• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.11
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• pp.769-776
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• 1987

This paper deals with the topological observability analysis and the development of an observable island identification algorithm for state estimation in power systems, by using the incidence matrix and bus voltage grouping. An analogy of the DC power flow method to the DC circuit analysis is introduced, and all the relationships between power flows and phase angles are replaced by the corresponding current-voltage relation. As a result, a set of topological measurement equation expressed in the form of the incidince matrix is derived for the topological analysis, and the observability test is carried out by examining the rand of the measuremint matrix. The integer Gauss elimination method is introduced in the determination of matrix rand, so that the proposed observability test yields a precise observability criterion without any nearly-zero pivot problem encountered in the conventional algorithm. Also, an observable island identification algorithm reduced its computational time in comparision with the conventional algorithms. The proposed algorithms have been tested for sample systems, and their practicability has verified.

• Journal of the Korean Home Economics Association
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• v.29 no.1
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• pp.37-49
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• 1991

The purpose of this study was to investigate the visual effects of clothing design. The specific objectives were: 1) to develop a clothing design evaluation instrument using semantic differential scales for the purpose of measuring visual responses with clothing design: 2) to identify the factor structure of the clothing design evaluation instrument: 3) to test the differences of perception to the clothing design depending on sex and knowledge about clothing design. The major findings were: 1. 37 pairs of descriptors of clothing form were found to include five factor dimensions (total variance:62.1%). Five major factors were found: attractiveness, practicability, elegance, comfort, hardness and softness. 2. for the visual evaluation of silhouettes, there were significant differences. H-line was explained by the simple image. A-line was explained by the comfortable image. V-line was explained by the mature and refined image. X-line was explained by the attractive and femine image and evaluated positively. 3. For the visual evaluation of observers, there were partly significant differences depending on sex and knowledge about clothing design in the observers' responses. But there were greater differences depending on sex than knowledge about clothing design in the observers' responses.

• International Journal of Automotive Technology
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• v.8 no.5
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• pp.593-598
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• 2007

A new continuously variable transmission for bicycles(B-CVT) is developed by using a traction drive mechanism having inner and outer spherical rotors. The B-CVT has high power efficiency, large torque capacity, improved drivability and good packageability. The ratio change mechanism for the B-CVT is very simple, in contrast with other traction drive CVTs. After completing a conceptual design, a performance analysis and a detail design, a prototype of the B-CVT has been manufactured. The prototype has rated power of 100 watts, pedal speed of 6 rad/s and an overall speed ratio of 1.0-4.0. A bench test and an actual bicycle test have been performed to verify the practicability of the B-CVT.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.500-505
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• 2002

Based on the real-time monitoring by remote sensing and dynamic management by GIS on agricultural land and water resources in arid area, we solved the practicability and popularization of small-scale spatial information service system. Through demonstration, the standards of spatial information service database of agricultural land and water resources is set up, and the agricultural land and water resources management system in Shehezi City of Xinjiang Autonomy is established, which provides periodically the spatial information services needed by agricultural production to support for sustainable development in arid area.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.709-714
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• 2002

This paper discussed and analyzed results of different classification algorithms for land use classification in arid and semiarid areas using CBERS-1 image, which in case of our study is Shihezi Municipality, Xinjiang Province. Three types of classifiers are included in our experiment, including the Maximum Likelihood classifier, BP neural network classifier and Fuzzy-ARTMAP neural network classifier. The classification results showed that the classification accuracy of Fuzzy-ARTMAP was the best among three classifiers, increased by 10.69% and 6.84% than Maximum likelihood and BP neural network, respectively. Meanwhile, the result also confirmed the practicability of CBERS-1 image in land use survey.

• Communications for Statistical Applications and Methods
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• v.22 no.5
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• pp.445-462
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• 2015

This article deals with the problem of estimation of the population mean in presence of multi-auxiliary information in two occasion rotation sampling. A multivariate exponential ratio type estimator has been proposed to estimate population mean at current (second) occasion using information on p-additional auxiliary variates which are positively correlated to study variates. The theoretical properties of the proposed estimator are investigated along with the discussion of optimum replacement strategies. The worthiness of proposed estimator has been justified by comparing it to well-known recent estimators that exist in the literature of rotation sampling. Theoretical results are justified through empirical investigations and a detailed study has been done by taking different choices of the correlation coefficients. A simulation study has been conducted to show the practicability of the proposed estimator.

• Journal of Korean Society for Quality Management
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• v.39 no.2
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• pp.305-312
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• 2011

Kano model has been widely used to identify and classify customer attributes of a product or a service. The first step of Kano model application is the derivation of customer attributes, and brainstorming has been used conventionally for the purpose. A typical advantage of brainstorming is to get many ideas in a relatively short period, but the practicability of the derived ideas are known to be not so good. The derivation of good and practical ideas is important for the successful use of Kano model. Wish list, bug list and forced connection method as well as brainstorming were applied to PMP(Portable Multimedia Player) in order to derive customer attributes. To compare the idea generation methods, the derived attributes are classified and compared using Kano model.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.7
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• pp.620-628
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• 2010

Using the responses of deck plate, a new bridge weigh-in-motion system has been introduced. The approach includes not only a systematic algorithm for the extraction of moment influence sequence but also a sensitivity-based system identification technique. The algorithm indentifies the influence sequence, the axle loads, and axle location of moving vehicles on a bridge, simultaneously. The accuracy and practicability of the algorithm have been examined experimentally for a folded deck plate on Yongjong Grand suspension bridge. It turns out that the two-dimensional effects of the behavior of deck plate should be considered for further accuracy improvement.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1049-1054
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• 2006

In many countries, methods to evaluate buildings have been investigated and practiced in order to reduce energy use and search for sustainable architecture while providing comfortable space for the users, in Korea, the current certification system has a short history, and has been improved for better practicability. Among many different factors in the certification system, the water resource problem is an important as the demand has been sharply increasing while reckless use and sewage treatment system causes the reduction of usable water. This study aims to find problems of water usage in building. water resource in the current certification will be used for the analysis of each factor in water resource, and the direction of improvement required in the certification in order to improve the water usage in buildigns will be proposed.

• Journal of Power Electronics
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• v.19 no.1
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• pp.79-88
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• 2019

The neutral-point (NP) voltage of three-phase three-level NP-clamped converters is needed for balance. To maintain NP potential and suppress ripple, a novel NP voltage balancing strategy is proposed in this work. The mechanism of NP voltage variation is studied first. Then, the relationship between the disassembly of zero level (O level) and NP current is studied comprehensively. On these bases, two methods for selecting one of three output phases for the disassembly of its O level are presented. Finally, simulation and experimental results verify the validity and practicability of the proposed algorithms.