• Proceedings of the KSR Conference
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• 2010.06a
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• pp.947-953
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• 2010

The KTX-Sancheon has been commercially operating on the high-speed line since March. 2. In order to verify the performance of high-speed train and core equipments such as current collection system, sophisticated tests and evaluating procedures should have been considering. In this paper, the load cell with a built-in strain-gauge which developed to improve measuring method of contact force between the pantograph and catenary system is introduced. The static test results of the load cell shows that its design is very suitable and applicable for the dynamic test and on-line test. After the test and evaluation of load cell's dynamic calibration with pantograph, we will be applied to test interaction characteristics between the pantograph and catenary system on the high-speed line.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.281-285
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• 2002

A new method of dynamic contact force measurement between a pantograph and a contact wire is proposed in this paper The method does not require design modification of an original pantograph in order to install sensors such as load cells. Contact forces can be expressed as the sum of vertical shear forces at the support points and inertial forces. Using specially-designed strain gage rosettes. vertical shear forces at the supported points can be measured without noise mixing and thermal effects. In order to obtain contact forces from shear forces, 3 inertial force compansation methods are proposed and compared in this paper. By validation process, the new proposed measurement method is verified to be applicable to the on-line current collection test.

• Korean System Dynamics Review
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• v.11 no.3
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• pp.87-104
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• 2010

This research aims at designing policy alternatives which would facilitate the supply of the national rental housing units, especially targeted for the low-income households who need special types of social support for their residences. In order to illuminate structural characteristics of the national rental housing policies, it heavily depends on collection of secondary survey data, in addition to existing documents. From the institutional dimension, it focuses on major issues related to the residential development, which is pivotal in supplying the required national rental housing units. Furthermore, applying causal loop diagramming techniques derived from the System Dynamics (SD), it tries to divulge dynamic relationships between key stakeholders including the government, developers and tenants. Finally, this research stresses the point that the government should fulfill its basic duty as a financial supporter and the developer should not procrastinate in providing diverse options, timely reflecting tenants' needs.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.151-158
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• 1999

In this study, we developed the simulation program of an overhead catenary-pantograph system, The overhead catenary is modeled with point mass and the pantograph is replaced with 3 d. o. f. model which is composed of mass, spring and damper. Using the developed program, we analyzed the static structure of the overhead catenary and the dynamic characteristics of an overhead catenary-pantograph system such as uplift displacement of contact wire and contact force. we compared the analysis results with the results of GASENDO software developed at RTRI in Japan. The behaviors of uplift displacement of contact wire and contact force were similar with the results of GASENDO software.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.3-7
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• 2003

The dynamics of the pantograph motion and contact forces of the high-speed railway are investigated through signals. acquired during a test run. The signals are obtained from accelerometers, load cells, and strain gauges attached to various positions of the pantograph, and they are processed in time-and frequency-domains to evaluate the dynamic characteristics and load forces. The natural frequencies of the pantograph is found to be 8.5Hz. There also are frequency components varying linearly with the train speed. The signal frequency components above 40Hz are attenuated as they pass through the primary and secondary suspensions.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1195-1198
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• 1993

We investigate a systematic design procedure of automated rule generation of fuzzy logic based controller for uncertain dynamic systems such as an engine dynamic model.“Automated Tuning”means autonomous clustering or collection of such meaningful transitional relations in the state-space. Optimal control strategies are included in the design procedures, such as minimum squared error, minimum time, minimum energy or combined performance criteria. Fuzzy feedback control systems designed by the cell-state transition method have the properties of closed-loop stability, robustness under parameter variabtions, and a certain degree of optimality. Most of all, the main advantage of the proposed approach is that reliability can be potentially increased even if a large grain of uncertainty is involved within the control system under consideration. A numerical example is shown in which we apply our strategic fuzzy controller design to a highly nonlinear model of engine idle speed contr l.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.494-497
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• 2004

A dynamic simulation for a high-speed pantograph-overheadline has been performed using mode superposition method to predict contact forces between pantograph and overheadline. We can deal with non-linear dampers of the pantograph and pre-sag of overhead-line for the simulation. But, we can not consider slackness of dropper in the overhead-line. According to the simulation results, the contact forces and displacements are reasonably predicted, compared with other foreign simulation results.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.1
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• pp.152-159
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• 2005

The dynamic properties between catenary and pantograph of high-speed train are very important factors to affect the stable electric power supply. So as to design the reliable current collection system, a multibody simulation model is needed. In this paper, the dynamic analysis method for a pantograph-catenary cable system of high-speed train is presented. The very deformable motion of a catenary cable is demonstrated using nonlinear continuous beam theory, which is based on an absolute nodal coordinate formulation, and the pantograph is modeled as a rigid multibody. The proposed method might be very efficient, because this method can present the nonlinear properties of a flexible catenary cable and set a various boundary conditions.

• Journal of Communications and Networks
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• v.18 no.6
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• pp.938-947
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• 2016

A mobile ad hoc network (MANET) is a collection of mobile nodes communicating in an infrastructure-less environment without the aid of a central administrating authority. Such networks entail greater dependency on synergy amongst the nodes to execute fundamental network operations. The scarcity of resources makes it economically logical for nodes to misbehave to preserve their resources which makes secure routing difficult to achieve. To ensure secure routing a mechanism is required to discourage misbehavior and maintain the synergy in the network. The proposed scheme employs a partially distributed dynamic model at each node for enhancing the security of the network. Supplementary information regarding misbehavior in the network is partially distributed among the nodes during route establishment which is used as a cautionary measure to ensure secure routing. The proposed scheme contemplates the real world scenario where a node may exhibit different kinds of misbehavior at different times. Thus, it provides a dynamic decision making procedure to deal with nodes exhibiting varying misbehaviors in accordance to their severity. Simulations conducted to evaluate the performance of the model demonstrate its effectiveness in dealing with misbehaving nodes.

• Journal of Information Science Theory and Practice
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• v.11 no.2
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• pp.67-81
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• 2023

This paper presents a dynamic development of an ontology-based statistical information system supporting the collection, storage, processing, analysis, and the presentation of statistical knowledge at the national scale. To accomplish this, we propose a data mining technique to dynamically collect data relating to citizens from publicly available data sources; the collected data will then be structured, classified, categorized, and integrated into an ontology. Moreover, an intelligent platform is proposed in order to generate quantitative and qualitative statistical information based on the knowledge stored in the ontology. The main aims of our proposed system are to digitize administrative tasks and to provide reliable statistical information to governmental, economic, and social actors. The authorities will use the ontology-based statistical information system for strategic decision-making as it easily collects, produces, analyzes, and provides both quantitative and qualitative knowledge that will help to improve the administration and management of national political, social, and economic life.