• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.119-121
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• 2022

In this paper, we will make a model that finds optimal phase for each crossroad. When the traffic volume, traffic capacity, and the lane width of every direction is given for each crossroad, we aim to find the most efficient phase. We established an evaluation function that evaluates the efficiency of each phase using the values of the average waiting time in one direction, the average delay time, the standard deviation of the delay time, and the average delay time in each direction. The time allocation to optimize a phase pattern can be obtained by using the gradient decent method. Through this research, we hope to decrease the waiting time in transporation, thus improving the overall traffic condition in cities.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.202-207
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• 2000

The purpose of study was to compare the caries experience between the mentally retarded(MR) and the normal(N) children and adolescents and to survey the dental visit frequency. preventive dental care, and tooth-brushing behavior of the mentally retarded. Two hundred and fifty MR and two hundred and ten N subjects were selected for the study. 1. The number of teeth which had experienced caries was 3.28 in MR and 4.66 in N. The number of decayed teeth was 2.24 in MR and 1.50 in N. The number of filled teeth was 0.71 in MR and 3.06 in N Filled teeth rate was 19.78% in MR and 58.89% in N The differences between MR and N were all significant(P<0.01). 2. Dental visit frequency of MR was 1.15 per year, and the 51.2% of MR did not visit the dental clinic for the last one year. 38.0% of MR had received the preventive dental care. 3. Toothbrushing frequency per day was 2.16 and the toothbrushing time for 78.3% of MR was less than two minutes. 51.2% of MR brushed their teeth by themselves, 13.3% did with the help of the carers, and 35.5% totally depended on the carers. In conclusion, MR experienced less dental caries than N, had more untreated caries than N, and had need for regular preventive dental care.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.6
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• pp.90-101
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• 2016

This study was initiated to develop an algorithm for traffic condition adaptive optimal traffic signal control for isolated intersections based on the vehicle trajectory data. The algorithm determines the optimal cycle length, phase lengths, phase sequences using the data collected under V2X communication environment every second. In addition, the algorithm utilizes a traditional feature of the actuated signal control, gap-out, using traditional detector systems to consider the mixture of normal vehicles and vehicles equipped with the V2X communication function. The performance of the algorithm was compared with that of the fixed signal timing plan which was optimized with Synchro under a microscopic traffic simulation-based test bed. As a result, the overall performance, including average delay, average stop delay, the number of stops, and average speed, are improved apparently. In addition, the amount of improvement get bigger as the traffic volume in the intersection as well as the number of vehicles equipped with the V2X communication function increase.

• Journal of dental hygiene science
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• v.4 no.1
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• pp.39-44
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• 2004

The primary purpose of this report is to investigate the index of dental caries experiences and the state of oral hygiene for the children with mental retardation, cerebral palsy, and autism. In order to get those things we investigated 99 students that ages from 8 to 13 in three special schools (which are the school for the children with mental retardation, physical difficulties, emotional disturbance). Then collected the statistics and examined if there were some regardful differences among each type. (1) The investigation shows that there is no regardful differences among them in statistice. However, the averages of their dental caries experience have a little gap. The average of the children with mental retardation group is the highest and the autistic children group is the lowest, as we can see the facts of 4.70 for group of children with mental retardation, 4.58 for group of children with cerebral palsy, 3.67 for group of autistic children, children with mental retardation group is severe, autistic children group is few. (2) The conclusion from research of oral hygiene among each type, statistically regardful differences were revealed (p<0.05). It shows children with cerebral palsy is on worst state, children with mental retardation is on next state, autistic children is on best state by compare for averages among each type, 32.30 for group of children with mental retardation 35.00 for group of children with cerebral palsy, 27.79 for autistic children.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.7-16
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• 2009

Korea Highway Capacity Manual (2001) proposes only LOS(Level of Service) analysis method on non-control and two-way-stop intersections, not dealing with the analysis method on LOS for roundabouts, nor even including the term 'roundabout'. This study selects proper MOEs for roundabouts and criteria the LOS through simulation analysis. To attain this goal, the authors reviewed the methods to select proper MOEs in the first step, criteria the Los. For this study, the MOEs were chosen from existing literature, and used for the criteria. The MOEs to be applied to roundabouts in this research were entry traffic volume, v/c (volume/capacity) ratio, and average vehicle delays. The results showed that the maximum entry traffic volume(LOS F) at local one-lane roundabout was analyzed to be 1,700pcph and average vehicle delay 18 seconds LOS A was analyzed as 700pcph and average vehicle delay 3 seconds and v/c 0.41 in this case Maximum entry traffic volume(LOS F) at local area 2 lane roundabouts was analyzed as 2,900pcph and their average vehicle delay as 31 seconds LOS A was analyzed to be 1.500pcph and average vehicle delay 8 seconds, v/c 0.52.

• Journal of Korean Society of Transportation
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• v.15 no.3
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• pp.93-109
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• 1997

현재 사용되고 있는 신호등 설치기준은 교차로의 형태를 반영하고 있지 않다. 본 논문은 신호 및 비신호 T형 교차로에 대한 현장의 지체도 조사를 바탕으로 첨두시간 교통량을 이용한 T형 교차로의 신호등 설치기준을 개발하였다. 기준설정을 위해 교차로의 평균정지지체 최소화를 평가척도로 사용하였으며 주요 연구결과를 요약하면 다음과 같다. 첫째, T형 교차로의 지체도 모형은 주도로 교통량과 부도로 교통량을 독립변수로 하는 지수함수 형태를 갖는다. 둘째, T형 교차로의 신호등 설치기준은 T형으로 인한 현시의 감소로 MUTCD에서 제시하고 있는 신호등 설치기준과 비교시 타당성 교통량이 높게 나타났다. 셋째, T형 교차로의 신호등 설치를 위한 첨두시 교통량기준 도표를 작성하였으며, 평일의 하루중 주도로(양방향)의 시간당 교통량과 이에 사용하는 부도로의 시간당 교통량의 최대값을 도표에 표시했을 때 접근로 차로수의 조합에 해당하는 기준선의 상위영역에 위치하면 신호등을 설치하는 것이 교차로의 지체도를 최소화시킬수 있다.

• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.123-134
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• 2002

감응식 신호운영변수 설계에 관한 연구는 정주기식 신호운영변수 설계의 그것보다 그 수준이 현저히 미비하며 이는 감응식 신호운영 특성을 반영한 평가방법의 부재로 감응식 운영변수의 평가가 불가능하였기 때문이다. 본 논문은 최근에 소개된 평균 감응현시 녹색시간 추정 수리모형을 이용하여 Highway Capacity Manual (HCM) 지체도를 최소화하는 최대녹색시간의 설계방안을 제시한다. - '최소녹색시간'과 '단위연장시간'은 보행자 횡단시간 및 차량 차두시간 등 지역별 운전자/보행자의 특성과 관련이 있어 일반적인 최적화 설계 수리모형의 적용에 무리가 있어 제외한다. 제안된 설계방안은 감응식 운영논리를 토대로 감응현시 군의 평균녹색시간과 평균주기를 산정하며, HCM 지체도를 평가하고, 가능한 대안 중 지체를 최소화하는 최대녹색시간 운영변수 군을 '혼혈 유전자 알고리즘'으로 도출한다. 현장실험을 통해 도출이 불가능한 실제 최적치를 Corridor Simulation(CORSIM)모형을 이용하여 추정하였고 이를 제안된 설계방안으로 도출된 최대녹색시간 운영변수' 값들과 비교하였다. 비교결과 교차로 v/c 비율이 1.0 보다 낮을 시는 제안된 방법을 통해 설계된 최대녹색시간 운영변수 군이 최소 CORSIM 지체도를 산출하는 최대녹색시간 운영변수 군과 동일한 것으로, v/c비율이 1.0보다 높을 시는 다른 것으로 결과되었다. v/c비율이 1.0 보다 높은 경우는 정주기식 교차로 운영에 효율적이라 감응식 운영의 필요를 벗어나므로 제안된 최대녹색시간 설계방안은 감응식 신호운영 필요범위 내에서 효율적이다. 기존의 최대녹색시간 설계는 정수기식 최적녹색시간을 기준으로 최대녹색시간을 추정하며, 그러한 과정을 돕기 위하여 추정범위(설계자가 범위 내에서 임의로 선택함)를 제시하는 것이 기존의 연구임을 비교하면 본 연구에서 제안하고 있는 설계방법의 의미가 크다.

• Journal of Korean Society of Transportation
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• v.35 no.5
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• pp.385-395
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• 2017

This study deals with the small-scale roundabout. The purpose of this study is to analyze the average delay of vehicle in roundabout, and suggest the efficient planning and design standard. In pursuing the above, this study gives particular attentions to analyzing the average delay time according to the inscribed circle diameter, speed of circulatory roadway lane and traffic volume. The operational efficiencies of 96 scenarios (3 sizes of inscribed circle diameter ${\times}$ 4 types of circulatory roadway speed ${\times}$ traffic volume) are analyzed using VISSIM (Verkehr In $St{\ddot{a}}dten$-SIMulationsmodell). The main results are as follows. First, the optimal design speed of small-scale roundabout are derived from the above scenario analysis. Second, the traffic volume of LOS D is estimated to be 2,180-2,740pcph. Third, the traffic volume of LOS F that is required to improve is above 2.780pcph. The results might be expected to give some implications to providing the countermeasures for the operational efficiency of roundabout.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.1
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• pp.59-67
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• 2020

In this study, a suitable algorithm for each BRT stop type is presented through the network construction and algorithm design effect analysis through the LISA, a traffic signal program, for the BRT stop type in the BRT Design Guidelines, Ministry of Land, Transport and Maritime Affairs, 2010.6. It was. The phase insert technique is the most effective method for the stop before passing the intersection, the early green technique for the stop after the intersection, and the extend green technique for the mid-block type stop. The extension green technique is used only because it consists of BRT vehicles, general vehicles and pedestrians. Analyzed. After passing through the intersection, the stop was analyzed as 56.4 seconds for the total crossing time and 29.8 seconds for the delay time. In the mid-block type stop, the total travel time of the intersection was 40.5 seconds, the delay time was 9.6 seconds, the average travel time of up and down BRT was 70.2 seconds, the delay time was 14.0 seconds, and the number of passages was 29.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.4
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• pp.40-51
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• 2015

This study analysis traffic phase order alternatives to maximize throughput. According to theoretical analysis alternative2(EW: left turn after through, NS: through after left turn) and alternative5(EW: through after left turn, NS: left turn after through) can minimize the maximum delay. Both alternatives split the phase that have the same destination link under the whole cycle length. This shows that phase order alternative can effect to the fully saturated intersection. In side of simulation analysis by microscopic traffic simulator PTV VISSIM F 7.0, each phase order alternatives can't effect throughput under the non saturated condition. However under the saturated condition, the average controlled delay of the intersection has been changed by phase order alternatives. The simulation analysis shows that alternative2 and alternative5 increase throughput 3.8% to 5.1% under the saturated condition.