• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.57-62
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• 2006

건축디자인 초기단계에서 다이어그램은 아이디어 및 디자인 해결방안을 도출하기 위한 분석 도구로써 중요한 의미를 지닌다(Wang, 1999; Do, 1997). 이러한 다이어그램은 시각적 디자인 피드백을 가능하게 함으로써 건축디자인 실무 및 교육에서 필수적인 디자인 도구라고 할 수 있다 (Schon and Wiggins, 1992; Gross, 1996; Kurmann, 1998). 최근에 IT 기술이 건축분야에 적용됨에 따라, 건축가들의 전통적으로 고려되어 왔던 인간의 행동, 자연현상, 건축재료, 건축부재, 대지조건 외에 다양한 IT 기술과 관련된 정보를 분석하고 고려할 필요성을 가지게 되었다. 그러나 이러한 다양한 IT 기술은 건축적인 요소들과 접목되어 적용되기 때문에 건축가들은 디자인 초기단계부터 IT 기술의 접목이 가능한 디자인 도구를 필요로 하게 되었다. 즉, 이는 IT 정보와 공간정보와의 관계 및 적용을 건축가가 빠르게 이해하고 분석하고 이를 디자인에 반영할 수 있도록 도와주는 시각적 다이어그램 표출이 가능한 디자인 도구가 필요하게 되었다. 본 논문에서는 다양한 IT 기술과 공간 정보의 다양한 형태의 관계를 나타내는 3 차원 버블 다이어그램을 이용한 계략 디자인 방법을 제안하고, 이를 기반으로 3 차원 버블 다이어그램을 지원하면서 건축 디자인 초기단계에 이용 가능한 디자인 도구를 개발한다. 본 연구에서 개발된 디자인 도구는 정보의 유형에 따라 다양하게 형태를 변화시킬 수 있는 노드(node)와 연결선(edge)로 구성되고, 저장된 특정 건축정보는 다이어그램으로 생성된 디자인 대안을 평가하는데 사용된다. 일종의 DSS(Decision Support System)인 본 시스템은 디자인 초기단계에서 3 차원 디자인 아이디어를 제공할 뿐만 아니라 다양한 디자인 대안을 빠르게 생성하고 이를 실시간으로 평가함으로써 디자인 효율성을 증가시킬 것이다. 본 시스템은 유비쿼터스 기술이 적용된 신도시에 생성될 통관관제센터 디자인에 실험적으로 적용되었다.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.923-930
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• 2004

Wireless sensor networks is a core technology of ubiquitous computing which enables the network to aware the different kind of context by integrating exiting wired/wireless infranet with various sensor devices and connecting collected environmental data with applications. However it needs an energy-efficient approach in network layer to maintain the dynamic ad hoc network and to maximize the network lifetime by using energy constrained node. Cluster-based data aggregation and routing are energy-efficient solution judging from architecture of sensor networks and characteristics of data. In this paper. we propose a new distributed clustering algorithm in using distance from the sink. This algorithm shows that it can balance energy dissipation among nodes while minimizing the overhead. We verify that our clustering is more en-ergy-efficient and thus prolongs the network lifetime in comparing our proposed clustering to existing probabilistic clustering for sensor network via simulation.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.855-864
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• 2005

In this paper, we propose an intrusion detection system(IDS) architecture which can detect and respond against the generation of abnormal traffic such as malicious code and Internet worms. We model the system, design and implement a simulator using OPNET Modeller, for the performance analysis on the response capacity of alert information in the proposed system. At first, we model the arrival process of alert information resulted from abnormal traffic. In order to model the situation in which alert information is intensively produced, we apply the IBP(Interrupted Bernoulli Process) which may represent well the burstiness of traffic. Then we perform the simulation in order to gain some quantitative understanding of the system for our performance parameters. Based on the results of the performance analysis, we analyze factors which may hinder in accelerating the speed of security node, and would like to present some methods to enhance performance.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.9
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• pp.461-476
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• 2003

Due to the implementation ease and alleviation of memory bottleneck effect, NUMA architecture has dominated in the multiprocessor systems for the past several years. However, because the NUMA system distributes memory in each node, frequent remote memory access is a key factor of performance degradation. Therefore, efficient design of RAC(Remote Access Cache) in NUMA system is critical for performance improvement. In this paper, we suggest Multi-Grain RAC which can adaptively control the RAC line size, with respect to each application behavior Then we simulate NUMA system with multi-grain RAC using MINT, event-driven memory hierarchy simulator. and analyze the performance results. At first, with profile-based determination method, we verify the optimal RAC line size for each application and, then, we compare and analyze the performance differences among NUMA systems with normal RAC, with optimal line size RAC, and with multi-grain RAC. The simulation shows that the worst case can be always avoided and results are very close to optimal case with any combination of application and RAC format.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.87-103
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• 2006

Advances in computer and network technology provide new computing environment that were only possible with supercomputers before. In order to provide the environment, a distributed runtime system has to be provided, but most of the conventional distributed runtime systems lack in providing dynamic and flexible system reconfiguration depending on workload variance, due to a static architecture of fixed master node and slave working nodes. This paper proposes and implements a new model for distributed job allocation and management which is a distributed runtime system is P2P environment for flexible and dynamic system reconfiguration. The implemented systems enables job program transfer and management, remote compile and execution among cooperative developers based on P2P standard protocol Jxta platform. Since it makes dynamic and flexible system reconfiguration possible, the proposed method has some advantages in that it can collect and utilize idle computing resources immediately at a needed time for distributed job processing. Moreover, the implemented system's effectiveness and performance increase are shown by applying and processing the crawler jobs, in a distributed way, for collecting a large amount of data needed for internet search.

• Journal of Internet Computing and Services
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• v.9 no.2
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• pp.35-42
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• 2008

Mobile IP is a solution to support mobile nodes, however, it does not handle NEtwork MObility (NEMO). The NEMO Basic Support (NBS) protocol ensures session continuity for all the nodes in the mobile network. Since the protocol is based on Mobile IP, it inherits the same fundamental problem such as tunnel convergence, when supporting the multicast for NEMO. In this paper, we propose the multicast route optimization scheme for NEMO environment. We assume that the Mobile Router (MR) has a multicast function and the Nested Mobile Router Information (NeMRI) table. The NeMRI is used to record o list of the CoAs of all the MRs located below it. And it covers whether MRs desire multicast services. Any Route Optimization (RO) scheme can be employed here for pinball routing. Therefore, we achieve optimal routes for multicasting based on the given architecture. We also propose cost analytic models to evaluate the performance of our scheme. We observe significantly better multicast cost in NEMO compared with other techniques such as Bi-directional Tunneling, Remote Subscription, and Mobile Multicast based on the NBS protocol.

• Journal of Internet Computing and Services
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• v.8 no.6
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• pp.21-28
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• 2007

Hierarchical Mobile IPv6 improves performance of Mobile IPv6 by managing Binding Update in terms of location, With improved handover delay, realization of delay-sensitive services (e,g, VoIP or video streaming) has become more persuadable, Comparing with Mobile IPv6, however, Hierarchical Mobile IPv6 brings security threats related to Local Binding Update to mobile network, In the RFC 4140, specific methods to authenticate Local Binding Update message are not explicitly presented. It is essential that design secure architecture to address problems related to authenticating Local Binding Update, Many secure suggestions for Local Binding Update, however, concentrate on infrastructure-based solutions such as AAA PKI. These approaches may cause scalability problem when the suggested solutions are applied to real network. Therefore we suggest authentication method that doesn't require infrastructure, In addition to authentication of Local Binding Update, our method also provides mobile node with power saving ability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.414-422
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• 2011

This paper describes a design of low-density parity-check(LDPC) decoder supporting block length 2,304-bit and code rate 1/2 of IEEE 802.16e mobile WiMAX standard. The designed LDPC decoder employs the min-sum algorithm and partially parallel layered-decoding architecture which processes a sub-matrix of $96{\times}96$ in parallel. By exploiting the properties of the min-sum algorithm, a new memory reduction technique is proposed, which reduces check node memory by 46% compared to conventional method. Functional verification results show that it has average bit-error-rate(BER) of $4.34{\times}10^{-5}$ for AWGN channel with Fb/No=2.1dB. Our LDPC decoder synthesized with a $0.18{\mu}m$ CMOS cell library has 174,181 gates and 52,992 bits memory, and the estimated throughput is about 417 Mbps at 100-MHz@l.8-V.

• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.155-162
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• 2010

To ensure accurate measurements of wireless network performance, it should be collected real-time data which are transmitted between a large number of nodes in the actual network environment. Therefore, it is necessary to develop simulation tool for finding optimal network system design method such as media access control, routing technique, ad-hoc algorithm of node deployment while overcoming spatial and temporal constraints. Our research attempts to provide an improved architecture and design method of simulation tool for wireless network is an application of multi-threading technique in these issues. We finally show that usability of the proposed simulator by comparing results derived from same test environment in the wireless LAN model of our simulator and widely used network simulation package, NS-2.

• The Journal of Society for e-Business Studies
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• v.4 no.1
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• pp.87-101
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• 1999

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the control devices located in common manufacturing zone and operated by connecting them. In this paper, functional standard of the network layers are set as physical and data link layer of IEEE 802.2, 802.4, and VMD application layer and ISO-CIM reference model. Then, they are divided as minimized architecture, designed as group objects which perform group management and service objects which organizes and operates the group. For the stability in this network, this paper measures the variation of data packet length and node number and analyzes the variated value of the waiting time for the network operation. For the method of the analysis, non-exhausted service method are selected, and the arrival rates of the each data packet to the nodes that are assumed to form a Poission distribution. Then, queue model is set as M/G/1, and the analysis equation for waiting time is found. For the evalution of the performance, the length of the data packet varies from 10 bytes to 100 bytes in the operation of the group management network, the variation of the wating time is less than 10 msec. Since the waiting time in this case is less than 10 msec, response time is fast enough. Furthermore, to evaluate the real time processing of the group management network, it shows if the number of nodes is less than 40, and the average arrival time is less than 40 packet/sec, it can perform stable operation even taking the overhead such as software delay time, indicated packet service, and transmissin safety margin.