• 한국환경과학회지
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• 제3권4호
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• pp.393-402
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• 1994

It is necessary to examine the source contributions and the relationship between a receptor and sources for the resonable controlling of air pollution level of suspended particulate matters. Therefore, in this study, profiles of sources contributing to the concentration of suspended particulate matters, were developed and CMB model was applied to obtain information of source contributions and feasibility of CMB model application. According to the propose of this study, twenty-seven chemical species such as the elements, anions, and total carbon of thirty-six PMl0 and TSP data sets sampled at the Pomch'on receptor site in Pusan for a 24-hr period from May to Aug. 1992, were analyzed and three (transportation, soil, marine) different source profiles were developed through the field measurement. Applying CMB model to transportation, soil, marine, the results of source contribution by CMB model showed that the case with TSP was more suitable for CMB model than that with PMl0. And the average contribution of transportation source to TSP and PMlo concentration at Pomch'on receptor was calculated as 90.66 ㎍/m3(64%) and 23.27 ㎍/m3(39%), resfiectively, which showed that the contribution by transportation was dominant. The validation of CMB model was performed by means of the results of contributions from marine source for the wind direction sectors.

• 디지털산업정보학회논문지
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• 제8권4호
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• pp.193-203
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• 2012

This study analyzed regular transportation costs between port warehouses and processing plants and between processing plants and central distribution centers and further transportation costs relations according to empty transfer rates in each circulation by examining the distribution routes of imported grain including wheat, barley, corn, and soybean, namely port warehouses, processing plants, and central distribution centers. Based on the results, the study compared and reviewed the logistics transportation costs. The analysis results of the alternative model show that logistics operational costs could be considerably cut down by introducing a flexible vehicle transportation operational method, which is to change the vehicle loading parts for proper substitute transportation after unloading and transport them to other locations such as central distribution centers instead of returning empty, as an alternative to high operational costs deriving from empty vehicle operation in each circulation after unloading items in case of transportation of imported grain and processed items. The results allow for a more realistic approach to general problems with large-scale distribution network operation and provide a theoretical foundation to serve as a guide to establish policies for corporate operation of imported grain logistics systems.

• 방사성폐기물학회지
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• 제20권4호
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• pp.411-428
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• 2022

Given the domestic situation, all nuclear power plants are located at the seaside, where interim storage sites are also likely to be located and maritime transportation is considered inevitable. Currently, Korea does not have an independently developed maritime transportation risk assessment code, and no research has been conducted to evaluate the release rate of radioactive waste from a submerged transportation cask in the sea. Therefore, secure technology is necessary to assess the impact of immersion accidents and establish a regulatory framework to assess, mitigate, and prevent maritime transportation accidents causing serious radiological consequences. The flow rate through a gap in a containment boundary should be calculated to determine the accurate release rate of radionuclides. The fluid flow through the micro-scale gap can be evaluated by combining the flow inside and outside the transportation cask. In this study, detailed computational fluid dynamic and simplified models are constructed to evaluate the internal flow in a transportation cask and to capture the flow and heat transfer around the transportation cask in the sea, respectively. In the future, fluid flow through the gap will be evaluated by coupling the models developed in this study.

• Asia pacific journal of information systems
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• 제27권1호
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• pp.1-17
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• 2017

The need for effective information systems that can help in efficient transportation management has become essential. This study presents the potential benefits of developing a decision support system used by a trucking company for routing and scheduling. Our study investigates how customer exibility factors affect the utilization of transportation resources and establishes a vehicle scheduling model for better allocation of transportation resources with a time window. The results show vehicle savings from 25% up to 70% per day given different levels of exibility in delivery times. Increased capacity utilization can be achieved by considering only customer exibility in the model. Our study implies that incorporating customer exibility into the information system can help transportation organizations have the capability to gain control over management to cut costs and improve service.

• 대한교통학회지
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• 제13권4호
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• pp.47-59
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• 1995

The main purpose of this study is identifying the factors which affect the mode choice behavior of work trips. Disaggregate behavioral approach is used for the analysis . The data were collected using the questionnaire survey method in Taegu. Two models were developed in this study which are multinomial logit model(MODEL-1) for auto, taxi and bus and multinomial logit model (MODEL-2) for auto, taxi, bus and subway. The stated preference (SP) data were used for the analysis of the subway mode choice behavior. MODEL-1 provide reasonable results for the future application. A multinomial model (MODEL-2) developed using the stated preference(SP) data was tested for the use of future transportation mode. It is four that the those models provides reasonable results in terms of behavioral and statistical consideration.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 Asia Navigation Conference
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• pp.96-101
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• 2004

Core competence of enterprises became the focus of many researches recently. This essay summarizes the situation of Chinese harbor enterprises and establishes an evaluating model which makes use of factor-analysis.

• 대한교통학회지
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• 제32권4호
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• pp.357-368
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• 2014

지금까지 토지이용-교통모형은 전적으로 수치해석적 분석도구로만 이용되어 왔는데, 최근 이론개발 노력의 결과 정책변수에 대한 후생함수의 1계 도함수 간편식을 구할 수 있게 되었다. 본 논문은 혼잡통행료가 소득세 경감을 통해 재순환될 때 혼잡통행료의 변화에 대한 후생함수의 도함수를 어떻게 유도할 수 있는지 보여준다. 분석결과 혼잡통행료의 부과가 가져오는 후생변화분을 (1)혼잡의 완화로 인한 후생증가분과 (2)노동공급과의 상호작용에서 발생하는 후생손실로 분해할 수 있다. 이 결과는 기존의 연구결과와 일치한다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.152.1-152.1
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• 2011

This study analyzes transitions to a green path in transportation system in South Korea. We develop transportation system model with four new technology options, green cars; Hybrid electric vehicle, plug-in hybrid vehicle, electric vehicle and fuel cell vehicle. Among those technologies fuel cell vehicle is the best option assuming no GHG emissions when driving. We use MESSAGE model to get an optimal solution of pathway for high deployment of fuel cell vehicles under the Korea BAU transportation model. Among hydrogen production sources, off gas hydrogen is most economic since it is hardly used to other chemical sources or emits in South Korea. According to off gas hydrogen projection it can run 1.8 million fuel cell vehicles in 2040 which corresponds to 10% of all passenger cars expected in Korea in 2040. However, there are concerns associated with technology maturity, cost uncertainty which has contradictions. But clean pathway with off gas and renewable sources may provide a strong driving force for energy transition in transportation in South Korea.

• 대한공간정보학회지
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• 제3권2호
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• pp.199-211
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• 1995

본 연구는 대중교통 활성화에 초점을 맞추어 대중교통의 주축을 이루고 있는 지하철과 버스를 중심으로 연계버스 서비스 권을 설정하는 방법을 제시하였다. 연계권역설정은 지하철과 버스의 상호보완적 체계를 이루어 도시체계의 비용손실을 최소화하는데 그 목적이 있으며, 이는 지하철을 중심으로 첨두시 향도심성 대중교통이용자들이 버스로 직접 도심통행시와 인접지하철역까지 버스를 이용하여 환승으로 도심통행시의 편익을 감안한 모형과 그 해법을 제시하였으며, 권역구획은 범용 GIS Package의 IDRISI를 이용하였다.

• International Journal of Railway
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• 제9권1호
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• pp.1-9
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• 2016

In order to achieve a comprehensive utilization of railway networks, it is necessary to accurately assess the timetable indicators that effect the train operation. This paper describes the parameter calibration for two timetable indicators: scheduled running time and scheduled dwell time. For the scheduled running time, an existing model is employed and the single timetable parameter (percentage of minimum running time) in that model is optimized. For the scheduled dwell time, two intrinsic characteristics: the significance of stations and the average headway at each station are proposed firstly to form a new model, and the corresponding timetable parameters (the weight of the significance and the weight of the average headway) are calibrated subsequently. The Floyd Algorithm is used to obtain the connectivity among stations, which represents the significance of the stations. A case study is conducted in a light rail transportation system with 17 underground stations. The results of this research show that the optimal value of the scheduled running time parameter can be automatically determined, and the proposed model for the scheduled dwell time works well with a high coefficient of determination and low relative root mean square error through the leave-one-out validation.