• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.8 no.1
• /
• pp.165-172
• /
• 1988

An optimal network design method using continuous form of design variables is considered. Modified Hooke-and-Jeeves algorithm has been implemented in order to solve nonlinear progamming problem which is approximately equivalent to the real network design problem (NDP) with system. efficiency criteria(i. e. travel time and costs) and construction cost as objective function. Various forms of construction cost function, locations of initial solution, and dimension of initial step size of link improvement are taken into account to show the validity of this approach. The results obtained are quite promising in terms of the numbers of evaluations in solving NDP, and the speed of convergence. Finally, some techniques in choosing efficient intial solution, initial step size and approximation are given.

• The Journal of Engineering Geology
• /
• v.14 no.2
• /
• pp.179-187
• /
• 2004

This study conducted a laboratory work to determine the change of dielectric constant of saturated soil porous media, which is injecting EML to use Frequency Domain Reflectometry(FDR) system and length 7cm-length measurement sensor. It is purpose of study that estimate a movement path through pore of soil for an ethanol mixing liquid(EML) which have the same specific gravity of water at $20{\;}^{\circ}C$, and determine to a dielectric measuring range for the measurement sensor. As an outflow point of saturated soil column upper part recedes from an EML inject point in EML diffusion test, the diffusion extent of EML through pore of saturated soil was expanded. And results of ail EML flow experiment were measured the change of dielectric constant at all measurement sensors which are placed to constant interval at the same travel time for saturated soil column. Therefore, the displace process of water that exist in pore of saturated soil by EML injection is enough available and confirm together mobility through pores.

• Journal of radiological science and technology
• /
• v.41 no.4
• /
• pp.339-344
• /
• 2018

Humans received an exposure dose of 2.4 mSv of natural radiation per year, of which the contribution of spacecraft accounts for about 75%. The crew of the aircraft has increased radiation exposure doses based on cosmic radiation safety management regulations There is no reference to air passengers. Therefore, in this study, we measured the radiation exposure dose received in the sky at high altitude during flight, and tried to compare the radiation exposure dose received by ordinary people during flight. We selected 20 sample specimens, including major tourist spots and the capital by continent with direct flights from Incheon International Airport. Using the CARI-6/6M model and the NAIRAS model, which are cosmic radiation prediction models provided at the National Radio Research Institute, we measured the cosmic radiation exposure dose by the selected flight and departure/arrival place. In the case of exposure dose, Beijing was the lowest at $2.87{\mu}Sv$ (NAIRAS) and $2.05{\mu}Sv$ (CARI - 6/6M), New York had the highest at $146.45{\mu}Sv$ (NAIRAS) and $79.42{\mu}Sv$ (CARI - 6/6M). We found that the route using Arctic routes at the same time and distance will receive more exposure dose than other paths. While the dose of cosmic radiation to be received during flight does not have a decisive influence on the human body, because of the greater risk of stochastic effects in the case of frequent flights and in children with high radiation sensitivity Institutional regulation should be prepared for this.

• Journal of Korean Society of Transportation
• /
• v.18 no.2
• /
• pp.17-26
• /
• 2000

LOS(Level of Service), the qualitative measure describing operational condition of highway, must be evaluated as quantative index in terms of user service. So, This study is focused on developing the user cost function that user cost is measured in the variation of V/C, MOE(Measure of Effectiveness) of LOS in basic Section of highway. The user cost is calculated as the sum of accident cost, operation cost, travel time cost. The data is collected in the four basic section of Singal-Ansan and Jung bu Highway. As the result of user cost function analysis, the user cost is the lowest When V/C is 0.54. Considering the V/C ratio(0.7) of Basic Section in rural highway suggested in KHCM, We find out that the LOS suggested KHCM increase the user cost of highway.

• Journal of Korean Society of Transportation
• /
• v.17 no.2
• /
• pp.91-103
• /
• 1999

이 연구는 자동 차량위치 측정기법(Automatic Vehicle Location, AVL)을 이용해서 수집한 교통상황자료를 가지고 구간 통행시간을 산출하는 알고리즘을 개발한다. AVL기법을 이용하는 경우, 처리해야 할 자료량이 많아서 실시간에 정보를 산출하는 것이 힘들다. 따라서 이 연구는 처리해야 할 자료량을 가능한 한 줄이고 자료량이 적은 경우에도 효율적인 구간통행시간을 산출하는 알고리즘을 제시한다. 이 연구의 방법론은 크게 4가지인데, 첫째, 해석 기법, 둘째, 회귀분석, 셋째, 인공지능 및 전문가 시스템, 넷째, 통계분석이다. 이 방법론을 이용해서 세 단계 알고리즘을 개발하는데, 첫째는 실시간 분석통계 알고리즘, 둘째는 과거자료분석 알고리즘, 셋째는 자료응합 알고리즘이다. 이 알고리즘 가운데 자료융합 알고리즘 결과가 산출하고자 하는 구간 통행시간이다. 실시간 분석통계 알고리즘은 연속하는 세 개 구간의 통행 패턴을 이용해서 가운데 구간의 통행시간을 산출하는 방법을 제시한다. 또 실시간 분석통계 알고리즘으로 산출하지 못한 구간은 인접구간 상관도 정보를 이용해서 구간통행시간을 추정한다. 과거자료분석 알고리즘은 회귀분석을 이용해서 시간대별 통행시간 평균과 분산을 구하고, 이 결과를 바탕으로 인접구간 상관도 정보를 오프라인으로 구하는 알고리즘이다. 자료융합 알고리즘은 2가지 단계를 거치는데, 그것은 실시간 자료융합과 최종 자료융합이다. 실시간 자료융합은 실시간에 가까운 자료원의 실시간 분석통계 알고리즘 결과 패턴과 인접구간 상관도 정보를 이용한 구간통행시간 추정 결과를 이용해서 패턴에 따라 다른 방법으로 융합을 하는 알고리즘을 개발한다. 최종 자료융합은 실시간 자료융합 결과와 회귀분석 결과의 패턴을 이용해서 구간 통행시간을 산출한다. 이 연구를 기존 연구와 비교할 때, 세 가지 독차성이 있다. 첫째는 연속하는 세 구간 통행 패턴을 분석하였기 때문에 기존의 노드의존 방식을 탈피하였다는 점이다. 따라서 자료량이 적은 경우도 믿을만한 통행시간을 산출할 수 있다는 것이다. 둘째는 인접구간 상관도 정보를 구간통행시간 산출에 이용하였기 때문에 자료를 효율적으로 이용할 수 있다는 점이다. 셋째는 자료원 패턴을 분류하고 전문가 시스템을 이용하여 자료융합 하였기 때문에 수행속도가 빠르고, 신뢰성있는 정보를 제공한다는 점이다. 이 연구는 개발한 알고리즘 정확도를 검증하기 위해서 두 가지 검증방법을 이용하였다. 첫째는 시뮬레이션을 이용한 것이고, 둘째는 실제 주행조사 분석을 이용한 것이다. 두 가지 검증 결과는 알고리즘 정확도를 보여준다.

• Journal of Korean Society of Transportation
• /
• v.24 no.3 s.89
• /
• pp.197-205
• /
• 2006

The study suggested a demand forecasting method which explicitly reflects transfer between various transport modes especially related light rail transit project with multi-modal transit system. The suggested method classifies several groups depending on characteristic of trips and applies different demand model for each group to explain travel pattern more realistically More specifically. the trips was classified by trips within the LRT route, trips between inside and outside of the LRT route. and through trips via the LRT route. The study also suggested a evaluation measurement of time saving due to the LRT construction, which are consistent along with the do-case and the do-nothing-case even though some mode shift could be happen after introducing the LRT.

• Journal of Korean Society of Transportation
• /
• v.25 no.6
• /
• pp.171-183
• /
• 2007

Urban transport demand is derived from activity participation. A variety of individual daily activities based on the decisions on activity participation result in collective spatial behavior. The travel derived from the effort to overcome the spatially distributed locations of adjacent activities represents the detailed structural relationships among activities. An activity-based approach provides an important framework of analyzing contemporary urban daily life in the sense that it studies the interaction between individuals' daily decision making and social practice in time and space, on the one hand, and socio-spatial environment on the other. The current study identifies representative patterns of urban daily activity implementations and analyzes the correlation between representative patterns and individuals' characteristics and contextual characteristics. The study shows that urban daily activity patterns can be grouped in a limited number of representative patterns, which are systematically correlated with socio-spatial characteristics. The results provide related transportation policy implications.

• Journal of Korean Society of Transportation
• /
• v.34 no.6
• /
• pp.570-579
• /
• 2016

This study proposes a concept of Stepwise Transfer Coefficient(STC) which implies greater transfer cost with increasing the number of transfers. Thus, the public transport information system provides the choice sets of travel routes by the consideration of not only transportation time but also the optimum number of transfers. However, path choice problems that involve STC are found to include non additive cost, which requires additional route enumeration works. Discussions on route enumeration in actual transportation networks is very complicated, thereby warranting a theoretical examination of route search considering STC. From these points of view, this study results in a probability based transit trip assignment model including STC. This research also uses incoming link based entire route deletion method. The entire route deletion method proposed herein simplifies construction of an aggregation of possible routes by theoretically supporting the process of enumeration of the different routes from origin to destination. Conclusively, the STC reflected route based logit model is proposed as a public transportation transit trip assignment model.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1145-1149
• /
• 2006

The typhoon Rusa passed through the Korean peninsula from the west-southern part to the east-northern part in the summer season of 2002. The flash flood due to the Rusa was occurred over the Korean peninsula and especially the damage was concentrated in Kangnung, Yangyang, Kosung, and Jeongsun areas of Kangwon-Do. Since the latter half of the 1990s the flash flood has became one of the frequently occurred natural disasters in Korea. Flash floods are a significant threat to lives and properties. The government has prepared against the flood disaster with the structural and nonstructural measures such as dams, levees, and flood forecasting systems. However, since the flood forecasting system requires the rainfall observations as the input data of a rainfall-runoff model, it is not a realistic system for the flash flood which is occurred in the small basins with the short travel time of flood flow. Therefore, the flash flood forecasting system should be constructed for providing the realistic alternative plan for the flash flood. To do so, firstly, Flash Flood Monitoring and Prediction (FFMP) Model must be developed suitable to Korea terrain. In this paper, We develop the FFMP model which is based on GIS, Radar techniques and hydro-geomorphologic approaches. We call it the F2MAP model. F2MAP model has three main components (1) radar rainfall estimation module for the Quantitative Precipitation Forecasts (QPF), (2) GIS Module for the Digital terrain analysis, called TOPAZ(Topographic PArametiZation), (3) hydrological module for the estimation of threshold runoff and Flash Flood Guidance(FFG). For the performance test of the model developed in this paper, F2MAP model applied to the Kangwon-Do, Korea, where had a severe damage by the Typhoon Rusa in August, 2002. The result shown that F2MAP model is suitable for the monitoring and the prediction of flash flood.

• Korean Journal of Organic Agriculture
• /
• v.11 no.3
• /
• pp.1-19
• /
• 2003

The operation of a five day workweek seems to be increased continuously, Many city-workers will make good use of their spare time and search after a lot of devices that can seek for the maximum value of leisure utility. The demand of potential customers that want to enjoy weekend in farming villages is coming out greatly. That is, the condition of users that will travel the farming villages is getting better. But the actual states of farming villages are not ready in many parts yet. Therefore we must activate the tourist attraction in farming villages that can be satisfied the city-workers' expectation. And after making the sightseeing environment infrastructure, we must develop the programs intimate with environment, improve the sightseeing agricultural management and consolidate various systems as soon as possible. So in this study, after investigating the demand preference degree of city-workers, I tried to grope an activation plan with the base which will reach. Being more urgent what more, not the simple sightseeing agriculture that the farming experience was the focus of, but it is very important to develop the program of environment sightseeing agriculture. It will lay the stress on playing and education culture which city-workers can enjoy and experience. And with constructing the base facility like a city form, we must develop cheap and various goods and the execution of modernized weekend farms. For this, first the consciousness conversion against the customer management of farmers must precede and the change of government policy and the support polity is important. I hope that this study with the five-day workweek has the chance to contribute in the economic growth of farming villages and efficient use and management of the natural environment resources through the activation of sightseeing agriculture.