• Journal of KIISE:Computer Systems and Theory
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• v.29 no.1
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• pp.10-15
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• 2002

This paper proposes the Pipelined Broadcast that broadcasts a message of size m in O(m+n-1) time in an n-dimensional hypercube. It is based on the replication tree, which is derived from the reachable sets. It greatly improves the performance compared to Ho-Kao s algorithm with the time of O(m[n/log(n+1)]). The communication in the broadcast uses all-port wormhole router with message replication capability. This paper includes the algorithm together with performance comparisons to previous schemes in practical implementation.

• Journal of Electrical Engineering and information Science
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• v.2 no.3
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• pp.1-6
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• 1997

This paper describes the design of a network interface controller (NIC) chip which is to be used to support a novel adaptive virtual cut-through routing method for parallel compute systems with direct (i.e., point-to-point) interconnection networks. The NIC chip is designed to provide the interface between a processing node constructed from commercially available microprocessors and another custom-designed router chip, which in turn performs the actual routing of packets to their respective destinations. The NIC, designed using a semi-full-custom VLSi design technique outperform traditional wormhole routing with a minimal amount of hardware overhead. The NIC design has been fully simulated and laid out using a 0.8$\mu\textrm{m}$ CMOS process.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.147-156
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• 2001

A high performance routing switch is an essential device to either the high performance parallel processing or communication networks that handle multimedia transfer systems such as VOD. The high performance routing chip called STC104 is a typical example in the technical aspect which has 32 bidirectional links of 100Mbps transfer sped. It has exploited new technologies, such as wormhole routing, interval labeling, and adaptive routing method. The high speed router has been applied into some parallel processing system as a single chip. However, its performance over the various interconnection networks with multiple routing chips has not been studied. In this paper, the strucrtures and characteristics of the STC104 have been investigated in order to evaluate the high speed router. Various topology of the STC104, such as meshes, torus, and N-cube are defined and constructed. Algorithms of packet transmission have been proposed based on the interval labeling and the group adaptive routing method implemented in the interconnected network. Multicast algorithms, which are often requited to the processor networks and broadcasting systems, modified from U-mesh and U-torus algorithms have also been proposed overcoming the problems of point-to-point communication.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4644-4661
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• 2015

Wireless sensor networks are often organized in the form of clusters leading to the new framework of WSN called cluster or hierarchical WSN where each cluster head is responsible for its own cluster and its members. These hierarchical WSN are prone to various routing layer attacks such as Black hole, Gray hole, Sybil, Wormhole, Flooding etc. These routing layer attacks try to spoof, falsify or drop the packets during the packet routing process. They may even flood the network with unwanted data packets. If one cluster head is captured and made malicious, the entire cluster member nodes beneath the cluster get affected. On the other hand if the cluster member nodes are malicious, due to the broadcast wireless communication between all the source nodes it can disrupt the entire cluster functions. Thereby a scheme which can detect both the malicious cluster member and cluster head is the current need. Abnormal energy consumption of nodes is used to identify the malicious activity. To serve this purpose a learning based energy prediction algorithm is proposed. Thus a two level energy prediction based intrusion detection scheme to detect the malicious cluster head and cluster member is proposed and simulations were carried out using NS2-Mannasim framework. Simulation results achieved good detection ratio and less false positive.

• ETRI Journal
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• v.43 no.4
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• pp.674-683
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• 2021

A trust-aware secure routing protocol (TSRP) for wireless sensor networks is proposed in this paper to defend against varieties of attacks. First, each node calculates the comprehensive trust values of its neighbors based on direct trust value, indirect trust value, volatilization factor, and residual energy to defend against black hole, selective forwarding, wormhole, hello flood, and sinkhole attacks. Second, any source node that needs to send data forwards a routing request packet to its neighbors in multi-path mode, and this continues until the sink at the end is reached. Finally, the sink finds the optimal path based on the path's comprehensive trust values, transmission distance, and hop count by analyzing the received packets. Simulation results show that TSRP has lower network latency, smaller packet loss rate, and lower average network energy consumption than ad hoc on-demand distance vector routing and trust based secure routing protocol.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.8
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• pp.25-32
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• 2011

Networks-on-chip (NoC) is emerging as a key technology to overcome severe bus traffics in ever-increasing complexity of the Multiprocessor systems-on-chip (MPSoC); however traditional electrical interconnection based NoC architecture would be faced with technical limits of bandwidth and power consumptions in the near future. In order to cope with these problems, a hybrid optical NoC architecture which use both electrical interconnects and optical interconnects together, has been widely investigated. In the hybrid optical NoCs, wormhole switching and simple deterministic X-Y routing are used for the electrical interconnections which is responsible for the setup of routing path and optical router to transmit optical data through optical interconnects. Optical NoC uses circuit switching method to send payload data by preset paths and routers. However, conventional hybrid optical NoC has a drawback that concurrent transmissions are not allowed. Therefore, performance improvement is limited. In this paper, we propose a new routing algorithm that uses circuit switching and adaptive algorithm for the electrical interconnections to transmit data using multiple paths simultaneously. We also propose an efficient method to prevent livelock problems. Experimental results show up to 60% throughput improvement compared to a hybrid optical NoC and 65% power reduction compared to an electrical NoC.

• 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 Korea Association of Information Systems Conference
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• 1998.10a
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• pp.145-149
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• 1998

본 논문에서는 동일한 목적지 노드들의 집합을 가지는 다중 멀티캐스트(multiple multicast)가 동시에 일어날 경우 노드간의 경쟁을 최소화하고 메시지 전송 경로를 단축시 키기 위한 알고리즘을 제시하고, 2차원 네트워크인 토러스 구조에서 제시된 본 논문의 알고 리즘을 기존 알고리즘과 비교한다. 기존 논문에서는 멀티캐스트 메시지 패싱 시스템 (multicast message-passing system)에서 여러 개의 소스노드로부터 목적지 노드가 중첩 되는 다중 멀티캐스트를 구현하기 위한 방법으로 2차원 메쉬 구조의 특징을 이용한 SCHL(Source-Centered Hierarchical Leader) 기법[7,8]이 제안되었다. 본 논문에서는 이 를 토러스 구조에 적합하게 변형하여, 기존의 메쉬 구조에 적용된 SCHL 기법[7]과 성능을 분석함으로써 제안된 알고리즘이 메쉬 구조보다 토로스 구조에서 구현될 때, 더 향상된 성 능을 가진다는 것을 보인다. 본 논문에서의 메시지 전송기법은 결정적 웜홀 라우팅 방식을 이용한다.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.2836-2838
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• 1999

고신뢰도의 요구를 보장하는 병렬 구조의 분산시스템의 사용이 증가함에 따라 네트워크 상에서 메시지전달을 방해하는 요소고장의 영향을 최소화시킬 수 있는 고장포용 라우팅에 대한 중요성이 부각되고 있다. 그러나, 네트워크의 복잡한 환경 때문에 요소고장을 극복하기 위한 고장포용 라우팅 알고리즘의 설계는 쉬운 일이 아니다. 본 논문에서는 2차원 메쉬 네트워크에 적용되는 최적의 고장포용 라우팅 알고리즘을 설계하기 위하여 관련 응용분야에서 그 유용성이 검증된 유전 알고리즘을 이용한다. 제안된 알고리즘은 wormhole 라우팅 방식을 사용하며, 교착상태를 없애기 위하여 하나의 물리적 채널을 공유하는 4개의 가상채널을 사용한다. 마지막으로, 시뮬레이션을 통하여 제안된 알고리즘이 기존의 다른 고장포용 라우팅 알고리즘보다 우수함을 증명한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.417-420
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• 2004

Ad hoc network는 유선 백본 없이 이동 노드들로만 구성된 네트워크로서 이동 노드들의 움직임이 빈번히 발생하기 때문에 네트워크의 안정성을 유지하기가 어렵다. 또한 중앙 집중화된 보안 기반구조가 아니기 때문에 보안 공격을 받기가 쉽고 노드들이 쉽게 손상될 수 있다. 기존의 보안 방법 중의 하나인 threshold cryptography는 키의 유지와 분배를 위한 효율적인 구조를 제공하였으나 라우팅의 오버헤드가 증가하였고, 네트워크 전역의 트래픽이 증가되었다. 게다가 서비스 거부 공격과 wormhole과 같은 공격은 ARP 또는 IP spoofing을 통하여 쉽게 받을 수 있다. 본 논문에서는 threshold cryptography에 의해 야기되는 오버헤드를 줄이고 노드간의 인증된 패킷 전달을 돕기 위한 새로운 접근 방법을 제안한다.