• Structural Engineering and Mechanics
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• v.82 no.1
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• pp.41-53
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• 2022

We developed an accurate and simple vibration model to calculate the natural frequencies and their corresponding vibration modes for multi-span beam bridges with non-uniform cross-sections. A closed set of characteristic functions of a single-span beam was used to construct the vibration modes of the multi-span bridges, which were considered single-span beams with multiple constraints. To simplify the boundary conditions, the restraints were converted into spring constraints. Then the functional of the total energy has the same form as the penalty method. Compared to the conventional penalty method, the penalty coefficients in the proposed approach can be calculated directly, which can avoid the iteration process and convergence problem. The natural frequencies and corresponding vibration modes were obtained via the minimum total potential energy principle. By using the symmetry of the eigenfunctions or structure, the matrix size can be further reduced, which increases the computational efficiency of the proposed model. The accuracy and efficiency of the proposed approach were validated by the finite element method.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2077-2081
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• 2011

Recently the train indusrty come to the fore because of Punctual, eco-friendly transportation system and becoming the main transportation. The construction plans for the trian depot for train's maintenance and storage increase constantly. For past few years, there were many construction plans, Bubal train depot, Gwangju train depot, Duckha train depot. Proper track distribution plan is important to carry out the design of railway depot for efficient maintenance operation and train storage. Through the proper design of track distribution plan, we can shorten the moving time, train movement distance, waiting time in train depot. In this paper, the verification of the track distribution plan's efficiency and appropriateness for railway depot as Bubal train depot's plan is studied and analyzed with the train depot management simulation program-Posrail(v1.0).

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1596-1602
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• 2010

The government have plans to improve the railway transport capacity and transport hub for the sustainable national transport and logistics system. Specially, there are much efforts to improve transportation capacity such as high speed transportation of rail freight, enlargement of BT train, development of double stack train, etc. between railway transport hubs. If the transport capacity between railway logistics hubs is increased as planned, we must increase the handling capacity of railway hub terminals. But there are limits to enlarge the terminal infrastructure because of investment scale, location circumstances and urban development plans. To ensure the capacity, with the minimum required enlargement of infrastructure, it is necessary to extremely increase the efficiency of terminal operations. For improving the efficiency, we have to introduce the efficient terminal operation systems based on u-IT and operation optimize technologies. In this paper, we analyse the issues and problems of railway terminals(including ICD) and suggest the concept of intelligent railway terminal and the construction components of technology.

• International Commerce and Information Review
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• v.9 no.2
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• pp.285-303
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• 2007

As the interest about smooth logistics increases lately, the importance of multimodal transport, which performs the key role of logistics emerges, Through there are many issues respecting multimodal transport, the issue of the efficiency of multimodal transport seems to be the most importance. This paper examine as to the problems & systems of the multimodal transport including transportation document and customs clearance for door to door services. I wish our country will use total logistics automation systems for encouraging multimodal transport chance and make a partial amendment of commercial code including the customs clearance regulation. This study will assist in the development of logistic and the enlargement of multimodal transport transaction.

• Journal of Korean Society of Transportation
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• v.14 no.2
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• pp.45-58
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• 1996

In a large signal intersection, it is the most important to set phase sequences and phase intervals of traffic signal in order to improve the efficiency of the capacity as well as safety. These setting allows to select the best sequence of signal phase among several alternatives, and thus to rearrange the starting and ending points of the individual phase using an effective interphase periods (EIP). The EIP is a gap between previous and current traffic movements at a potential collision point in an intersection. Each of traffic movements has an equality for safety and efficiency at the balanced condition of EIP. This paper presents how to set optimally the phase sequences and intervals of traffic signal in an intersection using phase based approach. And in the second part, we applied the theory developed in the first part. In particular, a numerical example of phase base signal setting is presented using a matrix computation method in order to select the best sequence among several alternatives, and thus to rearrange the starting and ending points of the individual phase using the EIP. This method also allows to apply to optimum signal setting even in five-lag or staggered-type intersection.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1574-1586
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• 2008

Railway is the most effective transportation than any other traffic. But due to the its expensive maintenance fee and various components like roadbed, rail, rollingstock, electric and signal etc, the construction cost of the railway is usually higher than highway. Such a reason, a lot of cost and period are needed to complete the railway project. In addition that considering the decreasing of the SOC budget, the investment in the railway industry is getting hard than ever. This study analyzed the cost, term of work, freight & passenger transportation demand of the wide area railway electrification project and main line improvement project. And it compared the estimation value and real value of the projects like cost and period etc. And this study surveyed the economic feasibility including factors which are not considered in the feasibility study guide. With those results, This study suggest the project management and evaluation method to enlarge the efficiency of the railway construction project.

• Korean Management Science Review
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• v.33 no.1
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• pp.89-99
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• 2016

A scheduled airlift is the most critical part of the air transportation operations in ROK Air Force. The military cargo-plane routing problem is a PDPLS (pickup and delivery problem in which load splits and node revisits are allowed). The cargo which is transported by a military cargo-plane is measured in pallet. The efficiency of pallet needs to be considered with respect to its volume and weight. There are some guidelines about orders of priorities and regulations in the military air transportation. However, there are no methodologies which can raise the efficiency of flight scheduling using Operations Research (OR) theories. This research proposes the effective computing methodology and the related heuristic algorithms that can maximize the effectiveness of the path routing model.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.463-469
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• 2016

This paper presents a compression-friendly low power test scheme in EDT environment. The proposed approach exploits scan slices reusing to reduce the switching activity during shifting for test scheme based on linear decompressor. To avoid the impact on encoding efficiency from resulting control data, a counter is utilized to generate control signals. Experimental results obtained for some larger ISCAS'89 and ITC'99 benchmark circuits illustrate that the proposed test application scheme can improve significantly the encoding efficiency of linear decompressor.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.94-102
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• 2012

In this paper, an interactive planning and scheduling framework are proposed for optimising operations from pits to crushers in ore mining industry. Series of theoretical and practical operations research techniques are investigated to improve the overall efficiency of mining systems due to the facts that mining managers need to tackle optimisation problems within different horizons and with different levels of detail. Under this framework, mine design planning, mine production sequencing and mine transportation scheduling models are integrated and interacted within a whole optimisation system. The proposed integrated framework could be used by mining industry for reducing equipment costs, improving the production efficiency and maximising the net present value.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3566-3582
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• 2019

In intelligent warehouse picking system, the allocation of tasks has an important influence on the efficiency of the whole system because of the large number of robots and orders. The paper proposes a method to solve the task allocation problem that multi-robot task allocation problem is transformed into transportation problem to find a collision-free task allocation scheme and then improve the capability of task processing. The task time window and the power consumption of multi-robot (driving distance) are regarded as the utility function and the maximized utility function is the objective function. Then an integer programming formulation is constructed considering the number of task assignment on an agent according to their battery consumption restriction. The problem of task allocation is solved by table working method. Finally, simulation modeling of the methods based on table working method is carried out. Results show that the method has good performance and can improve the efficiency of the task execution.