• 제목/요약/키워드: actual error

검색결과 1,365건 처리시간 0.023초

A modified error-oriented weight positioning model based on DV-Hop

  • Wang, Penghong;Cai, Xingjuan;Xie, Liping
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제16권2호
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    • pp.405-423
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    • 2022
  • The distance vector-hop (DV-Hop) is one of the emblematic algorithms that use node connectivity for locating, which often accompanies by a large positioning error. To reduce positioning error, the bio-inspired algorithm and weight optimization model are introduced to address positioning. Most scholars argue that the weight value decreases as the hop counts increases. However, this point of view ignores the intrinsic relationship between the error and weight. To address this issue, this paper constructs the relationship model between error and hop counts based on actual communication characteristics of sensor nodes in wireless sensor network. Additionally, we prove that the error converges to 1/6CR when the hop count increase and tendency to infinity. Finally, this paper presents a modified error-oriented weight positioning model, and implements it with genetic algorithm. The experimental results demonstrate excellent robustness and error removal.

역보행 제어 형태의 궤환 선형화를 이용한 양방향 플래툰 제어 (Bidirectional Platoon Control Using Backstepping-Like Feedback Linearization)

  • 권지욱
    • 제어로봇시스템학회논문지
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    • 제19권5호
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    • pp.410-415
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    • 2013
  • This paper proposes a bidirectional platoon control law using a coupled distance error based on the backstepping-like feedback linearization control method for an interconnected mobile agent system with a string structure. Unlike the previous results where the single agent was controlled using the only own information without other agents, the proposed control law cannot show the only distance error convergence of each agent, but also the string stability of the whole system. Also, the control performances are improved by the proposed control law in spite of low performance of bidirectional control strategy in the previous results. The proposed bidirectional platoon control algorithm is based on the backstepping-like feedback linearization control method. The position errors between each agent and the preceding and the behind agents are coupled by weighted summation. By the proposed control law, the distance error of each agent can converge to zero while the string stability is guaranteed when the coupled errors can converge to zero. To this end, the back-stepping control method is employed. The pseudo velocity input is determined considering the kinematic relationship between agents and the string stability. Then, the actual dynamic control input is determined to make the actual velocity converge to the pseudo velocity input. The stability analysis and the simulation results of the proposed method are included in order to demonstrate the practical application of the proposed algorithm.

Modeling Alignment Experiment Errors for Improved Computer-Aided Alignment

  • Kim, Yunjong;Yang, Ho-Soon;Song, Jae-Bong;Kim, Sug-Whan;Lee, Yun-Woo
    • Journal of the Optical Society of Korea
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    • 제17권6호
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    • pp.525-532
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    • 2013
  • Contrary to the academic interests of other existing studies elsewhere, this study deals with how the alignment algorithms such as sensitivity or Differential Wavefront Sampling (DWS) can be better used under effects from field, compensator positioning and environmental errors unavoidable from the shop-floor alignment work. First, the influences of aforementioned errors to the alignment state estimation was investigated with the algorithms. The environmental error was then found to be the dominant factor influencing the alignment state prediction accuracy. Having understood such relationship between the distorted system wavefront caused by the error sources and the alignment state prediction, we used it for simulated and experimental alignment runs for Infrared Optical System (IROS). The difference between trial alignment runs and experiment was quite close, independent of alignment methods; 6 nm rms for sensitivity method and 13 nm rms for DWS. This demonstrates the practical usefulness and importance of the prior error analysis using the alignment algorithms before the actual alignment runs begin. The error analysis methodology, its application to the actual alignment of IROS and their results are described together with their implications.

인적오류의 세부적 분류와 실증분석에 관한 연구 (A Study on the Detailed Classification and Empirical Analysis of Human Error)

  • 김양규;김칠영;최연철
    • 한국항공운항학회지
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    • 제10권1호
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    • pp.9-20
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    • 2002
  • In aviation, it is important to analyse and classify human error in detail. Because human error has been implicated in 70 or 80% of aviation accidents in literature review. But, there is little detailed classification and research of human error. In this study, Objectives are to establish human error model by classifying types of human error in detail and also to analyse human factors by using the established model. Analysis of the data uses Korea Aviation Incidents Reporting System(GYRO). The resulting from actual analysis, there is a some difference between flight steps for human error occurrence and types of human error are different according to the aviation personnel(pilot, ATC controller).

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적층복합재료 및 샌드위치 판의 적응해석 (Adaptive Analysis of Multilayered Composite and Sandwich Plates)

  • 박진우;김용협
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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    • pp.224-227
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    • 2001
  • Adaptive analysis of multilayered composite and sandwich plates is carried out. The adaptive analysis is based on a finite element error form, which measures the difference between the through-the-thickness distribution of finite element displacement and the actual displacement. The region where the error-measure exceeds the prescribed admitted error value, the finite element mesh locally refined in the thickness direction using the mesh superposition technique. Several numerical tests are conducted to validate the effectiveness of the current approach for adaptive analysis of laminated plates.

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Evaluation of Geometric Error Sources for Terrestrial Laser Scanner

  • Lee, Ji Sang;Hong, Seung Hwan;Park, Il Suk;Cho, Hyoung Sig;Sohn, Hong Gyoo
    • 대한공간정보학회지
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    • 제24권2호
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    • pp.79-87
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    • 2016
  • As 3D geospatial information is demanded, terrestrial laser scanners which can obtain 3D model of objects have been applied in various fields such as Building Information Modeling (BIM), structural analysis, and disaster management. To acquire precise data, performance evaluation of a terrestrial laser scanner must be conducted. While existing 3D surveying equipment like a total station has a standard method for performance evaluation, a terrestrial laser scanner evaluation technique for users is not established. This paper categorizes and analyzes error sources which generally occur in terrestrial laser scanning. In addition to the prior researches about categorizing error sources of terrestrial Laser scanning, this paper evaluates the error sources by the actual field tests for the smooth in-situ applications.The error factors in terrestrial laser scanning are categorized into interior error caused by mechanical errors in a terrestrial laser scanner and exterior errors affected by scanning geometry and target property. Each error sources were evaluated by simulation and actual experiments. The 3D coordinates of observed target can be distortedby the biases in distance and rotation measurement in scanning system. In particular, the exterior factors caused significant geometric errors in observed point cloud. The noise points can be generated by steep incidence angle, mixed-pixel and crosstalk. In using terrestrial laser scanner, elaborate scanning plan and proper post processing are required to obtain valid and accurate 3D spatial information.

기준물을 이용한 NC 공작기계의 오차규명 및 보상제어 (Error Identification and Compensation for NC Machine Tools Using the Reference Artifact)

  • 정성종
    • 한국생산제조학회지
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    • 제9권2호
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    • pp.102-111
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    • 2000
  • Methodology of volumetric error identification and compensation is presented to improve the accuracy of NC machine tools by using a reference artifact and a touch trigger probe. Homogeneous transformation matrix and kinematic chain are used for modeling the geo-metric and thermal errors of a three-axis vertical machining center. The reference artifact is designed and fabricated to identify the model parameters by machine tool metrology. Parameters in the error model are able to be identified and updated by direct measurement of the reference artifact on the machine tool under the actual conditions which include the thermal interactions of error sources. A volumetric error compensation system based on IBM/PC is linked with a FANUC CNC controller to compensate for the identified volumetric error in machining workspace.

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드론 원격정보 격자크기가 실제증발산량 산정에 미치는 영향 (Influence of Scaling in Drone-based Remotely Sensed Information on Actual Evapotranspiration Estimation)

  • 이길하
    • 한국환경과학회지
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    • 제27권2호
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    • pp.135-141
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    • 2018
  • The specification of surface vegetation is essential for simulating actual evapotranspiration of water resources. The availability of land cover maps based on remotely collected data makes the specification of surface vegetation easier. The spatial resolution of hydrologic models rarely matches the spatial scales of the vegetation data needed, and remotely collected vegetation data often are upscaled up to conform to the hydrologic model scale. In this study, the effects of the grid scale of of surface vegetation on the results of actual evapotranspiration were examined. The results show that the coarser resolution causes larger error in relative terms and that a more realistic description of area-averaged vegetation nature and characteristics needs to be considered when calculating actual evapotranspiration.

기준물을 이용한 NC 공작기계의 체적오차 규명 (Volumetric Error Identification for NC Machine Tools Using the Reference Artifact)

  • 김경돈;정성종
    • 대한기계학회논문집A
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    • 제24권12호
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    • pp.2899-2908
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    • 2000
  • Methodology of volumetric error identification is presented to improve the accuracy of NC machine tools by using a reference artifact and a touch trigger probe. Homogeneous transformation matrix and kinematic chain are used for modeling the geometric and thermal errors of a three-axis vertical machining center. The reference artifact is designed and fabricated to identify the model parameters by machine tool metrology. Parameters in the error model are able to be identified and updated by direct measurement of the reference artifact on the machine tool under the actual conditions which include the thermal interactions of error sources. The proposed method can speed up and simplify volumetric error identification processes.

증기발생기 수위제어를 위한 자기동조 퍼지 PID 제어기 개발 (Development of a Self-tuning Fuzzy-PID Controller for Water Level of Steam Generator)

  • 한진욱;이창구;한후석
    • 대한전기학회논문지:전력기술부문A
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    • 제48권10호
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    • pp.1251-1258
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    • 1999
  • The water level control of a steam generator in the unclear power plant is an important process. Most of the water level controllers of the actual plant are PID controllers. But they have limitations in appling for tracking the set point and getting rid of disturbances, so there are some defects to apply in the actual ground even though many research works represented the resolutions to solve it. In this paper, it is suggested that the established simple PID controller in low power has the ability to remove disturbances and trace the set-point, and then possesses the real-time self-tuning function according to the variety of moving peculiarity of a plant. This function realized by making use of fuzzy logic. PID parameters are formulated by a variable ${\alpha}$ and made it fluctuate by a fuzzy inference according to level error and level error change. This mechanism makes application of actual plant effective as well as taking advantage of improving the efficiency of water level controller by way of adding the function of self-tuning instead of replacing PID controller. The computer simulation of this scheme shows the improved performance compare to conventional PID controller.

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