• 제목/요약/키워드: computer models

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사진측량과 컴퓨터비전 간의 카메라 렌즈왜곡 변환 (Conversion of Camera Lens Distortions between Photogrammetry and Computer Vision)

  • 홍송표;최한승;김의명
    • 한국측량학회지
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    • 제37권4호
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    • pp.267-277
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    • 2019
  • 사진측량과 컴퓨터비전 분야는 카메라에서 촬영된 영상에서 3차원 좌표를 결정하는 것은 동일하지만 두 분야는 카메라 렌즈왜곡 모델링 방법과 카메라 좌표계의 차이점으로 인하여 서로 간에 직접적인 호환이 어렵다. 일반적으로 드론 영상의 자료처리는 컴퓨터비전 기반의 소프트웨어를 이용하여 번들블록조정을 수행한 후 지도제작을 위해서 사진측량 기반의 소프트웨어로 도화를 수행하게 된다. 이때 카메라 렌즈왜곡의 모델을 사진측량에서 사용하는 수식으로 변환해야 하는 문제에 직면하게 된다. 이에 본 연구에서는 사진측량과 컴퓨터비전에서 사용되는 좌표계와 렌즈왜곡 모델식의 차이점에 대하여 기술하고 이를 변환하는 방법론을 제안하였다. 카메라 렌즈왜곡 모델의 변환식의 검증을 위해서 먼저 렌즈왜곡이 없는 가상의 좌표에 컴퓨터비전 기반의 렌즈왜곡 모델을 이용하여 렌즈왜곡을 부여하였다. 그리고 나서 렌즈왜곡이 부여된 사진좌표를 이용하여 사진측량 기반의 렌즈왜곡 모델을 이용하여 왜곡계수를 결정한 후 사진좌표에서 렌즈왜곡을 제거하여 원래의 왜곡이 없는 가상좌표와 비교하였다. 그 결과 평균제곱근거리가 0.5픽셀 이내로 양호한 것으로 나타났다. 또한 사진측량용 렌즈왜곡 계수를 적용하여 정밀도화 가능여부를 판단하기 위해서 에피폴라 영상을 생성하였다. 생성된 에피폴라 영상에서 y-시차의 평균제곱근오차가 계산한 결과 0.3픽셀 이내로 양호하게 나타났음을 알 수 있었다.

Three-Stage Framework for Unsupervised Acoustic Modeling Using Untranscribed Spoken Content

  • Zgank, Andrej
    • ETRI Journal
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    • 제32권5호
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    • pp.810-818
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    • 2010
  • This paper presents a new framework for integrating untranscribed spoken content into the acoustic training of an automatic speech recognition system. Untranscribed spoken content plays a very important role for under-resourced languages because the production of manually transcribed speech databases still represents a very expensive and time-consuming task. We proposed two new methods as part of the training framework. The first method focuses on combining initial acoustic models using a data-driven metric. The second method proposes an improved acoustic training procedure based on unsupervised transcriptions, in which word endings were modified by broad phonetic classes. The training framework was applied to baseline acoustic models using untranscribed spoken content from parliamentary debates. We include three types of acoustic models in the evaluation: baseline, reference content, and framework content models. The best overall result of 18.02% word error rate was achieved with the third type. This result demonstrates statistically significant improvement over the baseline and reference acoustic models.

A Study on Detection of Outliers and Influential Observations in Linear Models

  • Kang, Eun M.;Park, Sung H.
    • 품질경영학회지
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    • 제16권2호
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    • pp.18-33
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    • 1988
  • A new diagnostic statistic for detecting outliers and influential observations in linear models is suggested and studied in this paper. The proposed statistic is a weighted sum of two measures ; one is for detecting outliers and the other is for detecting influential ovservations. The merit of this statistic is that it is possible to distinguish outliers from influential observations. This statistic can be used for not only regression models but also factorial design models. A Monte Carlo simulation study is reported to suggest critical values for detecting outliers and influential observations for simple regression models when the number of observations is 11. 21, 31, 41 or 51.

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다중 프로세서 전전자 교환기의 구조 및 성능분석 (Architecture and performance analysis of multiprocessor ESS)

  • 박헌철;권욱현
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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    • pp.1026-1030
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    • 1987
  • This paper proposes analytic models of the large scale ESS's control system which has the multiprocessor architecture. The performance indices such as the ringback tone delay, busy tone delay, queue length and processor idletime are investigated through the analytic model. The system bottleneck is also analyzed. For the validation of analytic models, its simulation is performed using the SDL/SIM package for the case of 100,000 subscribers. From computer simulation, the results of analytic models are shown to be similar to the results of simulation models, which validates the analytic models.

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A Simultaneous Design of TSK - Linguistic Fuzzy Models with Uncertain Fuzzy Output

  • Kwak, Keun-Chang;Kim, Dong-Hwa
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.427-432
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    • 2005
  • This paper is concerned with a simultaneous design of TSK (Takagi-Sugeno-Kang)-linguistic fuzzy models with uncertain model output and the computationally efficient representation. For this purpose, we use the fundamental idea of linguistic models introduced by Pedrycz and develop their comprehensive design framework. The design process consists of several main phases such as (a) the automatic generation of the linguistic contexts by probabilistic distribution using CDF (conditional density function) and PDF (probability density function) (b) performing context-based fuzzy clustering preserving homogeneity based on the concept of fuzzy granulation (c) augment of bias term to compensate bias error (d) combination of TSK and linguistic context in the consequent part. Finally, we contrast the performance of the enhanced models with other fuzzy models for automobile MPG predication data and coagulant dosing process in a water purification plant.

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Study on The Development of Basic Simulation Network for Operational Transient Analysis of The CANDU Power Plant

  • Park, Jong-Woon;Lim, Jae-cheon;Suh, Jae-seung;Chung, Ji-bum;Kim, Sung-Bae
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1995년도 추계학술발표회논문집(1)
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    • pp.423-428
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    • 1995
  • Simulation models have been developed to predict the overall behavior of the CANDU plant systems during normal operational transients. For real time simulation purpose, simplified thermal hydraulic models are applied with appropriate system control logics, which include primary heat transport system solver with its component models and secondary side system models. The secondary side models are mainly used to provide boundary conditions for primary system calculation and to accomodate plant power control logics. Also, for the effective use of simulation package, hardware oriented basic simulation network has been established with appropriate graphic display system. Through validation with typical plant power maneuvering cases using proven plant performance analysis computer code, the present simulation package shows reasonable capability in the prediction of the dynamic behavior of plant variables during operational transients of CANDU plant, which means that this simulation tool can be utilized as a basic framework for full scope simulation network through further improvements.

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매크로 파라메트릭 방법론은 이용한 CAD 모델의 교환 (Exchange of CAD Models Using Macro Parametric Approach)

  • 문두환;한순흥
    • 한국CDE학회논문집
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    • 제6권4호
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    • pp.254-262
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    • 2001
  • It is not possible to exchange parametric information of CAD (Computer Aided Design) models based on the current version of STEP (Standard leer the Exchange of Product model data). The design intent can be lost during the STEP transfer of CAD models. The ISO Parametrics Group has proposed the SMCH (Solid Model Construction History) schema in June 2000 that includes structures fur exchange of parametric information. This paper proposes the macro parametric approach that is intended to provide capabilities to transfer parametric information. In this approach, CAD models are exchanged in the form of macro files. The macro file contains user commands which are used in the modeling phase. To exchange CAD models using the macro parametric approach, modeling commands of commercial CAD systems are analyzed. Those commands are classified by the grouping method suggested by Bill Anderson. As a neutral file format, a standard modeling commands set has been defined. Mapping relations between the standard modeling commands set and the native modeling commands set of commercial CAD systems are defined.

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A study on N-dimensional quad-tree decomposition

  • Yi, Cheon-Hee;Yi, Jae-Young
    • 반도체디스플레이기술학회지
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    • 제8권1호
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    • pp.43-48
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    • 2009
  • We have examined the problem of the number of quad-tree blocks that an n-dimensional rectangle will be decomposed into on the average. the contribution of this paper are both practical and theoretical. In this paper, we develops the overlapping multi-scale models and the region quad-tree models which is useful in computer graphics animation, image processing, pattern recognition and also for modeling three dimensional objects. These models, which represent something of a conceptual departure from other models developed for multi-scale framework were developed with the specific interest of producing smooth estimates.

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Models and Simulation of the Switched Reluctance Motor Drive System

  • Hao Chen;Ahn, Jin-Woo
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • 제2B권4호
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    • pp.201-206
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    • 2002
  • The paper presents the component parts and their models of the Switched Reluctance motor drive system with the angle position-current chopping control and with the fixed angle pulse width modulation control. The calculation of the parameters and the simulated models based on the MATLAB SIMULINK software package are introduced by a four-phase 816 structure prototype with the four-phase asymmetric bridge power converter. The simulation of the prototype in the course of starting is made by the simulated models at the different control strategies and the different given rotor speed.