• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.665-683
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• 2011

Wireless sensor networks (WSN) consist of a large amount of sensor nodes distributed in a certain region. Due to the limited battery power of a sensor node, lots of energy-efficient schemes have been studied. Clustering is primarily used for energy efficiency purpose. However, clustering in WSNs faces several unattained issues, such as ensuring connectivity and scheduling inter-cluster transmissions. In this paper, we propose a location-based spiral clustering (LBSC) algorithm for improving connectivity and avoiding inter-cluster collisions. It also provides reliable location aware routing paths from all cluster heads to a sink node during cluster formation. Proposed algorithm can simultaneously make clusters in four spiral directions from the center of sensor field by using the location information and residual energy level of neighbor sensor nodes. Three logical addresses are used for categorizing the clusters into four global groups and scheduling the intra- and inter-cluster transmission time for each cluster. We evaluated the performance with simulations and compared it with other algorithms.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.998-1007
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• 2018

The advent of Wireless Sensor Networks (WSN) has led to their use in numerous applications. Sensors are autonomous in nature and are constrained by limited resources. Designing an autonomous topology with criteria for economic and energy conservation is considered a major goal in WSN. The proposed honey-hive clustering consumes minimum energy and resources with minimal transmission delay compared to the existing approaches. The honey-hive approach consists of two phases. The first phase is an Intra-Cluster Min-Max Discrepancy (ICMMD) analysis, which is based on the local honey-hive data gathering technique and the second phase is Inter-Cluster Frequency Matching (ICFM), which is based on the global optimal data aggregation. The proposed data aggregation mechanism increases the optimal connectivity range of the sensor node to a considerable degree for inter-cluster and intra-cluster coverage with an improved optimal energy conservation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.964-972
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• 2009

Wireless mesh network (WMN) is emerging a future core technology to resolve many problems derived from exist wireless networks by employing multi-interface and multi-channel. Ability to utilize multiple channels in WMNs substantially increases the effective bandwidth available to wireless network nodes. However, minimum interference channel assignment algorithms are required to use the effective bandwidth in multi-channel environments. This paper proposes a cluster-based minimum interference channel assignment (MI-CA) algorithm to improve the performance of WMN. The MI-CA algorithm is consists of Inter-Cluster and Intra-Cluster Intrchannel assignment between clusters and in the internal clusters, respectively. The Inter-Cluster channel assignment assigns a barebone channel to cluster heads and border nodes based on minimum spanning tree (MST) and the Intra-Cluster channel assignment minimizes channel interference by reassigning ortasgonal channels between cluster mespann. Our simheation results show that MI-CA can improve the performance of WMNs by minimizing channel interference.

• Journal of Information Processing Systems
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• v.10 no.1
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• pp.36-54
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• 2014

Resource sharing is a major advantage of distributed computing. However, a distributed computing system may have some physical or virtual resource that may be accessible by a single process at a time. The mutual exclusion issue is to ensure that no more than one process at a time is allowed to access some shared resource. The article proposes a token-based mutual exclusion algorithm for the clustered mobile ad hoc networks (MANETs). The mechanism that is adapted to handle token passing at the inter-cluster level is different from that at the intra-cluster level. It makes our algorithm message efficient and thus suitable for MANETs. In the interest of efficiency, we implemented a centralized token passing scheme at the intra-cluster level. The centralized schemes are inherently failure prone. Thus, we have presented an intra-cluster token passing scheme that is able to tolerate a failure. In order to enhance reliability, we applied a distributed token circulation scheme at the inter-cluster level. More importantly, the message complexity of the proposed algorithm is independent of N, which is the total number of nodes in the system. Also, under a heavy load, it turns out to be inversely proportional to n, which is the (average) number of nodes per each cluster. We substantiated our claim with the correctness proof, complexity analysis, and simulation results. In the end, we present a simple approach to make our protocol fault tolerant.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.279-284
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• 2013

This paper proposes a new cluster-based routing protocol for assuring the service lifetime of wireless multimedia sensor networks. The proposed protocol performs the intra-cluster routing and inter-cluster routing to reduce the energy consumption and service lifetime in the wireless sensor multimedia computing environment, and the proposed mechanism enhances the routing reliability, and it minimizes the packet loss, overhead, and energy consumption. The simulation results show that the proposed mechanism outperforms DSR and AODV.

• Journal of Navigation and Port Research
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• v.31 no.7
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• pp.623-628
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• 2007

By employing primarily the Kendall's Concordance Test, the paper attempted to conduct an experts' evaluation on the interaction among the agents in Busan marine tourism cluster and recommend some measures for policy consideration for the cluster's activation. For this purpose, a conceptual framework was developed to guide the assessment by using inter-agent cooperation and network approaches regarding the nature of the marine tourism cluster. Such factors as cooperation, competition, relationship marketing, and networking were identified as critical. Findings of the study imply that Busan marine tourism cluster is at its embryonic stage and needs desperate measures for improvement in the inter-organizational cooperation and networking, the major regional characteristics that determine the competitiveness of marine tourism.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.10
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• pp.33-51
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• 1997

On ATM-based wired/wireless integrated network, we apply the connection re-routing method[1] which reduced the inter-cluster handoff delay by reserving VPI/VCLs for possible inter-cluster handoff calls in advance. Additionally, we propose wired resource reservation methods, which are ausiliary method and split method, for handoff QoS guarantee of various expected services. The characteristics of these methods reserve wired connection resources based on the information on the possible inter-cluster handoff calls. With mathematical analysis, we also propose each algorithm and cost function for deciding an optimal amount in reserving resources. With numberical examples, we can see that the auxiliary method effectively reduces the cost in all cases(.alpha.>.betha., .alpha.=.betha., and .alpha.<.betha.). The split method has a little cost-reduction effects, when handoffs call does not have priority over new calls (that is, .alpha..leq..betha.) and the total capacity is relatively large. In other cases, the split method, however, has effective cost-reduction effects. The numerical resutls show that these reservation methods ca flexibly cope with the time-variant environment and meet the QoS requriements on the inter-cluster handoff calls.

• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.86-91
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• 2007

A representative group of 38 improved basmati lines including maintainers of sterile lines were studied for genetic diversity utilizing Mahalanobis $D^2$ statistics. A wide diversity was observed having ten clusters with high intra- and inter-cluster distance. Heterosis was estimated utilizing the cytoplasmic male sterile lines from the clusters having high intra- and inter-cluster distance. Highly heterotic hybrids were obtained from the hybridization programme. Cross combinations IR68281A/Pusa 1235-95-73-1-1, IR68281A/RP 3644-41-9-5, Pusa 3A/UPR 2268-4-1, IR 68281A/Pusa Basmati-1, IR68281A/BTCE 10-98, and IR58025A/HKR 97-401 were found to be highly heterotic for grain yield/plant with other agronomic and quality traits. Additionally, a positive association of intra-cluster distance with heterosis was observed, which could be utilized as a guideline for predicting heterosis in basmati hybrid rice breeding program. Also, a positive association between inter-cluster distance and heterosis was observed.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.39-51
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• 1998

In this paper, we propose signaling procedures amon network elements for a connection rerouting method which can reduce inter-switch handoff processing delay reduces the delay in the connection re-routing by reserving VPI/VCIs for possible inter-switch handoff calls in advance. Additionally, we mathematically analyze the signaling procedures and then suggest solutions to the relations with cluser size, network topoloty, handoff-request rete and handoff delay. With simulation, the solutions are validated. From numerical examples, we concluded taht handoff delay, one of the handoff QoSs, can be satisfied by adjusting the cluster size and network topology according to the handoff -request rate of service area. With our proposed signaling and analytic methods, we concluded that the connection rerouting method using cluster-sectoring effectively reduces the delay of inter-switch handoff processing than dynamic connection rerouting method. Our solutions are useful in guaranteeing the requested handoff delay (especially, inter-switch handoff delay) when the connection rerouting method is applied to ATM-based wireless/wired integrated network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.389-392
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• 2007

In this paper, we propose an algorithm that improve network lifetime by adjusting cluster size according to location information of sensor node in wireless sensor network (WSN) using clustering technique. The sensed information in each cluster transfers to sink node through inter-cluster communications. Cluster head (CH) that nearby located in sink node much more spend own energy than far away CHs, because nearer CH forwards more data, so network lifetime is decreased. Proposed algorithm minimizes energy consumption in adjacent cluster to sink node by decreasing cluster site, and improve CH lifetime by distributing transmission paths. As a result of analysis, the proposed algorithm shows longer network lifetime in WSN.