Minimize Measurement Error Research Articles

Assessing the Reliability of the CAMS Rating Scale Using aGeneralizability Study.

Background: An important consideration when conducting randomized controlled trials is treatment differentiation. Direct observation helps ensure that providers in different treatment groups are delivering distinct interventions. One direct observation method is the use of a measure to rate clinician performance when delivering an intervention. Aims: This generalizability study evaluated the reliability of the CAMS Rating Scale (CRS), a measure used to assess delivery of the Collaborative Assessment and Management of Suicidality (CAMS). Method: Digitally recorded tapes of clinicians delivering either CAMS or Enhanced Care-As-Usual (E-CAU) were coded using the CRS. Sessions (N=36) were each coded by two raters, and encompassed four clinicians, four time points, and 34 unique patients across two treatment groups. A reliability coefficient (i.e., G coefficient) and the percentages of variance contributed by each component of the measurement model were obtained. Results: The CRS reliably differentiates CAMS from E-CAU, minimizes measurement error relative to expected variance sources, and continues to demonstrate high inter-rater reliability. Limitations: The absence of blind raters, a formal training protocol for the rating team, and ratings from all clinician-patient dyads at all time points was a limitation. Conclusion: The CRS is a reliable treatment differentiation measure that can play an integral role in studies evaluating CAMS.

Minimizing Measurement Error of Phase Noise of a Narrow-Band Laser Using a Fiber-Based Mach–Zehnder Interferometer with Polarization Maintenance

A device for measurements of phase noise with the use of the Mach–Zehnder interferometer is proposed, in which all fi ber components are made based on fiber with polarization state maintenance. This permits not using a basic radiation source in the device, and thereby reducing significantly the installation cost. Two interference signals from orthogonally polarized waves are formed in the device and are then divided by a polarizing demultiplexor that eliminates the effect of external noise on the measurement result. An algorithm for calculating phase noise is described and an estimate of the effect of temperature instability is presented. A comparison of the characteristics of phase noise between calculated and specified in modeling was performed in order to assess the operational capability of the installation and algorithm for signal processing.

The frontal skull Hounsfield unit value can predict ventricular enlargement in patients with subarachnoid haemorrhage

Hydrocephalus is a common complication following subarachnoid haemorrhage (SAH) arising from spontaneous aneurysm rupture. The Hounsfield unit (HU) value from computed tomography scans may reflect bone mineral density, which correlates with body mass index, which in turn is related to post-SAH ventricle size changes. We herein investigated potential associations between frontal skull HU values and ventricle size changes after SAH. HU values from four different areas in the frontal bone were averaged to minimize measurement errors. The bicaudate index and Evans ratio were measured using both baseline and follow-up CT images. CT images with bicaudate index >0.2 and Evans ratio >0.3 simultaneously were defined as indicating ventriculomegaly. We included 232 consecutive patients with SAH due to primary spontaneous aneurysm rupture, who underwent clipping over almost a 9-year period at a single institution. The first tertile of frontal skull HU values in older patients (≥55 years) was an independent predictor of ventriculomegaly after SAH, as compared to the third tertile in younger patients (hazard ratio, 4.01; 95% confidence interval 1.21–13.30; p = 0.023). The lower frontal skull HU value independently predicted ventricular enlargement post-SAH, due to the potential weak integrity of subarachnoid trabecular structures in younger patients.

An Ergonomic Testing System for the First Metatarsophalangeal Joint Stiffness.

Osteoarthritis sufferers commonly have first metatarsophalangeal joint (MTPJ) problems in which articular surfaces are changed permanently due to fatigue. Therefore, medical devices for early diagnosis would increase the opportunity for prevention of disease progression. In previous studies on stiffness of the first MTPJ many details, although functionally of great importance, have not been fully considered including: design and size of the device, tribology consideration, and errors from device. Therefore, the motivation of our research was to enhance the device design by reducing the size of the device, and device design was enhanced by minimizing measurement errors through development of a new ergonomic left and right foot instrument located medial to the first MTPJ (instead of beneath the foot). The first MTPJ stiffness (N mm/kg radian) measurement was taken on 28 subjects with two replicates per subject by the same tester. The first MTPJ stiffness ranged from 3.49 to 14.42 N mm/kg radian with the mean (SD) value of 8.28 (3.15) N mm/kg radian for the left feet and 3.91 to 11.90 N mm/kg radian with the mean (SD) value of 7.65 (2.07) N mm/kg radian for the right feet. Reliability evaluation was measured using intraclass correlation coefficient and described an excellent reliability between two tests.

Ultrasonic Based Device to Monitor Oil Separation from Oily Water Discharges

AbstractDischarges of oily water are common among a number of commercial operations. If unregulated these effluents can lead to both short and long term adverse environmental impacts. Development efforts were undertaken in this study for a robust ultrasonic based device to monitor separation of oil and water from oily water effluents. Most of these separations are carried out in gravity settlers where several problems are encountered. These include periodic temperature variations (often over a 25–50 °C range), changes in composition of the oily phase, and presence of suspended impurities as well as fouling conditions. The device incorporates an innovative low cost self‐correction feature to minimize measurement errors under such difficult and dynamic conditions. This feature allows continuous in‐situ measurement of acoustic velocity, a key parameter required for oil depth measurements, giving accuracy within ±2 %. The development plans moved progressively from proof‐of‐concept to prototype of the device with a systematic strategy to improve reliability and accuracy at each stage. These included selection of appropriate transducer frequency and tests with suspended and settled impurities. After initial evaluations, a device configuration with a transducer mounted on a guided float was recommended for further development efforts. The transducer was placed facing down at the centre of the float designed to move up and down with the liquid level in the tank.

Impact of Exercise-Induced Muscle Damage on Performance Test Outcomes in Elite Female Basketball Players.

Doma, K, Leicht, A, Sinclair, W, Schumann, M, Damas, F, Burt, D, and Woods, C. Impact of exercise-induced muscle damage on performance test outcomes in elite female basketball players. J Strength Cond Res 32(6): 1731-1738, 2018-The purpose of this study was 2-fold: first, to examine the impact of exercise-induced muscle damage (EIMD) on physical fitness qualities after a basketball-specific training session; second, to determine the reproducibility of the sport-specific performance measures in elite female basketball players. Ten elite female basketball players (age 25.6 ± 4.5 years; height 1.8 ± 0.7 m; and body mass 76.7 ± 8.3 kg) undertook a 90-minute training session involving repeated jumping, sprinting, and game-simulated training. Indirect muscle damage markers (i.e., countermovement jump, delayed onset of muscle soreness [DOMS], and creatine kinase [CK]) and sport-specific performances (i.e., change-of-direction [COD] test and suicide test [ST]) were measured before and 24 hours after training. These measures were also collected 1 week after training to determine the reproducibility of the basketball-specific performance measures. A significant reduction in lower-body power (-3.5 ± 3.6%; p ≤ 0.05), while a significant increase in DOMS (46.7 ± 26.3%; p ≤ 0.05) and CK (57.6 ± 23.1%; p ≤ 0.05) was observed 24 hours after exercise. The ST was also significantly increased (2.1 ± 1.8%; p ≤ 0.05), although no difference was observed for COD (0.1 ± 2.0%; p > 0.05). The intraclass correlation coefficient and coefficient of variation for the COD and ST were 0.81 and 0.90, respectively, and 1.9 and 1.5%, respectively. In conclusion, appropriate recovery should be considered the day after basketball-specific training sessions in elite basketball players. Furthermore, this study showed the usability of performance measures to detect changes during periods of EIMD, with acceptable reproducibility and minimal measurement error.

Relative gravimeter prototype based on micro electro mechanical system

This research to make gravity measurement system by utilizing micro electro mechanical system based sensor in Gal order. System design consists of three parts, design of hardware, software, and interface. The design of the hardware include of designing the sensor design to measure the value of a stable gravity acceleration. The ADXL345 and ADXL335 sensors are tuned to obtain stable measurements. The design of the instrumentation system the next stage by creating a design to integrate between the sensor, microcontroller, and GPS. The design of programming algorithm is done with Arduino IDE software. The interface design uses a 20x4 LCD display to display the gravity acceleration value and store data on the storage media. The system uses a box made of iron and plate leveling to minimize measurement errors. The sensor test shows the ADXL345 sensor has a more stable value. The system is examined by comparing with gravity measurement of gravimeter A-10 results in Bandung observation post. The result of system test resulted the average of system correction value equal to 0.19 Gal. The system is expected to use for mineral exploration, water supply analyze, and earthquake precursor.

Resonance Effect Decrease and Accuracy Increase of Piezoelectric Accelerometer Measurement by Appropriate Choice of Frequency Range

A suitable piezoelectric accelerometer mathematical model is proposed to extract a relationship of motion relative frequency as a function of natural frequency. This relationship helps to select appropriate accelerometer frequency range that minimizes measurement error and improves accuracy. It also allows deducing a formula relating the damping rate and the measurement error of the accelerometer. To protect the accelerometer from failure, the resonance phenomenon effect must be minimized. In order to achieve this objective, physical principle is modeled to find a precise relationship which can determine the accelerometer appropriate frequency range. The developed model was simulated and the obtained results have showed that the selection of the frequency range has minimized the measurement error, increased the accelerometer accuracy, and reduced the resonance effect. Finally a comparative study was conducted to show the importance of the obtained results compared to recent literatures.

Minimal important change, measurement error and responsiveness for the SEFAS

Minimal important change, measurement error and responsiveness for the SEFAS

Use of units of measurement error in anthropometric comparisons.

Anthropometrists attempt to minimise measurement errors, however, errors cannot be eliminated entirely. Currently, measurement errors are simply reported. Measurement errors should be included into analyses of anthropometric data. This study proposes a method which incorporates measurement errors into reported values, replacing metric units with 'units of technical error of measurement (TEM)' by applying these to forensics, industrial anthropometry and biological variation. The USA armed forces anthropometric survey (ANSUR) contains 132 anthropometric dimensions of 3982 individuals. Concepts of duplication and Euclidean distance calculations were applied to the forensic-style identification of individuals in this survey. The National Size and Shape Survey of Australia contains 65 anthropometric measurements of 1265 women. This sample was used to show how a woman's body measurements expressed in TEM could be 'matched' to standard clothing sizes. Euclidean distances show that two sets of repeated anthropometric measurements of the same person cannot be matched (> 0) on measurements expressed in millimetres but can in units of TEM (= 0). Only 81 women can fit into any standard clothing size when matched using centimetres, with units of TEM, 1944 women fit. The proposed method can be applied to all fields that use anthropometry. Units of TEM are considered a more reliable unit of measurement for comparisons.

Lnvestigation of β-Emission Methods of Monitoring Coolant Water Level in Nuclear Power Plants

This investigation was performed on a vessel heat-engineering bench. The working medium was water under pressure up to it 20.5 MPa and temperature from 20 (cold) to 350°C (hot). The controllers were a β-emission sensor of level and a Sapfir-22DD differential manometer as the standard. The objective was to determine the characteristics of a β-emission sensor under the conditions of the working medium. Analysis of the experimental data showed that the indications of the β-emission sensor and differential manometer were identical and linear as a function of the level of both the cold and hot water. The characteristics of the β-emission sensor are: minimal response time and measurement error, very small dimensions, serviceability at pressures to 20.5 MPa and temperature to 350°C, at least 10 years life, and energy independence of the primary converter.

Errors in the measurement of transmission loss in a standing wave tube

The four-microphone method of the standing wave tube can be used to effectively measure the transmission loss (TL) of acoustic materials. However, large errors in the measurement results may be observed at specific frequencies. To investigate the mechanism and lower the error, in this paper, experiments are conducted with a standing wave tube, fabricated for these experiments, using a four-microphone method. Specific factor analysis for the error is carried out. Three structure parameters of the standing wave tube are varied to minimize measurement errors. A finite element method (FEM) is employed to calculate the internal sound field distribution and TL in the standing wave tube. Based on the comparison between the experiments and the calculations, the orthogonal experimental design (OED) is performed to optimize the three structure parameters and improve the measurement accuracy to reduce the error in testing TL. The result of this work can be used as a reference for the measurement of acoustic material, which can benefit the noise control community.

Tracking a single pigeon using a shadowing filter algorithm.

Miniature GPS devices now allow for measurement of the movement of animals in real time and provide high‐ quality and high‐resolution data. While these new data sets are a great improvement, one still encounters some measurement errors as well as device failures. Moreover, these devices only measure position and require further reconstruction techniques to extract the full dynamical state space with the velocity and acceleration. Direct differentiation of position is generally not adequate. We report on the successful implementation of a shadowing filter algorithm that (1) minimizes measurement errors and (2) reconstructs at the same time the full phase‐space from a position recording of a flying pigeon. This filter is based on a very simple assumption that the pigeon's dynamics are Newtonian. We explore not only how to choose the filter's parameters but also demonstrate its improvements over other techniques and give minimum data requirements. In contrast to competing filters, the shadowing filter's approach has not been widely implemented for practical problems. This article addresses these practicalities and provides a prototype for such application.

Inter-rater and inter-instrument reliability of goniometric thumb active and passive flexion range of motion measurements in healthy hands

Introduction Goniometry is a common measure of range of motion and may be assessed by different therapists and goniometers. To date, there is limited psychometric data on active and passive range of motion measurements of individual thumb joints. The purpose of this study was to analyze inter-rater and inter-instrument reliability of passive and active flexion goniometric measures of thumb joints in healthy adults. Methods A within-subjects psychometric design was utilized. Two raters each used two goniometers (Baseline™ Flexion-Hyper Extension and Baseline™ 180 Degree Digit) to measure each participant’s (n = 48) thumb carpometacarpal, metacarpophalangeal, and interphalangeal flexion range of motion. Inter-rater and inter-instrument reliability and stability were evaluated through use of intraclass correlation coefficient, standard error of the measurement, and minimal detectable change test statistics. Results Inter-rater reliability was poor for carpometacarpal flexion and good-to-excellent for metacarpophalangeal and IP flexion. Between-rater error ranged between 3.9 and 6.3 degrees for active measurements and between 3.9 and 7.9 degrees for passive. Error was generally less when using the Baseline™ 180 Degree Digit goniometer. Inter-instrument reliability was excellent for all joints. Discussion These findings validate the concerns that thumb goniometry inter-rater reliability may differ in clinical and non-clinical populations, support further study in clinical populations, and support a common assumption that the same rater should test the same client with the same goniometer to minimize measurement error. When compared to the Baseline™ Flexion-Hyper Extension Goniometer, the Baseline™ 180 Degree Digit had higher repeatability across raters. Further research on within-rater reliability is required as is study on clinical populations.

Skeletal muscle analyses: agreement between non‐contrast and contrast CT scan measurements of skeletal muscle area and mean muscle attenuation

Low skeletal muscle area (SMA) and muscle radiation attenuation (MRA) have been associated with poor prognosis in various patient populations. Both non-contrast and contrast CT scans are used to determine SMA and MRA. The effect of the use of a contrast agent on SMA and MRA is unknown. Therefore, we investigated agreement between these two scan options. SMA and MRA of 41 healthy individuals were analysed on a paired non-contrast and contrast single CT scan, and agreement between paired scan results was assessed with use of Bland-Altman plots, intraclass correlation coefficients (ICCs), standard error of measurements (SEM) and smallest detectable differences at a 95% confidence level (SDD95 ). Analyses were stratified by tube voltage. Difference in SMA between non-contrast and contrast scans made with a different tube voltage was 7·0±7·5cm2 ; for scans made with the same tube voltage this was 2·3±1·7cm2 . Agreement was excellent for both methods: ICC: 0·952, SEM: 7·2cm2 , SDD95 : 19·9cm2 and ICC: 0·997, SEM: 2·0cm2 , SDD95 : 5·6cm2 , respectively. MRA of scans made with a different tube voltage differed 1·3±11·3 HU, and agreement was poor (ICC: 0·207, SEM: 7·9 HU, SDD95 : 21·8 HU). For scans made with the same tube voltage the difference was 6·7±3·2 HU, and agreement was good (ICC: 0·682, SEM: 5·3 HU, SDD95 : 14·6 HU). In conclusion, SMA and MRA can be slightly influenced by the use of contrast agent. To minimise measurement error, image acquisition parameters of the scans should be similar.

Multi-parameter improvement method for (micro-) structural properties of high performance ceramics

Many pH-measurement electrodes rely on porous diaphragms to create a liquid electrolyte junction between reference-electrolyte and the fluid to be measured. In field applications, the diaphragm is required to meet partly contradictory improvement criteria. To minimize measurement errors and to ensure durability of the measurement device, the diaphragm is supposed to maximize electrolyte conductivity and reference-electrolyte outflow velocity, while simultaneously minimizing reference electrolyte flow rate. The task of optimizing the overall performance of this small piece of ceramics has lead to the development of a novel multi-parameter improvement scheme for its (micro-) structural design. The method encompasses the consideration of microscopic material design parameters, such as porosity, pore- tortuosity and constrictivity, macroscopic material parameters such as diaphragm diameter and length, as well as process parameters like internal electrode pressure or the electrolyte viscosity and specific resistivity. Comprising sets of design parameters to dimensionless groups, concrete design guidelines as well as the introduction of a three-dimensional improvement space concept are proposed. The novel design space concept allows the improvement of each possible diaphragm-based measurement set-up, by considering the simultaneous, dimensionless interaction of all relevant design parameters.

Residual stress analysis in linear friction welded in-service Inconel 718 superalloy via neutron diffraction and contour method approaches

In this study, an analysis of elastic residual stress in Inconel® 718 (IN 718) linear friction welds (LFWs) was carried out. In particular, the suitability of LFW for manufacturing and repair of aero engine components was emulated by joining virgin and in-service (extracted from a turbine disk) materials. The evolution in the residual strains and stresses in the heat-affected zone (HAZ), thermomechanically affected zone (TMAZ) and dynamically recrystallized zone (DRX) of the weld was characterized using the neutron diffraction and contour methods.The results provided insight into diverse challenges in quantitative analysis of residual stresses in welded IN 718 using diffraction techniques. Specifically, judicious selection of the beam width, height and stress-free lattice spacing were seen to be crucial to minimize measurement error and increase accuracy. Further, the contour method – a destructive technique relying on capturing the stress relaxation after electrical discharge machining – was used to characterize the residual stress distribution on two-dimensional plane sections of the welds. Both techniques suggested an increasing magnitude of residual stress originating from the base metal that reached a peak at the weld interface. Both methods indicated that the peak magnitude of residual stresses were below the yield stress of IN 718.

Signal conditioning of thermocouple using intelligent technique

This paper implies using a neural network based technique for dispensation of a thermocouple signal [1]. At the stage of linearization, the thermocouple cold junction compensation and sensor transfer curve are in the same stride. For sensing the reference junction temperature a thermistor has been used and whose temperature tables are taken into consideration [2][3]. A multilayered Artificial Neural Network (ANN) has been trained using Levendberg-Marquadt algorithm [4]. For initializing the biases and weight of the ANN, to minimize measurement errors, and linearize the thermocouple by simulation methods this algorithm is as well very constructive [4]. Data of thermocouple for different material types may approach from the standard tables and must be interpolated for any readings not directly contained in these tables. The fluctuation in the hotness of the reference junction of the thermocouple have an effect on the repeatability of the thermocouple hence the reaction of the thermocouple is studied at different ambient temperatures from 0-45°C and the error due to increase in this temperature is also minimized simultaneously. As training of data increases the network becomes more capable of reducing the error close to zero. So a new technique is utilized which trains the data more and more along with increasing temperature leading to less errors than conventional or previous instances of the same program[5].

Precise Non-Intrusive Real-Time Gaze Tracking System for Embedded Setups

This paper describes a non-intrusive real-time gaze detection system, characterized by a precise determination of a subject's pupil centre. A narrow field-of-view camera (NFV), focused on one of the subject's eyes follows the head movements in order to keep the pupil centred in the image. When a tracking error is observed, feedback provided by a second camera, in this case a wide field-of-view (WFV) camera, allows quick recovery of the tracking process. Illumination is provided by four infrared LED blocks synchronised with the electronic shutter of the eye camera. The characteristic shape of corneal glints produced by these illuminators allows optimizing the image processing algorithms for gaze detection developed for this system. The illumination power used in this system has been limited to well below maximum recommended levels. After an initial calibration procedure, the line of gaze is determined starting from the vector defined by the pupil centre and a valid glint. The glints are validated using the iris outline to avoid glint distortion produced by changes in the curvature on the ocular globe. In order to minimize measurement error in the pupil-glint vector, algorithms are proposed to determine the pupil centre at sub-pixel resolution. Although the paper describes a desk-mounted prototype, the final implementation is to be installed on board of a conventional car as an embedded system to determine the line of gaze of the driver.

형성층 전기저항을 이용한 조경용 수목 활력도 분석

수목의 활력도는 다양한 방법으로 측정한다. 수목의 형성층 전기저항은 전기생리학적 진단 방법을 이용하여 수목의 활력도를 간접적으로 나타낸다. 본 연구는 Shigometer를 이용하여 몇 가지 수목의 활력도를 측정하고 수종 간 차이를 비교하고자 하였다. 그리고 개엽 시기, 방위, 수피 온도 등 전기저항 값에 영향을 주는 요인들을 파악하고자 하였다. 측정용 탐침의 길이를 일정하게 유지하여 측정오차를 최소화하였다. 대상 수종은 성균관대학교 자연과학캠퍼스에 있는 30-40년생 느티나무, 은행나무, 메타세쿼이아, 잣나무 및 튜울립나무로 하였고 각 종당 3개체를 선정하였다. 측정 시기는 2011년 3월부터 5월까지, 지면으로부터 60 cm와 흉고높이인 1.2 m에서 동서남북 4개 방위 별로 전기저항 값을 측정하였다. 수목 부근의 토양환경과 식물의 스트레스 반응을 함께 측정하였다. 측정 결과를 바탕으로 전기저항과 영향 요인과의 상관관계를 살펴보았다. 개엽 시기 이전인 3월 중순까지는 대체적으로 전기저항 값이 높았으나 4월부터 점차 낮아지기 시작하여 5월 11일에는 가장 낮은 값을 보였다. 전기저항 값의 시기별 변화는 토양수분, 토양전도도, 토양온도, 수목의 스트레스 반응과 비슷한 경향을 보였다. 잣나무의 경우 겨울에도 잎이 떨어지지 않아 측정 기간 동안 전기저항 값의 변화는 크기 않았다. 느티나무, 은행나무 및 메타세쿼이아는 남쪽 방향의 수피 온도가 다른 방위에 비하여 높았으며 전기저항 값은 가장 낮았다. Shigometer는 수목의 활력도를 현장에서 간단하게 측정함으로써 수목 관리에 유용하게 이용할 수 있을 것으로 생각된다. There are various methods to evaluate tree vigor. Cambial electrical resistance represents tree vigor using the method of electrophysiological diagnosis. This study investigated the vigor of several tree species using Shigometer, and compared the differences among the species. The factors, such as foliation, trunk orientation and bark temperature, which affect electrical resistance were also investigated. The needle penetration into cambium was controlled to keep the depth consistent in order to minimize measurement error. Each of three trees were selected from Zelkova serrata, Ginkgo biloba, Metasequoia glyptostroboides, Pinus koraiensis, and Liriodendron tulipifera. The electrical resistances were measured at 60 and 120 cm height of the stem in 4 directions from March until May 2011. The soil conditions in surrounding areas and tree stress responses were also measured. The results were analyzed for the relationship between electrical resistance and the affecting factors. The electrical resistance showed a relatively higher level before foliation until mid-March. The values started to decline from April and recorded a minimal level on May 11. The changes of soil moisture, soil electric conductivity, and tree stress responses during the measurement period showed a similar trend to that of electrical resistance. The Pinus koraiensis, an evergreen conifer, showed few changes on the electrical resistance values during the measurement period. Zelkova serrata, Ginkgo biloba, and Metasequoia glyptostroboides showed the highest bark temperatures and lowest electrical resistances at their south-facing stem. Shigometer can provide measures simple to assess tree vigor in the fields, and to the management of trees.