• 산업기술연구
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• 제27권B호
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• pp.185-192
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• 2007

Transcoding video proxy is necessary to support various bandwidth requirements for mobile multimedia and to provide adapting video streams to mobile clients. Caching algorithms for proxy are to reduce the network traffic between the content servers and the proxy. This paper proposes a Meta-tailed caching for transcoding proxy that is efficient to lower network load and CPU load. Caching of two different data types - transcoded video, and metadata - provides a foundation to achieve superior balance between network resource and computation resource at transcoding proxies. Experimental results show that the Meta-tailed caching lowers at least 10% of CPU-load and at least 9% of network-load at a transcoding proxy.

• 한국정밀공학회지
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• 제20권10호
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• pp.177-182
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• 2003

The front-end side members of automobiles absorb most of the energy in a case of front-end collision. The front-end side members are required to have a high stiffness together with easiness to collapse sequentially to absorb more impact energy. The axial static collapse test (5mm/min) was conducted by using UTM for form different types of members which have different cross section shapes; single hat, single cap, double cap, and double hat. The single hat shaped section member has the typical standard section, which the double hat shape section has a symmetry in the center to have more stiffness. As a result of the test, the energy absorbing characteristic was analyzed for different section shapes. It turned out that the change of section shape influence the absorbing energy, the mean collapse load and the maximum collapse load, and the relation between the change of section shape and the collapse mode.

• KIEAE Journal
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• 제5권3호
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• pp.25-31
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• 2005

Computer simulations were performed for Heating Ventilating and Air-Conditioning (HVAC) systems to figure out more efficient maintenance methods for the building used for adolescent trainees. This study aims at suggesting design alternatives for optimum operation and performing life cycle cost (LCC) for each alternative. First, the capacity of the heat source equipment was determined using annual maximum heating and cooling loads. Annual loads were calculated and applied to the alternative for the purpose of calculating annual energy cost. Second, several types of data were collected to predict energy cost. Finally, the pay back period for each alternative was calculated using total cost estimation during standard duration period. This study indicates that the absorption chiller that does not occupy most part of a mechanical room, and does not need much operation cost was most economical.

• Journal of Power Electronics
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• 제13권6호
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• pp.1070-1079
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• 2013

This paper develops an enhanced harmonic voltage compensator which is implemented with the aid of two repetitive controllers (RCs) in order to improve the output voltage performance of stand-alone distributed generation (DG) systems. The proposed harmonic voltage compensator is able to maintain the DG output voltage sinusoidal regardless of the use of nonlinear and/or unbalanced loads in the load side. In addition, it can offer good steady-state performance under various types of loads and a very fast dynamic response under load variations to overcome the slow dynamic response issue of the traditional RC. The feasibility of the proposed control strategy is verified through simulations and experiments.

• Wind and Structures
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• 제34권2호
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• pp.161-171
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• 2022

This paper presents a failure type assessment curve method to judge the failure type of transmission tower segments. This novel method considers the equivalent static wind load characteristics and the transmission tower members' load-bearing capacities based on numerical simulations. This method can help judge the failure types according to the relative positions between the actual state points and the assessment curves of transmission tower segments. If the extended line of the actual state point intersects with the horizontal part's assessment curve, the segment would lose load-bearing capacity due to the diagonal members' failure. Another scenario occurs when the intersection point is in the oblique part, indicating that the broken main members have caused the tower segment to fail. The proposed method is verified by practical engineering case studies and static tests on the scaled tower segments.

• Structural Engineering and Mechanics
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• 제87권1호
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• pp.95-106
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• 2023

This paper investigates the dynamic response of a functionally graded material (FGM) coated half-plane excited by distributed time harmonic loading. Three types of typical distributed surface loads, including uniform load, Hertz load, and square-root singular load, are considered. The mass density and elastic modulus of the FGM coating are supposed to be described by the exponential function. The material damping is modelled by a linearly hysteretic damping which is expressed by a complex modulus in the time harmonic motion. Using Fourier integral transform technique and numerical integral method, the effects of the excitation frequency, gradient index, damping, and load type on the dynamic stresses and displacements are discussed.

• 한국산학기술학회논문지
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• 제21권1호
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• pp.1-7
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• 2020

일반라멘가교의 거동에 영향을 미치는 여러 하중들 중에서 온도하중은 중요한 하중임에도 불구하고 이에 대한 충분한 검토가 부족한 실정이다. 일반라멘가교의 온도하중에 의한 응력을 감소시키기 위해서는 열변형으로 인한 거더의 수평변위는 자유롭고, 발생내력은 최소가 되도록 하여야 한다. 슬라이딩가교는 일반라멘가교와 달리 온도하중으로 인한 축방향 변형을 허용하여 축응력을 감소시키고 휨응력은 전달시키는 구조이다. 본 연구는 슬라이딩거더를 가진 라멘가교의 온도거동과 구조효율성을 일반라멘가교와 비교하여 분석하였다. 분석을 위하여 경간장 10, 20, 30, 40m, 교각높이 2, 4, 6m의 경우에 대하여 일반라멘가교와 슬라이딩가교의 구조해석을 수행하였다. 하중은 연직 고정하중과 축방향 온도하중을 재하하고, 마찰계수는 매끄러운 상태와 윤활상태의 중간인 0.4를 적용하였다. 구조해석결과 슬라이딩가교는 온도하중 증가에 관계없이 경간장 증가에 따라 응력이 증가하며 일반라멘가교는 온도가 증가하거나 경간장이 증가할수록 응력이 증가하였다. 일반라멘가교에 비해 슬라이딩가교의 거더 중앙부 응력은 20에서 50%, 교각 하단부 응력은 50에서 90% 감소하였다. 따라서 온도하중이 작용하는 슬라이딩가교는 축응력이 감소하며 동일 제원의 일반라멘가교와 비교하여 구조효율성을 확보할 수 있다.

• 대한치과보철학회지
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• 제22권1호
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• pp.23-32
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• 1984

The effects between preexisting four types and one that author had designed of posterior palatal seal on the retention of denture base were compared and observed from six systemically healthy edentulous subjects. Using one without posterior palatal seal as the control, the retention of each type was measured and analyzed six times with cantilever type Load cell after adaptation of denture base, which were constructed with usual manner. The following results wear obtained. 1. Morphological and positional changes of posterior palatal seal effected on denture retention. 2. No specific type showed most desirable effect in every experimental subject. 3. Experimental subject I, II, VI showed higher retention on the control in every type. 4. In five types of posterior palatal seal, for subject III, VI F types and for subject II, V C types were most effective. 5. In each experimental subject F type showed higher retention than the control.

• Structural Engineering and Mechanics
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• 제7권4호
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• pp.361-375
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• 1999

This paper presents an analytic method of examining the out-of-plane vibration of continuous curved beam on periodical supports. The orthogonality of two distinct sets of mode shape functions is derived. The forced vibration of beam due to moving loads is examined. Two types of moving loads, which are concentrated load and uniformly distributed load, are considered. The response characteristics of beam induced by these loads are investigated as well.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.485-488
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• 2000

In this study, the fatigue characteristic of spot weld specimen was studied by using the various specimen. The specimen types were tensile shear specimen welded one spot and two spot, and cross tension. The tensile tests and fatigue tests were executed to know the mechanical properties under static and fatigue load condition. In addition, the relationship was illustrated by finite element method.