• 충청수학회지
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• 제27권2호
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• pp.271-276
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• 2014

Recently, Taji [7] and Harms et al. [4] studied the regularized gap function of QVI analogous to that of VI by Fukushima [2]. Discussions are made in a finite dimensional Euclidean space. In this note, an infinite dimensional generalization is considered in the framework of a reflexive Banach space. To do so, we introduce an extended quasi-variational inequality problem (in short, EQVI) and a generalized regularized gap function of EQVI. Then we investigate some basic properties of it. Our results may be regarded as an infinite dimensional extension of corresponding results due to Taji [7].

• 대한산업공학회지
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• 제14권2호
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• pp.41-51
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• 1988

In this paper an efficient heuristic for the generalized assignment problem(GAP) is presented. A new lower bound that is slightly improved by adding the feasibility constraint is used to measure the quality of solutions obtained by the heuristic. The heuristic was tested on a number of large-scale random problems and a large sample of small problems. The heuristic appears to be better than the best previously existing heuristic for GAP. Its effectiveness in comparison of running times and closenesses to lower bound is discussed.

• 전기학회논문지
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• 제60권5호
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• pp.993-998
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• 2011

In this paper we suggest new criteria for the classification of the electrode gap between common and scan electrodes. The electrode gap is categorized as a short, middle, and long gap according to the criteria. Among these structures, we focus on the erase waveform of a mid-gap structure. we report an unstable discharge arising from the erase ramp period in a mid-gap structure. Based on the Vt close curve, we analyze the unstable discharge at various conditions. Our analysis reveals that the unstable discharge is ignited between surface electrodes and caused by un-erased wall charges accumulated on the outer edges of electrodes. By reducing the voltage level of the last sustain pulse, the problem is solved.

• 대한기계학회논문집
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• 제17권2호
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• pp.380-384
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• 1993

In precision wire electrode discharge machining by CAD/CAM, it is the most important problem on machining method to determine the wire electrode offset amout from the accurate calculation of discharge gap in order to increase the machining accuracy, after fixing the main machining conditions such as machining speed, wire tension, coolant conductivity, gap vlotage. The present study shows the relationships between discharge gap and main machining conditions by means of a series of experiment concerned with the gap using the workpiece of STD 11, and suggests the experimental eguation to calculate the accurate wire electrode offset amount under the given machining conditions for spot workers.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.628-632
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• 2001

Experimental approach was investigated to improve gear rattle noise of a small car. During the development of a small car serious problem occurred inside the transmission gear units. The transmission was a carried over system from a less powered predecessor. Several components of suspicion were investigated, and applied to reduce rattle noise. In general, backlash, the assembly gaps, and the clutch disk rattle induce gear rattle noise. Above mentioned improvements were applied to reduce the noise, but still problem remained. Meanwhile, the temperature inside the gearbox was reported to be unusually high and the life of transmission oil quality deteriorated drastically, Temperature increment caused the large gap between the bearing outer diameter and the transmission housing. Large gap made the gear shaft assembly move intermittently and impact each other. The tighter control of the assembly gap allowed the rotating shafts smoothly and reduced the gear rattle noise even in the high temperature range.

• 조명전기설비학회논문지
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• 제22권5호
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• pp.1-6
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• 2008

액정 멀티미디어 스크린은 효과적인 영상 정보를 표시하고 전달하는데 매우 중요한 역할을 한다. 그러나 이러한 시스템은 여러개의 액정 스크린을 사용하므로 이들 액정 스크린 사이에 갭이 발생하는 문제점이 있다. 이러한 문제점을 해결하기 위해서 본 논문에서는 바이너리 프레넬 렌즈를 사용하는 방법을 제시하였다. 바이너리 프레넬 렌즈를 사용하면 각각의 영상을 확대시키게 되며 결과적으로 갭을 최소화 할 수 있다. 바이너리 프레넬 렌즈의 설계 파라미터의 최적화 결과를 제시하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.421-422
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• 2007

The fringe electric field driven transflective liquid crystal display with dual orientation has a problem that the voltage-dependent transmittance and reflectance curves do not match each other, requiring a dual driving circuit to achieve a high electro-optic performance. Optimizations of the electrode structure in the array substrate and rubbing direction solve this problem so that the transflective display with a single gap and a single gamma curve for reflective and transmissive region is possible.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권2호
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• pp.49-54
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• 2002

Most single-Phase brushless DC (BLDC) motors have unequal air gap to eliminate the dead-point where the developed torque value is zero. However this partial increase of the air gap deteriorates the motor characteristics in cogging torque. Thus in this paper a new topology of unequal air gap is proposed to solve this problem. The topology is to use some pairs of equal or unequal air gaps. As a result, it is proved by the finite element analysis and experimental results that the single-Phase BLDC motor with the proposed air gap topology is very effective in reducing the cogging torque.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1127-1134
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• 2023

In this paper, we proposes a study on air gap control for magnetic levitation of transverse flux permanent magnet electromagnets. In general, mechanical systems have a high failure rate of bearings. Bearings in particular are problematic because they have high surface wear rate and degradations. To solve this problem, replacing the bearing with a magnetic levitation electromagnet system can provide lightweight and efficiency improvements. However, precise air gap control is essential to control the magnetic levitation electromagnet system. Therefore, in this paper, we identify the instable cause of gap control through a mathematical modeling and verify through experiment a control algorithm that can use compensation.

• 한국산업정보학회논문지
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• 제28권1호
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• pp.27-34
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• 2023

최상의 에이전트-작업 할당을 결정하는 문제는 조합 최적화(combinatorial optimization)의 대표적인 문제이자 NP-난해(NP-hard)임이 알려져 있다. 본 연구에서는 에이전트와 작업의 할당 시 결정되는 작업 수행 확률(completion probability)이 불확실한 상황에서의 문제를 다룬다. 에이전트나 작업 내부의 요인 혹은 시스템 외적인 요소로 인한 작업 수행 확률은 고정적이기보다 불확실성을 갖는 것이 일반적이다. 불확실성을 고려하지 않은 할당 결정은 변동성이 있는 현실 상황에서 효과적이지 않은 결정이 될 수 있다. 작업 수행 확률의 불확실성을 수학적으로 반영하기 위해 본 연 구에서는 추계적 계획법(stochastic programming)을 활용한 수리 모형을 제시한다. 본 연구에서는 효율적으로 문제를 풀기 위해 표본 평균 근사법(sample average approximation)을 활용한 알고리즘을 제안한다. 본 문제 해결 방법론을 이용해 효과적인 할당 결정과 상한값과 하한값을 구할 수 있고, 결과의 성능을 확인하기 위해 최적 격차(optimality gap)와 분산을 실험을 통해 제시한다. 이를 통해 알고리즘으로 구한 할당 결정의 우수성 및 강건성을 보인다.