• 제목/요약/키워드: actual error

검색결과 1,365건 처리시간 0.026초

Performance Analysis of Low-Order Surface Methods for Compact Network RTK: Case Study

  • Song, Junesol;Park, Byungwoon;Kee, Changdon
    • Journal of Positioning, Navigation, and Timing
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    • 제4권1호
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    • pp.33-41
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    • 2015
  • Compact Network Real-Time Kinematic (RTK) is a method that combines compact RTK and network RTK, and it can effectively reduce the time and spatial de-correlation errors. A network RTK user receives multiple correction information generated from reference stations that constitute a network, calculates correction information that is appropriate for one's own position through a proper combination method, and uses the information for the estimation of the position. This combination method is classified depending on the method for modeling the GPS error elements included in correction information, and the user position accuracy is affected by the accuracy of this modeling. Among the GPS error elements included in correction information, tropospheric delay is generally eliminated using a tropospheric model, and a combination method is then applied. In the case of a tropospheric model, the estimation accuracy varies depending on the meteorological condition, and thus eliminating the tropospheric delay of correction information using a tropospheric model is limited to a certain extent. In this study, correction information modeling accuracy performances were compared focusing on the Low-Order Surface Model (LSM), which models the GPS error elements included in correction information using a low-order surface, and a modified LSM method that considers tropospheric delay characteristics depending on altitude. Both of the two methods model GPS error elements in relation to altitude, but the second method reflects the characteristics of actual tropospheric delay depending on altitude. In this study, the final residual errors of user measurements were compared and analyzed using the correction information generated by the various methods mentioned above. For the performance comparison and analysis, various GPS actual measurement data were collected. The results indicated that the modified LSM method that considers actual tropospheric characteristics showed improved performance in terms of user measurement residual error and position domain residual error.

A Study on Circular Contour Machining Error

  • Namkoong, Chaikwan
    • 한국공작기계학회논문집
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    • 제11권5호
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    • pp.100-105
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    • 2002
  • The comprehensive system analysis for contour milling operation and its error has performed in this study. The obtained experimental results were from the practical points of view. In down-milling operation the contour error curve illustrates bigger thean actual workpiece radius. The contour error increased when the cutter loads increased. Through the procedural evaluation, it could ascertain the characteristics of generation mechanics in circular contour machining error, and the weight of each factors.

SE프로세스를 적용한 UTM 환경의 항법 오차 산출 필요성 검토 (SA Review on Necessity to Calculate Navigation Errors in UTM Environments with SE Process)

  • 구성관;안효정;김도현
    • 한국항공운항학회지
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    • 제28권4호
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    • pp.47-54
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    • 2020
  • This study carries out a basic study of ways to calculate navigation errors for aircraft operating in the unmanned aerial system traffic management(UTM). Recently, research by UTM has been carried out both at home and abroad, along with the initial study of system definitions at the basic stage, operational techniques of the aircraft, and the practicality of the concept of necessary operations at the actual operational stage. This study presented after a review the factors that should be considered for the calculation of navigation errors among the factors that examine whether the actual low altitude aircraft can operate properly within UTM during its actual operation and the need to apply them in practice.

고속도로 건설현장의 인적오류 예방을 위한 실무자용 도구 개발 (Hands-on Tools to Prevent Human Errors in Highway Construction)

  • 김정룡;윤상영;조영진
    • 대한인간공학회지
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    • 제30권1호
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    • pp.19-28
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    • 2011
  • Objective: The aim of this study is to reclassify human errors and to develop hands-on tools to apply the new classification for preventing human error accidents in highway construction site. Background: The main cause of accidents in highway construction was reported as the carelessness of workers. However, such diagnosis could not help us operationally prevent accidents in real workplace. Method: The accidents in highway construction were reanalyzed and the causes of human error were reclassified in order to educate and improve the awareness of human error in highway construction. Field survey and interview with safety managers and workers were conducted to find the causal relationship between the actual accidents and the human errors. Results: The most frequently observed human errors in highway construction were classified into six categories such as mis-perception, distraction, memory fail, slip, cognition error and mis-judgment. In order to provide hands-on tools to increase the awareness of human error in construction field, the human error checklist and card sorting diary were developed. Especially, the card sorting diary was designed to increase the ability in human error inspection of safety manager at construction site. Moreover, posters were developed based on actual accident cases. Conclusion: We suggested that the improved awareness and analytical report on checklist, card sorting diary and posters for construction field could collectively prevent the accident. Application: The classification of human error, hands-on tools and posters can be directly applicable on highway construction site. This analytical and collective approach preventing human error-related accident could be extended to other construction workplaces.

단안 카메라를 이용한 LKAS 시험평가 방법에 관한 연구 (A Study on the Test Evaluation Method of LKAS Using a Monocular Camera)

  • 배건환;이선봉
    • 자동차안전학회지
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    • 제12권3호
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    • pp.34-42
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    • 2020
  • ADAS (Advanced Driver Assistance Systems) uses sensors such as camera, radar, lidar and GPS (Global Positioning System). Among these sensors, the camera has many advantages compared with other sensors. The reason is that it is cheap, easy to use and can identify objects. In this paper, therefore, a theoretical formula was proposed to obtain the distance from the vehicle's front wheel to the lane using a monocular camera. And the validity of the theoretical formula was verified through the actual vehicle test. The results of the actual vehicle test in scenario 4 resulted in a maximum error of 0.21 m. The reason is that it is difficult to detect the lane in the curved road, and it is judged that errors occurred due to the occurrence of significant yaw rates. The maximum error occurred in curve road condition, but the error decreased after lane return. Therefore, the proposed theoretical formula makes it possible to assess the safety of the LKA system.

DC 모터 시스템을 위한 짧은 샘플링 시간을 갖는 이산슬라이딩 모드의 최종 수렴범위 (The Ultimate Bound of Discrete Sliding Mode Control System with Short Sampling Period for DC Motor System)

  • 박흠용;조영훈;박강박
    • 제어로봇시스템학회논문지
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    • 제16권3호
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    • pp.245-248
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    • 2010
  • Almost all of control schemes proposed so far have been designed in the continuous-time domain theoretically. Actual systems, however, have been implemented in the discrete-time domain since Micro Control Unit(MCU) and/or microprocessors have been used for the controllers. Thus, the overall system turned to be a sampled-data system, and generally speaking, the ultimate error cannot converge to zero in the actual system even though the proposed control algorithm showed the asymptotic stability in the continuous-time domain. In this paper, therefore, the ultimate error bound of a sampled data system with a short sampling period has been investigated. The ultimate error is shown to be related in the sampling period.

Analysis of Characteristics of All Solid-State Batteries Using Linear Regression Models

  • Kyo-Chan Lee;Sang-Hyun Lee
    • International journal of advanced smart convergence
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    • 제13권1호
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    • pp.206-211
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    • 2024
  • This study used a total of 205,565 datasets of 'voltage', 'current', '℃', and 'time(s)' to systematically analyze the properties and performance of solid electrolytes. As a method for characterizing solid electrolytes, a linear regression model, one of the machine learning models, is used to visualize the relationship between 'voltage' and 'current' and calculate the regression coefficient, mean squared error (MSE), and coefficient of determination (R^2). The regression coefficient between 'Voltage' and 'Current' in the results of the linear regression model is about 1.89, indicating that 'Voltage' has a positive effect on 'Current', and it is expected that the current will increase by about 1.89 times as the voltage increases. MSE found that the mean squared error between the model's predicted and actual values was about 0.3, with smaller values closer to the model's predictions to the actual values. The coefficient of determination (R^2) is about 0.25, which can be interpreted as explaining 25% of the data.

산업용 로봇 매니퓰레이터의 다변수 제어기 설계 (A Design on Multivariable Controller for Industrial Robot Manipulators)

  • 한상완;홍석교
    • 제어로봇시스템학회논문지
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    • 제4권5호
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    • pp.636-643
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    • 1998
  • This paper is presents multivariable control scheme for industrial robot manipulators. The control scheme consists of two loops. The modeling error between linearized robot model and actual robot model is compensated in error compensation loop. The PID control loop is designed for pole assignment to stability of robot system and utilized for trajectory tracking. Alternatively computer simulation results are given for illustration purpose of suggested controller.

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국공유지 실태조사 활용을 위한 UAV 영상의 정확도 및 경제성 평가 (Accuracy and Economic Evaluation for Utilization of National/Public Land Actual Condition Survey Using UAV Images)

  • 이상찬;김준현;엄정섭
    • 한국측량학회지
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    • 제35권3호
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    • pp.175-186
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    • 2017
  • 본 연구에서는 UAV를 이용한 국공유지 실태조사 필지의 효율성과 정확성을 평가하기 위해 지적현황측량 검사점의 정확성과 경제적 비용측면에서 제시하였다. 분석결과를 요약하면 다음과 같다. 첫째, 정사영상의 위치오차는 평균적으로 X오차 0.033m, Y오차 0.023m로 나타나 평면거리 연결교차로 계산하면 RMSE 평균은 0.046m로 나타났다. 둘째, 정사영상과 VRS-GNSS 성과비교에서는 UAV 정사영상 이미지 검사점의 최대 RMSE는 0.076m이고 최소 RMSE는 0.042m로 나타났다. 세째, 모든 검사점이 현행 지적측량규정에 명시된 1/1,200의 축척에 해당하는 0.360m 이내의 오차범위를 만족하였다. 끝으로 국공유지 실태조사를 위한 경제성 평가에서는, UAV 활용방법이 지적현황측량 방법보다 26,497,436원이 더 적게 들어가는 것으로 나타났다. 따라서, 본 연구결과 국공유지 실태조사에서 UAV를 활용하는 방법은 정확도 측면에서도 법적 기준을 충족하며, 경제성 측면 역시 지자체의 예산을 더욱 줄일 수 있는 방법으로 나타났다.

고속 고정밀의 자유곡선 가공을 위한 다축 윤곽오차 제어 (A Multi-Axis Contour Error Controller for High-Speed/High-Precision Machining of Free form Curves)

  • 이명훈;최정희;이영문;양승한
    • 한국정밀공학회지
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    • 제21권4호
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    • pp.64-71
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    • 2004
  • The growing need for higher precision and productivity in manufacturing industry has lead to an increased interest in computer numerical control (CNC) systems. It is well known fact that the cross-coupling controller (CCC) is an effective method for contouring applications. In this paper, a multi-axis contour error controller (CEC) based on a contour error vector using parametric curve interpolator is introduced. The contour error vector is a vector from the actual tool position to the nearest point on the desired path. The contour error vector is the closest error model to the contour error. The simulation results show that the CEC is more accurate than the conventional CCC for a biaxial motion system. In addition, the experimental results on 3-axis motion system show that the CEC is simply applied to 3-axis motions and contouring accuracy is significantly improved.