• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.259-266
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• 2005

Recently data centric routing or application dependent routing protocols are emerged in mobile ad hoc networks. In this paper, we propose a routing method for query processing in MANET(Mobile Ad hoc NETwork) environment, called road-based query routing, with consideration on real time traffic information of large number of vehicles. In particular, we focus on the method that process arrival time dependent shortest path query in MANET without a central server on the road networks. The main idea of our approach lies in a routing message that includes query predicates based on the road connectivity and on data gathering method in real time from vehicles on the road by ad-hoc network. We unify route discovery phase and data delivery(query processing) phase in our mechanism and reduce unnecessary flooding messages by pruning mobile nodes which are not on the same or neighboring road segments. In order to evaluate the performances of the proposed method, we established a model of road networks and mobile nodes which travel along the roads. The measurement factor is the number of nodes to whom route request is propagated according to each pruning strategy. Simulation result shows that road information is a dominant factor to reduce the number of messages.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.454-461
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• 2005

Car navigation system which is killer application fuses map management techniques into CPS techniques. Even if the existing navigation systems are designed for the shortest path, they are not able to cope efficiently with the change of the traffic flow and the bottleneck point of road. Therefore, it is necessary to find out shortest path algorithm based on time instead of distance which takes traffic information into consideration. In this paper, we propose a optimal path search algorithm based on the traffic information. More precisely. we introduce the system architecture for finding out optimal paths, and the limitations of the existing shortest path search algorithm are also analyzed. And then, we propose a new algorithm for finding out optimal path to make good use of the orientation of the collected traffic information.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.724-727
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• 2003

유무선 대체 및 통합시대를 맞아 유무선간 균형있는 발전을 위해 유럽 둥 주요국가에서는 이동전화 시장에 MVNO, 이동전화 번호이동성, 재판매 제도 등을 도입하여 실행하고 있다. 이처럼 유무선간 비대칭 규제를 해소하기 위해서 상대적으로 규제가 약한 이동전화 시장에 유선에 적용되는 규제를 적용하는 것이 유무선간 대칭규제를 위한 방안이 될 수 있다. 따라서 본 고에서는 이러한 입장에서 이동전화 시장을 활성화시키기 위한 정책들을 살펴보고 이를 이미 실행하고 있는 외국의 사례를 통해 이들 정책의 도입효과 등을 살펴보고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.496-498
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• 2004

무선 ad-hoc 네트워크는 이동 노드만으로 구성된 자율적이고 수평적인 네트워크이다. 무선 ad-hoc 네트워크에서의 라우팅 프로토콜은 table driven 방식과 on-demand 방식으로 나뉘는데, 이 중 라우팅 메시지의 오버헤드가 비교적 적은 on-demand 방식이 주로 사용되고 있다. 이 프로토콜은 경로를 찾기 위해서 경로 요청 메시지를 브로드캐스팅 하는데, 경로 요청 메시지는 네트워크 전체로 확산되기 때문에 이를 이용한 공격이 가능하다 공격자는 연속적으로 경로 요청 메시지를 보냄으로써 패킷 충돌과 네트워크 큐오버플로우 등의 장애를 일으켜 정상적인 메시지나 데이터의 전송을 방해할 수 있다. 본 논문에서는 기존의 라우팅 프로토콜에 별도의 인증 절차 없이 경로 요청 패킷의 확산을 이용한 공격을 막는 방법을 제안하고자 한다. 각각의 노드는 경로 요청 메시지의 시작 주소와 수신 시간을 경로 요청 테이블을 이용해 관리함으로써 정상적인 경로 요청 패킷과 공격자의 경로 요청 패킷을 구분한다. 수신된 경로 요청 패킷이 공격자의 패킷이라고 판단된 경우, 공격자의 패킷을 이웃 노드에 전달하지 않음으로써 전체 네트워크에 가해지는 공격을 막을 수 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.565-569
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• 2007

To find optimal path is killer application in the telematics system. The shortest path of conventional system, however, isn't always optimal path. That is, the path with minimum travelling time could be defined as optimal path in the road networks. There are techniques and algorithms for finding optimal path. Hierarchical path algorithm categorizes road networks into major layer and minor layer so that the performance of operational time increases. The path searched is accurate as much as optimal path. At above 2 system, a method to allocate minor roads to major road region influences the performance extremely. This paper proposes methods to determine search space for selecting major roads in the hierarchical path algorithm. In addition, methods which apply the proposed methods to hierarchical route algorithm is presented.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.6
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• pp.842-849
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• 2018

This research suggests the development of simulator for a Simulation Test of a moving object's path generation and following. There are many kinds of moving objects in weapon systems, such as vehicles, missiles, robots and so on. So need tests of moving simulations during development process of weapon systems. To simulate a moving object, need an flexible path. So this report suggests a $B\acute{e}zier$ curve algorithm for generation of smooth curve path. And when new developments of weapon systems are started, many kinds of simulators are created. But, these simulators are not reused in other project because there are different kinds of development environment. So need to allow users to add specific features, And this report suggests using Dynamic Link Library(DLL).

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.15-20
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• 2011

The pine wilt disease is one of the most serious forest diseases that kill the pine trees, and the study on the invasion and movement of the pine wood nematode within the tree is very important for understanding the inhabitation of pine wood nematode. In this relation, the microscopic observation was carried out to study the place of inhabitation and movement of pine wood nematode within the infested wood. In result, the rays were mainly infested by pine wood nematode and showed dark discoloration due to their necrosis in cross, radial and tangential surface. Also, the intensive damage was found in the resin canals. On the other hand, some traumatic resin canals in tangential band were identified in the sapwood near the cambium. In the ray, the pine wood nematode occurred more commonly in the ray parenchyma cell and fusiform ray with horizontal resin canal than in the ray tracheid and uniseriate ray without horizontal resin canal, respectively. The pine wood nematode was thought to move from ray to tracheid through the large natural opening, window-like pit, in the cross-field, neither through the small natural opening, bordered pit, in the tracheid nor through the tracheid wall by creating a bore hole.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.2
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• pp.4-10
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• 1993

In mobile radio communication, propagation paths are time or spacial varying because of the motion of mobile unit. The propagation path loss not only involves frequency and distance but also the antenna height at both the base station and the mobile unit, terrain configuration, and the man made en- vironment. Thhese additional factors make the prediction of propagation path loss of mobile radio signals more difficult. In this paper, it is measured field strenght of mobile radio signals in Daejeon and Seoul area, also calculated local median, 500m sample mean, and stadard deviation. As the result of analysis, it can be seen that propagation path loss of measured data is similiar to predicted field strength, especially local median is dependent upon base antenna height, terrain configuration and the man-made environment. The standard deviation has been noted to lie between 2 and 10 dBuV.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.77-86
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• 2010

The study developed physical distribution channel choice models reflecting decision making of the firms and studied how choice decision factors influence selection of distribution channel. The distribution channel survey data in Korea was used to do empirical study. As a choice set, distribution channels were classified into two main choice channels: direct and indirect channels. In addition, indirect channels were classified into other three channels according to the type of intermediate point: distribution center, wholesale store, and agency. This study developed choice models by applying both binary and multinomial logit model with various set of factors. The results showed that the developed logit models seemingly reflect distribution channel choice behaviors. The hypothesis tests on how each factor influences choice of distribution channel were performed and discussed as well.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1163-1166
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• 2007

핸드오버가 발생하는 이동망 환경에서 주요 이슈 중 하나는 핸드오버 후 MN(Mobile Node)의 트래픽이 전송될 새로운 경로 상에 자원 재예약을 위한 지연 시간을 최소화하는 것이다. 이를 위해, 데이터 전달 경로가 변경된 경로에서만 자원예약 시그널링이 이루어지도록 CRN(Crossover Node)을 발견하는 것이 중요하다. 이동망 환경에서 자원 재예약을 위한 CRN은 SID(Session ID)를 이용하여 발견될 수 있다. 그러나 HMIPv6 네트워크에서 MAP(Mobility Anchor Point)과 HA(Home Agent)간 군집(Aggregate) 자원 예약이 이루어진 경우에서는 SID를 이용하여 CRN을 발견할 수 없다. 왜냐하면, MN의 핸드오버 후, 종단간 SID는 동일할지라도 이전 MAP과 HA간 설립된 세션의 군집 SID가 새로운 MAP과 HA간 설립된 세션의 군집 SID와 다르기 때문이다. 이에, 본 논문에서는 HMIPv6 네트워크에서의 CRN 발견방안을 제안한다. 제안하는 방안에서는 시그널링 메시지에 이전 군집 세션 정보를 포함하여 전달함으로서 시그널링 메시지가 목적지까지 도달하기 전에 CRN이 발견될 수 있도록 하였다. 제안하는 방안은 군집 자원예약이 갖는 시그널링 및 플로우별 상태 정보 감소 효과를 그대로 유지하면서, MN의 핸드오버 후, 자원 재예약을 위한 지연 시간을 단축시킴으로서 통신 성능을 향상 시킬 수 있을 것으로 기대된다.