• 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.

• 한국정보전자통신기술학회논문지
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• 제8권1호
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• pp.23-27
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• 2015

요즈음 교통사고를 줄이기 위하여 IT 기술을 이용한 교통사고 연구가 많이 진행되고 있다. 그러나, 뺑소니 교통사고 발생하면 가해차량을 현장에서 찾기가 매우 어렵다. 교통사고 조사 과학화를 위해서, RFID 기술 및 유비쿼터스 이론을 이용하여 효율적인 교통사고 예방 시스템을 구축하는 알고리즘을 제안하였다. 특별히, 본 논문에서는 시시각각 변화하는 따른 도로상황 및 날씨 조건에 변화에 따른 최적 교통안전 속도를 산출하는 모의실험을 하였다.

• 한국항해학회지
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• 제15권3호
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• pp.1-11
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• 1991

As increasing needs of marine transportation , world merchant fleet and ship's size were enlarged and it caused frequent disasters in human lives and natural environment. By the reason of the above, they started to establish the Vessel Traffic System (VTS) at the European coast in 1960' and most of advanced contries established and managed it to prevent the sea traffic accidents in these days. The concept of traffic control at sea can be divided into three types. First, the initial gathering of informations about ship's identity and movement etc.. Second, monitoring of the traffic flow and amendment of instructions. Third , organization and direction of ships by allocating routes and speeds. Where the goal of traffic control is safety of traffics and developing effectiveness of navigation channel, if traffic volume is less tan channel capacity then the above first or second level of control would be sufficient but if it is bigger than that , more positive policy of control should be adopted as same as third type of the above. In this paper where the strategy of VTS is focused on the control of traffic density to be spread equality, as possible , all over the navigation channels and also improvement of effectiveness , it suggests algorithm to assign the vessels to the channels with balanced traffic density , and other algorithms using D.P. to sequence the vessels assigned to one channel in optimum order which decreases the mean waiting time in sense of channel effectiveness with numerical examples.

• 한국통신학회논문지
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• 제25권9A호
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• pp.1299-1305
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• 2000

도래할 B-ISDN 환경하에서 중추적 역할을 할 ATM의 실현을 위해서는 다중매체의 통화유량을 최적하에 제어할 수 있는 방법이 제시되어야 한다. 그러나 다중매체 통화유량의 특성이 완전히 밝혀지지 못한 상태에서 ATM의 제어, 특히 최적한 폭주제어의 실현은 난제로 남아있다. 그러므로 본 논문에서는 다중매체 통화유량 모델을 시변비선형함수라 가정하고 이를 실시간 추정하기 위해 병렬로 연결된 3중의 신경망 모델을 제시하며 모의실험을 통해 시변비선형함수를 추정하여 ATM의 폭주제어에 이용될 수 있는 가능성을 보인다.

• 대한교통학회지
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• 제1권1호
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• pp.56-63
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• 1983

Intersection control has dual-purposes; increasing capacity and reducing delay. The primary concern of efficient intersection control under oversaturated condition as in Korea is to increase capacity. Prevailing intersection operation technique permits thru traffic to utilize left turn lane, because the intersection without left turn pocket has left turn signal interval. In this situation, it seems not to be valid to calculate capacity, delay, and signal timings by conventional methods. By critical lane technique, capacity increases as cycle length increases. However, when thru traffic utilize LT lane, the capacity varies according to LT volume, LT interval as well as cycle length, which implies that specific cycle length and LT interval exist to maximize capacity for given LT volume. The study is designed is designed to calculate utilization factors of LT lane for thru traffic and capacities, and identify signal timings to yield maximum capacity. The experimental design involved has 3 variables; 1)LT volumes at each approach(20-300 vph), 2)cycle lengths (60-220 sec), and 3)LT intervals(2.6-42 sec) for one scenario of isolated intersection crossing two 6-lanes streets. For LT volume of 50-150 vph, capacity calculated by using the utilization factor is about 25% higher than that by critical lane method. The range of optimum cycle length to yield maximum capapcity for LT volume less than 120 vph is 140-180 sec, and increases as LT volume increases. The optimum LT interval to yield maximum capacity is longer than the intrval necessary to accommodate LT volume at saturation flow rate.

• 대한교통학회지
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• 제14권2호
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• pp.45-58
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• 1996

In a large signal intersection, it is the most important to set phase sequences and phase intervals of traffic signal in order to improve the efficiency of the capacity as well as safety. These setting allows to select the best sequence of signal phase among several alternatives, and thus to rearrange the starting and ending points of the individual phase using an effective interphase periods (EIP). The EIP is a gap between previous and current traffic movements at a potential collision point in an intersection. Each of traffic movements has an equality for safety and efficiency at the balanced condition of EIP. This paper presents how to set optimally the phase sequences and intervals of traffic signal in an intersection using phase based approach. And in the second part, we applied the theory developed in the first part. In particular, a numerical example of phase base signal setting is presented using a matrix computation method in order to select the best sequence among several alternatives, and thus to rearrange the starting and ending points of the individual phase using the EIP. This method also allows to apply to optimum signal setting even in five-lag or staggered-type intersection.

• 전자공학회논문지B
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• 제30B권6호
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• pp.100-108
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• 1993

In this paper, noticing the point of human's ability which appropriately cope with vague conditions, we design fuzzy traffic signal light controller similar to human's distinction ability and decide the optimum cycle most suited to any traffic junction using fuzzy identification algorithm. In this study, for the control output decision process we design fuzzy controller better than electronic vehicle actuated controller in performance. We propose the cycle decision method which is not limited by the variance of traffic junction vehicle number through overcoming the limit of Webster's method which is adopted by the fixed cycle controller. Simulated experimental results show that fuzzy controller and fuzzy identification algorithm are better than the existing electronic vehicle actuated controller and fixed cycle controller in delay time per vehicle.

• 전기의세계
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• 제20권4호
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• pp.12-16
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• 1971

The electrical detector and computer systems for traffic flow and speed measurement are demonstrated in this paper. For the best traffic control optimization, linear and non-linear equations in the transition state are dealing with the perturbation of the linear car-following. In the conclusions, we construct a realizable system for the central automatic traffic control with a computer. Furthermore, fixed periodic switching system by manual with the automatic traffic control system is recommended for emergency perturbation.

• 대한공간정보학회지
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• 제5권2호
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• pp.131-144
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• 1997

날로 심각해져 가는 교통체증은 교통량에 비해 도로용량이 부족하여 나타나는 현상이나, 도로부족만이 교통체증의 주요 원인이라고 단정지을 수는 없다. 왜냐하면, 도시의 중추적 기능이 도심에 집중되어 있고 교통수요가 시간대별로 고르게 분포되어 있지 않기 때문이다. 이 연구는 개개의 운전자가 원하는 속도를 유지할 수 있는 통행의 질을 평가하는 주행계획에 있어서, 출발지로부터 목적지까지의 경로선택 시, 교통지체가 가장 적게 발생하는 선을 선택한다는 사실에 착안하여, 복잡한 가로망에 대하여 GIS기법을 이용한 경로를 교통량과 토로용량분석의 경로에 따라 가로별, 교차로별로 분석하여 기하급수적으로 증가하는 토로교통수요에 따라 시시각각 변모하는 토로, 교통, 운전자특성파악에 접근하고자 하며, 또한 가로별, 교차로별로 인접한 교통유발구역에 대한 분석과 같은 네트웍으로 시간당, 일주일의 하루 및 즉시 분류를 다양한 조건하에서 발생하는 교통지체경향에 대한 실제적 최적경로를 획득하고자 하며, 차후 최적경로 선택에 따른 교통의 원활한 배분을 통해 도로이용의 효율성 증대라는 결과를 기대하고, 따라서 교통량 대 도로용량과의 비에 따른 구간분석을 통하여 도로의 확장 및 확충의 적정시기를 결정하는데 있어서 과학적, 객관적이며 타당한 근거를 마련하고자 한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.121-124
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• 2000

In IMT-2000 systems, the outer loop dynamically adjusts the target SIR so that adequate performance in terms of the frame error rate(FER) and the true quality measure is achieved. This paper utilizes an analytic model lot outer loop power control(OLPC) adjusting the target SIR in IMT-2000. The analytic model is based on the discrete-time Markov chain as voice traffic SIR. It is described that the model can be used to find the optimum step size in voice traffic for fast fading environments. The optimum step size influences the performance of OLPC： As the step size decreases, the average target SIR increases and average FER decreases.