• 제목, 요약, 키워드: accuracy-study

검색결과 12,693건 처리시간 0.067초

Performance Analysis of Ranging Techniques for the KPLO Mission

  • Park, Sungjoon;Moon, Sangman
    • Journal of Astronomy and Space Sciences
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    • v.35 no.1
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    • pp.39-46
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    • 2018
  • In this study, the performance of ranging techniques for the Korea Pathfinder Lunar Orbiter (KPLO) space communication system is investigated. KPLO is the first lunar mission of Korea, and pseudo-noise (PN) ranging will be used to support the mission along with sequential ranging. We compared the performance of both ranging techniques using the criteria of accuracy, acquisition probability, and measurement time. First, we investigated the end-to-end accuracy error of a ranging technique incorporating all sources of errors such as from ground stations and the spacecraft communication system. This study demonstrates that increasing the clock frequency of the ranging system is not required when the dominant factor of accuracy error is independent of the thermal noise of the ranging technique being used in the system. Based on the understanding of ranging accuracy, the measurement time of PN and sequential ranging are further investigated and compared, while both techniques satisfied the accuracy and acquisition requirements. We demonstrated that PN ranging performed better than sequential ranging in the signal-to-noise ratio (SNR) regime where KPLO will be operating, and we found that the T2B (weighted-voting balanced Tausworthe, voting v = 2) code is the best choice among the PN codes available for the KPLO mission.

Effects of pelvic stability on instep shooting speed and accuracy in junior soccer players

  • Sung, Ha-Rim;Shin, Won-Seob
    • Physical Therapy Rehabilitation Science
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    • v.7 no.2
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    • pp.78-82
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    • 2018
  • Objective: The purpose of this study was to determine the effect of wearing a pelvic compression belt on ball speed and accuracy in instep shoots of youth soccer players. Design: Randomized cross-over design. Methods: We included 20 male junior soccer players with experience of more than 5 years. Participants were randomly assigned to two conditions: application of a pelvic compression belt and instep shooting or no application. Instep shooting was performed three times at a distance of 20 meters from the position of the goal post, and the ball speed was measured using a speed gun at a position 5 meters behind the goal post. The shooting accuracy was measured based on a 5-point scale. The shooting accuracy was measured by scoring 5 points at 2.44 meters in the middle of the goal area of area A, 3 points at 2.44 meters in the goal area of area B, and 0 in the case of shooting outside the goal area C. Results: After applying a pelvic compression belt, the mean speed of the ball was significantly increased (p<0.05). The maximum speed of the ball was significantly increased (p<0.05). The accuracy of the ball was significantly increased (p<0.05). Conclusions: Through this study, we expect that the use of the pelvic compression belt can be applied as a training method to improve the shooting ability of soccer players. Clinically, pelvic compression belts are expected to help rehabilitation soccer players to improve their shooting accuracy.

Comparison the Mapping Accuracy of Construction Sites Using UAVs with Low-Cost Cameras

  • Jeong, Hohyun;Ahn, Hoyong;Shin, Dongyoon;Choi, Chuluong
    • 대한원격탐사학회지
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    • v.35 no.1
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    • pp.1-13
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    • 2019
  • The advent of a fourth industrial revolution, built on advances in digital technology, has coincided with studies using various unmanned aerial vehicles (UAVs) being performed worldwide. However, the accuracy of different sensors and their suitability for particular research studies are factors that need to be carefully evaluated. In this study, we evaluated UAV photogrammetry using smart technology. To assess the performance of digital photogrammetry, the accuracy of common procedures for generating orthomosaic images and digital surface models (DSMs) using terrestrial laser scanning (TLS) techniques was measured. Two different type of non-surveying camera(Smartphone camera, fisheye camera) were attached to UAV platform. For fisheye camera, lens distortion was corrected by considering characteristics of lens. Accuracy of orthoimage and DSM generated were comparatively analyzed using aerial and TLS data. Accuracy comparison analysis proceeded as follows. First, we used Ortho mosaic image to compare the check point with a certain area. In addition, vertical errors of camera DSM were compared and analyzed based on TLS. In this study, we propose and evaluate the feasibility of UAV photogrammetry which can acquire 3 - D spatial information at low cost in a construction site.

Modification of the fast fourier transform-based method by signal mirroring for accuracy quantification of thermal-hydraulic system code

  • Ha, Tae Wook;Jeong, Jae Jun;Choi, Ki Yong
    • Nuclear Engineering and Technology
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    • v.49 no.5
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    • pp.1100-1108
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    • 2017
  • A thermal-hydraulic system code is an essential tool for the design and safety analysis of a nuclear power plant, and its accuracy quantification is very important for the code assessment and applications. The fast Fourier transform-based method (FFTBM) by signal mirroring (FFTBM-SM) has been used to quantify the accuracy of a system code by using a comparison of the experimental data and the calculated results. The method is an improved version of the FFTBM, and it is known that the FFTBM-SM judges the code accuracy in a more consistent and unbiased way. However, in some applications, unrealistic results have been obtained. In this study, it was found that accuracy quantification by FFTBM-SM is dependent on the frequency spectrum of the fast Fourier transform of experimental and error signals. The primary objective of this study is to reduce the frequency dependency of FFTBM-SM evaluation. For this, it was proposed to reduce the cut off frequency, which was introduced to cut off spurious contributions, in FFTBM-SM. A method to determine an appropriate cut off frequency was also proposed. The FFTBM-SM with the modified cut off frequency showed a significant improvement of the accuracy quantification.

수종 고무 교합인기 재료의 정확성에 관한 연구 (ACCURACY OF FOUR ELASTOMERIC INTEROCCLUSAL RECORDING MATERIALS)

  • 배정식
    • 대한치과보철학회지
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    • v.36 no.2
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    • pp.355-365
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    • 1998
  • The purpose of this study is to evaluate the accuracy of four elastomeric interocclusal recording materials and the weight change according to different storage period (24 hours, 48hours, 7days) and different conditions (dry, wet). The techniques for establishing the intercuspal position were centic occlusion interocclusal record with four elastomeric interocclusal recording materials (Ramitec, Stat-BR, Blu-Mousse, Regisil) (experimental groups) and location of the cast in a position of maximum in-terdigitation using tactile and visual method(control group). To evaluate the accuracy of four elastomeric interocclusal recording materials, the quality of contacts between the mounted casts was compared with the results of an occlusal examination of the same subjects. The results were as follows : 1. The most accurate method of articulating study casts at the intercuspal position was by hand articulation and no significant differences in accuracy were observerd among the experimental groups. 2. In case of interocclusal records storaged in dry sealed plastic box, no significant differences in accuracy were observed among the experimental groups. 3. In case of interocclusal records storaged in water, there was significant inaccuracy in Ramitec group. 4. The biggest weight change was observed in Ramitec group in all storage conditions

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3D체형측정기와 수동측정 방법간의 사상체질별 ${\cdot}$ 성별 진단정확률 비교연구 (Diagnosis Accuracy Rate Comparative Study of Each Sasang Constitutions and Sex Distinction by Body Measurement Method between 3D Body Measuring Instrument and Hand-operating)

  • 권석동;설유경;이의주;김규곤;김종원
    • 사상체질의학회지
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    • v.19 no.1
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    • pp.60-77
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    • 2007
  • 1. Objectives This is the comparative study with hand-operated measurement method and Automatic measurement method, in order to convert the automatic measurement method. 2. Methods We measured the body of patients(hand-operated Width 5 Places and hand-operated circumference 8 place,Automatic Width 5 and automatic circumference 8 place by 3D body measuring instrument) and analyzed the anthropometric data divding into sex&age. 362 patient's data are used in the analysis. 3. Results and Conclusions 1) 1th circumference variable which standing was not a sasang constitutional difference. 2) Diagnostic accuracy rate of the body measurement was 50-80%. 3) Diagnostic accuracy rate of man is higher than Diagnostic accuracy rate of women 4) Diagnostic accuracy rate of Automatic & hand-operated measuring was not a big difference.

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DLP 프린터로 제작된 레진 임시수복물의 3차원적 정확도 평가 (A Study of Three-dimensional evaluation of the accuracy of resin provisional restorations fabricated with the DLP printer)

  • 강월;이희경
    • 대한치과기공학회지
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    • v.42 no.1
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    • pp.35-41
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    • 2020
  • Purpose: The purpose of this study was to evaluate the accuracy of the DLP 3D printer by conducting 3-dimensional assesment of resin provisional restorations. Methods: The first premolar of the maxillary was prepared for the abutment. The abutment was scanned by using a scanner. The provisional restoration was designed by using CAD software. A total of 16 resin provisional restorations were produced using ZD200 and Veltz DLP 3D printer. Scanning was done of resin provisional restorations and 3-dimensional measurement was conducted for accuracy. The mean (SD) of RMS was reported for each group. Independent t-test was used to assess the statistical significance of the results. All analyses were done using SPSS 22.0. Results: The mean ± SD of RMS value for the accuracy of the resin provisional restorations that was fabricated by using ZD200 and Veltz DLP 3D printer were 50.85.±4.64㎛ and 70.33±6.31㎛. Independent t-test showed significant differences between groups(p<0.001). Conclusion: The resin provisional restorations made with DLP 3D printers showed clinically acceptable accuracy.

의료보험자료 상병기호의 정확도 추정 및 관련 특성 분석 -법정전염병을 중심으로- (Estimation of Disease Code Accuracy of National Medical Insurance Data and the Related Factors)

  • 신의철;박용문;박용규;김병성;박기동;맹광호
    • Journal of Preventive Medicine and Public Health
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    • v.31 no.3
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    • pp.471-480
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    • 1998
  • This study was undertaken in order to estimate the accuracy of disease code of the Korean National Medical Insurance Data and disease the characteristics related to the accuracy. To accomplish these objectives, 2,431 cases coded as notifiable acute communicable diseases (NACD) were randomly selected from 1994 National Medical Insurance data file and family medicine specialists reviewed the medical records to confirm the diagnostic accuracy and investigate the related factors. Major findings obtained from this study are as follows : 1. The accuracy rate of disease code of NACD in National Medical Insurance data was very low, 10.1% (95% C.I. : 8.8-11.4). 2. The reasons of inaccuracy in disease code were 1) claiming process related administrative error by physician and non-physician personnel in medical institutions (41.0%), 2) input error of claims data by key punchers of National Medical Insurer (31.3%) and 3) diagnostic error by physicians (21.7%). 3. Characteristics significantly related with lowering the accuracy of disease code were location and level of the medical institutions in multiple logistic regression analysis. Medical institutions in Seoul showed lower accuracy than those in Kyonngi, and so did general hospitals, hospitals and clinics than tertiary hospitals. Physician related characteristics significantly lowering disease code accuracy of insurance data were sex, age group and specialty. Male physicians showed significantly lower accuracy than female physicians; thirties and fortieg age group also showed significantly lower accuracy than twenties, and so did general physicians and other specialists than internal medicine/pediatric specialists. This study strongly suggests that a series of policies like 1) establishment of peer review organization of National Medical Insurance data, 2) prompt nation-wide expansion of computerized claiming network of National Medical Insurance and 3) establishment and distribution of objective diagnostic criteria to physicians are necessary to set up a national disease surveillance system utilizing National Medical Insurance claims data.

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Accuracy Assessment of Global Land Cover Datasets in South Korea

  • Son, Sanghun;Kim, Jinsoo
    • 대한원격탐사학회지
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    • v.34 no.4
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    • pp.601-610
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    • 2018
  • The national accuracy of global land cover (GLC) products is of great importance to ecological and environmental research. However, GLC products that are derived from different satellite sensors, with differing spatial resolutions, classification methods, and classification schemes are certain to show some discrepancies. The goal of this study is to assess the accuracy of four commonly used GLC datasets in South Korea, GLC2000, GlobCover2009, MCD12Q1, and GlobeLand30. First, we compared the area of seven classes between four GLC datasets and a reference dataset. Then, we calculated the accuracy of the four GLC datasets based on an aggregated classification scheme containing seven classes, using overall, producer's and user's accuracies, and kappa coefficient. GlobeLand30 had the highest overall accuracy (77.59%). The overall accuracies of MCD12Q1, GLC2000, and GlobCover2009 were 75.51%, 68.38%, and 57.99%, respectively. These results indicate that GlobeLand30 is the most suitable dataset to support a variety of national scientific endeavors in South Korea.

Establishing Required LOD and Positioning Accuracy for Indoor Spatial Information Applications in Public Administrative Works

  • Park, Junho;Lee, Jiyeong
    • 한국측량학회지
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    • v.35 no.2
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    • pp.103-112
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    • 2017
  • Due to the large size and high complexity of modern buildings, the interest and the studies about indoor spatial information are increasing. Previous studies related to indoor spatial information were mostly about relevant technologies, and the application of indoor spatial information has been less studied. In the present study, the public administrative work areas where indoor spatial information may be applied were identified by using a modified delphi technique. And the indoor LOD (Level of Detail) and indoor positioning accuracy for indoor spatial information applications considering user requirements was established as standards for efficiently establishing and providing services. The required LOD and positioning accuracy for services was established by reestablishing indoor LOD and positioning accuracy and classifying services with reference to those. The indoor LOD was reestablished from LOD 0 to 4 by focusing on service utilization and general recognition, and the positioning accuracy was reestablished in three levels by considering the accuracy of the present positioning technology and service utilization status.