International Journal of Space-Based and Situated Computing (7 papers in press)
Distance Impact on Quality of Video Streaming Services in Cloud Environments
by Amirah Alomari
Abstract: Cloud computing architecture can be viewed as two domains; one is related to the resources pool such as servers and the other related to the network which eases access and sharing of these resources. It is important to measure the quality of services offered by cloud providers. However, there are no standard measurements that can be used as benchmarks to evaluate quality of service in cloud computing. Besides that, multimedia streaming applications are most critical to QoS constraints because the necessity to be delivered in smoothly without disturbing clients. In addition, it is very difficult to ensure QoS due to multiple reasons such as providers` network conditions and the unspecified routs as well the fact that routes are changing constantly. Consequently, it becomes difficult to select the best service provider that best meets customers' needs. Nowadays, videos are extensively used in different aspects of our lives such as entertainment, education and social. Thus, there is an expected huge growth of video sharing in the future. There are important factors that affect the way of transmitting videos over the clouds such as encoding techniques and compression. In this research, we study how distance affects QoS of real time applications such as video streaming service. This study is conducted using simulation methodology and distance is specified by the propagation delay in public cloud environment. We aim to study the impact of distance on the quality of video streaming services based on response time, packet end to end delay, and throughput. The results of this study show that distance has significant impact on response time and packet end to end variation. However, throughput is not affected by long distances. In addition to that, the impact percentage varies for each kilometer from one application to another, as well for the same application. This study helps cloud providers to offer their services based on targeted consumers geographical locations in order to ensure high quality of service.
Keywords: Cloud computing; video streaming; real time applications; quality of service; packet end to end delay; response time.
Image Recognitions of Collaborative Drones Security Controls for FPV Systems
by Noriki Uchida, Tomoki Okutake, Noriyasu Yamamoto
Abstract: With the recent growth of the Drones market, the FPV (First Person View) by drones are spreading in various usages such as the promotions or TV programs. However, it is considered that the drones accidents are getting serious problems because of the failures of the operations or malfunctions. Therefore, this paper proposes the collaborative security control systems by multiple drones for the FPV systems, and the image recognition methods of the prototype system are presented. Then, the prototype system used in the open campus events, and the reports of the field usages are discussed for the future studies.
Keywords: Collaborative Security Controls for Drones; Image Recognitions; Wireless Network Systems.
Impact of Node Density and TTL in Vehicular Delay Tolerant Networks: Performance Comparison of Different Routing Protocols
by Kevin Bylykbashi, Evjola Spaho, Leonard Barolli, Fatos Xhafa
Abstract: In this work, we evaluate the performance of different routing protocols in Vehicular
Delay Tolerant Networks (VDTNs). We study the impact of vehicles density and TTL on
the network performance. The simulations are conducted with the Opportunistic Network
Environment (ONE) simulator. The performance is analyzed using delivery probability,
overhead ratio, average latency and average number of hops metrics. The simulation
results show that the increase of node density improves the network performance. In dense
network scenario, the performance of Epidemic and MaxProp routing protocols is better
because the number of opportunistic contacts between nodes increases. For Spray and
Wait the performance is not improved since it uses a maximum of two hops to deliver
bundles. Hence, in dense networks, a bundle may have a significant delay because it can
only be delivered when a relay or source node have and opportunistic contact with the
destination. The increase of ttl from 30 to 120 min does not improve the performance of
three routing protocols in both scenarios. Multiple-copy protocols perform better in terms
of delivery probability compared with single-copy protocol. The single-copy protocol uses
the highest average number of hops and higher average latency compared with multiple-
Keywords: DTN; VDTN; Routing; ONE simulator.
A Design-aware Test Code Approach for Code Writing Problem in Java Programming Learning Assistant System
by Khin Khin Zaw, Nobuo Funabiki
Abstract: To advance Java programming educations, we have developed the Web-based Java Programming Learning Assistant System (JPLAS) that provides the code writing problem among the four type problems with different levels. This problem asks a student to write a Java source code for a given assignment, where the correctness is verified by running the test code on JUnit. Unfortunately, it is found that even after solving many simple problems, a lot of students cannot solve harder problems that require multiple classes/methods, where the proper code design is necessary. In this paper, we propose a design-aware test code approach for the code writing problem in JPLAS. The design-aware test code is generated to test any important method in the model code that has the advisable design for the problem. By writing a code that can pass this test code, a student is expected to implement the code with the proper classes/methods in the model code. For evaluations, we asked seven students to write the source code for the breadth-first-search (BFS) algorithm of a graph without/with using the design-aware test code. Then, only one student could complete it without it, whereas all of them could do so with it. Besides, the code quality metrics measured by Metrics plugin for Eclipse showed that the design-aware test code is very helpful for students to write highly qualitative codes. These results were also confirmed in other graph algorithms.
Keywords: JPLAS; Design-aware test code; JUnit; Metric Plugin; BFS.
A Practical Colour Scheme Explorer for Designers
by Satoru Miura, Hiroaki Nishino
Abstract: Colour scheme design is an important process when designing artwork such as illustrations and graphics. Appropriate colouring maximizes the functional and emotional effects of the work. However, there is no unique solution for properly designing the layout of multiple colours. A designer must have enough skills and experiences for accurately presenting his/her targeting impressive quality of the work. This paper proposes a method for automatically creating and presenting a set of candidate colour layouts by adjusting a few carefully selected colour parameters with harmony. It enables designers to readily explore various colour scheme candidates while considering colour harmony of the work. We implement a colour design support system based on the proposed method and conduct thorough experiments for verifying the effectiveness of the system. We show the proposed method is useful and practical both for experienced and novice users.
Keywords: colour scheme design; colour system; practical colour co-ordinate system; digital artwork.
A Fuzzy Approach for Clustering in MANETs: Performance Evaluation for Different Parameters
by Kosuke Ozera, Shinji Sakamoto, Donald Elmazi, Kevin Bylykbashi, Makoto Ikeda, Leonard Barolli
Abstract: A Mobile Ad hoc Network (MANET) is a multi-hop wireless network in which the mobile nodes are dynamic in nature and has a limited bandwidth and minimum battery power. Due to this challenging environment, the mobile nodes can be grouped into clusters to achieve better stability and scalability. Grouping the mobile nodes is called clustering, in which a leader node is elected to manage the entire network. In this paper, first we introduce various approaches for clustering focused on different performance metrics. Then, we show some clustering schemes. Finally, we present and compare two Fuzzy based systems (called F2SMC1 and F2SMC2) for clustering nodes in MANETs. We consider different parameters for clustering such as: number of nodes in a cluster, node spent power, node security and distance of the node from cluster center. We compare the performance of F2SMC1 and F2SMC2 and show that the F2SMC2 is more complex than F2SMC1, but the F2SMC2 can manage the nodes in the cluster better than F2SMC1. The evaluation results show that by selecting nodes with small distance and high security values, the nodes are closer to cluster center and more secure, so they will remain in the cluster.
Keywords: Fuzzy Logic; MANET; Clustering.
A Search Based Next Hop Selection for Routing in Opportunistic Networks
by Pragya Kuchhal, Sanjay K. Dhurandher, Satya J. Borah, Isaac Woungang, Satbir Jain, Sahil Gupta
Abstract: Opportunistic Network (Oppnet) is one of the challenging fields of wireless network. It is an intermittently connected mobile network where nodes are mobile and no end-to-end path exists. Connectivity among nodes is established when they are within the transmission range of each other. If a node has message to communicate and no intermediate node is available, then the message is stored in the nodes buffer till an appropriate communication opportunity arises which is known as store-carry-forward paradigm. This paradigm has given Oppnets a new direction in the field of research. In any network efficient and effective routing is very crucial. In this paper a novel routing technique has been proposed for Oppnets named as A∗ based opportunistic routing (A∗OR) which uses the A∗ searching technique to select the best forwarders towards the destination. The proposed protocol is compared with Prophet, PROWait and EDR as a benchmark protocols and is found to perform 19%, 11% and 32% better than Prophet, Prowait and EDR respectively in terms of delivery probability.
Keywords: Opportunistic Networks; Delay Tolerant Networks; Opportunistic Network Environment simulator; A∗ search; Epidemic; Prophet; HBPR; EDR; PROWait.