• Journal of Advanced Marine Engineering and Technology
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• 제36권4호
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• pp.476-483
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• 2012

본 논문에서는 선외기에 적용되는 5HP급 전동 추진시스템의 효율 개선 방안에 대해 고찰하였다. 추진시스템의 핵심 부품인 전동기 및 프로펠러의 최적 효율 개선 모델을 제안하고 시제품 제작을 통하여 개선 모델의 특성을 검증하였다. 또한 실장착 시험을 통해 기존 추진시스템 대비 20% 이상의 효율 개선효과를 입증하였다.

• 전기학회논문지
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• 제57권9호
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• pp.1536-1545
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• 2008

In this paper, we research a new method for efficiency improvement of a single-phase Induction motor by minimization of the stator loss. To make this, we perform winding design which is based on balanced and quasi-balanced operation condition. It gives efficiency improvement greatly but poor starting torque simultaneously. To obtain the best efficiency improvement maintaining the maximum and starting torque, the optimal winding specification and rotor dimension is determined with variation of secondary resistance, running capacitor and turn ratio. Finally, this paper gives the comparison between the simulation results and experimental results.

• Asian-Australasian Journal of Animal Sciences
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• 제12권8호
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• pp.1316-1323
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• 1999

Extensive emphasis on milk and milk fat yields with no diversion for beef performance increased the yield efficiency of North American dairy cattle. Heavy demand for North American genetics followed national strain comparison trials in Poland, and US and Canadian dairy cattle and germplasm still are an important source of genetics for many countries. Genetic improvement has accelerated in many countries because of the implementation of sampling programs for young bulls and improved evaluation procedures. Rapid access to information and more frequent calculation of genetic information also are having a positive impact on genetic improvement. Traits other than yield should be considered in a breeding program, but those traits mist have a reasonable opportunity for improvement and sufficient economic worth. Because of ever increasing efficiency, the world's milk supply comes from fewer cows each year. However, no decline in the rate of genetic improvement is apparent under current genetic practices; estimates of heritability are increasing, and a decline in yield efficiency is unlikely in the near future. As management improves, especially for subtropical conditions, many of the selection principles used in temperate climates will be adopted for more adverse environmental conditions.

• 한국전기전자재료학회논문지
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• 제21권6호
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• pp.569-574
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• 2008

In the device structure of ITO/tris(8-hydroxyquinoline) aluminum ($Alq_3$)/Al device, we investigated the efficiency improvement of organic light-emitting diodes (OLEDs) depending on the hole-size of crucible boat. The device was manufactured using a thermal evaporation under the base pressure of $5{\times}10^{-6}\;Torr$. The $Alq_3$ organics were evaporated to be 100 nm thick at a deposition rate of $1.5\AA/s$, and in order to investigate the optimal surface roughness of $Alq_3$, the $Alq_3$ was thermally evaporated to be 0.8 mm, 1.0 mm, and 1.5 mm as a hole-size of the boat, respectively. We found that luminance and external quantum efficiency are superior when the hole-size of the boat is 1.0 mm. The external quantum efficiency of the device made with the hole-size of 1.0 mm boat were improved by a factor of ten compared to the devices made with the hole-size of non boat.

• 산업경영시스템학회지
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• 제30권2호
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• pp.67-74
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• 2007

The objective of this research is to select the most effective technique among task related techniques(motion & time study, job redesign, physical environment improvement) for improving work efficiency in shipbuilding enterprise. This study consists of several principal steps. The first step is to design critical criteria in evaluating work efficiency in ship-building enterprises. The second step is to develop sub-criteria of the critical criteria. The third step is to develop a four level AHP(Analytic Hierarchy Process) structure using the critical criteria, sub-criteria and techniques among task related techniques. The fourth step is to develop the pairwise comparison matrix at each level of AHP structure, which was based on survey data collected at the H heavy industry. And the last step is to select the most effective technique among task related techniques using AHP analysis. The result of AHP analysis has shown clear difference in priority among task related techniques in terms of work efficiency of the shipbuilding enterprise: The reduction of normal time is more important than the reduction of allowance time in improving of the work efficiency. Motion & time study is the most important technique for the reduction of normal time, and physical environment improvement is the most important technique for the reduction of allowance time as well.

• 음성과학
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• 제7권3호
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• pp.229-247
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• 2000

The purpose of this study is to examine the improvement effect of articulation of the fricative consonant /s/(ㅅ), when applying the Articulation Modification Program (AMP) to hearing disordered students. Three hearing disordered students were selected for this study by the consonant picture and Korean Articulation Sentence tests. They have no defect in their emotion, behavior and sight. This program applied the multiple baseline design across subjects to examine the improvement effect of articulation of fricative consonant /s/(ㅅ). Also I designed th$\sim$s program with an advanced pre-test and post-test in order to research the improvement difference of articulation by articulation position and language unit. It was executed 32 sessions over three months, four sessions a week, one session taking forty minutes. The results according to the study subject are as follow; First, as result of AMP, articulation of all students was developed after applying this program. Second, as result of AMP, articulation in fore-word was one-hundred percent efficiency and articulation in middle-word was 97.7% efficiency by position. Third, as result of AMP, articulation in the word reached 98.7% efficiency, in phrase 97.7% efficiency, in the sentence 97.7% efficiency and in the story was 98.3% efficiency by language unit.

• 경영과학
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• 제27권2호
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• pp.45-54
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• 2010

In this paper we analyze the effects of loading-unloading environments on the efficiency of freight railroad stations using a two-stage procedure for efficiency model estimation. And from the results we explore a way for efficiency improvement of freight railroad stations. Two-stage procedure is composed of data envelopment analysis and regression analysis. The results show that we could expect efficiency improvement through the government"s effort to make railway stations to be strategic position. Furthermore, they advocate policy-makers that efficiency can be improved by simplifying the kinds of freight items and increasing the scale.

• 시멘트 심포지엄
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• 1호
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• pp.50-55
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• 1973

Improvement of grinding efficiency about open circuit grinding mill in cement production was investigated and the results were as follows; 1. Controlled the steel ball by charging ratio. 2. Raised the slot ratio from 3$\%$ to 4.5$\%$

• 산업경영시스템학회지
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• 제17권30호
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• pp.81-87
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• 1994

Productivity relates output to input and also integrates performance aspects of quality, efficiency and effectiveness. Productivity improvement are associated with efficiency and effectiveness, productivity index involved quality and flexibility, integrated productivity measurement system, and other factors. This study focused on the productivity improvement that involved the opportunity costs such as qualify costs and flexibility effects.

• 한국항공운항학회지
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• 제29권3호
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• pp.44-51
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• 2021

PIP is an abbreviation of 'Performance Improvement Package', which is a package that can improve performance by applying some design changes to existing aircraft. Boeing provides PIP applicable to B777-200, and Airbus provides PIP applicable to A350-900 as standard. PIP provided by Boeing and Airbus is a separate task, but it is expected to reduce fuel consumption by reducing drag through aerodynamic improvements. The PIP applied to the A350-900 includes work such as increasing Winglet Height and re-twisting Outboard Wing. This study is to verify the effect of PIP application of the A350-900 aircraft and use it as basic data for economic analysis. The aerodynamic improvement studies and expected effects of the PIP application were examined, and the actual flight data of the PIP-applied and the non-applied aircraft were compared to confirm the PIP application effect. This paper provides empirical results for the aviation industry on the PIP application efficiency as a method of improving fuel efficiency and reducing carbon emission.