• 한국정밀공학회지
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• 제18권2호
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• pp.90-95
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• 2001

f-$\theta$len is one of the important parts in Laser Scanning Unit because it affects on the optical performance of Laser Scanning Unit dominantly. It is necessary to find out the relationship between the surface profile error of f-$\theta$lens and the beam profile focusing on the Organic Photo Conductive drum in order to analysis the beam profile problems such as appearance of side lobe and expansion of center lobe. In this research, a simulation process which relates the surface profile characteristics to the beam profile has been developed by CODE V. The simulated beam profile also have been compared with the measurement results.

• 한국CDE학회논문집
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• 제22권1호
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• pp.1-9
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• 2017

This research develops dispatching rule for a wafer FABs with dedication constraints. Dedication, mostly considered in a photolithography step, is a feature in a modern FABs in order to increase the yield of machines and achieve the advance of manufacturing technology. However, the dedication has the critical problem because it causes dedication load of machines to unbalance. In this paper, we proposes the dedication load based dispatching rule for load balancing in order to resolve the problem. The objective of this paper is to balance dedication load of photo machines in wafer FABs with dedication constraint. Simulation experiments show that the proposed rule improves the performance of wafer FABs as well as load balance for dedication machines compared to open-loop control based conventional dispatching rule.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집
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• pp.17-20
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• 2004

PV model is presented based on the shockley diode equation. The simple model has a photo-current source, an single diode junction and a series resistance and includes temperature dependences. An accurate PV module electrical model is presented, matching with boost converter MPPT strategy and demosntarted in Matlab for a typical general purpose solar cell. Given solar insolation and temperature, the model returns current vector and MPP.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.32-33
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• 2010

This paper describes a droop control method for the autonomous operation of DC distribution system using distributed generations and energy storage. The method suppress the circulating current, and each unit could be controlled autonomously without communication system. Detailed model of wind power generation, photo-voltaic generation, fuel-cell generation and battery was implemented with the user-defined model of PSCAD/EMTDC software that is coded with C-language. The simulation and experimental results confirms that the proposed DC distribution system make it feasible to provide power to the load stably and verify effectiveness of the proposed method.

• 한국조경학회지
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• 제26권2호
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• pp.155-165
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• 1998

Cultural-historical places, due to their strong symbolic sense of place shared in various people, have important impacts on people's cognitive and emotional reactions. Especially, the visual characteristics of surrounding areas of cultural -historical places directly influence the way the places are perceived, because they function as a visual background of the places. This study examined how the visual characteristics of surrounding landscape of cultural-historical places nfluenced the perception of the places. The visual characteristics of the surrounding landscape was minipulated by a computer simulation in the two aspects; quality and scale. The quality of the simulated landscape was divided by two kinds : natural and artificial . The scale of the simulated landscape was classified by three kinds : 1/3 of the middle ground, 2/3, and 3/3. Specifically, in each photo simulation, simulated natural or artificial background was introduced up to 1/3, 2/3 or the full height of historic monument. After a computer simulation, people's cognitive and emotional reactions to the simulated slides were investigated. The results showed that the quality of surrounding landscape have a great impact on all the cognitive and emotional reactions investigated. On the vontrary, the scale of surrounding landscape was found to habve an impact on partial reactions, such as all the emotions, part of the cognitions, and visiting preference only. The results revealed that the visual characteristics of surrounding landscape should be considered as the crucial elements in planning of cultural-historical places. Based on the study results, several suggestions were made for the landscape planning and conservation for cultural-historical places and historic cities.

• 한국조경학회지
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• 제27권3호
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• pp.58-68
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• 1999

Purpose of this thesis is to find out the relationship among the amount of change and the visual cognition, and the visual preference which people like and can feel. Through the investigation of relationships between the amount of change, which indicates the degree of visual variation and the visual preference, the amount of change and the visual cognition, and the visual preference and the visual cognition, basic design data will be supplied, which can satisfy users' desire as much as possible in the most economic way. In order to investigate the relationship between the visually produced the amount of change and preferences, graphic simulation, in which variables other than the visual change are controlled, has been proceeded. Graphic factors of the visual change in the cyber exterior space are determined on the point of location (base plane, vertical plane, overhead plane), shape, size and color. As for the relationship between the amount of change and the preference, only the size is effective. since preferences on the location, shape and color are individual preferences, no common trend can be found. Therefore, we cannot say that which shape or color is better, Since the location, shape and color are qualitative change and the size is the quantitative change, the size can be the measurable change quantity. The relationship between the amount of change of size and the degree of preference is found to be inverse U-shape, i.e., as the amount of change of size increases the degree of preference first increases and, after a certain level, decreases. The same result has been obtained in photo simulation.

• 한국농공학회지
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• 제39권5호
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• pp.86-96
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• 1997

The arrangement of small streams in rural area, in the past times, attached importance to the prevention of flood damage through the straightening and lining of streams. Recently, the way of small stream arrangement is introducing the idea of water friendly environment or friendly space. As a result, there has been much concern with water favorable river management model which may lead to control flood. However, it is very difficult to develop a model applicable to all types of rivers, since each river has different flow velocity, flow amount and unique ecological characteristics. In this study, photo processing technique, one of landscape simulation methods, has been adopted because it helps to visually express and comprehensively evaluate pre and post scenery and easily applicable. Some important guideline and technique for the planning of small stream landscape arrangement are mentioned in this study. The simulation system for acquiring water favorable space and arranging landscapes needs to develop database which can forecast various types of landscape. It may also be used for the bases of planning and designing river environment arrangement. Computer aided image processing system enables to make selective planning in river environment arrangement. It may also enables to develop the methods for river environment development, ecology conservation, and multipurpose space utilization. Moreover, it makes economic river arrangement by applying river environment arrangement methods relevant to geographical characteristics. There are some limitations in this study, such as shortage of exact investigation on the stream direction and velocity in landscape arrangement. Continuous monitoring and research may be required to develop techniques through the application of computer graphics and digital image processing.

• 대한치과교정학회지
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• 제38권4호
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• pp.252-264
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• 2008

본 연구는 안면비대칭 환자의 악교정수술 시 경조직 이동에 따른 연조직 변화를 정면에서 평가함으로써 정면 얼굴 이미지 시뮬레이션 프로그램 개발에 도움이 되고자 시행되었다. 안면비대칭이 동반된 하악골 수술 예정 환자 45명을 대상으로 정모 두부방사선규격사진과 얼굴사진(photo)을 술전 및 술후에 각각 같은 각도로 촬영한 후, 술전 및 술후의 방사선사진을 이용하여 경조직 계측점의 변화를, 얼굴사진을 이용하여 연조직 계측점의 변화를 수평 및 수직으로 구분하여 각각 측정한 후 경조직 변화에 따른 연조직 변화를 비교 분석하였다. 연조직 변화와 경조직 변화의 상관성을 살펴본 결과 수평 방향, 수직 방향 모두에서 전반적으로 낮은 상관성을 보였으며, 1 : 1 mean ratio 산출을 위하여 서로 상관성이 가장 높은 경조직 계측점을 연조직 계측점별로 선택한 결과 직하방에 있는 경조직보다는 다소 멀리 떨어져 있는 경조직 계측점이 선택되는 경우가 많이 나타났다. 경조직 변화를 이용하여 연조직 변화를 예측할 수 있는 회귀방정식을 연조직 계측점별로 산출한 결과 연조직 수평변화 예측에 경조직 수직변화도 사용되고 연조직 수직변화 예측에 경조직 수평변화도 사용되었으며, 수평과 수직변화 모두에서 가장 설명력이 높은 방정식은 연조직 menton에서 나타났다. 이상의 연구결과 하부 경조직 계측점과 상부 연조직 계측점의 비율을 이용하는 1 : 1 mean ratio 방법은 불가능한 것으로 나타난 반면 회귀분석을 이용한 연조직 변화 예측은 임상에 도움이 될 수 있는 것으로 나타나 정면 이미지의 경우 컴퓨터를 이용한 시뮬레이션 프로그램이 반드시 필요함을 시사하였다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.75-82
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• 2015

This paper presents a new technique for enhancing power quality by reducing harmonics in the neutral conductor. Three-Phase Four-Wire (3P4W) system is commonly used where single and three phase loads are connected to Point of Common Coupling (PCC). Due to unbalance loads, the 3P4W distribution system becomes unbalance and current flows in the neutral conductor. If loads are non-linear, then the harmonic content of current will flow in neutral conductor. The neutral current that may flow towards transformer neutral point is compensated by using a series active filter. In order to reduce the harmonic content, the series active filter is connected in series with the neutral conductor by which neutral and phase current harmonics are reduced significantly. In this paper, solar PV based inverter circuit is proposed for compensating neutral current harmonics. The simulation is carried out in MATLAB/SIMULINK and also an experimental setup is developed to verify the effectiveness of the proposed method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.518-522
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• 2001

In recent years, natural energy has attracted growing interest because of environmental concerns. Many studies have been focused on photovoltaic power generation systems because of the ease of use in urban areas. On the conventional system, many photovoltaic modules (PV modules) are connected in series in order to obtain the sufficient DC-bus voltage for generating AC output voltage at the inverter circuit. However, the total generation power on the PV modules sometimes decreases remarkably because of the shadows that partially cover the PV modules. In order to overcome this drawback, an AC module strategy is proposed. On this system, a small power DC-AC utility interactive inverter is mounted on each PV module individually and the inverter operates so as to generate the maximum power from the corresponding PV module. This paper presents a novel flyback-type utility interactive inverter circuit suitable for AC module systems. The feature of the proposed system are, (1) small in volume and light in weight, (2) stable AC current injection, (3) enabling a small DC capacitor. The effectiveness of the proposed system is clarified through the simulation and the experiments.