• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.155.2-155
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• 2002

A visual environment for system analysis codes (hereinafter called "ViSA") has been developed to support code users in their input preparations, code executions, and output interpretations. ViSA provides a more convenient way for base input data generation and modification on a user-friendly basis. It also provides on-line graphical displays to give an in-depth understanding of transient thermal-hydraulic behaviors in nuclear power plants. This paper presents the main features of ViSA.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2455-2458
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• 2003

In this paper, the Classification of Energy Labeling has been Proposed. Energy Parameters of input signal which is extracted from each phoneme is labelled. And groups of labelling according to detected energies of input signals are detected. Next, DTW processes in a selected group of labeling. This leads to DTW processing faster than a previous algorithm. In this Method, because an accurate detection of parameters is necessary on the assumption in steps of a detection of speeching duration and a detection of energy parameters, variable windows which are decided by pitch period is used. Extract algorithms don't search for exact frame energy, because 256 frame window-sizes is fixed. For this reason, a new energy extraction method has been proposed. A pitch period is detected firstly; next window scale is decided between 200 frames and 300 frames. The proposed method make it possible to cancel an influence of windows.

• Journal of Communications and Networks
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• v.18 no.4
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• pp.649-657
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• 2016

In this paper, we investigate energy efficiency (EE) of the traditional co-located and the distributed massive multiple-input multiple-output (MIMO) systems. First, we derive an approximate EE expression for both the idealistic and the realistic power consumption models. Then an optimal energy-efficient remote access unit (RAU) selection algorithm based on the distance between the mobile stations (MSs) and the RAUs are developed to maximize the EE for the downlink distributed massive MIMO systems under the realistic power consumption model. Numerical results show that the EE of the distributed massive MIMO systems is larger than the co-located massive MIMO systems under both the idealistic and realistic power consumption models, and the optimal EE can be obtained by the developed energy-efficient RAU selection algorithm.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.117-129
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• 2002

Concentration of welding fumes and their components is known to be hazardous to welder and adjacent worker. To determine the generation rates of metals in fumes, $CO_2$ flux cored arc welding on stainless steel was performed in well designed fume collection chamber. Variables were different products of flux cored wire(2 domestic products and 4 foreign products) and input energy(low-, optimal- , high input energy). Mass of welding fumes was determined by gravimetric method(NIOSH 0500 method), and 17 metals were analysed by inductively coupled plasm-atomic emission spectroscopy(NIOSH 7300 method). Flux cored wire tube and flux were analysed by scanning electron microscopy to determine their metal composition. 17 metals were classified by their generation rates. Generation rates of iron, manganese, potassium and sodium were all above 50mg/min at optimal input energy level. Generation rates of chromium and amorphous silica were 25~50mg/min. At 1~25mg/min level, nickel, titanium, molybdenum, and aluminum were included. Copper, zinc, calcium, lead, magnesium, lithium, and cobalt were generated below 1 mg/min. Generation rates of metal components in fumes were influenced by input energy, types of flux cored wire. Flux cored wire was consisted of outer shell tube and inner flux. Iron, chromium, and nickel were the major components of outer tube. Flux contained iron, chromium, nickel, potassium, sodium, silica, and manganese. The use of flux cored wire can increase the hazards by increasing the amounts of fumes formed relative to that of solid wire. The reason might be the direct transfer of elements from the flux, since the flux is fine power. Ratio of metals to the fume of flux cored wire was lower than that of solid wire because non-metal components of flux were transferred. Total metal content of fumes in flux cored arc welding was 47.4(24.3~57.2) percent that is much lower than that of solid wire, 75.9 percent. We found that generation rates of iron, manganese, chromium and nickel, all well known to cause work related disease to welder, increased more rapidly with increasing input energy than those of fumes. To reduce worker exposure to fumes and hazardous component at source, further research is needed to develop new welding filler materials that decrease both the amount of fumes and hazardous components.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.3
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• pp.1-8
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• 2017

Variable refrigerant flow (VRF) systems have recently attracted attention in many countries due to a variety of advantages over conventional system. Especially, the water-cooled VRF heat pump, including geothermal heat pump, is a system that accurately controls the flow rate of refrigerant for the improved efficiency under part load operation. This paper describe the process of generating the cooling and heating energy performance curve coefficients and performance expressions for modeling water cooled VRF system using EnergyPlus. Through this study, the process for generating performance curves can be implemented into EnergyPlus or other comparable building energy analysis tools for the long-term evaluation of heat pump under dynamic conditions.

• Korean Journal of Computational Design and Engineering
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• v.20 no.1
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• pp.11-21
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• 2015

Currently, the United States, the United Kingdom, Australia etc. are actively utilizing energy simulation for efficiency evaluation of building energy. However, domestic energy efficiency assessment system doesn't use energy simulation system properly at present: parameters based architecture plans and Ashrae Standard are inputted for the evaluation, because the input parameters for the simulation haven't been established yet. This fact causes poor reliability during energy simulation, as the values of the two standards are different from each other. Therefore, the aim of the study is to set domestic standard parameter for BIM-based energy performance evaluation, focusing on possession area per person of occupants at government office in Korea. We found that the difference among the result values occurred approximately 3% in the energy simulation. As a result of the analysis, possession area per person of occupants in Government office is $31.87m^2$. Other input parameters may be set based on this. This will increase the reliability of energy simulation through a domestic standard parameter.

• Journal of Power Electronics
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• v.12 no.6
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• pp.912-924
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• 2012

In hybrid renewable power systems, the use of a multiple-input dc/dc converter (MIC) leads to simpler circuit and lower cost, when compared to the conventional use of several single-input converters. This paper proposed a novel three-input buck/boost/buck-boost converter, which can be used in applications with various values of input voltage. The energy sources in this converter can deliver power to the load either simultaneously or individually in one switching period. The steady relationship, the power management strategy and the small-signal circuit model of this converter have been derived. With decoupling technology, modeling and regulator design can be obtained under multi-loop control modes. Finally, three generating methods of a multiple-input buck/boost/buck-boost converter is given, and this method can be extended to the other multiple-input dc/dc converters.

• Earthquakes and Structures
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• v.8 no.5
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• pp.957-976
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• 2015

Recently, two energy-based response parameters, i.e., the absolute and the relative elastic input energy equivalent velocity, have been receiving a lot of research attention. Several studies, in fact, have demonstrated the potential of these intensity measures in the prediction of the seismic structural response. Although some ground motion prediction equations have been developed for these parameters, they only provide marginal distributions without information about the joint occurrence of the spectral values at different periods. In order to build new prediction models for the two equivalent velocities, a large set of ground motion records is used to calculate the correlation coefficients between the response spectral values corresponding to different periods and components of the ground motion. Then, functional forms adopted in models from the literature are calibrated to fit the obtained data. A new functional form is proposed to improve the predictions of the considered models from the literature. The components of the ground motion considered in this study are the two horizontal ones only. Potential uses of the proposed equations in addition to the prediction of the correlation coefficients of the equivalent velocity spectral values are shown, such as the prediction of derived intensity measures and the development of conditional mean spectra.

• Environmental Engineering Research
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• v.17 no.2
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• pp.89-94
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• 2012

Pyrolysis/gasification technology utilizes an energy conversion technique from various waste resources, such as biomass, solid waste, sewage sludge, and etc. to generating a syngas (synthesis gas). However, one of the major problems for the pyrolysis gasification is the presence of tar in the product gas. The tar produced might cause damages and operating problems on the facility. In this study, a gliding arc plasma reformer was developed to solve the previously acknowledged issues. An experiment was conducted using surrogate benzene and naphthalene, which are generated during the pyrolysis and/or gasification, as the representative tar substance. To identify the characteristics of the influential parameters of tar decomposition, tests were performed on the steam feed amount (steam/carbon ratio), input discharge power (specific energy input, SEI), total feed gas amount and the input tar concentration. In benzene, the optimal operating conditions of the gliding arc plasma 2 in steam to carbon (S/C) ratio, 0.98 $kWh/m^3$ in SEI, 14 L/min in total gas feed rate and 3.6% in benzene concentration. In naphthalene, 2.5 in S/C ratio, 1 $kWh/m^3$ in SEI, 18.4 L/min in total gas feed rate and 1% in naphthalene concentration. The benzene decomposition efficiency was 95%, and the energy efficiency was 120 g/kWh. The naphthalene decomposition efficiency was 79%, and the energy yield was 68 g/kWh.

• New & Renewable Energy
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• v.5 no.4
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• pp.68-73
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• 2009

국가 에너지 안보 확보와 친환경적이고 지속적인 '저탄소 녹색성장'의 기반을 마련한다는 측면에서 신재생에너지 분야의 인력양성은 시급하고도 중요한 당면 과제이다. 본 연구에서는 신재생에너지인력양성이 원활하게 공급되지 않았을 경우 발생할 수 있는 인력공급지장효과를 분석하기 위하여 산업연관분석의 공급유도모형을 유도하고 2006년 신재생에너지 인력양성사업 배출인원을 기준으로 실증분석을 실시하였다. 또한 공급유도형의 감응도 계수와 영향력계수 분석을 통해 신재생에너지 관련 사업과 타 산업 간의 전후방연쇄효과를 비교분석하였다. 연구 수행 결과 신재생에너지 관련 산업의 평균 영향력계수는 1.37, 평균 감응도 계수는 0.96으로 최종 수요적 제조업의 성격을 띠고 있는 것으로 나타났다. 또한, 2006년 신재생에너지 인력양성사업에 의해 배출된 336명의 인력이 공급되지 않았을 경우 공급지장비용은 총 230억이며, 8개 신재생에너지원 중 태양열과 연료전지에 인력 공급지장비용이 타 에너지원에 비해 상대적으로 높은 것으로 분석되었다. 산업분류 기준으로는 일반목적용 기계 산업과 전기기계 장치 산업이 신재생 에너지 인력공급 장애에 따른 지장비용이 높은 것으로 분석되었다.