• Journal of Digital Convergence
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• v.12 no.12
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• pp.513-520
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• 2014

Since the beginning of history, men have done mimesis and produced illusion and succeeded art and culture instinctually. The subject which mention above included the object which can order and space around that. Perspective which began the Renaissance age was dominant way about understanding space in western history and it made modern visual system. Direction way of space which based perspective is changed as horizontal data included multi-layer structure in digital media age. This character make us possible to represent the space more efficiently. So we must have pay attention the direction way of space based on digital media, because it has meaning to show human value beyond a methodology of visual art culture.

• Journal of the Korean Geotechnical Society
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• v.16 no.2
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• pp.145-154
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• 2000

오늘날 폐기물 매립장의 구조적 안정성문제는 국내.외적으로 중요한 문제로 대두되고 있으며, 특히, 사면의 차수체계에서의 안정성에 대한 논란이 사회적 문제로 대두되고 있다. 또한, 우리 나라는 주민들의 NIMBY 현상과 국토의 효율적 활용을 위하여, 폐기물 매립장을 해안매립지나 산간지방에 많이 건설하고 있다. 그러나, 이러한 경우 사면구배가 급해지고 토목섬유의 활용이 불가피해져 안정성에 많은 문제점을 내포하게 된다. 이 연구는 폐기물 매립장 사면의 안정성을 해석하기 위하여, 원심모형실험을 실시하였다. 또한, 이론식 및 사면안정 해석 프로그램을 이용하여 안전을 산정하였다. 이 연구에 사용한 토목섬유 점토차수재(GCLs)의 팽윤도는 침출수와 증류수의 투과수에 대하여 22~25%의 팽윤도를 보였으며, 투수계수는 투과수가 침출수일 경우, 1.47$\times$10-10cm/sec, 증류수일 경우, 8.75$\times$10-11cm/sec의 값을 나타내었다. 원심모형실험 결과, 토목섬유 점토차수재의 포화여부와 지오멤브레인(HDPE)의 표면거칠기에 따라 사면 안전율이 각각 변화함을 알 수 있었으며, 표면이 거친 지오멤브레인과 건조한 토목섬유 점토차수재를 사용하였을 때, 파괴가 발생되지 않아 사면안정성이 높은 것으로 평가되었다. 또한, 이론에 의해 도출된 사면의 안전율과 사면안정 해석프로그램에 의한 안전율 계산 시, 전자의 경우가 후자의 경우보다 작게 평가됨을 알 수 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.11
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• pp.1005-1012
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• 2011

In this paper, the effect of wrinkling on the failure behavior of thin membrane was studied using geometrically nonlinear shell element post-buckling analysis with global-local analysis strategy. In the analysis, double-edge notched and single-edge notched tensile specimen configurations were considered. The analyses were performed for both cases with allowing and suppressing the wrinkling deformation. The results were investigated focusing on the effect of wrinkle development on the variation of J-integral values at the cut tip. The effect of cut lengths and the specimen lengths were also systematically studied.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.3
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• pp.195-203
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• 2015

In this paper, the dynamic behavior of wrinkled triangular solar sail was studied by finite element analysis. The analysis was proceeded first by performing static wrinkle analysis under tensile corner load on sail membrane, and then performing modal analysis. The membrane element method with wrinkle algorithm and the shell element post-buckling analysis method were used to account for the wrinkle deformation and the results were compared for analysis methods throughly. The comparison was also made to that without wrinkle consideration to investigate the effect of wrinkle deformation on the results. Cases with various loading cable angles were analyzed and the results were systematically examined.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1335-1342
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• 1988

In this paper, mechanical properties of mild steel plate which was pretreated by prestress and prestrain loading conditions were studied. The variation of the mechanical properties of the test materials is evaluated in the light of Taylor's work hardening theory. Through this experimental study, it is recognized that material showed unstable phenomena after cyclic loading and it will recover its stability after a certain period of time accompaning the increment of hardness and the yield strength of the material. Also, the strength of smooth specimen, the notch strength of notch specimen and propagation behavior of fatigue specimen which were subjected to prestress and prestrain reveal that the optimal conditions may occur in the first, the middle and the later half of stage II of Taylor's work hardening theory, respectively.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1473-1476
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• 2003

웹의 성장으로 사용자는 언제 어디서든지 유용한 정보의 이용이 가능해졌다. 웹이 광범위하게 사용됨에 따라 정보를 획득하기 위해 대다수의 사용자들이 웹을 의존하고 있다. 그러나 웹상의 모든 정보는 정보가 저장되어 있는 서버의 관리자들에 의해 계속적으로 갱신 또는 삭제되어 가고 있어 기존의 정보들은 그것의 중요성 여부와 관계없이 대다수의 정보가 소멸되고 있다. 따라서 오랜 기간에 거쳐 생성된 웹상의 중요 데이터(importance data)들을 효율적으로 활용하기 위한 웹 아카이브(archive) 시스템이 연구되었다. 그러나 현재 존재하는 웹 아카이브 시스템은 갱신되기 이전의 데이터를 다루기 위한 체계적인 처리기법을 제시하지 못하고, 수집된 데이터들에 대한 연관관계를 저장하지 못하여 데이터 관리에 있어 비효율적이라는 문제점을 가지고 있다. 이에 따라 본 논문에서는 웹으로부터 다운로드한 데이터를 레포지토리(repository)에 효율적으로 저장하기 위해 설계된 대표적인 WebBase를 기반으로 하여 갱신되기 이전의 모든 정보들에 대한 내용을 히스토리(history) 저장소내에 저장하여 정보를 효율적으로 활용할 수 있는 웹 아카이브 시스템의 구조를 제안한다.

• Spatial Information Research
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• v.5 no.2
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• pp.147-160
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• 1997

"The "Map Algebra", beeing recognized as a viable theoretical framework for GIS (Geographica Infonnation System), models map layers as "operands" which are the basic unit of geo-processing, and a variety of GIS commands as "operators." In this paper, we attempt at lifting some limitations of map algebras proposed in GIS literature. First, we model map layer as "function" such that we may employ the notion of meta operator (or, higher-order funtion) available in the functional programming paradigm. This approach provides map algebraic language with "programmability" needed in GIS user language. Second, we extend the semantics of, and improve on the sytactic structure of map algebraic language. Mer the data model and language associated with map algebra are formalized, we proceed to design and implement a prototype of map algebraic processor. The parser of the language in our prototype plays the role of transforming the native and heterogeneous user language of current GISs into a canonical map algebraic language. The prototype, named "MapSee" is a proof-of-concept system for the ideas we propsed in this paper. We believe that the uniform interface based on the map algebraic language will make promising infrastructure to support "Internet GIS." This is because the uniform but powerful interface through the Web clients allow access to both geo-data and geo-processing resources distributed over the network.to both geo-data and geo-processing resources distributed over the network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.87-94
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• 2023

As the latest weapon systems and electronic equipments are increasingly demanding stealth technology to improve the survivability of allies, it is necessary to implement low-observability technology that reduces the radar cross section(RCS). In order to implement this stealth technology, a method for low RCS characteristics by applying a shape design or a electromagnetic wave absorber is widely used. However, active phased array antennas have structural limitations in shape design, also when a absorber is applied to it, the performance of the antenna is degraded. Therefore, in this paper, in order to realize the low RCS characteristics of the active phased array antenna operating in the X-band, individual radiating elements suitable for applying the radio wave absorber were selected, and a 13x13 array antenna was designed and manufactured. Next, by comparing the measured results of the relative RCS and electrical performance for the manufactured antenna according to the presence and type of the absorber, it is shown that the electrical performance is maintained at an equal or higher level while obtaining the low RCS characteristics. Thereby the method proposed in this paper for implementing the low RCS characteristics was validated. Finally, it was confirmed that when the wave absorber is applied to the array antenna, the limitation of its performance deterioration can be overcome.

• The Journal of Bigdata
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• v.7 no.1
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• pp.213-224
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• 2022

In logistics and distribution, Market Basket Analysis (MBA) is used as an important means to analyze the correlation between major sales products and to increase internal operational efficiency. In particular, the results of market basket analysis are used as important reference data for decision-making processes such as product purchase prediction, product recommendation, and product display structure in stores. With the recent development of e-commerce, the number of items handled by a single distribution and logistics company has rapidly increased, And the existing analytical methods such as Apriori and FP-Growth have slowed down due to the exponential increase in the amount of calculation and applied to actual business. There is a limit to examining important association rules to overcome this limitation, In this study, at the Main-Category level, which is the highest classification system of products, the utility item set mining technique that can consider the sales volume of products together was used to first select a group of products mainly sold together. Then, at the sub-category level, the types of products sold together were identified using FP-Growth. By using this sequential layer filtering technique, it may be possible to reduce the unnecessary calculations and to find practically usable rules for enhancing the effectiveness and profitability.

• Membrane Journal
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• v.10 no.1
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• pp.47-53
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• 2000

The artificial lung is a device used to replace the function of the lungs. The major function of the lung is to remove carbon dioxide from the venous blood and replace it with oxygen, or arterialize the blood. And the function of the artificial lung is to provide an adequate amount of oxygenated blood to all the tissues of body during the open heart surgery. Extracorporeal life support(ECLS or ECMO) is standard treatment for severe respiratory failure but poses many contributions to future lung transplantation. Artificial Lung or membrane oxygenators available today, based on microporous polypropylene fibers, are associated with two major problems. They require systemic anticoagulation of the patient and they allow serum leakage across the membrane from the blood side to the gas side during long-term use. We obtained newly fabricated polypropylene(PP)/polydimethylsiloxane(PDMS) membranes which combined PP membrane, a microporous support layer with PDMS, and we had investiaged a technique for minimizing serum lekage of polypropylene(PP) membrane. The gas permeability of each PP/PDMS membrane was almost constant before and after the whole blood test by Lee-White method, while that of PP membrane was significantly reduced. Therefore the PP/PDMS membrane could be prevented serum leakage of PP membrane. In addition, the gas permeability of $CO_2$ in PP/PDMS membrane was 11.5 times higher as compared with that of $O_2$.