• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1017-1028
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• 2011

When it is not easy to decide the credit scoring for some loan applicants, credit evaluation is postponded and reserve to ask a specialist for further evaluation of undecided applicants. This undecided inference is one of problems that happen to most statistical models including the biostatistics and sportal statistics as well as credit evaluation area. In this work, the undecided inference is regarded as a missing data mechanism under the assumption of MNAR, and use the bivariate probit model which is one of sample selection models. Two undecided inference methods are proposed: one is to make use of characteristic variables to represent the state for decided applicants, and the other is that more accurate and additional informations are collected and apply these new variables. With an illustrated example, misclassification error rates for undecided and overall applicants are obtainded and compared according to various characteristic variables, undecided intervals, and thresholds. It is found that misclassification error rates could be reduced when the undecided interval is increased and more accurate information is put to model, since more accurate situation of decided applications are reflected in the bivariate probit model.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.10-15
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• 2007

For the introduction of the electricity of the special design and supervision system to Protect the faulty-workmanship of the electricity equipment and to reserve the electricity safety, last 1995 "Electricity Technology Management Act" were carried out enactment. March 2002, we introduced the pre-Qualification system that is selected the competent company about the electricity design and supervision service over so much capacity which is ordered by the Public institution such as the nation, local autonomous entity, government investment institute and so on. December 2005, the electricity equipment over so much capacity was taken the housing construction plan's approval by the housing act in case, the municipal or district governor with the authority to approve who selected the electricity supervision company according to the pre-Qualification system. Due to the introduction of the system, we could expect the rights and interests increase of the consumer by eradicating dumping of the close relationship between supervision company and the builder, reduction and concurrent position of the supervisor, according to confirm the quality of the electricity equipment and electricity safety. In spite of introducing of the system, the problems occured as reducing the electricity designer's task range compared with different field, modifing the supervisor's rank system rationally, because of researching about the electricity design and supervision technique lacks. Also, KEEA(Korea Electric Engineers Association) manage the caller of the electricity design and supervisor(company or people), but the problems occured as opening to the public about the curler management, introducing automatic bidding system and We need the solution plan about this. Consequently, we consider the present situation of the domestic and outside and problem about the electricity design and supervision system in this paper, try to present rational operation plan through this.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.526-534
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• 2014

In this paper, for the WiMedia Distributed Medium Access Control (D-MAC) protocol based on UWB. performance degradation due to the Distributed Reservation Protocol (DRP) conflict problem caused by devices' mobility is analyzed. And a DRP relay protocol and a DRP conflict resolution (CR) are proposed to overcome the performance degradation at DRP conflicts. In order to give the loser device at DRP conflicts a chance to maintain resources, the proposed DRP relay protocol executed at each device helps the loser device reserve an indirect link maintaining the required resources via a relay node. Simulation results considering the mobile environment have indicated that the DRP relay combined with the CR prevent the throughput decrease even though mobility of devices increases.

• Resources Recycling
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• v.29 no.2
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• pp.48-54
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• 2020

Korea, one of the manufacturing-oriented countries, consumes a large amount of metals in various industrial areas, but should depend on import of most of the metals from foreign countries. Also, global metal consumption amounts are increasing in relation to those of the world's reserve and production. Some metals are limitedly produced from only several centuries, which might lead to instability of the future supply of those metals. In addition, when such metals are hazardous, those may result in various environmental troubles with contamination. To resolve those issues, the recovery and the recycling of hazardous but valuable metals in industrial waste are desirable. However, there are overwhelming numbers of the metal types, waste generators, and amounts of wastes containing the metals, so it can be troublesome even to implement a preliminary status analysis to screen proper metals, wastes with the metals, and waste producers. Therefore, this study introduces the valuable metals for Korean industry, announced by public institutions, Also, a flow chart is suggested to facilitate a preliminary status analysis, using the domestic PRTR (Pollutant Release and Transfer Register) database, to screen proper waste producers containing some of hazardous but valuable metals such as nickel, cobalt, and manganese.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.8
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• pp.528-534
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• 2014

Thermal batteries are primary reserve batteries that use inorganic salt as electrolytes which are inactive at room temperature. The two principal heat sources that have been used in thermal batteries are heat paper and heat pellets. As soon as the heat paper, which is ignited by the initiator, in turn ignites the heat pellets, all the solid electrolytes are melted into excellent ionic conductors. However, the high combustion temperature by heat papers in thermal batteries causes thermal decomposition at the cathode, eventually leading to a thermal runaway. In this paper, we have attempted to prepare $Zr/BaCrO_4$ heat papers coated with KCl molten salt. We have also investigated the effect of a molten salt coating on the heat papers through the thermal characteristics such as calorimetric value, combustion temperature and burning rate. The calorimetric value and combustion temperature of heat papers were reduced with an increase in the molten salt coating. As a result, the molten salt coating on heat papers greatly reduced risk of a thermal runaway and improved the stability of thermal batteries.

• Genomics & Informatics
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• v.8 no.3
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• pp.150-158
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• 2010

Genome-wise association studies (GWASs) have become popular approaches to identify genetic variants associated with human biological traits. In this study, we applied Structural Equation Models (SEMs) in order to model complex relationships between genetic networks and traits as risk factors. SEMs allow us to achieve a better understanding of biological mechanisms through identifying greater numbers of genes and pathways that are associated with a set of traits and the relationship among them. For efficient SEM analysis for GWASs, we developed a procedure, comprised of four stages. In the first stage, we conducted single-SNP analysis using regression models, where age, sex, and recruited area were included as adjusting covariates. In the second stage, Fisher's combination test was conducted for each gene to detect significant genes using p-values obtained from the single-SNP analysis. In the third stage, Fisher's exact test was adopted to determine which biological pathways were enriched with significant SNPs. Finally, based on a pathway that was associated with the four traits in common, a SEM was fit to model a causal relationship among the genetic factors and traits. We applied our SEM model to GWAS data with four central obesity related traits: suprailiac and subscapular measures for upper body fat, BMI, and hypertension. Study subjects were collected from two Korean cohort regions. After quality control, 327,872 SNPs for 8842 individuals were included in the analysis. After comparing two SEMs, we concluded that suprailiac and subscapular measures may indirectly affect hypertension susceptibility by influencing BMI. In conclusion, our analysis demonstrates that SEMs provide a better understanding of biological mechanisms by identifying greater numbers of genes and pathways.

• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.381-395
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• 2011

Present work aims to establish an integrated management system of environmental data base for nine typical wind holes or air holes in Korea. It basically deals with definition, geographical distribution, morphological pattern, physical characteristics and anthropogenic environments of wind hole to propose systematic preservation strategy of their periglacial landscape and flora, which are known to be sensitive to global warming. Wind hole, in which cool air blows out during the summer, but mild air comes out during the winter from a cave or hole, is frequently found on northwest- and north-facing slopes on the terminal point of steep talus, block field, and block stream, and can be categorized into three types, i.e., talus, cave and sink types. Environmental characteristics of nine wind holes are analyzed on the basis of their geology, landform, climate, soil, hydrology, vegetation, road, footpath, land-use, and management system, and relevant DB are prepared. Wind hole areas with unique landscape and ecological values need to be designated as a nature reserve, and zoning of core, buffer, and transitional zones are required for the multi-dimensional preservation of periglacial landscape and ecosystem. Phytogeographical values of glacial relict plants, including mountain cranberry(Vaccinium vitis-idaea) at its global southernmost limit at Bangnaeri wind hole, Hongchon County, Gangwon Province of Korea are discussed in detail as a floristic refugia in connection with climate change during the Pleistocene Epoch and potential in-situ and ex-situ preservation sites in the future.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.6
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• pp.263-267
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• 2007

We have previously demonstrated that the level of leukocytes and neutrophils significantly increased immediately and 30 min after exercise. Interleukin-8 (IL-8) is an inflammatory cytokine that acts as a chemokine on neutrophils. In the present study, we evaluated the correlation between the number of neutrophils and leukocytes, and between the number of neutrophils and plasma IL-8 level. Long-distance trained runners (TRs, n = 10) and untrained sedentary control subjects (SEDs, n = 10) ran for one hour at 70% of heart rate reserve. In the TR, the number of neutrophils correlated significantly with the number of leukocytes in the blood. However, there was no correlation between the number of neutrophils and the plasma IL-8 concentration in both groups. Expressions of IL-8 protein and mRNA were markedly higher in the TRs as compared to the SEDs at three time intervals (pre-exercise, immediately after exercise, and post exercise). In conclusion, our results show that 1) the neutrophil level was dependent on the level of leukocytes 2) there was no correlation between the neutrophils count and plasma IL-8 concentration and 3) a higher plasma IL-8 level in athletes may be a unique characteristic of intensive training.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.179-185
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• 2016

This study verifies whether speculative trading in commodity markets acted as the primary cause of the increase in commodity prices after the global financial crisis using the Structural Vector Autoregressive (SVAR) model. The effects of speculative trading on commodity prices increased by a factor of 3 to 6 after the crisis compared to those before the crisis. Although the demand related variables, such as industrial production, affected commodity prices significantly before the crisis, their effects decreased after the crisis. Consequently, the rebound of commodity prices after the crisis was mainly caused by the increase in speculative money, fortified by the expansion of the global liquidity supply. The global liquidity may well increase in the future, because the U.S. Federal Reserve Board is likely to continue to increase its interest rate. This study claims that when global liquidity shrinks as a result of a change in the Fed's monetary policy stance, speculative trading will slow down, leading to a decline in commodity prices.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.139-146
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• 2003

The objective of the presented study is to develop an efficient procedure of proof load testing for existing bridges. By analytical methods, some of these bridges are not adequate to carry normal highway traffic. However, the actual load carrying capacity is often much higher than what can be determined by conventional analysis. Proof load testing can reveal the hidden strength reserve and thus verify the adequacy of the tested bridge. Proof load level required for meaningful tests should be sufficiently higher than legal load. In the state of Michigan, the legal 11-axle truck can weigh up to 685 kN. In this study, a combination of two military tanks and two Michigan 11-axle trucks was used. The proof loads were gradually increased to ensure the safety of the test. After each move, measurements were taken. For the considered bridge, stress levels were rather low compared to pre-test analysis results. This is due to incorrect material strength, structural contribution of nonstructural components such as parapets and railings, and partially fixed supports.