• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.904-921
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• 2014

The main objective of this paper is to propose a new Finite Element (FE) model updating technique for damped beam structures. The present method consists of a FE model updating, a Degree of Freedom (DOF) reduction method and a damping matrix identification method. In order to accomplish the goal of this study, first, a sensitivity-based FE model updating method using the natural frequencies and the zero frequencies is introduced. Second, an Iterated Improved Reduced System (IIRS) technique is employed to reduce the number of DOF of FE model. Third, a damping matrix is estimated using modal damping ratios identified by a curve-fitting method and modified matrices which are obtained through the model updating and the DOF reduction. The proposed FE model updating method is verified using a real cantilever beam attached damping material on one side. The updated result shows that the proposed method can lead to accurate model updating of damped structures.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.980-992
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• 2019

This paper describes a model test and numerical simulation of a 750-kW-semi-submersible platform wind turbine under several wind and wave conditions for validation of the numerical simulation model. The semi-submersible platform was designed to support the 750-kW-wind turbine class and operate at a water depth of 50 m. The model tests were performed to estimate the performance characteristics of the wind turbine system in the wide tank of the University of Ulsan. Motions and loads of the wind turbine system under the wind and wave conditions were measured and analyzed. The NREL-FAST code was used to simulate the wind turbine system, and the results were compared with those of the test model. The results demonstrate that the numerical simulation captures noticeably the fully coupled floating wind turbine dynamic responses. Also, the model shows a good stability and small responses during waves, wind, and operation of the 750-kW-floating offshore wind turbine.

• Information Systems Review
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• v.12 no.2
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• pp.1-23
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• 2010

Most enterprise information systems today are silo systems in that they are not properly aligned nor integrated with one another. Such silo systems result because enterprises lack an architectural perspective in the planning and development of the systems. This paper proposes an Enterprise Architecture Orientation Model as a framework for the analysis, planning and design of the architectural quality of enterprise information systems. The model decomposes enterprise architecture into two dimensions-alignment and integration, and specifies for each dimension the general development and evolution stages enterprises may traverse. The alignment dimension represents the vertical strategic alignment of the systems with the vision, mission, strategy and goals of the enterprise, and is analyzed in terms of the performance, capability, and strategy of the enterprise. The integration dimension, on the other hand, represents the horizontal and functional integration among the systems that span organizational functions and boundaries, and is analyzed in terms of such technological components as IT infrastructure, data, application, and business processes. The model combines the alignment and integration dimensions to form a two-dimensional conceptual space for mapping the architectural quality of the enterprise. It is proposed that an enterprise use the model to identify and understand its position now and in the future in the architectural quality of the enterprise information systems. It is also proposed that the model provides a tool for the planning and design of the transition from one stage to the next in the alignment and integration of the systems to reach an architectural maturity. At the end, the paper discusses how the model can be applied differently according to the strategic orientation of the enterprise. An example of the usage of the model is presented.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.82-93
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• 2019

In this paper, the ductile fracture criteria for a marine structural steel (EH36) are presented and validated. The theoretical background of the recently developed Hosford-Coulomb (HC) fracture strain model and the DSSE fracture strain model which was developed to apply to the shell elements is described. In order to accurately estimate the flow stress in the large strain range up to the fracture, the material constants for the combined Swift-Voce constitutive equation were derived by the numerical analyses of the smooth and notched specimens made from the EH36 steel. As a result of applying the Swift-Voce flow stress to the other notched specimen model, a very accurate load - displacement curve could be derived. The material constants of the HC fracture strain and DSSE fracture strain models were independently calibrated based on the numerical analyses for the smooth and notch specimen tests. The user subroutine (VUMAT of Abaqus) was developed to verify the accuracy of the combined HC-DSSE fracture strain model. An asymmetric notch specimen was used as verification model. It was confirmed that the fracture of the asymmetric specimen can be accurately predicted when a very small solid elements are used together with the HC fracture strain model. On the other hand, the combined HC-DSSE fracture strain model can predict accurately the fracture of shell element model while the shell element size effect becomes less sensitive.

• Proceedings of the Korea Database Society Conference
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• 1999.06a
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• pp.487-495
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• 1999

본 논문은 Zachman ＆ Soho ［8］의 확장 정보 System 체계(extended lnformation System Architecture)의 개념을 ARIS Tool을 이용하여 구현한 Case study이다. 본 논문의 특징은 전략, Process, 조직,Data, Network, Time의 6 개 Model의 연계구조와 각 Model의 계층적 관계를 인도의 대표적 기업 중 하나인 TATA 제철소 냉연 공장의 신규 생산관리 System 구축사례를 통하여 제시하였다는데 있다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 1999.03a
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• pp.487-495
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• 1999

본 논문은 Zachman & Soho [8]의 확장 정보 System 체계(extended information System Architecture)의 개념을 ARIS Tool을 이용하여 구현한 Case Study 이다. 본 논문의 특징은 전략, Process, 조직, Data, Network, Time의 6개 Model의 연계구조와 각 Model의 계층적 관계를 인도의 대표적 기업 중 하나인 TATA 제철소 냉연 공장의 신규 생산과리 System 구축사례를 통하여 제시하였는데 있다.

• Journal of the Korea society of information convergence
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• v.1 no.1
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• pp.41-46
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• 2008

Contents application from contents development of web technical base and with the operation different environment information of the educational resources integration the importance and necessity of the management central chain e-Learning system will be able to operate are raising its head with base. Is the actual condition which develops the development process where but, the education application currently is not standardized in base. Approaches with an educational domain from the present paper consequently, and defines MDA(Model Driven Architecture) coats e-Learning System. Also uses a studying contents standard metadata and about the contents storage space analyzes and plans the core property which uses MDA automatic tools leads and under developing boil e-Learning System will be able to provide the contents which does in actual professor own necessity.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.2
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• pp.120-128
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• 2013

This paper presents the results of sloshing experiments having different fluids in model tanks with various density ratios. The experimental model consisting water and air at ambient, which has been commonly used, is not consistent in density ratio with that of an actual LNG cargo tank. Therefore, an advanced experimental scheme is developed to consider the same density ratio of LNG and NG by using a mixed gas of sulfur hexafluoride ($SF_6$) and nitrogen ($N_2$). For experimental observation, a two-dimensional model tank of 1/40 scale and a three-dimensional model tank of 1/50 scale have been manufactured and tested at various conditions. Two different fillings with various excitation frequencies under regular motions have been considered for the two-dimensional model tank, and three different filling levels under irregular motions have been imposed for the three-dimensional model tank. The density ratio between gas and liquid varies from the ratio of the ambient air and water to that of the actual LNG cargo container, and the different composition of gas is used for this variation. Based on the present experimental results, it is found that the decrease of sloshing pressure is predicted when the density ratio increases.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.247-252
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• 2008

Systems architecture of information models for construction industry is introduced. The architecture ful fills international standards, such as ISO 10303(STEP) and IAI IFC, etc. It is defined in web service description language(WSDL) and ISO 10303-11(EXPRESS) language. A standard platform for this standard architecture is also developed. This platform has several tools which can transform EXPRESS description file into C++ or Java languages and which also can generate an IDL file or OWL file from an EXPRESS file. System architects, software engineers, information system consultants can use these standards to define their information model for construction industry in standardized way. Construction engineers can test this information model with ease using standard testing tools and testing method, which is also a part of standard architecture of information systems for virtual construction.

• Computers and Concrete
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• v.17 no.5
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• pp.655-672
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• 2016

A predictive model for chloride binding isotherms of blended cements with various supplementary cementitious materials (SCMs) was established in this work. Totally 560 data points regarding the chloride binding isotherms of 106 various cements were collected from literature. The total amount of bound chloride for each mixture was expressed a combinational function of the predicted phase assemblage and binding isotherms of various hydrated phases. New quantitative expressions regarding the chloride binding isotherms of calcium-silicate-hydrate (C-S-H), AFm, and hydrotalcite phases were provided. New insights about the roles of SCMs on binding capabilities of ordinary portland cements (OPC) were discussed. The proposed model was verified using separate data from different sources and was shown to be reasonably accurate.