• Title/Summary/Keyword: Power Estimation

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Estimation of Overall Heat Transfer Coefficient for Single Layer Covering in Greenhouse (일중 피복온실의 관류열전달계수 산정)

  • Hwang, Young-Yun;Lee, Jong-Won;Lee, Hyun-Woo
    • Journal of Bio-Environment Control
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    • v.22 no.2
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    • pp.108-115
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    • 2013
  • This study was conducted to suggest a model to calculate the overall heat transfer coefficient of single layer covering for various greenhouse conditions. There was a strong correlation between cover surface temperature and inside air temperature of greenhouse. The equations to calculate the convective and radiative heat transfer coefficients proposed by Kittas were best fitted for calculation of the overall heat transfer coefficient. Because the coefficient of linear regression between the calculated and measured cover surface temperature was founded to 0.98, the slope of the straight line is 1.009 and the intercept is 0.001, the calculation model of overall heat transfer coefficient proposed by this study is acceptable. The convective heat transfer between the inner cover surface and the inside air was greater than the radiative heat transfer, and the difference increased as the wind speed rose. The convective heat transfer between the outer cover surface and the outside air was less than the radiative heat transfer for the low wind speed, but greater than for the high wind speed. The outer cover convective heat flux increased proportion to the inner cover convective heat flux linearly. The overall heat transfer coefficient increased but the cover surface temperature decreased as the wind speed increased, and the regression function was founded to be logarithmic and power function, respectively.

Framework for Optimum Scale Determination for Small Hydropower Development Using Economic Analysis (경제성분석에 의한 소수력 개발의 최적규모 결정 방안)

  • Kim, Kil-Ho;Yi, Choong-Sung;Lee, Jin-Hee;Shim, Myung-Pil
    • Journal of Korea Water Resources Association
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    • v.40 no.12
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    • pp.995-1005
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    • 2007
  • This study presents a framework for optimum scale determination for small hydropower development in a river basin. The framework includes the construction of hydrology and topography data, the simulation of hydropower operation, the economic analysis, and the determination of optimum scale of the small hydropower. The optimum scale of design flow and facility are determined by Net Present Value among economic analysis indices. The investment cost is estimated by the cost function derived from the construction cost of existing small hydropower plants. The benefit from power generation is estimated by the price announced by government. The presented framework is applied to the two potential sites in Cho River basin for the dam and run-of-river type of plants. Finally, the sensitivity analysis for a design flow and scale of the plant is performed for the each site. The usage of the framework presented in the study is highly expected for the estimation of potential hydropower resources or the decision support tool for a proprietor by estimating the optimum scale and economical feasibility in advance.

A Model-based Methodology for Application Specific Energy Efficient Data path Design Using FPGAs (FPGA에서 에너지 효율이 높은 데이터 경로 구성을 위한 계층적 설계 방법)

  • Jang Ju-Wook;Lee Mi-Sook;Mohanty Sumit;Choi Seonil;Prasanna Viktor K.
    • The KIPS Transactions:PartA
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    • v.12A no.5 s.95
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    • pp.451-460
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    • 2005
  • We present a methodology to design energy-efficient data paths using FPGAs. Our methodology integrates domain specific modeling, coarse-grained performance evaluation, design space exploration, and low-level simulation to understand the tradeoffs between energy, latency, and area. The domain specific modeling technique defines a high-level model by identifying various components and parameters specific to a domain that affect the system-wide energy dissipation. A domain is a family of architectures and corresponding algorithms for a given application kernel. The high-level model also consists of functions for estimating energy, latency, and area that facilitate tradeoff analysis. Design space exploration(DSE) analyzes the design space defined by the domain and selects a set of designs. Low-level simulations are used for accurate performance estimation for the designs selected by the DSE and also for final design selection We illustrate our methodology using a family of architectures and algorithms for matrix multiplication. The designs identified by our methodology demonstrate tradeoffs among energy, latency, and area. We compare our designs with a vendor specified matrix multiplication kernel to demonstrate the effectiveness of our methodology. To illustrate the effectiveness of our methodology, we used average power density(E/AT), energy/(area x latency), as themetric for comparison. For various problem sizes, designs obtained using our methodology are on average $25\%$ superior with respect to the E/AT performance metric, compared with the state-of-the-art designs by Xilinx. We also discuss the implementation of our methodology using the MILAN framework.

An Indirect Localization Scheme for Low- Density Sensor Nodes in Wireless Sensor Networks (무선 센서 네트워크에서 저밀도 센서 노드에 대한 간접 위치 추정 알고리즘)

  • Jung, Young-Seok;Wu, Mary;Kim, Chong-Gun
    • Journal of the Institute of Convergence Signal Processing
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    • v.13 no.1
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    • pp.32-38
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    • 2012
  • Each sensor node can know its location in several ways, if the node process the information based on its geographical position in sensor networks. In the localization scheme using GPS, there could be nodes that don't know their locations because the scheme requires line of sight to radio wave. Moreover, this scheme is high costly and consumes a lot of power. The localization scheme without GPS uses a sophisticated mathematical algorithm estimating location of sensor nodes that may be inaccurate. AHLoS(Ad Hoc Localization System) is a hybrid scheme using both GPS and location estimation algorithm. In AHLoS, the GPS node, which can receive its location from GPS, broadcasts its location to adjacent normal nodes which are not GPS devices. Normal nodes can estimate their location by using iterative triangulation algorithms if they receive at least three beacons which contain the position informations of neighbor nodes. But, there are some cases that a normal node receives less than two beacons by geographical conditions, network density, movements of nodes in sensor networks. We propose an indirect localization scheme for low-density sensor nodes which are difficult to receive directly at least three beacons from GPS nodes in wireless network.

Technology Trends and Future Prospects of Satellite-Based Photovoltaic Electricity Potential (위성기반 태양광 발전가능량 산출기술 개발 동향 및 향후 전망)

  • Han, Kyung-Soo;Kim, Jinsoo
    • Korean Journal of Remote Sensing
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    • v.32 no.6
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    • pp.579-587
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    • 2016
  • To obtain a stable energy supply and manage PhotoVoltaic (PV) systems efficiently, satellite imagery methods are being developed to estimate the solar PV potential. This study analyzed trends in the use of satellite imagery in solar PV and solar irradiation estimation technology. The imaging technology is used to produce solar energy resource maps. The trend analysis showed that the level of solar PV technology in Korea is 30% below that of advanced countries. It is impossible to raise such low-level technologies to the levels of advanced countries quickly. Intensive research and development is the only way to achieve the 80% technology level of advanced countries. The information produced in this process can contribute to the management of solar power plants. A valid technology development strategy would be to obtain effective data that can be used for fieldwork. Such data can be produced by estimating solar irradiation very accurately with several-hundred-meter resolution using Communication, Ocean, and Meteorological Satellites (COMS) and next-generation GEO-KOMPSAT 2A, developing core technologies for short- and medium-term irradiation prediction, and developing technologies for estimating the solar PV potential.

Sensitivity Analysis of Nozzle Geometry Variables for Estimating Residual Stress in RPV CRDM Penetration Nozzle (원자로 상부헤드 관통노즐의 잔류응력 예측을 위한 노즐 형상 변수 민감도 연구)

  • Bae, Hong Yeol;Oh, Chang Young;Kim, Yun Jae;Kim, Kwon Hee;Chae, Soo Won;Kim, Ju Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.3
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    • pp.387-395
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    • 2013
  • Recently, several circumferential cracks were found in the control rod drive mechanism (CRDM) nozzles of U.S. nuclear power plants. According to the accident analyses, coolant leaks were caused by primary water stress corrosion cracking (PWSCC). The tensile residual stresses caused by welding, corrosion sensitive materials, and boric acid solution cause PWSCC. Therefore, an exact estimation of the residual stress is important for reliable operation. In this study, finite element simulations were conducted to investigate the effects of the tube geometry (thickness and radius) on the residual stresses in a J-groove weld for different CRDM tube locations. Two different tube locations were considered (center-hole and steepest side hill tube), and the tube radius and thickness variables ($r_o/t$=2, 3, 4) included two different reference values ($r_o$=51.6, t=16.9mm).

Estimation of Economic Value of the Film Industry in the National Economy (영화산업의 경제적 파급효과 분석)

  • Bae, Ki-Hyung
    • The Journal of the Korea Contents Association
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    • v.12 no.9
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    • pp.172-181
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    • 2012
  • The film industry is a high value-added industry, boosts the self-esteem of the people as a measure of a country's culture industry, and is one of the strategic industries to be fostered. However, the film industry is struggling due to the lack of national consensus on the importance and value of the film industry. Therefore, in order to resolve this issue, the study used the film Input-Output Table of year 2009 of korea to analyze how much the film industry contributes to the national economy. The results shows that film industry induce 82,838.7 billion won of national production, especially the film industry(the sector of film product & distribution and film screenings) shows that production inducement coefficient is 2.324(2.240, 2.478), Index of the power of dispersion is 1.163(1.121, 1.240), index of the sensitivity of dispersion is 0.825(0.825, 0.501), value-added coefficient is 0.884(0.479, 0.547), income inducement coefficient is 0.454(0.211, 0.236), tax inducement coefficient is 0.110(0.090, 0.146) and employment inducement coefficient is 0.017(0.014, 0.022).

Analysis on the Characteristics of Rock Blasting-induced Vibration Based on the Analysis of Test Blasting Measurement Data (시험발파 계측자료 분석을 통한 암석 발파진동 특성 분석)

  • Son, Moorak;Ryu, Jaeha;Ahn, Sungsoo;Hwang, Youngcheol;Park, Duhee;Moon, Duhyeong
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.9
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    • pp.23-32
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    • 2015
  • This study examined blast testing measurement data which had been obtained from 97 field sites in Korea to investigate the comprehensive characteristics of rock blasting-induced vibration focusing on the effect of excavation types (tunnel, bench) and rock types. The measurement data was from the testing sites mostly in Kangwon province and Kyungsang province and rock types were granite, gneiss, limestone, sand stone, and shale in the order of number of data. The study indicated that the blasting-induced vibration velocity was affected by the excavation types (tunnel, bench) and bench blasting induced higher velocity than tunnel blasting. In addition, the vibration velocity was also highly affected by the rock types and therefore, it can be concluded that rock types should be considered in the future to estimate a blasting-induced vibration velocity. Furthermore, the pre-existing criteria was compared with the results of this study and the comparison indicated that there was a discernable difference except for tunnel blasting results based on the square root scaling and therefore, further studies and interests, which include the effects of rock strength, joint characteristics, geological formation, excavation type, power type, measurement equipment and method, might be necessarily in relation to the estimation of blasting-induced vibration velocity in rock mass.

Field Tracer Experiments under Severe Wether Conditions for the Validation of the Dispersion of Radioactive Materials (방사능 확산 검증을 위한 악기상 조건에서의 추적자 야외확산 실증실험)

  • Han, Moon Hee;Kim, Eun Han;Jeong, Hyo Joon;Jeong, Hae Sun;Park, Mi Sun;Hwang, Won Tae
    • Journal of Radiation Protection and Research
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    • v.38 no.4
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    • pp.208-213
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    • 2013
  • The suitability of the site criteria is a basic requirement for securing safety of nuclear power plants. The suitability should be confirmed through the estimation of environmental radiation effects at the exclusion area boundary under the severe weather conditions. In this study, field tracer experiments over short range of 1 km radius under severe weather conditions were conducted at flat area in Daejeon. Severe weather conditions are represented with stable atmospheric condition and low wind speed. In general, the condition is appeared at clean night time with weak wind. The analysis of the measured distribution of the released tracer gas shows two big differences between the results of the past experiments conducted under the favorable weather conditions. One is the difficulty of finding the typical distribution of the released tracer gas with peak concentration in the downwind direction. The other one is the appearance of the contour of the concentration of tracer gas at several hundred meters even though the gas released at 10 m height over the ground.

Estimation of In-plant Source Term Release Behaviors from Fukushima Daiichi Reactor Cores by Forward Method and Comparison with Reverse Method

  • Kim, Tae-Woon;Rhee, Bo-Wook;Song, Jin-Ho;Kim, Sung-Il;Ha, Kwang-Soon
    • Journal of Radiation Protection and Research
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    • v.42 no.2
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    • pp.114-129
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    • 2017
  • Background: The purpose of this paper is to confirm the event timings and the magnitude of fission product aerosol release from the Fukushima accident. Over a few hundreds of technical papers have been published on the environmental impact of Fukushima Daiichi accident since the accident occurred on March 11, 2011. However, most of the research used reverse or inverse method based on the monitoring of activities in the remote places and only few papers attempted to estimate the release of fission products from individual reactor core or from individual spent fuel pool. Severe accident analysis code can be used to estimate the radioactive release from which reactor core and from which radionuclide the peaks in monitoring points can be generated. Materials and Methods: The basic material used for this study are the initial core inventory obtained from the report JAEA-Data/Code 2012-018 and the given accident scenarios provided by Japanese Government or Tokyo Electric Power Company (TEPCO) in official reports. In this research a forward method using severe accident progression code is used as it might be useful for justifying the results of reverse or inverse method or vice versa. Results and Discussion: The release timing and amounts to the environment are estimated for volatile radioactive fission products such as noble gases, cesium, iodine, and tellurium up to 184 hours (about 7.7 days) after earthquake occurs. The in-plant fission product behaviors and release characteristics to environment are estimated using the severe accident progression analysis code, MELCOR, for Fukushima Daiichi accident. These results are compared with other research results which are summarized in UNSCEAR 2013 Report and other technical papers. Also it may provide the physically based arguments for justifying or suspecting the rationale for the scenarios provided in open literature. Conclusion: The estimated results by MELCOR code simulation of this study indicate that the release amount of volatile fission products to environment from Units 1, 2, and 3 cores is well within the range estimated by the reverse or inverse method, which are summarized in UNSCEAR 2013 report. But this does not necessarily mean that these two approaches are consistent.