• 비파괴검사학회지
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• 제22권6호
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• pp.627-636
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• 2002

Identification and sizing of surface breaking vertical cracks using angle beam ultrasonic testing in practical situation quite often become very difficult tasks due to the presence of non-relevant signals caused by geometric reflectors. The present work introduces effective and systematic approaches to take care of such a difficulty by use oi angle beam ultrasonic testing models that can predict the expected signals from various targets very accurately. Specifically, the model-based TIFD (Technique for Identification of Flaw signals using Deconvolution) is Proposed for the identification of the crack tip signals from the non-relevant geometric reflection signals. In addition, the model-based Size-Amplitude Curve is introduced for the reliable sizing of surface breaking vertical cracks.

• Smart Structures and Systems
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• 제32권6호
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• pp.371-382
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• 2023

Box girder bridges are now widely used in bridge construction, and it is necessary to perform load rating regularly to evaluate the load capacity of box girder bridges. Load testing is a common measure for load rating. However, the bridge must be loaded by many trucks under different loading conditions, which is time-consuming and laborious. To solve this problem, this paper proposes a load rating method for box girder bridges based on rapid moving loads testing. The method includes three steps. First, the quasi-influence factors of the bridge are obtained by crossing the bridge with rapidly moving loads, and the structural modal parameters are simultaneously obtained from the dynamic data to supplement. Second, an objective function is constructed, consisting of the quasi-influence factors at several measurement points and structural modal parameters. The finite element model for load rating is then updated based on the Rosenbrock method. Third, on this basis, a load rating method is proposed using the updated model. The load rating method proposed in this paper can considerably reduce the time duration of traditional static load testing and effectively utilize the dynamic and static properties of box girder bridges to obtain an accurate finite element model. The load capacity obtained based on the updated model can avoid the inconsistency of the evaluation results for the different structural members using the adjustment factors specified in codes.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2006년도 PROCEEDINGS OF JOINT CONFERENCEOF KDISS AND KDAS
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• pp.327-333
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• 2006

In this paper, we consider the Bayesian hypotheses testing for independence in bivariate exponential model. In Bayesian testing problem, we use the noninformative priors for parameters which are improper and are defined only up to arbitrary constants. And we use the recently proposed hypotheses testing criterion called the fractional Bayes factor. Also we give some numerical results to illustrate our results.

• 한국시뮬레이션학회논문지
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• 제27권1호
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• pp.25-32
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• 2018

본 논문은 모델 기반 내장형 소프트웨어의 자동 생성 코드에 대한 효율적인 신뢰성 시험 절차와 구체화된 동적 시험 방안에 대해서 제시하고 있다. 모델 정적/동적 시험 각각을 코드 정적/동적 시험 전에 수행함으로서 코드 신뢰성 시험 수행의 이점이 있음을 기술하였다. 또한, 모델과 코드의 신뢰성 시험 상관관계를 모델의 경우 Model Advisor와 Verification and Validation tool, 코드의 경우 Polyspace와 LDRA를 이용하여 살펴보고 제시한 절차대로 수행한 신뢰성 시험의 결과를 보여주고 있다.

• 분석과 대안
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• 제5권1호
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• pp.3-24
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• 2021

This paper introduces a multilevel item-response-theory (IRT) model as a unifying model for hypothesis testing using legislative voting data. This paper shows that a probit or logit model is a special type of multilevel IRT model. In particular, it is demonstrated that, when a probit or logit model is applied to multiple votes, it makes unrealistic assumptions and produces incorrect coefficient estimates. The advantages of a multilevel IRT model over a probit or logit model are illustrated with a Monte Carlo experiment and an example from the U.S. House. Finally, this paper provides a practical guide to fitting this model to legislative voting data.

• 한국융합학회논문지
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• 제7권6호
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• pp.35-41
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• 2016

소프트웨어의 중요성이 높아지면서 소프트웨어 품질평가에 대한 관심이 높아지고 있다. 본 연구에서는 소프트웨어 품질 평가를 위한 국제 표준 문서를 비교 분석하고 테스트 데이터 분석을 통한 평가 방안을 제시한다. 국제표준 ISO/IEC 9126-2의 평가 모델과 ISO/IEC 25023의 평가 모델에 대한 차이점을 비교했다. ISO/IEC 25023의 평가모델인 8가지 품질 특성, 즉 기능성, 신뢰성, 사용성, 유지보수성, 이식성, 효율성, 상호운영성, 보안성적인 측면에서 평가 메트릭을 제시했다. 실제 테스트를 통해 얻어진 331개 자료를 분석해서 테스트 데이터의 발견된 오류 특징을 파악했다. 또한 결함 자료를 분석하고 차이점을 파악했다. 테스트데이터가 남녀에 따라서 시험 일수나 발견하는 품질 특성별 오류의 수에는 차이가 있음을 증명하고 시험일수를 기능성, 사용성, 성별을 가지고 예측했으며, 제품의 종류에 따라서도 오류수에 차이가 있음을 증명했다.

• Communications for Statistical Applications and Methods
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• 제23권4호
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• pp.269-285
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• 2016

In this paper, a simple step-stress accelerated life test (ALT) under progressive type-II censoring is considered. Progressive type-II censoring and accelerated life testing are provided to decrease the lifetime of testing and lower test expenses. The cumulative exposure model is assumed when the lifetime of test units follows an extension of the exponential distribution. Maximum likelihood estimates (MLEs) and Bayes estimates (BEs) of the model parameters are also obtained. In addition, a real dataset is analyzed to illustrate the proposed procedures. Approximate, bootstrap and credible confidence intervals (CIs) of the estimators are then derived. Finally, the accuracy of the MLEs and BEs for the model parameters is investigated through simulation studies.

• 정보학연구
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• 제10권4호
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• pp.85-93
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• 2007

RFID applied in many area. I think that RFID enlarge for our life more and more. The application technology of RFID change the Mobile RFID using mobile phone and PDF etc. I think, Mobile RFID enlarge application technology gradually. In this paper, we propose the quality measurement metrics for mobile RFID middleware. I propose the quality testing model for interoperability and security of mobile RFID middleware. We examine the international standard for mobile RFID and software testing. In this paper, I proposed the evaluation model of mobile RFID middleware on the basis of international standard ISO/IEC 9126-2 and ISO/IEC 25000 series.

• 제어로봇시스템학회논문지
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• 제13권12호
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• pp.1179-1185
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• 2007

This paper presents a new approach to automotive embedded systems development and validation. Recently automotive embedded systems become even more complex and the product life cycle is getting reduced. To overcome these problems AUTOSAR, a standardized software platform and component based approach, was introduced. Model-based approach has been widely applied in the development of embedded systems and has strong benefits such as early validation and automated testing. In this paper cooperative development and validation of AUTOSAR and model-based approach are introduced and automated testing techniques are proposed. With the proposed techniques we can improve complexity management through increased reuse and exchangeability of software module and automated testing is realized.

• Smart Structures and Systems
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• 제4권6호
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• pp.809-828
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• 2008

Real-time hybrid testing is an attractive method to evaluate the response of structures under earthquake loads. The method is a variation of the pseudodynamic testing technique in which the experiment is executed in real time, thus allowing investigation of structural systems with time-dependent components. Real-time hybrid testing is challenging because it requires performance of all calculations, application of displacements, and acquisition of measured forces, within a very small increment of time. Furthermore, unless appropriate compensation for time delays and actuator time lag is implemented, stability problems are likely to occur during the experiment. This paper presents an approach for real-time hybrid testing in which time delay/lag compensation is implemented using model-based response prediction. The efficacy of the proposed strategy is verified by conducting substructure real-time hybrid testing of a steel frame under earthquake loads. For the initial set of experiments, a specimen with linear-elastic behavior is used. Experimental results agree well with the analytical solution and show that the proposed approach and testing system are capable of achieving a time-scale expansion factor of one (i.e., real time). Additionally, the proposed method allows accurate testing of structures with larger frequencies than when using conventional time delay compensation methods, thus extending the capabilities of the real-time hybrid testing technique. The method is then used to test a structure with a rate-dependent energy dissipation device, a magnetorheological damper. Results show good agreement with the predicted responses, demonstrating the effectiveness of the method to test rate-dependent components.