• 한국통신학회논문지
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• 제28권7A호
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• pp.451-466
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• 2003

Untethered nodes in mobile ad-hoc networks strongly depend on the efficient use of their batteries. In this paper, we propose a new metric, the drain rate, to forecast the lifetime of nodes according to current traffic conditions. This metric is combined with the value of the remaining battery capacity to determine which nodes can be part of an active route. We describe new route selection mechanisms for MANET routing protocols, which we call the Minimum Drain Rate (MDR) and the Conditional Minimum Drain Rate (CMDR). MDR extends nodal battery life and the duration of paths, while CMDR also minimizes the total transmission power consumed per packet. Using the ns-2 simulator and the dynamic source routing (DSR) protocol, we compare MDR and CMDR against prior proposals for power-aware routing and show that using the drain rate for power-aware route selection offers superior performance results.

• 한국항행학회논문지
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• 제28권2호
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• pp.163-171
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• 2024

기존 항공교통관리 (ATM; air traffic management) 체계에서는 항공기 위치 및 세부 운항 정보와 함께 항공기 운항의 안전성을 보장하기 위하여 다양한 형태의 안전 경고 기능을 항적 정보를 기반으로 함께 제공한다. 도심항공교통(UAM; urban air mobility)을 대상으로 한 도심항공교통관리(UATM; urban air traffic management) 체계에서도 UAM 운항의 안전성을 보장하기 위한 안전 경고 기능이 제공되어야 한다. UAM의 운항 환경을 고려하였을 때 기존 ATM 체계에서 준용하는 수준과 동등한 또는 더 높은 수준의 안전 경고 기능이 제공되어야 한다. 본 연구는 UAM 도입 및 상용화 단계에 앞서 기존 ATM 체계에서 제공하는 안전 경고 기능과 다른 새로운 UATM 체계의 안전 경고 기능을 제시하고자 한다. UAM의 경로 이탈 발생 시 제공되어야 하는 안전 경고 기능을 중심으로 연구를 진행하였으며 접근 단계에서 적용되는 APM (approach path monitor) 및 순항 단계에서 적용되는 RAM (route adherence monitoring) 두 가지 부분으로 나누어 안전 경고 기능 구축을 진행하였다.

• 한국실내디자인학회논문집
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• 제14권3호
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• pp.147-155
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• 2005

As multiplex theaters are increasing rapidly in number, concerns over the evacuation process in case of fire emergency are also increasing. The study investigates the users' awareness and recognition of evacuation route by the method of questionnaire, and analyzes the users' behavior in choosing the route by the simulation program called Simulex. Among others, findings indicate a vast majority of the users are unaware of the proper route in the emergency, yet anticipate to evacuate by it, instead of the entry/exit route that they are familiar with. This aspect, however, can be useful to provide the proper route of evacuation for the users, if an appropriate information is given that the entry/exit route is also used as an emergency egress. The simulation shows heavy congestion at the closer evacuation route from the exit, and distinctly less traffic at the farther means of egress. Based on this natural phenomenon, it is suggested that the emergency stair should be nearby and aligned with the exit from auditorium. Although the present building regulation only requires a minimum dimension at each route, there is a need to widen the passageway that is likely to be recognized easily and subsequently overcrowded in case of fire emergency.

• ETRI Journal
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• 제20권2호
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• pp.171-191
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• 1998

In this paper, we propose a new heuristic design algorithm for the virtual path (VP)-based ATM network with multiple traffic classes, in which QoS constraints associated with traffic class are taken into account. The minimum bandwidth of VP required to carry given amount of traffic is obtained by utilizing an equivalent bandwidth concept, and the route of each VP is placed so that the network cost is minimized while the QoS requirement is fulfilled To evaluate our design algorithm, we consider two kinds of traffic: voice traffic as low speed service and still picture traffic as high speed service. Through numerical examples, we demonstrate that our design method can achieve an efficient use of network resources, which results in providing a cost-effective VP-based ATM network.

• Journal of Communications and Networks
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• 제7권3호
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• pp.325-336
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• 2005

Mobile ad hoc networks (MANET) are composed of moving wireless hosts which, within range of each other, form wireless networks. For communication to occur between hosts that are not within each other's range, routes involving intermediate nodes must be established; however, since the hosts may be in motion, a host that was part of a route may move away from its upstream and downstream partners, thus breaking the route. In this paper, we propose anticipated route maintenance (ARM) protocol with two extensions to route discovery based routing scheme: Extend the route when nodes on a link move apart from each other and they have common neighbor that can be 'inserted' in the path, and shrink route when a node discovers that one of its neighbor which is not the next hop is also on the same route several hops later on. By utilizing only local geographic information (now a part of some route finding algorithms), a host can anticipate its neighbor's departure and, if other hosts are available, choose a host to bridge the gap, keeping the path connected. We present a distributed algorithm that anticipates route failure and performs preventative route maintenance using location information to increase a route lifespan. The benefits are that this reduces the need to find new routes (which is very expensive) and prevents interruptions in service. As the density of nodes increases, the chance to successfully utilize our route maintenance approach increases, and so does the savings. We have compared the performance of two protocols, pure dynamic source routing (DSR) protocol and DSR with ARM. The simulation results show how ARM improves the functionality of DSR by preventing the links in the route from breaking. Packets delivery ratio could be increased using ARM and achieved approximately $\100%$ improvement. The simulations clarify also how ARM shows a noticeable improvement in dropped packets and links stability over DSR, even though there is more traffic and channel overhead in ARM.

• 한국항해항만학회지
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• 제31권3호
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• pp.173-178
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• 2007

해상교통관리 방법 중에서 국내외적으로 혼잡한 해역에서의 해상교통 흐름을 정류하여 통항선박의 해상교통 안전성을 향상시키는 방법 중 주로 이용되고 있는 것은 항로 설정 및 통항분리대의 설정이다. 항로 및 통항분리대의 설정 시 지침이 되는 설계지침 가운데 국내외적으로 항로 설계지침은 존재하지만 통항분리대에 대한 설계지침에 대한 언급은 어느 문헌에도 없어 전문가의 주관적 판단에 의하여 설정이 되고 있는 실정이다. 현재까지 통항분리대의 설정 시 해양사고의 감소효과에 대한 연구는 다소 있지만, 통항분리대의 설계지침에 대한 연구는 없다. 본 연구는 통항선박의 안전을 위하여 설정되는 통항분리제도에 대한 설계지침을 선박 운항자의 관점에서 본 정량적 수치로 제공하고자 한다. 특히 통항분리대는 많은 선박의 통항을 분리하기 위한 제도이기 때문에 통항하는 선박의 교통용량을 고려하여 설계하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 춘계학술대회 논문집
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• pp.189-195
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• 2004

최근 우리나라의 해상에서는 육상과 섬 또는 섬과 섬을 연결하는 해상교량이 건설 중이거나 건설 예정이다. 선박의 통항로에 해상교량이 설치되면 선박통항의 안전성은 당연히 위해가 되지만, 국가 및 지역의 경제발전을 위해서 설치가 불가피한 경우도 있다. 이러한 선박통항 안전성과 지역 경제성 간에 트레이트 오프(trade off) 관계가 있는 해상교량을 설치하기 위해서는, 선박통항 안전성 면에서 고려되어야 할 요소를 해상교통공학적인 측면에서 조사ㆍ검토하고, 그 요소들을 평가하여 교통 흐름을 원활하게 하고 해역의 안전을 보장하기 위한 것이 이 연구의 목적이다. 주교각폭이 넓은 교량을 설치하면 선박의 통항 안전성 측면에서는 유리하겠지만, 지형적인 영향이나 경제성 측면 때문에 충분한 항로폭을 확보할 수 없는 경우도 있을 수 있다. 따라서 이 논문에서는 해상교통류 시뮬레이션 기법을 이용하여 선박통항의 안전성을 확보하기 위한 통항량 규제와 같은 대안을 검토한다.

• 한국항만학회지
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• 제7권2호
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• pp.37-60
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• 1993

Because of the rapid growing traffic volumes of cargo, especially between Seoul and Inchon, and lack of investment into transport infrastructure in the past, in Kyong-in area have suffered from the serious traffic congestion in the public-road and the express-way network, But the further expansion of the traffic volume in near future is difficult due to burden of the higher expansion of the traffic volume in near future is difficult due to burden of the higher construction cost. Although the traffic congestion on the Kyung-in railway, is not very serious comparing with the road sector, the shortage of capacity on some main lines becomes emerged as a problem as railway traffic has increased. Unlike these two modes, the water transport, which has been paid relatively less attention for commodity transport in Kyong-in area, has not any constaint in this respect. Han river has been used as a water transport route in Chosun Dynasty which is called Cho-wun. This paper therefore aims to propose the availability of Han river as the alternative water transportation mode, in order to decrease the congestion between Seoul-Inchon by considering the construction of Kyong-in artificial water channel in near future. In this paper, we investigate the availability of Nanji-do as the physical distribution depot connecting with the circulation express way in the national capital distribution depot connecting with the circulation express way in the national capital. We also estimate the traffic volume by using the push-barge carrier (300DWT) in the same channel through the simulation under some assumptions such as ship's turnaround time, speed, etc.

• 한국IT서비스학회지
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• 제17권4호
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• pp.85-100
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• 2018

In this study, we formulated rational criteria to efficiently provide traffic information services via a crafted approach. By utilizing this, we presented a detailed traffic information service providing method that can overcome the limitations of existing link unit information provision system. Three methodologies such as user survey, data mining, and KHCM (Korea Highway Capacity Manual) utilization method were applied to formulate a rational expression standard for traffic information service. Each method was designed to establish a quantitative criterion for various traffic conditions and to enable user-oriented traffic information service in consideration of the traffic principal/compatibility. Considering the results of each methodological analysis in a comprehensive manner, the basic expression standards for traffic information service was formulated. Then we presented improvements such as traffic condition step by road, speed range of traffic condition, expression term of traffic condition and so on. In order to complement the problems of the information provision system of the existing link unit based on the derived improvement criterion, we presented the detailed traffic information service provision method by using the traffic speed data of the second order. And we applied this to the two links of Daegu city. The method presented in this research can improve the quality of traffic information service. Not only it can be used for various fields such as optimal route search, traffic safety service and so on.

• 한국정보과학회논문지:정보통신
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• 제33권4호
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• pp.299-309
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• 2006

Ad hoc 환경에서 사용되는 On-demand 방식인 AODV 라우팅 프로토콜은 경로를 찾기 위하여 노드들이 가지고 있는 라우팅 테이블을 우선 검사하고, 만약 적합한 경로가 존재하지 않거나 유효하지 않은 경로, 또는 중간노드에서 경로손실이 발생하였을 경우 Route Discovery Process(RDP)를 수행하여 새로운 경로를 찾게 된다. 하지만 중 / 대형 Ad hoc 환경에서 이러한 RDP의 증가는 네트워크 성능의 저하를 초래한다. 본 논문에서는 경로설정을 위해 사용되는 AODV 라우팅 프로토콜에 Zone 개념을 도입한 AOZDV(Ad hoc On-demand Zone and Distance-Vector Routing Protocol)를 제안한다. AOZDV는 노드의 트래픽과 전력정보를 활용하여 소스 / 목적지 노드에 Zone을 형성하고, Zone 내부에서의 라우팅은 Destination-Vector Table을 활용하는 기법으로서, 시뮬레이션을 통해 AOZDV 가 기존의 라우팅 프로토콜들에 비해 노드들의 이동성으로 인해 발생하는 경로손실 및 RDP 가 감소함을 확인할 수 있었다.