• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.708-719
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• 2007

In case of indoor gymnastics training floor, in view of its characteristics, since it is simultaneously required the related smooth communication between the coach and the player, also the acoustic performance regarding to the clearness of music, besides the sport activity, the consideration about the acoustic character has entered the stage as an indispensable element. On such viewpoint, recently constructed dome-typed gymnastic training floor was optimized acoustic design with remodeling through acoustic simulation test. And acoustic satisfaction degree and reaction was attempted to investigate about the gymnastics training floor estimating value of human's psychological(sensual) degree using auralization that enables to experience the virtual sound field at the stage of design. As the result of investigation about the research on the space of object, it could be known that the valuation regarding to the acoustic performance of 'after-improvement' was distinctly more refined than that of 'before-improvement'. It is now considering that such result of the study can be utilized as the useful data which enables to improve the retrenchment effect of the construction cost as well as the acoustic capability, by means of the prediction control on the acoustic problem from the stage of design, for the occasion when the similar indoor sport gymnasium is planning to build for the near future.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.277-280
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• 2006

Most real world design evaluation and risk-based decision support combine quantitative and qualitative (linguistic) variables. Decision-making based on conventional mathematics that combines qualitative and quantitative concepts always exhibit difficulty in modelling actual problems. The successful selection process for choosing a design/procurement proposal is based on a high degree of technical integrity, safety levels and low costs in construction, corrective measures, maintenance, operation, inspection and preventive measures. However, the objectives of maximising the degree of technical performance, maximising the safety levels and minimising the costs incurred are usually in conflict, and the evaluation of the technical performance, safety and costs is always associated with uncertainties, especially for a novel system at the initial concept design stage. In this paper, a design-decision support framework using a composite structure methodology grounded in approximate reasoning approach and evidential reasoning method is suggested for design evaluation of machinery space of a ship engine room at the initial stages. It is a Multiple Attribute Decision-Making (MADM) or Multiple Criteria Decision Making (MCDM) framework, which provides a juxtaposition of cost, safety and technical performance of a system during evaluation to assist decision makers in selecting the winning design/procurement proposal that best satisfies the requirement in hand. An illustrative example is used to demonstrate the application of the proposed framework.

• KIEAE Journal
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• v.12 no.1
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• pp.113-118
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• 2012

The photovoltaic is one of the most important sustainable technologies appliable to architectures. The power performance mainly depends on the installation conditions of them. This study aims to evaluate the power performance of photovoltaic system by the installation conditions, the tracking methods and reflecting mirrors. For the study, the Solar Pro computer simulations have been conducted on installation angles, solar azimuth and solar altitude. Also, the field mock-up tests are performed to of its application to verify the simulation results. Both the results of the experiment and the simulation have proved that the efficiency of 90-degree fixed angle method was higher than that of 30-degree fixed angle, the efficiency of altitude tracking was better than that of azimuth tracking method, and changing both the altitude and the azimuth together is more efficient rather than the shortened tracing way. In addition, the light-concentrating method in which the incidence angle of the sun is controlled by an adhered reflector has been analyzed to have better efficiency than the general method of tracing according to the orbit of the sun. Therefore, this thesis is expected to offer the basic data to set a more effective tracing-type of photovoltaic power generation system in the future. For this, more researches are to be conducted hereafter on a high efficiency drive motor and the establishment of an economic system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.80-87
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• 2004

Active control of on-orbit spacecraft jitter is a significant problem for future spacecraft mission requiring stringent pointing performance. Jitter is major disturbance source degrading payload pointing performance. Both passive and active jitter isolation techniques have been studied during the last decade. We present active jitter isolation for a model device in this work. The device provides active control capability by 3 degree-of-freedom control of payload in feedback control strategy. Mathematical modeling of the device is pursued which is naturally used for a baseline controller design. Simulation results are used to validate the designed control law.

• Aerospace Engineering and Technology
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• v.10 no.1
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• pp.98-106
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• 2011

This paper is summarized for designing launch vehicle autopilot structure with attitude angle command from guidance algorithm and for evaluating performance of autopilot using launch vehicle six-degree of freedom simulation program. The suggested autopilot has heritage from KSR-III/KSLV-I upper stage autopilot designing experience, and it has two design point. The one is, it must have same performance with KSR-III/KSLV-I upper stage autopilot, the other is, it must be simple autopilot structure and use low number of variable to apply on-board system. It is evaluated the performance using launch vehicle six-degree of freedom simulation program in case of roll maneuvering and no roll control flight condition.

• Asia pacific journal of information systems
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• v.13 no.3
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• pp.173-193
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• 2003

As the interest in the business-to-business(B2B) electronic commerce is increasing, some companies are participating in the B2B eMarketplaces(electronic marketplaces). The eMarketplace has an effect on the method of B2B transactions or the purchasing performance. The academy and the industry are focused on the cause and the result of this effect. The purpose of this research is to analyze the effects of the relational exchange with eMarketplace on the purchasing performance, considering the supply externality and system integration as intervening variables. This study investigates the second-order effect of eMarketplace in which the degree of improvements in two aspects of purchasing activity(price reduction, purchasing efficiency) depends on the degree of the relational exchange with eMarketplace, namely, the governance of eMarketplace. Our hypotheses on this second order effect were supported. We found that the higher the relational governance, the lower in price reduction, and the better in purchasing efficiency. In more details, the high relational governance lowers the supply externality, and in turn deteriorates the improvement in price reduction. Meanwhile, the high relational governance accelerates the information system integration, and brings the better purchasing efficiency. Our findings suggest that organizations can improve their purchasing activities better if they choose the appropriate eMarketplace governance.

• Journal of Families and Better Life
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• v.14 no.2
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• pp.215-226
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• 1996

The purpose of this study is to provide basic data needed to examine the relationship between father and son by investigating correlations among male college students' perceptions of the degree of closeness to their fathers their fathers' paternal role and their own paternal role in the future. The subjects of this study were 474 male college students(sophomores juniors and seniors) from Seoul and Daegu. The questionaire the means of this research is composed of classified questions on related studies and on the researches of reference literatures, Statistical methods applied for data analysis were frequencies mean standard deviation Pearson's correlation. Major findings are as follows; 1) When a son perceives that he is on intimate terms with his father he perceives that his father performs paternal role well. Intimate relation between the father and the son can be considered essential to good performance of paternal role. 2)When a son perceives that he is on intimate terms w th his father he believes that he will perform his own paternal role will in the future. That is the son seems to accept his future paternal role positively as he feels close to his father. 3) Male college students who perceive their fathers' paternal role is properly performed tend to believe they will perform their own paternal role well in the future. Judging from the relation between fathers' performance of paternal role and sons' perception of thir future paternal role we can say good performance of paternal role is important is building up sons' affirmative perception of paternal role.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.103-106
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• 2006

This study investigates spalling properties of 60MPa class, high performance concrete, made with the various influential parameters, such as, blaine of cement, mineral admixture and polypropylene(PP) fiber contents. Totally 21 parameters of ${\phi}100{\times}200mm$ in size was fabricated; three specimens for variance in blaine of cement, 4 specimens for combination of mineral admixture type, along with 0.05, 0.1, 0.15% of fiber adding ratio. After that, one hour unloading fire test was conducted, and then spalling appearance and spalling degree of specimens was examined. Test showed that a specimen made with high blaine of cement(H) improved early strength but exhibited similar value to a specimen made with low blaine(L) at the age of 28 days, thus indicating comparable spalling appearance. In conclusion, spalling easily occur in higher strength and smaller particle shape of cement and mineral admixture.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.119-122
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• 2000

Recently polymer insulators are being used for outdoor high voltage applications. Polymer insulators for transmission line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. Polymer insulators are a relatively new technology, but their expected life is still unknown. Therefore these estimating technique are very important. Their life time is related to weathering and operating condition. Multi-aging test is requested because aging factor is occurred by multi-aging than unique aging. The aging test about polymer insulators have mainly carried out by IEC 61109. This paper presents multi-stress chamber experiments and tracking wheel test to examine the tracking and erosion performance of polymer insulator for transmission. Multi-stress testing is able to demonstrate deficiencies of polymer insulator materials and designs, including the nature of interfaces in insulation design. We have investigated IEC 61109 Annex C (5000h aging test) and CEA tracking wheel test as test methods of artificial accelerated aging. The aging degree of polymer insulator is estimated by leakage current, measurement of hydrophobicity degree, damage conditions of insulator surface, withstand voltage test etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.9
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• pp.1041-1043
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• 2016

This letter proposes a new blind fractionally spaced equalization (FSE). The conventional linear program (LP) FSE reduces the degree of freedom (DOF) by abandoning many equalization filter taps, which causes severe performance degradations. We use singular value decomposition (SVD) to obtain the signal subspace and to fully utilize all samples for performance improvement. The proposed scheme has similar performance with the nuclear norm minimization and has as low complexity as the LP equalizer.