• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2176-2182
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• 2014

In this paper, a phase locked loop with suppressed power supply noise has been proposed. The added negative feedback loop of voltage controlled oscillator(VCO) and power noise detector suppresses the power noise induced jitter variation of VCO down to 1/3. The power noise detector is the modified circuit of frequency voltage converter. The proposed PLL has been designed based on a 1.8V 0.18um CMOS process and proved by HSPICE simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.512-518
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• 2003

Position controls are very important in semiconductor manufacturing devices, machine tools Precision measuring instruments, etc. To measure the distance of movement of moving objects in minute units and the accuracy of measurement for the moving distance in these devices affect the performance of the whole devices. Therefore, in those Precision instruments, a sensing device that can measure the distance of movement with high-precision resolution is required. In this paper, a novel encoder of digital and analog hybrid type is proposed. It is shown that from this experiment a high-resolution angle measurement device can be designed by a low cost incremental encoder.

• Journal of the Society of Disaster Information
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• v.8 no.1
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• pp.27-35
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• 2012

The main objective of this paper is to evaluate the field applications and the noise reductions of micro surfacing pavement, which is often used to reduce environmental problems. A traffic noise mechanism was analyzed and a modified mix design method was proposed for nighttime constructions. Results on noise measurements using the statistical pass-by method showed noise reductions of 2.0 to 7.1 dB were observed. In addition, results on noise measurements using the close proximity method demonstrated that noise reductions of 5.6 to 6.7 dB were recorded under vehicle speed of 80km/h. The noise measurements revealed that the close proximity method was more stable than the statistical pass-by method. As a result, the effect of micro surfacing pavement on noise reductions was proved through the research. It is considered that the micro surfacing pavement method could be used as a preventive maintenance method and a comfortable noise reducing pavement technique.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.71-76
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• 2000

The biological carbon dioxide fixation using microalgae has been known as an effective carbon dioxide reduction technology. With many environmental factors influencing microalgal productivity, the desirable cultivation factors were investigated using a green alga, Euglena gracilis. It has the high protein and vitamin E to be used as fodder. In batch culture with a photobioreactor, initial pH, temperature, carbon dioxide concentration and light intensity in the optimum cultivation condition were 3.5, $27^{\circ}C$,5-10% and $520{\mu}mol/m^2/s$, respectively. After that, the optimum hydraulic retention time (HRT for the continuous cultivation was 4 days at carbon dioxide concentration of 10%. In this condition, the final dry cell weight was 1.2g/l.

• The korean journal of orthodontics
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• v.37 no.1 s.120
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• pp.56-64
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• 2007

Objective: The purpose of this study was to evaluate the effects of malocclusion and orthodontic treatment on the self-esteem of adolescents. Methods: The subjects were composed of 3509 female middle school students. Each subject was evaluated with Rosenberg's Self-esteem Scale to measure the level of self-esteem and also evaluated the degree of crowding and soft tissue profile. Results: Results showed that protrusion of lip area had no effects on self-esteem but crowding of upper anterior teeth had significant effects. The fixed orthodontic treatment group and the removable orthodontic treatment group reported no significant difference in self-esteem from the no orthodontic treatment experience group, but the debonding group showed significantly higher Self-esteem index. Conclusion: The results of this study suggest that anterior teeth alignment has influence on the self-esteem of female adolescents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.2
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• pp.322-327
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• 1994

For the improvement of L-lysine productivity, development of the continuous fermentation system by a bioreactor assembly was attempted. Primarily, optimal conditions on the whole cell immobilization of Corynebacterium glutamicum ATCC21514 were studied and 76.2% of immobilization ratio was obtained when the cells were entrapped with 4% k-carrageenan showing 4.0kg gel strength. A bioreactor system was set up using the immobilized cells was applied for the continuous production of L-lysine. The results obtained under the optimum conditions were compared with those of the batchwise fermentation. Experimental results obtained from 14 day continuous fermentation showed 36.7% of sugar conversion to L-lysine while the productivity of L-lysine was disclosed as 4.96mg/ml mg-dry cell weight /hr which is 2.5times and 4.1 times higher than those of the batchwise fermentation by the intact cells and by the immobilized cells, respectively.

• KSBB Journal
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• v.5 no.2
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• pp.167-173
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• 1990

This study is to investigate for obtaining the operating conditions of continuous vinegar production using fluidized bed reactor by Acetobacter aceti cell immobilized in Ca-alginate gel. The optimum conditions obtaining by batch fermentation using fluidized bed reactor were as follows; The fermentation temperature and aeration rate were 3$0^{\circ}C$ and 1.0VVM and the initial concentration of ethanol and acetic acid in medium were 33g/l and 27g/l respectively. The amount of bead used was 25%(w/v). The overall acetic acid productivities of batch fermentations by free cell and immobilized cell were 0.31g/l-hr and 0.48g/l-hr, respectively, at the final acetic acid concentration of 50g/l. In the continuous vinegar production using fluidized bed reactor by immobilized cell under optimum conditions, it was possible to produce 23g/l acetic acid continuously up to 90 days with maximum acetic acid productivity of 2.76g/l-hr at dilution rate 0.12hr-1.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.2
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• pp.318-328
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• 1991

The present paper describes the experimental study on the fixed-type wave-energy conversion system, consisting of the OWC-type wave-energy absorbing chamber and the duct for the air turbine. For simplicity, a screen of wire mesh was employed in place of an air turbine in order to simulate its effects on OWC chamber. Experiments were performed at the towing tank in regular waves with the frequency range of 0.22-0.75Hz. Comparison wish the numerical prediction using a potential flow-based method [4] was made to validate the capability of numerical code. It was shown that the agreements between measured and calculated results are quite good, giving a confidence in prediction method. Simulation of air turbine using a wire-mesh screen was successful, at least in a qualitative sense, to investigate the inter action between the OWC chamber and an air turbine. Results also showed that the effects of a wire-mesh screen on chamber efficiency are negligible, and the present model can be effectively utilized for the practical use in ocean waves with the frequency range under 0.3Hz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.47-54
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• 2019

In the worldwide, The issue comes up which is the danger of car accidents from climate-change effects. We are considering about various types of speed limit signs for setting restricts to high-speed vehicles. South Korea has 4 seasons in the land. At Summer or Winter seasons have heavy rains and fogs or snow, In these seasons need to enforce speed limit laws or methods to prevent car collision. But South korea is using stationary speed limiters that is not enough to proof against rear-end car accidents in these climates. In this paper shows the necessity of independent LED speed limits display to reduce car accidents. And explaining the prototype model which is a combination of rain sensor and wiper systems. This model is independently changed the speed limits to 50%, 80%, 100% of standards by raindrops and snowflake. Also it is freely setting speed limits on each places anywhere it settled in. Visual effects of the model as being speed-down of vehicles helps to prevent rear-ending car accidents and traffic beforehand.

• Journal of Navigation and Port Research
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• v.32 no.3
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• pp.257-264
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• 2008

This study is intended to know what is the legal problems to settlement and public announcement of property right for construction of marine architectural building in Korea. Firstly, the situation and the prospect around marine architectural building are examined Secondly, the legal concepts of marine architectural building and the application of related laws are analyzed. Thirdly, the problems related to public announcement of property right of marine architectural building are suggested. Fourthly, some improvement schemes to solve the legal problems in relation with property right of buildings on the water at sea and ocean are proposed. As the conclusion, the marine architectural building can be divided into fixed-type and floating-type in order to find the proper way to handle the public announcement of property right for that sort of building. The fixed-typecan be registered as real estate according to the Building Law through the amendment of the existing related laws. But for the registration of floating-type building a new law should be made. In the near future, improvements on the legal system related with the settlement of property right of marine architectural building should be made, so that private sectors can join construction and operation of the building. Especially a new law for the floating-type marine architectural building should be made as soon as possible.