• Title/Summary/Keyword: 기대 오차

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Error Correction of Real-time Situation Recognition using Smart Device (스마트 기기를 이용한 실시간 상황인식의 오차 보정)

  • Kim, Tae Ho;Suh, Dong Hyeok;Yoon, Shin Sook;Ryu, KeunHo
    • Journal of Digital Contents Society
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    • v.19 no.9
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    • pp.1779-1785
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    • 2018
  • In this paper, we propose an error correction method to improve the accuracy of human activity recognition using sensor event data obtained by smart devices such as wearable and smartphone. In the context awareness through the smart device, errors inevitably occur in sensing the necessary context information due to the characteristics of the device, which degrades the prediction performance. In order to solve this problem, we apply Kalman filter's error correction algorithm to compensate the signal values obtained from 3-axis acceleration sensor of smart device. As a result, it was possible to effectively eliminate the error generated in the process of the data which is detected and reported by the 3-axis acceleration sensor constituting the time series data through the Kalman filter. It is expected that this research will improve the performance of the real-time context-aware system to be developed in the future.

A study on the Accuracy Analysis of Quadrilateral Nets by Analytical Methods (해석기법에 따른 사변형망의 정확도해석에 관한 연구)

  • 강준묵;이진덕;한승희;이용창
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.6 no.1
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    • pp.3-12
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    • 1988
  • The objective of this paper is to study the characteristics of combination method to correct both angle and distance errors simultaneously based on the least square adjustment methods. Changing the standard errors of distance and angle, the simulation errors of triangultion, trilateration, and combination result in some 39.8%, 33.9%, and 26.3% respectively. As the above, combination method shows more consistent accuracy than other methods. When considering the weight factor about error elements with independence, the diminishing rate of simulated average standard error represents a various change in each method. But considering them simultaneously, it shows a remarkable rate of diminishing 75.5%, 74.1%, and 69.2% in each method. And also, by growing the weight factor, accuracy of triangulation method is growing, whereas that of trilateration is diminishing. Therefore, determining the reasonable weight factors of distance and angle errors simultaneously in the analytical combination method, this method is expected to be one of more accurate and more effective methods for determining horizontal positions on the earth.

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Development and Positioning Accuracy Assessment of Precise Point Positioning Algorithms based on GPS Code-Pseudorange Measurements (GPS 코드의사거리 기반 정밀단독측위(PPP) 알고리즘 개발 및 측위 정확도 평가)

  • Park, Kwan Dong;Kim, Ji Hye;Won, Ji Hye;Kim, Du Sik
    • Journal of Korean Society for Geospatial Information Science
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    • v.22 no.1
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    • pp.47-54
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    • 2014
  • Precise Point Positioning (PPP) algorithms using GPS code pseudo-range measurements were developed and their accuracy was validated for the purpose of implementing them on a portable device. The group delay, relativistic effect, and satellite-antenna phase center offset models were applied as fundamental corrections for PPP. GPS satellite orbit and clock offsets were taken from the International GNSS Service official products which were interpolated using the best available algorithms. Tropospheric and ionospheric delays were obtained by applying mapping functions to the outputs from scientific GPS data processing software and Global Ionosphere Maps, respectively. When the developed algorithms were tested for four days of data, the horizontal and vertical positioning accuracies were 0.8-1.6 and 1.6-2.2 meters, respectively. This level of performance is comparable to that of Differential GPS, and further improvements and fine-tuning of this suite of PPP algorithms and its implementation at a portable device should be utilized in a variety of surveying and Location-Based Service applications.

Research of Satellite Autonomous Navigation Using Star Sensor Algorithm (별 추적기 알고리즘을 활용한 위성 자율항법 연구)

  • Hyunseung Kim;Chul Hyun;Hojin Lee;Donggeon Kim
    • Journal of Space Technology and Applications
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    • v.4 no.3
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    • pp.232-243
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    • 2024
  • In order to perform various missions in space, including planetary exploration, estimating the position of a satellite in orbit is a very important factor because it is directly related to the success rate of mission performance. As a study for autonomous satellite navigation, this study estimated the satellite's attitude and real time orbital position using a star sensor algorithm with two star trackers and earth sensor. To implement the star sensor algorithm, a simulator was constructed and the position error of the satellite estimated through the technique presented in the paper was analyzed. Due to lens distortion and errors in the center point finding algorithm, the average attitude estimation error was at the level of 2.6 rad in the roll direction. And the position error was confirmed by attitude error, so average error in altitude direction was 516 m. It is expected that the proposed satellite attitude and position estimation technique will contribute to analyzing star sensor performance and improving position estimation accuracy.

(Theoretical Analysis and Performance Prediction for PSN Filter Tracking) (PSN 픽터의 해석 및 추적성능 예측)

  • Jeong, Yeong-Heon;Kim, Dong-Hyeon;Hong, Sun-Mok
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.39 no.2
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    • pp.166-175
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    • 2002
  • In this paper. we predict tracking performance of the probabilistic strongest neighbor filter (PSNF). The PSNF is known to be consistent and superior to the probabilistic data association filter (PDAF) in both performance and computation. The PSNF takes into account the probability that the measurement with the strongest intensity in the neighborhood of the predicted target measurement location is not target-originated. The tracking performance of the PSNF is quantified in terms of its estimation error covariance matrix. The estimation error covariance matrix is approximately evaluated by using the hybrid conditional average approach (HYCA). We performed numerical experiments to show the validity of our performance prediction.

Accuracy Evaluation of Boundary corner point using VRS GPS (VRS GPS을 이용한 필계점의 정확도 평가)

  • Jang, Sang-Kyu;Kim, Jin-Soo;Jeong, Gong-Uhn
    • Journal of Korean Society for Geospatial Information Science
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    • v.17 no.1
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    • pp.37-42
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    • 2009
  • The accuracy of RTK GPS is limited by the distance dependent errors from orbit, ionosphere and troposphere, as the distance between the rover and the base station increases in the Real Time Kinematic surveying. To solve this problem, VRS system has installed. This study would estimated the accuracy of cadastral detail surveying, which is used on the VRS RTK instead of Total Station and RTK GPS demand for various equipments and time. As a result of study, the positioning accuracy of the VRS RTK and RTK GPS surveying make no greate difference, as RMSE of VRS RTK surveying is 0.144m and that of RTK GPS surveying is 0.146m and the new method would be more efficient.

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A Study on Three-dimensional Coordinates Analysis Using Mirror Images (거울영상을 이용한 3차원 좌표해석에 관한 연구)

  • 유복모;이현직;정영동;오창수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.4 no.1
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    • pp.25-36
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    • 1986
  • Minimum three pairs of model are necessary to determine absolute coordinates of three-dimensional objects. This paper researches the method of analyzing three-dimensional coordinates of all sides of objects by photographing a pair of stereo model through the medium of mirror. An objective lies in improving the accuracy and the efficiency of mirror images method by introducing an error correction function for distortion of the mirror. Projected-onto-mirror points are transformed on the object plane through mirror plane equation. As the result, X-coordinates error is the largest and Y, Z-coordinates error represents about 1mm. Also, accuracy can be improved by introducing correction function for left and right mirror and correcting the distortion of mirror.

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Fabrication and Characteristics of 30 MN Strain Gage Type Force Sensor (30 MN 스트레인 게이지 방식 힘 센서의 제작 및 특성)

  • Kang, D.I.;Song, H.K.;Lee, J.T.
    • Journal of Sensor Science and Technology
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    • v.3 no.2
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    • pp.24-32
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    • 1994
  • A force sensor of 30 MN capacity using build-up technique in which three load cells of 10 MN capacity are arranged in parallel was fabricated. A column spring element was adopted as a shape of a strain gage type load cell. Temperature compensation circuits were used to reduce the error of a load cell. It was estimated that the total error of the fabricated force sensor is less than 0.1 %. The force sensor may be used to calibrate or test material testing machines above 4.5 MN capacity in industries.

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A study of modeling the ultrasonic transducer equivalent circuit (초음파 진동자 등가회로의 모델링에 관한 연구)

  • Kim, Kun;Na, Hee-Chang;Cha, Ll-Whan
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1984.12a
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    • pp.15-19
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    • 1984
  • 본 연구는 piezo-electric transducer 등가회로의 모델링에 관한 연구로서 진동시에 발생하는 공진주파수와 harmonics까지 고려한 등가모델을 제시하였다. 실험결과 공진주파수만을 고려한 모델의 경우 harmonics를 제외한 부분에서 평균 6.5%의 오차가 발생하였으며 harmonics까지 고려한 모델에서는 평균오차가 5.3%로서 그 차이점을 줄일 수 있어 실제등가회로에 접근함을 알 수 있었다. 본 연구의 결과는 음향변환기의 전기적 특성을 파악함으로써 전기-음향 상사관계의 제반응용에 이용될 것이 기대된다.

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Prediction Value Estimation in Transformed GARCH Models (변환된 GARCH모형에서의 예측값 추정)

  • Park, Ju-Yeon;Yeo, In-Kwon
    • The Korean Journal of Applied Statistics
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    • v.22 no.5
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    • pp.971-979
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    • 2009
  • In this paper, we introduce the method that reduces the bias when the transformation and back-transformation approach is applied in GARCH models. A parametric bootstrap is employed to compute the conditional expectation which is the prediction value to minimize mean square errors in the original scale. Through the analyese of returns of KOSPI and KOSDAQ, we verified that the proposed method provides a bias-reduced estimation for the prediction value.