• Title, Summary, Keyword: accuracy-study

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A STUDY ON THE RADIOGRAPHIC DIAGNOSIS OF COMMON PERIAPICAL LESIONS BY USING COMPUTER (컴퓨터를 이용한 주요 치근단 병소의 방사선학적 진단에 관한 연구)

  • Kim Seung Kug;Kim Jae Duk
    • The Journal of Korean Academy of Maxillofacial Radiology
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    • v.20 no.2
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    • pp.277-287
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    • 1990
  • The purpose of this study was to estimate the diagnostic availability of the common periapical lesions by using computer. The author used a domestic personal computer and rearranged the applied program appropriately with RF (Rapid File), a program to answer the purpose of this study, and then input the consequence made out through collection, analysis and classification of the clinical and radiological features about the common periapical lesions as a basic data. The 256 cases (Cyst 91, Periapical granuloma 74, Periapical abscess 91) were obtained from the chart recordings and radiographs of the patients diagnosed or treated under the common periapical lesions during the past 8 years (1983-1990) at the infirmary of Dental School, Chosun University. Next, the clinical and radiographic features of the 256 cases were applied to RF program for diagnosis, and the diagnosis by using computer was compared with the hidden final diagnosis by clinical and histopathological examination. The obtained results were as follows: 1. In cases of the cyst, diagnosis through the computer program was shown rather lower accuracy (80.22%) as compared with accuracy (90.1 %) by the radiologists. In cases of the granuloma, diagnosis through the computer program was shown rather higher accuracy (75.7%) as compared with the accuracy (70.3%) by the radiologists. 2. In cases of periapical abscess, the diagnostic accuracy was shown 88% in both diagnoses. 4. The average diagnostic accuracy of 256 cases through the computer program was shown rather lower accuracy (81.2%) as compared with the accuracy (82.8%) by the radiologists. 5. The applied basic data for radiographic diagnosis of common periapical lesions by using computer was estimated to be available.

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A study on the Accuracy Improvement of Three Dimensional Positioning Using SPOT Imagery (SPOT 위성영상(衛星映像)을 이용(利用)한 3차원(次元) 위치결정(位置決定)의 정확도(正確度) 향상(向上)에 관(關)한 연구(硏究))

  • Yeu, Bock Mo;Cho, Gi Sung;Lee, Hyun Jik
    • Journal of The Korean Society of Civil Engineers
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    • v.11 no.4
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    • pp.151-162
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    • 1991
  • This study aims to improve the positioning accuracy by analizing the accuracys of three dimensional positioning according to various data types and preprocessing levels of SPOT imagery and the acquisition method for ground control points, and to develop the three dimensional positioning algorithm and program. In this study, the optimum polynomials of exterior orientation parameters according to each preprocessing levels (level 1B; 15 variables, level 1AP, 1A; 12 variables) are determined. As a results, the accuracy of level lAP is the best in the results of analysis about the accuracy of positioning, but level 1A which is digital image data form also shows similar positioning accuracy. Also, in level 1A image which have different acquisition method for ground control points, the accuracy of three dimensional positioning is highly improved. But, in case of low accuracy of ground control points, only introduction of additional parameters does not effect to the improvement of accuracy. Therefore simultaneous adjustment including blunder detection method should be adopted.

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A Study on the Diagnostic Accuracy Rate of the Sasang Constitution Questionnaire for Doctors Used in the On-line System (온라인 진단시스템에 사용되는 의사용 체질진단함수의 진단정확률 연구)

  • Jeon, Soo-Hyung;Jeong, Seong-Il;Kwon, Seok-Dong;Park, Se-Jung;Kim, Kyu-Kon;Kim, Jong-Won
    • Journal of Sasang Constitutional Medicine
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    • v.20 no.3
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    • pp.82-93
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    • 2008
  • 1. Objective The purpose of this study was to develop and upgrade the On-line SSCQ (Sasang Constitution Questionnaire) by making an analysis of diagnostic accuracy rate of Sasang Constitution Questionnaire for doctors. 2. Methods We have collected SSCQ-D(Sasang Constitution Questionnaire for Doctors) from the dept. of Sasang constitutional medicine in the four other university. We classified data according to Sasang constitution, sex, age and BMI and made an analysis using the chiefly discriminant analysis model, additionally frequency analysis, and Cronbach's alpha coefficient. 3. Results and Conclusion 1) Diagnostic accuracy rate of the SSCQ-D was between 71.33 and 95.14%. (1) About the whole subject the accuracy rate was 71.33%. (2) About the whole female the accuracy rate was 73.26%. (3) About the whole male the accuracy rate was 81.41%. 2) The more classification variables we used in this analysis study, the higher the diagnostic accuracy rate increased.

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A Study on Status and Accuracy of Underground Facilities Maps (지하시설물도 현황 및 정확도 분석에 관한 연구)

  • Lee, Yong-Wook;Heo, Min;Lee, Jae-One;Bae, Kyoung-Ho
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.25 no.3
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    • pp.223-230
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    • 2007
  • As the centralization of city, underground facilities is increasing and being more important. Although the importance of underground facilities map has been emphasized, there were many accidents related underground facilities. The inaccuracy of existing data and the carelessness of management caused many accidents. It is very important to update and to have high quality accuracy of underground facilities maps. But the underground facilities maps are mapped and updated by each institutes. So it is difficult to verify the accuracy of the data. In this study, Field Test is performed to analyze the horizontal accuracy of existing maps using Electromegnetic Induction Method, Total Station and GPS. Surveying of underground facilities in Seoul was performed for 6 institutes of underground facilities during 3 years. The aim of this study is to verify the horizontal accuracy of data and to improve the accuracy of underground facility maps. As the result of analysis, the horizontal accuracy of 6 underground facilities management institutes is 73 cm(2004), 78 cm(2005) and 75 cm(2006).

A Study on Accuracy of Meteorological Information for Low Altitude Aerospace around the Airport on the West Coast (서해안 인접공항의 저고도 항공기상 정확도 연구)

  • Cho, Young-Jin;Yoo, Kwang Eui
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.28 no.2
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    • pp.53-62
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    • 2020
  • This study is to evaluate the accuracy of the meteorological information provided for the aircraft operating at low altitude. At first, it is necessary to identify crucial elements of weather information closely related to flight safety during low altitude flights. The study conducted a survey of pilots of low altitude aircraft, divided into pre-flight and in-flight phases, and reached an opinion that wind direction, wind speed, cloud coverage and ceiling and visibility are important items. Related to these items, we compared and calculated the accuracy of TAFs and METARs from Taean Airfield, Seosan Airport and Gunsan Airport because of their high number of domestic low-altitude flights. Accuracy analysis evaluated the accuracy of two numerical variables, Mean Absolute Error(MAE) and Root Mean Square Error(RMSE), and the cloud coverage which is categorical variable was calculated and compared by accuracy. For numeric variables, one-way ANOVA, which is a parameter-test, was approached to identify differences between actual forecast values and observations based on absolute errors for each item derived from the results of MAE and RMSE accuracy analyses. To determine the satisfaction of both normality assumptions and equivalence variability assumptions, the Shapiro-Wilk test was performed to verify that they do not have a normality distribution for numerical variables, and for the non-parametric test, Kruscal-Wallis test was conducted to determine whether or not they are satisfied.

A Study on Roughness Characteristic about Rotational Accuracy Variation (스핀들의 회전 정밀도에 따른 표면 거칠기 특성 연구)

  • Park, Ki-Beom;Chung, Won-Jee;Lee, Choon-Man
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.18 no.1
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    • pp.110-115
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    • 2009
  • In general, the radial error motion of a machine tool spindle system is effected on the accuracy of the parts to be made. This paper presents in milling process an investigation into spindle rotational accuracy effects on surface roughness of processing parts. We experimented the effects on spindle rotational accuracy in milling process by cutting AL 7075 workpiece at various rotational speed. In order to analyze the effects of rotational accuracy on surface roughness, we proposed the method using iSIGHT's RBF Approximation. The proposed method can be used fur anticipating the surface roughness when some spindle rotational accuracy experiments could be done in milling process.

A Study on the Development of Hourly Evaporation Recording Instrument for Class A Pan (대형증발계용 매시간 증발 기록계 개발에 관한 연구)

  • Bu-Yong Lee
    • Journal of Environmental Science International
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    • v.10 no.5
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    • pp.323-327
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    • 2001
  • A new method is developed to estimate the evaporation of water from a surface with high accuracy and resolution. The principle of new method is to detect a weight change of buoyant weight according to a change in water level of Class A Pan mesured by the use of a strain-gauge load cell. Field test of evaporation recording new instrument was carried out at Suwon for 10 days July 1999. It is possible in field observation to measure hourly evaporation amount by newly developed evaporation recording instrument in Class A Pan against strong solar radiation. Present study provide a possibility of domestic high accuracy instrument development below than 0.1mm water level measurement accuracy. If there is low humidity and high wind speed conditions which is possible to evaporate from water surface during night time. And it needs continuous study to understand between meteorological elements and latent heat effect at ground level by field observation study using high accuracy evaporation recording instrument.

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A Study on Accuracy Analysis of DGPS-Based Marine Radiobeacon in the East Coast of Korea (한국동해안에서의 Marine Radiobeacon/DGPS 정밀도 분석에 관한 연구)

  • 고광섭;이형욱;정세모
    • Journal of the Korean Institute of Navigation
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    • v.22 no.1
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    • pp.1-13
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    • 1998
  • Radiobeacons that carry corrections for global satellite navigation systems are currently being planned or installed in many countries. In early 1996, it was begun to send DGPS correction message from a marine radiobeacon station located in Changgi Got Lighthouse. It was the first test broadcast of DGPS correction data based on medium frequency of marine radiobeacon where transmission power and rate are 300W and 100bps respectively in Korea. However, there has not been any scientific study on the characteristic of the accuracy of a marine radiobeacon/DGPS. Accordingly, this paper investigates the accuracy of the system, which is currently operating in 310kHz. To do this , the real time differential correction in RTCM data was collected in an implemented system. And then the accuracy was analyzed related to the coverge of the radiobeacon/DGPS. As a result, it is verified that the differential positioning accuracy using the marine radiobeacon is sufficient to ensure the safety of marine activities around the coast of Korea.

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A study on temporal accuracy of OpenFOAM

  • Lee, Sang Bong
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.9 no.4
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    • pp.429-438
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    • 2017
  • Cranke-Nicolson scheme in native OpenFOAM source libraries was not able to provide 2nd order temporal accuracy of velocity and pressure since the volume flux of convective nonlinear terms was 1st accurate in time. In the present study the simplest way of getting the volume flux with 2nd order accuracy was proposed by using old fluxes. A possible numerical instability originated from an explicit estimation of volume fluxes could be handled by introducing a weighting factor which was determined by observing the ratio of the finally corrected volume flux to the intermediate volume flux at the previous step. The new calculation of volume fluxes was able to provide temporally accurate velocity and pressure with 2nd order. The improvement of temporal accuracy was validated by performing numerical simulations of 2D Taylor-Green vortex of which an exact solution was known and 2D vortex shedding from a circular cylinder.

A Study on the Positioning Accuracy and table Deflection by Load (하중에 의한 위치결정오차와 테이블 처짐에 관한 연구)

  • 전언찬
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.8 no.6
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    • pp.98-104
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    • 1999
  • As the accuracy of manufactured goods needed high accuracy processing has made the efficiency of NC and measurement technology development, the innovation of machine tools has influence the development of the semi-conductor and optical technology. The movement errors can be expressed in terms of yaw, roll an pitch etc. In the case of expanding the error range, static, dynamic and servo gain errors can be included. Machining center might have twenty-one movement errs including three types of joint errors. Those errors have been measured on the condition of just loading of standard table. Regarding these measuring methods, the mechanical compliance of the structure has not been considered. In this paper, therefor, the influences of the additional load on the positioning accuracy are investigated. The results and the techniques proposed in this study can be considered very effective and useful to compensate more correctly the positioning motion.

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