• Journal of Power Electronics
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• v.13 no.4
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• pp.647-655
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• 2013

In this paper, an approach to reduce the common-mode voltage and to eliminate narrow pulse for implemented AC-DC matrix converters is presented. An improved space vector modulation (SVM) strategy is developed by replacing the zero space vectors with suitable pairs of active ones. Further, while considering the commutation time, the probability of narrow pulse in the conventional and proposed SVM methods are derived and compared. The advantages of the proposed scheme include: a 50% reduction in the peak value of the common-mode voltage; improved input and output performances; a reduction in the switching loss by a reduced number of switching commutations and a simplified implementation via software. Experimental results are presented to demonstrate the correctness of the theoretical analysis, as well as the feasibility of the proposed strategy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.23-25
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• 2005

Infrared bolometer sensor's variation is detected by voltage drop between reference resistor and bolometer resistor in this architecture. One of the serious problems in this architecture is that these resistors value has a process variation. So common-mode level could be different from expectation in room temperature. Different common-mode level could lead to wrong output at the end of readout circuit. We suggest useful method to solve this problem. Difference correction using capacitor has reduced CM level difference to 86% for 1 $M\Omega$. bolometer and reference resistor's 10% variation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.15 no.25
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• pp.23-31
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• 1992

This paper is concerned with an n jobs one machine Job shop scheduling problems in which all jobs have a common due date and unequal penalties occur when a job is completed before or after due date. The objective is to determine an optimal sequence and the corresponding common due date that yield the global minimum value of a penalty function Then a sequence that minimize the penalty function globally is a V-shaped sequence Using the idea of linear equations and a LGP(Linear Goal Programming), this paper shows that LGP and MAD(Mean Absolute Deviation) are equivalent problems. Therefore an efficient algorithm that is developed for MAD problem holds for LGP problem and vice-versa. A numerical example to account for the algorithm is provided.

• The Korean Journal of Emergency Medical Services
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• v.23 no.1
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• pp.71-85
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• 2019

Purpose: The purpose of this study was to provide basic data for developing strategic programs based on 119 emergency medical technicians leadership perception types. Methods: The subjects were thirty six 119 emergency medical technicians working for out-of hospital in Jeollanam-Do, Korea. Data were collected from July 20, 2017 to October 30, 2017. Q sample of 40 statements and P sample of 36 persons using PC QUANL software. Results: Three types of leadership styles were identified from the explanation (71.5% of the variables). The relationship oriented progressive type (the most common), the performance and value oriented type (the second most common), and the experience oriented filed participation type (the third most common). Conclusion: The fire department will need to develop and implemented leadership improvement programs based on the leadership types in order to meet the organization's goals.

• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.122-132
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• 2005

The importance of design value engineering in construction projects recently is rising, which deal about in reduction of cost and improvement of quality. Especially, From half of this year 2005, It is predicted that the value engineering is necessary to be carried out in the projects having project cost more than 10 billion won. In increasing importance of value engineering, we require a way by which we accomplish value engineering systemically and effectively though it is not common in domestic situation. So, this case study shows a way in carrying out value engineering effectively. As the way is to apply QFD(Quality Function Deployment) in pre-study work of design value engineering, this is expected to contribute as function analysis and reflect the requirement of users or owners.

• Journal of the Korean Society of Food Culture
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• v.30 no.1
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• pp.54-63
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• 2015

This study was conducted to examine the effects of local food value perception on purchasing and experience in consumers. ${\chi}^2$-test, ANOVA, and linear regression analysis were conducted. The findings are summarized as follows: The most common place for buying agricultural products was 'hypermarkets' (41.7%), and the most important factor for purchasing local food was 'local government's certification products' (23.7%). The most important value recognition item for local food was 'I think that local food is a high-quality agricultural products'. (3.74 points), followed by 'I think that local food have a value of respect for customers' (3.61 points) and 'I have a faith for the local food'. (3.61 points) in that order. The main tourism experience activity was 'food experience' (49.0%), and information source of local food experience tourism was 'mass media (TV, newspapers, etc.)' (37.3%). As age increased, experience of local food also increased. The most effectual value recognition item for purchasing local food was 'I think that local food have a value of respect for customers'. The most effectual value recognition item for increasing intake experience of local food was 'I think that the local food is high-quality agricultural products'.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.3
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• pp.366-377
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• 2013

We examined the nutritive value of common grass species in the semi-arid rangelands of Borana in southern Ethiopia using local experience based herbage preference (LEBHP) perception and laboratory techniques. Local pastoralists in the study area were asked to identify common grass species and rank them according to the species' preferences and palatability to cattle. The pastoralists listed a total of 15 common grass species which were then sampled during the main rain and cold dry seasons and analyzed for crude protein (CP), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF) and ash content to verify pastoralists' claim regarding the quality of individual species. The relative feed value (RFV) and dry matter digestibility (DMD) were also calculated using NDF and ADF contents. Spearman's rank correlation was used to examine possible relationships between laboratory results and pastoralists' experience on grass quality. Cenchrus ciliaris, Chrysopogon aucheri, Digitaria milanjiana, Eragrostis papposa and Panicum maximum were the top five species based on LEBHP perception. There were indications of inconsistency in terms of LEBHP perception among the different pastoral communities. The chemical composition of all grass species showed significant (p<0.05) variation between sites, seasons and species. The results showed that the CP values for the Borana rangelands were in the range of 8.7% in the main rain season to 5.1% for the cold dry season. The fiber constituents were relatively low in the main rain season compared to the cold dry season. Overall, Digitaria milanjiana had the highest CP (16.5%) content, while the least was recorded with Heteropogon contortus (10.8) and Aristida adoensis (9.8%) during the main rain season. It seems that the spatial variability of landscapes within the wider geographical regions, soil properties and texture, and land-use patterns probably contributed to site differences in species quality. Generally, the RFV of individual grass species was significantly (p<0.05) varied between and within sites. The ranking of species by pastoralists according to their preferences by cattle was highly correlated with the chemical composition of laboratory results of individual grass species with 'r' values for CP (0.94), ash (0.95), NDF (-0.98), ADF (-0.93) and ADL (-0.93). We suggest the complimentary use of LEBHP and laboratory techniques in evaluating the nutritive quality of rangeland forage species for sustainable animal production.

• Animal cells and systems
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• v.5 no.4
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• pp.333-339
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• 2001

Common carp (Cyprinus carpio) and its aquaculture breed Israeli carp samples were obtained from two separate aquaculture facilities under the similar raising conditions during two years in the Kunsan National University, Korea. Genomic DNA was isolated from the common carp and Israeli carp for identification of genetic characteristics and genomic polymorphisms by polymerase chain reaction amplification of DNA using arbitrary primers. The arbitrary primer No.21 (ACTTCGCCAC) yielded the highest number of fragments with the average of 15.0 among the primers used in Israeli carp. A tota1 of 294 polymorphic products in common carp and 336 in Israeli carp were observed by random primers. The average number of polymorphic products generated by random RAPD primer No. 2 (GTAGAC-CCGT) showed 8.0 in Israeli carp. On average, each random RAPD primer produced 5.4 amplified polymorphic products in common carp and 6.2 in Israeli carp. An average genetic similarity (BS value) was 0.44$\pm$0.05 within the common carp and 0.32$\pm$0.04 within the Israeli carp. The degree of similarity frequency (BS) between two carps was 0.67 as generated by the primer No. 19 (GACGGATCAG). The average level of bandsharing was 0.57$\pm$0.03 between the two carps. Accordingly, the two carp populations were genetically a little distant. The electrophoretic analysis of PCR-RAPD products showed middle levels of variation between the two carp populations. This result implies that the genetic diversity among intra-population may be higher when compared with that between the two carps. The RAPD polymorphism generated by these random primers might be used as a genetic marker for populations or lines identification in important aquacultural carp.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.4
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• pp.276-284
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• 2012

Classification algorithms generally assume that the data is complete. However, missing values are common in real data sets due to various reasons. In this paper, we propose to use locally linear reconstruction (LLR) for missing value imputation to improve the classification performance when missing values exist. We first investigate how much missing values degenerate the classification performance with regard to various missing ratios. Then, we compare the proposed missing value imputation (LLR) with three well-known single imputation methods over three different classifiers using eight data sets. The experimental results showed that (1) any imputation methods, although some of them are very simple, helped to improve the classification accuracy; (2) among the imputation methods, the proposed LLR imputation was the most effective over all missing ratios, and (3) when the missing ratio is relatively high, LLR was outstanding and its classification accuracy was as high as the classification accuracy derived from the compete data set.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.3
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• pp.145-156
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• 2002

Business managers are often required to use LP problems to deal with uncertainty inherent in decision making due to rapid changes in today＇s business environments. Uncertain parameters can be easily formulated in the two-stage stochastic LP problems. However, since solution methods are complex and time-consuming, a common approach has been to use modified formulations to provide upper and lower bounds on the two-stage stochastic LP problem. One approach is to use an expected value problem, which provides upper and lower bounds. Another approach is to use “walt-and-see” problem to provide upper and lower bounds. The objective of this paper is to propose a modified approach of “wait-and-see” problem to provide an upper bound and to compare the relative error of optimal value with various upper and lower bounds. A computing experiment is implemented to show the relative error of optimal value with various upper and lower bounds and computing times.