• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1019-1022
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• 2005

본 논문에서는 현재 활발한 연구개발이 이루어지고 있는 유비쿼터스 컴퓨팅, 센서 네트워크 기술을 적용한 무인 감시/추적 시스템을 제시한다. 본 논문의 무인 감시/추적 시스템은 센서네트워크 기술, 다중센서 융합에 의한 탐지 및 위치 인식기술, 무인 감시/추적 알고리즘으로 구성되어 있다. 센서네트워크는 센싱 데이터를 실시간으로 전송하기 위해 노드의 주소를 기반으로 하는 계층적 멀티홉 라우팅 기법을 제안하였다. 침입자와 추적자의 위치 인식은 자기센서 및 초음파센서를 가진 센서모듈들로부터 얻어진 센싱 정보를 융합하고, 이를 확률적으로 침입자 및 추적자의 위치를 결정하는 Particle Filter를 적용한 위치인식 알고리즘을 통해 이루어진다. 추적 알고리즘은 무인 자율 추적을 위해 이동벡터에 기반한 알고리즘이다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.138-138
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• 2020

본 연구에서는 우리나라에서 발생하는 무유출량을 고려하는 확률기반 격자형 수문 모형을 용담댐 유역에 구축하였다. 용담댐 유역은 무유출량이 종종 나타나는 간혈하천 (Ephemeral catchment) 유역으로 우리나라의 많은 유역들이 여기에 해당한다. 격자형 수문 모형의 구축을 위하여 Sacramento Soil Moisture Accounting Model (SAC-SMA) 유출 모형을 사용하여 라우팅 모형과 결합하였다. 무유출량을 표현하기 위해서 본 연구에서는 검열된 오류 모형 (censoring error model)을 사용하였다. 구축한 오류 모형과 기존에 많이 사용되는 정규화된 오류 모형의 비교를 하였으며 이를 통하여 본 연구에서 구축한 모형의 적합성을 평가하였다. 결과적으로 본 연구에서 구축한 두 개의 모형이 둘 다 신뢰할 만한 결과를 보여주지만 검열된 오류 모형이 더 적합한 결과를 보여주며 무유출의 빈도 증가에 따라 효율이 증가하는 것을 보여 준다. 그리고 기존의 방법론은 확률 기반의 유출량의 표현에 있어서 0 이하의 음수값을 표현하여 현실적이지 못한 수문 모델링을 표현한다. 따라서 본 연구에서 얻어진 결과는 간헐하천 유역에 대한 고려가 우리나라에 수문 모델 구축에 있어서 필요하다는 것을 의미한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.140-147
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• 2001

In this paper, we propose a scheme of calculating resources\` costs for precomputation in QoS routing schemes. This scheme is effective in respect to the g1oba1 network utilization and the balanced use of network resources. We also propose a QoS routing scheme for transit and intra traffic in a large scale of domain-based network. For a domain in the network, the routing scheme first precomputes multiple paths between all pairs of ingress and egress border routers while considering balancing of the expected load and then selects paths with the probability of path selection. We, therefore, expect that the paths are better than any other paths in respect to reserving the network resources on paths. The routing scheme combines inter and intra domain routings seamlessly and uses the same cost calculation scheme. And for analysis of a load balancing cost calculation proposed a simulation is done.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.59-68
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• 2004

Thanks to the development of microelectromechanical systems(MEMS), wireless communication technology and microsensor technology, it was Possible to manufacture a very small and low costdata acquisition node with sensing function, processing function, wireless communication function and battery. Thus sensor networks begin to be prevailed. The sensor network is a spontaneous system which sets up automatically routing paths and transmits asignificant data to the destination. Sensor nodes requires low-power operation because most of them use a battery as operating power. Sensor nodes transmit a sensing data to the destination. Moreover, they play a router. In fact, because the later consumes more energy than the former, the low-power routing is very important. Sensor networks don't have a routing standard unlike general wireless Ad-hoc networks. So This paper proposes a low-power routing method for anting to sensor networks. It is based on AODV and adapts a method to drop probably RREQ depending on remaining power. We examined it through simulations. From simulation results, we could confirm to reduce power consumption about $10-20\%$ and distribute equally power consumption among nodes.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.223-225
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• 2005

센서네트워크에서 이동물체의 경로 추적과 같이 실시간으로 패킷이 목적노드에 도착하여야 데이터가 유효한 응용의 경우에는 패킷 전송의 실시간을 보장할 수 있는 전송경로설정이 필요하다. 본 논문에서는 패킷을 전송하는데 있어서 지연시간을 증가시키는 요소인 혼잡상황과 낮은 링크 퀄리티를 가지는 경로를 회피함으로 전송지연시간을 최소로 줄이는 전송경로 설정 기법을 제안한다 네트워크의 위상에 따라 노드마다 다른 양상을 보이는 채널 부하도를 효과적으로 측정하고 네트워크의 혼잡상황을 판단하는 기준으로 삼는다. 이와 함께 링크의 전송 성공률을 이용하여 이웃 노드들의 전송경로 선택의 적합도를 계산하고 확률적으로 경로를 선택한다.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.357-364
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• 2014

The first mission for the IoT based hyper-connectivity communication is developing a device-to-device communication technique in infra-less low-power and lossy networks. In a low-power and lossy wireless network, IoT devices and routers cannot keep the original path toward the destination since they have the limited memory. Different from the previous light-weight routing protocols focusing on the reduction of the control messages, the proposed scheme provides the light-weight IPv6 address auto-configuration, IPv6 neighbor discovery and routing protocol in a IoT capable infra-less wireless networks with the bloom filer and enhanced rank concepts. And for the first time we evaluate our proposed scheme based on the modeling of various probability distributions in the IoT environments with the lossy wireless link. Specifically, the proposed enhanced RPL based light-weight routing protocol improves the robustness with the multi-paths locally established based on the enhanced rank concepts even though lossy wireless links are existed. We showed the improvements of the proposed scheme up to 40% than the RPL based protocol.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.68-76
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• 2008

It is difficult to maintain mutes in the mobile ad hoc network (MANET) due to the high probability of disconnected routes break by frequent change of topology. The links can have the different reliability about data transmission due to these characteristics. Hence a measure which can evaluate this reliability and a algorithm which reflects this are required. In this paper, we propose routing algorithm based on reliability about transmission. First the bayesian inference which infers the hypothesis by past information is considered to obtain the link's transmission reliability. The other is that the link-based reliability estimation model which considers each link's reliability additionally is proposed while the standard uses only Dijkstra's shortest path algorithm. the simulation results using NS-2 show that the performance of proposed algorithm is superior to the standard OLSR in terms of throughput and stability.

• Journal of Korea Multimedia Society
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• v.16 no.9
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• pp.1077-1088
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• 2013

As broadcasting is the process that a node sends a packet to all nodes in the network. it is basic process used for discovering of a routes to a node and disseminating of control information message in Mobile Ad hoc NETwork (MANET). In this paper, we propose dynamically adjusted probabilistic mechanism based on distance ratio and node density for broadcasting in MANETs. The distance ratio can be calculated as the ratio of the radio strength length to the distance from sender of a node, and node density can be get from 1-hop nodes of neighbours. A mobile node receiving broadcast packets determines the probability of rebroadcasting considering distance ratio and node density of itself. Rebroadcast probability will be set as low value to a node which is located in nearby area of sender and has high 1-hop node density, So it reduces packets transmission caused by the early die-out of rebroadcast packets. Compared with the simple flooding and fixed probabilistic flooding by simulation, our approach shows better performances results. Proposed algorithm can reduce the rebroadcast packet delivery more than 30% without scanting reachability, where as it shows up to 96% reachability compared with flooding.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.4 s.346
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• pp.22-30
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• 2006

In this paper, the goal of our proposed algorithm is to reduce link -failure and route failure caused by dead nodes which consume all of the battery life. I propose an algorithm which provides a ability of changing mutes to neighbor nodes before some of intermediate nodes be shutting don to get the stable route maintenance. To achieve this goal, The proposed routing algerian uses additional new messages to check energy status for monitoring energy of neighbor nodes and to change the path to a neighbor node. From extensive simulations, results show that possibility of cut-offs and time-delay cause of packet-loss have been decreased and also the improvement of transmission effectiveness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1427-1433
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• 2003

This paper presents the routing and wavelength and timeslot assignment problems for a circuit-switched time division multiplexed (TDM) wavelength-routed networks. In this paper, we propose an efficient distributed control protocol for establishing lightpath dynamically. The protocol uses backward reservation to reduce the chance of blocking. We use aggressive reservation method with usable multiple channels and select only one in multiple channel. We show through simulation that the proposed protocol improves the success rate in TDM-based lightpath establishment and the proposed aggressive reservation method improve blocking probability with appropriate reservation channel count.