• Title/Summary/Keyword: Simulation operation

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DEVELOPMENT OF THREE DIMENSIONAL MEASURING PROGRAM WITH FRONTAL AND LATERAL CEPHALOMETRIC RADIOGRAPHS -PART 2. 3-D VISUALIZATION AND MEASURMENT PROGRAM FOR MAXILLOFACIAL STRUCTURE- (정모 및 측모 두부 방사선 규격사진을 이용한 3차원 계측 프로그램의 개발 -2. 악안면 구조에 대한 3차원적 시각화 및 측정프로그램 개발-)

  • Lee, Sang-Han;Mori, Yoshihide;Minami, Katsuhiro;Lee, Geun-Ho;Kwon, Tae-Geon
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.27 no.4
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    • pp.321-329
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    • 2001
  • To establish systematic diagnosis and treatment planning of dentofacial deformity patient including facial asymmetry or hemifacial microsomia patient, comprehensive analysis of three dimensional structure of the craniofacial skeleton is needed. Even though three dimensional CT has been developed, landmark identification of the CT is still questionable. In recent, a method for correcting cephalic malpositioning that enables accurate superimposition of the landmarks in different stages without using any additional equipment was developed. It became possible to compare the three-dimensional positional change of the maxillomandible without invasive procedure. Based on the principle of the method, a new program was developed for the purpose of diagnosis and treatment planning of dentofacial deformity patient via three dimensional visualization and structural analysis. This program enables us to perform following menu. First, visualization of three dimensional structure of the craniofacial skeleton with wire frame model which was made from the landmarks observed on both lateral and frontal cephalogram. Second, establishment of midsagittal plane of the face three dimensionally, with the concept of "the plane of the best-fit". Third, examination of the degree of deviation and direction of deformity of structure to the reference plane for the purpose of establishing surgical planning. Fourth, simulation of expected postoperative result by various image operation such as mirroring, overlapping.

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A Study on Effective Moving Object Segmentation and Fast Tracking Algorithm (효율적인 이동물체 분할과 고속 추적 알고리즘에 관한 연구)

  • Jo, Yeong-Seok;Lee, Ju-Sin
    • The KIPS Transactions:PartB
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    • v.9B no.3
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    • pp.359-368
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    • 2002
  • In this paper, we propose effective boundary line extraction algorithm for moving objects by matching error image and moving vectors, and fast tracking algorithm for moving object by partial boundary lines. We extracted boundary line for moving object by generating seeds with probability distribution function based on Watershed algorithm, and by extracting boundary line for moving objects through extending seeds, and then by using moving vectors. We processed tracking algorithm for moving object by using a part of boundary lines as features. We set up a part of every-direction boundary line for moving object as the initial feature vectors for moving objects. Then, we tracked moving object within current frames by using feature vector for the previous frames. As the result of the simulation for tracking moving object on the real images, we found that tracking processing of the proposed algorithm was simple due to tracking boundary line only for moving object as a feature, in contrast to the traditional tracking algorithm for active contour line that have varying processing cost with the length of boundary line. The operations was reduced about 39% as contrasted with the full search BMA. Tracking error was less than 4 pixel when the feature vector was $(15\times{5)}$ through the information of every-direction boundary line. The proposed algorithm just needed 200 times of search operation.

A Study on Hierarchical Overlay Multicast Architecture in Mobile Ad Hoc Networks (Mobile Ad Hoc 네트워크를 위한 계층적 오버레이 멀티캐스트 구조 연구)

  • Kim, Kap-Dong;Park, Jun-Hee;Lee, Kwang-Il;Kim, Hag-Young;Kim, Sang-Ha
    • The KIPS Transactions:PartC
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    • v.13C no.5 s.108
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    • pp.627-634
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    • 2006
  • Overlay network eliminates the need to change the application-layer tree when the underlying network changes and enables the overlay network to survive in environments where nonmember nodes do not support multicast functionality. An overlay protocol monitors group dynamics, while underlying unicast protocols track network dynamics, resulting in more stable protocol operation and low control overhead even in a highly dynamic environment. But, if overlay multicast protocols does not know the location information of node, this makes it very difficult to build an efficient multicasting tree. So, we propose a Hierarchical Overlay Multicast Architecture (HOMA) with the location information. Because proposed architecture makes static region-based dynamic group by multicast members, it is 2-tired overlay multicasts of application layer that higher layer forms overlay multicast network between members that represent group, and support multicast between multicast members belonging to region at lower layer. This use GPS, take advantage of geographical region, and realizes a region-sensitive higher layer overlay multicast tree which is impervious to the movements of nodes. The simulation results show that our approach solves the efficiency problem effectively.

Plant-wide On-line Monitoring and Diagnosis Based on Hierarchical Decomposition and Principal Component Analysis (계층적 분해 방법과 PCA를 이용한 공장규모 실시간 감시 및 진단)

  • Cho Hyun-Woo;Han Chong-hun
    • Journal of the Korean Institute of Gas
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    • v.1 no.1
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    • pp.27-32
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    • 1997
  • Continual monitoring of abnormal operating conditions i a key issue in maintaining high product quality and safe operation, since the undetected process abnormality may lead to the undesirable operations, finally producing low quality products, or breakdown of equipment. The statistical projection method recently highlighted has the advantage of easily building reference model with the historical measurement data in the statistically in-control state and not requiring any detailed mathematical model or knowledge-base of process. As the complexity of process increases, however, we have more measurement variables and recycle streams. This situation may not only result in the frequent occurrence of process Perturbation, but make it difficult to pinpoint trouble-making causes or at most assignable source unit due to the confusing candidates. Consequently, an ad hoc skill to monitor and diagnose in plat-wide scale is needed. In this paper, we propose a hierarchical plant-wide monitoring methodology based on hierarchical decomposition and principal component analysis for handling the complexity and interactions among process units. This have the effect of preventing special events in a specific sub-block from propagating to other sub-blocks or at least delaying the transfer of undesired state, and so make it possible to quickly detect and diagnose the process malfunctions. To prove the performance of the proposed methodology, we simulate the Tennessee Eastman benchmark process which is operated continuously with 41 measurement variables of five major units. Simulation results have shown that the proposed methodology offers a fast and reliable monitoring and diagnosis for a large scale chemical plant.

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A Study on Enhancement Method of Hosting Capacity for PV System Based on Primary Feeder Reconfiguration (배전선로 절체에 의한 태양광전원의 수용성 향상방안에 관한 연구)

  • Lee, Myung-Geun;Lee, Hu-Dong;Ferreira, Marito;Park, Ji-Hyun;Tae, Dong-Hyun;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.11
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    • pp.239-249
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    • 2019
  • Recently, the Korean government has implemented a policy to expand renewable energy sources. Large-scale PV systems are being actively interconnected with the distribution system. On the other hand, when a large-scale PV system is installed and operated, the customer voltages could violate the allowable voltage limit due to reverse power flow of the PV system. To overcome these problems, an enhancement method for hosting the capacity of the PV system in a distribution system is being actively conducted. Therefore, to improve the hosting capacity of the PV system, this paper proposes a model of a reconfiguration of the distribution system, which is composed of three sections and three connections based on PSCAD/EMTDC S/W, and proposes an evaluation algorithm for the feeder reconfiguration to maximize an adaption of the PV system. In addition, this paper presents the optimal method of the feeder reconfiguration section to evaluate the maximum capacity of the PV system to keep customer voltages within the allowable voltage limits based on various operation scenarios, such as the capacity of a PV system and section of feeder reconfiguration. From the simulation results based on the PSCAD/EMTDC modeling and evaluation algorithm, it was confirmed that they are a useful and practical tool to enhance hosting the capacity of a PV system in a distribution system.

Simulator for 3 Phase Induction Motor with LCL Filter and PWM Rectifier (LCL 필터와 PWM 정류기를 이용한 3상 유도전동기의 시뮬레이터)

  • Cho, Kwan Yuhl;Kim, Hag Wone
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.11
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    • pp.861-869
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    • 2020
  • A dynamo set for a high-power induction motor drive is expensive and needs a long time to manufacture. Therefore, the development of a simulator that functions as the induction motor and load equipment is required. A load simulator of an inverter for a high-power three-phase induction motor consists of a reactor and three-phase PWM inverter. Therefore, it cannot simulate the dynamic characteristics of an induction motor and functions only as a load. In this paper, a real-time simulator is proposed to simulate a model of an induction motor and the load characteristics based on an LCL filter and three-phase PWM rectifier for a three-phase induction motor. The currents of a PWM inverter that simulate the stator currents of the motor are controlled by the inductor currents and capacitor voltages of the LCL filter. The capacitor voltages of the LCL filter simulate the induced voltages in the stator windings by the rotating rotor fluxes of the motor, and the capacitor voltages are controlled by the inductor currents and a PWM rectifier. The rotor currents, the stator and rotor flux linkages, the electromagnetic torque, the slip frequency, and the rotor speed are derived from the inverter currents and the motor parameters. The electrical and mechanical model characteristics and the operation of vector control were verified by MATLAB/Simulink simulation.

PR Controller Based Current Control Scheme for Single-Phase Inter-Connected PV Inverter (PR제어기를 이용한 단상 계통 연계형 태양광 인버터 설계)

  • Vu, Trung-Kien;Seong, Se-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.12
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    • pp.3587-3593
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    • 2009
  • Nowadays, the PV systems have been focused on the interconnection between the power source and the grid. The PV inverter, either single-phase or three-phase, can be considered as the core of the whole system because of an important role in the grid-interconnecting operation. An important issue in the inverter control is the load current regulation. In the literature, the Proportional+Integral (PI) controller, normally used in the current-controlled Voltage Source Inverter (VSI), cannot be a satisfactory controller for an ac system because of the steady-sate error and the poor disturbance rejection, especially in high-frequency range. By comparison with the PI controller, the Proportional+Resonant (PR) controller can introduce an infinite gain at the fundamental ac frequency; hence can achieve the zero steady-state error without requiring the complex transformation and the dq-coupling technique. In this paper, a PR controller is designed and adopted for replacing the PI controller. Based on the theoretical analyses, the PR controller based control strategy is implemented in a 32-bit fixed-point TMS320F2812 DSP and evaluated in a 3kW experimental prototype Photovoltaic (PV) power conditioning system (PCS). Simulation and experimental results are shown to verify the performance of implemented control scheme in PV PCS.

Sensitivity Analysis of Satellite BUV Ozone Profile Retrievals on Meteorological Parameter Errors (기상 입력장 오차에 대한 자외선 오존 프로파일 산출 알고리즘 민감도 분석)

  • Shin, Daegeun;Bak, Juseon;Kim, Jae Hwan
    • Korean Journal of Remote Sensing
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    • v.34 no.3
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    • pp.481-494
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    • 2018
  • The accurate radiative transfer model simulation is essential for an accurate ozone profile retrieval using optimal estimation from backscattered ultraviolet (BUV) measurement. The input parameters of the radiative transfer model are the main factors that determine the model accuracy. In particular, meteorological parameters such as temperature and surface pressure have a direct effect on simulating radiation spectrum as a component for calculating ozone absorption cross section and Rayleigh scattering. Hence, a sensitivity of UV ozone profile retrievals to these parameters has been investigated using radiative transfer model. The surface pressure shows an average error within 100 hPa in the daily / monthly climatological data based on the numerical weather prediction model, and the calculated ozone retrieval error is less than 0.2 DU for each layer. On the other hand, the temperature shows an error of 1-7K depending on the observation station and altitude for the same daily / monthly climatological data, and the calculated ozone retrieval error is about 4 DU for each layer. These results can help to understand the obtained vertical ozone information from satellite. In addition, they are expected to be used effectively in selecting the meteorological input data and establishing the system design direction in the process of applying the algorithm to satellite operation.

A Study on Digital Reinforcements for Efficient Automotive Design - With Emphasis on VR based CAID System - (자동차 디자인 효율화를 위한 디지털 강화요소 연구 - VR 기반 CAID 시스템을 중심으로 -)

  • Cho, Kyung-Sil;Lee, Myung-Ki
    • Archives of design research
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    • v.19 no.5 s.67
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    • pp.55-64
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    • 2006
  • As digital systems were introduced to automotive design in the mid 1980s, the design process has adopted many digital programs to save time compared to the conventional hand drafting. Digital technology was introduced not only to satisfy the reeds of the global environment, as the number of automobiles exported to many different parts of the world has increased, but also to save time and effort in developing several models of quality automobiles. Therefore, every automotive manufacturer in the world has expanded its virtual reality(VR) studio to establish visualization systems that visualize automobiles in the actual size and a co-operation system that enables simultaneous feedback from all of its design studios around the world. Unlike the existing design reviewing methos, the new improved feedback system is assessed as a reasonable method to evaluates and understand how the automobiles are actually manufactured in simulation. It is especially helpful when advanced products and concept cars require fast results. Other strengths of the new system include shorter development period, cost efficiency, no more manual labor, various designs within a short period of time, and realistic visualization of concepts. Large-scale products, including automobiles, need to be projected in the actual size and high clarity through the Power-wall System and are examined in a virtual space called a Cave. Therefore, it took much time to establish digital infrastructure. An infrastructure would constantly require system improvement and performance enhancement, but it is certain that now is the right time for the take-off to utilizing the strengths of digital design and improve the weaknesses. In this respect, this study provided an understanding of the importance of digital design based on digital reinforcements and examined an effective utilization of digital technology for an efficient development of automobiles in the future.

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Collision Avoidance and Deadlock Resolution for AGVs in an Automated Container Terminal (자동화 컨테이너 터미널에서의 AGV 충돌 방지 및 교착 해결 방안)

  • Kang, Jae-Ho;Choi, Lee;Kang, Byoung-Ho;Ryu, Kwang-Ryel;Kim, Kap-Hwan
    • Journal of Intelligence and Information Systems
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    • v.11 no.3
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    • pp.25-43
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    • 2005
  • In modern automated container terminals, automated guided vehicle (AGV) systems are considered a viable option for the horizontal tansportation of containers between the stacking yard and the quayside cranes. AGVs in a container terminal move rather freely and do not follow fixed guide paths. For an efficient operation of such AGVs, however, a sophisticated traffic management system is required. Although the flexible routing scheme allows us to find the shortest possible routes for each of the AGVs, it may incur many coincidental encounters and path intersections of the AGVs, leading to collisions or deadlocks. However, the computational cost of perfect prediction and avoidance of deadlocks is prohibitively expensive for a real time application. In this paper, we propose a traffic control method that predicts and avoids some simple, but at the same time the most frequently occurring, cases of deadlocks between two AGVs. More complicated deadlock situations are not predicted ahead of time but detected and resolved after they occur. Our method is computationally cheap and readily applicable to real time applications. The efficiency and effectiveness of our proposed methods have been validated by simulation.

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