Daejeon, South Korea
Daejeon, South Korea

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Ha O.-K.,Korail Research Institute | Song Y.-S.,Korea Institute of Construction Technology | Chung K.-Y.,Sangji University | Lee K.-D.,Yonsei University | Park D.,University of Seoul
Personal and Ubiquitous Computing | Year: 2014

The development of information technology has rapidly changed the logistics industry. RFID has become more and more important in the context of supply chain management (SCM), and implementation of RFID in SCM brings with it the potential to manage the information flow and to support communication and collaboration along the supply chain. This study was conducted to build a relation model, which is a structural model, to identify the effects of introducing RFID into the supply chain of the food and beverage industry in Korea. The supply chain of the food and beverage industry was divided into five activities: procurement, production, transport, sale, warehousing, and administration. This study was based on the premise that RFID will be embedded in a transport box or pallet circulated in the SC. The model showed that SC activities have positive relationships through the RFID system, and the introduction of RFID promotes information interchanges between SC activities, which in turn enable the coordination and consolidation of a total SCM. From the results of this study, it is expected that the RFID system does not only enable the SC partners to improve their utilities but also promotes the efficiency of SCM as a whole. This is meaningful considering that there is still a controversy regarding the effects of RFID on SCM. © 2013 The Author(s).


Shin S.,Inha University | Koo M.-S.,Inha University | Lee H.-K.,Dong Bu Engineering Co. | Kwon S.-J.,Korail Research Institute
Bridge Maintenance, Safety, Management and Life-Cycle Optimization - Proceedings of the 5th International Conference on Bridge Maintenance, Safety and Management | Year: 2010

Variations of the natural frequency of a prestressed concrete (PSC) girder bridge due to the applied prestressing force are investigated. A finite element formulation for the undamped dynamic motion of a beam-tendon system is derived based on the principle of virtual work. The linear geometric stiffness component of a beam due to the tendon force and that of a taut string due to the prestressing force are separately added to the bending stiffness of the beam. The proposed dynamic equation of motion has been verified through a comparison of the analytical results with those obtained from the results of laboratory experiments available in the literature, which shows significant variation in the natural frequencies due to the prestressing force. The proposed algorithm has been applied to the analysis of actual PSC girder bridges with prestressing. The analytical results show that the variation of the first natural frequency due to the prestressing force is negligibly small in actual PSC bridges, since the added stiffness due to the prestressing is negligible in actual applications. © 2010 Taylor & Francis Group, London.


Park H.,University of Seoul | Park D.,University of Seoul | Kim C.,Korea Transport Institute | Kim H.,KORAIL Research Institute | Park M.,Inha University
Canadian Journal of Civil Engineering | Year: 2013

One of the major issues when applying truck destination choice models with a large number of alternatives is how to sample a set of non-chosen traffic analysis zones (TAZs) to construct a destination choice set. Despite the large number of studies applying various sampling strategies, the question remains as to what are optimal strategies in model development. This study examined how the sampling strategies affect the performances of truck destination choice models. Two sampling methods (simple random sampling and stratified importance sampling) and four different sample sizes were tested using the truck trip data of Korea. For stratified importance sampling, Moran's I statistics were used to divide the entire study area into multiple strata, and Neyman allocation was used to determine the appropriate number of samples for each stratum. The truck trip productions were distributed by a Monte Carlo simulation, and two measurements of effectiveness (MOEs), average trip length (ATL) and trip length distribution (TLD), were used to evaluate and compare the performance of the destination choice models with respect to the sampling strategy. The results showed that the models using stratified importance sampling with smaller sample sizes performed better than others.


Kim J.-W.,KORAIL Research Institute | Yu S.-N.,Korea Atomic Energy Research Institute
International Journal of Precision Engineering and Manufacturing | Year: 2013

The main purpose of this paper is to select a design variable that can maintain a stable current collection despite changes of span lengths during operation. For the purpose of improving the current collection of the pantograph system, we used a robust design method with tools to select an optimal design variable. As the robust design requires a simulation of selected factors based on the tables of an orthogonal array, it is necessary to configure a numerical model for analyzing a pantograph system. In this study, we induced an equation of motion by implementing a linear 3DOF model in terms of system interpretation. Then, we figured out a time varying stiffness of catenary within a given speed range by configuring a finite element model of the catenary system, and analyzed the contact force by span and speed. Then, we intended to select an optimal combination of design variables that can improve the current collection while high-speed trains are driving. To that end, we came to utilize the robust design method as a kind of optimization technique. Robust design includes the array of signal factors and control factors onto the tables of an orthogonal array and analyzes an S/N ratio and sensitivity as a result of output response characteristics for each design variable level. According to these results, we selected an optimal level of design variables that are likely to improve the current collection. Consequently, we conducted a simulation on selected design variables to check if they have an effect on reducing vibration. By doing so, we managed to confirm their reproducibility. © 2013 Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.


Ha O.,KORAIL Research Institute | Park M.,Inha University | Lee K.,Yonsei University | Park D.,University of Seoul
KSCE Journal of Civil Engineering | Year: 2013

The advancement of Information Technology (IT) has efficiently and systematically changed most of all industry activities. With the increased implementation of IT in logistics, the implementation of Radio Frequency Identification (RFID) in logistics could enable the improvement of supply Chain Capacity (SC) and play an important role in the procurement of resources, production, transport, loading and unloading, warehouse, etc., consisting of Supply Chain Management (SCM). This study identifies how composition factors have an effect on SCM efficiency and the intention of implementing RFID according to the implementation of RFID into the food-beverage industry. In addition, this study attempts to reveal the contributing factors affecting the intention of implementing RFID into food-beverage companies by using the intention determination model for implementing RFID and analyzing data characterizing those companies. Based on nine hypotheses produced according to the implementation of RFID into the food-beverage industry, Confirmatory Factor Analysis (CFA) and Structural Equation Model (SEM) were used for achieving the goals of this study. As the analysis results of this study indicate, the implementation effects of RFID into SCM showed not a unidirectional influence relationship but a multidirectional and complicated influence relationship. © 2013 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg.


Ha O.,KORAIL Research Institute | Park D.,University of Seoul | Lee K.,Yonsei University | Won J.,Hanyang University
KSCE Journal of Civil Engineering | Year: 2011

The objective of this study is to identify evaluation criteria for evaluating residential area road networks. To this end, existing studies regarding urban plan paradigms, neighborhood road network designs and road network evaluation criteria are reviewed, leading to the selection through first and second expert questionnaire surveys of 42 road network evaluation criteria. The road network evaluation criteria were divided into interregional road networks and regional road networks. To derive the evaluation criteria, the former were divided into motorways (main roads and auxiliary main roads) and public transportation, while the latter were divided into motorways (distributed roads, local roads), pedestrian ways and bicycle ways. Analytical Hierarchy Process (AHP) analysis of the weighted values of the evaluation criteria revealed the regional road networks to be more important than the interregional road networks, and the eco-friendly transportation networks such as pedestrian ways and bicycle ways to be more important than others. The road network evaluation criteria were divided into quantitative and qualitative indicators, and the methods for their scoring were presented by considering the characteristics of each evaluation criterion. Finally, the practicality of these evaluation criteria was investigated with a case study that examined a residential area redevelopment project of the "Jeonnong · dapshim-ri rearrangement promotion". In the evaluation of the road networks before and after implementation of the development project, the evaluation scores of the interregional road networks did not show any significant differences, while the evaluation scores of regional road networks did. This result indicated that the conditions of the regional road networks, including motorways (distributed roads, local roads), were considerably improved by the case region development project. © 2011 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg.


Ha O.,Korail Research Institute | Choi B.-L.,Yonsei University | Kim Y.,Yonsei University | Kim B.,Korail Research Institute | Lee K.-D.,Yonsei University
Cluster Computing | Year: 2015

This study aimed to develop indicators and to establish a procedure that could be used in adjusting functions of a freight station based on many different characteristics of railway logistics. Even though previous studies had drawn optimal models using mathematical algorithms, there was a difficulty in applying those models. Those studies were limited in that they did not consider many different characteristics of railway logistics but were based only on the volume of freight transportation. This study established indicators and procedures by considering characteristics of railway logistics to increase the effectiveness in adjusting functions of the freight station and then analyzed changes in the freight transportation volume and efficiency according to function adjustment of the freight station. As a result, it was shown that the operating cost had decreased more than two-fold compared to the transport income via function adjustment of the freight station. © 2014, Springer Science+Business Media New York.


Chang M.S.,Korea Institute of Machinery and Materials | Choi B.O.,Korea Institute of Machinery and Materials | Lee J.H.,KORAIL Research Institute
Transactions of the Korean Society of Mechanical Engineers, A | Year: 2014

Reliability allocation is generally used during the early stage of system development to apportion the system reliability target to its individual modules. This paper presents a comprehensive method for performing the reliability allocation of KTX door systems. Nine criteria for reliability allocation include failure criticality, operating time, risk, complexity, failure rate, maintenance, manufacturing technology, working condition, and reliability cost. For satisfying the system reliability target, the allocated B10 lives of four modules are provided. © 2014 The Korean Society of Mechanical Engineers.

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