• 대한안전경영과학회지
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• 제13권1호
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• pp.127-131
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• 2011

Even if there are no causing factors such as car crash and road works, traffic congestion come from traffic growth on the road. In this case, estimation of traffic flow helps find the solution of traffic congestion problem. In this paper, we present a optimization model which used on traffic equilibrium problem and studied the problem of inverting shortest path sets for complex traffic system. And we also develop pivotal decomposition algorithm for reliability function of complex traffic system. Several examples are illustrated.

• 한국콘텐츠학회논문지
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• 제10권12호
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• pp.254-266
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• 2010

본 연구는 천안시를 대상으로 도시교통문제를 다루었다. 본 연구는 문헌조사와 실증조사를 병행하였다. 회수된 설문지 394부를 SPSS 15.0버전으로 빈도분석을 실시하였다. 천안시의 도시교통문제는 출 퇴근시의 교통체증 현상, 대중교통의 불편, 주차문제, 자동차로 인한 대기오염, 교통사고로 인한 불안 등을 들 수 있다. 교통문제의 개선방안으로는, 첫째, 합리적 교통수요의 관리에 따른 교통체계의 개선방안이 마련되어야 한다. 둘째, 천안시는 대중교통의 이용대상인 대학생이 많으므로 대학생을 대상으로 할인을 적용 대중교통 이용률을 높여야 한다. 셋째, 대중교통중심체제의 강화 및 개선을 통한 교통체증의 해결이 필요하다. 넷째, 도로 등 교통시설의 공급확대, 가로망체계 정비 및 신호운영체계의 개선을 적극적으로 추진해 나가야 한다. 특히 천안에는 오래된 도로의 정비가 필요하고 도로망이 복잡하게 얽혀있는데 이를 간단하게 개선함으로써 보다 접근성이 좋아질 것이다. 다섯째, 주차문제의 해결과 이용자들의 교통질서 의식함양 등 선진 교통문화의 정착이 필요하다.

• ETRI Journal
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• 제5권2호
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• pp.17-28
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• 1983

This paper deals with the problem of optimally controlling traffic flows in urban transportation traffic networks. For this, a nonlinear discrete-time model of urban traffic network is first suggested in order to handle the phenomenon of traffic flows such as oversaturatedness and/or undersaturatedness. Then an optimal control problem is formulated and a hierarchical optimization technique is applied, which is based upon a prediction-type two-level method of Hirvonen and Hakkala.

• 한국경영과학회지
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• 제26권1호
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• pp.33-44
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• 2001

In this paper, we address a problem of traffic grooming and wavelength routing in all optical WDM ring networks. Given a traffic demand for each node pair, we should aggregate the traffic onto lightpaths between pairs of nodes to transport the demand, and set up the routing path for each lightpath with minimum number of wavelengths to be assigned to lightpaths. In this paper, we formulate our problem as a mixed Integer Programming model. Owing to the problem complexity, it is hard to find an optimal solution for our problem. hence, we develop a heuristic algorithm to solve our problem efficiently. From the computational experiments, we can find the proposed heuristic is very satisfactory in both the computation time and the solution quality generated.

• 한국컴퓨터정보학회논문지
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• 제20권7호
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• pp.33-40
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• 2015

The time slot assignment problem (TSAP) or Satellite Communications scheduling problem (SCSP) for a satellite performs $n{\times}n$ ground station data traffic switching has been known NP-hard problem. This paper suggests $O(n^2)$ time complexity algorithm for TSAP of a satellite that performs $n^2{\times}n^2$ ground station data traffic switching. This problem is more difficult than $n{\times}n$ TSAP as NP-hard problem. Firstly, we compute the average traffic for n-transponder's basic coverage zone and applies ground station exchange method that swap the ground stations until all of the transponders have a average value as possible. Nextly, we transform the D matrix to $D_{LB}$ traffic matrix that sum of rows and columns all of transponders have LB. Finally, we select the maximum traffic of row and column in $D_{LB}$, then decide the duration of kth switch mode to minimum traffic from selected values. The proposed algorithm can be get the optimal solution for experimental data.

• 한국경영과학회지
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• 제25권4호
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• pp.15-25
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• 2000

In this paper, we introduce a point-to-multipoint minimum cost flow problem with convex and demand splitting. A source node transmits the traffic along the tree that includes members of the point-to-multipoint connection. The traffic is replicated by the nodes only at branch points of the tree. In order to minimize the sum of arc costs, we assume that the traffic demand can be splitted and transmitted to destination nodes along different trees. If arc cost is linear, the problem would be a Steiner tree problem in networks eve though demand splitting is permitted. The problem would be applied in transmitting large volume of traffic from a serve to clients in Internet environments. Optimality conditions of the problem are presented in terms of fair tree routing. The proposed algorithm is a finite terminating algorithm for $\varepsilon$-optimal solution. convergence of the algorithm is obtained under monotonic condition and strict convexity of the cost function. Computational experiences are included.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.468-474
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• 2007

Korea's road traffic has been the important role of social and economic development, and it'll be a much more important in the future. But we require a far more efficient road traffic system to solve the problem of vehicle increases. So this paper is analyzed and researched both road traffic systems and road traffic safety, and hypothesized a solution to the problem by using small town's road traffic system demands as a good example. The road traffic system should harmonize around the structure of the town, and be related to the safety, By analyzing road traffic system, we can understand how importantly the traffic system is related with safety, efficiency and overall benefits for our community.

• Journal of information and communication convergence engineering
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• 제11권1호
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• pp.30-44
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• 2013

Traffic congestion has become a serious problem with the recent exponential increase in the number of vehicles. In urban areas, almost all traffic congestion occurs at intersections. One of the ways to solve this problem is road expansion, but it is difficult to realize in urban areas because of the high cost and long construction period. In such cases, traffic signal control is a reasonable method for reducing traffic jams. In an actual situation, the traffic flow changes randomly and its randomness makes the control of traffic signals difficult. A prediction of traffic jams is, therefore, necessary and effective for reducing traffic jams. In addition, an autonomous distributed (stand-alone) point control of each traffic light individually is better than the wide and/or line control of traffic lights from the perspective of real-time control. This paper describes a stochastic optimum control of crossroads and multi-way traffic signals. First, a stochastic model of traffic flows and traffic jams is constructed by using a Bayesian network. Secondly, the probabilistic distributions of the traffic flows are estimated by using a cellular automaton, and then the probabilistic distributions of traffic jams are predicted. Thirdly, optimum traffic signals of crossroads and multi-way intersection are searched by using a modified particle swarm optimization algorithm to realize real-time traffic control. Finally, simulations are carried out to confirm the effectiveness of the real-time stochastic optimum control of traffic signals.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.306-310
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• 2004

In this paper, we consider the Ring Loading Problem with integer demand splitting (RLP). The problem is given with a ring network, in which a required traffic requirement between each selected node pair must be routed on it. Each traffic requirement can be routed in both directions on the ring network while splitting each traffic requirement in two directions only by integer is allowed. The problem is to find an optimal routing of each traffic requirement which minimizes the capacity requirement. Here, the capacity requirement is defined as the maximum of traffic loads imposed on each link on the network. We formulate the problem as an integer program. By characterizing every extreme point solution to the LP relaxation of the formulation, we show that the optimal objective value of the LP relaxation is equal to p or p+0.5, where p is a nonnegative integer. We also show that the difference between the optimal objective value of RLP and that of the LP relaxation is at most 1. Therefore, we can verify that the optimal objective value of RLP is p+1 if that of the LP relaxation is p+0.5. On the other hand, we present a strengthened LP with size polynomially bounded by the input size, which provides enough information to determine if the optimal objective value of RLP is p or p+1.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.238-242
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• 2005

This paper considers a routing problem on a RPR(Resilient Packet Ring). The RPR is one of the ring-type data telecommunication network. Our major problem is to find an optimal routing algorithm for a given data traffic on the network under no splitting the traffic service, where the maximum load of a link is minimized. This paper characterizes the Minmax problem and develops two heuristic algorithms. By using the numerical comparison, we show that our heuristic algorithm is valuable for efficient routing the data traffic on a RPR.