254 research outputs found

    Performance evaluation of two-fuzzy based cluster head selection systems for wireless sensor networks

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    Sensor networks supported by recent technological advances in low power wireless communications along with silicon integration of various functionalities are emerging as a critically important computer class that enable novel and low cost applications. There are many fundamental problems that sensor networks research will have to address in order to ensure a reasonable degree of cost and system quality. Cluster formation and cluster head selection are important problems in sensor network applications and can drastically affect the network’s communication energy dissipation. However, selecting of the cluster head is not easy in different environments which may have different characteristics. In this paper, in order to deal with this problem, we propose two fuzzy-based systems for cluster head selection in sensor networks. We call these systems: FCHS System1 and FCHS System2. We evaluate the proposed systems by simulations and have shown that FCHS System2 make a good selection of the cluster head compared with FCHS System1 and another previous system.Peer ReviewedPostprint (published version

    マルコフ ケッテイ カテイ ソノ カイセツテキ テンボウ

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    A fuzzy-based call admission control system for wireless cellular networks

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    The mobile cellular systems are expected to support multiple services with guaranteed quality of service (QoS). However, the ability of wireless systems to accommodate expected growth of traffic load and broadband services is limited by available radio frequency spectrum. Call admission control (CAC) is one of the resource management functions, which regulates network access to ensure QoS provisioning. However, the decision for CAC is very challenging issue due to user mobility, limited radio spectrum, and multimedia traffic characteristics. To deal with these problems, in this paper, we propose a fuzzy CAC system. We compare the performance of the proposed system with shadow cluster concept (SCC). We evaluate by simulation the performance of the proposed system. The proposed system has a good behavior on deciding the number of accepted connections while keeping the QoS for serving connections.Peer ReviewedPostprint (published version

    A fuzzy-based handover system for avoiding ping-pong effect in wireless cellular networks

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    Many handover algorithms are proposed in the literature. However, to make a better handover and keep the QoS in wireless networks is very difficult. In this paper, we propose a new handover system based on fuzzy logic. The proposed system uses 3 parameters for handoff decision: the change of signal strength of the present Base Station (BS), signal strength from the neighbor BS, and the distance between Mobile Station (MS) and BS. The performance evaluation via simulations shows that proposed system can avoid ping-pong effect and has a good handover decisionPeer ReviewedPostprint (published version

    A glomerular permeability factor produced by human T cell hybridomas

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    A glomerular permeability factor produced by human T cell hybridomas. T cell hybridomas derived from the T cells of a patient with minimal change nephrotic syndrome (MCNS) made a glomerular permeability factor (GPF). Sufficient quantities of GPF were available for further analysis and characterization. We obtained four stable clones of human T cell hybridomas which produced a glomerular permeability factor. When this factor was injected intravenously into rats, significant proteinurias were induced, and in normal human lymphocyte culture, GPF enhanced Concanavalin-A (Con-A) induced lymphocyte histogenesis by greater than ten fold. GPF was cytotoxic to tumor cell lines of epithelial origin, but only cytostatic to tumor cells of hematopoietic origin. Electron microscopy studies, with polyethyleneimine (PEI) staining, indicated that GPF induced the changes in the arrangement of PEI particles and partial fusion of glomerular epithelial cells in the rats given this factor intravenously. The molecular weight of GPF were estimated to be between 60,000 and 160,000 daltons. The molecular weight of the factor and its TNF like activity, we speculated that the factor was a lymphokine, like lymphotoxins

    A comparison study of two fuzzy-based handover systems for avoiding ping-pong effect in Wireless Cellular Networks

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    Wireless mobile networks and devices are becoming increasingly popular to provide users the access anytime and anywhere. The mobile systems are based on cellular approach and the area is covered by cells that overlap each other. Many handover algorithms are proposed in the literature. However, to make a better handover and keep the QoS in wireless networks is very difficult task. For this reason, new intelligent algorithms should be implemented to deal with this problem. In this paper, we carried out a comparison study of two handover systems based on fuzzy logic. We implement two fuzzy-based handover systems (FBHS). We call them FBHS1 and FBHS2. The performance evaluation via simulations shows that FBHS2 has better behavior than FBHS2 and can avoid ping-pong effect in all simulation cases.Peer ReviewedPostprint (published version

    An intelligent fuzzy-based cluster head selection system for WSNs and its performance evaluation for D3N parameter

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    Cluster formation and cluster head selection are important problems in sensor network applications and can drastically affect the network's communication energy dissipation. However, selecting of the cluster head is not easy in different environments which may have different characteristics. In our previous work, in order to deal with this problem, we proposed a power reduction algorithm for sensor networks based on fuzzy logic and number of neighbour nodes. We call this algorithm F3N. In this paper, we evaluate F3N and LEACH by some simulation results. From the simulation results, we found that the probability of a not to be a cluster head is increased with increase of number of neighbour nodes and remained battery power decrease of distance from the cluster centroid.Peer ReviewedPostprint (published version

    Improvement and performance evaluation of CAVENET: a network simulation tool for vehicular networks

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    Vehicle Ad-hoc Network (VANET) is a kind of Mobile Ad-hoc Network (MANET) that establishes wireless connection between cars. In VANETs and MANETs, the topology of the network changes very often, therefore implementation of efficient routing protocols is very important problem. In MANETs, the Random Waypoint (RW) model is used as a simulation model for generating node mobility pattern. On the other hand, in VANETs, the mobility patterns of nodes is restricted along the roads, and is affected by the movement of neighbour nodes. In this paper, we present a simulation system for VANET called CAVENET (Cellular Automaton based Vehicular NETwork). In CAVENET, the mobility patterns of nodes are generated by an 1-dimensional cellular automata. We improved CAVENET and implemented some routing protocols. We investigated the performance of the implemented routing protocols by CAVENET. The simulation results have shown that DYMO protocol has better performance than AODV and OLSR protocols.Peer ReviewedPostprint (published version

    A distributed QoS Routing and CAC framework: performance evaluation of its SSRA and InterD Agents

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    In order to support multimedia communication, it is necessary to develop routing algorithms which use for routing more than one QoS parameters. This is because new services such as video on demand and remote meeting systems require better QoS. Also, for admission control of multimedia applications different QoS parameters should be considered. In our previous work, we proposed an intelligent routing and CAC strategy using cooperative agents. In this paper, we propose and evaluate the performance of SSRA algorithm and a GA-based InterD agent. Performace evaluation shows that proposed agents have a good behaviorPeer ReviewedPostprint (published version

    An intelligent fuzzy-based cluster head selection system for wireless sensor networks and its performance evaluation

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    Sensor networks supported by recent technological advances in low power wireless communications along with silicon integration of various functionalities are emerging as a critically important computer class that enable novel and low cost applications. There are many fundamental problems that sensor networks research will have to address in order to ensure a reasonable degree of cost and system quality. Cluster formation and cluster head selection are important problems in sensor network applications and can drastically affect the network's communication energy dissipation. However, selecting of the cluster head is not easy in different environments which may have different characteristics. In our previous work, in order to deal with this problem, we proposed a power reduction algorithm for sensor networks based on fuzzy logic and number of neighbor nodes. We call this algorithm F3N. In this paper, we implement a simulation system for clustering algorithms in sensor networks. We evaluate LEACH and F3N by some simulation results. Presently, we have implemented LEACH algorithm in NS-2. However, F3N is implemented in MATLAB. We are working to implement also F3N system in NS-2 in order to compare their performance.Peer ReviewedPostprint (published version
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