• International Journal of Naval Architecture and Ocean Engineering
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• 제7권3호
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• pp.466-477
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• 2015

In this study, a numerical prediction method on manoeuvrability of Wind Turbine Installation Vessel (WTIV) is presented. Planar Motion Mechanism (PMM) captive test for the bare hull of WTIV is carried out in the model basin and compared with the numerical results using RANS simulation based on Open-source Field Operation And Manipulation (OpenFOAM) calculation to validate the developed method. The manoeuvrability of WTIV with skeg and/or without skeg is investigated using the numerical approach along with the captive model test. In the numerical calculations, the dynamic stability index which indicates the course keeping ability is evaluated and compared for three different hull configurations i.e. bare hull and other two hulls with center skeg and twin skeg. This paper proves that the numerical approach using RANS simulation can be readily applied to estimate the manoeuvrability of WTIV at the initial design stage.

• 방송공학회논문지
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• 제28권1호
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• pp.149-152
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• 2023

본 논문에서는 소프트웨어 정의 라디오 (SDR: Software-defined Radio)를 활용하여 실시간 동영상 송수신기를 구현하기 위한 접근 방법을 제시한다. 이를 통해 최근 주목받고 있는 개방형 무선 접속망(O-RAN: Open Radio Access Network)을 연구하고 이를 SDR 장치와 개방형 소프트웨어를 통해 구현하고자 하는 연구자들의 접근 문턱을 낮추고 새로운 시각과 통찰력을 제공할 수 있을 것으로 기대한다.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.197-204
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• 2020

Nowadays, many construction engineering and technology enterprises are evolving to find that prosperity is driven and inspired by an open economy with dynamic markets and fierce multifaceted competition. Besides brand and product uniqueness, the ability to quickly provide customers with quotes are matters of concern. Such a requirement for prompt cost estimation of construction investment projects with the use of a construction price index poses a significant challenge to contractors. This is because the nature of the construction industry is shaped by changes in domestic and foreign economic factors, socio-financial issues, and is under the influence of various micro and macro factors. This paper presents a fuzzy decision-making approach for calculating critical factors that affect the construction price index. A qualitative approach was implemented based on in-depth interviews of experts in the construction industry in Vietnam. A synthetic comparison matrix was calculated using Buckley approach. The CoA approach was applied to defuzzified the fuzzy weights of factors that affect the construction price index. The research results show that the top five critical factors affecting the construction price index in Vietnam are (1) consumer price index, (2) gross domestic product, (3) basic interest rate, (4) foreign exchange rate, and (5) total export and import.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.422-425
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• 1997

Computer Integrated Manufacturing (CIM) is undoubtedly one of the most influential concepts to have been introduced into the manufacturing world in recent times. The successful CIM application is greatly depended on the way of the approach to given manufacturing environments. This paper reports a new approach in building CIM systems trough the development of a poen cell controller.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1993-1998
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• 2004

This paper proposes a new framework for control system design, called the data-based control approach or data space approach, in which the input and output data of a dynamical system is directly and solely used to analyze or design a control system without the employment of any mathematical models like transfer functions, state space equations, and kernel representations. Since, in this approach, most of the analysis and design processes are carried out in the domain of the data space, we introduce some notions of geometrical objects, e.g., the openloop and closed-loop data spaces, which serve as the system representations in the data space. In addition, we establish a relationship between the open-loop and closed-loop data spaces that the closed-loop data space is contained in the open-loop data space as one of its subspaces. By using this relationship, we can derive the data-based stabilization condition for a linear time-invariant discrete-time system, which leads to a linear matrix inequality with a rank constraint.

• Asia pacific journal of information systems
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• 제29권4호
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• pp.690-716
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• 2019

Open innovation has attracted significant attention from both academics and practitioners. However, theoretical and empirical researchers disagree on how open innovation improves firm performance. The inconsistent results reported in the literature may be attributed to the fact that they failed to provide an integrative view of how to make use of internal and external knowledge to enhance innovation performance. Furthermore, although the adoption value of innovation approaches varies depending on firm size and IT capabilities, their impacts have not been adequately taken into consideration. Drawing on complementarity theory, this study revisits the research problem and develops eight hypotheses. Surveys collected from 339 Korean firms were analyzed to test the hypotheses using the supermodularity functions. The results indicated that an internal knowledge-oriented innovation approach has a positive impact on innovation performance regardless of firm size. However, an external knowledge-oriented innovation approach has a positive effect on innovation performance in large firms while having no significant effect on innovation performance of SMEs. Results also confirmed a complementary relationship between internal and external knowledge-oriented innovation approaches in large firms, whereas substitutable relationships were confirmed in SMEs. This study sheds new light on open innovation by identifying the role of different types of innovation approaches, firm size, and IT capabilities.

• 한국실내디자인학회논문집
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• 제15권5호
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• pp.157-166
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• 2006

Recently, it appears several counterproposals about desirable figures of urban architecture. All of them proposes 'publicity' with cohernt tendency. The reason why it concentrates quantitative expansion of city without united design by urban plannar is that neglect quality values of city. As a solution of poor environment, there cue out the various efforts, about problem of each building, problem of city space, problem of laws and so forth. The reason why necessity of public space was embossed in that architecture extend the activity of citizen and make up the city space. But, each building pursues the private interest, so it is difficult to secure a public space with a high hand. Thus, architecture law has been revised in 1991 and bring the system of open space to match up the publicity and the private interest. Actually, western country brought it and obtained excellent results. While quantity of open space have increased since 1991, a lot of problems revealed in real usage and quality. By means of problem's solution, this study focus on the diversion of recognition for necessity of various open space. In result, on the occasion of approach and openess, except for several building, most glass a facade and the pedestrian can approach easily. Moreover, office buildings near the subway station connected with their low floor. So, the office buildings give openess to pedestrian and a people can approach easily to the buildings. On the occasion of amenity, most have bank and lobby on the first floor and have facilities on the underground floor. It leave open. But the reason why they have bank and lobby is that the space is dry and boring(without elements of nature and rest space). Hence, to make a space full of vitality, it have to plan various design elements and facilities. First of all, plan of indoor public space have to make up facility for the public interest. This study is basic investigation for necessity of indoor public space and through the survey of office buildings, it analyze the character of plan and find out the method of publicity's realization.

• Ocean Systems Engineering
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• 제8권4호
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• pp.381-407
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• 2018

This paper presents a hybrid numerical approach, which combines a two-phase Navier-Stokes model (NS) and the fully nonlinear potential theory (FNPT), for modelling wave-structure interaction. The former governs the computational domain near the structure, where the viscous and turbulent effects are significant, and is solved by OpenFOAM/InterDyMFoam which utilising the finite volume method (FVM) with a Volume of Fluid (VOF) for the phase identification. The latter covers the rest of the domain, where the fluid may be considered as incompressible, inviscid and irrotational, and solved by using the Quasi Arbitrary Lagrangian-Eulerian finite element method (QALE-FEM). These two models are weakly coupled using a zonal (spatially hierarchical) approach. Considering the inconsistence of the solutions at the boundaries between two different sub-domains governed by two fundamentally different models, a relaxation (transitional) zone is introduced, where the velocity, pressure and surface elevations are taken as the weighted summation of the solutions by two models. In order to tackle the challenges associated and maximise the computational efficiency, further developments of the QALE-FEM have been made. These include the derivation of an arbitrary Lagrangian-Eulerian FNPT and application of a robust gradient calculation scheme for estimating the velocity. The present hybrid model is applied to the numerical simulation of a fixed horizontal cylinder subjected to a unidirectional wave with or without following current. The convergence property, the optimisation of the relaxation zone, the accuracy and the computational efficiency are discussed. Although the idea of the weakly coupling using the zonal approach is not new, the present hybrid model is the first one to couple the QALE-FEM with OpenFOAM solver and/or to be applied to numerical simulate the wave-structure interaction with presence of current.

• 대한수학교육학회지:수학교육학연구
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• 제8권2호
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• pp.405-423
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• 1998

This study aims to reflect the origin and the meaning of open education and to derive pedagogical principles for open mathematics education. Open education originates from Socrates who was the founder of discovery learning and has been developed by Locke, Rousseau, Froebel, Montessori, Dewey, Piaget, and so on. Thus open education is based on Humanism and Piaget's psychology. The aim of open education consists in developing potentials of children. The characteristics of open education can be summarized as follows: open curriculum, individualized instruction, diverse group organization and various instruction models, rich educational environment, and cooperative interaction based on open human relations. After considering the aims and the characteristics of open education, this study tries to suggest the aims and the directions for open mathematics education according to the philosophy of open education. The aim of open mathematics education is to develop mathematical potentials of children and to foster their mathematical appreciative view. In order to realize the aim, this study suggests five pedagogical principles. Firstly, the mathematical knowledge of children should be integrated by structurizing. Secondly, exploration activities for all kinds of real and concrete situations should be starting points of mathematics learning for the children. Thirdly, open-ended problem approach can facilitate children's diverse ways of thinking. Fourthly, the mathematics educators should emphasize the social interaction through small-group cooperation. Finally, rich educational environment should be provided by offering concrete and diverse material. In order to make open mathematics education effective, some considerations are required in terms of open mathematics curriculum, integrated construction of textbooks, autonomy of teachers and inquiry into children's mathematical capability.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2004년도 추계학술대회 논문집
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• pp.295-300
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• 2004

Growing concern and technical improvement in the housing industry has promoted continuous customization to be the most significant parameter for ecological and social sustainability of housing. The basic principle of Open Building is based on the concept of sustainability, but the theoretical relationship of the open housing system in terms of environmental architecture has not been examined profoundly yet. In order to generate an overall approach toward sustainable housing, a further alignment between Open Building and sustainability should be established. Therefore, this study aims at the establishment of the theoretical relationship between Open Housing system and environmental architecture, and the examination of Open Housing system in terms of sustainability for the suggestion of the future development in housing environment.