• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.131-134
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• 2018

Structural equation modeling is pointing to statistical procedures that simultaneously perform path analysis and confirmatory factor analysis. Today, this statistical procedure is an essential tool for researchers in the social sciences. There are as (AMOS, LISREL and PLS) representative tools that can perform structural equation modeling analysis. AMOS provides a convenient graphical user interface for beginners to use. PLS has the advantage of not having a constraint on normal distribution as well as a graphical user interface. Therefore, we compared and analyzed the three most commonly used tools in social sciences. This study suggests practical and theoretical implications based on the results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.4
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• pp.5-12
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• 2001

This paper presents the simulation methodology of the interior noise of vehicle using the frequency response function based hybrid modeling of the system which consists of multi-subsystem models obtained by the test or analysis. The complex systems such as a trimmed body of high modal density and a powertrain were modeled by using experimental data, and a sub-frame of a vehicle of low modal density was modeled by finite element data. Modeling of the whole system was executed and validated in the two stages. The first stave is combining the trimmed body and the sub-frame, and the second stage is attaching the powertrain, which is a exciting source, to the combined model of the first stage. The input force to the system was modeled as an equivalent force in the virtual space, which was obtained from impedance method using the FRFs of the powertrain and the responses. The interior noise predicted by the proposed method was very close to the direct measurement, which showed feasibility of the proposed modeling procedure. Since the methodology is easily applied to both the transfer path analysis of structure-borne noise and the analysis of noise contribution of a sub-system, it is expected to be a strong tool for design change of a vehicle in the earlier stare.

• Korean Journal of Computational Design and Engineering
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• v.14 no.1
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• pp.18-24
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• 2009

This paper proposes an analytical method of evaluating the maximum error by modeling the exact tool path for the tool traverse singular region in five-axis machining. It is known that the NC data from the inverse kinematics transformation of 5-axis machining can generate singular positions where incoherent movements of the rotary axes can appear. These lead to unexpected errors and abrupt operations, resulting in scoring on the machined surface. To resolve this problem, previous methods have calculated several tool positions during a singular operation, using inverse kinematics equations to predict tool trajectory and approximate the maximum error. This type of numerical approach, configuring the tool trajectory, requires much computation time to obtain a sufficient number of tool positions in a region. We have derived an analytical equation for the tool trajectory in a singular area by modeling the tool operation into a linear and a nonlinear part that is a general form of the tool trajectory in the singular area and that is suitable for all types of five-axis machine tools. In addition, we have evaluated the maximum tool-path error exactly, using our analytical model. Our algorithm can be used to modify NC data, making the operation smoother and bringing any errors to within tolerance.

• Physical Therapy Korea
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• v.15 no.3
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• pp.53-61
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• 2008

The purpose of this study was to examine the path analysis of factors related to musculoskeletal diseases of shipbuilding workers by considering related factors synthetically. The survey was completed by 1,536 shipbuilding workers and except for poor responses, 1,532 were analyzed. The survey consisted of questions about lifestyle, duration of service, physical and mental stress, and musculoskeletal diseases. The collected data was analyzed with SPSS/PC+ (a descriptive statistics program) and with AMOS 4.0 (a statistical program for path modeling) to test whether the hypothesized path model fitted the collected data. The results of the correlation analysis showed that musculoskeletal disease was associated with duration of service (r=-.095), physical stress (r=.077), and mental stress (r=.602). The results of the hypothesized path model satisfied the criteria required in relation to fitting the collected data. Musculoskeletal disease was directly affected by mental stress but not by physical stress, duration of service and life style. Thus, it is suggested that reducing mental stress is a strategy for the prevention for musculoskeletal disease.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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• pp.168-177
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• 2008

Path finding is a key element in the navigation of a mobile robot. To find a path, robot should know their position exactly, since the position error exposes a robot to many dangerous conditions. It could make a robot move to a wrong direction so that it may have damage by collision by the surrounding obstacles. We propose a method obtaining an accurate robot position. The localization of a mobile robot in its working environment performs by using a vision system and Virtual Reality Modeling Language(VRML). The robot identifies landmarks located in the environment. An image processing and neural network pattern matching techniques have been applied to find location of the robot. After the self-positioning procedure, the 2-D scene of the vision is overlaid onto a VRML scene. This paper describes how to realize the self-positioning, and shows the overlay between the 2-D and VRML scenes. The suggested method defines a robot's path successfully. An experiment using the suggested algorithm apply to a mobile robot has been performed and the result shows a good path tracking.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.64-66
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• 2003

본 연구에서는 병리진단 시 참여자들의 지식과 의견을 효과적으로 교환할 수 있는 온톨로지를 구축하고. 구축한 온톨로지를 기반으로 진단절차를 전산화하는 PathOnt 시스템을 개발하였다. PathOnt 시스템은 재활용 가능한 온톨로지를 사용함으로써 여러 전문가들 간의 의사소통과 지식공유의 문제를 극복하였으며, 다 층위로 구현하여 웹 어플리케이션으로써의 비전도 제시하였다

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.699-703
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• 1993

When the error path can be modeled as a pure delay, an adaptive algorithm for slowly time varying system is proposed to minimize the sound pressure level. This algorithm makes it possible to use the fittered-x LMS algorithm with on-line delay modeling of the error path. Another simple adaptive algorithm for pure tone noise is proposed which eliminates the cross term in the multiple error filtered-x LMS algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.674-682
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• 2003

This paper presents the studies on wireless channel modeling and reverse link synchronization of CATV. This paper analyzes multi-path fading channel to the cause of signal distortion in the wireless communication environment. We represent the microwave link characteristics according to the channel model. Multi-path channel can affect fading.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.427-431
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• 1996

A modeling of the dynamics of two cooperating robot manipulators doing assembly job such as peg-in-hole while coordinating the payload along the desired path is proposed. The system is uncertain due to the unknown mass and moment of inertia of the manipulators and the payload. To control the system, a robust control algorithm is proposed. The control algorithm includes fuzzylogic. By the fuzzy logic, the magnitude of the input torque of the manipulators is controlled not to go over the hardware saturation with keeping path tracking errors bounded.

• Journal of KSNVE
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• v.10 no.5
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• pp.792-799
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• 2000

Aircraft noise in the vicinity of Kimpo international airport has damaged to large number of people who live in communities. This paper investigates noise exposed area due to aircraft flight based on prediction modeling program INM and flight path data. Especially effect on route for aircraft has been considered. Ti also examines noise impact for various flight modes, such as a thrust cutback climb method.