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        검색결과 15

        1.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The CMM is the most widely used measuring device in the field. The three-dimensional measurement method is divided into a method of scanning the shape of a product and a touch method. In this study, the accuracy of the dimension and shape of each measurement point touch method was analyzed based on the measured value with the touch method CMM using the inner and outer diameter measurement specimens. Through the experimental results, it was possible to obtain the closest value to the true value at more than 30 measurement points.
        4,000원
        2.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, measurement errors of the X and Y axes were verified by using an 80-100 mm gauge block, an NPL type angle measuring device, and a spelling on a contact-type 3D measuring device surface plate. In addition, the measurement specimen was repeatedly measured 10 times at 10° intervals from 0° to 40° to confirm the average value and standard deviation. After confirming the statistical test value (P) through ANOVA analysis of the statistical program, the correlation between angle change and error was confirmed.
        4,000원
        3.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was evaluated based on the items of KS B 6389. The study on the calculation of angular error and measurement uncertainty of HRc hardness measurement using statistical techniques using Rockwell measurement specimens with different hardness values ​​was analyzed, and the results were derived according to the change in the angle of the indenter part of the hardness tester and the specimen. As a result of the experiment, the test statistic P values ​​for angle changes such as 0°, 1°, and 2° were all 0.000 using the HRc 30 and 40 measurement specimens, so it was confirmed through the experiment that a significant difference occurred between them. In addition, the extended uncertainty value was calculated as 0.612 at the 95.45% confidence level, and the fact that the hardness test value came out smaller than the existing test value as the inclination angle increased was verified through experiments.
        4,000원
        4.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Failure to comply with the performance test requirements for the centrifugal pumps at power plants often results in performance dissatisfaction as a result of field tests. This study proposed a method of reducing the uncertainty of the field test results by evaluating the systematic error in the measurement system caused by failure to follow the test requirements using the computational fluid dynamics(CFD) technique. As a result of the evaluation of the systematic error and reflecting it in the performance test data, it was confirmed that the error occurred at a constant rate with respect to the flowrate and that the pump, which showed a difference in performance actually had the same performance.
        4,000원
        5.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, using a 100mm gauge block in a contact-type three-dimensional measuring machine surface plate, an NPL-type angle measurement, and a steel ruler, the specimen was measured at 0°, 5°, 10°, 20°, 30°, and 40° along the X and Y axes. After setting the measurement conditions, the average value and standard deviation were confirmed by repeating measurements for each yield 10 times. After checking the statistical test value (P) through ANOVA, the correlation between the angle change and the error was checked.
        4,000원
        8.
        2015.06 구독 인증기관·개인회원 무료
        Measuring body size with a 3D scanner can reduce inter-measurer variability and provide better accuracy compared to using a traditional methods of measurement (Park, Nam, & Park, 2009). Many size measurement projects (or studies) that measure body size established a size measurement method prior to the development of a 3D scanner and automatic size measurement programs that produce 3D virtual body size measurements (Park, &Nam, 2012). Size data measured through an automatic size measurement program are more accurate and have a lower variability that is more appropriate for body measurements (Han, & Nam, 2004; Nam, Choi, Jung, & Yun, 2004). However, this method is limited to healthy subjects who can maintain a correct posture in a 3D scanner. It is difficult for the elderly to maintain the correct posture for body measurements in ‘Basic Human Body Measurements for Technological Design’ of ISO 7250(1997). Body measurement definitions are based on vertical and horizontal directions consequently, it is hard to measure those with a bent body type even if they stand in a correct posture. Most body measurement items are automatically measured in vertical and horizontal directions because current automatic size measurement programs utilize algorithms based on typical body measurement definitions. The size measurement method based on a vertical and horizontal directions tends to have a problem for elderly individuals with a bent body type who have difficulty maintaining a correct posture for 3D scanning as defined in ISO 7250(1997)(Ashdown, & Na, 2008).This study analyzes the problem of present auto-measurement programs that use elderly’s 3D body scan data. We conducted a comparative analysis of elderly’s body sizes using an auto-measurement program from virtual 3D body scan data and direct measurement with traditional measurement methods. We establish 34 typical body size measurements for the use of data from 464 males and 472 females (total 936) between the ages of 70 to 85. For error analysis, data separated to normal values and outliers compared with ISO 20655(2003). ISO 20685 defines the accuracy of extracted measurements by classification and measurement type (segment lengths, body height/breaths/depth, large/small circumferences, and head/hand/foot dimensions). The majority of outliers for the male and female body height type was “height”. Total number of persons with outliers for Height’s data was 603; consequently, 64.4% of subjects (elderly group of 70-85 yrs.) could not maintain a correct posture when scanning. Other data also had many errors from inaccurate measurement postures. A total of 72.3% of males and 70% of females have incorrect values in small circumferences. The segment lengths’ error data was 76.5% of males and 75% of females; in addition, the head dimension’ outliers were 87% for both male and female subjects. Especially 57.46% of males had incorrect data, while 74.67% of females had a type of large circumference. Female chest circumference had significant errors due to sagging breasts. The differences identify with a correlation between type of large circumference (chest, hip, under bust, waist, waist of omphalion) and gender. There were several correlations between the many measurement errors because values over 70% of data have outliers; however, each measurement type has properties in regards to correlation. A substantial positive correlation was found between all measurements (except hip circumference) in the type of large circumference; in addition, one-way ANOVA indicated that the measurements influenced height and were statistically significant. Outliers found in height data for the elderly’s were more likely to have errors in the type of large circumference. The type of body height indicated a strong correlation and statistical significance between the axilla height and other measurements (height, waist, crotch, lateral malleolus). Axilla height with more outliers indicated that other type of body height measurements had a higher potential for errors. The posture for body measurement was standardized as standing erect; however, this study indicated that many measurement errors were possible between using an auto-measurement program and direct measurement. The value of outlier about a particular measurement item can expect increased errors about any group (height: large circumference group/ axilla height: body height group). We have to study the relation in measurements in these types ‘large circumference’ because ‘head dimensions’ types correlate between measurements in each group. We need a more detailed analysis about outliers to find the major factors for measurement errors in regards to the elderly as well as discuss the possibility of ISO measurement-standard’s application for the elderly.
        9.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study is to analyze error cases induced during the proficiency test of certified odor measurement agencies. In the case of the homogeneity test performed in three panel groups, the geometric mean dilution factor of the site boundary PTMs(proficiency testing materials) was 1.4 ± 0.2, 1.7 ± 0.2, 1.8 ± 0.1 and that of the outlet PTMs was 3.7 ± 0.2, 3.7 ± 0.3, 3.7 ± 0.3, respectively. In the case of the stability test for 72 h, the geometric mean dilution factor of the site boundary PTMs was 1.6 ± 0.1 and that of the outlet PTMs was 3.6 ± 0.1. Among error cases induced during the proficiency test of certified odor measurement agencies, the proportion of error cases was in the order of case II(discontinuance of estimation)(40.0%) > case I(error on estimation procedure by panelist)(33.3%) > case III(miswriting of estimation result)(13.3%) > case IV(miswriting of dilution factor) and V(writing of wrong estimation result)(6.7%). Therefore, it seems likely that additional education related to error cases II and I is required.
        4,000원
        10.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Location-Based Service(LBS) is a service that provides a variety of convenience in life using location information that can be obtained by mobile communication network or satellite signal. In order to provide LBS precisely and efficiently, we need the location determination technology, platform technology and server technology. In this study, we studied on how we can reduce the error on location determination of objects such people and things. Fingerprint location determination method was applied to this study because it can be used at current wireless communication infrastructure and less influenced by a variety of noisy environment than other location determination methods. We converted the probability value to logarithmic scale value because using the sum of k probability values is not suitable to be applied to weight determination. In order to confirm the performance of suggested method, we developed location determination test program with Visual Basic 6.0 and performed the test. According to indoor and outdoor test results, the suggested stochastic method reduced the distance error by 17%, 18% and 9% respectively at indoor environment and 25%, 11% and 4% at outdoor environment compared with deterministic NN, kNN and kWNN fingerprint methods.
        4,000원
        11.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We develop methods for propagating and analyzing EPCI(Extended Process Capability Index) by using the error type that classifies into accuracy and precision. EPCI developed in this study can be applied to the three combined processes that consist of production, measurement and calibration. Little calibration work discusses while a great deal has been studied about SPC(Statistical Process Contol) and MSA(Measurement System Analysis). EPCI can be decomposed into three indexes such as PPCI(Production Process Capability Index), PPPI(Production Process Performance Index), MPCI(Measurement PCD, and CPCI(Calibration PCI). These indexs based on the type of error classification can be used with various statistical techniques and principles such as SPC control charts, ANOVA(Analysis of Variance), MSA Gage R&R, Additivity-of-Variance, and RSSM(Root Sum of Square Method). As the method proposed is simple, any engineer in charge of SPC. MSA and calibration can use efficientily in industries. Numerical examples are presentsed. We recommed that the indexes can be used in conjunction with evaluation criteria.
        4,000원
        12.
        2019.04 서비스 종료(열람 제한)
        The camera movement can cause considerable error in the computer vision-based displacement measurement because the camera is generally placed far from the region of interest. The camera movement, which is difficult to avoid particularly in the long-term measurement, hinders real-world applications of the computer vision-based displacement method. This research proposes a practical means of long-term displacement measurement by using a novel camera system. In addition to the conventional camera-based measurement, an auxiliary camera is used to compensate the camera motion-induced error. Experimental validation is conducted in the laboratory environment.
        13.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        This study aims to analyze region-specific trends in changing greenhouse gas emissions in incineration plants of local government where waste heat generated during incineration are reused for the recent five years (2009 to 2013). The greenhouse gas generated from the incineration plants is largely CO2 with a small amount of CH4 and N2O. Most of the incineration plants operated by local government produce steam with waste heat generated from incineration to produce electricity or reuse it for hot water/heating and resident convenience. And steam in some industrial complexes is supplied to companies who require it for obtaining resources for local government or incineration plants. All incineration plants, research targets of this study, are using LNG or diesel fuel as auxiliary fuel for incinerating wastes and some of the facilities are using LFG(Landfill Gas). The calculation of greenhouse gas generated during waste incineration was according to the Local Government's Greenhouse Emissions Calculation Guideline. As a result of calculation, the total amount of greenhouse gas released from all incineration plants for five years was about 3,174,000 tCO2eq. To look at it by year, the biggest amount was about 877,000 tCO2eq in 2013. To look at it by region, Gyeonggido showed the biggest amount (about 163,000 tCO2eq annually) and the greenhouse gas emissions per capita was the highest in Ulsan Metropolitan City(about 154 kCO2eq annually). As a result of greenhouse gas emissions calculation, some incineration plants showed more emissions by heat recovery than by incineration, which rather reduced the total amount of greenhouse gas emissions. For more accurate calculation of greenhouse gas emissions in the future, input data management system needs to be improved.
        14.
        2014.04 KCI 등재 서비스 종료(열람 제한)
        Fixed Electromagnetic Wave Surface Velocimetry (Fixed EWSV) has been started to be used to measure flood discharge in the mountain stream, since it has various advantages such that it works well to continuously measure stream discharge even in the night time as well as very strong weather. On the contrary, the Fixed EWSV only measures single point surface velocity, thus it does not consider varying feature of the transverse velocity profile in the given stream cross-section. In addition, a conventional value of 0.85 was generally used as the ratio for converting the measured surface velocity into the depth-averaged velocity. These aspects could bring in error for accurately measuring the stream discharge. The capacity of the EWSV for capturing rapid flow velocity was also not properly validated. This study aims at conducting error analysis of using the EWSV by: 1) measuring transverse velocity at multiple points along the cross-section to assess an error driven by the single point measurement; 2) figuring out ratio between surface velocity and the depth-averaged velocity based on the concurrent ADCP measurements; 3) validating the capacity of the EWSV for capturing rapid flow velocity. As results, the velocity measured near the center by the fixed EWSV overestimated about 15% of the cross-sectional mean velocity. The converting ratio from the surface velocity to the depth-averaged velocity was 0.8 rather than 0.85 of a conventional ratio. Finally, the EWSV revealed unstable velocity output when the flow velocity was higher than 2 m/s.