• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.143-143
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• 2011

4대강 살리기 사업에서 국가하천 주요 구간에 대규모 보가 건설되고 있다. 이로 인해 치수 및 하천환경에 많은 문제점이 야기될 수 있으며, 발생 가능한 하천관리의 문제점을 최소화하기 위해서는 하천정비에 따른 수리학적 영향을 검토할 필요가 있다. 보의 설치는 유지유량 및 수심 확보의 목적을 지니고 있지만, 기존 하천에 설치된 보는 대부분 고정보로서 흐름의 정체를 유발시키는 단점이 있다. 최근에는 가동보가 설치되어 일정 이상의 초과 유량 및 수위를 조절할 수 있도록 탄력적인 보 운영이 이루어지고 있다. 본 연구에서는 낙동강 본류에 건설 중인 강정보 설치지점 직상 하류 구간에 대하여 가동보의 설치 및 운영에 따른 보주변의 흐름특성을 RMA2와 FLOW-3D를 이용하여 모의하였다. 2개의 수문으로 구성되어 있는 강정보의 수문 운영을 2년 빈도 및 100년 빈도 홍수량에 대하여 좌측 또는 우측 단일수문 완전개방 및 부분개방, 양측 수문의 완전개방 및 부분개방에 따른 보 상류단 수위의 변화 및 하류단에 형성되는 주흐름의 변화를 분석하였다. 2년 빈도 홍수량에서의 가동보 지점의 유속이 100년 빈도 홍수량에 대한 가동보 지점의 유속보다 크게 발생하였다. 양측 수문을 완전히 개방하였을 때 주흐름이 우안방향으로 휘는 현상이 발생하였으며, 우측 수문 단일개방에서 주흐름의 우측 휨 현상이 뚜렷이 나타나고 있어 양측 수문 개방에서의 주흐름이 우측 수문에서 발생되는 흐름에 의해 지배되고 있는 것으로 판단된다. 100년 빈도 홍수량에 대한 모의에서 수문 개방방식에 따른 보 상류부의 홍수위 변화가 크게 나타나지 않았으며, 2년 빈도 홍수량에서는 수문 개방 방식에 대한 보상류의 수위가 차이를 보였다. 가동보의 $30^{\circ}\sim60^{\circ}$ 부분개방에 대한 모의결과에서는 부분개방의 정도가 커짐에 따라 수문 지점에서의 유속이 크게 발생하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.2032-2041
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• 1998

In this work, we propose a novel bit allocation method that is to minimize overall distortions subject ot the bit rate constraint. We partition the original bitallocation problem into 'macroblock level bit allocation' problems that can be solved by conventional Lagrangian mutiplier methods and a 'frame level bit allocation' problem. To tackle the frame level problem, 'two-phase optimization' algorithm is used with iter-frame dependency model. While the existing approaches are almost impossible to find the macroblock-unit result for the moving picture coding system due to high computational complexity, the proposed algorithm can drastically reduce the computational loads by the problem partitioning and can obtain the result close to the optimal solution. Because the optimally allocated results can be used as a benchmark for bit allocation methods, the upper performance limit, or a basis for approximation method development, we expect that the proposed algorithm can be very useful for the bit allocation related works.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.4
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• pp.340-348
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• 2006

This paper proposes an inrush current control technique of matching transformer for configuration of dynamic voltage restorer(DVR). The DVR system consist of PWM inverter to inject arbitrary voltage, LC low pass filter as harmonic eliminator and matching transformer for isolation. However, the matching transformer has an excess of inrush current by magnetic flux saturation in the core. Due to this inrush current, the rating of matching transformers is double for needed nominal rating for protection of DVR. Therefore, in this paper, the modeling method of magnetic flux saturation is used to analyze a magnitude of inrush current, and additional current controller is used for PWM inverter output regulation. Simulation and experimental results are provided to demonstrate the validity of the proposed control method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2C
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• pp.77-84
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• 2010

In planning underground roadway foundation on soft ground, deep cement mixing method (DCM) is employed. The proper mixing ratio using batch test and replacement rates that meet strength criteria are used for deep cement mixing column. Stiffness ratio and distance between deep cement mixing columns (C.T.C) are varied to find out influences on stress, displacement, and differential settlement. The replacement ratios that meet settlement criteria are 10~35%. As stiffness varies, stress reaches at 769.kPa that exceed criteria due to stress concentration when stiffness ratio difference is over 30. Also, when C.T.C is 5 m, stress spreads to soils, so C.T.C need to be considered carefully. The vertical displacement is 0.6~1.56 cm, and angular distortion is 1/909~1/510.

• Journal of Environmental Policy
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• v.7 no.3
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• pp.89-120
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• 2008

With petroleum being a major source of energy in Korea, the quantity of petroleum transported via ocean routes is on its way up due to increased consumption. Due to the increase, more than 300 cases of pollution caused by petroleum occur annually. Moreover, the number of oil-spill accidents is also on the rise. Causes of such accidents, not including the disposal of waste oil on purpose, turn out to be human error during navigation or defects in the vessels, showing that most accidents are caused by humans. Therefore, to prevent future oil spills, it is imperative that navigation efficiency be enhanced by improving the quality of navigators and replacing old vessels with newer ones. Nevertheless, such improvements cannot occur overnight, so long- and mid-term efforts should be made to achieve it institutionally. As large-scale oil-spill accidents can happen at anytime along the coastal waters of Korea, it is necessary to set-up institutional devices which go beyond the compensation limit of 92FC. The current special law regarding this issue has its limits in that it prescribes compensation be supplemented solely by national taxes. Therefore, the setting-up of a new 'national fund' is recommended for consideration rather than to subscribe to the '2003 Convention for the Supplementary Fund'. It is strongly suggested that a National fund be created from fees collected from oil companies based on the risks involved in oil transportation and according to the profiteers pay principle. In addition, a public fund should be created to handle general environmental damage, such as the large-scale destruction of the ecosystem, which is distinct from the economic damage that harms the local people. The posterior responses to the large-scale oil spill have always been unsatisfactory because of the symbolic nature of the disasters included in such accidents. Oil-spills can be prevented in advance, because they are caused by human beings. But once they occur, they inflict long-term damage to both human life and the natural ecosystem. Therefore, the best response to future oil-spills is to work to prevent them.

• Management & Information Systems Review
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• v.29 no.1
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• pp.1-23
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• 2010

This study examines the impacts of outside directors' characteristics and compensation on stock performances of KOSDAQ and NASDAQ IPO firms. The results of this study indicated the following interesting results. First, there is no significant relation between outside directors' age and CARs on KOSDAQ firms. while significant positive relation between outside directors' age and CARs on NASDAQ firms. And the elder age group shows a more positive impact on performances compared with the younger age group. Second, there is no relation between outside directors' academic background and CARs for KOSDAQ firms. But We find a significantly positive one for NASDAQ firms. Third, In Relation to outside directors' careers, their professional or CEO careers group have more positive impact on stock performances than gray directors' careers group. Lastly, there is an insignificant negative relation between the outside directors' compensation and CARs for KOSDAQ firms. while there is a positive relative for NASDAQ firms. In particular, there is a significant positive relative between value of stock options and CARs for NASDAQ firms. from the result, I could find out the stock option for outside' directors have a positive influence on firm value.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.3 s.309
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• pp.25-33
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• 2006

This paper proposed device-independent color matching algorithm based on the 3D RGB lookup table (LUT) between mobile camera and mobile LCD (Liquid Crystal Display) to improve the color-fidelity. Proposed algorithm is composed of thee steps, which is device characterization, gamut mapping, 3D RGB-LUT design. First, the characterization of mobile LCD is executed using the sigmoidal function, different from conventional method such as GOG (Gain Offset Gamma) and S-curve modeling, based on the observation of electro-optical transfer function of mobile LCD. Next, mobile camera characterization is conducted by fitting the digital value of GretagColor chart captured under the daylight environment (D65) and tristimulus values (CIELAB) using the polynomial regression. However, the CIELAB values estimated by polynomial regression exceed the maximum boundary of the CIELAB color space. Therefore, these values are corrected by linear compression of the lightness and chroma. Finally, gamut mapping is used to overcome the gamut difference between mobile camera and moible LCD. To implement the real-time processing, 3D RGB-LUT is designed based on the 3D RGB-LUT and its performance is evaluated and compared with conventional method.

• Information Systems Review
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• v.9 no.1
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• pp.191-214
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• 2007

This study analyzes the process of establishing BSC based strategic performance evaluation system of KOMSCO. This case could be a reference to other public institutes for BSC introduction and efficient BSC usage. Internal control system of KOMSCO has been improved by EVA system in 1999, BSC introduction and Job analysis in 2001 through 2002, and BSC performance evaluation system in 2004. KOMSCO tries to reflect BSC concept by inducing employees to cooperate selection process of CSF and KPI and by considering the organizational characteristics of KOMSCO in constructing it's performance indices. It is suggested that these processes are very important and should be followed by other institutes in their BSC introduction. By applying BSC, KOMSCO provides improvement in employees' understanding of strategy, performance management, and performance evaluation. KOMSCO' information system based on ERP and efficiently connected to EIS, KMS, and BSC seems to play an important role of BSC application. BSC system of KOMSCO is now in the early stage of application and needs to be evaluated by the efficiency of usage in terms of overall performance evaluation system, deduction system of evaluation point for excess accomplishment over target, and connection to budget system.

• Horticultural Science & Technology
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• v.18 no.1
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• pp.22-27
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• 2000

National plant quarantine inspector of exporting country should inspect agricultural products according to the quarantine requisites of counterpart country when the commodities are shipped. Export of pear fruits was held because quarantine pests including Conogethes punctiferalis were found at the point of entry in Canada. In order to examine the problems in detail, the inspected pear fruits were stored at a low temperature for 43 days, almost the same period necessary for fruit sorting, quarantine procedures, and transportation by ship. Dead larvae of fruit moths, C. punctiferalis and Grapholita molesta were found during cold storage. Quarantine pathogens were not found, but non-quarantine ones such as Penicillium sp. was infected through wounds by bruises and stabs resulted from sorting procedures. Because of the wounding problem during export procedures, pear fruits with thin exocarp, such as fruits of P. pyrifolia Nakai cv. Whangkeumbae, are required more careful handling during fruit sorting and conveyance.

• Journal of Venture Innovation
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• v.5 no.3
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• pp.57-70
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• 2022

In modern industrial capitalism, the relationship between the provision of work and the receipt of wages has become an important principle governing society. According to the labor contract, the wages provided by entrusting the right to dispose of one's labor to the employer are directly compensated, and human life should be guaranteed and reproduced with proper rest. The establishment of labor relations under free contracts represents a problem in protecting workers, and accordingly, the maximum of working hours is set as a minimum right for workers, and the standard for minimum rest is set and assigned. The reduction of working hours is very important in terms of the quality of life of workers, but it is also an important issue in efficient corporate activities. As of 2020, Korea has 1,908 hours of annual working hours, the third lowest among OECD 37 countries in the happiness index surveyed by the Sustainable Development Solution Network(SDSN), an agency under the United Nations. Accordingly, the necessity of reducing working hours has been recognized, and the maximum working hours per week has been limited to 52 hours since 2018. In this situation, various working hours are legally excluded as a way to maintain the company's value-added creation and meet the diverse needs of workers, and Korea's Labor Standards Act restricts flexible working hours within three months, flexible working hours exceeding three months, selective working hours, and extended working hours. However, in the discussion on the application of the revised flexible working hours system in 2021 and the expansion of the settlement unit period recently discussed, there is a problem with the flexible working hours system, which needs to be improved. Therefore, this paper aims to examine the problems of the flexible working hours system and improvement measures. The flexible working hours system is a system that does not violate working hours even if the legal working hours are exceeded on a specific day or week according to a predetermined standard, and does not have to pay additional wages for excessive overtime work. It is mainly useful as a form of shift work in manufacturing, sales service, continuous business or electricity, gas, water, and transportation for long-term operations. It is also used as a way to shorten working hours, such as expanding holidays through short working days. However, if the settlement unit period is expanded, it is disadvantageous to workers as the additional wages that workers can receive will not be received. Therefore, First, in order to expand the settlement unit period currently under discussion, additional wages should be paid for the period expanded from the current standard. Second, it is necessary to improve the application of the flexible working hours system to individual workers to have sufficient consultation with individual workers in a written agreement with the worker representative, Third, clarify the allowable time for extended work during the settlement unit period, and Fourth, limit the daily working hours or apply to continuous rest. In addition, since the written agreement of the worker representative is an important issue in the application of the flexible working hours system, it is necessary to secure the representation of the worker representative.