• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.208-213
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• 2015

This study presents the estimation method for the optimal capacity of BESS(Battery Energy Storage System) in order to reduce the electric charges of common consumer. The daily optimal charge and discharge plan of BESS which satisfies the given constraints is established using linear programming through the change of rated output/rated capacity of the time that shows the electric charges in the highest reduced rate has been selected. There will be a problem to compare only reduced rate because the bigger the rated capacity, the more reduced rate is increased. Therefore, rated output/rated capacity of the time when the reduced amount of electric charges for a year is higher than the investment cost of BESS was selected.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.567-575
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• 2014

In recent times, an obvious strategy in liner shipping markets that has come to the fore is slow steaming. Nowadays, most liner shipping companies have decelerated the voyage speed to 15-18 knots on major routes, and some leading liner shipping companies have a plan to reduce it to below 15 knots. Slow steaming is helpful in reducing the operating cost and the amount of greenhouse-gas emissions on a single vessel with lower fuel consumption. However, it also creates various negative effects such as the opportunity cost, additional fixed costs and an in-transit inventory cost on a loop. Hence, the net operating cost on a loop is changing dynamically due to the changes of voyage speed based on various slow steaming effects. The aim of this study is to analyze the slow steaming effects in the liner shipping, and to find the best voyage speed that minimizes the operating cost on a loop. Moreover, this study suggests the recommendable strategy for liner shipping companies. To achieve the aim of this study, a simulation model has been designed using System Dynamics.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1418-1422
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• 2006

The project of advanced urban transit system development is developing the advanced vehicle and the core technologies for the cost down by system change, the transport safety and the environmental friendliness and the improvement of passenger service. The product data management system is installed for management of each project. Various data and informations producted from each project are made for database. Therefore, we develop the product data management system.

• Journal of Korean Society of Transportation
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• v.30 no.1
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• pp.149-159
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• 2012

The evaluation of public transit service quality is more complicated than evaluating other aspects of transportation service. Although various measures of effectiveness [MOEs] for transit service have been studied and applied, a more comprehensive and accurate MOE is still required. In the past, either data from user surveys or the experience of bus agency administrators and/or engineers used to measure the quality of service. However, recently, with reliable and accurate real time data from BMS(Bus Management System) and BIS(Bus Information System), more reliable and accurate MOEs are available. This study develops a service evaluation model from users' perspectives, which is based on user' cost models that consider passenger access time, riding time, waiting time, and discomfort due to in-vehicle overcrowding, violation of traffic laws, and accident rate. For validating proposed model, data from the BMS and transit-fare cards (T-Money Card) for Seoul's No. 472 main bus line were used. Models developed in this study provided reliable results.

• Journal of Korean Society of Transportation
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• v.30 no.1
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• pp.125-133
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• 2012

This paper deals with the passenger transfer trips counted from smart bus-card data from Seoul transit network to understand the current operational condition of the system. Objective of this study is to relocate the location of the transit transfer centers. It delivers a bi-level programing model. The upper model is a linear 0-1 binary integer program having the objective of total travel cost minimization constrained by the number of transfer centers and the total construction budget. The lower model is an user equilibrium assignment model determining the passengers' route choice according to the transfer center locations. The proposed bi-level programming model was tested in an example network. The result showed that the proposed was able to find the optimal solution.

• Journal of Korean Society of Transportation
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• v.19 no.5
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• pp.61-70
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• 2001

The origin and destination(O-D) matrix is one of the most important elements in transportation planning process. Traditionally, transport planners survey the O-D movements in order to estimate the O-D matrix. Even though the cost of the O-D survey requires high amounts of resources, the accuracy is relatively low. Therefore, many researchers have studied the estimation of the O-D matrix for automobile from traffic counts. however, there is a little attention for the application on the transit O-D matrix estimation from traffic counts. The objective of this study is therefore the estimation of the transit O-D matrix from traffic counts using Gradient method. which is verified by the reliability analysis using a contrived small example network.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.671-677
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• 2011

A diversity of railway network function enhancement projects such as the double tracking, electrification, and direct operation have been actively executed to improve the railway service. When the new rapid transit is provided, how many people will use it instead of other transports? How will the railway choice behavior be changed? Accordingly, in this paper, the applicability of diverted travel demand forecast methods, by Revealed Preference(RP) and Stated Preference(SP) data was reviewed for Daegu metropolitan rail rapid transit service. As the result of combining RP and SP data, including the sequential and simultaneous approach, the total travel time and travel cost parameters are of the right sign and are highly significant. The simultaneous approach is more efficient in terms of the estimation of coefficients. In particular, methods to improve validity of the Mixed RP/SP models, when RP data is used proportionally, the diverted travel demand can be easily identified by railway fare and travel time service level. Therefore, it is considered that this will practically apply even in other regions as well as Daegu metropolitan railway.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.82-96
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• 2020

The Demand Responsive Transit (DRT) system is the flexible public transport service that determines the route and schedule of the service vehicles according to users' requests. With increasing importance of public transport systems in urban areas, the development of stable and fast routing algorithms for DRT has become the goal of many researches over the past decades. In this study, a new heuristic method is proposed to generate fast and efficient routes for multiple vehicles using demand clustering and destination demand priority searching method considering the imbalance of users' origin and destination demands. The proposed algorithm is tested in various demand distribution scenarios including random, concentration and directed cases. The result shows that the proposed method reduce the drop of service ratio due to an increase in demand density and save computation time compared to other algorithms. In addition, compared to other clustering-based algorithms, the walking cost of the passengers is significantly reduced, but the detour time and in-vehicle travel time of the passenger is increased due to the detour burden.

• Journal of the Korean Society for Railway
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• v.11 no.4
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• pp.424-432
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• 2008

This paper presents theoretical explanations about the spill-over effects of domestic production of light rail transit and empirically investigates its effects on output, value-added and employment in the Korean economy. We distinguish net gains of domestic production from gross effects that bring about whether localized or imported cars are used. The input-output analysis is employed to fully capture the interaction among various industries involved. The empirical results reveal that net gains of domestic production such as import substitution, improvement of trade balances, and increase in output, value-added and employment are enormous. The cost reduction in construction, E&M systems, cars, management, and tariff and transportation is also significant.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.671-678
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• 2002

In this paper, we propose hierarchical inter-domain load balanced QoS routing in a large scale of network. And a scheme of calculating resources'costs for precomputation schemes in hierarchical routing is proposed, and a scheme for selecting a path among multiple precomputed paths is proposed. We also propose a QoS routing scheme for transit and intra traffic in a large scale of domain-based network. For a domain in the network, the routing scheme first precomputes K multiple paths between all pairs of ingress and egress border routers while considering balancing of the expected load then selects paths with the probability of path selection. The routing scheme combines inter and intra domain routings seamlessly and uses the same cost calculation scheme. And these schemes make possible both global network resources' utilization and also load balancing.