• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.599-604
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• 1997

One of important inconsistencies in the six-equation model predictions has been found to be the force experienced by a single bubble placed in a convergent stream of liquid. Various sets of governing equations yield different amount of forces to hold the bubble stationary in a convergent nozzle. By using the first order potential flow theory, it is found that the six-equation model can not be used to estimate the force experienced by a deformed bubble. The theoretical value of the particle stress of a bubble in a convergent nozzle flow has been found to be a function of the Weber number when bubble distortion is allowed. This force has been calculated by using different sets of governing equations and compared with the theoretical value. It is suggested in this study that the bubble size distribution function can be used to remove the presented inconsistency by relating the interfacial variables with different moments of the bubble size distribution function. This study also shows that the inconsistencies in the thermal-hydraulic governing equation can be removed by mechanistic modeling of the phasic interface.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.314-317
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• 2002

This paper present a methods for performance evaluation of digital governor and we treat the way to reduce the trial and error when the developed digital governing system is applied to station. The parameters of the model are estimated using input-output data, the model adjustment technique and a genetic algorithm(GA). To verify validity of the completed model, the comparision model and real output signals have been carried out. The developed digital governing system is applied to Sumjingang hydro-power plant, Korea Hydro Nuclear Power Corporation, it has replaced mechanical governing system. Test was performed in order to demonstrate the performance evaluation of the digital governor parameters.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.2011-2015
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• 2009

In an insulating dielectric liquid such as transformer oil, space charge injection and propagation were analyzed under the Fowler-Nordheim and Richardson-Dushman's thermal emission charge injection conditions for blade-plane electrodes stressed by a step voltage. The governing equations were composed of all five equations such as the Poisson's equation for electric fields, three continuity equations for electrons, negative, and positive ions, and energy balanced equation for temperature distributions. The governing equations for each carrier, the continuity equations, belong to the hyperbolic-type PDE of which the solution has a step change at the space charge front resulting in numerical instabilities. To decrease these instabilities, the governing equations were solved simultaneously by the Finite Element Method (FEM) employing the artificial diffusion scheme as a stabilization technique. Additionally, the terminal current was calculated by using the generalized energy method which is based on the Poynting's theorem, and represents more reliable and stable approach for evaluating discharge current. To verify the proposed method, the discharge phenomena were successfully applied to the blade~plane electrodes, where the radius of blade cap was $50{\mu}m$.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.5
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• pp.351-365
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• 2021

Water treatment process simulator is the tool for predicting sequential changes of water quality in a train of unit processes. This predicts the changes through governing equations that represent physicochemical performance of each unit processes with an initial and boundary conditions. Since there is no operational data for the design of a water treatment facility, there is no choice but to predict the performance of the facility by assuming initial and boundary conditions in virtual reality. Therefore, a simulator that can be applied in the design stage of a water treatment facility has no choice but to be built as a numerical analysis model of a deductive technique. In this study, we had conducted basic research on governing equations, inter-process data-flow, and simulator algorithms for the development of simulators. Lastly, this study will contribute to design engineering tool development research in the future by establishing the water treatment theory so that it can be programmed in a virtual world and suggesting a method for digital transformation of the water treatment process.

• Korea Trade Review
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• v.44 no.6
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• pp.1-21
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• 2019

In the case of a sea transport contract, the decision of the governing law, together with the choice of lex fori, shall be a legal issue in all legal disputes involving damage to the goods. In sea transport contracts, a paramount clause is often established in conjunction with the governing law clause, which can lead to conflict between these two clauses. Most B/L's back clauses contain a paramount clause that provides that the Hague Rules, Hague-Visby Rules, or foreign laws that prevail over other provisions of the terms. The Hague Rules and the Hague-Visby Rules, however, set different standards regarding the extent of the sea carrier's liability. Therefore, in the interpretation of ground conditions, it is an important question whether the Hague Rules or the Hague-Visby Rules are applied or whether each rule is applied as a law. For example, the paramount clause in the Superior Pescadores case was problematic in the interpretation of the term 'Hague Rules.' In this case, the English Court held that the expression 'Hague Rules' could be used to mean the Hague-Visby Rules, and not exclusively the Hague Rules. Therefore, the Hague-Visby Rules were applied in the judgment of this case, which suggests that this case can be a valuable precedent in future legal matters.

• Structural Engineering and Mechanics
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• v.76 no.6
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• pp.765-779
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• 2020

This article presents a nonclassical size dependent model based on the modified couple stress theory to study and analyze the bending behavior of perforated microbeams under different loading patterns. Modified equivalent material and geometrical parameters for perforated beam are presented. The modified couple stress theory with one material length scale parameter is adopted to incorporate the microstructure effect into the governing equations of perforated beam structure. The governing equilibrium equations of the perforated Timoshenko as well as the perforated Euler Bernoulli are developed based on the potential energy minimization principle. The Poisson's effect is included in the governing equilibrium equations. Regular square perforation configuration is considered. Based on Fourier series expansion, closed forms for the bending deflection and the rotational displacements are obtained for simply supported perforated microbeams. The proposed methodology is validated and compared with the available results in the literature and an excellent agreement is detected. Numerical results demonstrated the applicability of the proposed methodology to investigate the bending behavior of regularly squared perforated beams incorporating microstructure effect under different excitation patterns. The obtained results are significantly important for the design and production of perforated microbeam structures.

• Journal of Environmental Science International
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• v.30 no.8
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• pp.647-658
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• 2021

Jeju Special Self-Governing Province has implemented a self-governing environmental impact assessment system (Jeju-EIAS) in recognition of its autonomy. In this study, the institutional features of Jeju-EIAS were examined by analyzing the development projects whose consultation under Jeju-EIAS were completed from 1994 to 2019. The consultation procedure of Jeju-EIAS, such as the actual operation of Review Committee for Environmental Impact Assessment (EIA), the consent of the provincial council, and the regular follow-up activities for the implementation of EIA consultations, has been implemented differently from those of other metropolitan cities and provinces. Under Jeju-EIAS, types of development projects subject to consultation on EIA also take into account local conditions, and include the construction of aquarium basin and building. In addition, provisions concerning the scale of development projects is strengthened above the Korean Environmental Impact Assessment Act (EIA Act).

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.497-505
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• 2021

This paper investigates the current status of Jeju special self-governing province (JSSGP)'s water infrastructure and recommends directions for improvement. JSSGP relies on groundwater for most of its water resources. Recently, water usage has been steadily increasing due to the increase of residents and tourists while the quality of groundwater has been steadily worsening. Deterioration in water quality of groundwater can be seen through the increase in concentration of nitrate nitrogen and microorganisms. To overcome such problems, water consumption must be reduced by water demand management in all fields including residential and agricultural water use. The quality of water resources should be preserved through the management of pollutants. For efficient management of water resources, great efforts should be made to reduce the leakage rates in household and agricultural water, which is currently at the highest level in the country. Furthermore, diversification of water intake sources other than groundwater is needed, especially for agricultural water supply. For water and sewerage facilities, compliance with drinking water quality standards and discharge water quality standards must be achieved through the optimization of operation management. This process requires recruiting professionals, improving existing workers' expertise, and improving facilities.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.2
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• pp.126-131
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• 2017

To improve the efficiency of hairtail trolling, it is important to gain an accurate understanding of the distribution of fish based on their diurnal vertical migration patterns. This study evaluated the vertical distribution of hairtails through catch efficiency tests using vertical longlines. Five replicate tests of the efficiency were carried out on the eastern coast of Jeju Island from August to September 2016, from 11:00 AM to 03:00 PM in the daytime and 11:00 PM to 03:00 AM in the nighttime. The fishing gear was composed of 20 hooks per line set, numbered in order from the first hook near the surface to the last hook on the seabed. The depth of the first hook was 18 m, and that of the last hook was 86 m. Pacific saury was used as the baits. In total, 10 sets of fishing gear were used per trip. After fishing, we counted the hairtails at each numbered hook, which were summed up both by number and in aggregate. A total of 232 hairtails were caught using 2,000 hooks: 193 individuals at daytime and 39 at nighttime. The hook rate was 11.5% : 9.6% at daytime; 2.0% at nighttime. For both daytime and nighttime catches, there were variations in the hook rates at each numbered hook. In the daytime, a maximum of 28.5% catches occurred at hook number 18, followed by 21.4% at number 20, and 10.7% at number 17, accounting for 60.6% of the daytime hook rates. In the nighttime, a maximum of 23.0% catches occurred at hook number 1, followed by 15.3% at hook number 4 and 9, accounting for 53.6% of the nighttime hook rate. Based on the above results, hairtails are usually distributed in deeper region in daytime, whereas they occur near the surface in nighttime. Therefore, it is necessary to position trolling lines according to diurnal vertical distribution layers of hairtails for fishing efficiency.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.12
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• pp.461-494
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• 1999

This study is to analyse the applicability of governing law in multi-party contractual relationship of letter of credit. And this study is also to suggest the limits of the possibility of applicable law in multi-party contract. The contract of letter of credit constitutes complex relationship, i.e., applicant -beneficiary, applicant-issuing bank, issuing bank-intermediary bank ect. The law applicable to letter of credit should not use a singular governing law in all credit transaction as sales contract. To solve these problems, the author analysed the law applicable to the credit under multi-party contractual relationship as follow : (1) the principle of party autonomy (2) In the absence of express agreement with regard to the law applicable to the contract, lex loci contractus, lex loci solutionis, the law intended by the parties, the law with which contract is most closely connected. Accordingly, when attempting to ascertain the law governing the credit, it should be borne in mind that the credit involves several contractual relationships. I would like to conclude as follows: 1. The contract between the applicant and the Issuing bank is to be governed by the law of the country where the contract is made, and in which the bank carries on business and has issued the credit. 2. When it comes to the beneficiary-Intermediary bank relationship the following rule is given : The liability of an intermediary bank to the seller is governed by the law the country where the intermediary bank is operating if it is acting as principal. If, however, it is acting as agent(advising bank), it will be the law of the country where his principal is situate. 3. The contract between the beneficiary and the Issuing bank is governed by the law of the country where the payment is to be performed. 4. The contract between the Issuing bank and Intermediary bank is governed by 1) the law of the issuing bank is applicable if the intermediary bank only advises the credit, 2) the law of the issuing bank is applicable but if the intermediary bank makes payment, accepts or negotiates drafts against the tender of the documents, i.e., act as the bank dffecting the payment., 3) the law of the confirming bank is applicable if the irrevocable letter of credit is confirmed by the intermediary bank