• Journal of the Korea Society of Computer and Information
• /
• v.20 no.4
• /
• pp.77-85
• /
• 2015

Recently, wireless sensor network(WSN) have been used in various fields to implement ubiquitous computing environment. WSN uses small, low cost and low power sensors in order to collect information from the sensor field. This paper proposes a clustering algorithm for energy efficiency of sensor nodes. The proposed algorithm is based on conventional LEACH, the representative clustering protocol for WSN and it prolongs network and nodes life time using sleep technique and changable transmission mode. The nodes of the proposed algorithm first calculate their clustering participation value based on the distance to the neighbor nodes. The nodes located in high density area will have clustering participation value and it can turn to sleep mode. Besides, proposed algorithm can change transmission method from conventional single-hop transmission to multi-hop transmission according to the energy level of cluster head. Simulation results show that the proposed clustering algorithm outperforms conventional LEACH, especially non-uniformly deployed network.

• Journal of Digital Convergence
• /
• v.14 no.1
• /
• pp.171-179
• /
• 2016

The energy consumption problem in wireless sensor networks is investigated. The problem is to expend as little energy as possible receiving and transmitting data, because of constrained battery. In this paper, in order to extend the lifetime of the network, we proposed a location-based clustering algorithm for wireless sensor network with skewed-topology. The proposed algorithm is to deploy multiple child nodes at the sink to avoid bottleneck near the sink and to save energy. Proposed algorithm can reduce control traffic overhead by creating a dynamic cluster. We have evaluated the performance of our clustering algorithm through an analysis and a simulation. We compare our algorithm's performance to the best known centralized algorithm, and demonstrate that it achieves a good performance in terms of the life time.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.47 no.3
• /
• pp.83-89
• /
• 2010

Scalable routing is one of the key challenges in designing and operating large scale MANETs. Performance of routing protocols proposed so far is only guaranteed under various limitation, i.e., dependent of the number of nodes in the network or needs the location information of destination node. Due to the dependency to the number of nodes in the network, as the number of nodes increases the performance of previous routing protocols degrade dramatically. We propose Cluster Overlay Dynamic Source Routing (CODSR) protocol. We conduct performance analysis by means of computer simulation under various conditions - diameter scaling and density scaling. Developed algorithm outperforms the DSR algorithm, e.g., more than 90% improvement as for the normalized routing load. Operation of CODSR is very simple and we show that the message and time complexity of CODSR is independent of the number of nodes in the network which makes CODSR highly scalable.

• Journal of KIISE
• /
• v.45 no.3
• /
• pp.224-233
• /
• 2018

Recently, there are many of studies on SWRL reasoning engine based on user-defined rules in a distributed environment using a large-scale ontology. Unlike the schema based axiom rules, efficient inference orders cannot be defined in SWRL rules. There is also a large volumet of network shuffled data produced by unnecessary iterative processes. To solve these problems, in this study, we propose a method that uses Map-Reduce algorithm and distributed in-memory framework to deduce multiple rules simultaneously and minimizes the volume data shuffling occurring between distributed machines in the cluster. For the experiment, we use WiseKB ontology composed of 200 million triples and 36 user-defined rules. We found that the proposed reasoner makes inferences in 16 minutes and is 2.7 times faster than previous reasoning systems that used LUBM benchmark dataset.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.188-194
• /
• 2007

We propose a new ad hoc multicast routing protocol for based on the ontology scheme called inference network. Ontology knowledge-based is one of the structure of context-aware. We will have developed an algorithm that will design multi-hierarchy Layered networks to simulate a desired system.

• Journal of KIISE:Software and Applications
• /
• v.32 no.10
• /
• pp.963-973
• /
• 2005

Increasing attention is being recently devoted to various problems inherent in the topological design of networks systems. The topological structure of these networks can be based on service centers, terminals (users), and connection cable. Lately, these network systems are well designed with tiber optic cable, because the requirements from users become increased. But considering the high cost of the fiber optic cable, it is more desirable that the network architecture is composed of a spanning tree. In this paper, we present a GA (Genetic Algorithm) for solving bicriteria network topology design problems of wide-band communication networks connected with fiber optic cable, considering the connection cost, average message delay, and the network reliability We also employ the $Pr\ddot{u}fer$ number (PN) and cluster string in order to represent chromosomes. Finally, we get some experiments in order to certify that the proposed GA is the more effective and efficient method in terms of the computation time as well as the Pareto optimality.

• Management & Information Systems Review
• /
• v.29 no.4
• /
• pp.169-186
• /
• 2010

This study aims to reveal the ways to sharpen the edges of Korean companies through the relativity analysis between knowledge management and innovational cluster in environmental changes in resent Busan. That is, according to the knowledge management approach, the methods and directions of strengthening industrial competition were established, while the strategy of innovational clusters was suggested as a way of expanding and encouraging knowledge management. The key words of innovational cluster are in this research are the framework of Cluster theory, the importance of innovational cluster, and the change of managerial strategy paradigm. This study provide the several implication for the practice of knowledge management and the researchers. Based on these theories of knowledge management and industrial clusters, their close relationships were analyzed. As a result, industrial clusters were found to be effectively utilized to enlarge and deepen knowledge management. In addition, this suggests the efficient operation guideline of knowledge management. this study indicates both knowledge and innovational cluster should be operated and handled together in the managerial strategy. but this research has limitations in generaling the study result because it collects data from local firms only in Busan.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2003.05b
• /
• pp.959-962
• /
• 2003

멀티미디어 서비스 수요의 증가는 네트워크 상에서 기존의 문자기반의 컨텐츠 제공 서비스의 수요를 이미 앞질렀으며 네트워크와 시스템 자원의 발전에 따라 사용자 요구는 그에 따라 더욱 폭 넓게 증가하고 있다. 우수한 품질의 동영상 데이터를 온라인 상에서 품질 저하 없이 서비스 받을 수 있는 것을 넘어 사용자는 컨텐츠에 파생되는 부가의 서비스를 요구하게 되었고 이는 기존의 텍스트 정보에 의한 양방향 서비스가 아닌 사용자의 요구에 따른 멀티미디어 컨텐츠 자체에 대한 서비스를 위한 정보시스템이 필요하게 되었음을 의미한다. 본 논문에서는 객체 단위의 동영상을 실시간으로 합성하여 이를 사용자에게 즉시 서비스하는 양방향 멀티미디어 서버 시스템의 설계와 구현에 대해 기술하였다. 구현된 시스템은 사용자에게 일방적인 데이터를 전송하는 기존의 시스템과 달리 적용 가능한 객체 단위 동영상을 합성 전송하고 자동 추출된 실시간 오브젝트를 다양한 배경화면과 함께 합성하여 서비스 할 수 있는 기능 구조를 가진다. 또한 멀티미디어 서버의 주요 목표를 반영하여 확장과 성능을 고려한 클러스터 On-Demand 서버를 구성하였으며 서버와 서비스 관리를 위한 모든 구성요소를 포함하여 실제 서비스가 가능한 완전한 미디어 시스템을 설계 구현하였다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.8B
• /
• pp.1003-1011
• /
• 2011

In this paper, a real-time multi-source sensor data management system based on wireless sensor network is proposed and implemented. The proposed management system is designed to transmit the wireless data to the server in order to monitor and control the multi-source target's status efficiently by analyzing them. The proposed system is implemented to make it possible to control and transmit the wireless sensor data by classifying them, of which data are issued from the clustered sources composed of a number of the remote multiple sensors. In order to evaluate the performance of the proposed system, we measure and analyze both the transmission delay time according to the distance and the data loss rate issued from multiple data sources. From these results, it is verified that the proposed system has a good performance.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.12 no.2
• /
• pp.105-115
• /
• 2017

Innovative cluster theory promotes cluster growth as the tacit knowledge and know-how approach becomes easier through industry-academia cooperation. Industry-academia cooperation is an innovation network policy that supports joint research between industry and academia. In this respect, The Flow of recent government policy is activating I-U support office in university & research institute for enable I-U Cooperation ecosystem. Then SMB Administration was first performed "research village support program", to support SMEs in industry-university cooperative research capabilities by integrating the research, development and commercializatin of the university or research institution with excellent research base in 2013. However, I-U Cooperation R&D must be based the link strategy of Localization in order to be better composition at research village. In the case of research villages where specialized discovery strategies are well reflected, integration of similar companies in specialized fields will naturally create clusters and create synergy of research. This study searching and summarizing through a recent Hanbat National University research village. Finally, we propose the implications of government policy.