• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.833-836
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• 2001

The thermomechanical behaviors of the shape memory alloy were conducted through the finite element analysis of ABAQUS with UMAT user subroutine. The unified thermomechanical constitutive equation suggested by Lagoudas was adapted into the UMAT user subroutine to investigate the characteristics of the shape memory alloy. The three cases were solved to investigate the thermomechanical characteristics of the shape memory alloy. The material properties for the analysis were obtained by DSC and DMA techniques. According to the results, the thermomechanical characteristics, such as a shape memory effect and a pseudoelastic effect, could be obtained through the finite element analysis and the analysis results were revealed to agree well with the experimental results. Therefore, the finite element analysis using UMAT user subroutine is one of prominent analysis techniques to investigate the thermomechnical behaviors of the shape memory alloy quantitatively.

• Structural Engineering and Mechanics
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• 제48권1호
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• pp.41-56
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• 2013

Initiation and growth of delamination is a great concern of designers of composite structures. Interface elements with de-cohesive constitutive law in the content of continuum damage mechanics can be used to predict initiation and growth of delamination in single and mixed mode conditions. In this paper, an interface element based on the cohesive zone method has been developed to simulate delaminatoin growth of post-buckled laminate under fatigue loading. The model was programmed as the user element and user material by the "User Programmable Features" in ANSYS finite element software. The interface element is a three-dimensional 20 node brick with small thickness. Because of mixed-mode condition of stress field at the delamination-front of post-buckled laminates, a mixed-mode bilinear constitutive law has been used as user material in this model. The constitutive law of interface element has been verified by modelling of a single element. A composite laminate with initial delamination under quasi-static compressive Loading available from literature has been remodeled with the present approach. Moreover, it will be shown that, the closer the delamination to the free surface of laminate, the slower the delamination growth under compressive fatigue loading. The effects of laminate configuration on delamination growth are also investigated.

• Computers and Concrete
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• 제16권2호
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• pp.287-309
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• 2015

FormWorks-Plus is a generalized public domain user-friendly preprocessor developed to facilitate the process of creating finite element models for structural analysis programs. The lack of a graphical user interface in most academic analysis programs forces users to input the structural model information into the standard text files, which is a time-consuming and error-prone process. FormWorks-Plus enables engineers to conveniently set up the finite element model in a graphical environment, eliminating the problems associated with conventional input text files and improving the user's perception of the application. In this paper, a brief overview of the FormWorks-Plus structure is presented, followed by a detailed explanation of the main features of the program. In addition, demonstration is made of the application of FormWorks-Plus in combination with VecTor programs, advanced nonlinear analysis tools for reinforced concrete structures. Finally, aspects relating to the modelling and analysis of three case studies are discussed: a reinforced concrete beam-column joint, a steel-concrete composite shear wall, and a SFRC shear panel. The unique mixed-type frame-membrane modelling procedure implemented in FormWorks-Plus can address the limitations associated with most frame type analyses.

• 한국정보통신학회논문지
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• 제16권6호
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• pp.1113-1118
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• 2012

국제해사기구의 e-navigation은 선박 안전 운항을 위한 사용자 지향형 서비스 제공의 한 전략으로 인적요소평가를 적용하여 인간공학적 측면의 해결 대안 평가를 수행해야한다. 기존 국제해사기구의 인적요소평가 권고 지침은 규정 개발자의 입장에서 인적요소를 제시하고 있어 e-navigation에 요구되는 사용자 지향형 평가를 위한 새로운 인적요소 개발이 필요하다. 본 논문에서는 국제해사기구의 기존 인적요소평가절차의 의미와 경과를 분석하고 사용자 지향적 새로운 전략인 e-navigation의 취지에 부합하는 새로운 인적요소평가절차를 위해 사용자 지향형 인적요소평가를 위한 인적요소 검토항목과 사용자 외부요인에 의한 위협요소 및 내부요인에 의한 인적 오류 요소를 개발하여 이를 반영한 e-navigation 인적요소평가절차를 도출하였다.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2001년도 춘계학술발표대회 논문집
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• pp.121-127
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• 2001

An unified measure of user interface efficiency and aesthetics for cyber museum is proposed. First, general structure of cyber museum is discussed and hierarchical analyses are done for sample sites. Usability tests based on the hierarchical analyses yield statistics of user access frequency and persistency for each page, on which access probability is deduced. Second, visual occupancy, a measure of efficiency of user interface element based on access probability is defined. The hierarchical statistics of visual occupancy can be an index for characterization and classification of cyber museums. Examples are provided.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.654-659
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• 2003

PVAP (Pressure Vessel Analysis Program V1.0) was developed by adopting the finite element analysis program ANSYS V6.0, and Microsoft Visual Basic V6.0 was also utilized for the interfacing and handling of input and output data during the analysis. PVAP offers the end user the ability to design and analyze vessels in strict accordance with ASME Section VIII, Division 2. More importantly, the user is not required to make any design decisions during the input of the vessel. PVAP consists of three analysis modules for the finite element analysis of the primary components of pressure vessel such as head, shell, nozzle, and skirt. In each module, finite element analysis can be performed automatically only if the end user gives the dimension of the vessel. Furthermore, the calculated results are compared and evaluated in accordance with the criteria given in ASME Boiler and Pressure Vessel Code, Section VIII, Division 2. In particular, heat transfer analysis and consecutive thermal stress analysis for the junction between skirt and head can be carried out automatically in the skirt-tohead module. Finally, report including the above results is created automatically in Microsoft Word format.

• 전산구조공학
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• 제28권4호
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• pp.7-11
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• 2015

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1997년도 추계학술대회논문집
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• pp.372-375
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• 1997

Classivication scheme of usability element for the evaluation of consumer electronic product was developed in this study. Using hierachical structuring and clustering methods, usability element of consumer products interface is developed both for the performance perspective and for the image/appeal perspective of a product. Perfoormance element included variables such as simplicity, directness, learn- ability, flexibility, user support and effectiveness. Image/Appeal element included variables such as sensibility, descriptive impression, evaluation of appeal, and attitude towards the product. The classifi- cation scheme developed in this study is found to be comprehensive and robust relative to other existing paradigms. They can be effectively used and applied for the usability evaluation of consumer electronic products.

• 한국해양공학회지
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• 제28권1호
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• pp.34-46
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• 2014

This paper discusses a new formulation for the failure strain in the average stress triaxiaility domain for a low-temperature high-strength steel (EH36). The new formula available at a low average stress triaxiality zone is proposed based on the comparison of two results from tensile tests of flat type specimens and their numerical simulations. In order to confirm the validity of the failure strain formulation, a user-subroutine was developed using Abaqus/Explicit, which is known to be one of the most popular commercial finite element analysis codes. Numerical fracture simulations with the user-subroutine were conducted for all the tensile tests. A comparison of the engineering stress-strain curves and engineering failure strain obtained from the numerical simulation with the user-subroutine for the tensile tests revealed that the newly developed user-subroutine effectively predicts the initiation of failure.

• 인터넷정보학회논문지
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• 제7권1호
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• pp.59-64
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• 2006

GKRS(Global Key Recovery System)는 키복구 기관과 공개키 인증기관(CA)의 기능들을 결합한 시스템이다[1]. GKRS의 다른 특징으로 User-Dominance(즉, 사용자가 자신의 공개-비밀키 쌍과 특히 공개-비밀키 쌍의 유용성을 검증하기 위한 공개 인자(public element)를 선택하도록 한다.)가 GKRS의 광범위한 적용을 위한 아주 중요한 요소로서 제안되었다. 본 논문에서는 CA에 의해 채택된 User-Dominance 방식과 그에 해당하는 키 검증 방식이 CA에 대한 사용자들의 기만 공격을 허용함을 보임으로서 GKRS의 RSA 방식을 공격하고, 이와 같은 공격으로부터 안전한 개선된 GKRS 방식을 제안한다. 제안된 방식은 CA가 랜덤 수를 이용하여 사용자의 기만 공격 확률을 무시할 정도로 작게 함으로서 안전성을 확보하고 있다.