• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.244-250
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• 1994

This paper presents the design of a new turn-off gate drive circuit for GTO which can accomplish faster turn-off switching. The major disadvantage of the conventional turn-off gate drive technique is that it has a difficulty in realizing high negative diS1GQT/dt because of VS1RGM(maximum reverse gate voltage) and stray inductances of turn-off gate drive circuit[1~2]. The new trun-off gate drive technique can overcome this problem by adding another turn-off gate drive circuit to the conventional turn-off gate drive circuit. Simulation and experimental results of the new turn-off gate drive circuit in conjunction with chopper circuit verify a faster turn-off switching performance.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.3
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• pp.9-15
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• 2011

The left-turn actuated signal control method has been occurred various problems under the COSMOS. one of problems is a early termination for left-turn phase by u-turn vehicles at left-turn lane. Therefore, the purpose of this study is a development of the efficient left-turn actuated signal control method to improve the problem. This study was considered that setback the left-turn vehicle detector to the start point of u-turn line and adjustment of the passage time. For effective analysis of developed method, Traffic simulation was simulated by T-7F and VISSIM under various traffic conditions. The result was proved that the developed Method improved the effectiveness.

• Journal of Korean Port Research
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• v.11 no.1
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• pp.29-44
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• 1997

The purpose in this study was to review the travel characteristics of the left-turn signal system on the signalized intersections under the study in Pusan area, construct the appropriate transportation systems under the different left-turn signal system : Protected Left-Turn signal system, Permissive Left-Turn signal system, and Protected-Permissive Left-Turn signal system based upon the travel characteristics reviewed, and finally suggest the optimal left-turn signal system which could reduce traffic delay and fuel consumption. and also improve traffic safety on the signalized intersections based upon the optimal transportation system constructed. Based upon the results, it was concluded that the Protected-Permissive Left-Turn signal system would be better and safer than the Permissive Left-Turn signal system in the aspects which could reduce decrease delay and fuel consumption, and simultaneously increase traffic safety on the signalized intersections, even if the optimal Permissive Left Turn signal system was found to be the best left-turn signal system in the aspects of the Measures of Effectiveness(MOE) on the intersections under the study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.663-669
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• 2011

In this study, the optimal length of left-turn lane in permissive left-turn signal system at the signalized intersection which has a left-turn bay is estimated. It is a simulation analysis using the queueing theory that estimate the length of left-turn lane. Traffic density conform to the standards of operating a permissive left-turn system of the Practical Manual Traffic Safety Facilities. And each of a left-turn arrival rate, a left-turn service rate, left-turn average queueing time, for green time average queueing vehicle, for red time average queueing vehicle and average queueing vehicle cycle is calculated. As a result of this study, we would learn how much the space should be secured at the signalized intersection which has a left-turn bay. The methodology using the queueing theory to work out the optimal length of waiting lane in the permissive left-turn signal system was presented.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.36-47
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• 2006

The process of dual spin turn maneuver is introduced for attitude acquisition or recovery from flat spin state of a satellite. The physical principle of momentum transfer during dual spin turn is explained clearly. The case studies of special dual spin turn, in addition to the conventional dual spin turn, that are known as an acceptable cases, are performed to investigate the principle of dual spin turn and to provide a physical insight as well as the solution of dual spin turn. This study is done based on case-study simulation, which includes two-state control scheme composed of open-loop maneuver and energy dissipation device. Furthermore, we investigate the stability for the verification of all control cases after implementing two-stage control. We also provide the simulation scenario of flat spin recovery using dual spin turn method as an example.

• Journal of Korean Society of Transportation
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• v.32 no.6
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• pp.579-588
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• 2014

In this study, three signal control strategies such as Bike box, Hook-turn, and 6-phase were assessed for various traffic conditions at signalized intersections incorporating bicycle left-turn traffic. Results showed that the size of a waiting zone mainly affected the performance of signal control in both Bike box and Hook-turn. Both Bike box and Hook-turn yielded an identical vehicle delay, but Bike box produced less bicycle delay than Hook-turn by 2.5~29.9 sec/veh for undersaturated traffic conditions. For saturated traffic condition, Bike box produced less vehicle delay than Hook-turn and 6-phase strategies, but bicycle delay was found to increase at the 700 vph of bicycle traffic compared to 6-phase. Bicycle delay was greatly increased under Hook-turn and Bike box strategies when bicycle traffic was greater than 300 vph and 500 vph, respectively. It was also shown that bicycle delay could be significantly reduced by providing appropriate size of queueing space. In addition, Bike box was likely to yield less vehicle and bicycle delay than Hook-turn for traffic volume patterns investigated in this study.

• Journal of Korean Society of Transportation
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• v.35 no.1
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• pp.79-89
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• 2017

The purpose of this study is to analyze the current right-turn operation at signalized intersections and suggest appropriate right-turn operation strategy. From field investigation, right-turn signals have not only operated various type and shape, lacking of consistency, but also there was no clear regulations or standards. It could increase drivers' confusion and cause vehicle-to-pedestrian accidents. In order to improve pedestrian safety, there is urgent need to study the regulations and standards regarding to right-turn traffic control. This study suggests appropriate right-turn signal operation strategy. In case of permissive right-turn operation, it should be stated on regulations that red light means right-turn vehicles must stop temporarily at the stop line and then turn right. Necessary conditions for installing right-turn signal for protected operation are that there should have one or more exclusive right-turn lanes and right-turn signal face should contain the lenses with three-color arrow indication. In addition, we assort right-turn operation types as permissive, protected and protected/permissive right-turn and suggest specific signal operation strategy by the types.

• Journal of Korean Society of Transportation
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• v.18 no.1
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• pp.17-26
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• 2000

U-turns are allowed widely at the intersections by local police department while the left-turn Phases have been gradually Prohibited. However, any strategies for U-turn movements at signalized intersections are unavailable. Therefore, the Purpose of this study is to Propose the efficient operational method of Urban arterial adopting U-turn strategies. Four alternatives are evaluated they are, 1) U-turn movements are allowed at the adjacent intersection with exclusive U-turn lane while the major or the minor approach is Prohibited, 2) U-turn movements are allowed at the adjacent mid-block Pedestrian crossing with exclusive U-turn lane while the major approach is Prohibited. 3) U-turn movements are allowed at the adjacent mid-block Pedestrian crossing with exclusive U-turn lane while the minor approach is prohibited and 4) Comparative one between alternative 3 and 4. From the results of this study, it concludes that the method of U-turn movements allowed at the adjacent mid-block pedestrian crossing with exclusive U-turn lane is the most effective strategy among those alternatives. The strategies of alternative 1 and 4 are Proposed by the boundary based on the major through and left-turn volumes and the minor left-turn volume.

• Korean Journal of Applied Biomechanics
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• v.27 no.4
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• pp.257-262
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• 2017

Objective: This study aimed to investigate the differences in skiing time and vertical ground reaction force (vGRF) between the basic parallel turn and short turn. Method: Eleven alpine ski instructors (age: $28.73{\pm}4.29yrs$, height: $172.36{\pm}6.30cm$, body mass: $71.45{\pm}9.16kg$, career: $11.09{\pm}2.70yrs$) participated in this study. Each skier was asked to perform a basic parallel turn and short turn on a $16^{\circ}$ groomed slope. A foot pressure measurement system was used to measure the skiing time and vGRF under the three plantar regions (forefoot, midfoot, rearfoot). Results: Skiing time decreased significantly in all three phases during the short turn (p<.05). In the initiation phase, the vGRF showed a greater decrease on the midfoot and rearfoot during the short turn (p<.05). In the steering phase 1, the vGRF showed a greater increase on the forefoot and decreased on the midfoot during the short turn (p<.05). In the steering phase 2, the vGRF showed a greater increase on the forefoot and rearfoot during the short turn (p<.05). Conclusion: Our findings proved that the skiing time and vGRF changed during the short turn. Consequently, we suggest that recreational skiers should decrease the skiing time of the steering phase compared to that of the initiation phase and increase the vGRF on the forefoot and rearfoot in the steering phase.

• Journal of Arbitration Studies
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• v.14 no.1
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• pp.315-344
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• 2004

Although we try to increase the order of turn key construction for the international competitiveness strengthening, the construction quality advancement and the productivity enhancement of the public sectors, the problems of the domestic turn key systems are causing the hardships of all the participants and many possible disputes. The home turn key constructions have been activated since 1997. A lot of trial and error had been experienced in these days, and the turn key systems have been changed little by little. But the bases are continuously kept because of their reflecting all the participants' opinions. In the inner turn key constructions the problems of uniform types are repeatedly occurred, and, especially, many problems happen up to the stage of early stage owing to the specialties of the turn key construction. So the dispute factors of the Korean turn key constructions were abstracted through the literature searches, the site document examinations, the case studies and the interviews with the experts. When the technicians meeting the interior turn key construction for the first time and working here now are well acquainted with only these factors, many disputes will be prevented.