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        검색결과 176

        121.
        1991.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        현재 사용되고 있는 전개판의 성능을 보다 향상시키기 위한 방안으로 비행기의 익이론에 기초를 두고, 전개판의 경계층을 흡입하거나 제거하는 방법 중에서 역류역을 제거하는 와발생기의 부착을 전개판에 적용하였다. 성능분석을 위해서 단순만곡형, V-만곡형 그리고 슬롯만곡형 전개판의 3종에 와발생기를 부착하지 않은 경우와 부착한 경우에 대하여 성능 및 유체역학적 특성을 성능실험과 가시화실험을 통하여 비교해 보았다. 실험결과를 요약하면 다음과 같다. ① 단순만곡형전개판에 와발생기를 부착한 경우 최대전개력계수는 10~15% 증가, 항력계수는 2%미만증가, 양항비는 5~20% 증가하였다. ② V-만곡형전개판에 와발생기를 부착한 경우 양항비가 10~20% 증가하였다. ˚led3 슬롯만곡형에 와발생기를 부착한 경우 영각 20˚ 이내에서 최대전개력계수는 약 20%이상 증가, 항력계수는 5~20% 증가, 양항비는 약간 높게 나타났으나, 영각 25˚이상에서는 이들 계수의 값들이 기준형에 비하여 낮게 나타났다. ˚led4 와발생기를 부착한 전개판에서 박리점이 기준형에 비하여 다소 후연에 나타났다. ˚led5 와발생기에 따른 전.후면의 유속차는 단순만곡형의 경우 모든 영각에서 약 10% 증가, V-만곡형의 경우 전반적으로 증가하였으나 영각 25˚에서는 비슷하게, 슬롯만곡형의 경우 영각 25˚까지는 증가하는 것으로 나타났다. ˚led6 와발생기에 따른 박리역의 크기는 단순만곡형에서 약 5~15% 감소, V-만곡형과 슬롯만곡형은 영각 15˚~20˚에서는 약 10% 감소, 영각 25˚ 이상일 때는 비슷하게 나타났다.
        4,000원
        122.
        1991.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        현재 사용되고 있는 전개판의 성능을 보다 향상시키기 위한 방안으로 비행기의 익이론에 기초를 두고, 전개판의 경계층을 흡입하거나 제거하는 방법 중에서 역류역을 흡입하는 슬롯(slot)을 전개판에 적용하였다. 성능분석을 위해서 단순만곡형전개판에 슬롯이 없는 기준형과 슬롯의 위치에 따른 5종의 모형전개판에 대하여 성능실험과 가시화실험을 통하여 그 성능과 유체역학적 특성을 비교해 보았다. 실험결과를 요약하면 다음과 같다. ① 최대전개력계수는 0.6C, 0.4C, 기준형, 0.8C, 0.2C의 순으로, 슬롯의 위치 0.6C인 전개판이 영각 27˚에서 1.59로 가장 우수하였다. ② 항력계수는 슬롯의 위치가 후연으로 갈수록 감소하며, 슬롯을 준 경우가 기준형보다 작게 나타났다. ˚led3 양항비는 0.6C, 0.4C, 0.8C, 0.2C, 기준형의 순으로 모두 기준형보다 높게 나타났다. ˚led4 0.2C, 0.4C 및 0.6C의 전개판이 기준형과 0.8C의 전개판보다 박리가 후연에서 발생하였다. ˚led5 전개판의 전.후면에서 유속차는 영각 15˚~25˚까지는 점차 증가하고, 30˚에서는 감소하는 것으로 나타났다. ˚led6 박리역의 크기는 0.6C의 전개판에서 가장 적게 나타났다.
        4,000원
        123.
        2023.11 서비스 종료(열람 제한)
        The need for improved port call performance in African ports is way overdue as none of the African sea ports appear on the top 100 sea ports in the World as presented by the Lloyds list. The performance of ports greatly serves and benefits various stakeholders besides the country in which they belong. These stakeholders do include but not limited to third-party logistics providers, vessel/ship owners etc hence the need to improve port call performance is critical. There is not much studies available that tackle the issue of port call performance a hence creating a gap which this study opted to fill and contribute towards the assessment of Africa maritime trade contributors port call performance as most of the ports in Africa are deemed not efficient. Hence this analysis aimed at analyzing the performance of African top ten leading countries that contribute to the global maritime trade and later combine both African countries and the world’s top ten leading maritime trading countries as a benchmark to establish an improvement strategy from which low performing DMUs in the analysis were to borrow a leaf from. Having conducted the study, some African countries came out to be more performing. A few adjustments are to be made for them to improve their port call performance. However, their performance was still above average in comparison to the world’s leading countries that posed as benchmark and a standard port call performance operation strategy.
        124.
        2020.10 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The study examines the efficiency of private sector banks in India with the help of Window DEA (Data Envelopment Analysis) for a period from 2005 to 2017. With a window of three years, the period was divided into 11 windows. The study outcomes show that 59.9% of all private sector banks in India operate at more than 0.9 level of efficiency, and there are only three occasions when banks were operating at the efficiency value between 0.6 to 0.7. Further, the consistency in the efficiency scores of the banks has also been analyzed using an efficiency mapping matrix, and the mean efficiency score of the bank in each window is studied. The score of standard deviation was interpreted accordingly for these banks. Banks that are showing the highest efficiency scores also have a higher variance of efficiency scores. There was no bank identified in the matrix that promises high-efficiency ratings with low variability. The study concludes that the analysis of the efficiency mapping matrix indicates that, as a DMU escalates in the efficiency scores, the standard deviation reflecting the risk in overall efficiency scores also tends to rise. The findings complement the concept of higher risk to higher return or greater efficiency
        125.
        2020.08 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This research is defined as a study regarding on structured and systematized of existing literature review of the intersection between intellectual property management, management and technology transfer offices (TTOs). It takes a deeper look at requirements within universities, scientific institutions and the business environment should be interconnected with each other. The literature review shows that TTOs have control over the process of knowledge transfer and they have contributed to improving the efficiency of the use of production and human resources. In this paper, authors proposed the methodological tools based on methodology model, which identified success factors for using project management in TTO between two countries - Kazakhstan and Spain. Further, we used methodology is focused on solving the problems of quantitative analysis based on the use of primary data, which allowed us to reach a huge number of respondents without any restrictions, and secondary data from statistical database. Findings and results are summarized at the end of article show that Kazakhstan is following the path of the Spanish experience. However, Kazakhstan can become more successful in commercializing scientific technologies and transferring knowledge and technologies. In turn, Spain can use the data from our analysis to work on barriers and improve the activities of TTOs.
        126.
        2020.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This paper applies the Data Envelopment Analysis (DEA) to compute the managerial efficiency of 30 insurance companies listed on the Saudi stock exchange for the duration of four years from 2015 to 2018. The companies taken as a sample of study included both conventional and Takaful insurance companies. The insurance sector of KSA is one of the largest sectors in the country, contributing a substantial percentage in the non-oil economy. Efficiency measurement and evaluation will provide a venue to introspect and benchmark frontiers to the sector. In the present study, we have utilized the basic Banker Charnes Cooper and Charnes Copper Rhodes models of DEA. Two inputs, namely, general & administrative expenses and policy & acquisition costs, and two outputs (Net premium earned and Investment Income & other incomes) were taken for efficiency calculations. The final outcomes of the study reveal that a good number of insurance companies operating in KSA are found to be efficient on managerial efficiency scale. Three firms remain the leader on the frontier of the managerial efficiency. And no company found with zero (0) efficiency or a negative efficiency. It is expected that the outcome of the study will provide benchmarks to managers and a road map to further improvement.
        127.
        2020.06 KCI 등재 서비스 종료(열람 제한)
        This study analyzes the effect of negative air ions on the concentration of airborne particulate matter and evaluates the expected purification efficiency of open spaces for particulate matter by investigating the amount of negative air ions generated by plants. This study establishes a negative air ion generation treatment environment, plant environment, and control environment to measure the purification efficiency of particulate matter under the conditions of each, analyzing the expected purification efficiency by designing a particulate matter purification model. Results show that the amount of generated negative air ion according to environment was negative air ion generation treatment environment > plant environment > control environment; this order also applies to the particulate matter purification efficiency. Moreover, it took 65 min for the negative ion generation treatment environment, 90 min for the plant environment, and 240 min for the control environment to reach the standard expected purification efficiency of particulate matter concentration of 960 mg/m³ for PM10. For PM2.5, with the designated maximum concentration of 700 mg/m³, it took 60 min for the negative ion generation treatment environment, 80 min for the plant environment, and more than 240 min for the control environment. Based on these results, the expected purification efficiency compared to the control environment was quadrupled in the negative ion generation treatment environment and tripled in the plant environment on average.
        128.
        2019.09 KCI 등재 서비스 종료(열람 제한)
        Purpose - The self quality inspection which is mandatory in Republic of Korea can play an important role in promoting food safety, but the cost for self quality inspection is also a big burden especially for small businesses. In addition, excessive or duplicated inspection costs resulting from the standard gaps of various ministries and agencies ultimately effect negative social utility. Thus, this paper aims to suggest ways to improve the analysis of self quality inspection for the Ready-to-Eat Foods in terms of dried laver, in order to reduce costs caused by overinclusion. Research design, data, and methodology - The focus of interest is seaweed in Kimbab, which is to be exempted from the Vibrio parahaemolyticus test on the three grounds. First, existing literature provides little support for the necessity of performing a microbiological test. Second, laver products do not require the V.parahaemolyticus test by international standards such as the CODEX. Third, no case was found for seaweed products on the list of information on failed food items over the 2015~16 period. Results - Other types of seaweed such as exportable and seasoning seaweed are not subject to the test. Hence, exclusion of the V.pahaemolyticus test on seaweed is a valid point, bringing about large expected cost savings to many small businesses. Conclusions - Based on a complete survey of 75 food-testing agencies from March 20th to 30th, 2018, this paper finds that the proposed revision of the Kimbab test is likely to save an average of 130,000 won per business per year. Especially, in the case of the testing fee of Salmonella spp.(n,c,m,M), the cost difference by agencies was found to be up to five times. The regional gap in testing fees can be considered an unfair barrier. Accordingly, it is necessary to examine whether the testing fee is set at an appropriate level through the cost-extraction program proposed by the Ministry Food and Drug Safety. Hence, the survey results also point out that harmonization of testing fees charged by different food-testing agencies is appropriate with respect to transparency and efficiency.
        129.
        2019.08 KCI 등재 서비스 종료(열람 제한)
        정부는 국가 차원에서 물류인프라의 확충과 물류전문기업의 육성을 통해 물류기업의 경쟁력 향상과 국제물류시장의 주도권을 확보하기 위해 지속적인 노력을 실시해오고 있으며, 특히 동북아 지역의 경제규모 및 교역량이 자치하는 비중이 급증함에 따라 동북아 지역의 물류 네트워크 선정을 위해 다양한 정책을 추진하고 있다. 이러한 정부의 정책의 일환으로 2006년부터 종합물류기업 인증제도를 도입하여 시행하고 있다. 이 제도는 물류정책기본법에 근거하여 설립된 정부의 물류전문기업 육성방안의 대표적인 정책 중 하나이다. 그러나 이 제도로 인해 물류기업에 대한 신뢰성을 높여 물류산업의 선진화 및 효율화에 기여하였다는 주장과 동 제도로 인해 기업의 부담과 대기업 위주의 시장 통폐합 우려 등의 부정적인 의견이 대립되고 있다. 이에 본 연구는 이러한 논란이 있는 현 시점에서 종합물류인증 기업 중 물류창고기업을 대상으로 효율성 분석을 통해 비효율의 실태와 개선방안을 제시하고자 한다. 분석방법으로는 DEA 분석을 통해 종합물류인증기업의 경영효 율성을 분석하며 비효율적인 기업의 투사값을 제시하며 벤치마킹의 대상이 될 수 있는 기업들의 참조집합을 제시하고자 하며 또한 분석결과 를 통해 벤치마킹의 대상이 되는 기업들을 제시하였다.
        130.
        2019.01 KCI 등재 서비스 종료(열람 제한)
        Purpose - Urban agglomeration construction is one of national strategic plans to accelerate the development of industrialization and urbanization in China, which has threatened the eco-environmental quality at the same time. This paper selected the urban agglomeration in the middle reaches of the Yangtze River as the research area. Research design, data, and methodology - The the slack-based measurement (SBM) model considering undesirable outputs is applied to measure the eco-efficiency of this urban agglomerations during 2006-2015. Results - The empirical results show that average eco-efficiency of the urban agglomeration in the middle reaches of the Yangtze River is 0.595. Regional ecological development is unbalanced. The highest eco-efficiency is recorded at Wuhan Metropolitan Area, and the lowest one is at the Changsha-Zhuzhou-Xiangtan City Group. Energy consumption and waste dust emissions are the key factors led to ecological inefficiency. Based on this, potentials for energy saving and waste dust reducing are calculated. Conclusions - Finally, this study provides policy implications targeted to promote the coordinating development of economy and eco-environment under the construction of urban agglomeration.
        131.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        본 연구는 우리나라의 1990-2014년 시계열 자료를 활용하여 물 효율성, 경제성장, 전력생산 및 이산화탄소 배출 간의 장·단기 인과관계를 실증적 으로 분석하였다. 기존 연구들이 경제성장, 이산화탄소 배출 및 전력 및 에너지에 국한되어 분석을 한 반면 본 연구는 기존 변수들과 더불어 물 효율성과의 관계를 설명하였다는 기여를 가지고 있다. 실증분석결과를 살펴보면, 네 변수들은 단기조정관계를 통해 장기적으로 균형상태에 도달한다는 것과 변수들 간의 인과관계에서 이산화탄소 배출과 경제성장은 물 효율성의 원인이 되고 이산화탄소 배출과 경제성장 및 물 효율성은 전력생산의 원인이 된다는 사실을 발견하였다. 또한 물 효율성에 대한 장기 영향계수 추정결과를 통해 전력생산의 증가와 경제성장 및 이산화탄소 배출의 감소는 물 효율성을 증가시키며, 일정 수준 이상의 경제성장은 물 효율성의 증가속도를 감소시킨다는 경제성장과 물 효율성의 역U자형 관계를 확인하였다.
        132.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to examine the improvement plan by analyzing the characteristics of imported wastes, operation rate, and benefits of energy recovery for incineration facilities with a treatment capacity greater than 50 ton/ day. The incineration facility capacity increased by 3,280 tons over 15 years, and the actual incineration rate increased to 2,783 ton/day. The operation rate dropped to 76% in 2010 and then rose again to 81% in 2016. The actual calorific value compared to the design calorific value increased by 33.8% from 94.6% in 2002 to 128.4% in 2016. The recovery efficiency decreased by 29% over 16 years from 110.7% to 81.7% in 2002. Recovery and sales of thermal energy from the incinerator (capacity 200 ton/day) dominated the operation cost, and operating income was generated by energy sales (such as power generation and steam). The treatment capacity increased by 11% to 18% after the recalculation of the incineration capacity and has remained consistently above 90% in most facilities to date. In order to solve the problem of high calorific value waste, wastewater, leachate, and clean water should be mixed and incinerated, and heat recovery should be performed through a water-cooled grate and water cooling wall installation. Twenty-five of the 38 incineration facilities (about 70%) are due for a major repair. After the main repair of the facility, the operation rate is expected to increase and the operating cost is expected to decline due to energy recovery. Inspection and repair should be carried out in a timely manner to increase incineration and heat energy recovery efficiencies.
        133.
        2018.05 서비스 종료(열람 제한)
        To achieve energy efficiency improvement is used to lower temperature for emission gas at catalyst inlet, or to reduce/stop using steam to reheat emission gas. Saved energy from this process can be used as power source in order to increase generation efficiency. Dry emission gas treatment, on the other hand, is the technology to increase generation efficiency by using highly efficient desalination materials including highly-responsive slaked lime and sodium type chemicals in order to comply with air pollution standards and reduce used steam volume for reheating emission gas. If dry emission gas is available, reheating is possible only with the temperature of 45℃ in order to expect generation efficiency by reducing steam volume for reheating. Retention energy of emission gas from combustion is calculated by emission gas multiplied by specific heat and temperature. In order to obtain more heat recovery from combustion emission gas, it is necessary to reduce not only exothermic loss from boiler facilities but emission calorie of emission gas coming out of boiler facilities. In order to reduce emission calorie of emission gas, it is efficient to realize temperature lowering for the emission gas temperature from the exit of heat recovery facility and reduce emission gas volume. When applying low temperature catalysts, the energy saving features from 0.03% to 2.52% (average 1.28%). When increasing the excess air ratio to 2.0, generation efficiency decreases by 0.41%. When the inlet temperature of the catalyst bed was changed from 210℃ to 180℃, greenhouse gas reduction results were 47.4, 94.8, 118.5, 142.2 thousand tons-CO2/y, CH4 was calculated to be 550.0, 1100.1, 1375.1, 1650.1 kg-CH4/y, and N2O was 275.0, 550.0, 687.6, 825.1 kg-N2O/y. In the case of high efficiency dry flue gas treatment, reduction of greenhouse gases by the change of temperature 120~160℃ and exhaust gas 5,000 ~ 6,500 ㎥/ton is possible with a minimum of 355,461 ton/y of CO2 and minimum 4,125 tons of CH4/y to a maximum of 6,325 ton/y and N2O to a minimum of 2,045 kg/y to a maximum of 3,135 kg/y.
        134.
        2018.04 KCI 등재 서비스 종료(열람 제한)
        Planning strategies to achieve higher competitiveness of ports are becoming increasingly important in business environment. Therefore, strategic competitive position and efficiency analysis needs to be performed to increase ports’ effectiveness and competitiveness. This matches with one of targets of new concept e-Navigation to increase the agility and efficiency of ports. The purpose of this study was to apply Boston Consulting Group matrix to analyze competitive positioning of major ports in Korea and China in term of several main cargo types and then use a combination of Data Envelopment Analysis and Principal Component Analysis model to calculate efficiencies. Results show that, at the moment, Chinese ports are still on the top with high position and efficiency score for the representative-Shanghai port. However, result also points out that except container type, Korean ports have chance to compete in other cargo types. Moreover, Gwangyang port is regarded as efficient. It has better position time. It is believed that Gwangyang port together with Busan port can compete with Chinese port in the near future.
        135.
        2018.04 KCI 등재 서비스 종료(열람 제한)
        Since 2005 the landfilling of food waste has been prohibited, and many recycling facilities (private, domestic, animalfeed conversion, public composting) have been constructed and operated as waste-treatment centers. However, due to the negative attitude of users on the domestic animal feed and compost produced from food waste, the byproducts of waste have created a vicious cycle, needing treatment themselves. In addition, the London Convention prohibited the discharge of organic waste such as sewage sludge into the ocean in 2012 and of food-waste leachate in 2013. An alternative to landfilling and incineration is to treat biomass with anaerobic digestion. However, the anaerobic-digestion efficiency of the Daejeon City bioenergy facility, which has adopted a mixed digestion process of food waste and food waste leachate, has not been reproduced in other municipalities due to a misunderstanding of anaerobic digestion and a lack of operating skill. Thus, the anaerobic-digestion efficiency of the bioenergy facility in Deajeon is analyzed, and it provides basic information for the anaerobic co-digestion of organic wastes.
        136.
        2018.02 KCI 등재 서비스 종료(열람 제한)
        The paper aims to estimate efficiency of watermelon by using a bootstrapping approach to generating efficiency estimates through Monte Carlo simulation resampling process. We use the input-output data for watermelon 107 farmers. The main results are as follows. The estimates of efficiency depends on the methodology. The estimates of general DEA is greater than the bootstrapping method. The technical efficiency and pure technical efficiency measure of watermelon is 0.72, 0.82 respectively. However the bias-corrected estimates are less than those of DEA. We know that the DEA estimator is an upward biased estimator. According to these results, the DEA bootstrapping model used here provides bias-corrected and confidence intervals for the point estimates, it is more preferable.
        137.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        This study analyzes an economic efficiency of environmental friendly farm and conventional farm using the data envelopment analysis (DEA). We compare the economic efficiency of Environmental Friendly farm and Conventional farm. We also analyze the effects of some explanatory variables on allocative efficiency (AE), pure technology efficiency (PTE) and scale efficiency (SE). In the case of strawberries farm, environmental friendly farm has higher overall efficiency (OE) than conventional farm. But tomatoes farm has higher overall efficiency (OE) than conventional farm. And We measure returns to scale of farms. Most strawberries and tomatoes farms showed Increasing to Scale (IRS).
        138.
        2017.11 서비스 종료(열람 제한)
        Depending on the steam pressure and temperature balance, it is possible to increase the power generation efficiency of the steam turbine by increasing the heat loss of the turbine by increasing the temperature and pressure. As the high temperature and high pressure increase, the boiler main steam amount is reduced by about 10%, but the increase rate of the heat drop is larger than the decrease rate of the steam flow rate, leading to improvement of power generation efficiency. Utilizing the US Department of Energy Steam Turbine Calculator, we calculated the electricity produced by steam temperature and pressure changes. In this study, the steam temperature was increased from 50℃ to 500℃ at the steam temperature of 20 kg/cm²×300℃, and increased by 10 kg/cm² at the pressure of 20 kg/cm² at the pressure of 60 kg/cm² to investigate the changes in electricity production. Electricity production increased with increasing temperature and pressure. The electricity production was increased by 40.11% at 40 kg/cm²×400℃ and 75.56% at 60 kg/cm²×500℃ compared to the standard condition of 20 kg/cm²×300℃ for comparison.
        139.
        2017.11 서비스 종료(열람 제한)
        Energy can be reduced by reducing the exhaust gas temperature at the catalyst inlet and reducing or not using the amount of steam to reheat the exhaust gas. At this time, it is a method to improve the power generation efficiency by using the saved energy for power generation. When the exhaust gas temperature at the inlet of the catalytic reaction tower is operated at about 210℃, it is necessary to increase the temperature of the flue gas downstream of the bag filter at 165℃ to 45℃ to 210℃ required for the catalytic reaction. In the case of low temperature catalyst application, the temperature required for the catalytic reaction tower may be 185℃ and the temperature may be raised only 20℃. Therefore, the amount of steam for heating can be reduced. If the exhaust gas temperature of the bag filter inlet can be increased to 190℃, it can be combined with the low-temperature catalyst to reduce the energy consumed by removing exhaust gas ash. On the other hand, since the high-pressure steam is used as the heat source for reheating the exhaust gas, the reheating temperature is limited. According to such conditions, the exhaust gas temperature at the inlet of the catalytic reaction tower is often designed at about 200 to 220℃.
        140.
        2017.10 KCI 등재 서비스 종료(열람 제한)
        Purpose – The domestic liquor market is steadily increasing, but locally made liquor markets remain stagnant. The market opening due to the FTA and westernized eating habits are expanding the consumption of imported liquor by Koreans and the demand for beer and soju is still high. Therefore, we analyzed the scale efficiency of Korean locally made liquor companies. Research design, data, and methodology – Based on a translog-cost function, a scale efficiency analysis was conducted using the government’s information survey on the liquor industry. Data from 541 liquor companies analyzed from 2013 to 2014 were used for analysis. Results – As a result of the scale efficiency analysis, the average sales of the mid-sized locally made liquor companies is 171 million won, but the appropriate sales amount is 1 million won. It is estimated that there is a need to increase sales. Conclusions – The gap between the actual sales and the appropriate sales of mid-sized locally made liquor companies with 3~10 employees is larger, so it is necessary to reduce the average cost by increasing the sales of locally made liquor companies. In order to do so, it is necessary to acquire customer strategies such as product differentiation, advertising and publicity.
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