• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1713-1715
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• 2003

This paper describes an LED module for a desk lamp using 1[W] high flux while LEDs. The optimum length of the module is obtained from the lighting simulation of the target area of $500{\times}500[mm]$ on the desk, which in turn determines an optimum separation between LEDs. The main issue is to find the optimum separation which gives good illuminance uniformity and high coefficient of utilization at at various reflector structures. Two module configuations of linear and ring types are compared. As a result, good illuminance uniformity is obtained in the case of the ring module. The mofied twin type, however, gives better performance than the ring module, and shows the most performance at an separation angle of around $30^{\circ}$.

• 설비공학논문집
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• 제16권3호
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• pp.241-249
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• 2004

A parametric study on the scroll wrap configuration factors of a $CO_2$scroll compressor for heat pump water heater has been carried out. Since there are 7 scroll wrap design parameters and 5 equations relating them, two of the design parameters can be selected as independent parameters. In this study, the wrap thickness and orbiting radius are chosen as independent ones. Computer simulation program has been used to estimate the compressor performance at various combinations of the scroll wrap design parameters. It has been found that there exists optimum combination of the wrap parameters for the highest compressor performance over analyzed ranges of the design parameters.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.53-61
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• 2014

In this paper, we proposed covariance weight matrix using SPT matrix in order to accurate target estimation. We have estimated a target using modified covariance matrix and beam steering error method. We have minimized beam steering error in order to estimation desired a target. This method obtain optimum covariance weight using modified SPT matrix. This paper of proposal method is showed good performance than general method. We updated a weight of covariance matrix using modified SPT matrix. We obtain optimum covariance matrix weight to application beam steering error method in order to beam steering toward desired target. Through simulation, we showed that compare proposal method with general method. It have improved resolution of estimation target to good performance more proposed method than general method.

• Journal of Biosystems Engineering
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• 제5권1호
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• pp.43-50
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• 1980

The milling plants in Korea have been generally used the paddy-separator that operated in accordance with the principle of sieving action. This type of paddy separator was considered as inefficient, especially in relation to the new high-yielding varieties which have different size characteristics within their varieties and also as compared to traditional varieties. With the installation of modern paddy separator it may be possible to increase the overall milling system efficiency and to reduce the grain loss. This study was intended to identify and define important parameters required for assessing the separation performance of a tray-type paddy separator and to determine the optimum conditions of the inclination of separator-table. The results of the study were summarized as follows : (1) Separation performance can be given by use of many parameters found from the measurement of separator outputs. such as upper-tail recovery $(\varepsilon)$, purity of upper-tail $(\gamma)$ , separation recovery of brown rice $(\alpha)$, separation recovery paddy $(\beta)$, and efficiency of separator $(\epsilon)$, Among these para-meters , $\varepsilon$, $\gamma$, $\alpha$ and $\beta$, were designated , respectively, their independent properties of the paddy separator. In addition, their modes of variation due to a varied inclination of the separation table did not indicated in the same direction . However, the efficiency of separator had an advantage to indicate the overall characteristics of the separator performance with a clear optimum inclination condition of the separator table. (2) The optimum feed rate and maximum efficiency of the separator did not occur at the identical inclination of the separator table. Thus, for its practical operation it is necessary to compromise between the qualitative and quantitative performances of the separator. (3) The optimum setting of the separator table tested in the study showed to occur at its inclination of approximately $26^\circ<$/TEX> for the front and $8^\circ<$/TEX> for lateral.

• 대한기계학회논문집
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• 제16권11호
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• pp.2196-2202
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• 1992

본 연구에서는 초전도 양자 간섭장치(SQUID, superconductiong quantum inte- rference device)를 냉각시킬 수 있는 정도의 소용량(3.995K에서 0.1W)의 GM/J-T 냉동 기에 대하여 요구되는 냉각용량을 만족시키면서 최대의 성능을 나타낼 수 있는 열교환 기의 면적배분 조건을 구하였다. 즉 냉동 성능을 알고 있는 상용 2단 GM 냉동기와 소형 극저온 냉동기에 널리 사용되는 열교환기로 이루어진 복합적인 GM/J-T 냉동기에 대하여 열교환기 총면적이 주어졌을 때, J-T 회로내의 냉매(헬륨)의 유량과 각 열교환 기 전열 면적의 비를 변수로 최적설계를 행하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.109-112
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• 1989

Gun system operation is represented as a first-order Markov process, and an optimum linear filter is derived for closed-loop control of mean square error. Potential improvement is then estimated by contrasting the variance in performance and the auto correlation for open-loop system with that for the optimum linearly corrected process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.677-678
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• 2009

• 한국환경보건학회지
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• 제34권3호
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• pp.233-239
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• 2008

In order to improve reactor performance of existing sewage treatment plants, the feasibility of enhancing reactor performance by bioaugmentation using EM as bioaugmentation agent and the effects of anoxic: oxic time ratio on reactor performance were investigated. Continuous and intermittent aeration modes were compared under the 6 hr of HRT. Three different types of intermittent aeration modes, that is, 15 min, of anoxic:45 min of oxic, 30 min of anoxic: 30 min of oxic, and 45 min of anoxic: 15 min oxic respectively were chosen as test modes to study the effects of anoxic : oxic time ratios on reactor performance. The optimum anoxic: oxic time ratio was 30 min:30 min when considering simultaneous removal of organic, nitrogen and phosphorus. When applying EM into a continuously aerated reactor under the varying dosing rates of 50-200 ppm, reactor performance in terms of organic and nitrogen removal efficiencies was not improved at all. Nitrogen removal efficiency was increase when the EM dosing rate was increased. However the degree of improvement was slight when the EM was injected above 100 ppm. However optimum phosphorus removal was found at the EM dosing of 200 ppm. Thus it was found that optimum injection concentration of EM is 200 ppm. It is apparent that putting EM into a sewage treatment plant significantly affects the T-N removal efficiency of the reactor by enhancing denitrification efficiency especially in operational conditions of relatively long anoxic periods. To achieve reciprocal condition in a reactor with intermittent aeration it is necessary to enhance the reactor performance by EM injection. In the case of modifying existing continuously aerated reactors into intermittent aerated reactors, it is obvious that operating costs of aeration would be reduced by reducing aeration time when compared with existing conventional sewage treatment plants.

• Smart Structures and Systems
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• 제20권4호
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• pp.461-472
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• 2017

Explicit design formulae of liquid column vibration absorber (LCVA) for suppressing harmonic vibration of structures with small inherent structural damping are developed in this study. The developed design formulae are also applicable to the design of a tuned mass damper (TMD) and a tuned liquid column damper (TLCD) for damped structures under harmonic force excitation. The optimum parameters of LCVA for suppressing harmonic vibration of undamped structures are first derived. Numerical searching of the optimum parameters of tuned vibration absorber system for suppressing harmonic vibration of damped structure is conducted. Explicit formulae for these optimum parameters are then obtained by a series of curve fitting techniques. The analytical result shows that the control performance of TLCD for reducing harmonic vibration of undamped structure is always better than that of non-uniform LCVA for same mass and length ratios. As for the effects of structural damping on the optimum parameters, it is found that the optimum tuning ratio decreases and the optimum damping ratio increases as the structural damping is increased. Furthermore, the optimum head loss coefficient is inversely proportional to the amplitude of excitation force and increases as the structural damping is increased. Numerical verification of the developed explicit design expressions is also conducted and the developed expressions are demonstrated to be reasonably accurate for design purposes.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.209-212
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• 2005

In this paper, based on a detection criterion proposed recently, we investigate the performance of selective rake receivers (SRRs) in fading environment exhibiting impulsive nature. Optimum and suboptimum SRRs for the impulsive fading channel are derived, and suboptimum SRRs with reduced complexity are obtained for practical purposes. Simulation results confirm that, when the noise is impulsive the SRRs designed for impulsive noise offer performance improvement over those optimized for Gaussian environment. The suboptimum SRR is observed to exhibit almost the same performance as the optimum SRR.