• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.385-394
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• 1999

제품을 설계하는 디자이너나 엔지니어는 많은 시간과 노력을 들이지 않고서 그들이 설계한 3차원 제품 모델에 대한 사실적인 이미지를 원한다. 디자인 프로세스의 초기인 개념 설계에서부터 설계검증, 그리고 가공 과정에서 사실적인 이미지가 매우 유용하므로, 대부분의 주요 CAD 제작사는 그들의 CAD 소프트웨어에 고급 렌더링 기능을 추가하고 있다. 상용의 CAD/CAM 모델러에서는 NURB 곡면을 기초로 모델링을 수행하므로, NURB 곡면을 렌더링할 수 있는 패키지가 필요하다. VIF(Visual InterFace) 렌더링 라이브러리는 A-buffer 방식과 Ray tracing 방식의 두 가지 고급 렌더링 모드를 제공한다. 다각형은 물론 NURB 곡면을 입력으로 받아 사용자가 설정한 표면의 각종 계수, 원하는 view와 설정된 광원에 따라 이미지를 만들고 다양한 형태로 출력시킬 수 있는 다양한 기능을 제공한다. 본 논문에서는 VIF 렌더링 라이브러리에 대한 구조와 기능별로 분류된 함수에 대하여 설명하며, 실제로 CAD/CAM 시스템과 통합되어 구상설계에서부터 3차원 설계 모델링에 이르기까지의 제조공정에서 설계검증 툴로써 어떻게 활용되고 있는가에 대하여 기술한다.Abstract Engineers and industrial designers want to produce a realistic-looking images of a 3D model without spending a lot of time and money. Photo-realistic images are so useful from the conceptual design, through its verification, to the machining, that most major CAD venders offer built-in as well as add-on photo-realistic rendering capability to their core CAD software. Since 3D model is consists of a set of NURB surfaces in commercial CAD packages, we need a renderer which handles NURB surface as well as other primitives.A new rendering library called VIF (Visual InterFace) provides two photo-realistic rendering modes: A-buffer and Ray tracing. As an input data it takes NURB surfaces as well as polygonal data and produces images in accordance with the surface parameters, view and lights set by user and outputs image with different formats. This paper describes the overall architecture of VIF and its library functions classified by their functionalities, and discusses how VIF is used as a graphical verification tool in manufacturing processes from the conceptual design to 3D modeling.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.4
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• pp.45-51
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• 2009

Different countries around the world, using their traditional culture as a background, are promoting new changes and reformation in development and publicity method of cultural contents to promote national interests and to increase their competitiveness. Also, as the citizen's standard of living and quality of living goes up, various demands for the enjoyment of traditional culture goes up accordingly as well. As the cultural assets environment become more complicated and diverse, there is a need for systematic management and preservation plan. Keeping these viewpoints in mind, the geo-spatial information provision service using the web provides various forms of services such as satellite imagery, terrain, and 3D viewing, enabling the user to gain concrete spatial information on specific areas. The geo-spatial information using 3D modeling is done only in limited spaces because of construction expenses or difficulties in management and maintenance. In this thesis, I would like to propose Effective method for the GoogleEarth Uploading through simplification of 3D object for the publicity of traditional buildings and Cultural Resources and Tourist Attractions.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.43-52
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• 2009

LIDAR data, as the source of the 3D information of buildings, are used many modeling fields such as three-dimensional city models in urban planning and the visibility analysis of buildings. This study suggests a methodology, that is characterized by combining image-based and point-based process, for minimizing the user's intervention and automatically extracting building boundary only using the LIDAR data. Image processing methodology is firstly used to separate building and non-building regions from LIDAR data. Moreover, building regions are then classified main roof into remaining parts by the statistical analysis of height values, and the remaining parts are processed separately. Through the experimental results of study areas which exist many types of buildings, for example, apartment-type, stair-type, complex-type, etc. Approximately 90% building boundaries are automatically extracted by the proposed methodology.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5301-5323
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• 2017

Small cell deployment offers a low-cost solution for the boosted traffic demand in heterogeneous cellular networks (HCNs). Besides improved spatial spectrum efficiency and energy efficiency, future HCNs are also featured with the trend of network architecture convergence and feasibility for flexible mobile applications. To achieve these goals, dual connectivity (DC) is playing a more and more important role to support control/user-plane splitting, which enables maintaining fixed control channel connections for reliability. In this paper, we develop a tractable framework for the downlink SINR analysis of DC assisted HCN. Based on stochastic geometry model, the data-control joint coverage probabilities under multi-frequency and single-frequency tiering are derived, which involve quick integrals and admit simple closed-forms in special cases. Monte Carlo simulations confirm the accuracy of the expressions. It is observed that the increase in mobility robustness of DC is at the price of control channel SINR degradation. This degradation severely worsens the joint coverage performance under single-frequency tiering, proving multi-frequency tiering a more feasible networking scheme to utilize the advantage of DC effectively. Moreover, the joint coverage probability can be maximized by adjusting the density ratio of small cell and macro cell eNBs under multi-frequency tiering, though changing cell association bias has little impact on the level of the maximal coverage performance.

• Journal of The Korean Digital Architecture Interior Association
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• v.12 no.4
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• pp.13-20
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• 2012

The recent advances in digital technology allow the use of BIM for integratively managing various information pertaining to an architectural structure. This can be the suitable tool for effectively utilizing the various requests of both the users and the administrators from the planning phase. In particular, planning and constructing a school facility can be challenging because it is an important learning facility where the students are required follow a set schedule. Accommodating to the various needs and requests of the users and the other related parties in the progress can be very difficult. Therefore, in order to use the BIM with the basis of data to manage the lifetime of the school facility, it is necessary to develop the specialized BIM process customized to the school facilities. Using this as the base, the BIM process specifically for school facilities should be phased in, applied, and expanded. The objective of this study is to define the scope of application and to plan for the efficient utilization of the BIM process specialized for school facilities, when conducting the project from planning phase to design development phase through the series of processes. Unlike the presently used enhancement of the visible minute details of the models, the methods to enhance the quality of information contained inside the model will be proposed. Also, the user will participate in the school facility construction. The realistic BIM application is aimed through the research for the processes for building models that will be utilized for construction and management.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.379-386
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• 2016

This study explored Korean college students' smartphone game behavior for the pastime. Smartphone games have weakness that is not appropriate for playing the game because of small screen and non-sophisticated interface for operation. To defeat the disadvantage, the games employed minimalism like conciseness or simplicity. The study explored how conciseness influences perceived ease of use, perceived enjoyment, flow, and intent to use the game through PLS path modeling. We found that every hypothesis except a path, perceived ease of use to flow, proved significant. This result means that smartphone game design should consider the interface of users' convenience and user experience practically. Finally, based on the findings, suggestions for future studies were discussed.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.4
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• pp.441-454
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• 2008

Shipyard design and equipments layout problem, which are directly linked with the productivity of ship production, is an important issue serving as reference data of production plan for later massive production of ships. So far in many cases, design of a shipyard has been relying on the experienced engineers in shipbuilding, resulting in sporadic and poorly organized processes. And thus, economic losses as well as trials and errors in that accord have been pointed out as inevitable problems. This paper extracts a checklist of major elements to fine tune the shipbuilding yard designing process and the input/output data based on the simulation based shipbuilding yard layout designing framework and methodology proposed in existing researches, and executed initial architecture to develop software that integrates all the relevant processes and designing tools. In this course, both user request and design data by the steps are arranged and organized in the proposed layout design template form. In addition, simulation is done based on the parent shipbuilding process planning and scheduling data of the ship product, shipbuilding process and work stage facilities that constitute shipbuilding yard, and design items are verified and optimized with the layout and equipment list showing optimal process planning and scheduling effects. All the contents of this paper are based on simulation based shipbuilding yard layout designing methodology, and initial architecture processes are based on object oriented development methodology and system engineering methods.

• The Transactions of the Korea Information Processing Society
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• v.4 no.5
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• pp.1243-1256
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• 1997

Object modeling has been cinsidered as an efficient technique for eleciting user requirements and communicat-ing between developers and customers. But model itself is not easy to understand what recult will be after coding and whether it will be meet with the requirements of customers. In this paper, we developed the envuroment for visualization of object model for validating with rewuirnent at the early stage. Therefore, we defined correct and complete rules which can transform the object model.the delierables of Shler/Mellor's method, into a for-mal specification language of VDM(Vienna Development Methods) with a mathematical basis. This basis provides the means of proving that a specification is realizable and proving properties of a system.Therefore.the completeness, preciceness of object model can be verified by proving the transformed VDM specification and prototyping by constructing a visualization supporting enviroment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.147-154
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• 2015

Recently agile development process became increasing effectiveness, quality, attention to experts in customer satisfaction, as evidenced in this methodology when selecting projects promoting productive efficiency. With regard to contemporary needs and user requirements on the methodology selected to meet this paper is the product based Cross functional team suggested methodology Feature Team model to solve problems of this model, and organizing the Cross functional team, this team but this outcome (product) basis, were examined for the model that points to progress the development across multiple product as a functional unit, value-driven agile project through the Skills-based model and proposed a difference. And it examined the Agile Maturity metrics. PRINCE2 Agile Health-check entries future development direction of Agile techniques is a requirement of the project outset has studied the subject objective evaluation by the assumption that they can be changed at any time, not fixed this way and for the project team through research The proposed.

• The Journal of Korean Association of Computer Education
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• v.15 no.2
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• pp.57-66
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• 2012

It is the advantage of robot programming to improve the learners' interest. However, the drawback is existed in the fact that it is not easy to determine whether the problem lies in the hardware factor or programmed logic when an error takes place. This study is an attempt to develop a simulation tool which assists learners to concentrate on the problems not relating to robot assembling but to robot program. It aims to enable beginners make a sketch of their ideas and examine their logic through simulation. Therefore, an Etoys-based robot programming tool is developed to allows user to download and execute the simulated program into an assembled robot. The significance of this study is that easy activity of sketch-based simulation can support learners to understand how the principles of computer science are applied in daily life such as an automatic door system.