• 한국초전도ㆍ저온공학회논문지
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• 제19권3호
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• pp.1-7
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• 2017

It is required to reduce the cost of superconducting cable to realize a superconducting DC power network that covers a wide area in order to utilize renewable energy. In this paper a new concept of innovative cable is introduced that can enhance the current-carrying capacity even though the same superconducting tape is used. Such a cable can be realized by designing an optimal winding structure in such a way that the angle between the tape and magnetic field becomes small. This idea was confirmed by preliminary experiments for a single layer model cable made of Bi-2223 tapes and REBCO coated conductors. Experiments of three and four layer cables of practical sizes were also done and it was found that the current-carrying capacity increased as theoretically predicted. If the critical current properties of commercial superconducting tapes are further improved in a parallel magnetic field, the enhancement will become pronounced and this technology will surely contribute to realization of superconducting DC power network.

• 한국항공운항학회지
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• 제13권3호
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• pp.22-33
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• 2005

Response Surface Method (RSM) constructs approximate response surfaces using sample data from experiments or simulations and finds optimum levels of process variables within the fitted response surfaces of the interest region. It will be necessary to get the most suitable response surface for the accuracy of the optimization. The application of RSM plan experimental designs. The RSM is used in the sequential optimization process. The first goal of this study is to improve the plan of central composite designs of experiments with various locations of axial points. The second is to increase the optimal efficiency applying a modified method to update interest regions.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.479-482
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• 2002

The purpose of this paper is to present and discuss some of evaporation and desiccation observed in field experiments. Surface desiccation of dredged material is basically changed by evaporation characteristics which is controlled by weather and ploughing interval, etc. This study shows that ploughing interval is important factors in desiccation of dredged soft clay. A series of field experiments with variation of ploughing interval were carried out to get evaporation effiency and strength increase. In this study, it is proposed that ploughing technique on the total surface area expedites surface desiccation efficiency. Desiccation efficiency is improved when ploughing technique is applied on the surface area.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.103-108
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• 1999

A problem in the grinding with a small diametric wheel is the decrease of wheel speed. In order to resolve this problem, an accelerating unit which increases the wheel speed is recommended. In this paper, the accelerating effect of an accelerating unit has been investigated through the side-cut grinding experiments performed with a vitrified bonded CBN wheel in a machining center(MC). The static stiffness, normal force, and machining error were measured in the experiments. As the accelerating unit is attached on the column of machining center, the static stiffness of tool system is largely decreased. But as the wheel speed increased by the accelerating unit, this problem is overcome and machining efficiency is improved. The lesser the quill stiffness was, the higher the accelerating effect became.

• 대한기계학회논문집
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• 제18권1호
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• pp.34-43
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• 1994

In order to improve thickness profile of cold rolled steel strip, a computer simulation and actual cold rolling experiments on a 4-high tandem cold mill were carried out. In this study, tapered barrel end at top work roll and incurved barrel body at bottom work roll were examined for reducing edge drop and threading of stripe. Also, the most effective stand of tandem cold mill and magnitude of optimal taper crown at several stand were investigated under a typical rolling condition. From actual rolling experiments, it was verified that thickness deviation over strip width could be improved up to 1.06% by applying tapered and incurved work roll only at the second and up to 0.89% by applying them at both the second and the third stand.

• 한국정보통신학회논문지
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• 제11권10호
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• pp.1944-1949
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• 2007

본 논문에서는 3차원 집적 영상 기술에서 렌즈 모델에 기초하여 3차원 물체에 대한 새로운 평면기반 컴퓨터 재생 방법을 제안한다. 제안하는 방법에 대해서 여러 시험 영상에 대해서 컴퓨터 실험을 수행하여 재생된 영상에 대한 해상도를 분석하고 기존의 방법에 의한 결과와 비교를 하였다. 실험 결과로부터 제안하는 방법을 사용함으로써 재생되는 3차원 영상의 해상도가 향상됨을 보였다.

• Journal of Positioning, Navigation, and Timing
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• 제7권4호
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• pp.205-215
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• 2018

The recent emergence of new Global Navigation Satellite Systems (GNSS) has resulted in a gradual improvement in the performance of positioning services. This paper verifies the degree of improvement in positioning performance of Assisted-GNSS (A-GNSS) receivers using assistance information compared to standalone-GNSS receivers that do not use assistance information in various urban environments in Korea. For this purpose, field tests are performed in various urban and indoor environments in Korea. The assistance information is provided by u-blox's AssistNow Online and low-cost commercial receivers are used for mobile station receivers. Through experiments, the Time to First Fix (TTFF), acquisition sensitivity, and position accuracy performance improvement are analyzed. The results of the experiments show that using assistance data improved the performance in all experiment locations, and, in particular, a significant performance improvement in terms of TTFF.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2019년도 제60차 하계학술대회논문집 27권2호
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• pp.267-270
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• 2019

Through this research, the rating data of shops were analyzed. The model was designed for discrete multiple classification as to the corresponding data, and the following experiments were initiated to observe the learned machine. By comparing each benchmarks in the experiments, which contains different setting variables for the machine model, the hit ratio was measured which indicates how much it is matched with the expected label. By analyzing those results from each benchmarks, the model was redesigned one time during the research and the effects of each setting variables on this machine were clarified. Furthermore, the research result left the future works, which are related with how the learning could be improved and what should be designed in the further research.

• 대한인간공학회지
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• 제1권2호
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• pp.3-9
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• 1982

This study demonstrates that certain personal and task factors can be modelled to predict slip potential as well as back loadings durings dynamic pushing and pulling tasks. Such tasks are com- mon to many manual material handling jobs in industry and the results of this work will hopefully be of use in improved job design. The objective of this research is to formulate and validate a dynamic biomechanical model of pushing and pulling a cart. For pushing and pulling tasks, the model can : (1) estimate foot forces for given hand forces, and (2) estimate tors muscle and vertabral column loadings. In order to formulate and validate the model, experiments involving pushing and pulling of a cart were performed. These experiments produced data of the following type : (1) dynamic forces on the feet, (2) hand forces required to move the cart, (3) body motions as functions of various cart motion and (4) back muscle actions. The model was validated using three different methods; precision was tested using correlation between predicted and measured results, accuracy using standard error between of predicted and measured results, and intuitive comparison of predicted results using sensitivity analyses.

• 한국지반공학회논문집
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• 제26권12호
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• pp.61-70
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• 2010

해안매립지와 같은 연약한 점토지반에 시공된 쇄석말뚝의 내진성능 평가를 위해 1g 진동대 실험을 수행하였다. 개량전 후 지반의 동적응답특성을 비교하기 위해 가속도 증폭 및 시간에 따른 전단변형, 전단파 속도 등을 평가하였다. 실험 결과, 쇄석말뚝으로 개량된 지반의 전단변형은 개량되지 않은 지반에 비해 감소되는 경향을 보이나, 단주기 지진파에는 더 높은 수준의 지반 가속도 증폭이 발생되는 것으로 나타났다. 따라서 쇄석말뚝으로 개량된 지반의 내진성능 향상여부는 모형실험과 함께 지반응답해석 등의 수행하여 평가되어야 한다고 판단된다.