• Journal of Radiation Protection and Research
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• 제42권3호
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• pp.141-145
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• 2017

Background: The concrete walls inside the vaults of cyclotron facilities are activated by neutrons emitted by the targets during radioisotope production. Reducing the amount of radioactive waste created in such facilities is very important in case they are decommissioned. Thus, we proposed a strategy of reducing the neutron activation of the concrete walls in cyclotrons during operation. Materials and Methods: A polyethylene plate and B-doped Al sheet (30 wt% of B and 2.5 mm in thickness) were placed in front of the wall in the cyclotron room of a radioisotope production facility for pharmaceutical use. The target was Xe gas, and a Cu block was utilized for proton dumping. The irradiation time, proton energy, and beam current were 8 hours, 30 MeV, and $125{\mu}A$, respectively. To determine a suitable thickness for the polyethylene plate set in front of the B-doped Al sheet, the neutron-reducing effects achieved by inserting such sheets at several depths within polyethylene plate stacks were evaluated. The neutron fluence was monitored using an activation detector and 20-g on de Au foil samples with and without 0.5-mm-thick Cd foil. Each Au foil sample was pasted onto the center of a polyethylene plate and B-doped Al sheet, and the absolute activity of one Au foil sample was measured as a standard using a Ge detector. The resulting relative activities were obtained by calculating the ratio of the photostimulated luminescence of each foil sample to that of the standard Au foil. Results and Discussion: When the combination of a 4-cm-thick polyethylene plate and B-doped Al sheet was employed, the thermal neutron rate was reduced by 78%. Conclusion: The combination of a 4-cm-thick polyethylene plate and B-doped Al sheet effectively reduced the neutron activation of the investigated concrete wall.

• 천문학회보
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• 제41권1호
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• pp.54.2-54.2
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• 2016

Korea Microlensing Telescope Network (KMTNet) is the first optical survey system of its kind in a way that three KMTNet observatories are longitudinally well-separated, and thus have the benefit of 24-hour continuous monitoring of the southern sky. The wide-field and round-the-clock operation capabilities of this network facility are ideal for survey and the physical characterization of small Solar System bodies. We obtain their orbits, absolute magnitudes (H), three dimensional shape models, spin periods and spin states, activity levels based on the time-series broadband photometry. Their approximate surface mineralogy is also identified using colors and band slopes. The automated observation scheduler, the data pipeline, the dedicated computing facility, related research activity and the team members are collectively called 'DEEP-South' (DEep Ecliptic Patrol of Southern sky). DEEP-South observation is being made during the off-season for exoplanet search, yet part of the telescope time is shared in the period between when the Galactic bulge rises early in the morning and sets early in the evening. We present here the observation mode, strategy, software, test runs, early results, and the future plan of DEEP-South.

• 한국주거학회논문집
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• 제23권1호
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• pp.27-41
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• 2012

The objective of this study is to develop the blind control strategy and method which reduce negative effect of incoming daylight on visual comfort of occupants, minimize psychological anxieties caused by frequent motions of a blind, and maximize positive effect of incoming daylight and solar irradiation by opening/closing of a blind. As previous researches on blind controls have limited outdoor environmental conditions to those in specific regions, orientations and dates, these resulted in problems at various conditions for general-purpose application. Major problem is that the time interval and amount of blind movement do not meet the control objective at the end of control zone and discontinuous curve. To overcome these limitations revealed in the previous researches, following tasks were performed in this study. 1) To establish the control objective to accomplish the goal of this study. 2) To develop the control methods and algorithms which prevent glare on the work-plane at any time and which control the time interval and amount of blind movement to follow the control objective at various profile angle curves. 3) To validate the general-purpose applicability and performance of the developed control methods and algorithms by simulation and its data analysis at various conditions. It was found that the proposed methods and algorithms can prevent the direct glare on the work-plane at all the time and also increase the incoming daylight and solar irradiation.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 추계학술대회
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• pp.5-6
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• 2015

IMO 마리타임 클라우드는 이내비게이션의 실행전략으로서 연구, 개발 중인 기술이다. 마리타임 클라우드의 개발은 해양 이해관계자들 간의 안전하고 신뢰성 있는 정보 교환을 가능하게 한다. 본 논문에서는 이내비게이션 응용 서비스 설계 및 개발을 위해 오픈소스 기반의 마리타임 클라우드를 정적 분석하였다. 마리타임 클라우드의 핵심 기술 중 하나인 MMS의 컴포넌트 구성과 역할, 기능을 분석하고, 마리타임 클라우드 기반의 응용을 이해하기 위해 EPD 적용사례를 분석하였다. 마리타임 클라우드와 클라이언트 간의 동작과정 및 관계에 대한 분석결과는 향후 이내비게이션 서비스를 개발에 활용할 수 있다.

• 산업공학
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• 제23권4호
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• pp.311-318
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• 2010

In the daily multi-reservoir operating problem, monthly storage targets can be used as principal operational guidelines. In this study, we tested the use of a simple back-propagation Artificial Neural Network (ANN) model to derive monthly storage guideline for daily Coordinated Multi-reservoir Operating Model (CoMOM) of the Han-River basin. This approach is based on the belief that the optimum solution of the daily CoMOM has a good performance, and the ANN model trained with the results of daily CoMOM would produce effective monthly operating guidelines. The optimum results of daily CoMOM is used as the training set for the back-propagation ANN model, which is designed to derive monthly reservoir storage targets in the basin. For the input patterns of the ANN model, we adopted the ratios of initial storage of each dam to the storage of Paldang dam, ratios of monthly expected inflow of each dam to the total inflow of the whole basin, ratios of monthly demand at each dam to the total demand of the whole basin, ratio of total storage of the whole basin to the active storage of Paldang dam, and the ratio of total inflow of the whole basin to the active storage of the whole basin. And the output pattern of ANN model is the optimal final storages that are generated by the daily CoMOM. Then, we analyzed the performance of the ANN model by using a real-time simulation procedure for the multi-reservoir system of the Han-river basin, assuming that historical inflows from October 1st, 2004 to June 30th, 2007 (except July, August, September) were occurred. The simulation results showed that by utilizing the monthly storage target provided by the ANN model, we could reduce the spillages, increase hydropower generation, and secure more water at the end of the planning horizon compared to the historical records.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.648-658
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• 2018

Regarding the fact that wind power forecast accuracy is gradually improved as time is approaching, this paper proposes a two-stage rolling dispatch approach based on model predictive control (MPC), which contains an intra-day rolling optimal scheme and a real-time rolling base point tracing scheme. The scheduled output of the intra-day rolling scheme is set as the reference output, and the real-time rolling scheme is based on MPC which includes the leading rolling optimization and lagging feedback correction strategy. On the basis of the latest measured thermal unit output feedback, the closed-loop optimization is formed to correct the power deviation timely, making the unit output smoother, thus reducing the costs of power adjustment and promoting wind power accommodation. We adopt chance constraint to describe forecasts uncertainty. Then for reflecting the increasing prediction precision as well as the power dispatcher's rising expected satisfaction degree with reliable system operation, we set the confidence level of reserve constraints at different timescales as the incremental vector. The expectation of up/down reserve shortage is proposed to assess the adequacy of the upward/downward reserve. The studies executed on the modified IEEE RTS system demonstrate the effectiveness of the proposed approach.

• 전력전자학회논문지
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• 제20권6호
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• pp.550-557
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• 2015

The Jeju Special Self-Governing Province is currently promoting the "Carbon-free Island by 2030" policy, which requires the use of renewable energy instead of fossil fuel so that the island will have no carbon gases generated by 2030. To implement this policy, the island plans to build a wind power plant capacity of 1.09 GW in 2020; this wind power plant is currently ongoing. However, when wind power output is greater than the power demand of the island, the stability of Jeju Island power system must be prepared for it because it can be a problem. Therefore, this study proposes a voltage source-type MMC-HVDC system linked to mainland Korea to expand the wind power penetration limits of Jeju Island under the stable operation of the Jeju Island power system. To verify the effectiveness of the proposed scheme, computer simulations using the PSCAD/EMTDC program are conducted, and the results are demonstrated. The scenarios of the computer simulation consist of two cases. First, the MMC-HVDC system is operated under variable wind power in the Jeju Island power system. Second, it is operated under the predicted Jeju Island power system in 2020.

• 수산경영론집
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• 제36권3호
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• pp.37-63
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• 2005

According to the Fisheries Cooperative Law, the Fisheries Cooperative has made a substantial contribution to the development of Korea's fisheries industry amid the nation's rapid economic growth and drastic social changes since its establishment in April 1st 1962, It is, however, generally believed that the cooperative has made a poor performance in improving its business constitution. Therefore, the reform of its board of director system is one of the ways to strengthen the constitution. For the purpose of making the board of director system to operate rationally, this dissertation is divided into five chapters. Chapter I provides an overview of this study, such as research background and objectives. Chapter II focuses on the Fisheries Cooperative's board of director: its function, composition, and election. Chapter III analyzes the responses of the Fisheries cooperatives to questionnaires about the board of director system, and subsequently presents the causes and the meaning of the analysis results. Chapter IV deals with the various ways to improve the Fisheries Cooperative's board of director system, including director and cooperative governance. Finally, Chapter V draws a conclusion of this study. The independent function of the Cooperative's board of director and responsible directorship is one of the most important factors which can prevent the Cooperative from insolvency. Unlike the past, not only it has become difficult to keep the Cooperative's business under the government's support, but also the Cooperative itself is now facing a situation where the support from the government cannot be expected. This ist he reason why the Cooperative should manage itself autonomously, workout its organization, and respond to the current situation with a renovativemanagement and business strategy. Therefore, a rational operation of the board of director is urgently needed.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.644-651
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on water quality such as turbidity, temperature, pH and alkalinity. However, the process of chemical reaction to improve water quality (e.g., turbidity) by chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts using Jar-test data. In this paper, a systematic control strategy is proposed to derive the optimum dosage of coagulant, PAC(Polymerized Aluminium Chloride), using Jar-test results. A neural network model is developed for coagulant dosing and purifying process by means of six input variables (turbidity, temperature, pH, alkalinity of raw water, PAC feed rate, turbidity in flocculation) and one output variable, while considering the relationships to the reaction of coagulation and flocculation. The model is utilized to derive the optimum coagulant dosage (in the sense of minimizing turbidity of water in flocculator). The ability of the proposed control scheme validated through the field test has proved to be of considerable practical value.

• 디지털융복합연구
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• 제9권3호
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• pp.59-67
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• 2011

세계 항공산업은 디지털 기술의 발전과 더불어 지속적으로 성장하고 있다. 김포지역의 항공전자 시스템을 기반으로 하는 디지털 항공산업 발전방안을 수요적 측면, 제도적 측면, 산업구조적 측면에서 연구 하였다. 항공산업의 성장동력화를 위한 추진전략을 제시하고 전략 달성을 위하여 항공수요의 지속적 창출, 핵심 부품소재 육성 및 경쟁우위 디지털 기술력 확보, 제도 운용의 활성화를 위한 인프라 구축, 행정지원제도의 개선, 민 산 군 학 관의 정책조정기능 강화를 추진과제로 제안하였다. 연구를 수행한 결과 행정적, 산업적인 분야에서 관련 제도 등을 보완하면 항공정비산업과 헬기산업을 중심으로 김포지역의 디지털항공산업 발전이 가능하다는 결론을 도출 하였다.