• 경영과학
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• 제34권1호
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• pp.1-13
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• 2017

The percentage of 3PL (Third-party Logistics), which uses third party businesses to outsource elements of the company's distribution and fulfillment services, is increasing steadily. To provide 3PL service to the customers, it is needed to estimate the total transportation cost and propose the unit cost to the customers. In this paper, we develop a decision support system for estimation of transportation cost of 3PL provider considering various transportation services, such as direct transportation, multi point visiting transportation, and cross docking. The system supports route planning of vehicles by using algorithms based on tabu search and dynamic programming.

• 한국ITS학회 논문지
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• 제20권1호
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• pp.119-131
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• 2021

경부고속도로는 서울과 부산을 연결하는 국토대동맥으로써 여객과 화물수송의 역할 뿐 만아니라 산업과 도시발전에 영향을 주었다. 본 연구는 1970년 개통한 경부고속도로가 사회경제적으로 미친 직접적인 효과를 정량적으로 도출하였으며, 보다 신뢰성 있는 결과도출을 위하여 과거 시점의 네트워크 구축 및 O/D교통량추정, 편익계수의 보정방법론을 제시하였다. 1970년 당시 경부고속도로가 미건설된 경우, 경부고속도로 개통이 10년 지연된 경우, 세계은행의 제안과 같이 경부고속도로 대신 서울~대전, 또는 서울~강릉 간 유료도로가 개통되는 경우의 시나리오를 설정하였으며, 각 시나리오와 현재의 차량운행비용, 통행시간비용, 교통사고비용, 환경오염비용을 산정·비교하여 직접편익을 추정하였다. 분석 결과를 통해 1970년 경부고속도로 개통은 10년 지연되었을 때와 비교하여 약 351조의 직접편익이 발생하는 것으로 추정되었으며, 이는 당시 경부고속도로 건설사업 추진이 우리나라 사회경제에 막대한 영향을 주었다는 것을 알 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.196-200
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• 2003

To fulfill the railroad station's duties efficiently, it is essential to view passenger transfer system within the railroad station and in the vicinity of railroad station in the context of broader technological developments in easy access to railroad station. To do the direct service to local station or easy transfer to other mass transportation modes, necessary courses for local govemments and each transportation agency involvement should be taken and long-term integrated transfer strategy must be found. The research designed here was designed to derive a general overview of the integrated transfer patterns with an emphasis on passenger intermodal transportation system.

• 대한교통학회:학술대회논문집
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• 대한교통학회 2007년도 제56회 학술발표회논문집
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• pp.663-669
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• 2007

• 대한교통학회지
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• 제29권2호
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• pp.91-100
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• 2011

허브네트워크 설계는 수송량의 증가에 따라 단위 수송비가 감소하는 규모의 경제효과를 이용하여 네트워크의 총 물류비용을 최소화시키는 허브입지, 기종점별 수송경로를 결정하는 최적화과정이다. 본 연구에서는 비허브가 한 개의 허브에만 연결되고, 기종점간의 직결수송이 허용되지 않고 허브간 수송만을 허용하는 단일할당 제약 허브네트워크 설계를 통해 네트워크의 최적 허브입지를 제시하지 못했던 김남주 외 (2008)의 한계를 극복하여 최적 허브입지를 결정적으로 제시하였다. 허브집합 결정과정에서는 greedy-interchange algorithm을 사용하였고, 수송경로탐색에서는 EMME/2를 사용하였다. 우리나라 전국 도로수송 네트워크에 적용한 결과, 최적 허브입지는 수도권, 경남권, 충남권, 전남권, 경북권, 충북권 등의 순서로 선정되었으며, 수송의 간선축인 경부축에 집중되었다. 단일할당 제약 허브정책으로 각 기종점간 직접운송 대신에 허브를 경유하는 운송 방식을 취함으로써 운송거리는 증가했으나, 수송비용은 오히려 감소하였다. 또한 기종점-허브간 우회거리 단축으로 인한 수송비용 절감보다 허브간 수송량 분산으로 인한 규모의 경제효과 감소가 더 커 허브수가 늘어남에 따른 수송비용 감소폭은 점차 감소하였다. 본 연구는 GIS프로그램을 이용한 공학적 접근방법을 통해 국내 화물수송의 대부분을 차지하는 도로수송의 최적 허브입지와 수송경로를 결정적으로 제시한 것으로 국가물류비용을 절감하려는 정책적 측면에서 의미가 있을 것으로 판단된다.

• Asian Journal of Atmospheric Environment
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• 제10권1호
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• pp.51-56
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• 2016

Particulate matter (PM) in the atmosphere has wide-ranging health, environmental, and climate effects, many of which are attributed to fine-mode secondary organic aerosols. PM concentrations are significantly enhanced by primary particle emissions from traffic sources. Recently, in order to reduce $CO_2$ and increase fuel economy, gasoline direct injected (GDI) engine technology is increasingly used in vehicle manufactures. The popularization of GDI technique has resulted in increasing of concerns on environmental protection. In order to better understand variations in chemical composition of particulate matter from emissions of GDI vehicle versus a port fuel injected (PFI) vehicle, a high time resolution chemical composition of PM emissions from GDI and PFI vehicles was measured at facility of Transport Pollution Research Center (TPRC), National Institute of Environmental Research (NIER), Korea. Continuous measurements of inorganic and organic species in PM were conducted using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The HR-ToF-AMS provides insight into non-refractory PM composition, including concentrations of nitrate, sulfate, hydrocarbon-like and oxygenated organic aerosol, and organic mass with 20 sec time resolution. Many cases of PM emissions during the study were dominated by organic and nitrate aerosol. An overview of observed PM characteristics will be provided along with an analysis of comparison of GDI vehicle versus PFI vehicle in PM emission rates and oxidation states.

• Structural Engineering and Mechanics
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• 제86권5호
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• pp.607-619
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• 2023

This study, it was tried to evaluate the asphalt behavior under tensile loading conditions through indirect Brazilian and direct tensile tests, experimentally and numerically. This paper is important from two points of view. The first one, a new test method was developed for the determination of the direct tensile strength of asphalt and its difference was obtained from the indirect test method. The second one, the effects of particle size and loading rate have been cleared on the tensile fracture mechanism. The experimental direct tensile strength of the asphalt specimens was measured in the laboratory using the compression-to-tensile load converting (CTLC) device. Some special types of asphalt specimens were prepared in the form of slabs with a central hole. The CTLC device is then equipped with this specimen and placed in the universal testing machine. Then, the direct tensile strength of asphalt specimens with different sizes of ingredients can be measured at different loading rates in the laboratory. The particle flow code (PFC) was used to numerically simulate the direct tensile strength test of asphalt samples. This numerical modeling technique is based on the versatile discrete element method (DEM). Three different particle diameters were chosen and were tested under three different loading rates. The results show that when the loading rate was 0.016 mm/sec, two tensile cracks were initiated from the left and right of the hole and propagated perpendicular to the loading axis till coalescence to the model boundary. When the loading rate was 0.032 mm/sec, two tensile cracks were initiated from the left and right of the hole and propagated perpendicular to the loading axis. The branching occurs in these cracks. This shows that the crack propagation is under quasi-static conditions. When the loading rate was 0.064 mm/sec, mixed tensile and shear cracks were initiated below the loading walls and branching occurred in these cracks. This shows that the crack propagation is under dynamic conditions. The loading rate increases and the tensile strength increases. Because all defects mobilized under a low loading rate and this led to decreasing the tensile strength. The experimental results for the direct tensile strengths of asphalt specimens of different ingredients were in good accordance with their corresponding results approximated by DEM software.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.645-654
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• 2021

This research aims to examine the influence of road transportation infrastructure on the mobility of goods transport and the regional economy in Langkat Regency in Indonesia. This type of research is an associative and explanatory research whose data is obtained through a questionnaire survey. This study took a sample of 305 respondents using probability sampling in Langkat Regency, North Sumatera, Indonesia. Data analysis techniques use path analysis. The research results showed that the road transportation infrastructure variables had a significant and positive effect on the mobility of goods transport. Road transportation infrastructure and freight mobility simultaneously have a significant and positive effect on the economy of Langkat Regency. Road transportation infrastructure with the dimensions of road accessibility and maintenance partially directly has a significant and positive effect on the economy of the Langkat Regency. Road transportation infrastructure with the dimensions of road design and road construction quality partially does not have a direct effect on the regional economy, but has a positive and significant effect through the mobility of freight transport. The mobility of goods transport becomes an intervening variable that acts to mediate or determine the relationship between road transportation infrastructure variables to the regional economy.

• 무역학회지
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• 제44권6호
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• pp.303-325
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• 2019

The purpose of this study is to determine optimal transportation routes through the comparison of Korean - European transportation routes of automotive parts and to suggest information that can be utilized in Korea - Europe trade activities or trade route selection by establishing multipath. This study analyzed the direct transportation cost, inventory cost, and warehouse inventory cost of the sea and TSR / TCR railroad transport based on characteristics of automotive parts logistics and multimodal transportation. Also, this study identifies the most effective transportation route from the viewpoint of total logistics cost. In addition to the economic factors, we conducted an in-depth analysis through interviews with corporate executives to identify the importance of the factors with the behavioral factors, and the reliability was further secured through interviews. Through this study, it is possible to understand various aspects of international logistics by analyzing the factors of transportation choice in terms of economic and behavioral perspectives concurrently by differentiating from existing research.

• 전력전자학회논문지
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• 제23권6호
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• pp.403-407
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• 2018

This study proposes a predictive direct power control method in a modular multilevel converter (MMC) high-voltage direct-current (HVDC) system. The conventional proportional integral (PI)-based control method uses a cascaded connection and requires an optimal gain selection procedure and additional decoupling scheme. However, the proposed control method has a simple structure for active/reactive power control due to the direct power control scheme and exhibits a fast dynamic response by predicting the future status of system variables and considering time delay. The effectiveness of the proposed method is verified by simulation results.