• Title/Summary/Keyword: Current spreading

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A Prediction Method of Tension on Containment Boom for Marine Floating Debris (부유물 차단막에 작용하는 장력추정에 관한 실험연구)

  • Yu J. S.;Sung H. G.;Ryu J. M.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.6 no.2
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    • pp.63-71
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    • 2003
  • The main functions of containment boom for marine floating debris are to prevent spreading of the marine floating debris and to effectively collect the trash skimmer. The design characteristics of containment boom for marine floating debris in wave, current and wind are investigated. The response of a containment boom on the current is a function of a number of parameters, such as geometric characteristics, buoyance/weight ratio and towing velocity. To understand the relationship between these design parameters more clearly, a series of tests with three models with the variation of current speed and gap ratio was conducted. The model tests results are developed to new numerical equation that is tension prediction method of containment boom for marine floating debris. Also its is compared with open sea experimental results.

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A Three-Dimensional Modeling Study of Lake Paldang for Spatial and Temporal Distributions of Temperature, Current, Residence Time, and Spreading Pattern of Incoming Flows (팔당호 수온, 유속, 체류시간의 시.공간적 분포 및 유입지류 흐름에 관한 3차원 모델 연구)

  • Na, Eun-Hye;Park, Seok-Soon
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.9
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    • pp.978-988
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    • 2005
  • A three-dimensional dynamic model was applied to Lake Paldang, Han River in this study. The model was calibrated and verified using the data measured under different ambient conditions. The model results were in reasonable agreements with the field measurements in both calibration and verification. Utilizing the validated model, we analyzed the spatial and temporal distributions of temperature, current, residence time, and spreading pattern of incoming flows within the lake. Relatively low velocity and high temperature were computed at the surface layer in the southern region of the Sonae island. The longest residence time within the lake was predicted in the southern region of the Sonae island and the downstream region of the South Branch. This can be attributed to the fact that the back currents caused by the dam blocking occur mainly in these regions. Vertical thermal profiles indicated that the thermal stratifications would be occurred feebly in early summer and winter. During early spring and fall, it appeared that there would be no discernible differences at the vertical temperature profiles in the entire lake. The vertical overturns, however, do not occur during these periods due to an influence of high discharge flows from the dam. During midsummer monsoon season with high precipitation, the thermal stratification was disrupted by high incoming flow rates and discharges from the dam and very short residence time was resulted in the entire lake. In this circulation patterns, the plume of the Kyoungan stream with smallest flow rate and higher water temperature tends to travel downstream horizontally along the eastern shore of the south island and vertically at the top surface layer. The model results suggest that the Paldang lake should be a highly hydrodynamic water body with large spatial and temporal variations.

Experts View and Recommendation for Management and Operation of National Health Promotion Fund (국민건강증진기금 운영과 개선방향에 대한 전문가의 인식)

  • Kim, Hye-Ryun;Yeo, Jiyoung
    • Korean Journal of Health Education and Promotion
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    • v.31 no.3
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    • pp.83-95
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    • 2014
  • Objectives: This study was to examine the experts perception on the operation of the national health promotion fund and related policies, and to obtain the perspective on the improving governance of the fund. Methods: Experts opinion survey was recruited 120 experts who were public health officials, and members of board in academic societies related to health promotion and health policy, and 60 experts participated in the survey. Results: Most health care experts agreed that the current allocation of health promotion fund was not optimal with its lack of allocation on promoting healthy lifestyle and R&D for health promotion, while the majority of the fund was being spent on supporting national health insurance. Thus, establishing governance system and control tower for the fund was viewed as critical. Also the status of deliberation committee should be raised to higher position where it can hold practical authority to plan and evaluate fund spending. Conclusions: The priority of health promotion fund spending should be more on improving health such as modifying life-style and spreading healthy habits, rather than on disease management or subsidizing health insurance. It is recommended that change from to environment in health promotion policy regime is required to establish effective governance system for the fund operation.

Numerical Simulation on Longshore Current Produced by Random Sea Waves (불규칙파에 의한 연안류의 수치계산)

  • 권정곤
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.3 no.1
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    • pp.54-64
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    • 1991
  • To accurately estimate the rate of sediment transport in shallow water bodies, it is necessary to investigate the irregular waves transformation characteristics and nearshore currents produced by random sea waves. Most of studies on numerical models for nearshore currents are based on the theory of monocromatic waves and thus, very few nearshore models take into account the effect of irregularities in the hight, period and directional spreading of incident waves. The numerical simulation model for nearshore currents used in this paper considers the effect of irregularities of incident waves, based on Individual Wave Analysis. The computational results are compared and shown in a reasionable agreement with the experimental data.

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Profitability Analysis of ESS with PV Generation (PV연계형 ESS의 설치 규모에 따른 수익영향)

  • Kim, Chang Soo;Choi, Sang Bong
    • Current Photovoltaic Research
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    • v.8 no.3
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    • pp.86-93
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    • 2020
  • The investment in solar and wind generation is rapidly increasing with government's renewable expansion policy and Renewable Portfolio Standard (RPS). Since the large penetration of solar and wind generation increases the variability and uncertainty of supply and demand balance in power system, the government is pursuing the policy of supplying energy storage system (ESS) linked to renewable energy. ESS contributes to the ease of transmission and distribution grid by shifting PV generation from daytime to evening hours. Recently, the declining market price of REC as ESS incentive, policies to cut down incentives and limited ESS storage due to fire events lead to the aggravation of long-term profitability, thus working as a barrier of ESS spreading. In this study, the factors affecting the profit of ESS are analyzed and brief indicators are derived. Based on the indicators, the profit changes are analyzed considering the variation of REC market price and REC incentive weights. Based on the profit change with respect to the increase of ESS capacity, economical ESS installation capacity is suggested.

Development of 100kW Grid-Connected PCS for Vanadium Redox flow Battery (바나듐 레독스 플로우 전지용 100kW급 계통연계형 PCS 개발)

  • Choi, Eun-Sik;Lee, Chung-Woo;Ryu, Kang-Yeul;Kang, Byung-Kwan;Oh, Seung-Hun;Lee, Yun-Jae;Koh, Kwang-Soo;Kim, Hee-Jung
    • Proceedings of the KIPE Conference
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    • 2013.11a
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    • pp.115-116
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    • 2013
  • Recently environmental problems such as greenhouse gas emissions has become a global problem. As a result, the current that can be easily used to Petroleum and coal reserves of fossil energy and environmental issues, coupled with the limitations of this finding for renewable energy to replace the movement is spreading around the world. Among them Energy Storage System with secondary battery technology has been increased interest in, Redox flow batteries, unlike the conventional theory, the life of the rechargeable battery almost no restrictions existing lithium-ion batteries 10 times more than the life of the road. In this paper, power plant or power system, installed in a building that can cope with the rapid increase in demand for power redox flow battery for 100kW PCS will be introduced.

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The Public Service Charter in the Republic of Korea : A Development plan for Government innovation (행정서비스헌장제도의 발전과 정부혁신)

  • Kim, Guk-Hyeon
    • Journal of Digital Convergence
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    • v.4 no.1
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    • pp.55-71
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    • 2006
  • The Public Service Charter is one of the administrative reform programs introduced to promote customer oriented administration. It's main purpose is to achieve citizens' confidence in the government by satisfying them with elevated quality of the public services. This study focuses on analyzing current conditions and achievements of the Public Service Charter in the Republic of Korea and proposing it's development plan. Since it was introduced to Korea in 1998, the Public Service Charter has been disseminated and contributed to the spreading of the citizens' understandings of the government's initiatives for customer satisfaction plans. Still, it has several problems as follows; A lot of public servants and citizens lack in understandings of this program. CEOs don't have enough concern in it. Evaluation is not organically connected to performance management. The correction and compensation procedure are not well operated. To solve these problems, the government needs to set up an institutional foundation establishing a legal base, uplifting CFO' concerns, and building a department with full responsibility, and to promote employees and citizens' participation through education and PR. It's also important to enhance post management by efficient evaluation and performance management, substantial correction and compensation procedure.

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A Study of a Scheme on the Export Promotion of the Digital Content Industry with the Spread of Hallyu Culture (한류문화 확산에 따른 디지털콘텐츠 산업의 수출확대방안 연구)

  • Lee, Chung-Bael;Lee, Jung-Min
    • International Commerce and Information Review
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    • v.8 no.2
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    • pp.79-98
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    • 2006
  • With shifting the paradigm to digital economy, the digital industry becomes one of the national strategic industries. The digital industry has not only significant effects on forward and backward related industries but is also creating its own value. Furthermore, the effects of conversion with diverse products also play an important role in adding value. Since the early 2000s, Korea's culture so called 'Hallyu' (Korean wave) has been spreading to neighboring Asian countries such as China, Japan, Hong Kong, Therefore we have a good opportunity to increase our competitiveness with the development of the digital content industry using various base resources in conjunction with the spread of Hallyu culture in the Southeast Asian region. In this paper we attempt to suggest several schemes to promote our exports of digital contents while analyzing the current status of the Korean digital industry and addressing some problems and barriers to the export of the digital content industry. There are several schemes to be proposed in order to promote Korean exports of digital contents, as follows: 1) to foster global digital contents, 2) to establish a supporting system, 3) to build a marketing and R&D center, 4) to operate a test-bed of digital contents and 5) to fund expenses such as marketing.

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Progressive Process Design of Integrated Part for Mobile Phone (모바일 폰용 일체형 부품의 프로그레시브 성형공정 설계)

  • Chang, M.J.;Kim, G.H.;Lee, C.J.;Kim, B.M.;Lee, S.B.;Ko, D.C.
    • Transactions of Materials Processing
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    • v.20 no.2
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    • pp.110-117
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    • 2011
  • The purpose of this work is to develop of a press forming process for mobile phone battery cover as an alternative to the current manufacturing process by laser welding. This press forming process consists of a combination of bending, side pressing and side bending operations. The dimensional error for each process was investigated by finite element(FE) analysis and the Taguchi optimization method. The spreading of the cover width in the side pressing process was adjusted by modifying the blank shape with a notch. The over-bending method was adopted to compensate the spring-back which occurs after bending. Forming experiments were performed to verify the reliability of the developed press forming process. In addition, the strength of the product was evaluated to verify the suitability of the battery cover manufactured with this new press forming process. The results of the forming experiments indicate that the dimensional accuracy of the battery cover is within the required tolerance. The strength of the battery cover was evaluated to 547N which is larger than required strength of 400N.

Insulator application and prospect (가공송전선로 애자 적용실태와 향후 전망)

  • Kim, Woo-Kyum;Min, Byeong-Wook;Kim, Tai-Young;Wi, Hwa-Bog;Choi, Jin-Sung;Lee, Buk-Chang
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.327_328
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    • 2009
  • The insulator being used for transmission line is to mount the charged conductor on the tower or other supports. The insulators are classified according to its material: porcelain, glass and polymer. Polymer insulators are also called as composite insulator or non ceramic insulator (NCI). Insulators are a major element of a power transmission system. Since a faulty insulator can lead to a wide spreading blackout, it must have sufficient mechanical and electrical strength. It must be durable, have high electrical insulation and be able to withstand a leakage current. It must also be able to withstand the toughest weather conditions. In Korea, porcelain insulators have been used widely. However, to make compact equipment and keep up with global trends, we have enhanced domestic production of polymer insulator and are encouraging its applications. Accordingly, this thesis will look at types of insulators, use and trends, and prospects of insulators application in the field.

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