• Journal of Korea Water Resources Association
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• v.45 no.3
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• pp.275-290
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• 2012

In this study, we have developed an optimal time distribution model through extraction of peaks over threshold (POT) series. The median values for annual maximum rainfall dataset, which are obtained from the magnetic recording (MMR) and the automatic weather system(AWS) data at Seoul meteorological observatory, were used as the POT criteria. We also suggested the improved methodology for the time distribution of extreme rainfall compared to Huff method, which is widely used for time distributions of design rainfall. The Huff method did not consider changing in the shape of time distribution for each rainfall durations and rainfall criteria as total amount of rainfall for each rainfall events. This study have suggested an extracting methodology for rainfall events in each quartile based on interquartile range (IQR) matrix and selection for the mode quartile storm to determine the ranking cosidering weighting factors on minutely observation data. Finally, the optimal time distribution model in each rainfall duration was derived considering both data size and characteristics of distribution using kernel density function in extracted dimensionless unit rainfall hyetograph.

• The Korean Journal of Applied Statistics
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• v.23 no.6
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• pp.1057-1065
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• 2010

In this paper we discuss some cautionary notes in using the Pearson chi-squared test statistic for the goodness-of-fit of the ordinal response model. If a model includes continuous type explanatory variables, the resulting table from the t of a model is not a regular one in the sense that the cell boundaries are not fixed but randomly determined by some other criteria. The chi-squared statistic from this kind of table does not have a limiting chi-square distribution in general and we need to be very cautious of the use of a chi-squared type goodness-of-t test. We also study the limiting distribution of the chi-squared type statistic for testing the goodness-of-t of cumulative logit models with ordinal responses. The regularity conditions necessary to the limiting distribution will be reformulated in the framework of the cumulative logit model by modifying those of Moore and Spruill (1975). Due to the complex limiting distribution, a parametric bootstrap testing procedure is a good alternative and we explained the suggested method through a practical example of an ordinal response dataset.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.870-875
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• 2013

After introducing diagnosis equipment power failure prevention activities for distribution system have become more active. To do facility diagnosis and maintenance work more efficiently we need to evaluate reliability for the system and should determine the priority line with appropriate criteria. Thus, to calculate risk factor for the power distribution line that are composed of many component facilities its historical failure events for the last 5 years are collected and analysed. The failure statics show that more than 60% of various failures are related to environment factors randomly and about 20% of the failures are refer to the aging. As a strategic evaluation system reflecting these environmental influence is needed, a system on the basis of the probabilistic approach related statical variables in terms of failure rate and failure probability of electrical components is proposed. The figures for the evaluation are derived from the field failure DB. With adopting Bayesian rule we can calculate easily about conditional probability query. The proposed evaluation system is demonstrated with model system and the calculated indices representing the properties of the model line are discussed.

• The Journal of Industrial Distribution & Business
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• v.4 no.2
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• pp.41-49
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• 2013

Purpose - Currently, the distribution environment has been changing rapidly because of the advent of super-supermarkets (SSM),which adopt the "price break" and "lowest price" strategies. Specifically, a diversification of the distribution environment allowed customers to reasonably decide where to shop. With a broadened range of criteria governing the choice of a store, determining changes in the distribution environment should be based on customer satisfaction surrounding the service levels of SSMs. This study examines the effects of service quality and product quality of SSMs on customer satisfaction levels, and analyzes whether these factors affect customers' revisit intention directly. Research design and methodology - A survey method was used and 127 SSM customers responded to the questionnaires that were developed to measure service quality, product quality, customer satisfaction, and store revisit intention. A multi-regression analysis was used to test the hypotheses. Results - Except hypothesis 2, the other seven hypotheses were supported. Hypothesis 2 suggested a positive relationship between product factors and customer satisfaction. Conclusions - This study found a systematic effect of service factors and product factors on customer satisfaction and word-of-mouth, and consequently on store revisit intention.

• Journal of Communications and Networks
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• v.7 no.4
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• pp.438-449
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• 2005

In this paper, we describes the information-theoretic approaches to sensor selection and sensor placement in sensor net­works for target localization and tracking. We have developed a sensor selection heuristic to activate the most informative candidate sensor for collaborative target localization and tracking. The fusion of the observation by the selected sensor with the prior target location distribution yields nearly the greatest reduction of the entropy of the expected posterior target location distribution. Our sensor selection heuristic is computationally less complex and thus more suitable to sensor networks with moderate computing power than the mutual information sensor selection criteria. We have also developed a method to compute the posterior target location distribution with the minimum entropy that could be achieved by the fusion of observations of the sensor network with a given deployment geometry. We have found that the covariance matrix of the posterior target location distribution with the minimum entropy is consistent with the Cramer-Rao lower bound (CRB) of the target location estimate. Using the minimum entropy of the posterior target location distribution, we have characterized the effect of the sensor placement geometry on the localization accuracy.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.51-57
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• 2013

Recently, improvement of materials and technologies for the manufacturing of gas pipe has it possible to reduce the buried depth. Compared to the criteria from advanced countries, Korea has conservative criteria for the buried depth of pipeline(about 50cm deeper). Therefore, this study investigated the effect of various buried depth(0.8m, 1.0m, 1.2m) on the stress and strain distribution of gas pipe. Numerical analysis and field tests were carried out with API 5L steel gas pipes. From the results, it can be suggested that the change of buried depth would not significantly affect the stress and strain distribution of gas pipe.

• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.143-153
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• 2018

Background: The determination of the amount of radionuclides and internal dose for the worker who may have intake of radionuclides results in a variation due to uncertainty of measurement data and ingestion information. As a result of this, it is possible that for the same internal exposure scenario assessors could make considerably different estimation of internal dose. In order to reduce this difference, internal exposure scenarios for nuclear facilities were developed, and intercomparison were made to determine the harmonization of dose assessment results among the assessors. Materials and Methods: Seven cases on internal exposures incidents that have occurred or may occur were prepared by referring to the intercomparison excercise scenario that NRC and IAEA have carried out. Based on this, 16 nuclear facilities concerned with internal exposure in Korea were asked to evaluate the scenarios. Each result was statistically determined according to the harmonization discrimination criteria developed by IDEAS/IAEA. Results and Discussion: The results were evaluated as having no outliers in all 7 cases. However, the distribution of the results was spread by various causes. They can be divided into two wide categories. The first one is the distribution of the results according to the assumption of the intake factors and the evaluation factors. The second one is distribution due to misapplication of calculation method and factors related to internal exposure. Conclusion: In order to satisfy the harmonization criteria and accuracy of the internal exposure dose evaluation, it is necessary that exact guidelines should be set on low dose, and various intercomparison cases also be needed including high dose exposure as well as the specialized education. The aim of the blind test is to make harmonization evaluation, but it will also contribute to securing the expertise and high quality of dose evaluation data through the discussion among the participants.

• Korean Journal of Plant Taxonomy
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• v.40 no.4
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• pp.202-207
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• 2010

The most useful criteria and selection procedures of biological indicators have been developed in Korea because they have taken into account local and national concerns on biological responses against climate change. On the basis of these criteria and selection procedures, 100 climate-sensitive biological indicator species were selected to predict biodiversity distribution shift by climate change and manage biological resources integratedly at the national level. It is expected that selection and monitoring of biological indicators by climate change will provide significant information to prepare protective strategies of vulnerable species against climate change and adaptive policies under the changing environment in Korea. In this paper, we have reviewed what kinds of criteria were considered in selecting bioindicators to assess responses of biological organisms against climate change. Definition and selection steps of bioindicators were proposed, and the 100 species of climate- sensitive biological indicators were selected out of 33,253 taxa reported in Korea.

• Journal of the Korean association of regional geographers
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• v.9 no.4
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• pp.546-558
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• 2003

Social justice has been an interest of whole geographers for almost four decades. The conception of social justice includes fairness and equity in the distribution of a wide range of attributes. The purpose of this study is to understand social justice in geography of welfare. The theories of social justice are needed to describe relationship between social justice and geography of welfare. The evaluation of spatial variations in welfare is closely associated with social justice. Equality, equity, efficiency, and fairness are the reasonable criteria to apply to the evaluation of distributions of welfare, relating to distributive(or territorial) justice. However, there are complications in the spatial application of welfare evaluation criteria, including access across space, boundary crossing and ecological fallacy.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.843-851
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• 2020

This study focuses on identifying and prioritizing the broader performance measures for the service supply chains by taking the case of Majan Electricity Company, Sohar, in the Sultanate of Oman. For an examination of the uniformity of ultimate objectives and the priorities therein, two strata of respondents with a total of fourteen respondents were approached for their valuable insights. Suitable structured instruments were personally administered to elicit the insightful and worthy responses. The two multi-criteria decision-making techniques, namely, the Fuzzy Analytical Hierarchy Process and the Best-Worst Method were used to reach a meaningful prioritization of the identified and refined broader performance measurement dimensions. The results show that there exists a minor gap between the two respondents' groups in terms of their prioritizations. The major finding points to the difference in terms of the topmost priorities as revealed by the two set of respondents. For one group of respondents, the customer satisfaction matters the most, whereas for the other group, it is the overall profitability that matters the most. This gap against the utopian state assists in concluding that there is a requirement to reorient the employees so as to have a shared and common understanding of the organizational priorities.