• 시스템엔지니어링학술지
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• 제12권1호
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• pp.41-58
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• 2016

Reliability Centered Maintenance (RCM) introduces a systematic method and decision logic tree for utilizing previous operating experience focused on reliability and optimization of maintenance activities. In this paper RCM methodology is applied on safety injection system for APR-1400. Functional Failure Mode Effects and Criticality Analysis (FME&CA) are applied to evaluate the failure modes and the effect on the component, system and plant. Logic Tree Analysis (LTA) is used to determine the optimum maintenance tasks. The results show that increasing the condition based maintenance will reduce component failure and improve reliability and availability of the system. Also the extension of the surveillance test interval of Safety Injection Pumps (SIPs) would lead to an improved pump's availability, eliminate the unnecessary maintenance tasks and this will optimize maintenance activities.

• 교육시설
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• 제10권1호
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• pp.15-22
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• 2003

The library of elementary schools, which plays a role in the basic education to grow a responsible social member in an information society and to develop ability for collection, selection, summary, and utilization of various information, could be considered as new educational center. It should be changed to the establishment of informational education for preparing the information society in 21st century through the functional extension of the conventional library as reading and bookstand. Furthermore, it is necessary of trials that converts to the support system for interchange between establishment and student, for preparing educational system of teaching or studying, and for opening establishment to local communities in the future.

• 전자공학회논문지S
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• 제34S권11호
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• pp.114-125
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• 1997

This paper presents a method that automatically recognizes dimension sets from the mechanical drawings, and that classifies 6 types dimension sets according to functional purpose. In the proposed method, the object and closed-loop symbols are separated from the character-free drawings. Then object lines and interpretation lines are vectorized. And, after recognizing dimension sets(consistings of arrowhead, shape line, tail lines, extension lines, text-string, and feature control frame), we classify recognized dimension sets as horizontal, vertical, angular, diametral, radial, and leader dimension sets. Finally the proposed method converts classified dimension sets into AutoCAD data by using AutoLisp language. By using the methods of geometric modeling, the proposed method readily recognized and classifies dimension sets from complex drawings. Experimetnal results are presented, which are obtained by applying the proposed method to drawings drawn in compliance with the KS drafting standard.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2001년도 제6차 학술대회 초록집
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• pp.104-104
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• 2001

Purpose： In this study, we investigated the possible motor pathways of hemiplegic stroke patients usin combined TMS and BOLD fMRI approach and evaluated the correlation between TMS a fMRI methods. Method： Four subjects, who demonstrated left hemiplegia after stroke, are included. TMS was performed using a Dantec Mag2 stimulator (Dantec Company, USA) in single puls mode with figure eight-shaped coil. Following TMS localization, The BOLD T2＊-weight images were acquired with echo planar imaging sequence (TR = 1.2 sec, TE = 60 msec, and flip angle = 90). Motor activation was studied by means of a repetitive fing flexion-extension task. The stimulation protocol comprised 10 cycles of alternating activati and rest (10 images per cycle). Total 60 cycles were performed and each cycle take abou 1.5 sec. The resulting images were then analyzed with STIMULATE (CMRR, U, o Minnesota) to generate functional maps using a student t-test (p < 0.0005) and cluste analysis.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.215-218
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• 1999

A general structural model, which is an extension of the Vlassov theory, is developed for the analysis of composite rotor blades with elastic couplings. A comprehensive analysis applicable to both thick-and thin-walled composite beams, which can have either open- or closed profile is formulated. The theory accounts for the effects of elastic couplings, shell wall thickness, and transverse shear deformations. A semi-complementary energy functional is used to account for the shear stress distribution in the shell wall. The bending and torsion related warpings and the shear correction factors are obtained in closed form as part of the analysis. The resulting first order shear deformation theory describes the beam kinematics in terms of the axial, flap and lag bending, flap and lag shear, torsion and torsion-warping deformations. The theory is validated against experimental results for various cross-section beams with elastic couplings.

• Advanced Composite Materials
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• 제18권2호
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• pp.105-119
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• 2009

In this work, the structural response of thin-walled composite beams with pretwist angle is investigated by using a mixed beam approach that combines the stiffness and flexibility methods in a unified manner. The Reissner's semi-complimentary energy functional is used to derive the stiffness matrix that approximates the beam in an Euler-Bernoulli level for extension and bending and Vlasov level for torsion. The bending and torsion-related warpings induced by the pretwist effects are derived in a closed form. The developed theory is validated with available literature and detailed finite element structural analysis results using the MSC/NASTRAN. Pretwisted composite beams with rectangular solid and thin-walled box sections are illustrated to validate the current approach. Acceptable correlation has been achieved for cases considered in this study. The effects of pretwist and fiber orientation angles on the static behavior of pretwisted composite beams are also studied.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.2004-2009
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• 2003

The purpose of this study is to define how wrist motion is affected by different postures and supporting devices and to discover functional range of wrist motion for keyboard typing. The range of wrist motion (ROM) needed for fourteen experienced typists to type on a computer keyboard was measured by flexible and biaxial electrogoniometers. The most frequent wrist motion during typing was in extended and ulnarly deviated positions in both wrists. Range of wrist motion was similar in both wrists. The average ROM for keyboard typing with the typists' own posture was about 39 in flexion/extension (FEM) and 29 in radial/ulnar deviation (RUD) in both wrists. The range of wrist motion was significantly reduced to 30 in FEM and 27 in RUD with use of either wrist or forearm supporting devices, which suggests that these devices might help to relieve fatigue, discomfort, or pain during and/or after typing. Results of this study will be of interest to clinicians and helpful to those who are professionally or non-professionally involved in typing.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.235-239
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• 1992

The paper describes an approach for estimating unsteady flow rate through oil hydraulic pipelines and components in real time. Recently we have proposed following three unsteady flow rate measurement approaches; RIFM, QIFM and TPFM, in which hydraulic pipeline dynamics are made use of. In this paper, we firstly propose new approaches, i.e, an interpolation and an extrapolation methods in combination with RIFM and TPFM. In the interpolation method, unsteady flow rate at the arbitrary internal location along the pipeline between two points for measuring the two point pressure can be estimated. In this paper, the accuracy and dynamic response of interpolation method are mainly experimentally investigated in detail.

• Communications for Statistical Applications and Methods
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• 제24권4호
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• pp.367-382
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• 2017

We consider an infinite-order long-memory heterogeneous autoregressive (HAR) model, which is motivated by a long-memory property of realized volatilities (RVs), as an extension of the finite order HAR-RV model. We develop bootstrap tests for structural mean or variance changes in the infinite-order HAR model via stationary bootstrapping. A functional central limit theorem is proved for stationary bootstrap sample, which enables us to develop stationary bootstrap cumulative sum (CUSUM) tests: a bootstrap test for mean break and a bootstrap test for variance break. Consistencies of the bootstrap null distributions of the CUSUM tests are proved. Consistencies of the bootstrap CUSUM tests are also proved under alternative hypotheses of mean or variance changes. A Monte-Carlo simulation shows that stationary bootstrapping improves the sizes of existing tests.

• 한국주거학회논문집
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• 제1권1호
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• pp.27-35
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• 1990

In the course of modernization coupled with industrialization and urbanization. Maru or wooden floor and Teachong or great hall of Han-ok or traditional Korean housing has experienced functional as well as physical changes to a remarkable degree. The author made an analysis of the transfiguration of Maru/Taechong space(M/T) with relation to: 1)Madang or yard. 2)Anbang or inner room, 3)Hyon-kwan or vestibule. 1) In relation to Madang, interiorization of M/T by way of setting sliding glass doors has begun to appear. 2) In connection with Anbang, division of role/function is being observed as far as family entertainment and reception of intimate friends is concerned. 3) Owing to wider acceptance of Hyon-kwan space as a buffer zone system, the advent of Keo-sil or living room is thought to be facilitated. The analysis, however, does not say that Keo-sil of modernized Korean housing might well be interpreted as the mere extension type of M/T of the vernacular housing.