• Proceedings of the Korean Statistical Society Conference
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• 2003.05a
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• pp.137-142
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• 2003

We discuss why sample design by mathematical programming can be beneficial to practical surveys. We illustrate some developments of software for sample design using mathematical programming in several statistical organizations. Also, we present certain restrictions on the use of mathematical programming.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.69-72
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• 2003

The PCI Express spec introduces retry buffer in Data Link Layer For data integrity. But this buffer have some restrictions as buffer's usage. So we proposed effective management for retry buffer on PCI-Express interface. Proposed buffer management give increase performance and data integrity simultaneously.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.49-57
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• 2003

In this paper, we give some sufficient conditions for convergence of geometric mean for T-related fuzzy numbers where T is an Archimedean t-norm under some mild restrictions. These results generalize earlier results of Hong and Lee [Fuzzy Sets and Systems 116 (2000) 263-267].

• Communications for Statistical Applications and Methods
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• v.2 no.2
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• pp.129-134
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• 1995

The ordinary least square estimator of the disturbance variance in the pooled cross-sectional and time series regression model is shown to be asymptotically unbiased without any restrictions on the regressor matrix when the disturbances follow an equicorrelated error component models.

• Journal of the Korean Statistical Society
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• v.25 no.3
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• pp.381-391
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• 1996

In the analysis of contingency table with ordered categories, the relationship between odds for adjacent categories has received con-siderable interest. We consider likelihood ratio tests of independence against an order restriction on odds in 2 $\times$ k contingency tables.

• Communications for Statistical Applications and Methods
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• v.16 no.1
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• pp.137-141
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• 2009

We study on selecting the kernel weighting function in smoothing moment conditions for dependent processes. For hypothesis testing in Generalized Method of Moments or Generalized Empirical Likelihood context, we find that smoothing moment conditions by Bartlett kernel delivers smallest size distortions based on empirical Edgeworth expansions of the long-run variance estimator.

• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.863-879
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• 2019

In this paper we study the Myers' theorem for orientable Riemannian hypersurfaces under some restrictions on the mean curvature, the second-order mean curvature, or the divergence of the shape operator and give some estimates for the diameter of such hypersurfaces.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.25-31
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• 2014

Korean grammar checkers typically detect context-dependent errors by employing heuristic rules; these rules are formulated by language experts and consisted of lexical items. Such grammar checkers, unfortunately, show low recall which is detection ratio of errors in the document. In order to resolve this shortcoming, a new error-decision rule-generalization method that utilizes the existing KorLex thesaurus, the Korean version of Princeton WordNet, is proposed. The method extracts noun classes from KorLex and generalizes error-decision rules from them using the Tree Cut Model and information-theory-based MDL (minimum description length).

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.115-121
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• 2020

This study aims to investigate the effects of restrictions in economic activity on the spread of COVID-19 in the Philippines. This research employs daily time-series data of confirmed new COVID-19 cases, Apple mobility trends (i.e., use of public transport to destinations, volume of people driving, and amount of walking to destinations) and Google community mobility (i.e., visits to transit stations, visits to workplaces, and staying-at-home) indicators covering the period February 17 to September 11, 2020. The analysis starts by establishing the correlation pattern of new confirmed COVID-19 daily infections to each independent variable. The results show negative linear correlation of the number of new COVID-19 daily infections with less visit to transit station, increase stay-at-home, less use of public transport, and less amount of walking to destinations. Interestingly, the number of new COVID-19 daily infections indicates some form of positive linear correlation with visits to workplaces and volume of people driving. Moreover, employing robust least square regression via the method of MM-estimation, major findings reveal that across mobility measures, staying-at-home has the highest impact on reducing the spread of COVID-19, followed by visiting transit stations less, less use of public transport, less amount of walking, and less workplace visits.

• Journal of Korean Association for Spatial Structures
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• v.19 no.4
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• pp.85-94
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• 2019

Then 3D printing is used practically at construction sites, there is a serious lack of studies on the conflict with construction-related laws and expected operational problems. Accordingly, the purpose of this study is to present obstacles and directions for improvement in construction-related laws (Building Act, Construction Technology Promotion Act, Housing Act, Construction Machinery Management Act, etc.) for practical operation of 3D printing. The important results are as follows. Amending existing construction-related laws for 3D printing is irrational and inefficient in terms of structure and material. This study proposed a method of satisfying performance required by laws or standards based on the performance design method presented in existing laws and systems through structure and material performance certification procedure. In addition, inclusion of 3D printing equipment in the Construction Machinery Management Act results in various restrictions such as equipment inspection and certification of machine parts. As such restrictions can block vitalization of 3D printing, a long-term and step-wise approach was suggested.