In this study, data on indication errors within the range of 0 to 10 mm were measured using a dial gauge, which is widely used as a comparative measuring instrument in the field. Using Minitab, a statistical program, measurement conditions were determined during calibration of measuring instruments. Since the P value of the test statistic for the indication error is 0.000 to 0.003, the alternative hypothesis (H1) that no significant difference occurs due to a change in the measurement point at the significance level of 0.05 was adopted.
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.
The Republic of Korea is implementing safeguards for domestic nuclear facilities through cooperation with the IAEA. But it is not to evaluate the material balance for the material unaccounted for, MUF in the bulk handling facility. Although the development of a material balance evaluation program is underway, there are no related regulations. The State Regulatory Authority, SRA is performing material balance evaluation, MBE on the facility based on the design information and material balance results of the facility. However, it is not possible to directly derive measurement uncertainty for the facility’s measurement equipment, which is an important variable of MBE. To solve this problem, it is trying to derive a method suitable for the domestic environment by investigating the some measurement uncertainty estimation methods and analyzing characteristics of them. In this study, the traditional measurement uncertainty estimation method, GUM method and GUM-S1 method were studied and the advantages and disadvantages were analyzed. Due to the problems mentioned above, the uncertainty quantification technique currently being used cannot be applied to the evaluation of the domestic material balance. Therefore, we are tying to apply them to the evaluation the domestic material balance through the above three methods or a combination of them appropriately. Through this continuing study, it is expected that it will be possible to present a plan to derive measurement uncertainty optimized for the domestic MBE environment.
With the advancement of industrialization, modern industry had sophisticated technology, and manufacturers also demanded high-precision measurement accuracy. Improving the quality level by increasing the reliability of measurement results as well as accurate measurement is a key issue to increase the competitiveness of today's manufacturing industry. In general, measurement results depend on tolerances in the industrial field, and it may be difficult to guarantee the reliability of the data in the case of an industry that deals with precision parts. Currently, measurement uncertainty is mainly applied to the calibration and test fields of instruments. This study is aim to apply measurement uncertainty as a way to improve the accurate analysis and reliability of measurement results in the industrial field. For this, precision parts connected by shaft and hole were selected among geometric elements, and roundness and cylindricity were measured using a roundness measuring instrument and CMM. And, taking into account the environment in which these measurements were made, factors affecting the measurement results were derived, and a mathematical model was established to calculate the measurement uncertainty. Applying uncertainty in the field in this way is expected to improve the level of quality and accurate analysis of measurement results.
Sea trial tests are necessary to verify speed-power performance, and are an import contract between ship owners and shipyards. The International Organization for Standardization (ISO) published ISO 15016:2015, which specifies the correlation method between model and full-scale ships. The results of sea trials have been questioned because of the uncertainty of speed and power measurements, especially when sea conditions differ from ideal calm water conditions. In this paper, such uncertainties were investigated by utilizing the standard speed-power trial analysis procedure defined in ISO 15016:2015 through Monte Carlo simulations. It was found that the expanded uncertainty of the delivered power (PDid) at 95 % confidence interval (k = 2) was ±1.5 % under 75 % MCR conditions.
All measurements include uncertain factors affecting the result in accordance with environment and conditions. In order to guarantee right decision making and quality improvement, these factors must be found and appropriate actions should be taken. This paper aims to estimate and analyze variabilities found in set-up and as well as measurement uncertainty when using CMM(Coordinate Measuring Machine). Two skilled operators were selected to individually measure a product which was a kind of main part of an engine called connecting rod cap. The results showed that at the least, 10 % was stable while at the most, 30 % was somewhat unstable regarding P, percentage of measuring errors. There was little difference between the two operators on measurement uncertainty expecially considering their degree of freedom based on their objective and subjective judgement of type B uncertainty despite the significant difference between them. Through this research, I have come to a conclusion that a much more detailed analysis on variation factors can be identified in general measurement by using CMM and the result of set-up variability demands specific investigation and efforts to improve operators’ skill or thorough examination on the method of setting product to minimize set-up variability later.
There can be included a variety of uncertainties in all measurement results whether we can perceive or not on the causes. These uncertainties may end up in lowering the reliability of measurement results and also deteriorate the level of quality. For the purpose, we tried to combine the strengths of measurement uncertainty and measurement system analysis together to present a practical flowchart so as to verify those potential variation factors in general measurement processes. As a case study, we did an experiment and gathered data on the length between two holes of an engine cylinder head which is a core part for vehicles with a coordinate measuring machine and estimated nine uncertainty factors of it. Consequently, it was identified that the four primary factors among the nine which were related to the measurement standard, random errors or spread of the repeat measurements, differences between the coefficients of thermal expansion and the environment especially had been the influence around the laboratory. Since it is impossible to analyze the equipment and appraisal variations respectively through the only measurement uncertainty, we have used the measurement system analysis following the flowchart. Showing the result of being just about 0.5 % lower for the appraisal variation, and the equipment variation occupied about 7% for the total Gage R&R. Through this research, we have come to a conclusion that much more detail analysis on variation factors can be possible to be identified in measurement processes by using the developed flowchart which is composed of measurement uncertainty and measurement system analysis. Therefore, we expect engineers who are involved in quality and measurements to utilize this developed method.
There can be included a variety of uncertainties in all measurement results whether we can perceive or not on the causes. These uncertainties may end up in lowering the reliability of measurement results and also deteriorate the level of quality. For the purpose of finding and improving these causes , we tried to combine the strengths of measurement uncertainty and measurement system analysis together to present a practical flowchart so as to verify those potential variation factors in general measurement processes. Through the case study we have come to a conclusion that we can expect engineers who are involved in quality and measurements to utilize this developed method.
This research presents efficient use of coverage factor of expanded uncertainty. Process Capability Indexes(PCIs) are newly introduced in this paper to take in consideration of either including correction and uncertainty of calibration or not for deciding bilateral specification, upper specificand and lower specification.
본 연구에서는 차량검지기의 속도측정 성능평가방법을 개발하였다. 개발된 성능평가방법에서는 오차요인들을 기준속도에 반영하며 측정불확도의 개념을 적용하였다. 기존연구, 통계적 처리기법, 기존교통단속장비 및 차량검지시스템의 속도측정 성능평가방법 등에 대한 고찰을 통해 기존평가방법의 문제점을 도출하고 개선된 성능평가방법을 개발하였다, 실제 현장에 설치된 차량검지기에 대해서 기존평가방법과 개발방법을 적용해본 결과 기존평가방법은 평가기준에 적합하나 개발방법은 평가기준을 만족시키지 못하고 있다. 이러한 결과는 기존성능평가방법이 측정 시의 오차요인들을 충분히 고려하지 못해서 평가대상장비의 성능을 고평가할 가능성이 있음을 의미하며, 반면에 개발모형은 측정 시의 변동요인인 오차를 고려하므로 기존평가방법 보다 정확함을 나타낸다.
Carbon contamination from the binder resin is an inherent problem with the metal powder injection molding process. Residual carbon in the W-Cu compacts has a strong impact on the thermal and electric properties. In this study, uncertainty was quantified to evaluate determination of carbon in a W-15%Cu MIM body by the combustition method. For a valid generalization about this evaluation, uncertainty scheme applied even to the repeatability as well as the uncertainty sources of each analyse step and quality appraisal sources. As a result, the concentration of carbon in the W-Cu part were measured as 0.062% with expanded uncertainty of 0.003% at 95% level. This evaluation example may be useful to uncertainty evaluation for other MIM products.
This paper is to propose model classification and evaluation of measurement uncertainty. In order to obtain type A and B uncertainty, variety of measurement mathematical models are illustrated by example. The four steps to evaluate expanded uncertainty are indicated as following; First, to get type A standard uncertainty, measurement mathematical models of single, double, multiple, design of experiment and serial autocorrelation are shown. Second, to solve type B standard uncertainty measurement mathematical models of empirical probability distributions and multivariate are presented. Third, type A and B combined uncertainty, considering sensitivity coefficient, linearity and correlation are discussed. Lastly, expanded uncertainty, considering degree of freedom for type A, B uncertainty and coverage factor are presented with uncertainty budget. SPC control chart to control expanded uncertainty is shown.
Uncertainty evaluation was performed for the measurement of Volatile Organic Compounds(VOC) in indoor air. The analytical procedure and result were validated by evaluating every uncertainty source related to the measurement method. An easy approach for uncertainty evaluation for indoor VOC measurement was tested using relative standard uncertainty method which is simple in the evaluation of a measurement uncertainty in case of indoor VOC measurement. The measurement uncertainties of toluene, ethylbenzene, m+p-xylene, styrene and o-xylene in indoor air are obtained as less than or close to 10%, and those results were validated by using Gum-workbench uncertainty evaluation program. Based on the evaluation, uncertainties were found to come largely from two major sources, uncertainty related to the concentration of standard Tenax tube which was used for calibration in measurement, and the to air sampling process. This study could be used as a good example in evaluating uncertainties in the measurement of indoor-air VOC at buildings including a newly-built apartment.
The ISO 'Guide to the Expression of Uncertainty in Measurement (GUH) establishes a unified method for evaluating uncertainty in measurement worldwide. This paper discusses the concepts and procedures of uncertainty evaluation.
음향 도플러 유속계(Acoustic Doppler Current Profiler, ADCPs)는 하천의 유량측정에 널리 사용되고 있으나, 유량 측정성과의 불확도를 평가하는 방 법에 대하여 진행된 연구는 부족한 현실이며, 이는 실제 하천에서 유속 및 유량 등의 수리량을 조절하는 것이 현실적으로 불가능하여 ADCP의 불확도 요인 별 실험 및 분석이 어렵기 때문이다. 유량 및 수리량의 측정 불확도를 평가하기 위하여 과학 및 공학 분야에서는 다양한 연구들이 진행되어 왔으며, 그 중 국 제적으로 공인받고 있는 방법 중 하나가 GUM (Guide to the Expression of Uncertainty Measurement)이다. 본 연구에서는 GUM 표준안을 기반으로 ADCP의 유량 측정 불확도를 평가하기 위한 연구를 수행하였다. ADCP의 유량 측정 불확도 요인별 분석을 수행하기 위하여 유량 공급의 조절이 가능한 실 규모 수로를 보유하고 있는 하천실험센터에서 실험을 진행하였으며, ADCP의 측정 정확도에 영향을 미치는 수심, 측정 지점에서 하안까지의 거리, ADCP 의 잠김 깊이, 유속 오차, 측정 시간, 반복 횟수, 하상 조건 등에 대한 측정 정확도 평가 실험을 수행하였다. ADCP로 유량을 측정하는 방법은 지점측정방식 을 기반으로 유속-면적법을 통해 산정하는 방법과 일반적으로 사용되는 이동측정방식이 있으며, 본 연구에서는 ADCP의 지점측정방식을 통해 유량을 산정 하는 Section-by-Section 방법으로 산정된 유량의 불확도를 평가하였다. 모든 측정 결과는 요인별 불확도 평가를 수행하기 위하여 유속은 ADV, 수심은 광 파기로 측정된 결과와 비교하였다.
본 연구에서는 현장에서 실측된 유량 및 수위로부터 산정된 조도계수의 오차를 분석하고 그 타당성과 한계를 검토하였다. 자연 하천흐름을 등류로 가정하여 산정된 조도계수는 저유량 규모에서 부등류로 계산된 조도계수와 큰 차이를 나타내었으며, 이는 속도수두의 차이보다 평균 단면적, 동수반경 등 단면정보에 크게 영향을 받았다. 상대적으로 긴 구간에서 홍수량 규모의 평균 조도계수 산정에서는 구간 상하류만의 수위 자료를 이용하여 조도계수를 산정하는 수정 Newton-