• Journal of Radiation Protection and Research
• /
• v.28 no.2
• /
• pp.127-135
• /
• 2003

The primary contributors to the total occupational radiation exposure in operating nuclear power plants are operation and maintenance activities doting refueling outages. The Advanced Power Reactor 1400 (APR1400) includes a number of design improvements and plans to utilize advanced maintenance methods and robotics to minimize the annual collective dose. The major radiation exposure reduction features implemented in APR1400 are a permanent refueling pool seal, quick opening transfer tube blind flange, improved hydrogen peroxide injection at shutdown, improved permanent steam generator work platforms, and more effective temporary shielding. The estimated average annual occupational radiation exposure for APR1400 based on the reference plant experience and an engineering judgment is determined to be in the order of 0.4 man-Sv, which is well within the design goal of 1 man-Sv. The basis of this average annual occupational radiation exposure estimation is an eighteen (18) month fuel cycle with maintenance performed to steam generators and reactor coolant pumps during refueling outage. The outage duration is assumed to be 28 days. The outage work is to be performed on a 24 hour per day basis, seven (7) days a week with overlapping twelve (12) hour work shifts. The occupational radiation exposure for APR1400 is also determined by an alternate method which consists of estimating radiation exposures expected for the major activities during the refueling outage. The major outage activities that cause the majority of the total radiation exposure during refueling outage such as fuel handling, reactor coolant pump maintenance, steam generator inspection and maintenance, reactor vessel head area maintenance, decontamination, and ICI & instrumentation maintenance activities are evaluated at a task level. The calculated value using this method is in close agreement with the value of 0.4 man-Sv, that has been determined based on the experience aid engineering judgement. Therefore, with the As Low As Reasonably Achievable (ALARA) advanced design features incorporated in the design, APR1400 design is to meet its design goal with sufficient margin, that is, more than a factor of two (2), if operated on art eighteen (18) month fuel cycle.

• Journal of the Korean Solar Energy Society
• /
• v.39 no.6
• /
• pp.113-125
• /
• 2019

With the opening of the small power brokerage business market in December 2018, the small power trading market has started in Korea. Operators must submit the day-ahead estimates of power output and receive incentives based on its accuracy. Therefore, the accuracy of power generation forecasts is directly affects profits of the operators. The forecasting process for power generation can be divided into two procedure. The first is to forecast solar irradiation and the second is to transform forecasted solar irradiation into power generation. There are two methods for transformation. One is to simulate with physical model, and another is to use regression model. In this study, we found the best-fit regression model by analyzing hourly data of PV output and solar irradiation data during three years for 242 PV plants in Korea. The best model was not a linear model, but a sigmoidal model and specifically a Gompertz model. The combined linear regression and Gompertz curve was proposed because a the curve has non-zero y-intercept. As the result, R² and RMSE between observed data and the curve was significantly reduced.

• Journal of the Korea Furniture Society
• /
• v.23 no.4
• /
• pp.415-424
• /
• 2012

Since the Korean War, starvation and severly desperate living conditions hit the whole country. However, Koreans finally overcame such difficulties, achieving the miracle on the Han River. Through rapid industrial developments, Korea would not need any more supports from the outside but rather became a country which would offer a support. Meanwhile, in 1997, the Korean domestic economy underwent IMF which had caused a massive number of unemployeds. Among those people, many began to show interest in D.I.Y woodcraft for a whole new change and eventually, the industry of D.I.Y woodcraft business became expanded. Now, Korea survived I.M.F and was grown as one of the leading countries in the world, having held the G20 summit conference. Such achievements helped national income increased with the domestic GNP of $30,000, having exceeded $20,000. The population also grew to over fifty million and with all these factors, Korea joined the ranks of advanced countries. As a living environment of an individual gets improved and people have had time on their sides due to the five-day workweek, many have been taking this opportunity to engage in self-development and leisure activities. As trends are pursuing eco-friendliness and D.I.Y, D.I.Y woodcraft workshops are opening nationwide. Considering this, as analyzing present conditions of D.I.Y woodcraft workshops, which are being quickly popular at this moment in Korea, this study focuses on presenting a Korean-style D.I.Y woodcraft workshop, suggesting how to promote D.I.Y woodcraft business to be a pivot of the furniture industry in Korea.

• Development and Reproduction
• /
• v.24 no.3
• /
• pp.159-165
• /
• 2020

Previously, we reported adverse effects of low-dose nonylphenol (NP) exposure on the reproductive parameters of F1 female mice. In the present study we further investigated the pathohistological effect of NP exposure on the reproductive organs in F1 female mice. NP exposures were continuously conducted from parental pre-mating period until the postnatal day (PND) 33 of F1 offspring for vaginal examination. Mice were sacrificed on PND 30 and the reproductive tissue weights were measured. The initial (at PND 21) body weights of the NP-50 group animals were significantly lower than those of control group animals, and the weight deficit were recovered when the terminal (PND 33) body weights were measured. Early vaginal opening was found in NP group animals (p<0.05). Pathohistological studies revealed that NP-treated F1 animals showed prominent increase in the ovarian follicle numbers (p<0.01), and decrease in the diameter of uterine myometrium (p<0.01), and increase in the diameter of luminal epithelium (p<0.05). The present study demonstrated that the subchronic low-dose NP exposure induced early beginning of puberty and pathohistological abnormalities in ovary and uterus of F1 mice. Further studies are needed to achieve a better understanding on the action mechanism of NP in pubertal onset and to find a way to avoid a hazardous situation provoked by NP exposure.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.7
• /
• pp.1069-1076
• /
• 2012

We use largely two methods, how to control the noise of the KTX, they are the passive noise control method and the active noise control method. The passive noise control has been used in a variety of ways since the KTX opening day, but lately it has shown the technical limitations by being dropped sharply. So, it is getting important to conduct the research about ANC that is able to reduce the ambient noise when the environmental-factor changes and be installed easily. To reduce a three-dimensional closed-space sound field like a car of a high-speed rail is hard to do using single channel ANC control system. Therefore we have to model the paths of the noise exactly for reducing the noise. And the control speakers and the error mics should be designed for optimal position. In this paper, we designed the transfer functions for modeling the noise paths under the influence of the distance between control speakers & error mics and primary noise speaker in TEST-BED where there is modeled as actual interior of KTX. We have made the modeling and the simulations of interior environment of KTX car by using three frequency bands of 120Hz, 280Hz, 360Hz. After the modeling, we compared the performance of active noise control and also we analyzed what to affect with difference in distance. After comparing of the performance using Pure Tone 120Hz, 280Hz, 360Hz at each modeling and then we simulated ANC for KTX's interior noise which we measured really and analyzed.

• KEPCO Journal on Electric Power and Energy
• /
• v.6 no.4
• /
• pp.393-397
• /
• 2020

Shunt reactor, a facility for reactive power compensation, is switched several times a day depending on the load pattern. When the circuitbreaker opens the shunt reactor over-voltage is generated by several factors which degrade the insulating performance of internal parts of the circuit-breaker and cause severe voltage stress on the equipment in the power system. Transient phenomenon occurring during the switching of shunt reactor are available in laboratories that verify the performance of the circuit-breaker by simulating the power system. However, it is difficult to measure the transient phenomenon that occurs during actual operation in actual power system due to many limitations. Therefore, this paper deals with the modeling using EMTP to analyze the reignition and current chopping which causes more severe transient recovery voltage in the small inductive current breaking in actual power systems. In addition, this paper analyzes the main phenomenon that cause circuit-breaker failure in opening shunt reactor using EMTP model.

• Korea Trade Review
• /
• v.44 no.1
• /
• pp.301-319
• /
• 2019

This study is to review the Joseon government's attempt to recover the tariff autonomy lost in the course of entering into the unequal treaty with then-Japan government, as well as the practical effort to realize such an attempt. Among other attempts, the Joseon government ① began imposing tariffs starting September 1878 by establishing Dumopo Customs Office in Busan, ② dispatched on April 1881 a group of investigators to the competent authorities to review and look back the Joseon's tariff system against Japan and ③ entered into a tariff negotiation with then-Japan government on September 1881 with the emissary (Susinsa) Byeong-ho Jo representing the Joseon government. A series of these attempts, in line with each other, represents the Joseon government's ceaseless, constant effort to recover the tariff autonomy, which is what this study intends to review from the modern-day perspectives. Authored by Byeong-ho Jo to capture an advantageous position in the 1881's tariff negotiation against then-Japan government, 「Joilseui」 successfully represented the Joseon government's position on matters of ① the Japanese tax-autonomous district in Korea, ② defining tariff rates, ③ use of Japanese Yen for payment of tariffs, ④ effective period of the treaty and ⑤ export restrictions on grains. Failure of the Joseon government's attempt to recover the Tariff autonomy was attributable not only to, as 「Joilseui」 defined, ① governments' non-cooperative attitudes on the negotiation table, ② lack of authorities that the entrusted bodies had, ③ import tariffs defined high and ④ export restrictions on grains and red ginseng, but also to loss of the tariff autonomy in 1876 and the 1881's negotiation broken down that were plotted by then-Japan government's invasive policy.

• Journal of Internet Computing and Services
• /
• v.23 no.2
• /
• pp.19-28
• /
• 2022

In this paper, we propose an guidance system about closure using push notification of smart device. Restaurant operators can use the proposed application to schedule and modify the restaurant closures for a week from push notification and users can check the restaurant information and whether it is closed or not through the proposed application. The proposed method uses a server system to provide closed information, and the proposed application performs push notifications to the restaurant operator every morning to confirm the day's closed again. To verify the utility of the proposed system, we built a closure management application, user application, and server system to conduct experiments for restaurant closures guidance, resulting in 96% about checking opening hours. And we confirmed that the proposed method is better than the existing information service in comparison experiments. Thus, the proposed method will be a useful service system that could easily share closure information with restaurant operators and users.

• Journal of Energy Engineering
• /
• v.17 no.3
• /
• pp.139-144
• /
• 2008

Recently due to march as the high oil price, It is necessary for Korea to grope a plan, which is to increase the energy efficiency of existing facilities as well as to develop overseas gas and oil resources. With this point, this work carried out to approach the high pressure LNG pipeline network of Inchon receiving terminal with Newton method as corrective flowrate. We found that the high pressure network mainly depends on FCVs(Flow Control Valves). The high pressure pump showed the maximum efficiency at the FCVs of 50% opening and could discharge LNG only above the LNG head of 1,500m from a system curve obtained. The operating cost of pumps was estimated from their operating points. We compared the operating cost under normal operation with the operating cost under maximum efficiency. Especially, we obtained the day savings of a year as wells as the hour savings of a day. From the results, the high pressure network win be able to reduce the operating cost of 138 million wons in a year. This means that a pump can reduce the operating cost of 9,823 thousands won. Consequently, this work could find the operating features of the pumps under the complicated high pressure LNG network and the savings effect of the pump operating cost. Also, the results will be able to macroscopically contribute the heightening of national energy competitiveness as well as to microscopically contribute the future effective operation of LNG receiving terminal.

• Archives of design research
• /
• v.13
• /
• pp.153-162
• /
• 1996

The residence space has been in the trend of being expanded with the J'l'cent economic growth Therefore PAC may be said to have [wen from business use to home US(: the progressed living standard as the goods ior Uw "ummel' S('dSOn rest'ntly though sold in Uw fast for mainly buslTw"s use. PAC has been in the demand day ;lner day and in the tn'nd on the bc,ing the necessJty of the n'sent wf',lther warming phenomenon This study is the case study nf the products development and design process of PAC which has bpcn llrivcn and developed by Gold Star Co. ,Ltd. Which .is the firm for home electric appliances representing Korea. This studies for the development and the design of the products by the firm thus emphasizing the visulizing it based on this study. For example as they being the goods for the summer season I have tried to know the physical quakity and the characters of koreans by the weather conditions and estimated the demand by setting up the target customers of the PAC as the customers' environment. And I analyzed the acts in the living room in the apartments as the living envinorment which has the direct relation with PAC and also became a help to the moulding work of PAC by analyzing the complete interior image in the living room. In the practical moulding work the Design concept was classified into the envinorment of customer, living and products to drive as the below. Firstly - New shape (Round slim) has been realized which leads the minimizing the moulding space and visul sense of opening as its being spacious. The 2nd - the high class sense of the products which are harmonious with the atmosphere of the living room by making it interiorized has been visible. The 3rd - The shape stimulating the sensitivity of the users and surface treatment are emphasized by making it be touched. The 4th - During inviting use of technology image which appears in the electronics products are attemptedby making it be high quality.king it be high quality.