• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.118-120
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• 2005

센서 노드의 자원 제약성 때문에 센서네트워크에서 키 설정 하는 것은 어렵다. 특히 기존에 제안된 공개키 암호 방식 키 설정 기법은 센서 네트워크에 적용이 불가능하며 이를 해결하기 위한 대칭키 암호 방식을 이용한 키 설정 기법들이 제안되어왔다. 대칭키 암호 방식을 이용한 여러 가지 키 설정 기법 중 랜덤-키 사전분배 기법 [2]과 랜덤 Pair-wise 키 사전 분배기법[1]에 대해 알아보고 문제점을 지적한다.

• Journal of Korea Multimedia Society
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• v.9 no.3
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• pp.333-341
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• 2006

Recently, Random Constant worm is increasing The worm retards the availability of the overall network by exhausting resources such as CPU resource and network bandwidth, and damages to an uninfected system as well as an infected system. This paper analyzes the Power-Law network which possesses the preferential characteristics to restrain the worm from spreading. Moreover, this paper suggests the model which dynamically controls the spread of the worm using information about depth distribution of the delivery node which can be seen commonly in such network. It has also verified that the load for each node was minimized at the optimal depth to effectively restrain the spread of the worm by a simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.603-606
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• 2019

In this paper, we propose a slotted-ALOHA-based random access protocol and derive the optimal number of random slots that maximize channel throughput when multiple energy harvesting sensor devices perform random access in wireless-powered sensor networks (WPSN). Throughput numerical analysis, we prove that the throughput has a concavity with respect to the number of random slots and obtain the optimal number of slots. Simulation results show that the throughput of the proposed slotted ALOHA-based random access protocol is maximize when the derived optimal number of slots is employed in the considered WPSN.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.133-135
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• 2005

인터넷에서 일어나는 침해사고 중에서 웜에 의한 피해가 가장 심각하다. 2001 년 Code Red 웜의 출현과 2003 년 SQL Slammer 웜의 출현 이후로 웜에 감염된 이후에 행동 양상을 탐지하여 대응하는 것은 웜의 피해를 최소화 하기에는 역부족이다. 웜에 의해서 감염이 되기 이전에 웜을 탐지하여 조기에 대처하는 것이 무엇보다 중요하다. 또한 이미 알려져 있는 웜에 대한 행동양상을 이용한 웜의 탐지는 신종 웜의 출현 주기가 급격히 짧아지는 현실에 능동적으로 대처할 수 없다. 현재까지 발생한 인터넷 웜은 감염시킬 대상을 선택함에 있어서 랜덤 생성기를 사용하였으며 향후 나타날 웜도 빠른 확산과 자신의 위치를 드러내지 않기 위해 랜덤 스케닝 방식을 사용할 것이다. 본 연구는 네트워크의 연결들을 행렬로 표현하고, 이 행렬의 랭크(rank)값을 구하여 랜덤성 체크를 하는 방식으로, 웜으로 인한 트래픽에서 발생하는 랜덤성을 탐지할 수 있도록 하였다. 이 방법은 네트워크에서 알려지지 않은 신종 웜을 탐지하도록 하므로, 웜에의한 확산을 조기 탐지할 수 있게 하고, 더불어 웜의 피해를 최소화 하는 것을 목적으로 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1313-1320
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• 2015

In this paper, we propose a user detection technique based on parallel orthogonal matching pursuit (POMP) for uplink multi-user random access networks (RANs) with a number of users and receiver antennas. In general RANs, it is difficult to estimate the number of users simultaneously transmitting packets at the receiver because users with data send the data without grant of BS. In this paper, therefore, we modify the original POMP for the RAN and evaluate its performances through extensive computer simulations. Simulation results show that the proposed POMP can effectively detect activated users more than about 2%~8% compared with the conventional OMP in RANs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.175-182
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• 2018

As Internet of things with a large number of nodes emerges, wireless-power communication networks (WPCN) based on a random access protocol needs to be investigated. In the random access-based WPCN, a terminal accessing later in given random access (RA) slots can harvest more energy before transmission and thus can transmit data with higher power and achieve higher throughput if the access is successful. On the basis of this property, the proposed random access control protocol gives the terminals priority and distinguishes the RA slots according to the priority level, so that a near terminal with access point allows to access preferentially other than a remote terminal. This operation decreases the throughput of near terminal and increases the throughput of remote terminal, and then, the doubly near-far problem in WPCN is resolved and the user fairness is improved. Results show that the proposed random access control improves both channel throughput and user fairness according to the priority level.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.917-922
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• 2004

Mobile ad hoc networks (MANETs) are networks of mobile nodes that have no fixed network infrastructure. Since the mobile node's location changes frequently, it is an attractive area to maintain the node's location efficiently. In this paper, we present an adaptive randomized database group (ARDG) scheme to manage the mobile nodes mobility in MHANETs. The proposed scheme stores the network nodes' location in location databases to manage the nodes' mobility. When a mobile node changes its location or needs a node's location, the node randomly select some databases to update or que교 the location information. The number of the selected databases is fixed in the case of querying while the number of the databases is determined according to the node's popularity in the case of updating. We evaluated the performance of the proposed scheme using an analytical model, and compared the performance with that of the conventional randomized database group (RDG) scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2014-2021
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• 2015

Opportunistic interference alignment (OIA) has been proposed for multi-cell random access networks (RAN), which minimizes the generating interference to neighboring RANs and yields better performance compared with the conventional techniques. The OIA for RANs considers both physical (PHY) and medium access control (MAC) layers. In this paper, we introduce a protocol of which each user maximizes the transmit signal regardless of the generating interference to neighboring RANs, contrary to the OIA technique. In addition, we compare the performance of the signal-maximization technique with the OIA technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.911-916
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• 2016

The nearest-neighbor multihop routing with/without infrastructure support is known to achieve the optimal capacity scaling in a large packet-erasure network in which multiple wireless nodes and relay stations are regularly placed and packets are erased with a certain probability. In this paper, a throughput scaling law is shown for an infrastructure-supported erasure network where wireless nodes are randomly distributed, which is a more feasible scenario. We use an exponential decay model to suitably model an erasure probability. To achieve high throughput in hybrid random erasure networks, the multihop routing via highway using the percolation theory is proposed and the corresponding throughput scaling is derived. As a main result, the proposed percolation highway based routing scheme achieves the same throughput scaling as the nearest-neighbor multihop case in hybrid regular erasure networks. That is, it is shown that no performance loss occurs even when nodes are randomly distributed.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.789-792
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• 2000

차세대 이동통신 시스템의 이용자와 네트워크간 이용자 익명성을 보장하고, 이용자와 네트워크가 상대 실체를 안전하게 상호 인증할 수 있는 공개키 암호 방식에 기반한 개선된 인증 및 키합의 프로토콜을 제안한다. 이 프로토콜은 이용자와 네트워크는 이용자의 고유신분과 세션별로 변하는 랜덤수를 입력으로 하여 임시신분 정보를 생성 및 상호 공유하고, 네트워크는 초기에 이용자의 신분을 확인하며, 임시신분 정보는 이용자와 네트워크가 상호 선택한 랜덤 수에 따라 세션별로 갱신되므로 무선 접속 구간 상에 익명성을 보장하고 기존의 방식에 비교하여 보다 강화된 안전성을 보장한다.