Earticle

본 연구는 고속축중기(HS-WIM) 성능평가 자료를 활용하여 축하중 분포 구조가 계측 오차 에 미치는 영향을 분석하였다. 기준 축하중의 변동계수를 기반으로 축하중 분포 불균형지수 (ICV)를 정의하고, 이를 4분위로 구분하여 축별 및 총중량 절대상대오차 특성을 비교하였다. 또 한 축별 오차가 총중량 오차로 반영되는 구조를 분석하기 위해 오차 상쇄 지수를 도입하였다. 분석 결과, 축하중 분포 불균형이 증가하더라도 축별 오차의 크기는 일관되게 증가하지 않았 으며, 오히려 불균형이 큰 구간에서는 축별 오차 상쇄 효과로 인해 총중량 오차가 상대적으로 작게 나타났다. 또한 ICV와 축별 오차 간에는 약한 음의 상관관계가 확인되었으나 그 영향력은 제한적인 것으로 나타났다. 이러한 결과는 현행 성능평가 체계가 축중량과 총중량을 모두 평 가함에도 불구하고, 개별 지표만으로는 오차의 구조적 특성을 충분히 설명하기 어려움을 시사 한다. 따라서 HS-WIM 계측 결과의 해석 및 활용 시 축하중 분포 구조와 오차 상쇄 특성을 함 께 고려할 필요가 있다.

This study analyzes the influence of axle load distribution characteristics on measurement errors using performance evaluation data from a High-Speed Weigh-In-Motion (HS-WIM) system. An axle load distribution imbalance index (ICV) was defined based on the coefficient of variation of reference axle loads, and the dataset was classified into quartiles according to the ICV to compare axle-wise and gross vehicle weight (GVW) absolute relative errors. In addition, an error cancellation index was introduced to examine the structural relationship between axle-wise errors and GVW error. The results indicate that axle-wise errors do not consistently increase with increasing imbalance in axle load distribution. In highly imbalanced conditions, GVW error tends to be relatively small due to the cancellation effect among axle-wise errors. Furthermore, a weak negative correlation between ICV and axle-wise errors was observed, although its influence was limited. These findings suggest that, although current HS-WIM performance evaluation frameworks assess both axle loads and GVW, interpretation based solely on individual error metrics may not fully capture the structural characteristics of measurement errors. Therefore, it is necessary to consider axle load distribution and error cancellation effects when interpreting and utilizing HS-WIM measurements

Measurement error is one of main source of error in survey. It is generally defined as the difference between an observed value and an underlying true value. An observed value with error may be expressed as a function of the true value plus error term. In some cases, the measurement error variance may be also a function of the unknown true value. The error variance function can be rewritten as a function of true value multiplied by a scale factor. This research explore methods for estimation of the measurement error variance based on the data from complex sampling design. We consider the case in which the variance of mesurement error is a linear function of unknown true value, and the error variance scale factor is small. We applied our results to the U.S. Third National Health and Nutrition Examination Survey (the U.S. NHANES Ⅲ) data for empirical analyses, which has replicate measurements for relatively small subset of initial respondents's group.

Modular system refers to the method of pre-configuring the building's base frame, plumbing, insulation and finishing materials in the factory and assembling them on site. In the field assembly, mainly bolted joints are used, and in the event of bolting problems, not only fade the advantages of the modular system, but also adversely affect the joint strength between the modular units. Therefore, in this paper, a system that can detect the manufacturing error of bolt arrangement and analyze the measurement error before the bolt fastening of the modular unit was conducted. An algorithm capable of analyzing image to measure bolt arrangement by receiving images in real time through a camera module that can photograph each modular column and a single board computer was developed. Bolt size, bolt distance, edge distance, modular frame size and perpendicularity were measured. The bolt distance was 0.46mm, 0.22%, and the bolt size was 0.15mm, which was almost accurate with 0.7% error.

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.

3차원 측정기는 물체의 표면 위치를 검출하는 기능을 가진 센서가 3차원 공간을 움직이면서 측정점을 좌 표를 검출하고 컴퓨터를 통해 그 데이터를 처리함으로써 크기나 위치, 방향 등을 측정하는 측정기이다.[1] 복잡한 형 상의 부품에 대한 기하학적 특성을 공간좌표 상에서 쉽게 측정할 수 있도록 제작된 측정기가 3차원 측정기 이며, 역설계, 제품의 품질관리, 제품의 신뢰도확보, 제품평가를 위해 3차원 측정기의 활용도가 중시되고 있다. 하지만 3 차원 측정기의 활용에 측정 정밀도 및 신뢰성 미흡은 3차원 측정기의 활용을 어렵게 한다. 3차원 좌표측정기의 측 정 정밀도는 실제 사용자의 숙련도에 의존 할 수 있으나 더 큰 원인은 측정을 위한 측정조건이라고 할 수 있다. 특히 온도는 3차원 좌표측정기의 측정에 중요한 조건이며, 본 연구에서는 고온 측정물이 측정오차에 미치는 영향 에 대해 연구하였다. 그 결과 측정값의 오차 변형률 및 불확도가 30～50℃ 사이에서는 불확도가 크게 나타났다.

Three dimensional coordinate measuring machine is a measuring instrument that measures size, location, direction with the sensor that has detection function of location of object on the surface by moving three dimensional space as detecting the coordinates of measurement point and running the data through computers. Three dimensional coordinate measuring machine was designed to measure geometrical characteristics of component with a complex shape on spatial coordinates, so the availability of three dimension measuring instrument is getting more important for reverse engineering, quality control of the product, ensuring reliability of product, manufacture evaluation. But measurement of precision of 3dimension measuring instrument and insufficiency of reliability make the use of 3 dimension measuring instrument harder. The measurement precision of three dimensional coordinate measuring machine can rely on the skills of the actual user, but the bigger cause is the measuring condition for measurement. Especially, temperature is a crucial condition and in this study, I did research on the effect that high temperature measure object affects measurement errors. As a result, The error strain and uncertainty of the measured value were large between 30 and 50 °C. So it seems to be very important to keep the condition at a standard temperature when we measure these kinds of materials. The result of this study is to minimize measurement errors on three dimensional coordinate measuring machine. and I expect it would contribute to its reliability improvement.

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.

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.

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.

구간통행속도는 도로의 교통상황을 나타내는 중요한 지표이며, UTIS(Urban Traffic Information System)는 도로의 구간통행속도를 측정하여 제공하는 대표적인 구간속도 측정시스템이다. 시험운영 결과, 프로브 차량의 불규칙한 주행궤적, 무선통신 장치의 통신범위 등의 요인으로 UTIS 산출 속도의 신뢰도가 저하되는 현상이 일부 나타나고 있다. 본 논문에서는 이러한 오차를 줄이기 위해 UTIS에 포함된 이상치를 제거하는 알고리즘을 제안하였다. 제안된 알고리즘을 적용하여 현장실험을 실시한 결과 새로운 이상치 제거 알고리즘이 속도 측정값들 오차백분율의 분산을 기존 알고리즘보다 2배이상 줄여주는 것으로 분석되었다. 이는 새로운 알고리즘이 이상치를 적절히 처리하여 구간통행속도 산출 정확도를 높여줌을 나타낸다.

Travel speed is an important parameter in measurement of road traffic. UTIS(Urban Traffic Information System) was developed as a type of section detector. However, UTIS incur errors caused by irregular vehicle trajectories, wireless communication range and so on. This paper suggests a new model that use an error-filtering algorithm to improve the accuracy of travel speed measurements. In the field test, the variance of the percent errors measured by the new model was reduced. Therefore, it can be concluded that the proposed model significantly improves travel speed measuring accuracy.

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.

The results of the measurements using an optical surface roughness meter are shown according to the angle changes of 0, 0.5, 1, 1.5, 2, and 3°. Through the experiment, it can be seen that the measurement value is 3.140 at 0°, 3.148 at 0.5°, 3.140 at 1°, 3.151 at 1.5°, 5.078 at 2°, and 4.790 at 3° setting. In addition, the test statistic (P) value is 0.000, which is smaller than the significance level of 0.005, so it was confirmed through the experiment that a measurement error occurs according to the angle change when measuring the surface roughness.

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.

탄광, 지하실, 지하창고 등 위험한 지역에서 일하는 일군들의 움직임을 비롯한 위치 측정은 안전을 위해 반드시 필요한 기술이다. 위험하고 제한된 환경에서의 USN의 위치 측정 기법들은 다양하게 존재한다. 위치 측정 기법 중에 삼각측량법은 간단하기 때문에 여러 분야에서 많이 적용되고 있다. 하지만 측정기구와 전파 장애 및 물리적 장애로 인해 오차가 발생하여 정확한 위치를 파악하기 어렵다. 본 논문에서는 4개의 Anchor와 움직이는 노드 사이의 거리 정보를 다양하게 활용하여 재계산하여 기존 삼각측량법으로 얻은 위치보다 오차범위를 줄일 수 있는 방법을 제안한다. 또한 제안 기법을 통해 거리 측정하여 움직이는 노드의 위치 즉, 예측점을 계산하였을 때는 기존 삼각측량법보다 계산의 오버로드가 발생하지만 수학적으로 위치측정 오차 범위 계산 시 41%가 향상되었다.

The location measurement technique of moving worker in dangerous areas, is necessary for safety in the mines, basements, warehouses, etc. There are various measurement techniques about moving node of position in a restricted environment. Trigonometric Method, one of measurement techniques, is commonly used because of its easiness. However, errors occur frequently when measuring distance and position due to radio interference and physical disability with measuring instruments. This paper proposed a method which is more accurate and shows reduced margin of error than existing trigonometric method by recalculating distance between Anchor and moving node with various measuring instruments. By adding Anchor when calculating distance and position of moving node's estimated point, suggested technique obtains at least 41% efficiency compared to existing method.

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.

레이다는 표적에 대한 정보를 도출하기 위해 전파를 송신하고, 표적으로부터 반사된 신호를 수신하여 정보를 도출한다. 일반적인 레이다의 경우, 전파의 송수신 경로가 직선으로 가정하여 표적의 정보를 도출한다. 그러나 대기가 불안정한 환경에서는 대기 굴절률의 차이에 의한 전파의 굴절 현상이 발생한다. 전파의 굴절 현상에 의해 직선으로 가정 하였던 전파의 송수신 경로가 휘게 되고, 이를 기반으로 표적 정보를 추정할 때 표적 정보에 오차가 발생하게 된다. 특히 장거리 레이다의 경우 대기 굴절률에 의한 오차의 정도가 심하여 대기 굴절률에 의한 보정을 필요로 한다. 본 논문에서 는, 표적 정보를 추정하는 과정에서 대기 굴절률에 의한 전파 굴절 현상이 오차를 발생시키는 이유를 알아보고, 하나의 시나리오를 가정하여 표적의 거리, 각도, 속도(도플러)의 측면에서 오차를 분석하였다.

Radar detects target information by receiving signals that are reflected from target. Conventional radar assumes the tramsmitted and reception paths of signal are straight to derive target information. However, when atmospheric conditions are unstable, variation of atmospheric refractivity causes the transmitted/received signal paths to curve due to refraction. This curvature introduces errors in estimation of target information. Case of long range radar, errors due to atmospheric refractivity significantly affect radar performance so that compensation of atmospheric refractivity is needed. In this paper, we investigated how refracted path affects to radar performance and the errors induced by atmospheric refractivity in range, angle, velocity(doppler).

In many cases, the measurement error variances may be functions of the unknown true values or related covariates. This paper considers design-based estimators of the parameters of these variance functions based on the within-unit sample variances. This paper devotes to: (1) define an error scale factor $\delta$; (2) develop estimators of the parameters of the linear measurement error variance function of the true values under large-sample and small-error conditions; (3) use propensity methods to adjust survey weights to account for possible selection effects at the replicate level. The proposed methods are applied to medical examination data from the U.S. Third National Health and Nutrition Examination Survey (NHANES III).