to overcome the interferences by a predefined margin. Extensive system simulations have been performed on a real-world dataset that shows power savings in the range of 35 to 83 percent and a packet receive-ratio of at least 95 percent. Similarly, it has been found that the system converts after approximately 50 supervised samples, which supports efficient tracking of parameter variations in the communication channel.
  Keywords: Smart buildings; IoT networks; interferences; neural-networks; transmit-power regulation; decentralized control schemes.
  
  
• A Key Management Scheme Realizing Location Privacy Protection for Heterogeneous Wireless Sensor Networks  
  by Erdong Yuan, Liejun Wang 
  Abstract: Key management is the core of wireless sensor network security management technology. At present, the protection of the source location information of nodes has also received great attention. In this paper, we combine identity-based encryption (IBE) algorithm with Elliptic curve cryptography (ECC) based digital signature authentication to achieve more secure authentication. Then we use the double encryption method to realize the location privacy protection. Finally, we adopt a new routing update scheme to prevent attackers from initiating sinkhole attacks. In addition, we add timestamps to messages transmitted between nodes to defend against resend attacks. The scheme we proposed occupies a small amount of key storage space, consumes relatively more energy to protect the location information of nodes in the heterogeneous sensor network (HSN), and prevents attackers from initiating sinkhole attacks and resend attacks, thereby enhancing network security.
  Keywords: Key management; Location privacy protection; Sinkhole attacks; IBE algorithm; HSN.
  
  
• Cost-effective Routing as a Service (RaaS) in Sensor-Cloud  
  by BIPLAB SEN, Anupam Sarkar, Sunimal Khatua, Rajib Das 
  Abstract: Sensor-cloud is a collaborative platform which allows multiple Wireless Sensor Networks (WSN) to pull their resources together for better utilisation and efficiency. In this work, we consider a set of applications, each characterised by the set of targets it intends to cover and our aim is to provide Routing as a Service to all these applications in the Sensor-cloud. Each application is served by a virtual sensor network that may span multiple WSNs. We should be able to run data gathering for each application parallelly with the minimum use of Sensor-cloud resources. This is achieved by creating a collection of data gathering trees, each rooted at a different base station. We have proposed an algorithm where a minimal set of sensors are selected to cover the required targets and a spanning forest connecting them is obtained so that total energy cost of all the trees in the forest is minimized. Then we show that by applying a sequence of alterations, the cost can be further reduced. Experimental results demonstrate the advantages of serving the applications by a Sensor-cloud over standalone WSNs in terms of the usage of resources (active sensor nodes as well as energy cost per round).
  Keywords: Sensor-cloud; Wireless Sensor Network; Virtualization; Data gathering; Routing-as-a-Service.
  
  
• A MQTT-API-Compatible IoT Security-Enhanced Platform  
  by Hung-Yu Chien, Yi-Jui Chen, Guo-Hao Qiu, Jian Fu Liao, Ruo-Wei Hung, Pei-Chih Lin, Xi-An Kou, Mao-Lun Chiang, Chunhua Su 
  Abstract: Owing to its lightweight and easiness, the Message Queue Telemetry Transport (MQTT) has become one of the most popular communication protocols in the Internet-of-Things (IoT) and in the Machine-To-Machine (M2M) communications. However, the security supports in the MQTT are very weak, and the gap between the supported functions and the desirable security functions raises a big security threat to these deployments. In this paper, we systematically examine the security requirements of a MQTT-based IoT system, identify the gap between the requirements and the supported functions, and design a security-enhanced MQTT framework that facilitates device authentication, key agreement, and policy authorization. Additionally, it is desirable that any MQTT-security enhancements should be compatible with existent MQTT Application Programming Interfaces (API). We propose a two-phase authentication approach that can smoothly integrate secure key agreement schemes with the current MQTT-API. To evaluate its effectiveness and efficiency, we integrate the classic Challenge-and-Response (CR) technology and the MQTT CONNECT API. Compared to its counterparts, the results show the merits of improved communication performance, MQTT-API compliance, and security robustness.
  Keywords: Transport Layer Issues; Security and Privacy; MQTT; Internet of Things; authentication.
  
  
• Continuous-variable quantum network coding protocol based on butterfly network model  
  by Zhiguo Qu, Zhexi Zhang, Mingming Wang, Shengyao Wu, Xiaojun Wang 
  Abstract: With the development of quantum network, the need to improve the efficiency and security of network transmission is becoming more and more obvious. It is difficult in producing and detecting single photon, while quantum continuous-variables have practical significance of improving communication, as a result this paper proposes a new continuous-variable quantum network coding protocol (CVQNC) based on the butterfly network model and the properties of quantum continuous-variables. In this paper, the hybrid channel of quantum channel and classical channel is adopted to realize the cross transmission of quantum information and classical information through the corresponding operation in the intermediate node. Considering the high cost and difficulty of the implementation of quantum channel, we take advantage of classical channel, which is in accordance with the existing network resources. The new protocol not only is conducive to the realization of quantum network, but also can reduce the communication cost of quantum network effectively. It can be seen from the throughput and fidelity analysis that this protocol has a higher throughput than discrete-variable quantum network encoding scheme and classical information network encoding scheme. The ceiling of fidelity in this protocol is 4/9. According to the analysis of simple intercept attack and spectroscope attack, it is secure for the protocol to transmit quantum information and classical information by resisting on the eavesdropping attack of the third-party effectively.
  Keywords: Continuous-Variable; Network Coding; Quantum Network Coding; Butterfly Network Model; Quantum Secure Direct Communication.
  
  
• svBLOCK: Mitigating Black Hole Attack in Low-power and Lossy Networks  
  by Sonxay Luangoudom, Duc Tran, Tuyen Nguyen, Hai Anh Tran, Giang Nguyen, Quoc Trung Ha 
  Abstract: Routing Protocol for Low power and Lossy Networks (RPL) is a novel protocol that is specifically designed for the 6LoWPAN networks. Although RPL is able to avoid loop and detect inconsistencies, this protocol is still vulnerable to a variety of internal attacks. The simplest, but most effective is the black hole, whose aim is to disrupt the optimal routing structure, and hence, downgrading the network performance. In this paper, we present a novel svBLOCK scheme to handle the black hole attack. svBLOCK is based on the SVELTE Intrusion Detection System to reconstruct the DODAG and validate the node availability. It is also equipped with mechanisms to provide authenticity over its control messages and isolate black holes from the LLN. svBLOCK is implemented in Contiki OS and is evaluated under various attack scenarios. It demonstrates to achieve 98.5% True Positive Rate at a False Negative Rate of 3.7%, while improving the Packet Delivery Rate by up to 47% with respect to the original SVELTE.
  Keywords: Internet of Things; RPL; network security; black hole attack.
  
  
• Emperor Penguin Optimized Self-Healing Strategy For WSN Based Smart Grids  
  by Korra Cheena 
  Abstract: The cooperative and inexpensive speciality of sensor networks conveys significant benefits over conventional communication strategies utilized in recent electric power schemes. Now days, smart grid technologies make use of wireless sensor network in electric power generation, transmission and distribution systems. Use of sensor network in bulk power transmission become very fame due to special behaviour of networks like simple installation, wide coverage, sensitive line monitoring and effective fault tolerance. This paper proposes Emperor Penguin Optimized Self-Healing (EPOSH) strategy for sensor network based smart grid system. Self-healing is a process of automatically detecting and correcting faulted sensor nodes to enable uninterrupted power supply in smart grid systems. In proposed work, data generated from various nodes are forward to cluster leader and routed to base station from leader node. Routing performed based on EPOSH in proposed work which greatly reduces design complexity of Self-Healing process. Because, EPOSH works in an iterative manner to detect, eliminate faulty nodes and to find optimal alterative solution for routing with faulty nodes. Proposed EPOSH for SG networks implemented in Matlab working environment and resultant performances are compared with existing works such as AEC, GHS, GA-TBR and IGRC.
  Keywords: Smart Grid; Wireless sensor network; self-healing and emperor penguin optimization.
  
  
• Broadcast-Based Routing Protocol for Smart Lighting Systems  
  by Andrea Stajkic, Chiara Buratti, Roberto Verdone 
  Abstract: In this paper we consider a smart lighting system, where sensors andrnactuators are located over lamp posts in a street, generating data to be sent to a final sink, that is a 3G gateway. According to nodes location, a linear wireless network is created, devices being deployed over a line and sending data to a final destination at the end of the line. We propose a novel efficient routing protocol for this type of networks, based on broadcast transmissions. In particular, during an initial discovery phase each node identifies its neighbours and selects its best neighbour as the one being closest to the sink, that is the farthest in the line. Data is then transmitted in broadcast, by prioritising the best neighbour selected as forwarder, in order to reduce overhead. The protocol allows data packets to reach the sink through a small number of hops and, as a consequence, to improve throughput and packet delivery probability with respect to existing solutions. The proposed protocol has been implemented on theEuWIn platform, developed in the framework of the EC-funded Network of Excellence, NEWCOM#. The protocol has been tested and compared to standard solutions, based on IEEE 802.15.4 and Zigbee. Experimental results, in terms of packet loss rate, throughput and number of hops to reach the sink, show the improvement achieved with the proposed solution with respect to the existing ones.
  Keywords: Smart Lighting Systems; Linear Wireless Networks; Broadcast-rnBased Protocol; Experimentation.
  
  
• Modelling a Smart Non-invasive Adrenaline Sensor  
  by Noha MM., Nahla F. Omran, Abdelmageid A. Ali, Fatma A. Omara 
  Abstract: Adrenaline hormone may effect on cholesterol and glucose levels in the human body which may cause different diseases such as stroke. On the other hand, numerous biomedical research relies on bio-impedance technique because it possesses a lot of features such as the ability to analyze the blood components to identify different diseases. Therefore, this study aims to measure the adrenaline level non-invasive based on bio-impedance technique using a new proposed sensor to measure the adrenaline, cholesterol and glucose levels. The proposed sensor has been interfaced with a 3D model of two electrodes which used to send the current (I) to the earlobe and measure the produced voltage (V). It is simulated by COMSOL MULTIPHYSICS 5.0, and the impedance was measured at each frequency. Then the adrenaline, cholesterol and glucose values are computed using the equations. Finally, the obtained results from the simulator and the equations show that the proposed sensor would be a better choice for designing a real non-invasive medical Sensor.
  Keywords: Sensor; Bio-impedance; Internet of Things (IoT); Non-invasive.
  
  
• Hidden Markov Model Based Rotate Vector Reducer Fault Detection Using Acoustic Emissions  
  by Haibo An, Wei Liang, Yinlong Zhang, Jindong Tan 
  Abstract: The reliable fault detection of rotate vector (RV) reducer is of paramount importance for the long-term maintenance of high-precision industrial robots. This paper proposes a Hidden Markov Model (HMM) based RV reducer fault detection using Acoustic Emission (AE) measurements. Compared with the conventional faults from the common rotating machinery (such as bearings and gears), the fault from the RV reducer is more complicated and undetectable due to its inherent inline and two-stage meshing structure. To this end, this work modifies the HMM model by taking into account not only the current observations and previous states, but also the subsequent series of observations within the posteriori probability framework. Through this way, the random and unknown disturbance, which is common in the industrial scenarios, could be suppressed. Besides, the HMM is also applied to separate the AE signal bulks within one cycle that has 39 subcycles, which is a critical step for AE signal pre-processings. The proposed method has been evaluated on our collected AE signal dataset from the RV reducer in the industrial robotic platform. The experimental results and analysis validate the effectiveness and accuracy of the RV reducer fault detection model.
  Keywords: Rotate Vector (RV) Reducer; Fault Detection; Hidden Markov Model (HMM); Acoustic Emission (AE).