• Journal of the Korean Society for Precision Engineering
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• v.19 no.2
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• pp.160-170
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• 2002

Retroreflective article is different from other reflecting objects as it returns the incidence ray to the near of its source. This characteristic makes the retroreflectors have many applications in reflective highway signs, reflective vests, and other safety-relaxed items. These articles may have various shapes. However, the quantitative evaluation of performance for the best shape of retroreflector needs much time and cost for manufacturing prototypes and for performance experiments. In this work, we have developed a program for simulating the trace of ray entered into a retroreflective element, in order to determine the optimal shape of retro-reflection. We have also proposed new performance criterion of retroreflective articles, which can confide the range of incidence angle, instead of the criterion with the merely retroreflective strength.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.305-307
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• 2016

The purpose of this paper is to determine the optimal values of the gain parameters used in the tracking module for a highly dynamic warship. The algorithm of the tracking module uses the ${\alpha}-{\beta}-{\gamma}$ filter to compute accurate estimates and update the state variables, that is, positions, velocity and acceleration. The filtering coefficients ${\alpha}$, ${\beta}$ and ${\gamma}$ are determined from set values of the damping parameter, ${\xi}$. Optimization is achieved by plotting a range of the damping parameter ${\xi}$ against the corresponding residual error and then selecting the best value of ${\xi}$ with the minimum residual error. Optimal values of the smoothing coefficients are subsequently computed from the selected damping parameter, ${\xi}$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4B
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• pp.215-223
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• 2008

Retransmission signals from relays to destination when the destination fails to decode received signal from the source in Automatic Repeat Request (ARQ) protocol make the destination receive signals more reliably. With using omni -direction antenna in the practical system, in communication range of both the source antenna and the destination antenna, there are some relays that can be used to transmit signal to the destination. However, using all relays to transmit signal consume power and bandwidth. In this paper, we propose a new protocol in which the best relays are chosen based on threshold of distance from the source to the relay and the relay to the destination when the relays use decode- and forward (DF) protocol. Simulation results prove the efficiency of the protocol when we compare using only the best relays with using all relays to transmit signal to the destination.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.64-65
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• 2011

The ac power conversion inverter provides the ac power to ECR device for wireless power transfer. In this paper, the operating efficiency of the class-${\Phi}_2$ resonant inverter has been studied through by experiment for optimal design. Its switching frequency is 1MH and the input voltage is 96V which is the output voltage of LLC resonant converter. And its output voltage is 230Vp-p. The efficiency is measured up to 84%.

• BMB Reports
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• v.33 no.4
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• pp.353-357
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• 2000

A new assay method of ${\alpha}-Oxidase$ (fatty acid : oxygen dioxygenase, 1-decarboxylating) was developed using a bioluminescence reaction system of marine luminous bacterium, Photobacterium phosphoreum. ${\alpha}$-Oxidase was isolated from a cucumber (Cucumis sativus). Pentadecanoic acid was used as a substrate, and the product, tetradecanal, was analyzed with a bacterial luciferase-coupled reaction. Initial light intensity was directly related to the concentration of tetradecanal in the range of 1 nM to 10 ${\mu}M$. Optimal pH and temperature were 7.5 and $25^{\circ}C$, respectively. Optimal pentadecanoic acid concentration in a standard assay of ${\alpha}$-oxidase was 0.1 mM. The Km value of pentedecanoic acid was $85{\mu}M$. This method is straightforward, rapid, convenient, and easy. Its needs no treatment or extraction of reaction mixture.

• 한국전산유체공학회:학술대회논문집
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• 2000.05a
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• pp.73-77
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• 2000

Small-sized fans for cooling electronic components are usually produced by injection molding in unified form including blade and hub. However, in case of middle and large-sized fans, they deal ill various products with varied numbers of blade or stagger angles after designing a single blade by molding or aluminum die casting. At this occasion, it is necessary to study design method for high-performance axial fans can be operated with various numbers of blades or stagger angle using unique blade for specified conditions. Therefore, the goal in this study is developing a optimal design method which improves performance of axial fans within the large range of operating by single blade.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1063-1066
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• 1992

As the adjustable speed drives by means of PWM inverter are applied to a wider field of industries, the demands for lower acoustic noise caused by modulation is becoming more intense. With the development of high speed power semiconductor device such as the IGBTs, a higher carrier frequency can be adopted to increase the switching frequency to the supersonic range. The optimal magnitude of this signal is determined so that the sideband components near the carrier frequency are minimized

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1422-1428
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• 2004

In this paper, computer simulation model of handrail band including pulley-driving system is developed to calculate handrail slippage. This handrail simulation model is validated with test result within operating range and used to predict its slippage behavior with respect to variation of 4 different design parameters considering the applicability into the real handrail system. Based upon this parameter study, optimal condition for handrail slippage improvement is proposed without time-consuming and costly experiments of the real handrail system. And then performance improvement of handrail slippage complied with safety code is achieved after applying the optimal condition into the real handrail band system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.29-37
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• 1994

It is reported that north Korea has already developed 1,500 to 2,000-km-range Scud missile. As a defensive strategy against Scud attack on military and civilian facilities the military authorities are considering deployment of Patriot missile. This paper deals with its optimal deployment strategy. In this problem a Patriot missile which has multiple-facility responsibility may be able to protect each of its assigned facilities only with a certain probability, not absolute protection, and it may not be adequate to have only a single missile protect a facility, either because of its operational reliability or because of its limited availability at any given point in time. We formulate this problem into the probabilistic partial set covering model developed by Sherali and Kim. The applicability, verification and validation of the model are tested via an abbreviated case study.

• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.165-170
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• 1998

Lipase-catalyzed esterification of n-butyl oleate was carried out in n-hexane as a model reaction. The optimal activity of Candida rugosa lipase was shown in a water activity ($a_w$) range of 0.52 to 0.65 at $30^{\circ}C$. The water produced from the esterification was removed by a tubular type pervaporation system. The rate of ester formed from the enzymatic esterification was allowed to be the same as the rate of water removal by maintaining an optimal $a_w$ of the reaction system using an on-off dewatering control device. The reaction rate and yield with a$a_w$ control were increased two folds higher than the respective values for the uncontrolled reaction.