• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.191-201
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• 2008

It has been employed TRANSYT-7F and NETSIM to evaluate the validity and effectiveness of improvement on TSM(Transportation Systems Management). But T7F is hard to describe platoon compression and dispersion in actually, and NETSIM takes a long time for network coding, calibration and have difficulty in setting up saturation flow. While Shockwave Model have advantage which can describe platoon compression and dispersion in actually and shorten hours, convenience of application. But Shockwave Model apply unrealistic traffic flow relation ship(U-K curve) and simplify platoon because of difficulty in calculating shockwave's position and cross. For solving limitation of existing shockwave models, It develop new model with 2-regime linear model, New platoon model, Extended shockwave, etc. For verifying the validity of the proposed model, it was compared with delay of T7F and NETSIM by offset variation. In conclusion, it is thought that proposed model have outstanding performance to simulate traffic phenomenon.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.359-364
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• 2003

The loss of potential opportunity profit which is consisting in the partial markups of the corporation would taking placed in related with the time-delay deeply, has customarily disregarded in contract adjustment under the principles of denial of cost accounting method, declined conjecture in the point of benefits and protection of the law in scope of compensation and the restricted conditions of constant contract. It is being resulted from that the policies of the general principles of accounting standards which is subjected to ask an objective data and evidence, and the denial system as a debt derived from imperfect legal theory applied by current law. Therefore, it is necessitated to find if any irrationality in the positive system is and further to draw an improved reasonable measures to adopt by review of constant system preparing tile reasonableness with the method of suitable quantification devices provided that any time-delay is induced by the party.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.2
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• pp.143-150
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• 2003

An improved MPPT converter with current compensation method for small-scaled PV-applications is presented in this paper. The proposed method implements maximum power point tracking (MPPT) by variable reference current which is continuously changed during one sampling period. Therefore, the Power transferred to the load is increased above 9% by the proposed MPPT converter with current compensation method. As a result, the utilization efficiency of Photovoltaic (PV)-panel can be increased. In addition, as it doesn't use digital signal processor (DSP), this MPPT method has the merits of both a cost efficiency and a simple control circuit design. Therefore, it is considered that the proposed MPPT method is proper to low power, low cost PV-applications. The concept and control principles of the proposed Un moth()d are explained in detail and its validity of the proposed method is verified through several simulated results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.26-32
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• 2007

A simple but accurate equivalent circuit of an aperture-coupled cavity-fed microstrip patch antenna is developed. It consists of ideal transformers, admittance elements, and transmission lines, and the related circuit element values are computed by applying the reciprocity theorem and complex power concept with the spectral-domain immittance approach. After validating by the published design example, a dual-band antenna was designed with the help of a hybrid optimization method. For this purpose, the Genetic Algorithm is applied with the Nelder-Mead simplex method. The obtained good results show that this approach turned out to be a very efficient tool for the design of aperture-coupled cavity-fed microstrip patch antenna having various structural design parameters.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.487-492
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• 2006

컴퓨터 네트워크의 발전에 의해 학습 공간의 시공간적인 확대와 교육 현장에서 교수-학습 과정에 대한 새로운 교수방법을 요구되었고, 유무선 방송, 인터넷 등을 이용하여 다양한 형태의 원격교육이 구체화되어 왔다. 하지만, 현재 운영되는 대부분의 원격교육시스템은 실질적인 학습 상황에서 단방향적인 개별 학습 형태를 보이고 있고, 사용자간의 쌍방향 상호작용을 위해서는 교수자나 학습자에게 일정 수준이상의 기술적 소양과 경제적 부담을 요구한다. 또한 교수자에게는 교수-학습 상황에서 발생하는 학습자 행동에 대한 실시간적인 모니터링과 학습자의 학습과정에 대한 평가의 어려움을, 학습자에게는 자기 반성의 기회를 제대로 제공하지 못하는 문제점을 안고 있다. 이에 본 연구에서는 원격교육에서의 협동학습 지원, 사용자의 기술적, 경제적 부담의 제거, 학습 전(全) 과정에 대한 원활한 모니터링과 피드백 기회의 제공을 목적으로 원격협동학습 시스템을 설계하고, 이를 개발하였다. 본 연구에 의해 개발된 원격협동학습 시스템은 원격협동학습을 지원하는 네트워크 화이트보드, 학습 과정 및 결과를 자연어로 저장하는 저장 모듈, 그리고 저장된 학습 스크립트 파일을 해석하여 재생하는 스크립트 인터프리터로 구성되었다. 네트워크 화이트보드는 소프트웨어적으로 구현되어 부가적인 장치가 불필요하고, 통신 서버를 분산하여 서버 구축에 대한 부담을 제거하였고, 학습 내용 화면을 대화창으로 사용하여 사용자의 사용 편리성을 제고하였다. 또한 원격학습의 장(場)에 교수자가 참여하여 실시간적 모니터링이 가능하고, 학습의 전(全) 과정 및 결과를 저장한 자연어 스크립트 파일에 의해서도 학습자 행동에 대한 모니터링이 가능하다. 저장된 자연어 스크립트 파일은 구현된 인터프리터를 이용한 재생뿐 아니라, 파일 자체만으로도 학습과정을 판독할 수 있고, 스크립트 파일에 대한 해석은 교수자에게는 학습자의 학습 과정에 대한 평가 및 피드백의 근거를, 학습자에게는 자신의 학습 행동에 대한 반성의 기회를 제공한다. 본 시스템은 기존의 원격교육시스템에 비해 장비 및 인터페이스 측면에서 간소화되었고, 원격교육에 면대면 학습 개념을 근사적으로 접목시킨 교수 모델로서의 충분한 가치를 제공하나, 실제적인 학습 적용과 효과에 있어서의 타당성은 차후 검증이 있어야 하고, 또한, 이에 따른 시스템에 대한 지속적인 보완도 필요하다.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.731-737
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• 2012

In the present study, a feasibility study on an innovative satellite attitude control actuator is performed. The actuator is specially designed to generate the reaction torque in an arbitrary axis, so that a satellite attitude can be controlled by using itself. It consists of a spherical flywheel and electromagnets for levitation and rotation control of the ball. As the earlier study, a rotating performance test on the spherical actuator is conducted in a single rotating axis and vertical levitation condition. From the test results, it can be confirmed that the maximum speed and torque of the innovative device are 7,200rpm and 0.7Nm, respectively. Using a velocity-voltage characteristic curve of the spherical motor, an open-loop control (V/f constant control) is performed, and the test results show excellent control performance in acceleration and deceleration phases.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1246-1256
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• 1998

MIB(Management Information Base), one of the key components of network management system, is a conceptual repository for the information of the various managed objects. MIB stores and manages all the structural and operational data of each managed resources. Therefore, MIB should be protected properly from inadvertant user access or malicious attacks. International standard ISO/IEC 10164-9 describes several managed object classes for the enforcement of MIB security. Those managed object classes described access control rules for security policy. But the exact authorization procedures using those newly added managed object classes are not presented. In this paper, we divide managed object classes into two groups, explicit and implicit ones, and describe the access authorization procedure in Z specification language. Using Z as a description method for both authorization procedure and GDMO's action part, the behaviour of each managed object class and access authorization procedure is more precisely and formally defined than those of natural language form.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.1 no.1
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• pp.71-80
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• 1989

In this paper, the concept of the infinite element is applied to the linear wave diffraction and radiation problems. The hydrodynamic pressure forces are assumed to be inertially dominated, and viscous effects are neglected. The near field region surrounding the solid body is modelled using the conventional finite elements, and the far field region is represented using the infinite elements .In order to represent the scattered wave potentials in the far field region more accurately, the infinite elements are developed using special shape functions derived from the asymptotic expressions for the analytical eigenseries solution of the scattered waves. The system matrices of the infinite elements are constructed by performing the integration in the infinite direction analytically to achieve computational efficiency. Numerical analyses are carried out for vertical axisymmetric bodies to validate the infinite elements developed here. Comparisons with the results by other available numerical solution methods show that the present method using the infinite elements gives fairly good results. Numerical experiments are per-formed to determine the suitable location of the infinite elements and the appropriate size of the finite elements which directly affect accuracy and efficiency of the solution.

• Journal of Information Management
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• v.35 no.2
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• pp.57-85
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• 2004

This is the comparative study about analyzing the methodologies of building ontology with IEEE Standard 1074-1997. The methodologies are chosen to be analyzed. They are OTK, CommanKADS, ONIONS and Noy & McGuinness's Ontology Development 101. On the basis of analyzing, the ontology development process is proposed after the strong points of four methodologies are accepted but the weak points of them are supplemented. The sixth development steps are following: 1) Conducting the feasibility study about ontology building as the pre-development process 2) Setting up the purpose of the ontology development as the starting point of the building 3) Considering the integration of the existing ontologies for the knowledge reuse 4) Constructing the ontology by defining the concepts and relations 5) Evaluating and testing the ontology for the completeness 6) Containing the ontology maintenance for the sustainable use.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.4 no.1
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• pp.71-80
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• 2010

This study developed the perspective model of behavior of physical therapists(PTs) and occupational therapists(OTs) who are dealing with confidential patient medical information in hospitals. Theory of planned Behavior(TpB) model, expanded models 1 and 2 that add habit, social pressure, and work convenience concept to TpB are tested for the validity in explaining the preposing factors that affect the behavior of PTs and OTs in ensuring the confidentiality of patient medical records. Data were collected by administrating a survey to the 120 PTs and OTs in A city. Of the 120 questionaries distributed, 110 were responded resulting 91.6% of response rate. There were not significantly different among the group classified by age, 'clinical career, gender, work family, and education level were analysis using with Independent t test and one-way ANOVA. The relationships on the concepts suggested in the models were analysed by applying the Structured Equations Modeling methods. The results of Structured Equations analysis showed that expanded model 2 was more effective model than TpB model and expanded model 1.