• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.155-157
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• 2005

The Electrical Test Bed(ETB) integrates the test environment, required for acceptance tests of system level, prior to FM testing. The ETB will be used for the validation of system-level functions and interface between each subsystem. The FTB supports early functional and limited performance checkout of electrical subsystems. Therefore, it provides the environment for the verification of the Flight Software including AOCS, EPS, and TC&R simulators. These ETB will be composed of engineering version of spacecraft BUS, which are laid on the laboratory table.

• International Journal of Reliability and Applications
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• v.17 no.1
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• pp.85-105
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• 2016

In this paper accelerated life testing is incorporated in quality control technique of acceptance sampling plan to induce early failures in high reliability products.Stress under accelerated condition can be applied in constant-stress, step-stress and progressive-stress or combination of such loadings. A ramp-stress results when stress is increased linearly (from zero) with time. In this paper optimum failure-censored ramp-stress accelerated life test sampling plan for log-logistic distribution has been formulated with cost considerations. The log-logistic distribution has been found appropriate for insulating materials. The optimal plans consist in finding optimum sample size, sample proportion allocated to each stress, and stress rate factor such that producer's and consumer's interests are safeguarded. Variance optimality criterion is used when expected cost per lot is not taken into consideration, and bilevel programming approach is used in cost optimization problems. The methods developed have been illustrated using some numerical examples, and sensitivity analyses carried out in the context of ramp-stress ALTSP based on variable SSP for proportion nonconforming.

• IE interfaces
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• v.11 no.1
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• pp.67-74
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• 1998

This study is to develop a vehicle scheduling system for the efficient delivery of goods to places of business. For gathering data and testing the system developed, we have chosen a company which is located in Taegu city and has more than 700 delivery points over Taegu city and Kyungbuk province. We consider multiple vehicle types, travel time restrictions on vehicles, vehicle acceptance restrictions at delivery points, and other operational restrictions. We divide the whole delivery points into 44 regions and generate a region-based shortest path tree. Based on the shortest path tree, we perform vehicle assignment sequentially for each vehicle used. Then vehicle routings are determined. We have implemented the whole procedure on computer system. The system developed is flexible enough to be applicable to other companies by just changing the standard data.

• Korean Management Science Review
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• v.13 no.3
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• pp.115-128
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• 1996

System usage, the utilization of information technology(IT) by individuals, groups or organizations, is a core variable in IS research. Indeed, there is widespread agreement among researchers that system usage is the primary variable through which IT affects white collar performance because it is a requisite, albeit insufficient, for deriving the benefits of IT. Furthermore, system usage has a notable practical value for managers interested in evaluating the impact of IT. Despite the number of studies of targeted at explaining system usage, there are more areas which required for the verification of system usage. The purpose of this paper is to address, using the Technological Acceptance Model (TAM), the usage pattern of AHP toward the various task in group decision (GD). The result showed that, for the all of the task types, perceived usage (PU) has more effect than perceived ease-of-use(PEU) on the AHP usage. However, more researches are required to generalize the result of this study.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.1
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• pp.19-24
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• 2009

We propose some properties for fuzzy binomial proportion test by agreement index. First we define fuzzy probability space and fuzzy type I error and type II error for the fuzzy probability of the two type errors. Also, we show that a fuzzy power function of performance for a fuzzy hypothesis test and drawing conclusions from the test.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.6
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• pp.592-596
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• 2014

We shall consider fuzzy hypotheses test for signed-rank Wilcoxon fuzzy test by fuzzy difference on rate of internal division. Fundamental to these discussion are fuzzy number data and Wilcoxon signed-rank fuzzy test of a fuzzy hypothesis $H_{f0}$ which is based upon a fuzzy statistics whose distribution does not depend upon the specified distribution or any parameters.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.2
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• pp.147-153
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• 2017

In order to demonstrate a target reliability with a specified confidence level, a new two-stage Bayesian Reliability Demonstration Test (RDT) plans that is known to be more effective than a corresponding single-stage one is proposed and developed by Bayesian framework with beta prior distribution for Weibull life time distribution. A numerical example is provided to illustrate the proposed RDT plans and compared with other non-Bayesian and Bayesian plans. Comparative results show that the proposed Bayesian two-stage plans have some merits in terms of required and expected testing time and probability of acceptance.

• Journal of the Korea Safety Management & Science
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• v.9 no.2
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• pp.123-134
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• 2007

This paper focuses on the in-house reliability assurance plan for the bulk materials of each company. The reliability assurance needs in essence a long time and high cost for testing the materials. In order to reduce the time and cost, accelerated life test is adopted. The bulk sampling technique was used for acceptance. Design parameters might be total sample size(segments and increments}, stress level and so on. We focus on deciding the sample size by minimizing the asymptotic variance of test statistics as well as satisfying the consumer's risk. In bulk sampling, we also induce the sample size by adapting the normal life time distribution model when the variable of the lognormal life time distribution is transformed and adapted to the model. In addition, the sample size for both the segments and increments can be induced by minimizing the asymptotic variance of test statistics of the segments and increments with consumer's risk met. We can assure the reliability of the mean life and B100p life time of the bulk materials by using the calculated minimum sample size.

• The Journal of Information Systems
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• v.15 no.4
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• pp.189-209
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• 2006

The progress of mobile internet technologies has changed user access to information. The mobile internet allows to obtain contents and services from wireless networks via mobile devices. The purpose of this study is th find out important factors that influence on the customer purchase intention by mobile internet environment. Base on TAM(Technology Acceptance Model) and the latest literature, a comprehensive set of constructs and hypotheses were compiled with a methodology for testing them. We suggested five factors that effect purchase intention in mobile internet environment: Enjoyment Ease of use, Usefulness, Mobility, Trust To validate the research model, we collected data from cellular phone user using an online survey. The results of this study are as follows. First enjoyment ease of un, usefulness, and mobility had positive effects on trust. Second, Usefulness, ease of use, and trust had positive effects on purchase intention to use mobile internet. Third, enjoyment and mobility did not have positive effects on purchase intention to use mobile internet. Based on these results, we suggest marketing strategies.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.963-970
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• 2018

The U.S. Nuclear Regulatory Commission, Regulatory Guide 1.20 needs to perform a comprehensive vibration assessment program for reactor internals during preoperational and startup testing for nuclear power plants and extended power uprate. Although the measurement program is one of the core programs, it is rarely carried out except for a first-of-a-kind or a unique design. This article describes measurement results of vibration and stress for the comprehensive vibration assessment program for an APR-1400 reactor internals. The measurement was performed at an upper guide structure during the pre-core hot functional test of Shin Kori unit 4 reactor internals because the Shin Kori unit 3 and 4 are the first construction project for the APR-1400, and the upper guide structure assembly was to design change compared with the valid prototype. We confirmed that all measured results are within the test acceptance criteria. It means that the structural integrity of the APR-1400 reactor internals was secured for the flow-induced vibration.