• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.79-85
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• 1998

The 9-digit MMSI(Maritime Mobile Service Identity) in the NBDP is converted to the 7-digit identity signal, used to identify to the phase of and to synchronize to the clock of the ISS(Information Sending Station) automatically for phasing procedure between radio stations. In this paper, algorithms for the automatic identification phasing procedures and for conversions, calculations between 7-signals and 9-identity, those check-numbers in the phasing procedures for calling of the NBDP are discussed and designed. And a method of the faster locking and phasing for calling than that of recommended by ITU-R is suggested and implemented.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.3
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• pp.19-26
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• 1983

Through traffic utilization of left turn lane constitutes an unique traffic operation at an intersection. Consequently, due to the provision as of current practice, conventional methods which estimate traffic volume and intersection capacity by lane would not be valid for design of signal timings. Through traffic utilization factor of left turn lane is affected by left turn volume and signal timings. The primary purpose of this study is to compare the results from leading left turn green phasing scheme with those from previously studied lagging left turn green phasing scheme in terms of utilization factor and intersection capacity by various left turn volume and signal timings, and thereby optimum signal timing to maximize the capacity at given left turn volume. Leading left turn green phasing increases capacity by 10~15 % as compared with that for current lagging left turn green phasing scheme. The range of optimum cycle length for left turn volume about 150 vph is 180~200 second. This cycle length range and left turn interval are longer than those for the lagging left turn green phasing scheme.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3614-3619
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• 2022

To operate the ion cyclotron resonance heating (ICRH) antennas in a better heating state and produce relatively low impurities, it is necessary to control the antenna spectrum by changing the antenna phasing. As the electrical length of the antenna feeding transmission lines is changing as a matter of the standing wave pattern at the ceramic supports, 90° elbows, T-connectors and antenna loops, we chose to measure the current at the grounding points of the antenna loops by antenna strap probe. The voltage drops along a small, several millimeter-long paths at the end of the antenna loops give a signal that is proportional to the current in the antenna loop. Through the simulation of the antenna strap probe and the actual measurement of the antenna phasing under vacuum conditions, the reliability of the antenna strap probe based diagnostic system have been successfully proved. Moreover, this system was successfully applied to the ICRH daily experiments in the spring of 2021. In the near future, the active real-time feedback control of the antenna phasing system will be developed based on this diagnostic system in the EAST tokamak.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.149-159
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• 2002

The performance of two single-barrier three-phase control systems at diamond interchanges was evaluated for various traffic conditions. To emulate the actuated signal control, hardware-in-the-loop system combined with CORSIM simulation program was used. Two performance measures, average delay and total stops, were used for the evaluation process. Results showed that the two three-phase systems gave similar performance in terms of average delay, but not stops. The delay performance of each phasing system was generally dependent on the traffic pattern and ramp spacing. However, there was a distinct movement preference for each phasing system. The total stops decreased as the spacing increased, and it was the most sensitive variable that can differentiate between the two three-phase systems. It was also shown that the hardware-in-the-loop control could be a good method to overcome the limitations of current simulation technology.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.472-478
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• 2017

In this paper, we deals with optimizing traffic signal timing in grid networks by using a network topology design method. Optimizing traffic signal timing includes minimizing delay time delay between departure and destination by interlocking straight traffic signal in the minimum spanning tree(MST). On the assumption that users of network abide by the paths provided in this paper, this paper shows optimizing traffic signal timing in grid networks. the paths provided in this paper is gathered by using Dijkstra algorithm used in computer networks. The results indicate minimizing delay time of passing through the grid network and interlocking traffic signal in the grid network.

• Journal of Korean Society of Transportation
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• v.1 no.1
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• pp.10-27
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• 1983

In order to improve the traffic enviroments in the urban streets of Seoul, the computer controlled traffic signal system was installed on 45 intersections at 1980. Afterward, yearly expansion was done to the numbers of 132 intersections and 232 loop detectors. The problems of timing plans were discussed, mainly pedestrian crossing timing as well as the generations of split and offset. The broad urban streets more than 30m require long phasing time of pedestrians, even though the equivalent or correspondent traffic volume is rare. The configuration of computer system for traffic control was disscussed in terms of control strategy. An overview also given. The improvements were measured at every quater. The travel speed improved to 42%, delay time reduced to 41% and number of stops to 43% respectively.

• Proceedings of the KOR-KST Conference
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• 2002.02a
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• pp.143-159
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• 2002

The performance of two single-barrier three-phase actuated control systems at diamond interchanges was evaluated for various traffic conditions. To emulate the actuated signal control, hardware-in-the-loop system combined with CORSIM simulation program was used. Two performance measures, average delay and total stops, were used for the evaluation process. Results showed that the two three-phase systems gave similar performance in terms of average delay, but not stops. The delay performance of each phasing system was generally dependent on the traffic pattern and ramp spacing. The total stops decreased as the spacing increased, and it was the most sensitive variable that can differentiate between the two three-phase systems. It was also shown that the hardware-in-the-loop control could provide a good method to overcome the limitations of current simulation technology.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.127-135
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• 1999

Most existing progression bandwidth models maximize the single or multi weighted sum of bandwidths in the both directions to improve traffic mobility on an arterial, but they cannot be applied to general networks. Even though a few models formulating a looped network problem cannot be applied to networks have not loops. Also they have some defects in optimizing phase sequences. Therefore, the objective of this study is to develope a mathematical formulation of the synchronization problem for a general traffic network. The goal is achieved successfully by introducing the signal phasing for each movement and expanding the mixed integer linear programming of MAXBAND. The experiments indicate that the proposed model can formulate the general traffic network problem mere efficiently than any other model. In conclusion, this model may optimize signal time to smooth progression in the general networks.

• Proceedings of the KOR-KST Conference
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• 1995.02a
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• pp.3-32
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• 1995

The Highway Capacity Manual specifies procedures for evaluating intersection performance in terms of delay per vehicle. What is lacking in the current methodology is a comparable quantitative procedure for ass~ssing the safety-based level of service provided to motorists. The objective of the research described herein was to develop a computational procedure for evaluating the safety-based level of service of signalized intersections based on the relative hazard of alternative intersection designs and signal timing plans. Conflict opportunity models were developed for those crossing, diverging, and stopping maneuvers which are associated with left-turn and rear-end accidents. Safety¬based level-of-service criteria were then developed based on the distribution of conflict opportunities computed from the developed models. A case study evaluation of the level of service analysis methodology revealed that the developed safety-based criteria were not as sensitive to changes in prevailing traffic, roadway, and signal timing conditions as the traditional delay-based measure. However, the methodology did permit a quantitative assessment of the trade-off between delay reduction and safety improvement. The Highway Capacity Manual (HCM) specifies procedures for evaluating intersection performance in terms of a wide variety of prevailing conditions such as traffic composition, intersection geometry, traffic volumes, and signal timing (1). At the present time, however, performance is only measured in terms of delay per vehicle. This is a parameter which is widely accepted as a meaningful and useful indicator of the efficiency with which an intersection is serving traffic needs. What is lacking in the current methodology is a comparable quantitative procedure for assessing the safety-based level of service provided to motorists. For example, it is well¬known that the change from permissive to protected left-turn phasing can reduce left-turn accident frequency. However, the HCM only permits a quantitative assessment of the impact of this alternative phasing arrangement on vehicle delay. It is left to the engineer or planner to subjectively judge the level of safety benefits, and to evaluate the trade-off between the efficiency and safety consequences of the alternative phasing plans. Numerous examples of other geometric design and signal timing improvements could also be given. At present, the principal methods available to the practitioner for evaluating the relative safety at signalized intersections are: a) the application of engineering judgement, b) accident analyses, and c) traffic conflicts analysis. Reliance on engineering judgement has obvious limitations, especially when placed in the context of the elaborate HCM procedures for calculating delay. Accident analyses generally require some type of before-after comparison, either for the case study intersection or for a large set of similar intersections. In e.ither situation, there are problems associated with compensating for regression-to-the-mean phenomena (2), as well as obtaining an adequate sample size. Research has also pointed to potential bias caused by the way in which exposure to accidents is measured (3, 4). Because of the problems associated with traditional accident analyses, some have promoted the use of tqe traffic conflicts technique (5). However, this procedure also has shortcomings in that it.requires extensive field data collection and trained observers to identify the different types of conflicts occurring in the field. The objective of the research described herein was to develop a computational procedure for evaluating the safety-based level of service of signalized intersections that would be compatible and consistent with that presently found in the HCM for evaluating efficiency-based level of service as measured by delay per vehicle (6). The intent was not to develop a new set of accident prediction models, but to design a methodology to quantitatively predict the relative hazard of alternative intersection designs and signal timing plans.

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.19-33
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• 2004

신호교차로 운영 최적화를 위한 4가지 변수인 주기, 현시순서, 현시녹색시간, 옵셋 중에서 지금 지 정형화된 지침이 없이 전문가의 경험이나 휴리스틱한 규칙(Heuristic rule)에 의해 결정되었던 현시순서에 대해 다양한 교통조건을 고려하여 최적현시와 지체변화를 분석하였다. 교통조건은 독립/연동교차로, 교차로 기하구조, 비혼잡/혼잡상태, 통과교통량에 대한 좌회전 교통량비(LT/Thru)에 따라 Dual ring에서 구현가능한 모든 현시순서를 대상으로 최적현시를 도출하였다. 분석과정에서 비혼잡상태의 경우 LT/Thru가 작을수록 직진 중첩 동시신호가 가장 우수하게 나왔으며, LT/Thru가 크게 증가할수록 선행양방향좌회전이 양호하게 나타났다. 혼잡상태의 경우는 LT/Thru 15%에서 공통적으로 최적현시가 변하였는데 이는 포화도와 이동류별 녹색시간비율이 크게 변하면서 급작스런 주기 증가에 기인한 것으로 판단되었다. 또한 독립교차로 및 연동교차로 현시순서 분석 결과를 보면 전반적으로 선행양방좌회전 현시와 직진 중첩 동시신호 현시가 가장 양호한 것으로 나타났으며, 양방 동시신호 현시는 대체로 지체가 높게 나타나 신호운영에 비효율적인 것을 다시 한번 입증하게 되었다. 특히 연동교차로에서는 연동에 중요한 요소인 옵셋과 진행대폭(bandwidth)의 상호관계를 탄력적으로 대응할 수 있는 직진 중첩 동시신호가 최적현시로 나타났다. 본 연구는 검지기가 설치되지 않은 고정식 신호기로 운영되는 지방부 및 도시 가로망의 교통류 효율성을 높이는 중요한 자료로 사용될 것으로 판단된다. 최근에는 실시간 교통신호 제어시스템이 활발히 연구. 운영되고 있는데 이 시스템 내에 포함되어 있는 TOD방식의 고정시간 제어(pretimed control)나 패턴선택제어(pattern selection control)에도 충분히 활용할 수 있을 것으로 사료된다.