• Korean Journal of Mathematics
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• 제20권3호
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• pp.323-331
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• 2012

We present a high-order potential ow model for the motion of the impulsively accelerated unstable interface of infinite density jump. The Layzer model for the evolution of the interface is extended to high-order. The time-evolution solutions of the bubble and the spike in the interface are obtained from the high-order model. We show that the high-order model gives improvement on the prediction of the evolution of the bubble and the spike.

• 한국기계연구소 소보
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• 통권14호
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• pp.17-31
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• 1985

The Primary object of this study is to predict rigid carbody's vertical and pitch acceleration and/or displacement frequency response to vertical sinusoidal rail surface irregularities for any specified point of the carbody, and to verify the predictions by means of experiments. The developed computer program also calculates vertical and pith transmissibilities and acceleration spectra. This model can be used for first order analysis of ride behabior. it's main advantage is its simplicity and ease of use. This model can be used for first order analysis of ride quality behabior. It's main advantage is its simplicity and ease of use. The model was designed with 6 degreed of freedom. Equations of motion were derived by Lagrangian method. This calculation was applied to the vertical dynamic analysis in order to pursue a possible improvement of the dynamic performance of co-co locomotive, and results were very useful.

• 품질경영학회지
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• 제37권3호
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• pp.123-139
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• 2009

This study examines the relative efficiency of 34 local public medical centers in Korea. In order to concretely grasp the causes of inefficiency and suggest improvement solutions, the desirable set point was established based on the actual value which needs to be improved. As a result of analysis, we determined that output must be increased while input is held constant in order to improve effectiveness through the actual value and set point. Efficiency cannot be achieved if input is augmented solely to increase output. Also, to increase output, the medical centers need to improve their quality without increasing any input for customer visits and hospitalizations. Further, in order to strategically promote effectiveness and efficiency of local public medical centers, these medical centers must focus on input resource and patient interchange through the mutual cooperation with local private hospitals and university medical centers.

• Korean Membrane Journal
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• 제2권1호
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• pp.48-55
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• 2000

In order to improve organic vapor separation efficiency of polydimethylsiloxane (PDMS) membrane, various zeolites (zeolite 4A, zeolite 13X and natural zeolite) were introduced into a thin PDMS film. The measurements of permeability and selectivity of zeolite-filled PDMS membranes were carried out with a CO$_2$gas and a CO$_2$gas/acetic acid vapor mixture, respectively. The CO$_2$permeability of zeolite-filled membranes decreased with increasing zeolite content and then recovered up to 30 wt% content. The effect of zeolite type on the improvement of CO$_2$permeability was found to be in the order of zeolite 13X > natural zeolite > 4A. The CO$_2$selectivity of zeolite-filled membranes was enhanced up to 9 times compared with the selectivity of a pure (unfilled) PDMS membrane. The effect of zeolite type on the improvement of CO$_2$selectivity was found to be in the order of natural zeolite > zeolite 13X > zeolite 4A.

• 제어로봇시스템학회논문지
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• 제12권8호
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• pp.739-745
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• 2006

This paper presents performance improvement of the INS velocity-adided GPS carier tracking loop. To this end, INS velocity-aided GPS carrier tracking loop was modeled as a feedfoward and a feedback loop system. In the phase tracking loop, it was shown that the tracking error caused by the dynamic motion of the vehicle can be compensated with the aiding of the INS information irrespective of the loop order and bandwidth. However, the signal trcking error increases as the INS error increases. It was also shown that in order to remove the tracking error caused by INS bias error, more than or equal to 2nd order PLL should be used. Experiments were carried out and the experimental results were compared with the analysis results.

• Journal of electromagnetic engineering and science
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• 제13권4호
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• pp.263-266
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• 2013

A novel compact and low-loss VHF bandpass filter is presented with enhanced stopband performance using metamaterial zeroth order resonator (ZOR) characteristics. An in-line ZOR filter is initially suggested and changed to have transmission zeros (TZs) due to source-load coupling for effective improvement of the isolation from UHF wireless channels. The proposed filter is smaller than 1/10 of the conventional filters in terms of size and has relatively very low insertion loss (< 1 dB for the electromagnetic (EM) simulation and < 3 dB for the measurement) and return loss (<-20 dB) in the passband due to the approximately 80% size reduction and the higher isolation in the stopband due to the TZs. The circuit and EM simulation are in good agreement with the measurements.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.67-68
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• 2018

In the public sector, the number of interior construction projects is continuously increasing. When the interior construction is carried out, it is largely divided into design and construction stages. On the other hand, in order to place an order in the public sector, it requires institutional conditions such as business type, price criterion, award criteria, and guarantees. But in th case of interior design, it is necessary to establish a basis law to be applied for ordering. Therefore, this study analysed the necessity of improving the system related to the interior design order in the public sector and suggested ways to improve the system. In the future, we will continue to conduct research based on this research, and if institutional improvement is made through the proposed methodology, it will be possible to apply effectively not only in the public sector but also in the private sector.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.609-613
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• 2011

The importance of project performance management as an alternative for solving problems is rising, which are followed by the difficulties of managing construction project in the construction industry. This research classifies and applies the potential improvement made by the construction practitioners. In order to apply influential factors for success on the construction project, the research identifies the relationship between the factors and performance management practices. In addition, in order to predict the results reflecting the project characteristics which are un-improvable by the construction managers in the initial stage of construction, the effect of project characteristics to the identified management practices have been drawn by performance area. Finally, in order to improve the predicted performance, this research provides a framework in setting valid best practices according to the performance areas through a statistical analysis between the best practices and project characteristics through the industry survey.

• 한국전자통신학회논문지
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• 제16권5호
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• pp.899-908
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• 2021

현대의 무기체계는 복잡한 체계로 구성되어 있기 때문에 성능개량 요소의 우선 순위를 도출하는 것은 상당한 어려움이 있다. 또한, 이해관계자들의 의견을 고려한 정량적 성능개량 요소 우선순위 선정 방법론에 대한 연구도 미흡한 실정이다. 본 연구에서는 K1계열 전차와 K2전차의 성능개량 요소 우선순위를 정량적으로 도출하기 위해 전차 개발 경험을 보유한 전문가들을 대상으로 설문을 수행하고 AHP, 평점법, TOPSIS 기법을 이용하여 서문 데이터를 분석하고 분석 결과로 우선순위를 정량적으로 도출하였다. 본 연구의 결과는 향후 무기체계 개발 및 성능개량 단계에서 이해관계자들의 의사결정 지표로 활용될 것으로 기대된다.

• 한국주거학회논문집
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• 제10권4호
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• pp.63-70
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• 1999

The purpose of this study is to evaluate the outdoor environmental quality level at the improvement areas of residence and examine the changes of these areas where the improvement process has been performed. The indicators of outdoor space were examined for case study and several improvement areas were selected and analyzed in terms of these indicators. The improvement areas may be divided into two branch, one is a housing improvement area and the other is a multi-family housing area. The results of this study were as follows; 1) Land-use intensity in both cases was much higher than before. 2) Open space ratio in the housing improvement areas was not enough but in the multi-family housing areas was enough. 3) The road ratio in both cases was much higher. 4) Parking space was not enough to accomodate all the cars in projects. 5) Public facilities and green space did not exist in housing improvement areas but existed a little in multi-family housing areas. In order to improve the environmental quality level, the proper residential density such as dwelling density, open space ratio, land-use intensity should be planned in advance.