• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.159-166
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• 2010

Trip distribution is to connect travel demand for each OD pair based on travel cost, trip production and attraction derived from trip generation step. In real world the travel cost is a function of travel demand, but existing models could not fully consider such functional relation between travel cost and demand, which leads to an equilibrium in trip distribution model. This paper proves the equilibrium trip distribution by using gravity model. In order to obtain such equilibrium this paper also presents a solution algorithm based on fixed point theorem. The algorithm will be tested with an example and confirmed the equilibrium solution of trip distribution.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.1047-1057
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• 2016

Design engineering process for field programmable gate array (FPGA)-based reactor trip functions are developed in this work. The process discussed in this work is based on the systems engineering approach. The overall design process is effectively implemented by combining with design and implementation processes. It transforms its overall development process from traditional V-model to Y-model. This approach gives the benefit of concurrent engineering of design work with software implementation. As a result, it reduces development time and effort. The design engineering process consisted of five activities, which are performed and discussed: needs/systems analysis; requirement analysis; functional analysis; design synthesis; and design verification and validation. Those activities are used to develop FPGA-based reactor bistable trip functions that trigger reactor trip when the process input value exceeds the setpoint. To implement design synthesis effectively, a model-based design technique is implied. The finite-state machine with data path structural modeling technique together with very high speed integrated circuit hardware description language and the Aldec Active-HDL tool are used to design, model, and verify the reactor bistable trip functions for nuclear power plants.

• Proceedings of the KOR-KST Conference
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• 1995.02a
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• pp.58-82
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• 1995

This study providesd an empirical analysis of trip-chaining behavior and its application to transportation planning. In the empirical analysis, changes in trip-chaining patterns since 1970 have been examined and details of current trip-chaining behavior as they describe shopping trip-chaining behavior has changed. Individual trip-chaining has become longer and complex. It appears that the average number of trips per chains has substantially increased over the past 20 years. An increased number of trips in chains means fewer home-based trips. Changes in trip-chaining behavior have several consequences. Important consequences are for transportation and land-use planning. Up to now trips have been treated as if they are independent clusters of home-to-destination-to-home; this approach has not usually taken into account the trip-chaining behavior of individuals. this calls for a different approach to at least the trip generation and trip distribution part of transportation planning. In this study, application of trip-chaining behavior to trip distribution model formulation is proposed and its calibration results are presented.

• Journal of Korean Society of Transportation
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• v.12 no.1
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• pp.43-54
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• 1994

The major concern of this paper is to investigate the properties of a stochastic equilibrium for each model system in terms of a consumer welfare measure. The primary assumption for this study is that a trip-maker would choose the trip from his origin zone which maximizes his personal welfare. This assumption, finally, leads to a singly constrained gravity model. The consumer welfare measure is derived from the concept of expected welfare of randomly sampled trip-makers. Each of the four different models considered in this paper is differentiated depending on the complexity of its model or the definition of its travel function. In this study, three different regions are chosen for the purpose of taking into account the effects of different zone-systems on the properties of a stochastic equilibrium : (i) Archerville region (5 zone) ; (ii) San Francisco Bay regions (30 zones) ; (iii) Houston, TX region (199 zones). It is concluded that almost identical, "global" consumer welfare values can be obtained in some cases of the gravity-type trip distribution models based on a stochastic equilibrium.

• Management Science and Financial Engineering
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• v.15 no.1
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• pp.51-69
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• 2009

A network model and a Genetic Algorithm (GA) is proposed to solve the simultaneous estimation of the trip distribution and traffic assignment from traffic counts in the congested networks in a logit-based Stochastic User Equilibrium (SUE). The model is formulated as a problem of minimizing a non-linear objective function with the linear constraints. In the model, the flow-conservation constraints are utilized to restrict the solution space and to force the link flows become consistent to the traffic counts. The objective of the model is to minimize the discrepancies between two sets of link flows. One is the set of link flows satisfying the constraints of flow-conservation, trip production from origin, trip attraction to destination and traffic counts at observed links. The other is the set of link flows those are estimated through the trip distribution and traffic assignment using the path flow estimator in the logit-based SUE. In the proposed GA, a chromosome is defined as a real vector representing a set of Origin-Destination Matrix (ODM), link flows and route-choice dispersion coefficient. Each chromosome is evaluated by the corresponding discrepancies. The population of the chromosome is evolved by the concurrent simplex crossover and random mutation. To maintain the feasibility of solutions, a bounded vector shipment technique is used during the crossover and mutation.

• Journal of Korean Society of Transportation
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• v.29 no.3
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• pp.7-19
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• 2011

Using 2006 metropolitan household travel survey data, this study analyzes trip behaviors based on a concept of trip chains using both trip purpose and number of trip linkages. For the analysis, trip chains are classified into two groups depending on including commute trips. Each group is further classified into a single linkage (i.e., Origin-Destination trips without any intermediate stop-by) and multiple linkages (Origin-Destination trip with at least one intermediate stop-by). The analysis is conducted using the two-step Nested Logit Model. Computational results identifying the characteristics of single and multiple linkages show that the young, male and office employee drivers tend to have more multiple linkages than single linkages in their trips. In contrast, it is shown that a driver whose monthly income is less than 3,000,000 Korean Won with a longer commute time more likely to make a trip chain with single linkages (p<0.0001).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.2
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• pp.68-79
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• 2014

This paper analyzes the characteristics of trip chaining activities of elderly and explores temporal and spatial distribution. The research also estimates ordered probit model and binary logistic model to investigate various factors affecting trip chaining and mode choice patterns. We utilized household survey data for elderly conducted in 2006 and 2010 in Seoul metropolitan area. Research results indicate that trip chaining showed an increasing trend and simple trip chaining counts for more than 85%. GIS mapping expressed spatial distribution of trip departure and arrival areas, particularly showing regional changes in job-related trips. We also found that more factors influence trip chaining in 2010, compared with 2006, and travel cost is more sensitive than travel time in determining travel mode. The research contributes to establish transportation policies based on travel behavior of elderly in a upcoming super-aged society.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.315-316
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• 2006

As IEC 61850 based substation automation technology is emerging globally, there are many efforts to implement and apply this IEC 61850 standard to substation automation area. IEC 61850 based substation supports ethernet network, standard data model and SCL(substation Configuration Language), etc. These features can provide enough environment to make applied technology which can substitute the legacy relay trip logic configuration method(PLC or Local area reconstruction) to XML based configuration method. This paper suggests new IED trip logic configuration method. The XML based trip logic configuration method can be established using SCL technology And IED trip logic reconfiguration from remote center can be possible under ethernet based technology

• The Journal of Information Systems
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• v.28 no.4
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• pp.49-64
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• 2019

Purpose The purpose of this paper is to observe the relative priorities of importances among IT services for Smart tourism as well as the relative priorities of importances among ways for developing the IT Services. Design/methodology/approach AHP analysis model was designed with 3 layers in order to recognize the relative importances priorities of IT services and the ways developing the IT services in Smart tourism. The factors in the top layer consist of Pre-trip IT services, During-trip IT services and Post-trip IT services. The lower factors in second layer of the Pre-trip IT services consists of Tourism information search, Online reservation and Price comparison. The lower factors of the During-trip IT services consists of Context recognition, Virtual Reality and Drone Application. The lower factors of the Post-trip IT services consists of Interactive Sharing and Tagging. The factor of third layer, the ways of developing the IT services consist of Company leading, University leading and Industry-University Collaboration. The structural questionnaire based on the AHP analysis model was designed and used to survey experts in IT and tourism areas. The collected data by the question investigation was analyzed by AHP analysis technique. Findings The importance priority of During-trip IT service was highest among in the three type IT services of tourism life cycle. The importance priority of Price comparison service was highest among IT services for Pre-trip. The importance priority of the Context recognition service was highest among IT services for During-trip. The Interactive sharing service was highest among IT services for Post-trip. It would be confirmed for the IT service development ways of Company leading to be suitable for most of the It services, such as Tourism information search, Online reservation, Price comparison, Context recognition, Virtual reality, Drone application, Interactive sharing.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.126-139
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• 2011

In the traditional four-step travel demand models, each step is sequentially conducted following the model estimation at the previous step. The accuracy of the following model is partly dependent on whether the model at the former stage was properly established or not. Therefore, trip generation, which is the first step in this conventional model, has great effects on the modeling process and forecasting results. Linear regression models for trip generation of Seoul Metropolitan Area might increase the forcasting errors, since a variety of land-use characteristics are not considered. Hence, in this study, zonal factors such as socioeconomic and land use variables are included to improve the elaboration of trip generation. Comparing the %RMSE with the existing models, which contain bigger errors in the zones highly based on the secondary and tertiary industries than residence-based, the trip generation models including those variables seem more appropriate overall.