• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.688-694
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• 2018

The transition section of the overhead rigid conductor rail (ORCR) consists of a direct induction device and a limit point to prevent the power supply failure and failure of the electric railway vehicle pantograph due to the difference of the uplift in the catenary line. In T-Bar transition section, a twin simple catenary is mostly installed between the overhead catenary system (OCS) in the ground section and the ORCR in the underground section. In this paper, we compare and analyze the possibility of replacing the twin simple catenary with heavy simple catenary. The reliability of numerical analysis results was confirmed by comparing field test with numerical results. Comparing the numerical results of the twin simple catenary with the heavy simple catenary in the transition section, the difference uplift is 5.9[mm] on average. When applying heavy simple catenary instead of twin simple catenary, the slight difference of uplift can be compensated by adjusting the height of hanger-ear or support bracket.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.4
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• pp.733-739
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• 2017

Research on fuel cell systems attracting attention as an environmentally friendly energy source has been actively conducted. And research is being conducted on railway vehicles that use direct current power generated by a fuel cell as an energy source. In this paper, a two-phase interleaved bidirectional DC-DC converter has been proposed which can supply electric energy of a battery to a traction motor during powering and charge the battery with regenerative energy during braking. Therefore, the topology of the energy storage system applied to the railway vehicle was analyzed, and the simulation was performed by constructing the power conversion system by this topology. Experiments were also conducted through hardware design and fabrication based on the simulation analysis results, and the validity of the hardware implementation was verified.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.59-71
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• 2005

In this paper we address a design problem for hub and spoke transportation networks and then consider a capacitated hub locations problem with direct shipment (CHLPwD). We determine the location of hubs, the allocation of nodes to hubs, and direct shipment paths in the network, with the objective of minimizing the total cost in the network. An evolutionary algorithm is developed here to solve the CHLPwD. To do this, we propose the representation and the genetic operators suitable for the problem and adopt a heuristic method for the allocation of nodes to hubs. To enhance the search capability, problem-specific information is used in our evolutionary algorithm. The proposed algorithm is compared with the heuristic method in terms of solution quality and computation time. The experimental results show that our algorithm can provide better solutions than the heuristic.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.12
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• pp.169-181
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• 2021

The study aims to investigate the direct effects of business management practices in terms of financial, marketing, human resources, and logistics operations practices on sales revenue and profitability growth of freight forwarding businesses. A quantitative research design and partial least square-structural equation modeling were used to examine the direct effects of the exogenous and endogenous variables. The study reveals that financial, marketing, and human resources practices have a positive and significant effect on sales revenue growth. Furthermore, marketing and logistics operations have a positive and significant effect on profitability growth in the context of freight forwarding in the Philippines, particularly in its country's capital. As the current study only examines the direct effects of business management practices, other researchers may also want to consider identifying other variables as mediation and moderation to test other indirect effects on the financial performance of the business. The findings of the study can significantly benefit the freight industry to consider addressing other challenges or make use of the paper to further develop their strategies and practices to improve their financial performance.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.104-110
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• 2001

During the last several years, the high speed railway system has been constructed and it is scheduled to open sometime in 2004. To fulfil its duties, it is essential to view intermodalism in the context of broader technological developments in easy access to high speed railway station. And also, to understand the economic importance of intermodal transportation, continual research is needed on the costs and distributional effects of alternative intermodal mechanisms for public works, including direct service to local station or easy transfer to other mass transportation modes. In this paper, necessary courses for local governments involvement are taken, and additional resources must be found that will benefit the entire railway system.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1601-1606
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• 2004

Nowadays, the bus system of a metropolitan area is improving very fast. According to the bus, commuter railways increase their competitive power. For this, trains get the mobility increasing, effective transferring system and unified information service. For the mobility increasing, commuting railway must be faster by flexible train diagram and facilities improvement. And finally, optimal commuter train, 'Liner' is needful. And for effective transferring system, it is necessary that railway station and transferring center of a city be merged. And it is needful that direct management bus by railway company and unification fare system on metropolitan region. Next, for information service system improving, the commuting railway station must be regional transportation hub at first. And it is needful that unified line map of trunk line transportation systems and regionally collective transportation system information book. Therefore, metropolitan commuting railways compete with trunk line bus and cooperate with feeder line bus, and can make optimal metropolitan public transportation systems.

• East Asian Journal of Business Economics (EAJBE)
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• v.8 no.3
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• pp.43-56
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• 2020

Purpose - This study was carried out to analyze the influential factors of how consumers methodize purchasing agricultural products via direct market. It further utilizes the Discrete Choice Model to analyze consumer decision specifically with regards to individual markets and store attributes. Research design and methodology - This study will use the multinomial logit model to interpret the influential factors behind selecting a specific market to purchase from. This study establishes 'online direct-purchase' as the base category with 'direct farm markets', 'local foods direct markets', 'produce boxes (CSA)' as substitutes. Results - Firstly, the variety of products, price and freshness had a positive influence on choosing 'direct farm markets' while convenience of payment and transportation had a negative influence. Second, freshness and store attributes had a positive influence on choosing 'local foods direct markets' but product price and packaging, location accessibility had a negative influence. And although product creditability had a positive influence on purchasing 'produce boxes (CSA)', product price had a negative influence. Conclusions - Accordingly, there is a need for the South Korean government to encourage the adoption of mobile payment through smartphone applications in direct farm markets to vitalize direct agricultural purchasing. However, this does need to be approached cautiously as price has a conflicting affect for each method of purchase.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.218-222
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• 2013

Trade turnover between asia including our country and China and South America including Brazil the Chile is increasing continuously. That key item is diversified very from the raw materials to the agriculture and marine products, the industrial product and the mineral. The international transportation of these freight mainly depends in the aircraft and the container liner. But, in order to pass through the most various port of call is makes transshipment cargo and the long lead-time. so the goods expense of the style increases. The research proposed logistics network's construction between the main harbors of Korea and Ecuador. These nation according to great circle navigation is contiguous geographically in order to confront Pacific Ocean. These nation is contiguous geographically in order to confront Pacific Ocean by the great circle navigation. Specially Korea will become the hub-port of Northeast Asia and South America, which is caused by direct logistics lines's establishment.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.91-100
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• 2007

This study suggests direct connection service which has advantage of high-speed operation of KTX and access convenience of general train, and Pre-feasibility studies on the direct connection service. And analyze transportation demand change by the method as follows; It is to analyze the demand change of before and after KTX operation by previous transport data of Gyeongbu line, and calculate the coefficient of utilization using triggering demand by opening the 2nd phase of Gyeongbu line (Dongdaegu${\sim}$Busan). Through Pre-feasibility analysis, reduction $70{\sim}100$ minutes of train travel time and total revenue will increase about $100 thousand per day. Also, there will be environment-friendly effects of decreasing $CO_2$ emissions. But, Direct connection service need to highly cost ; Buying and Operation cost of KTX train. Therefore, we will be get more correct result of Pre-feasibility study on direct connection service, if there are concrete on buying the KTX action plans.

• Korean journal of food and cookery science
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• v.8 no.3
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• pp.323-332
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• 1992

This study was carried out to investigate work analysis by use of work sampling and productivity of school feeding at three elementary schools in Seoul. The results were as knows: 1. In the mean work percent of dietitians The direct work functions showed the highest, as the mean work percent was 40.4% for me direct work functions, 29.9% for me indirect work functions and 29.8% for me delays. Among the direct work functions, routine clerical was 30.9%, and receiving was 9.5%. 2. In the mean work percent of bakers The direct work functions (73.5%) marked the highest. Among those, cooking was 41.8%, transportation was 15.9%, and cleaning was 8.5%. 3. In the mean work percent of workers The direct work functions (781%) were me highest. Among those, the decreasing order was cooking (32.3%), cleaning (27.8%), and transportation (13.8%). 4. Work percent per labor hour The work percent per labor hour of dietitians was higher in the morning than in me afternoon, while they continued to work even during the lunch time. Bakers usually worked in me morning, but rarely worked in me afternoon. Workers had lunch and break time after their food service. In me school aided by parents volunteers, the total work time of workers was reduced by an hour and their work percent in me afternoon was high. 5. The number of mea1s served per labor hour was 32.6 meals, and me labor time spent per served mea1 was 1.8 minutes.