• Korean Journal of Construction Engineering and Management
• /
• v.9 no.3
• /
• pp.185-193
• /
• 2008

In order to improve work efficiency in high-rise apartment building construction, it is required to establish the major criteria and practical method for selecting the construction lifts. It is necessary to analyze work efficiency and economic feasibility depending on speed, size and capacity of lifting equipment and characteristics of construction projects. The purpose of this research is to develop the fundamental process and information for selecting the lift in order to plan and manage the material lifting and laborers' vertical transporting in the high-rise apartment building projects more effectively. In order to satisfy the objective of the research, work performance of the lifting machines with different speed and carrying capacity is analyzed under the practical constraints. In addition, potential economic evaluation is conducted. One of the significant findings of the research is that the mid-speed lift shows 43% improvement in work efficiency compared with the low-speed lift. The results of the research will be used as the basis for developing the further optimal lifting management system.

• Environmental and Resource Economics Review
• /
• v.30 no.3
• /
• pp.471-501
• /
• 2021

We measure Environmental Efficiency (EE) based on CO₂ in four income groups from 1998 to 2018, using the Meta Stochastic Frontier Analysis method by Input Distance Function. Our results showed that economic growth and energy consumption would increase carbon dioxide emissions, and increasing labor and capital input will reduce it. Moreover, we compared Group Environmental Efficiency (GEE), Meta Environmental Efficiency (MEE), and Environmental Gap Ratio (EGR). The results showed that GEEs were be overestimated. Furthermore, the MEE showed a downward trend during this period. The lower-middle-income group had the highest EGR performance. High-income and upper-middle-income groups showed less efficiency in MEE and EGR. To improve environmental efficiency, we must reduce fossil fuels and find more scientific and technological ways to solve existing environmental problems as soon as possible.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.5
• /
• pp.60-68
• /
• 2020

Owing to the complexity and modernization of weapon systems, the role of the defense industry in producing military companies has become increasingly important. In the past defense industries, price competitiveness is a key factor in product choice. On the other hand, product quality is becoming increasingly important compared to price competitiveness. In particular, improving the quality efficiency of small and medium defense suppliers is a necessary part of realizing completed weapon systems, and measures are required to evaluate the quality efficiency of small and medium defense suppliers objectively. This study measured the efficiency of quality using DEA, which is one of the decision methodologies. To use DEA, the number of employees (QA Team) and the number of improvement requirements (Through the activity of onsite quality-support team in aeronautical system center) were set as the input variables. In addition, the output variables were based on sales and the number of certification acquisitions (QMS). To analyze the quality efficiency of small and medium defense suppliers in the aeronautical field, both CCR and BCC models were analyzed, and the scale efficiency values were derived. Strategic development plans for small and medium defense suppliers can be guided using the research results.

• Journal of Environmental Policy
• /
• v.11 no.4
• /
• pp.131-154
• /
• 2012

Existing researches on tax efficiency of environmental taxes mostly focuses on taxes imposed on the consumption process of the final output, or goods that create pollution during the input process of intermediate goods. The assumption here is that there is a significant relation between the consumption of polluting goods and the pollution itself. However, in reality they are not identical. This signifies that the above assumption may distort the actual results. This study classifies environmental tax into two different forms, output tax and emission tax. Theformer is the tax that is imposed on the consumption of polluting goods, while the latter is directly levied onto the emission of pollution. It then compares the efficiency of these taxes through the computational general equilibrium simulations. After analyzing the simulation, it was proven that the direct imposition on pollution, or environmental tax as emission tax, was more effective in terms of tax efficiency. Furthermore, these results were revealed as irrelevant to the assumption of homotheticity in utility function. Thus, if market-distortionary tax already exist, then the effectiveness of revenue neutral environmental tax reform will be sensitive to the assumption of homotheticity for utility function. However, environmental taxes as emission taxes have been shown to be more effective in tax efficiency than output taxes.

• Journal of KIISE:Software and Applications
• /
• v.30 no.12
• /
• pp.1185-1192
• /
• 2003

In the component assembly and composition technique of software architecture, It is operated that the existing composition techniques based on architecture, ACME, Wright etc., used in FIFO with the direct connection structure between components through connector's Role. But, when the non-synchronizing request of components that have different characteristics occurs, the FIFO techniques is applied to the connector is difficult to process and operate effectively because of the high performance component waiting the sequence order if the low performance component is allocated first. Thus, the allocated request process according to the priority considering the characteristics of each call components in connector is necessary to improve the operation of assembled component. In this research, we extend the connector part that is available in multiplex connection structure based on existent Wright specification. For service process requested from component, the connector part is designed and implemented to operating with priority sequence through calculating the weight of CPU use rate, bean requesting process time and memory use rate among the efficiency elements of assembled components. To verify the efficiency if this designed connector, we implemented 20 samples EJB components that have different efficiency characteristics and applied these samples components to designed connector. The operating results with this designed connector show that the efficient operation of whole system is possible though the processing time takes 481ms more than the time of the existing FIFO techniques.

• Journal of Wetlands Research
• /
• v.23 no.1
• /
• pp.60-66
• /
• 2021

As the concentration of nitrogen in the sewage flowing into the sewage treatment plant increases due to urbanization and industrialization, the degree of adverse effects such as eutrophication and toxicity to the aquatic ecosystem is also increasing. In order to treat sewage containing high concentration of nitrogen, various studies on the biological nitrogen removal process are being conducted. Existing biological nitrogen removal processes require significant costs for supplying oxygen and supplementing external carbon sources. In this respect, as a high-level nitrogen removal process with economic improvement is required, an anaerobic ammonium oxidation process (ANAMMOX), which is more efficient and economical than the existing nitrification and denitrification processes, has been proposed. The purpose of this study is to confirm the stability of the ANAMMOX process in the water treatment process and to derive the ratio of ammonia nitrogen (NH4+) to nitrite nitrogen (NO2-) for the implementation of the mainstream ANAMMOX process. A laboratory-scale Mainstream ANAMMOX reactor was operated by applying the ratio calculated based on the substrate ratio suggested in the previous study. In the initial range, the removal efficiency of NH4+ was 58~86%, and the average removal efficiency was 70%. In the advanced range, the removal efficiency of NH4+ was 94~99%, and the average removal efficiency was 95%. As a result of the study, as the NH4+/NO2- ratio increased, the stability of the mainstream ANAMMOX process was secured, and it was confirmed that the NH4+ removal efficiency and the total nitrogen (TN) removal efficiency increased. As a result, the results of this study are expected to be used as basic data in the application of the ANAMMOX process in the mainstream.

• Annual Conference of KIPS
• /
• 2014.11a
• /
• pp.613-616
• /
• 2014

오늘날 선박, 항공, 자동차산업 등의 복합화로 인하여 내장형 소프트웨어의 중요성이 크게 대두되고 있다. 중요도가 높아질수록 고장 현상 발생률이 증가하고 이에 따른 오류나 고장에 대한 영향도 급증 하기 때문에, 신뢰성이 그만큼 중요하게 되었다. 신뢰성은 ISO/IEC 9126, ISO/IEC 12119 등에서 기능성, 사용성, 효율성, 유지보수성, 이식성과 함께 언급되고 있다. 신뢰성의 부특성에는 성숙성, 오류허용성, 회복성, 준수성이 있고, 이에 따라 품질평가 항목 메트릭이 제시되어 있다. 그러나 신뢰성 평가 기준은 수리적 난해함과 데이터 수집에 관한 문제에 부딪혀 적용하는 데에 어려움이 따르는 실정이다. 이와 같은 문제점을 해결하기 위해, 각 세부 평가 항목에 대한 체크리스트를 가지고 품질평가 메트릭에 적용하였다. 또한, 기존에 제시되어 있는 대표적인 신뢰성 모델 두 가지 NHPP(Non-Homogeneous Poisson Process) Model과 Jelinski-Moranda Model을 성숙성과 오류허용성의 품질평가 메트릭과 연관시켜 효율적으로 신뢰성을 측정하는 방안에 대하여 모색하였다.

• Proceedings of the CALSEC Conference
• /
• 1998.10a
• /
• pp.27-43
• /
• 1998

Recently, most corporations in Korea need to construct new management system for overcoming economic crisis. Firstly, this paper suggests “Value Creation system”. Secondly, this paper suggests CALS as strategic substitute to achieve market efficiency, capital efficiency, personal efficiency, and operation efficiency, which are four critical factors of “Value Creation system”. Korean corporations should build new business model founded on cooperation by completing CALS system and reconstruct competitive management system by using knowledge and know-how accumulated in that process. Because most corporations keep exclusive corporate culture and little experience of cooperative relationship among businesses, strategic approaches are essential for construction of CALS. These are vertical integration, organization of CALS construction teams, concurrent development of product/process, CEO's iron will, Precise vision and strategies, and education/training of participant.

• Journal of Digital Convergence
• /
• v.11 no.8
• /
• pp.31-39
• /
• 2013

Recently, integration between social media and the industry has been expended, and as the usage of Internet through various smart devices of not only the existing PC but also smart phone, tablet PC and so on, a lot of unstructured data has occurred, leading to increased interest on big data system. According to the institutes which specialize in market research, the data amount is predicted to increase by 9 folds in the next 5 years when compared to the present, and the big data market is also expected to grow bigger. This dissertation evaluates the efficiency test of big data through analysis on the requirements by identifying and fragmenting the items of efficiency quality evaluation that big data should be equipped with.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.6
• /
• pp.1585-1592
• /
• 2016

Estimation of winning percentage in baseball has always been particularly interesting to many baseball fans. We have fitted models including linear regression and Pythagorean formula to the Korean baseball data of seasons from 1982 to 2015. Using RMSE criterion for both the linear formula and the Pythagorean formula, we compared two models in predicting the actual winning percentage. Pythagorean expectation is superior to linear formula when there is either high or low winning percentage. Two methods yield very similar efficiencies when the actual winning percentage is about 50%. To understand and use for estimating winning percentage, it is easier linear formula as estimated equations.