• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.242-247
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• 2003

An experimental study presents characteristics of combustion in a combustion chamber by port deactivation valve for economy and emissions standards. In order to use combustion properties data it is necessary to build some data base, which use cylinder pressure sensor, etc. Port deactivation valve has been developed to satisfy requirement of achieving sufficient swirl generation to improve the combustion. A feasibility and necessity of combustion pressure based cylinder spark timing control has been examined. So, this was obtained the Coefficient of Variation(COV) and the mass-burned(MFB). The characteristics of pressure ratio fraction is similar to that of mass-burned fraction. Using the results of the test, the effects of the combustion chamber can be improved combustion stability by port deactivation.

• Structural Engineering and Mechanics
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• 제58권6호
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• pp.989-999
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• 2016

Moist curing of concrete is a time consuming procedure. It takes minimum 28 days of curing to obtain the characteristic strength of concrete. However, under certain situations such as shortage of time, weather conditions, on the spot changes in project and speedy construction, waiting for entire curing period becomes unaffordable. This situation demands early strength of concrete which can be met using accelerated curing methods. It becomes necessary to obtain early strength of concrete rather than waiting for entire period of curing which proves to be uneconomical. In India, accelerated curing methods are used to arrive upon the actual strength by resorting to the equations suggested by Bureau of Indian Standards' (BIS). However, it has been observed that the results obtained using above equations are exaggerated. In the present experimental investigations, the results of the accelerated compressive strength of the concrete are used to develop the regression models for predicting the short term and long term compressive strength of concrete. The proposed regression models show better agreement with the actual compressive strength than the existing model suggested by BIS specification.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1989년도 가을 학술발표회 논문집
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• pp.34-39
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• 1989

Recent trends in design standards development have encouraged the use of probabilistic limit sate design concepts. Reliability analysis adopted in those advanced countries have the potentials that they afford for symplifying the design Process arid placing it on a consistent reliability based for various construction materials. This study is proposed in the reliability analysis of plane frame structures using second-order moment method(Level-II they). Lind-Hasofer's minimum distance method is use in the derivation of an mathematical algorithm as well as an determination of Correlation cofficients, reliability index and total reliability index depending on the multiple failure modes. In addition. This study is employed as a practical tool for the approximate reliability analysis. Results of the numerincal analysis showed that the difference between the reliability index of the failure probability of the multiple failure modes and the total reliability index of the failure probability with the simultaneous failure modes deviated nearly 3∼10% depending on tile performance functions.

• 대한안전경영과학회지
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• 제16권3호
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• pp.201-207
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• 2014

This study is aimed to improve safety of ladle in the metal products manufacturing industry. Burns may occur from spills, spatters or eruptions of hot metal from ladles during pouring or transporting. According to the statistics of occupational accidents about the ladle, many victims were exposed to or contacted with extreme temperatures. The many fatal injuries occurred as a result of unexpected discharging of molten metal due to tipping over ladles. To prevent ladles from turning over, the trunnion axis shall be located below the center of gravity of the ladle at all operating condition. For this purpose, the equation is proposed to calculate the minimum location of a trunnion axis for definite static stability when tilting.

• 전기학회논문지
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• 제65권6호
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• pp.995-1000
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• 2016

Minimum Energy Performance Standard(MEPS) has been adapted in Korea since 2008. For at least 37 kW, IE3 efficiency class motors are now mandatory in Korea. IE4 level regulation is expected in a few years. Foreign companies are already selling IE4 class motors in the market, and the discussions on IE5 have already started. The efficiency standard of variable speed motors is scheduled for publication shortly. Recently, discussions are now beginning to prepare for IE5 in Korea. In this paper, author reviews the policies associated with a high efficent electric motors by reference to both domestic and international standards, and reviews the research direction to prepare for IE5.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.35-36
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• 2012

BIM technology accomplished quantitative development being utilized in various disciplines. However, it is necessary to develop environment and requirement for qualitative improvement of BIM-based project in current transitional period of adopting BIM. The purpose of this study is to develop and apply of quality control requirement for improving the quality of BIM-based architectural design through case study. In particular, by focusing on BIM quality control and its relevant subjects, the minimum standards for BIM quality management are suggested. Also, BIM template is suggested to support the effective application of BIM-based architectural design.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.514-517
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• 2003

Polymeric suspended insulators for subway and electrical track line had been designed and manufactured. The main elements to design polymeric insulators were the insulation ability and the optimal structure. To get the insulation ability, electrical and mechanical tests according to standards had done on housing rubbers and FRP cores and selected the sample with best properties as a insulator. The insulator shape and fitting parts with minimum electrical stress was simulated by FEM electrical field analysis program. The manufactured insulator set had been tested and estimated the electrical and mechanical according to ES and KS, and showed good characteristics in these tests.

• 한국표면공학회지
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• 제36권3호
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• pp.284-289
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• 2003

In this study, the prediction on the quality of tools after coating process has been investigated. Under different coating conditions, cutting resistances have been obtained and analyzed with a tool dynamometer to provide optimized coating conditions. The optimized coating conditions Lhave been computed with the most effective factors found by S/N ratio of Taguchi method. To evaluate the influence of the factors on cutting efficiency through the minimum of number of experiment times, the way of neural network design using Taguchi method has been employed.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.151-158
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• 1998

This paper presents an optimal decision model for minimizing the life-cycle cost of steel box girder bridges. The point is that it takes into account service life process as a whole, and the life-cycle costs include initial (design, testing, and construction) costs, maintenance costs and expected failure costs. The problem is formulated as that of minimization of expected total life-cycle cost with respect to the design variables. The optimal solution identifies those values of the decision variables that result in minimum expected total cost. The performance constraints in the form of flexural failure and shear failure are those specified in the design code. Based on extensive numerical investigations, it may be positively stated that the optimum design of steel box girder bridges based on life-cycle cost approach proposed in this study provides a lot more rational and economical design, and thus the proposed approach will propose the development of new concepts and design methodologies that may have important implications in the next generation performance-based design codes and standards.

• JSTS:Journal of Semiconductor Technology and Science
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• 제8권3호
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• pp.200-209
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• 2008

This paper describes bandwidth linearization techniques in phase-locked loop (PLL) design for common-clock serial link applications. Utilizing a continuously tunable single-input dual-path LC VCO and a constant-gain phase detector, a proposed architecture is well suited to implementing PLLs that must be compliant with standards that specify minimum and maximum allowable bandwidths such as PCI Express Gen2 or FB-DIMM applications. A prototype 4.75 to 6.1-GHz PLL is implemented in 90-nm CMOS. Measurement results show that the PLL bandwidth and random jitter (RJ) variations are well regulated and that the use of a differentially controlled dual-path VCO is important for deterministic jitter (DJ) performance.