Measurement Method Research Articles

An Optimized Design Method for Magnetometer Targeting High-Precision Measurement of Quasi-Periodic Magnetic Field Signal

An Optimized Design Method for Magnetometer Targeting High-Precision Measurement of Quasi-Periodic Magnetic Field Signal

A Novel Method for UV Measurement Using PLA-Based Photochromic Material and Machine Learning Models

A Novel Method for UV Measurement Using PLA-Based Photochromic Material and Machine Learning Models

Height Measurement Method for Meter-Wave Multiple Input Multiple Output Radar Based on Transmitted Signals and Receive Filter Design

To address the issue of low-elevation target height measurement in the Multiple Input Multiple Output (MIMO) radar, this paper proposes a height measurement method for meter-wave MIMO radar based on transmitted signals and receive filter design, integrating beamforming technology and cognitive processing methods. According to the characteristics of beamforming technology forming nulls at interference locations, we assume that the direct wave and reflected wave act as interference signals and hypothesize a direction for a hypothetical target. Then, the data received are processed to obtain the height of low-elevation-angle targets using a cognitive approach that jointly optimizes the transmitted signal and receive filter. Firstly, a signal model for the meter-wave MIMO radar based on the transmit weight matrix is established under low-elevation scenarios. Secondly, the signal model is analyzed and transformed. Thirdly, the beamforming algorithm that jointly optimizes the transmitted signals and receive filter is derived and analyzed. The algorithm maximizes the output Signal-to-Interference-plus-Noise ratio (SINR) of the receiver by designing the transmit weight matrix and receive filter. The optimization problem based on the SINR criterion is non-convex and difficult to solve. We transformed it into two sub-optimization problems and approximated the optimal solution through an alternating iteration algorithm. Finally, the proposed height measurement algorithm is compared with the Generalized Multiple Signal Classification (GMUSIC) and Maximum Likelihood (ML) height measurement algorithms. Simulation results show that the proposed algorithm can realize the height measurement of low-elevation targets. Compared to the GMUSIC and ML algorithms, it demonstrates superior performance in terms of computational complexity and multi-target elevation estimation.

Correction: A novel method for simultaneous measurement of 222Rn and 220Rn progeny concentrations measured by an alpha spectrometer

Correction: A novel method for simultaneous measurement of 222Rn and 220Rn progeny concentrations measured by an alpha spectrometer

Predictive Modeling for Electric Vehicle Battery State of Health: A Comprehensive Literature Review

The rising adoption of electric vehicles (EVs) utilizing lithium-ion batteries necessitates a robust understanding of state-of-health (SOH) estimation. The existing literature highlights various SOH estimation models, but a comprehensive comparative analysis is lacking. This paper addresses this gap by conducting an exhaustive review of diverse SOH estimation approaches for EV battery applications, including the direct measurement method, physical-based and data-driven approaches. Results highlight that data-driven methods, particularly those utilizing machine learning techniques, offer superior accuracy and adaptability but often require extensive datasets. In contrast, physical-based approaches provide interpretable insights but are computationally intensive, and direct measurement methods, though simple, lack generalizability. In addition, this paper also systematically reviews the indicators of battery SOH, influential factors affecting battery SOH, and various datasets used for SOH modeling. Future research should focus on integrating multiple modeling methodologies to leverage their combined strengths, enhancing the collection of comprehensive battery lifecycle datasets to support robust model development, and extending the scope of SOH estimation beyond individual cells to encompass entire battery packs.

Integrated Solution Combining Low-Frequency Forced Oscillation Technique and Continuous Equivital Sensor Monitoring for Assessment of Non-Invasive Ambulatory Respiratory Mechanics

Early assessment of respiratory mechanics is crucial for early-stage diagnosing and managing lung diseases, leading to greater patient outcomes. Traditional methods like spirometry are limited in continuous monitoring and patient compliance as they require forced maneuvers with significant patient cooperation, which may not be available in fragile individuals. The Forced Oscillation Technique (FOT) is a non-invasive measurement method, only based on the tidal breathing at rest from the patient for a limited time period. The proposed solution integrates low-frequency FOT with continuous monitoring using Equivital (EQV) sensors to enhance respiratory mechanics information with heart rate variability. Data were collected over a two-hour period from six healthy volunteers, measuring respiratory impedance every 7 min and continuously recording physiological parameters. The best-fitting fractional-order models for impedance data were identified using genetic algorithms. This study also explores the correlation between impedance model parameters and EQV data, discussing the potential of AI tools for forecasting respiratory properties. Our findings indicate that combined monitoring techniques and AI analysis provides additional complementary information, subsequently aiding the improved evaluation of respiratory function and tissue mechanics. The proposed protocol allows for ambulatory assessment and can be easily performed in normal breathing conditions.

Detection of Acromion Types in Shoulder Magnetic Resonance Image Examination with Developed Convolutional Neural Network and Textural-Based Content-Based Image Retrieval System

Background: The morphological type of the acromion may play a role in the etiopathogenesis of various pathologies, such as shoulder impingement syndrome and rotator cuff disorders. Therefore, it is important to determine the acromion’s morphological types accurately and quickly. In this study, it was aimed to detect the acromion shape, which is one of the etiological causes of chronic shoulder disorders that may cause a decrease in work capacity and quality of life, on shoulder MR images by developing a new model for image retrieval in Content-Based Image Retrieval (CBIR) systems. Methods: Image retrieval was performed in CBIR systems using Convolutional Neural Network (CNN) architectures and textural-based methods as the basis. Feature maps of the images were extracted to measure image similarities in the developed CBIR system. For feature map extraction, feature extraction was performed with Histogram of Gradient (HOG), Local Binary Pattern (LBP), Darknet53, and Densenet201 architectures, and the Minimum Redundancy Maximum Relevance (mRMR) feature selection method was used for feature selection. The feature maps obtained after the dimensionality reduction process were combined. The Euclidean distance and Peak Signal-to-Noise Ratio (PSNR) were used as similarity measurement methods. Image retrieval was performed using features obtained from CNN architectures and textural-based models to compare the performance of the proposed method. Results: The highest Average Precision (AP) value was reached in the PSNR similarity measurement method with 0.76 in the proposed model. Conclusions: The proposed model is promising for accurately and rapidly determining morphological types of the acromion, thus aiding in the diagnosis and understanding of chronic shoulder disorders.

Development of a non-invasive heart rate measurement method for sea turtles with dense keratinous scutes through effective electrode placement

Measuring the heart rate of sea turtles is important for understanding their physiological adaptations to the environment. Non-invasive methods to measure the electrocardiogram (ECG) of sea turtles have been developed by attaching electrodes to their carapace. However, this method has only been applicable to sea turtles with sparse keratin on their shell surfaces, such as loggerhead turtles, and it is difficult to detect heartbeats in sea turtles with dense keratinous scutes, including green sea turtles. Here, we explored the electrode placements on the plastron that can be applied to ECG measurement in green turtles. ECG signals were checked using a handheld ECG monitor at three sets of electrode placement on the plastron. When ECG signals could be detected, they were measured in the water tanks for several days to confirm the clarity of the ECG signals. Of the 29 green turtles, when the negative electrode was placed near the neck area of the plastron, clear ECG signals were obtained in nine individuals (39.1%), whereas ECG signals were not detected at any placements in four individuals (17.4%). Furthermore, in the water tank experiments, continuous ECG signals were successfully recorded by attaching a negative electrode near the neck: almost noiseless clear ECG signals even during moving in seven out of ten individuals and slightly weak and noisy signals in other individuals. The measured heart rate of ten individuals during resting was 8.6 ± 2.9 (means ± s.d.) beats min−1 and that during moving was 12.2 ± 4.7 beats min−1, similar to those reported in a previous study involving the insertion of electrodes inside the body. Therefore, for measuring the ECG of green turtles, the negative electrode should be placed closer to the neck, and the positive and earth electrodes should be placed to the lower left of the plastron. Although the selection of suitable individuals for measurements is required, this heart rate measurement method will contribute to a better understanding of the physiological status of sea turtles with dense keratinous scutes, including green turtles.

Usability Evaluation of Sistem Informasi Teknik Industri (SITI) Using Performance Measurement

Sistem Informasi Teknik Industri (SITI) is a web application developed by the Industrial Engineering Study Program, Kalimantan Institute of Technology, for interaction media between lecturers and students in Kerja Praktek (KP) and Tugas Akhir (TA). In the digital era, information systems play an important role in increasing efficiency and effectiveness in the field of education. This study aims to evaluate the usability of SITI using the Performance Measurement method, namely in the aspects of effectiveness and efficiency. The evaluation results showed that SITI had a very good level of effectiveness, with a task completion rate of 81.25% for lecturers and 81.82% for students. The average error rate reached 21.25% for lecturers and 9.95% for students, especially in the KP and TA guidance filling feature. However, the efficiency still needs to be improved, with a time-based efficiency of 0.09 goals/second for lecturers and 0.038 goals/second for students, as well as an overall relative efficiency of 67.03% for lecturers and 83.1% for students. SITI is effective in supporting academic interaction but needs improvements to features that have a high failure rate to improve efficiency and user experience.

Comparing Methods for Pyrite Surface Area Measurement Through Optical, Aqueous, and Gaseous Approaches

Accurate surface area data are imperative for the development of meaningful property–function relationships. Nitrogen gas (N2) adsorption/Brunauer–Emmet–Teller (BET) surface area analysis is a widely used technique for surface area characterization of materials because of straightforward sample preparation, automation, and low cost. However, iron disulfide (FeS2) does not typically exhibit quantifiable N2 monolayer formation in BET measurements. FeS2 has been applied in fields such as batteries, catalysis, and adsorption, all of which would benefit from techniques that reliably assess surface area (SSA) of the active material. To address this, we evaluated FeS2 samples by combining alternative surface characterization techniques to quantify SSA. Ten different FeS2 samples from various manufacturers are characterized via BET, laser diffraction, scanning electron microscopy, non-contact profilometry, and liquid dye adsorption. Compared to BET, which resulted in a wide range of SSAs between 0.049–1.213 m2 g−1, liquid dye adsorption was found to be accurate for pyrite samples at low sample masses (<50 mg), with SSA values between 0.99–10.20 m2 g−1. Using an optical characterization approach, which combined particle size and surface roughness data, we readily estimated SSA of the particles and found these values correlated linearly with liquid adsorption but not BET values. This work serves to help researchers choose a more fitting method for examining low surface area materials like FeS2 and can easily be applied to other minerals for quantitative and qualitative surface area comparisons.

Correlation between axial and coronal common bile duct diameters in computed tomography: a retrospective study of 1064 patients

BackgroundThe measurement of the common bile duct (CBD) diameter is essential for evaluating bile duct pathologies. The axial plane of computed tomography (CT) images is the established method for CBD diameter measurement. However, modern software enables easy reconstruction of axial CT images into the coronal plane, allowing for CBD diameter measurement in this plane. This study aimed to investigate the correlation between measurements in the axial and coronal planes.ResultsThe three reviewers demonstrated fair reliability in measuring CBD diameter in axial and coronal planes, with intraclass correlation coefficients of 0.776 and 0.799, respectively. A positive correlation was observed between the two diameters (r = 0.943), with 88.9% of axial diameter variation explained by coronal diameter and approximately 0.29 + (0.94 × coronal diameter) (R2 = 0.889, p < 0.001). When a cutoff value of 7 mm was used to predict an abnormal axial diameter, the agreement between axial and coronal CBD diameters was substantial (Kappa = 0.715) with discordance between the two measurements identified in 6.2% of cases (66/1064) when a) coronal diameter < 7 mm but axial measurement ≥ 7 mm (39/1064; 3.7%) and b) coronal diameter ≥ 7 mm but axial measurement < 7 mm (27/1064; 2.5%). In univariable linear regression and multivariable analyses, the strongest independent factors associated with increased axial CBD diameter were presence of focal CBD lesion, age ≥ 60 years, and cholecystectomy.ConclusionThere was a strong positive correlation between axial and coronal CBD diameters with substantial agreement when using a 7-mm cutoff and fair reliability in their measurements.

Validation of cantilever-enhanced photoacoustic particle-size-resolved light absorption measurement using nigrosin reference particles and Mie modelling

Abstract. Particle light absorption enhancement, also known as the lensing effect, is a complex phenomenon where particles undergo optical transformation as they age. This process is influenced by several factors, including particle size. To investigate the lensing effect, this study introduces and validates a novel method for size-resolved light absorption measurements using nigrosin particles as a model system. The method combines a three-wavelength cantilever-enhanced photoacoustic spectrometer (CEPAS) with a differential mobility analyser (DMA) to achieve particle-size-resolved measurements. Nigrosin, a well-characterised, spherically shaped, and water-soluble material, was selected to demonstrate the feasibility and precision of the approach. The system showed strong agreement (R2&gt;0.94) with Mie-modelled absorption, confirming its reliability. While the broader motivation for this work lies in advancing techniques for studying ageing, coating, and absorption enhancement in black carbon and other atmospheric aerosols, the present study serves as a foundational step by validating the methodology in a controlled and simplified context. Future studies will expand the application of this method to complex systems, including coated and aggregated black carbon particles, to explore phenomena such as absorption enhancement.

Novel RFID Multi-Label Network Location Measurement by Dual CCD and Non-Local Means–Harris Algorithm

To improve the performance of Radio Frequency Identification (RFID) multi-label systems, the multi-label network structure needs to be quickly located and optimized. A multi-label location measurement method based on the NLM–Harris algorithm is proposed in this paper. Firstly, multi-label geometric distribution images are obtained through a label image acquisition system of a multi-label semi-physical simulation platform with two vertical Charge-Coupled Device (CCD) cameras, and Gaussian noise is added to the image to simulate thermoelectric interference. Then, a fast NLM algorithm that optimizes the kernel coefficient acquisition speed is used for image denoising. Finally, the Harris corner algorithm is used to obtain the corner points of the images. After screening the diagonal points, the pixel coordinates of the preset origin and the four corners of the labels are obtained. Furthermore, the actual coordinates of the labels are obtained according to the pixel relationship. The results show that the average absolute errors of x, y, and z coordinates are 0.773 mm, 0.782 mm, and 0.807 mm, respectively. In addition, the relative errors are 1.659%, 2.260%, and 0.258%, which shows the high location accuracy of the multi-label network. It is of great significance to measure and optimize the performance of multi-label systems.

A laser tracking attitude dynamic measurement method based on real-time calibration and AEKF with a multi-factor influence analysis model

Abstract To address the limitations of six-degree-of-freedom (6-DOF) visual tracking systems in terms of low dynamic performance and the inability to perform measurements under light occlusion, this paper proposes a novel laser tracking attitude dynamic measurement method integrating vision and inertial measurement unit (IMU). A tailored real-time calibration model is developed to enable precise alignment of the vision and IMU coordinate systems during dynamic operations. To overcome the limitations of extended Kalman filter (EKF) that rely on static noise assumptions in complex dynamic measurement scenarios, this study proposes an adaptive mechanism based on multi-factor influence analysis. Through dynamic monitoring of visual observation noise, an adaptive EKF algorithm is designed to enhance performance under varying conditions. When integrated into a vision/IMU fusion system, the algorithm significantly enhances the system’s sensitivity to variations in visual sensor observation noise caused by changes in lighting and motion states. This capability allows rapid adjustment of filtering parameters, leading to substantial improvements in filtering accuracy and stability. Simulation results demonstrate that the proposed algorithm outperforms traditional EKF in fusion measurement accuracy when tested in simulated noise environments featuring sinusoidal and random jump signals. Furthermore, the fusion measurement accuracy is mainly influenced by the data density of the visual sensor and the measurement distance. Finally, the proposed method was validated on a precision turntable. Experimental results reveal that at a 3 m measurement distance and within a 0°–25° angular range, when the turntable rotates at a constant speed of 5°/s along a single axis, the maximum absolute deviation in repeatability of the fused attitude measurements was below 0.11°, and the system is capable of achieving a high measurement frequency of 100 Hz.

Assessment of Natural Radioactivity in a Residence in Belo Horizonte

Natural radioactivity comes from natural radionuclides present in rocks and soil and from cosmic rays. In addition to gamma-emitting radionuclides, radon stands out, which is a carcinogenic gas. In nature, radon occurs as radioisotopes: 222Rn (half-life time, t1/2,of 3.83 d), 219Rn (t1/2 = 3.92 s) and 220Rn (or thoron, t1/2 = 54.5 s). The World Health Organization (OMS) recommends that it be measured in homes, with the recommended limit being 100 Bq/m3 and the maximum limit being 300 Bq/m3. This work evaluates the origin of natural radiation in a residence in Belo Horizonte, Minas Gerais, Brazil, in which was observed radon concentrations above the limits established by the OMS. The detectors used were: nuclear trace detectors type CR-39, electrets (E-PERM), AlphaGUARD (AG) and the detector RS-230. The result of the 222Rn concentration measured in the electrets in the rooms of the residence varied from 14,8 Bq/m3 to 932 Bq/m3. At this highest point, the result of the average concentration of AlphaGUARD was from 4.78 kB/m3, with a maximum value of 8.5 kBq/m3. The concentration of 220Rn varied Bq/m3 Bq/m3. As this is a basement-type room, the bedroom next door was investigated, in which it is highlighted that the radon concentration of the detector CR-39 was from 445 Bq/m3, AG of 198.2 Bq/m3 with a maximum value of 350 Bq/m3, and electret of 29.6 Bq/m3. Gamma scanning with the RS-230 indicates higher counts on uncoated walls. Measurements of radon in the water showed background concentrations. It is concluded that poor ventilation of the location must be the biggest contributor to the high concentration of 222Rn, which originates mainly from the soil. The thoron concentration was higher in construction materials due to the measurement method. The instrumentation used allows a complete and comparative study between detectors in order to find the origin of natural radionuclides and subsequently suggest appropriate mitigation measures. In future studies, radon concentration in the soil and radon progeny will be measured.

Real-time dose measurement in minibeam radiotherapy using radioluminescence imaging.

Minibeam radiotherapy (MBRT) uses small parallel beams of radiation to create a highly modulated dose pattern. The aim of this study is to develop an optical radioluminescence imaging (RLI) approach to perform real-time dose measurement for MBRT. MBRT was delivered using an image-guided small animal irradiator equipped with a custom collimator. Five slabs of plastic scintillators with a thicknesses of 0.5, 1, 2, 3 and 10 mm were placed on top of a mouse phantom, to localize and measure the delivered dose. A thin radioluminescence film (Gd2O2S:Tb) was used to obtain the mini beam dose profile that was compared against GafChromic (GC) films measurements. The RLI signal was detected with a CMOS camera placed at 90 deg with respect to the beam axis. Monte Carlo (MC) simulations were also performed using TOPAS for comparison with the experimental results. The measured peak to valley dose ratio (PVDR) obtained with RLI was 16.7 in line with GC films measurements. The differences between peak and valley dimension were less that 3% with respect to GC measurements. Using RLI performed with the scintillator slabs, it was possible to localize and measure in real-time MBRT delivery on the mouse phantom. We proposed a novel method for MBRT dose localization and measurement in real-time based on RLI. The results we obtained are in good agreement with GC film measurements.

Comparison of the Modified CTOD Measurement Method with the Double Clip Gauge Method in a Compact Tension Specimen

For allowable defect analyses, the fracture toughness of materials needs to be accurately predicted. In this regard, a lower fluctuation of fracture toughness can lead to reduction in safety and economic risks. Crack tip opening displacement (CTOD), which is the representative parameter for fracture toughness, can be measured by various methods, such as the δ5, the J-conversion method, the single clip gauge method, and the double clip gauge method. When calculating CTOD from test results, the principle of similar triangles, which adopts the plastic hinge model, is influenced by the rotation factor, rp. Therefore, in order to reduce the fluctuation of CTOD, the exact value of rp must be defined. This study investigates various methods to predict fracture toughness in metallic materials, and assess the pros and cons of each method. Moreover, the equation of rp is modified by using a double clip gauge in compact tension (CT) to reduce the fluctuation of CTOD. The rp value is derived from 0.55 to 0.68, using the double clip gauge method. Finite element analysis is used to derive the rp values, which range from 0.50 to 0.66, in order to verify the validity of the derived rp values. This ensures the validity of the rp value derived from the experiment. In addition, the fluctuation of CTOD, based on the modified equation of rp, is lower than that using the single clip gauge method, according to BS 7448.

Simple method for the direct measurement of cohesive forces between microscopic particles.

We present a simple and inexpensive method for measuring weak cohesive interactions. This technique is applied to the specific case of oil droplets with a depletion interaction, dispersed in an aqueous solution. The experimental setup involves creating a short string of droplets while immobilizing a single droplet. The droplets are held together via depletion interactions, and a single cohesive bond holds together nearest neighbours. Initially, the buoyant droplets are held in a flat horizontal chamber. The droplets float to the top of the chamber and are in contact with a flat glass interface. In the horizontal configuration, there is no component of the effective buoyant force acting in the plane of the chamber. The angle of the chamber is gradually increased, and the effective buoyant force acting on the string of droplets slowly increases. At a critical point, when the combination of gravity and buoyancy is equal to the cohesive force, the droplet string will detach from the immobile droplet. Our method allows for a simple direct measurement of cohesive forces on the tens of pico-Newton scale. To illustrate the validity of this technique, the droplet radii and concentration of depletant are varied, and their impact on the cohesive force is measured. This method offers a simple, accessible, and reproducible means of exploring cohesive interactions beyond the specific case of oil droplets and a depletion interaction.

Evaluation of renal elasticity by shear wave elastography in children with Familial Mediterranean Fever.

Familial Mediterranean Fever (FMF) is a genetic disorder that can cause kidney damage. Shear wave elastography (SWE), a non-invasive method, was used to evaluate the decrease in renal tissue elasticity as a predictive parameter for amyloidosis. This study aimed to examine the changes in renal elasticity in patients with FMF using the renal SWE measurement method. The present study included 50 pediatric patients diagnosed with FMF. The median SWE values of both kidneys were compared between the groups. Acute phase reactants were also evaluated. The SWE measurements (for the left kidney p = 0.007, for the right kidney p = 0.06) and proteinuria levels (p < 0.001) of the patient group were found to be higher than those of the control group. No correlation was observed between the disease activity score and the SWE measurements. Erythrocyte sedimentation rate (p < 0.001), C-reactive protein (p < 0.001) and urine protein/creatinine ratio (p < 0.001) were significantly higher in the remission period compared to the control group, whereas estimated glomerular filtration rate was found to be low in the patient group (p < 0.001), which was considered as an indicator that subclinical inflammation continued in the course of the disease. The acute phase reactants were elevated in patients with FMF even in the remission period which indicates that the disease is constantly active and have the potential to cause damage in all organs and tissues. It is thought that this subclinical inflammation may also contribute to increased tissue stiffness, which may serve as a predictor for the development of amyloidosis.

Harmonization of alcohol use data and mortality across a multi-national HIV cohort collaboration.

Alcohol use is measured in diverse ways across settings. Harmonization of measures is necessary to assess effects of alcohol use in multi-cohort collaborations, such as studies of people with HIV (PWH). Data were combined from 14 HIV cohort studies (nine European, five North American) participating in the Antiretroviral Therapy Cohort Collaboration. We analyzed data on adult PWH with measured alcohol use at any time from 6 months before starting antiretroviral therapy. Five cohorts measured alcohol use with AUDIT-C and others used cohort-specific measures. We harmonized alcohol use as grams/day, calculated using country-level definitions of a standard drink. For Alcohol Use Disorders Identification Test (AUDIT-C), we used Items 1 (frequency) and 2 (number of drinks on a typical day). Where alcohol was measured in categories, we used the mid-point to calculate grams/day. We used multivariable Cox models to estimate associations of alcohol use with mortality. Alcohol use data were available for 83,424 PWH, 22,447 (27%) had AUDIT-C measures and 60,977 (73%) recorded the number of drinks/units per week/day. Of the sample, 19,150 (23%) were female, 54,006 (65%) had White ethnicity, and median age was 42 years. Median alcohol use was 0.3 g/day (interquartile range [IQR] 0-4.8) and 0 g/day (IQR 0-20) for those with and without AUDIT-C. There was a J-shaped relationship between grams/day and mortality, with higher mortality for PWH reporting no alcohol use (adjusted hazard ratio [aHR] 1.46; 95% CI: 1.23-1.72) and heavier (>61.0 g/day) alcohol use (aHR 1.92; 1.41-2.59) compared with 0.1-5.5 g/day among those with AUDIT-C measures. Associations were similar among those with non-AUDIT-C measures. Grams/day is a useful metric to harmonize diverse measures of alcohol use. Magnitudes of associations of alcohol use with mortality may differ by setting and measurement method. Higher mortality among those with heavier alcohol use strengthens the case for interventions to reduce drinking.