• Title/Summary/Keyword: accuracy assessment

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Probabilistic bearing capacity assessment for cross-bracings with semi-rigid connections in transmission towers

  • Zhengqi Tang;Tao Wang;Zhengliang Li
    • Structural Engineering and Mechanics
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    • v.89 no.3
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    • pp.309-321
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    • 2024
  • In this paper, the effect of semi-rigid connections on the stability bearing capacity of cross-bracings in steel tubular transmission towers is investigated. Herein, a prediction method based on the hybrid model which is a combination of particle swarm optimization (PSO) and backpropagation neural network (BPNN) is proposed to accurately predict the stability bearing capacity of cross-bracings with semi-rigid connections and to efficiently conduct its probabilistic assessment. Firstly, the establishment of the finite element (FE) model of cross-bracings with semi-rigid connections is developed on the basis of the development of the mechanical model. Then, a dataset of 7425 samples generated by the FE model is used to train and test the PSO-BPNN model, and the accuracy of the proposed method is evaluated. Finally, the probabilistic assessment for the stability bearing capacity of cross-bracings with semi-rigid connections is conducted based on the proposed method and the Monte Carlo simulation, in which the geometric and material properties including the outer diameter and thickness of cross-sections and the yield strength of steel are considered as random variables. The results indicate that the proposed method based on the PSO-BPNN model has high accuracy in predicting the stability bearing capacity of cross-bracings with semi-rigid connections. Meanwhile, the semi-rigid connections could enhance the stability bearing capacity of cross-bracings and the reliability of cross-bracings would significantly increase after considering semi-rigid connections.

Precision Assessment of Near Real Time Precise Orbit Determination for Low Earth Orbiter

  • Choi, Jong-Yeoun;Lee, Sang-Jeong
    • Journal of Astronomy and Space Sciences
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    • v.28 no.1
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    • pp.55-62
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    • 2011
  • The precise orbit determination (POD) of low earth orbiter (LEO) has complied with its required positioning accuracy by the double-differencing of observations between International GNSS Service (IGS) and LEO to eliminate the common clock error of the global positioning system (GPS) satellites and receiver. Using this method, we also have achieved the 1 m positioning accuracy of Korea Multi-Purpose Satellite (KOMPSAT)-2. However double-differencing POD has huge load of processing the global network of lots of ground stations because LEO turns around the Earth with rapid velocity. And both the centimeter accuracy and the near real time (NRT) processing have been needed in the LEO POD applications--atmospheric sounding or urgent image processing--as well as the surveying. An alternative to differential GPS for high accuracy NRT POD is precise point positioning (PPP) to use measurements from one satellite receiver only, to replace the broadcast navigation message with precise post processed values from IGS, and to have phase measurements of dual frequency GPS receiver. PPP can obtain positioning accuracy comparable to that of differential positioning. KOMPSAT-5 has a precise dual frequency GPS flight receiver (integrated GPS and occultation receiver, IGOR) to satisfy the accuracy requirements of 20 cm positioning accuracy for highly precise synthetic aperture radar image processing and to collect GPS radio occultation measurements for atmospheric sounding. In this paper we obtained about 3-5 cm positioning accuracies using the real GPS data of the Gravity Recover and Climate Experiment (GRACE) satellites loaded the Blackjack receiver, a predecessor of IGOR. And it is important to reduce the latency of orbit determination processing in the NRT POD. This latency is determined as the volume of GPS measurements. Thus changing the sampling intervals, we show their latency to able to reduce without the precision degradation as the assessment of their precision.

A Study on the Map Accuracy Assessment of Positioning Data Using Statistical Approach Analysis (오차분석을 이용한 지도 위치정확도 평가기법에 관한 연구)

  • Cho, Bong-Whan;Lee, Yong-Woong;Choi, Sun-Yong
    • Journal of Korean Society for Geospatial Information Science
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    • v.5 no.1 s.9
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    • pp.71-80
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    • 1997
  • This paper suggests a Map Accuracy Standards by analyzing U.S. National Map Accuracy Standards, by considering korean terrain feature and statistical error theory for paper and digital maps on the scale of 1:50,000. Map accuracy standards require horizontal accuracy to be reported as a circular error with 90% confidence level through Linear Error Probable(LEP) theory and Circular Error Probable(CEP) theory. In order to verify the proposed methodology for positioning accuracy testing, several kinds of test point were selected and tested. These test points were extracted at the centers of roads and bridges, the comers of the independent building, the edges of geographical botany, and the tops of mountains. The positioning accuracy assessment was peformed by comparing the positions of test points in digital maps generated three different sources with those acquired by high accurate GPS surveying. The digital maps were produced from aerial photographs and SPOT satellite image using analytical plotter and 1:50,000 paper map.

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The study for the applications of the measurement system assessment in statistical process control (통계적 공정관리 추진시 측정시스템 평가의 실시방법에 관한 연구)

  • 민철희;백재욱
    • The Korean Journal of Applied Statistics
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    • v.11 no.1
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    • pp.13-28
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    • 1998
  • Corrent measurement system assessment is crucial in helping improve process or quality. In this article, we would like to apply several methods of measurement system assessment in statistical process control. Specifically, focus is on accuracy, precision (both repeatability and reproducibility included), and stability of the measurement process.

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The Study of Promotion for Fire Assessment System (화재영향 평가 제도화 추진에 관한 연구)

  • 김광일;윤명오
    • Fire Science and Engineering
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    • v.10 no.1
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    • pp.25-43
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    • 1996
  • This paper has been studied about promotion system for fire assessment. Mainly system carried out for BCJ (Building Center of Japan) and JFSC (Japan Fire Safety Center) fire risk assessment system. Much of the work of fire science and fire protection engineering is now explicitly designed to fill gaps or improve accuracy or flexibility In some comprehensive fire hazard or fire risk models.

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Development of New Photogrammetric Software for High Quality Geo-Products and Its Performance Assessment

  • Jeong, Jae-Hoon;Lee, Tae-Yoon;Rhee, Soo-Ahm;Kim, Hyeon;Kim, Tae-Jung
    • Korean Journal of Remote Sensing
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    • v.28 no.3
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    • pp.319-327
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    • 2012
  • In this paper, we introduce a newly developed photogrammetric software for automatic generation of high quality geo-products and its performance assessment carried out using various satellite images. Our newly developed software provides the latest techniques of an optimized sensor modelling, ortho-image generation and automated Digital Elevation Model (DEM) generation for diverse remote sensing images. In particular, images from dual- and multi-sensor images can be integrated for 3D mapping. This can be a novel innovation toward a wider applicability of remote sensing data, since 3D mapping has been limited within only single-sensor so far. We used Kompsat-2, Ikonos, QuickBird, Spot-5 high resolution satellite images to test an accuracy of 3D points and ortho-image generated by the software. Outputs were assessed by comparing reliable reference data. From various sensor combinations 3D mapping were implemented and their accuracy was evaluated using independent check points. Model accuracy of 1~2 pixels or better was achieved regardless of sensor combination type. The high resolution ortho-image results are consistent with the reference map on a scale of 1:5,000 after being rectified by the software and an accuracy of 1~2 pixels could be achieved through quantitative assessment. The developed software offers efficient critical geo-processing modules of various remote sensing images and it is expected that the software can be widely used to meet the demand on the high-quality geo products.

Validation on the Application of Bluetooth-based Inertial Measurement Unit for Wireless Gait Analysis (무선 보행 분석을 위한 블루투스 기반 관성 측정 장치의 활용 타당성 분석)

  • Hwang, Soree;Sung, Joohwan;Park, Heesu;Han, Sungmin;Yoon, Inchan
    • Journal of Biomedical Engineering Research
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    • v.41 no.3
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    • pp.121-127
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    • 2020
  • The purpose of this paper is to review the validation on the application of low frequency IMU(Inertial Measurement Unit) sensors by replacing high frequency motion analysis systems. Using an infrared-based 3D motion analysis system and IMU sensors (22 Hz) simultaneously, the gait cycle and knee flexion angle were measured. And the accuracy of each gait parameter was compared according to the statistical analysis method. The Bland-Altman plot analysis method was used to verify whether proper accuracy can be obtained when extracting gait parameters with low frequency sensors. As a result of the study, the use of the new gait assessment system was able to identify adequate accuracy in the measurement of cadence and stance phase. In addition, if the number of gait cycles is increased and the results of body anthropometric measurements are reflected in the gait analysis algorithm, is expected to improve accuracy in step length, walking speed, and range of motion measurements. The suggested gait assessment system is expected to make gait analysis more convenient. Furthermore, it will provide patients more accurate assessment and customized rehabilitation program through the quantitative data driven results.

A Quantitative Evaluation on Developmental Organization of Technical Proposals (기술제안서의 개발조직 부문에 관한 정량적 평가)

  • Choo, Kyung-Kyun;Kwon, Young-Kap;Rhew, Sung-Yul
    • Journal of Information Technology Services
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    • v.3 no.1
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    • pp.21-41
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    • 2004
  • The technical proposal suggested and published by MIC(Ministry of Information and Communication, henceforth MIC) contains too general assessment elements, which causes qualitative and subjective assessment of technical proposals. Thus, in terms of the technical proposal assessment. It lacks In fairness, validity and accuracy. Furthermore, it has a great deal of difficulty in assessment caused by the inconsistency between proposal planning and assessment methods. Also, each company has different writing format, so it is impossible to make use of its maneuvering data for the assessment. To overcome these weaknesses, our research focused on a quantitative evaluation on development organization, which is a part of organizational and administrative part of the technical proposal suggested and published by MIC. In this research, we divided development organization for the technical proposal into organization, teams, and team members, and then studied addition, deletion and merging for the assessment criteria. For the related study, we chose especially CMM(Capability Maturity Model) from a lot of international and national references, which is a model measuring the maturity of organization, and then we focused on Small-CMM which is available in the small-sized organization. We also suggested input form, description method, assessment elements for the quantitative assessment in the chosen developmental organization, and finally we proposed standard referencing criteria for the assessment. Our study concludes that our assessment method are valid and available in comparison with the previous Delphi method through a validity evaluation test.

A Study on the Risk Assessment for Urban Railway Systems Using an Adaptive Neuro-Fuzzy Inference System(ANFIS) (적응형 뉴로-퍼지(ANFIS)를 이용한 도시철도 시스템 위험도 평가 연구)

  • Tak, Kil Hun;Koo, Jeong Seo
    • Journal of the Korean Society of Safety
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    • v.37 no.1
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    • pp.78-87
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    • 2022
  • In the risk assessment of urban railway systems, a hazard log is created by identifying hazards from accident and failure data. Then, based on a risk matrix, evaluators analyze the frequency and severity of the occurrence of the hazards, conduct the risk assessment, and then establish safety measures for the risk factors prior to risk control. However, because subjective judgments based on the evaluators' experiences affect the risk assessment results, a more objective and automated risk assessment system must be established. In this study, we propose a risk assessment model in which an adaptive neuro-fuzzy inference system (ANFIS), which is combined in artificial neural networks (ANN) and fuzzy inference system (FIS), is applied to the risk assessment of urban railway systems. The newly proposed model is more objective and automated, alleviating the limitations of risk assessments that use a risk matrix. In addition, the reliability of the model was verified by comparing the risk assessment results and risk control priorities between the newly proposed ANFIS-based risk assessment model and the risk assessment using a risk matrix. Results of the comparison indicate that a high level of accuracy was demonstrated in the risk assessment results of the proposed model, and uncertainty and subjectivity were mitigated in the risk control priority.

A Study on the Accuracy Assessment of Digital Map (수치지도의 정확도 검정에 관한 연구)

  • 김병국;최정민;김은모
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.16 no.2
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    • pp.319-326
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    • 1998
  • In this study, it was tried to experimentally judge the positional accuracy of digital maps, which are being constructed with a vast of investment and national endeavor. Using GPS and Total Station, field surveying to assess the positional accuracy of 1:5,000 digital maps was conducted. According to these results, the digital maps were compared to the real field test. And in order to check the positional accuracy standard of digital maps, theoretical positional accuracy of 1:5,000 digital maps are compared with that from field test data to propose research activities for hereafter positional accuracy standard of digital map.

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