• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.762-764
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• 1998

완전 이진트리의 통신형태를 갖는 분활 정복방식의 알고리즘 병렬 컴퓨터에서 실행시킬 때 작업들을 프로세서에 분배하여 처리하게 되는데 이때 통신 링크의 충돌을 줄이는 것이 전체 실행시간을 단축하는 중요한 요소가 된다. 본 논문에서는, 웜홀 라우팅과 양방향 링크를 지원하는 3차원 메쉬로의 완전 이진트리의 임베딩 문제를 다룬다. 이 임베딩 방법은 순위차원 라우팅을 사용하며 링크 충돌이 없는 방법으로 최적의 임베딩 알고리즘이다.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.430-432
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• 1999

인터넷 멀티캐스트 라우팅을 위해 PIM, CBT, DVMR 등의 여러 가지 프로토콜이 연구되고 있다. 본 논문에서는 이와 같은 멀티캐스트 라우팅에서 QoS를 보장하기 위한 새로운 방법을 제시한다. 이 방법은 멀티캐스팅 라우팅의 두가지 접근법 중 공유 트리 접근법에서 지연시간에 대한 QoS를 보장하는 방법으로 PIM-SM을 개선한 형태를 취한다. 동적인 멤버쉽에 의해 주어진 지연시간 상한값을 만족하지 않는 상황이 발생하면 공유 트리의 RP(Rendezvous Point)를 다시 선택하고 트리를 제구성함으로서 QoS를 보장하는 방법을 사용하며, 시뮬레이션을 통해 이 방법의 적절성을 확인하였다.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.131-132
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• 2007

In this paper, we designed and implemented bio-signals transmission and storage system using wireless sensor network based on ZigBee. Wireless sensor network is organized with routing protocol based on tree structure. The data is transmitted to monitoring system based on SIP. ZigBee will be used as various combinations with other wireless network technologies for application purposes.

• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1275-1281
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• 2011

Many authors studied cooperative games that arise from variants of dominating set games on graphs. In wireless networks, the connected dominating set is used to reduce routing table size and communication cost. In this paper, we introduce a connected dominating set game to model the cost allocation problem arising from a connected dominating set on a given graph and study its core. In addition, we give a polynomial time algorithm for determining the balancedness of the game on a tree, for finding a element of the core.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4343-4355
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• 2014

Multicast group communication has many advantages in data centers and thus is widely used by many applications. It can efficiently reduce the network traffic and improve the application throughput. For the multicast application in data centers, an essential problem is how to find a minimal multicast tree, which has been proved to be NP-hard. In this paper, we propose an approximation tree-building method for the minimal multicast problem, named HD（Hamming Distance）-based multicast tree. Consider that many new network structures have been proposed for data centers. We choose three representative ones, including BCube, FBFLY, and HyperX, whose topological structures can be regarded as the generalized hypercube. Given a multicast group in BCube, the HD-based method can jointly schedule the path from each of receiver to the only sender among multiple disjoint paths; hence, it can quickly construct an efficient multicast tree with the low cost. The experimental results demonstrate that our method consumes less time to construct an efficient multicast tree, while considerably reduces the cost of the multicast tree compared to the representative methods. Our approach for BCube can also be adapted to other generalized hypercube network structures for data centers after minimal modifications.

• The KIPS Transactions:PartA
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• v.10A no.4
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• pp.369-374
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• 2003

Ant Algorithm is used to find the solution of Combinatorial Optimization Problems. Real ants are capable of finding the shortest path from a food source to their nest without using visual informations. This behavior of real ants has inspired ant algorithm. There are various versions of Ant Algorithm. Ant Colony System (ACS) is introduced lately. ACS is applied to the Traveling Salesman Problem (TSP) for verifying the availability of ACS and evaluating the performance of ACS. ACS find a good solution for TSP When ACS is applied to different Combinatorial Optimization Problems, ACS uses the same parameters and strategies that were used for TSP. In this paper, ACS is applied to the Multicast Routing Problem. This Problem is to find the paths from a source to all destination nodes. This definition differs from that of TSP and differs from finding paths which are the shortest paths from source node to each destination nodes. We introduce parameters and strategies of ACS for Multicasting Routing Problem.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.571-573
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• 2018

Wireless sensor networks have unbalanced energy consumption due to the convergence structure in which data is concentrated to sink nodes. To solve this problem, in the previous research, the relay node was placed between the source node and the sink node to merge the data before being concentrated to the sink node. However, selecting a relay node that does not consider the link quality causes packet loss according to the link quality of the reconfigured routing path. Therefore, in this paper, we propose a link cost calculation method for data reliability in routing path reconfiguration for relay node selection. We propose a link cost estimation formula considering the number of hops and RSSI as the routing metric value and select the RSSI threshold value through the packet transmission experiment between the sensor modules.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.11
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• pp.64-74
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• 1999

A new clock skew optimization for clock routing using link-edge insertion is proposed in this paper. It satisfies the given skew bound and prevent the total wire length from increasing. As the clock skew is the major constraint for high speed synchronous ICs, it must be minimized in order to obtain high performance. But clock skew minimization can increase total wire length, therefore clock routing is performed within the given skew bound which can not induce the malfunction. Clock routing under the specified skew bound can decrease total wire length Not only total wire length and delay time minimization algorithm using merging point relocation method but also clock skew reduction algorithm using link-edge insertion technique between two nodes whose delay difference is large is proposed. The proposed algorithm construct a new clock routing topology which is generalized graph model while previous methods uses only tree-structured routing topology. A new cost function is designed in order to select two nodes which constitute link-edge. Using this cost function, delay difference or clock skew is reduced by connecting two nodes whose delay difference is large and distance difference is short. Furthermore, routing topology construction and wire sizing algorithm is developed to reduce clock delay. The proposed algorithm is implemented in C programming language. From the experimental results, we can get the delay reduction under the given skew bound.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3B
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• pp.143-152
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• 2007

In order to provide new value-added services such as a policy-based routing and the quality of services in next generation network, the Internet routers need to classify packets into flows for different treatments, and it is called a packet classification. Since the packet classification should be performed in wire-speed for every packet incoming in several hundred giga-bits per second, the packet classification becomes a bottleneck in the Internet routers. Therefore, high speed packet classification algorithms are required. In this paper, we propose an efficient packet classification architecture based on a hierarchical binary search fee. The proposed architecture hierarchically connects the binary search tree which does not have empty nodes, and hence the proposed architecture reduces the memory requirement and improves the search performance.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.429-436
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• 2009

Odd network was introduced as one model of graph theory. In [1], it was introduced as a class of fault-tolerant multiprocessor networks and analyzed so many useful properties such as simple routing algorithms, maximal fault tolerance, node axsjoint path, etc. In this paper, we sauw a construction algorithm of edge-axsjoint spanning trees in Odd network $O_d$. Also, we prove that edge-disjoint spanning tree generated by our algorithm is optimal edge-disjoint spanning tree.