• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.255-258
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• 2009

Leading developed countries have studied energy self-sufficient houses such as zero or low energy buildings to reduce energy consumption for buildings since the early 1990s. Moreover, some developed countries have actually constructed self-sufficient houses and operated them for demonstration, expanding use of such houses. Korea has also established Zero Energy Solar House(ZeSH) and studied energy independence. Therefore, this study analyzed research result regarding ZeSH, self-sufficient energy house hold of Korea, found out technologies used for heating energy independence, used building interpretation program(ESP_r) to evaluate performance of each factors and analyzed energy reduction quantitatively. Results from the research are as follows: Reduction rate of actual detached house's heating load was also analyzed quantitatively depending on application of each technology. When each factor was applied step-by-step, annual reduction rate of heating load depending on increase in insulation thickness reached 6.6~22.2 %. Annual reduction rate of heating load depending on increase insulation thickness, and change in window heating performance and area ratio reached 31.5 %. Annual reduction rate of heating load through high-sealing and high-insulation depending on change in leakage rate reached 40.0~88.9 %. Annual reduction of heating load, when Mass Wall and attached sun space was applied were applied reached 28.5~39.2 %, respectively.

• Journal of Korea Trade
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• 제23권3호
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• pp.52-67
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• 2019

Purpose - This study analyzes the effect of the authorized economic operator-mutual recognition arrangement (AEO-MRA) on the performance of Korean exporters and importers. The effect of the import-export companies' characteristics, such as annual sales, the number of foreign markets, and overseas experience, on the AEO-MRA is deduced; the relationship between this effect and firm performance is analyzed. Design/methodology - An empirical research model was constructed and analyzed using structural equation modeling. The effect of AEO-MRA on logistics and operational performance was derived from the aforementioned characteristics as leading factors of the AEO-MRA. The regulatory influence of cooperation with logistics companies was analyzed in the AEO-MRA effect on logistics performance. Thus, 172 valid samples were obtained from import-export companies certified by the AEO-MRA. Findings - Among the aforementioned characteristics, only "annual sales" has a positive effect on the AEO-MRA, whose effect enhances logistics and operational performances. The AEO-MRA effect did not directly affect operational performance. Owing to the adjustment effect analysis, the AEO-MRA effect and logistics performance relationship is strengthened if the cooperative relationship with the logistics company is higher than a certain level. If this cooperation falls below a certain level, the AEO-MRA effect on logistics performance reduces. Thus, logistics cooperation is an important factor in the AEO-MRA effect and logistics performance relationship. Originality/value - Hinging on the resource-based theory and relational viewpoint, an empirical model that explains the relationship between the AEO-MRA effect and firm performance is established.

• 한국지열·수열에너지학회논문집
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• 제14권2호
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• pp.15-22
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• 2018

As heat pump application has been extending to residential, commercial, and industrial fields, the heat pump should have many operation modes. It is required to optimize refrigerant charge amount at all operation modes in order to enhance the annual performance of heat pumps. In this study, the performance analysis of the heat pump which has cooling, heating, cooling-hot water, heating-hot water, and hot water modes was executed with the variation of refrigerant charge amount. As the refrigerant charge amount changed, the maximum COPs of the heat pump at different operation modes were changed within ${\pm}10%$. Therefore, it is highly recommended to select optimum charge amount for the heat pump based on the analysis of annual load for each operation modes.

• Earthquakes and Structures
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• 제10권1호
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• pp.105-123
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• 2016

In this paper, using the probabilistic methods, the seismic demand of buckling restrained braced frames subjected to earthquake was evaluated. In this regards, 4, 6, 8, 10, 12 and 14-storybuildings with different buckling restrained brace configuration (including diagonal, split X, chevron V and Inverted V bracings) were designed. Because of the inherent uncertainties in the earthquake records, incremental dynamical analysis was used to evaluate seismic performance of the structures. Using the results of incremental dynamical analysis, the "capacity of a structure in terms of first mode spectral acceleration", "fragility curve" and "mean annual frequency of exceeding a limit state" was determined. "Mean annual frequency of exceeding a limit state" has been estimated for immediate occupancy (IO) and collapse prevention (CP) limit states using both Probabilistic Seismic Demand Analysis (PSDA) and solution "based on displacement" in the Demand and Capacity Factor Design (DCFD) form. Based on analysis results, the inverted chevron (${\Lambda}$) buckling restrained braced frame has the largest capacity among the considered buckling restrained braces. Moreover, it has the best performance among the considered buckling restrained braces. Also, from fragility curves, it was observed that the fragility probability has increased with the height.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.110.1-110.1
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• 2011

This study analyzed the performance of long term operation photovoltaic system The 50 kWp grid connected photovoltaic system which was installed at KEPRI site in 1999 has been operated more than 12 years. In order to acquire long term operation characteristics of medium size photovoltaic system, the operation test data related on power generation electricity and capacity factor of 50 kWp system, which have been collected since 1999, were analysed. From the analysing results, 57.7 MWh in annual power generation electricity of 50 kWp photovoltaic system in 1999 has been decreased 49.1 MWh in 2005 and reached 38.0 MWh in 2010. In addition to, the capacity factor of 50 kWp photovoltaic system also showed 13.2 % in 1999, 11.2% in 2005 and finally reached 8.8% in 2011. The operation test data showed a trend of decreasing of generation electricity and capacity factor during the 12 years operation time and we guessed that was caused by solar cell performance degradation and decreasing of PCS system efficiency.

• 농업과학연구
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• 제46권4호
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• pp.999-1006
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• 2019

Recently, the quantitative management of agricultural water supply, which is the main source for water consumption in Korea, has become more important due to the effective water management organization of the Korean government. In this study, the estimation method for irrigation supply based on agricultural reservoir storage data was improved compared to previous research, in which drought year selection was unclear, and the outlier data for the rainfall-irrigation supply were not eliminated in the regression analysis. In this study, the drought year was selected by the ratio of annual precipitation to mean annual precipitation and the storage rate observed before the start of irrigation. The outlier data for the rainfall-irrigation supply were eliminated by the Grubbs & Beck test. The proposed method was applied to nine agricultural reservoirs for validation. As a result, the ratio of annual precipitation to mean annual precipitation is less than 53% and the storage rate observed before the start of irrigation is less than 55% it was judged to be the drought year. In addition, the drought supply factor, K, was found to be 0.70 on average, showing closer results to the observed reservoir rates. This shows that water management at the real is appling drought year practice. It was shown that the performance of the proposed method was satisfactory with NSE (Nash-Sutcliffe model efficiency coefficient) and R² (coefficient of determiniation) except for a few cases.

• Korean Journal of Hydrosciences
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• 제3권
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• pp.81-96
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• 1992

This study represents the methodology for feasibility analysis of small hydro power SHP plant. Cumulative density function of Weibull distribution and Thiessen method were adopted to decide flow duration curve at SHP candidate site. The perfomance prediction model and construction cost estimation model for tunnel-type SHP plant were developed. Eight tunnel -type SHP candidate sites existing on Han-river were selected and surveyed for actual site reconnaissance. The performance characteristics and economical feasibility for these sites were analyzed by using developed models. As a result, it was found that the optimum design flowrate with the lowest unit generation cost for tunel-type SHP candidate site were the flowrate concerming with between 20% and 30% of time ratio on the flow duration curve. Additionally, primary design specifications such as design flowrate, effective head, capacity, annual averageload factor, annual electricity production were estimated and discussed for eight surveyed SHP candidate sites.

• 대한안전경영과학회지
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• 제13권2호
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• pp.185-193
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• 2011

The successful and sustainable growth of SMEs depends on their ability of strengthen their competitiveness in quality and cost and service more than anything else as a fundamental of operation. Among these key competitive factors of SMEs, quality is the most critical factor in manufacturing business fields. There are many different ways to improve the quality performance but it needs proper management decision to choose the best way what can maximize outputs with minimum inputs. And it needs effective measurement methods and some indicators to analysis the quality performance properly. The quality cost is one of the simplest key indicators to measure the quality performance and the effectiveness of quality related management decisions. In this study, through survey on local SMEs, we found that their average annual quality cost ratio versus turnover - total amount of annual quality cost divided by annual turnover - is around 3.69% excluded some SME's performances what have different quality control measures with others. And we found some results what corresponded with the early studies on the correlations between those categorized quality costs factors and some discrepancies between some of the literature model and the early case study results as follows. There were negative correlations between the Prevention costs and the External failure costs, and the Appraisal costs and the External failure costs, and there was positive correlation between the Appraisal costs and Internal failure costs same as early studies. But, we couldn't found any strong negative correlations between the Cost of control - Prevention costs & Appraisal costs - and the Cost of Failure of control - Internal & External failure costs -.

• 한국지열·수열에너지학회논문집
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• 제13권4호
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• pp.31-38
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• 2017

The heating and cooling air conditioning field has been increasing the problems of energy consumption and global warming in the world. A geothermal heat pump has been known as one of the highest efficient heating and cooling system. In this study, the analysis about the test standards of the geothermal heat pump of the Republic of Korea was executed. From the research, the following results were given. It is needed to address the domestic test standard for direct heat exchange geothermal heat pump. Water to air multi geothermal heat pump test standard was only developed in Korea. The test standard to calculate a seasonal energy efficiency ratio for cooling period and heat seasonal performance factor for heating period should be newly developed to estimate actual annual energy consumption and $CO_2$ emission.

• 농업과학연구
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• 제50권4호
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• pp.869-881
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• 2023

A genetic improvement program in Korea was implemented to improve the performance of Hanwoo cattle by generating livestock with genetically desirable economic characteristics. In particular, in response to external changes, such as the expansion of Free Trade Agreement (FTA), the livestock genetic improvement program has increased farm income by improving the productivity and quality of Hanwoo cattle. Using production cost data from Statistics Korea, the total input and output indices of Hanwoo feeding cattle from 2008 - 2021 were estimated and the growth and productivity changes were analyzed. The productivity change measures results were used to estimate the cumulative effects of the Hanwoo genetic improvement program on quality improvement, another purpose of the program, using a finite distributed lag model. The average annual increase in output (market weight) of Hanwoo was 0.9%. However, total input increased by 1.6%, resulting in a 0.6% decline in total factor productivity. In contrast, the Hanwoo genetic improvement program contributed significantly to the production of high quality beef, rather than contributing to improved productivity of the cattle. Hanwoo carcass weight, which is used as a performance indicator for the livestock genetic improvement program, has significantly improved and is projected to increase at a slower rate. The collective findings indicate the need for new performance indicators that can comprehensively indicate the performance of the genetic improvement of Hanwoo.