• International Journal of Concrete Structures and Materials
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• 제10권sup3호
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• pp.109-121
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• 2016

Recently, as the use of high-performance materials and complex composite methods has increased, the need for advanced design specifications for steel-concrete composite structures has grown. In this study, various design provisions for ultimate flexural strengths of composite beams were reviewed. Design provisions reviewed included the load and resistance factor design method of AISC 360-10 and the partial factor methods of KSSC-KCI, Eurocode 4 and JSCE 2009. The design moment strengths of composite beams were calculated according to each design specification and the variation of the calculated strengths with design variables was investigated. Furthermore, the relationships between the deformation capacity and resistance factor for flexure were examined quantitatively. Results showed that the design strength and resistance factor for flexure of composite beams were substantially affected by the design formats and variables.

• 한국지진공학회논문집
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• 제23권4호
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• pp.201-209
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• 2019

Response modification factors of school facilities for non-seismic RC moment frames with partial masonry infills in 'Manual for Seismic Performance Evaluation and Retrofit of School Facilities' published in 2018 were investigated in the preceding study. However, since previous studies are based on 2D frame analysis and limited analysis conditions, additional verification needs to be performed to further apply various conditions including orthogonal effect of seismic load. Therefore, this study is to select appropriate response modification factors of school facilities for non-seismic RC moment frames with partial masonry infills by 3D frame analysis. The results are as follows. An appropriate response modification factor for non-seismic RC moment frames with partial masonry infills is proposed as 2.5 for all cases if the period is longer than 0.6 seconds. Also if the period is less than 0.4 seconds and the ratio of shear-controlled columns is less than 30%, 2.5 is chosen too. However, if the period is less than 0.4 seconds and the ratio of shear-controlled columns is higher than 30%, the response modification factor shall be reduced to 2.0. If the period is between 0.4 and 0.6 seconds, then linearly interpolates the response correction factor.

• 설비공학논문집
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• 제1권1호
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• pp.46-54
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• 1989

The purpose of this study is to obtain the dynamic characteristics of an absorption refrigerator powered by solar energy by experiments. Since the absorption refrigerator power by solar energy should have the characteristics which is suitable for the intermittence and rarity of solar energy, not only the characteristics of the steady state operations but also the partial load and the transient operations should be considered. The minimum available temperature of the storage tank should be known, and the absorption refrigerator can be suitably selected for air-conditioning systems. In this study, the experimental data of the transient state for on-off and warming-up operations has been obtained. Also the experiments are performed which test the minimum available temperature of the storage tank. The results show that it takes 1 hour to get to the steady state of the absorption refrigerator, and the minimum available temperature of the storage tank is about $68^{\circ}C$, and show that in the partial load operations the performance of the absorption refrigerator is improved by applying the modified control method to on-off operations.

• 한국음향학회지
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• 제39권2호
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• pp.113-119
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• 2020

자동차에서의 모터 사용 증가로 자동차 실내 음질(sound quality) 향상을 위해 모터 소음이 주요 관심사이다. 본 연구의 목적은 부하변화에 따른 모터 소음 성능을 나타낼 수 있는 인자를 제안하는 것이다. 이를 위하여, 파워스펙트럼과 라우드니스가 소음 성능을 나타내는데 적합하지 않음을 확인하였고, 브러쉬 마찰 성분과 관련된 부분라우드니스(PN_B)와 토크 리플 성분과 관련된 부분라우드니스(PN_R)가 소음 성능을 나타내는 인자로 파악되었다. 그리고 PN_B와 PN_R를 이용하여 부하에 따른 모터 소음의 변화 특성을 나타내기 위한 방법으로 모터 소음 성능 곡선을 제안하였다. 이 곡선은 소음 제어, 모터 선정 및 시스템 개선을 위한 가이드로 활용될 것으로 기대된다.

• 전자공학회논문지 IE
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• 제43권2호
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• pp.49-53
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• 2006

본 논문은 비디오 코딩에서 조절된 부분 영상 블럭의 차이값을 이용한 빠른 움직임 추정 알고리즘을 제안한다. 제안된 방법은 적은 계산량을 통하여 매우 정확한 움직임 벡터를 구할 수 있다. 실험을 통하여 제안된 방법은 전역 검색 방법(Full Search)가 매우 유사한 정확도를 보인 반면, 전역 검색 방법 보다 6에서 28배의 속도 향상을 보여주고 있다.

• Computers and Concrete
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• 제21권2호
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• pp.157-166
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• 2018

This article presents the flexural behaviour of reinforced fly ash (FA)-based geopolymer concrete (GPC) beams with partial replacement of FA for about 10% by weight with paper sludge ash (PSA). The beams were made of M35 grade concrete and cured under three curing conditions for comparison viz., ambient curing, external exposure curing, and oven curing at $60^{\circ}C$. The beams were experimentally tested at the 28th day of casting after curing by conducting two-point loading flexural test. Performance aspects such as load carrying capacity, first crack load, load-deflection and moment-curvature behaviours of both types of beams were experimentally studied and their results were compared under different curing conditions. To verify the response of reinforced GPC beams numerically, an ANSYS 13.0 finite element program was also used. The result shows that there is a good agreement between computer model failure behaviour with the experimental failure behaviour.

• 설비공학논문집
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• 제12권2호
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• pp.140-149
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• 2000

A comparative analysis was peformed on the operation cost at partial loads between ice storage systems with the two conventional control strategies, i.e., storage priority and chiller priority. The storage priority control is shown to be more economic for small cooling loads, while the chiller priority control is superior when the cooling load is as large as the design value. Based on this finding, a new control strategy is devised for an ice-storage system to minimize the operation cost at any cooling load. The new control strategy is found to be comparable to the chiller priority for large cooling loads, while it is more economic for small loads compared to the conventional control strategies. The practicality of the new control strategy is also confirmed through a performance test applying the new control strategy to an existing ice-storage system.

• Advances in concrete construction
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• 제8권1호
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• pp.33-37
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• 2019

The present investigation is mainly focused on studying the flexural behavior of reinforced geopolymer concrete (RGPC) beams under pure bending. In this study, copper slag (CS) was used as a partial replacement of fine aggregate. Sand and CS were blended in different proportions (100:0, 80:20, 60:40 and 40:60) (sand:CS) by weight. Fly ash and ground granulated blast furnace slag (GGBS) were used as binders and combination of sodium hydroxide (8M) and sodium silicate solution were used for activating the binders. The reinforcement of RGPC beam was designed as per guidelines given in the IS 456-2000 and tested under pure bending (two-point loading) after 28 days of ambient curing. After conducting two point load test the flexural parameters viz., moment carrying capacity, ultimate load, service load, cracking moment, cracking load, crack pattern and ultimate deflection were studied. From the results, it is concluded that RGPC beams have shown better performance up to 60% of CS replacement.

• 한국유체기계학회 논문집
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• 제18권4호
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• pp.30-35
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• 2015

This study analyzed the variations in the performance and operation of a 200 kW class micro gas turbine according to performance degradation of compressor and turbine. An in-house code, developed by the present authors and presented in the first part of these series of papers, were used for the analysis. The degradation of compressor and turbine were simulated by modifications in the their performance maps: mass flow rate, pressure ratio and efficiency were decreased from the reference values. Firstly, the variations in the operating conditions (air flow rate, pressure ratio) were predicted for the full load condition. Then, the same analysis were performed for a wide partial load operating range. The change in engine's performance (power output and efficiency) due to the component degradation was predicted. In addition, the change in the compressor surge margin, which is an important indicator for safe engine operation, was evaluated.

• 수산해양기술연구
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• 제50권3호
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• pp.292-300
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• 2014

The Laplace Transform solution is used as a mathematical model to analyse the thermal performance of the building constructed using different wall materials. The solution obtained from Laplace Transform is an analytical solution of an one dimensional, linear, partial differential equation for wall temperature profiles and room air temperatures. The main purpose of the study is showing the detail of obtaining solution process of the Laplace Transform. This study is conducted using weather data from two different locations in Korea: Seoul, Busan for both winter and summer conditions. A comparison is made for the cases of an on-off controller and a proportional controller. The weather data are processed to yield hourly average monthly values. Energy consumption load is well calculated from the solution. The result shows that there is an effect of mass on the thermal performance of heavily constructed house in mild weather conditions such as Busan. Building using proportional control experience a higher comfort level in a comparison of building using on-off control.