• 산업경영시스템학회지
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• 제35권2호
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• pp.57-63
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• 2012

소프트웨어 개발에 있어서 소프트웨어를 시장에 출시하는 계획을 수립하는 것은 소프트웨어를 이루고 있는 기능들을 구현하는 데 제약이 되는 조건들(기술, 자원, 위험, 예산 등)을 만족하면서 계획된 출시기간에 이들 기능들을 할당하는 일이다. 이와 같이 소프트웨어 출시를 계획하는 것은 소프트웨어 제품라인에 대해서 고려할 때 더욱 복잡해진다. 본 연구에서는 소프트웨어 제품라인에 있어서 소프트웨어 출시 계획을 수립하기 위한 문제를 우선순위 제약하의 다수 0-1 배낭문제로 수리 모형화하고, 이를 풀기 위한 최적해법이 개발된다. 최적해법은 동적 계획법이 주가 되고, 문제의 크기를 줄이기 위하여 휴리스틱과 축소방법이 이용된다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.253-259
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• 1997

A software for design of turbine bearings has been developed based on both the theoretical analysis and experimental investigation. Static and dynamic performance, i.e. load capacity, frictional loss, temperature distribution, stiffness and damping coefficients, stability etc., can be obtained by using this software taking into account the effects of three dimensional variation of lubricant viscosity, turbulence and inlet pressure. A performance test rig was developed by self-design and technology, which was used to verify static and dynamic characteristics and to investigate the proper boundary conditions for theoretical analysis. Consequently HANJUNG has developed the self-design technology for design of turbine bearings for power plants.

• Computers and Concrete
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• 제20권3호
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• pp.297-310
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• 2017

A CFD software was used to simulate free surface flow of SCC in the T-Box test. In total, seven simulations were developed to study the effect of rheological parameters on the non-restricted flow performance of SCC in both horizontal and vertical directions. Different suspending fluids having five plastic viscosity values between 10 and 50 Pa.s, three yield stress values between 14 and 75 Pa, one density of $2500kg/m^3$, and one shear elasticity modulus of 100 Pa were considered for suspension of 178 spherical particles of 20-mm diameter and $2500kg/m^3$ density. The results of the simulations are found to correlate well to changes in rheological parameters of the suspending fluid. Plastic viscosity was shown to be the most dominant parameter affecting flowability and dynamic stability compared to the yield stress. A new approach was proposed to evaluate performability of SCC based on a trade-off between flowability and dynamic stability.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권1호
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• pp.50-57
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• 2017

Purpose : This paper is a comparative analysis results of the fatigue test for dental implants and accelerated life test by using a static type loading device commonly used in Korea and a dynamic type loading device (universal-joint) recommended by FDA. Methods : Fatigue tests of dental implant is based on ISO 14801 and classified into static load test and dynamic load test. The tests were carried out on three test specimens by four load stress steps under each loading device. For analysis on failure mode such as crack, fracture and permanent deformation of test specimens, we used X-ray three-dimensional computed tomography on test specimens before and after the fatigue tests. The design of the accelerated life test was based on the analysis results of the fatigue life data obtained from the dynamic load test and the statistical analysis software (Minitab ver.15) was used to analyze the appropriate life distribution. Results : As a result of the fatigue tests and the accelerated life tests at same acceleration condition under each test method, the fatigue life under the dynamic type loading device (universal-joint) was shorter than when static type loading device was applied. Conclusion : This paper can be used as a reference when the universal-joint type loading device for implants fatigue test is applied as ISO 14801.

• Journal of Positioning, Navigation, and Timing
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• 제8권1호
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• pp.1-12
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• 2019

In this paper, we implement a navigation software of a Global Navigation Satellite System (GNSS) receiver based on a commercial purpose GNSS software receiver platform and verify its performance by performing experimental tests for various GNSS signals available in Korea region. The SX3, employed in this paper, is composed of an application program and a Radio Frequency (RF) frontend, and can capture and process multi-constellation and multi-frequency GNSS signals. All the signal processing procedure of SX3 is accessible by the receiver software designer. In particular for an easy research and development, the Application Programing Interface (API) of the SX3 has a flexible architecture to upgrade or change the existing software program, equipped with a real-time monitoring function to monitor all the API executions. Users can easily apply and experiment with the developed algorithms using a form of Dynamic Link Library (DLL) files. Thus, by utilizing this flexible architecture, the cost and effort to develop a GNSS receiver can be greatly reduced.

• 정보처리학회논문지D
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• 제11D권3호
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• pp.649-658
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• 2004

객체지향 시스템은 상호 작용하늘 객체들의 집합으로 구성되었고 시스템의 행위는 객체들의 협력 행위로 표현된다. 객체지향 소프트웨어의 상속성, 다형성 등 특성들은 소프트웨어 테스팅에 어려움을 증가시키고 객체의 병행성, 동적바인딩, 상호작용 등 동적인 면들은 프로그램의 실행 시간에 한 멤버 함수의 호출에 의해 여러 멤버함수로 바인딩될 수 있다. 그러므로 객체지향 소프트웨어의 특성들을 고려하고 동시에 객체들간의 상호착용을 테스트하기 위한 연구가 필요하다 이 논문에서 상속성, 다형성 등 특성을 고려하여 평탄화된(Flattened) 상태차트 다이어그램을 구성하고, 시스템 모델링과 시뮬레이션에 전형적으로 사용되는 CPN(Colored Petri net)으로 모델링 한 후 Design/CPN 툴에 적용하여 객체지향 소프트웨어 객체들간의 상호작용 테스트를 자동화할 수 있는 테스트 레이스 생성 기법을 제안한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.109-111
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• 1996

This paper describes real time dynamic tests on the digital distance relay using new digital test system including RTDS(Real Time Digital Simulator) in KEPRI. The RTDS is developed by the Manitoba HVDC Reserch Centre and consists of specialized hardware and software which allows transients simulation of electrical power systems in real time. From high impedance fault test, it is known that the characteritics of distance reach is influenced by load flow. A detailed discussion of relay test using the RTDS simulator, high impedance faults and test results are included in the paper.

• 한국전산구조공학회논문집
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• 제21권1호
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• pp.59-71
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• 2008

본 논문에서는 지진하중하의 대형구조물의 시뮬레이션을 위해 실험과 해석을 병합한 분산공유 하이브리드 해석 및 실험소프트웨어 framework를 개발하였다. 제안된 소프트웨어 framework은 별도의 동적 그리고 정적 해석을 위한 프로그램의 개발이 필요 없기 때문에 일반 범용 유한요소해석 프로그램을 개발된 해석 및 실험 제어 프로그램과 interface API를 이용하여 사용할 수 있는 장점이 있다. 본 논문에서 개발된 소프트웨어 framework은 독자적 기능을 가진 module로 구성이 되어 있을 뿐만 아니라 개체지향형 프로그램 개념을 바탕으로 개발되었다. 예제를 통하여 개발된 시스템의 기능과 분산공유하이브리드 해석 및 실험에서의 유용성을 증명하였다.

• 한국자동차공학회논문집
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• 제7권9호
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• pp.105-111
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• 1999

The paper presents development of a Hardware-In-the-Loop simulation (HILS) system for the purpose of testing performance, stability, and reliability of an electronic power steering system(EPS). In order to realistically test an EPS by the proposed HILS apparatus, a simulated uniaxial dynamic rack force is applied physically to the EPS hardware by a pnumatic actuator. An EPS hardware is composed of steering wheel &column, a rack & pinion mechanism, andas motor-driven power steering system. A command signal for a pneumatic rack-force actuator is generated from the vehicle handling lumped parameter dynamic model 9software) that is simulated in real time by using a very fast digital signal processor. The inputs to the real-time vehicle dynamic simulation model are a constant vehicle forward speed and from wheel steering angles driven through a steering system by a driver. The output from a real-time simulation model is an electric signal that is proportional to the uniaxial rack force. The vehicle handling lumped parameter dynamic model is validated by a fully nonlinear constrained multibody vehicle dynamic model. The HILS system simulation results sow that the proposed HILS system may be used to realistically test the performance stability , and reliability of an electronic power steering system is a repeated way.

• Structural Engineering and Mechanics
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• 제37권6호
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• pp.593-615
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• 2011

This study determines the water length effects on the modal behavior of a prototype arch dam using Operational and Analytical Modal Analyses. Achievement of this purpose involves construction of a prototype arch dam-reservoir-foundation model under laboratory conditions. In the model, reservoir length was taken to be as much as three times the dam height. To determine the experimental dynamic characteristics of the arch dam using Operational Modal Analysis, ambient vibration tests were implemented for empty reservoir and three different reservoir water lengths. In the ambient vibration tests, the dam was vibrated by natural excitations provided from small impact effects and the response signals were measured using sensitive accelerometers. Operational Modal Analysis software process signals collected from the ambient vibration tests, and Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification techniques estimated modal parameters of the dams. To validate the experimental results, 3D finite element model of the prototype arch dam was modeled by ANSYS software for empty reservoir and three different reservoir water lengths, and dynamic characteristics of each model were determined analytically. At the end of the study, experimentally and analytically identified dynamic characteristics compared to each other. Also, changes on the natural frequencies along to water length are plotted as graphs. Results suggest that reservoir water complicates the modal behavior of the arch dam significantly.