• 대한기계학회논문집A
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• 제30권8호
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• pp.976-984
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• 2006

Time-temperature superposition has been studied to determine the long-term fatigue life over millions of cycles for glassy polymers. π le superposition is supposed to make an accelerated lifetime testing (ALT) technique possible. Dog-bone shaped specimens made of carbon filled Polycarbonate (PC) were tested under fatigue, based on the stress-lifetime approach (S-N curve). Fatigue-induced localized yield-like deformation is considered as the defect leading to fatigue and its evolution behavior is characterized by a modified energy activation model in which temperature is considered as fatigue acceleration factor. This model allows the reduced time concept to account for effects of different temperature in short-term fatigue data to determine long-term fatigue life through the use of time-temperature superposition that is applicable under a low frequency and isothermal conditions. The experimental results validated that the proposed technique could be a possible method for accelerated lifetime testing (ALT) of time-dependent polymeric materials.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제10권2호
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• pp.125-133
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• 2004

개발 방법론과 도메인의 특성을 반영하여 테스팅 하기 위해서는 프로세스 표준을 테일러링 해야 하며 테일러링 된 프로세스에 따라 테스트를 수행해야 한다. 그러나 상용화된 테스트 도구들은 테일러링 된 프로세스의 일부만을 지원하기 때문에 실제 테스팅 현장에서는 개발 환경에 적합한 테스트 도구를 구입하거나 개발해야 한다. 본 논문에서는 프로덕트 라인 개발 개념을 이용한 테스트 프로세스 수행 도구 개발 방안을 제안하고 이를 ‘테스트 프로세스 수행 도구(Test Process Execution Tool: Test PET)’로 구현한다. 표준에 명시된 테스트 활동의 공통점과 차이점을 추출하여 이를 컴포넌트로 명세 및 구현하고 개발 방법론과 도메인에 맞는 특성을 반영하여 특정 개발 방법론과 도메인에 맞는 테스트 수행 도구를 개발하는 단계를 제안한다. 제안한 방안으로 구현된 Test PET은 개발 방법론과 도메인, 어플리케이션에 맞는 테스트 프로세스를 생성 한 후 생성된 테스트 프로세스에 따라 테스트를 수행할 수 있는 도구이다.

• 대한물리치료과학회지
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• 제18권1호
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• pp.33-49
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• 2011

The process of physical therapy uses a problem-solving approach to enhance a patients's functioning status. The International Classification of Functioning, Disability and Health(ICF) is the common concept for the functioning in the world. Physical therapists require the ability to identify problems, formulate hypothesis, and plan intervention strategies through clinical reasoning. In the clinical process, physical therapists need to use standard and common languages in speech and in documentation. The purpose of this study was to suggest the process of making strategy for efficient intervention, examining and evaluating the functional problem of the person with stroke using ICF tools. For the first step in this process model, therapists could list the information relating to functional problems used by the ICF Core set and then could identify the interaction among the problems using the ICF assessment sheet. For the next step, therapist is needed to make the hypothesis and hypothesis testing, and then set a primary functional goals and therapeutic goals in detail after prioritizing the problems to be managed based on the problem list. Finally, after setting the identified problems as the purpose of intervention through the hypothesis testing, therapist could do some intervention after making a plan to solve these problems, and find out the outcomes using the ICF evaluation display. This report illustrates how to apply the process based on ICF concept into physical therapy practice. Making a decision for the most efficient intervention requires that therapists use the clinical reasoning process based on ICF concept.

• Nuclear Engineering and Technology
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• 제50권2호
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• pp.229-236
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• 2018

Accident-tolerant fuels (ATFs) are currently of high interest to researchers in the nuclear industry and in governmental and international organizations. One widely studied accident-tolerant fuel concept is multilayer cladding (also known as coated cladding). This concept is based on a traditional Zr-based alloy (Zircaloy-4, M5, E110, ZIRLO etc.) serving as a substrate. Different protective materials are applied to the substrate surface by various techniques, thus enhancing the accident tolerance of the fuel. This study focuses on the results of testing of Zircaloy-4 coated with pure chromium metal using the cold spray (CS) technique. In comparison with other deposition methods, e.g., Physical vapor deposition (PVD), laser coating, or Chemical vapor deposition techniques (CVD), the CS technique is more cost efficient due to lower energy consumption and high deposition rates, making it more suitable for industry-scale production. The Cr-coated samples were tested at different conditions ($500^{\circ}C$ steam, $1200^{\circ}C$ steam, and Pressurized water reactor (PWR) pressurization test) and were precharacterized and postcharacterized by various techniques, such as scanning electron microscopy, Energy-dispersive X-ray spectroscopy (EDX), or nanoindentation; results are discussed. Results of the steady-state fuel performance simulations using the Bison code predicted the concept's feasibility. It is concluded that CS Cr coating has high potential benefits but requires further optimization and out-of-pile and in-pile testing.

• 한국정보처리학회논문지
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• 제6권6호
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• pp.1598-1608
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• 1999

ATM 망의 성능시험은 다양한 성능 인자를 측정하고 이를 분석함으로써 이를 분석함으로써 수행 가능한 망의 최대 수율, 즉 망의 성능을 평가함으로써 수행된다. 그러나, 지금까지 ATM 망에 대한 성능시험 방법 및 체계의 부재로 같은 시험 대상물에 대해서도 시험수행자에 따라 성능 측정의 결과가 크게 좌우되었다. 본 논문에서는 ATM 망을 대상으로 수행되는 성능 시험의 개념을 셀 레벨 및 프레임 레벨로 나누어 설명하며, 각각에 대해 성능 파라미터 및 성능 측정 방법론을 정의하고 성능 측정을 위한 시험 환경과 성능 평가시의 고려 사항을 기술함으로써 ATM 성능 시험의 전반적인 프레임워크를 제안한다.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제5권11호
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• pp.549-554
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• 2016

컨셉넷은 일반상식을 노드(개념)와 에지(관계)로 표현해 놓은 그래프 형태의 지식 베이스이다. 완전한 지식 베이스를 구축하는 것은 매우 어려운 문제이기 때문에 지식 베이스는 미완결된 형태의 데이터를 담고 있는 경우가 많다. 불완전한 지식을 담고 있는 지식 베이스로부터의 추론 결과는 신뢰하기 어렵기 때문에 지식의 완결성을 높이기 위한 방법이 필요하다. 본 논문에서는 신경 텐서망을 이용하여 컨셉넷의 지식 미완결성 문제를 완화해 보고자 한다. 컨셉넷에서 추출한 사실주장(assertion)을 이용하여 신경 텐서망을 학습시킨다. 학습된 신경 텐서망은 두 개의 개념 정보를 입력으로 받고, 그 두 개념이 특정 관계로 연결될 수 있는지를 나타내는 점수값을 출력한다. 이와 같이 신경 텐서망은 노드들의 연결 차수(degree)를 높여, 컨셉넷의 완결성을 증대시킬 수 있다. 본 연구에서 학습시킨 신경 텐서망은 평가데이터에 대해서 약 87.7%의 정확도를 보였다. 또한 컨셉넷에 연결이 없는 노드 쌍에 대하여 85.01%의 정확도로 새로운 관계를 예측할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.735-737
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• 2002

A current transformer for measuring current in high power testing laboratory is exactly proportional to the current including D.C component due to electrical transient. But, current transformer isn't designed to consider D.C component, therefore when data acquisition system measure that current. the error is increased because of saturation of core. This paper describe the concept of transient factor and how to design the current transformer.

• Journal of the Korean Statistical Society
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• 제35권2호
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• pp.167-177
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• 2006

An important role of statistical analysis in science is interpreting observed data as evidence, that is 'what do the data say?'. Although standard statistical methods (hypothesis testing, estimation, confidence intervals) are routinely used for this purpose, the theory behind those methods contains no defined concept of evidence and no answer to the basic question 'when is it correct to say that a given body of data represent evidence supporting one statistical hypothesis against another?' (Royall, 1997). In this article, we use likelihood ratios to measure evidence provided by record values in favor of a hypothesis and against an alternative. This hypothesis is concerned on mean of an exponential model and prediction of future record values.

• 비파괴검사학회지
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• 제30권6호
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• pp.527-538
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• 2010

This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified.

• 비파괴검사학회지
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• 제4권2호
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• pp.20-29
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• 1985

There are two basic concepts in industrial radiographic examination; one is a radio-graphic sensitivity, and the other is a acceptance criteria. The comparison of these main points are studied for KS Standard and ASME Boiler and Pressure Vessel Code. From the results of the experiment, higher radiographic sensitivity is required in KS Standard when the thickness of material to be examined is less than 20mm in single wall technique. The acceptance criteria for linear type indications are described on same concept in two standards, whereas the acceptance criteria for rounded indications of KS Standard which mainly depends upon the object thickness are more severe than those of ASME BPV Code.