• 대한전자공학회논문지
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• 제27권3호
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• pp.101-107
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• 1990

본 논문에서 유한차분법을 이용하여 Pt-GaAs Schottky Barrier Diode(SBD)를 일차원으로 simulation하였다. 반도체의 지배방정식인 포아송 방정식(poisson equation)과 전류연속 방정식)current continuity equation)을 이산화 시킨 다음 Newton-Raphson 방법으로 선형화시켜서 가우스 소거법으로 해가 수렴할 때까지 반복적으로 풀었다. 이 SBD의 해석에 필요한 경계조건은 열전자방출-확산이론(thermionic emission-diffusion theory)으로부터 Schottky Barrier의 경계조건을 취하였다. 에피층을 갖는 SBD를 모델링하여 인가전압에 따른 다이오드에서의 전위와 전자의 분포를 simulation 하였다. 전위에 따라 변하는 접속층을 고려하여 실험치와 잘 일치하는 결과를 얻었다.

• 한국CDE학회논문집
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• 제14권6호
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• pp.415-423
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• 2009

Because of the fast changing car design and increasing facilities, manufacturing process of cars is getting more complex now a days. Particularly, car manufacturing system that consist of automated devices, applies various simulation techniques to validate device motion and detect collision. To cope with this problem, traditional manufacturing system deployed test-run with the real devices. However, increased computing power in a contemporary manufacturing system changes it into realistic 3D simulation environment. Similarly, managed device data that was generated using 2D traditionally, can be converted to 3D realistic simulation. The existing problem with 3D simulation is disjoint data interaction between different work stations. Consequently, JIGs, fixing the car part accurately, are changed according to fixing position on the part or a part shape properties. In practice, the 3D JIG data has to be managed according to kinematic information, but not of its features. However, generating kinematic information to the 3D model repeatedly according to frequent change in part is not explained in current literatures. To fill this knowledge gap, this paper suggests an improving method of rendering 3D JIG kinematics information to simulation model. Thereafter, it shows the result of implementation.

• 인터넷정보학회논문지
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• 제10권6호
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• pp.191-203
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• 2009

시뮬레이션은 어떤 문제를 모의적으로 실험하여 그 특성을 파악하는 작업이다. 시뮬레이션 과정에서는 시뮬레이션 모델, 알고리즘, 입출력 데이터의 교체 및 변경이 빈번하게 발생한다. 특히 알고리즘의 교체를 통한 시뮬레이션 작업의 경우 알고리즘을 구현한 컴포넌트가 교체될 때 기능적으로 정확하게 동작하지 않는다면 시뮬레이션 작업을 성공적으로 수행하기 어렵다. 이 논문에서는 소프트웨어 기반 위성항법 시뮬레이션 환경에서 교체될 컴포넌트가 기능적으로 정확하게 구현되어 있는지를 검증하기 위한 테스트 프레임워크를 제안한다. 이 프레임워크는 컴포넌트가 교체되는 시점에서 교체되는 컴포넌트의 상황에 맞게 기능 테스트를 수행할 수 있게 해준다.

• 대한원격탐사학회지
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• 제24권5호
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• pp.497-506
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• 2008

The needs for digital models of real environment such as 3D terrain or cyber city model are increasing. Most of applications related with modeling and simulation require virtual environment constructed from geospatial information of real world in order to guarantee reliability and accuracy of the simulation. The most fundamental data for building virtual environment, terrain elevation and orthogonal imagery is acquired from optical sensor of satellite or airplane. Providing interoperable and reusable digital model is important to promote practical application of high-resolution satellite imagery. This paper presents the new research regarding representation of geospatial information, especially for 3D shape and appearance of virtual terrain. and describe framework for constructing real-time 3D model of large terrain based on high-resolution satellite imagery. It provides infrastructure of 3D simulation with geographical context. Web architecture, XML language and open protocols to build a standard based 3D terrain are presented. Details of standard-based approach for providing infrastructure of real-time 3D simulation using high-resolution satellite imagery are also presented. This work would facilitate interchange and interoperability across diverse systems and be usable by governments, industry scientists and general public.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.639-640
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• 2015

Traditional construction planning based on historical data and heuristic adjustment can no longer incorporate all the operational details and guarantee the expected performance. The variation between the expected and the actual production leads to cost overruns or delay. Although predicting reliable productivity on construction site is getting more important, the difficulty of this increases. In this regard, this paper suggested to develop BIM-integrated simulation framework. This framework could predict productivity dynamics by considering factors affecting on construction productivity at operational phase. We developed the following processes; 1) enabling a BIM model to produce input data for simulation; 2) developing the construction operation simulation; 3) running simulation using BIM data and obtaining productivity results. The BIM-integrated simulation framework was tested with structural steel erection model because steel erection work is one of the most critical process influencing on the whole construction budget and duration. We could improve to predict more dynamic productivity from this framework, and this reliable productivity helps construction managers to optimize resource allocation, increase schedule reliability, save storage cost, and reduce material loss.

• 한국산업융합학회 논문집
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• 제8권1호
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• pp.11-17
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• 2005

This study was performed to analysis the operation process when fabric pattern design was done by the use of CAD system compared with the manual work in order to determine the operation efficiency with the application of fabric design CAD system. The results of the study were as follows: 1. since 160,000 colors were supported by CAD system, color proposed by consumer was able to match exactly according to the its design. However, exact color matching was not possible by manual work. 2. Woven state of back of pattern design could be identified simultaneously with face of it for CAD system, while face and back of the fabrics should be designed separatedly in case of manual work. 3. Since the combination of warp and filling yarn was compatible with the fabric density in one repeat unit in CAD system, exact size of pattern design to be woven was able to expressed. 4. Only simple graphical expression by manual work was seen, while with the CAD system, texture and shade effect as well as graphical expression could be expressed and so fault could be reduced in advance with the simulation of actual feeling of fabrics in the screen. In conclusion, when CAD system will be introduced to the textile industry, operation time of designing pattern can be reduced. Since the operation is easy and simple, a beginner can operate CAD system easily. Thus, production and wage costs can be saved and this can be related directly with the improvement of productivity which is the main purpose of introducing CAD system.

• Journal of Ship and Ocean Technology
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• 제5권1호
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• pp.1-13
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• 2001

As Indonesia determines to increase its marine fishery production, the development of tradi-tional boatyards has to be included in the agenda as it will give the local fishing communities a better chance to compete with large capital intensive fishing companies. It will also spread job opportunities evenly throughout the country instead of concentration fishing vessel con- struction in a few large shipyards located primarily on the highly populated island of Java. However development every single boatyard in indonesia would not only be prohibitively ex-pensive, but it would also create social tensions as the introduced technology would not be immediately accepted by the rural societies whose own traditions are still culturally signif-icant. Both these problems can be reduced by developing a collaborative scheme between traditional boatyards and a larger shipyard. The shipyard, with modern facilities, can develop work packages containing knock down components which are then assembled in the tradi-tional boatyards. The work packages are planned and designed so that every component can be assembled with relatively simple tools. Radical changes can be avoided as new techniques can be introduced gradually, responding to the boatyard\\`s own requirements and aspirations. While this manufacturing procedure is conceptually straightforward its efficient implemen-tation is in practice complicated by the fact that each traditional boatyard has unique char-acteristics in terms of labour resources, technological capability, and transportation links. By developing a computer model to simulate the interaction between the main shipyard and small traditional a computer model to simulate the interaction between the main shipyard and small traditional boatyards work packages can be designed that ensure that activities at all manufacturing locations are efficient.

• Journal of Communications and Networks
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• 제18권3호
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• pp.523-530
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• 2016

We use both theoretical analysis and simulations to study the impact of crosspoint-queued (CQ) buffer size on CQ switch throughput and delay performance under different traffic models, input loads, and scheduling algorithms. In this paper, we present the following. 1) We prove the stability of CQ switch using any work-conserving scheduling algorithm. 2) We present an exact closed-form formula for the CQ switch throughput and a non-closed-form but convergent formula for its delay using static non-work-conserving random scheduling algorithms with any given buffer size under independent Bernoulli traffic. 3) We show that the above results can serve as a conservative guide on deciding the required buffer size in pure CQ switches using work-conserving algorithms such as the random scheduling, under independent Bernoulli traffic. 4) Furthermore, our simulation results under real-trace traffic show that simple round-robin and random work-conserving algorithms can achieve quite good throughput and delay performance with a feasible crosspoint buffer size. Our work reveals the impact of buffer size on the CQ switch performance and provides a theoretical guide on designing the buffer size in pure CQ switch, which is an important step toward building ultra-high-speed switch fabrics.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.71-72
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• 2023

Asbestos is a durable and heat-resistant building material used in various building materials such as slate, ceiling tex, and spray paint. It has been banned since 2009 after found to be a first-class carcinogen that causes various cancers and asbestos lung disease. Since workers are likely to be exposed to asbestos in the process of dismantling and removal of asbestos-made building materials and facilities, laws and work standards are proposed by the Ministry of Employment and Labor to ensure the safety of asbestos dismantling work. In addition, prior studies on exposure levels and analysis methods have been conducted in this regard mainly for residents. However, the relation between the results of the risk assessment of the process conducted during the asbestos investigation and the work is still ambiguous for the safety of workers. Therefore, this study proposes a process model development methodology that considers work risk based on the results of a survey from asbestos dismantling companies.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.61.1-61.1
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• 2015

Nanoscale semiconductor plasma processing has become one of the most challenging issues due to the limits of physicochemical fabrication routes with its inherent complexity. The mission of future and emerging plasma processing for development of next generation semiconductor processing is to achieve the ideal nanostructures without abnormal profiles and damages, such as 3D NAND cell array with ultra-high aspect ratio, cylinder capacitors, shallow trench isolation, and 3D logic devices. In spite of significant contributions of research frontiers, these processes are still unveiled due to their inherent complexity of physicochemical behaviors, and gaps in academic research prevent their predictable simulation. To overcome these issues, a Korean plasma consortium began in 2009 with the principal aim to develop a realistic and ultrafast 3D topography simulator of semiconductor plasma processing coupled with zero-D bulk plasma models. In this work, aspects of this computational tool are introduced. The simulator was composed of a multiple 3D level-set based moving algorithm, zero-D bulk plasma module including pulsed plasma processing, a 3D ballistic transport module, and a surface reaction module. The main rate coefficients in bulk and surface reaction models were extracted by molecular simulations or fitting experimental data from several diagnostic tools in an inductively coupled fluorocarbon plasma system. Furthermore, it is well known that realistic ballistic transport is a simulation bottleneck due to the brute-force computation required. In this work, effective parallel computing using graphics processing units was applied to improve the computational performance drastically, so that computer-aided design of these processes is possible due to drastically reduced computational time. Finally, it is demonstrated that 3D feature profile simulations coupled with bulk plasma models can lead to better understanding of abnormal behaviors, such as necking, bowing, etch stops and twisting during high aspect ratio contact hole etch.