• Title/Summary/Keyword: modeling errors

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Tolerance Analysis on 3-D Object Modeling Errors in Model-Based Camera Tracking (모델 기반 카메라 추적에서 3차원 객체 모델링의 허용 오차 범위 분석)

  • Rhee, Eun Joo;Seo, Byung-Kuk;Park, Jong-Il
    • Journal of Broadcast Engineering
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    • v.18 no.1
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    • pp.1-9
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    • 2013
  • Accuracy of the 3-D model is essential in model-based camera tracking. However, 3-D object modeling requires dedicated and complicated procedures for precise modeling without any errors. Even if a 3-D model contains a certain level of errors, on the other hand, the tracking errors cause by the modeling errors can be different from its perceptual errors; thus, it is an important aspect that the camera tracking can be successful without precise 3-D modeling if the modeling errors are within the user's permissible range. In this paper, we analyze the tolerance of 3-D object modeling errors by comparing computational matching errors with perceptual matching errors through user evaluations, and also discuss permissible ranges of 3-D object modeling errors.

Subjective Evaluation on Perceptual Tracking Errors from Modeling Errors in Model-Based Tracking

  • Rhee, Eun Joo;Park, Jungsik;Seo, Byung-Kuk;Park, Jong-Il
    • IEIE Transactions on Smart Processing and Computing
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    • v.4 no.6
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    • pp.407-412
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    • 2015
  • In model-based tracking, an accurate 3D model of a target object or scene is mostly assumed to be known or given in advance, but the accuracy of the model should be guaranteed for accurate pose estimation. In many application domains, on the other hand, end users are not highly distracted by tracking errors from certain levels of modeling errors. In this paper, we examine perceptual tracking errors, which are predominantly caused by modeling errors, on subjective evaluation and compare them to computational tracking errors. We also discuss the tolerance of modeling errors by analyzing their permissible ranges.

A Study on the Robust Control of Systems Dominantly Subkected to Modeling Errors and Uncertainties (모델링오차와 불확실성을 지배적으로 받는 시스템의 강인한 제어에 관한 연구)

  • 김종화
    • Journal of Advanced Marine Engineering and Technology
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    • v.19 no.2
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    • pp.67-80
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    • 1995
  • In order to control systems which are dominantly subjected to modeling errors and uncertainties, control strategies must deal with the effect of modeling errors and uncertainties. Since most of control methods based on system mathematical model, such as LQG/LTR method, have been developed mainly focused on stability robustness, they can not smartly improve the transient response disturbed by modeling errors and/or uncertainties. In this research, a fuzzy PID control method is suggested, which can stably improve the transient responses of systems disturbed by modeling errors as well as systems not entirely using mathematical models. So as to assure the effectiveness of suggested control method, computer simulations are accomplished for some example systems, through the comparison of transient responses.

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Design of Screening Inspection Procedures Based on Guard Bands Considering Measurement Errors (측정오류를 고려한 가드밴드 기반 스크리닝 검사방식의 설계)

  • Kim, Young Jin
    • Journal of Korean Society for Quality Management
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    • v.41 no.4
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    • pp.673-681
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    • 2013
  • Purpose: The purpose of this study is to investigate the design optimization modeling of screening procedures based on the assessment of misclassification errors. Methods: Misclassification errors due to measurement variability are derived for normally distributed quality characteristics. Further, an optimization model for ensuring the level of outgoing quality is proposed and demonstrated through an illustrative example. Results: It is shown that two types of misclassification errors (i.e., false acceptance and false rejection) may be properly compromised through an analytical assessment of measurement errors and an optimization modeling. It is also discussed that a variety of optimization modeling may be enabled based on the derivation of measurement errors. Conclusion: It may be concluded that the design of screening inspection may further be facilitated by including the effect of measurement errors on the performance of screening inspection procedure.

Damage Detection for Bridges Considering Modeling Errors (모델링 오차를 고려한 교량의 손상추정)

  • 윤정방;이종재;이종원;정희영
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.04a
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    • pp.300-307
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    • 2002
  • Damage estimation methods are classified into two groups according to the dependence on the FE model : signal-based and model-based methods. Signal-based damage estimation methods are generally appropriate for detection of damage location, whereas not effective for estimation of damage severities. Model-based damage estimation methods are difficult to apply directly to the structures with a large number of the probable damaged members. It is difficult to obtain the exact model representing the real bridge behavior due to the modeling errors. The modeling errors even may exceed the modal sensitivity on damage. In this study, Model-based damage detection method which can effectively consider the modeling errors is suggested. Two numerical example analyses on a simple beam and a multi-girder bridge are presented to demonstrate the effectiveness of the presented method.

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Influence of Modeling Errors in the Boundary Element Analysis of EEG Forward Problems upon the Solution Accuracy

  • Kim, Do-Won;Jung, Young-Jin;Im, Chang-Hwan
    • Journal of Biomedical Engineering Research
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    • v.30 no.1
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    • pp.10-17
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    • 2009
  • Accurate electroencephalography (EEG) forward calculation is of importance for the accurate estimation of neuronal electrical sources. Conventional studies concerning the EEG forward problems have investigated various factors influencing the forward solution accuracy, e.g. tissue conductivity values in head compartments, anisotropic conductivity distribution of a head model, tessellation patterns of boundary element models, the number of elements used for boundary/finite element method (BEM/FEM), and so on. In the present paper, we investigated the influence of modeling errors in the boundary element volume conductor models upon the accuracy of the EEG forward solutions. From our simulation results, we could confirm that accurate construction of boundary element models is one of the key factors in obtaining accurate EEG forward solutions from BEM. Among three boundaries (scalp, outer skull, and inner skull boundary), the solution errors originated from the modeling error in the scalp boundary were most significant. We found that the nonuniform error distribution on the scalp surface is closely related to the electrode configuration and the error distributions on the outer and inner skull boundaries have statistically meaningful similarity to the curvature distributions of the boundary surfaces. Our simulation results also demonstrated that the accumulation of small modeling errors could lead to considerable errors in the EEG source localization. It is expected that our finding can be a useful reference in generating boundary element head models.

Diagnostic System of Modeling Errors Generated from IGES CAD Data Exchange (IGES CAD 데이터의 교환에서 오류 진단 시스템)

  • Park, Sang-Ho;Park, Jong-Wook;Han, Soon-Heung;Choi, Young;Yang, Jung-Sam;Lee, Byung-Hoon
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.10
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    • pp.218-225
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    • 2003
  • A diagnostic system has been developed which reports modeling errors generated when exchanging CAD data using IGES (Initial Graphics Exchange Specification) format. The system determines whether the CAD data contains errors. It also helps to define the criteria for determining the integrity and interoperability of CAD data with downstream applications of another CAD/CAM/CAE/PDM systems. The methodology of our algorithms is to analyze IGES model data by identifying errors and anomalies with respect to the diagnosis of geometry and topology. The GUI (Graphic User Interface) of the developed system helps users to input values and to visualize diagnostic results at real time.

Development of an Entity-Relationship Modeling System for Designing Relational Database (관계형 데이터베이스 설계를 위한 개체 - 관계 모델링 시스템 개발)

  • Yoo, Jae-Gun
    • IE interfaces
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    • v.16 no.spc
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    • pp.45-48
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    • 2003
  • Entity-relationship modeling for designing relational database is a very complicated thinking process that requires extensive knowledge and experiences. It is very likely that designers make mistakes in this process. In order to minimize the mistakes, a systematic method to guide the thinking process is needed. In this research, an entity-relationship modeling system is developed, which resolves the whole process of information modeling, data modeling, and functional dependency relationship analysis into small and simple decision-making steps. Therefore, it can reduce the possibility of making decision errors and improve the efficiency of the modeling process. It's functionality and efficiency is verified through some modeling examples. It is expected that the modeling system can be commercialized, if some functions are added, such as detection, warning, and correction of decision errors, and educational help.

Verification of STL using the Triangle Based Geometric Modeler (삼각형기반 형상모델러를 이용한 STL의 검증)

  • 채희창
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.1
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    • pp.51-58
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    • 1997
  • The verification of the STL file is essential to build the confident parts using a RP machine, because the STL file obtained from the CAD software has many errors-the orientation of triangle does not coincide with adjacent triangles or some triangles are omitted, overlpped and so forth. Especially, the STL file translated from the surface model has more errors than those translated from the solid model. In this study, all possible errors were classified with the most general from and the causes of errors were analyzed to verify and correct errors. Using the triangle based non-manifold geometric modeling, these errors were corrected. Especially, this study took the notice of the problem about the intersected triangles and non-manifold properties overlooked in the previous studies. But this study has a penalty on computing time of $O(n^2)$.

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