• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.343-346
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• 2015

Ultra-thin body transistor is one of the emerging devices since it control leakage current flows through substrate. In addition, it can be operated by double gates, thus, its on/off current ratio is higher than conventional counterpart. In this paper, we design and investigate a CMOS inverter based on ultra-thin body MOSFETs to estimate its performance in real application. NEGF (non-equilibrium Green's function) method is used to obatain relationship between drain current and voltage. DC transfer is extracted from the relationship, and FO4 (fanout-of-4) propagation delay is reported as 5.1 ps estimated by a simple model.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1345-1348
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• 2002

그리드는 전세계적으로 분산되어 있는 다양한 고성능 장비뿐만 아니라 개인 PC까지 연결하여 가상의 단일 시스템을 구축하는 것을 의미한다. 그리드 환경에서 거대 문제(Grand Challenge Problem)을 해결하기 위해서는 그리드 기반 구조의 구축, 그리드 미들웨어의 개발, 그리드 어플리케이션과 포탈의 연구 및 개발이 이루어져야 한다. 본 논문에서는 이러한 특정 어플리케이션을 최적으로 지원할 수 있는 그리드 네트워크 구축을 위한 요구사항 명세와 이러한 정보들을 그리드 어플리케이션에 피드백으로 결합하여 그리드 환경에서 어플리케이션을 효과적으로 운영, 관리할 수 있는 시스템을 설계한다.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.229.1-229.1
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• 2003

Recently, the barrier membranes have been applied for regenerating bone surrounding peri-implant defects in guided bone regeneration(GBR). GBR membrane should provide mechanical support sufficient to withstand in vivo forces and maintain wound space for bone regeneration. The ability to exclude unwanted tissues of cells(connective tissue and epithelium) is needed. In addition large surface area is conductive to tissue ingrowth. The search for ideal materials that biocompatible, bioresorbable and can support the growth and phenotypic expression of osteoblasts is a major challenge in the biomedical application for the repair of bone defects. (omitted)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.82-86
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• 2004

To cope with the challenge from global market characterized by frequent changes in requirements, manufacturing enterprise should be able to promptly adjust its manufacturing system accordingly. Therefore, it is important to provide manufacturing system designer with an appropriate methodology to (re-)design a manufacturing system subject to requirements change. Axiomatic design theory focuses design activity mainly on functional consideration rather than physical, and has been known as effective especially in the conceptual design phase. This paper introduces an approach to apply the axiomatic design principle to manufacturing system design. It is shown that a new design solution can be reached quickly by finding design parameters for the added or revised functional requirements and thus achieving a set of functional requirements as well as design parameters that satisfy the independence axiom. Some illustrative examples are also given.

• Environmental Engineering Research
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• v.16 no.4
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• pp.227-230
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• 2011

Seawater desalination technology is a complicated and expensive process. Besides salt removal from seawater, thesignificant problem that needs to be solved is boron removal. Boron removal is difficult so it is a considerable challenge for the desalination process. The main technology of this process is reverse osmosis (RO). RO can remove salt and boron more effectively than other technologies. In a conventional seawater desalination process, coagulant is utilized for pre-treatment but it is difficult to remove boron through this stage. In this study, a coagulant called Mineral Cluster was examined for boron removal. Therefore, Mineral Cluster can be considered a potential coagulant for boron removal in seawater desalination technology.

• Korean Journal of Computational Design and Engineering
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• v.15 no.5
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• pp.343-353
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• 2010

Time to market and cost-efficient production are some of the challenge that manufacturing industries face. Modern methods of engineering can't help such organizations attain competitive advantage. To help these situations, MEMPHIS (Middleware for Exchanging Machinery and Product Data in Highly Immersive Systems) was introduced as an approach that enables VE (Virtual Engineering) and links engineering applications with VR (Virtual Reality) solutions. Thus an environment is provided to implement virtual design reviews and enable the application of virtual prototyping methods. However MEMPHIS could just handle Product data for virtual design review and simulation. In this paper, we newly define and develop the extended MEMPHIS that enables virtual manufacturing with Process, Resource and Plant data as well as Product data.

• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1199-1215
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• 2011

Relaxing an unrealistic assumption of a representative percolation model, this paper demonstrates that herd behavior leads to a high increase in volatility but not trading volume, in contrast with information flows that give rise to increases in both volatility and trading volume. Although detecting herd behavior has posed a great challenge due to its empirical difficulty, this paper proposes a new methodology for detecting trading days with herding. Furthermore, this paper suggests a herd-behavior-stochastic-volatility model, which accounts for herding in financial markets. Strong evidence in favor of the model specification over the standard stochastic volatility model is based on empirical application with high frequency data in the Korean equity market, strongly supporting the intuition that herd behavior causes excess volatility. In addition, this research indicates that strong persistence in volatility, which is a prevalent feature in financial markets, is likely attributed to herd behavior rather than news.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.155-158
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• 2024

Multipath, a major error source in urban GNSS positioning (global navigation satellite system), pose a challenge due to its site-dependent nature, varying with the user's signal reception environment. In our previous study, we introduced a technique generating GNSS multipath map in urban canyon. However, due to uncertainty in initial GNSS positions, applying multipath maps required generating multiple candidate positions. In this study, we present an efficient method for applying multipath maps by projecting the multipath correction in position domain. This approach effectively applies multipath maps, addressing the challenges posed by urban user position uncertainties.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.223-224
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• 2000

As technology level of TFT-LCD advances, application to TV becomes an emerging important area for LCD makers. In this paper, we review current LCD technology level to be used in TV such as liquid crystal response behavior, color accuracy, contrast ratio, brightness and panel size. Based on the understanding of current limitations in LCD compared with CRT, the improvement plan to render 'near perfect motion picture' reproduction with LCD is proposed. Digital TV is a great opportunity for digital LCD panels, but we have to solve remaining technical and cost issue in order to be competitive with other large size TV technologies such as PDP, CRT or projection type. In preparing the upcoming digital TV era with advanced TFT-LCD, the hurdles and prospect of larger size LCD-TV panels will be discussed.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.343-348
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• 2013

초임계 익형은 천음속 영역에서 비행하는 상업용 민간 항공기와 전투기 날개의 공력성능을 향상시키기 위해 Whitcomb R. T.가 제안 하였다. 초임계 익형은 상부표면을 평평하게 디자인하여 임계마하수보다 큰 마하수에서 나타나는 익형 주위의 충격파 출현을 지연시킴으로써 항력을 줄일 수 있고, 상부 표면의 평면 설계로 인한 양력 감소를 보정하기 위하여 하부 표면의 꼬리부분에 캠버가 있는 형상을 하고 있다. 본 연구에서는 EDISON CFD를 이용하여, 초임계 익형의 공력특성을 해석하고 Xfoil의 data와 비교 분석하였다. 또한, 초임계 익형의 형상을 변경하여 두께와 뒷전 캠버가 다른 초임계 익형을 설계하였다. 새로운 초임계 익형의 형상은 상용 프로그램 Maple12을 이용하여 Whitcomb Integral Supercritical Airfoil의 형상을 수정하여 구할 수 있다. 초임계 익형 주위의 유동을 2D압축성 유동으로 가정하고 EDISON CFD의 2D_Comp-2.0 솔버를 사용하여 수치해석을 수행하였다.