-
Scientific Reports May 2022Physical unclonable functions (PUF) are cryptographic primitives employed to generate true and intrinsic randomness which is critical for cryptographic and secure...
Physical unclonable functions (PUF) are cryptographic primitives employed to generate true and intrinsic randomness which is critical for cryptographic and secure applications. Thus, the PUF output (response) has properties that can be utilized in building a true random number generator (TRNG) for security applications. The most popular PUF architectures are transistor-based and they focus on exploiting the uncontrollable process variations in conventional CMOS fabrication technology. Recent development in emerging technology such as memristor-based models provides an opportunity to achieve a robust and lightweight PUF architecture. Memristor-based PUF has proven to be more resilient to attacks such as hardware reverse engineering attacks. In this paper, we design a lightweight and low-cost memristor PUF and verify it against cryptographic randomness tests achieving a unique, reliable, irreversible random sequence output. The current research demonstrates the architecture of a low-cost, high endurance Cu/HfO[Formula: see text]Si memristor-based PUF (MR-PUF) which is compatible with advanced CMOS technologies. This paper explores the 15 NIST cryptographic randomness tests that have been applied to our Cu/HfO[Formula: see text]Si MR-PUF. Moreover, security properties such as uniformity, uniqueness, and repeatability of our MR-PUF have been tested in this paper and validated. Additionally, this paper explores the applicability of our MR-PUF on block ciphers to improve the randomness achieved within the encryption process. Our MR-PUF has been used on block ciphers to construct a TRNG cipher block that successfully passed the NIST tests. Additionally, this paper investigated MR-PUF within a new authenticated key exchange and mutual authentication protocol between the head-end system (HES) and smart meters (SM)s in an advanced metering infrastructure (AMI) for smartgrids. The authenticated key exchange protocol utilized within the AMI was verified in this paper to meet the essential security when it comes to randomness by successfully passing the NIST tests without a post-processing algorithm.
PubMed: 35606367
DOI: 10.1038/s41598-022-11240-6 -
Sensors (Basel, Switzerland) Apr 2023This paper addresses the current challenges in cybersecurity of smart metering infrastructure, specifically in relation to the Czech Decree 359/2020 and the DLMS...
This paper addresses the current challenges in cybersecurity of smart metering infrastructure, specifically in relation to the Czech Decree 359/2020 and the DLMS security suite (device language message specification). The authors present a novel testing methodology for verifying cybersecurity requirements, motivated by the need to comply with European directives and legal requirements of the Czech authority. The methodology encompasses testing cybersecurity parameters of smart meters and related infrastructure, as well as evaluating wireless communication technologies in the context of cybersecurity requirements. The article contributes by summarizing the cybersecurity requirements, creating a testing methodology, and evaluating a real smart meter, using the proposed approach. The authors conclude by presenting a methodology that can be replicated and tools that can be used to test smart meters and the related infrastructure. This paper aims to propose a more effective solution and takes a significant step towards improving the cybersecurity of smart metering technologies.
PubMed: 37112383
DOI: 10.3390/s23084043 -
Sensors (Basel, Switzerland) Jul 2023Meter reading is an important part of intelligent inspection, and the current meter reading method based on target detection has problems of low accuracy and large...
Meter reading is an important part of intelligent inspection, and the current meter reading method based on target detection has problems of low accuracy and large error. In order to improve the accuracy of automatic meter reading, this paper proposes an automatic reading method for pointer-type meters based on the YOLOv5-Meter Reading (YOLOv5-MR) model. Firstly, in order to improve the detection performance of small targets in YOLOv5 framework, a multi-scale target detection layer is added to the YOLOv5 framework, and a set of Anchors is designed based on the lightning rod dial data set; secondly, the loss function and up-sampling method are improved to enhance the model training convergence speed and obtain the optimal up-sampling parameters; Finally, a new external circle fitting method of the dial is proposed, and the dial reading is calculated by the center angle algorithm. The experimental results on the self-built dataset show that the Mean Average Precision (mAP) of the YOLOv5-MR target detection model reaches 79%, which is 3% better than the YOLOv5 model, and outperforms other advanced pointer-type meter reading models.
PubMed: 37514937
DOI: 10.3390/s23146644 -
Journal of Sports Science & Medicine Jun 2018To validate the new PowerTap P1 pedals power meter (PP1), thirty-three cyclists performed 12 randomized and counterbalanced graded exercise tests (100-500 W), at 70, 85...
To validate the new PowerTap P1 pedals power meter (PP1), thirty-three cyclists performed 12 randomized and counterbalanced graded exercise tests (100-500 W), at 70, 85 and 100 rev·min cadences, in seated and standing positions. A scientific SRM system and a pair of PP1 pedals continuously recorded cadence and power output data. Significantly lower power output values were detected for the PP1 compared to the SRM for all workloads, cadences, and pedalling conditions (2-10 W, p < 0.05), except for the workloads ranged between 150 W to 350 W at 70 rev·min in seated position (p > 0.05). Strong Spearman's correlation coefficients were found between the power output values recorded by both power meters in a seated position, independently from the cadence condition (rho ≥ 0.987), although slightly lower concordance was found for the standing position (rho = 0.927). The mean error for power output values were 1.2%, 2.7%, 3.5% for 70, 85 and 100 rev·min, respectively. Bland-Altman analysis revealed that PP1 pedals underestimate the power output data obtained by the SRM device in a directly proportional manner to the cyclist's cadence (from -2.4 W to -7.3 W, rho = 0.999). High absolute reliability values were detected in the PP1 pedals (150-500 W; CV = 2.3%; SEM < 1.0 W). This new portable power meter is a valid and reliable device to measure power output in cyclists and triathletes for the assessment, training and competition using their own bicycle, although caution should be exercised in the interpretation of the results due to the slight power output underestimation of the PP1 pedals when compared to the SRM system and its dependence on both pedalling cadence and cyclist's position (standing vs. seated).
Topics: Adult; Bicycling; Cross-Sectional Studies; Exercise Test; Humans; Male; Muscle Strength; Reproducibility of Results; Sitting Position; Standing Position; Workload; Young Adult
PubMed: 29769832
DOI: No ID Found -
Sensors (Basel, Switzerland) Jan 2022A large number of power meters have become commercially available during the last decades to provide power output (PO) measurement. Some of these power meters were... (Review)
Review
A large number of power meters have become commercially available during the last decades to provide power output (PO) measurement. Some of these power meters were evaluated for validity in the literature. This study aimed to perform a review of the available literature on the validity of cycling power meters. PubMed, SPORTDiscus, and Google Scholar have been explored with PRISMA methodology. A total of 74 studies have been extracted for the reviewing process. Validity is a general quality of the measurement determined by the assessment of different metrological properties: Accuracy, sensitivity, repeatability, reproducibility, and robustness. Accuracy was most often studied from the metrological property (74 studies). Reproducibility was the second most studied (40 studies) property. Finally, repeatability, sensitivity, and robustness were considerably less studied with only 7, 5, and 5 studies, respectively. The SRM power meter is the most used as a gold standard in the studies. Moreover, the number of participants was very different among them, from 0 (when using a calibration rig) to 56 participants. The PO tested was up to 1700 W, whereas the pedalling cadence ranged between 40 and 180 rpm, including submaximal and maximal exercises. Other exercise conditions were tested, such as torque, position, temperature, and vibrations. This review provides some caveats and recommendations when testing the validity of a cycling power meter, including all of the metrological properties (accuracy, sensitivity, repeatability, reproducibility, and robustness) and some exercise conditions (PO range, sprint, pedalling cadence, torque, position, participant, temperature, vibration, and field test).
Topics: Bicycling; Exercise; Exercise Test; Humans; Reproducibility of Results; Torque
PubMed: 35009945
DOI: 10.3390/s22010386 -
Journal of Diabetes Science and... May 2017The accuracy of point-of-care blood glucose (BG) meters is important for the detection of dysglycemia, calculation of insulin doses, and the calibration of continuous... (Comparative Study)
Comparative Study
BACKGROUND
The accuracy of point-of-care blood glucose (BG) meters is important for the detection of dysglycemia, calculation of insulin doses, and the calibration of continuous glucose monitors. The objective of this study was to compare the accuracy of commercially available glucose meters in a challenging laboratory study using samples with a wide range of reference BG and hemoglobin values.
METHODS
Fresh, discarded blood samples from a hospital STAT laboratory were either used without modification, spiked with a glucose solution, or incubated at 37°C to produce 347 samples with an even distribution across reference BG levels from 20 to 440 mg/dl and hemoglobin values from 9 to 16 g/dl. We measured the BG of each sample with 17 different commercially available glucose meters and the reference method (YSI 2300) at the same time. We determined the mean absolute relative difference (MARD) for each glucose meter, overall and stratified by reference BG and by hemoglobin level.
RESULTS
The accuracy of different meters widely, exhibiting a range of MARDs from 5.6% to 20.8%. Accuracy was lower in the hypoglycemic range, but was not consistently lower in samples with anemic blood hemoglobin levels.
CONCLUSIONS
The accuracy of commercially available glucose meters varies widely. Although the sample mix in this study was much more challenging than those that would be collected under most use conditions, some meters were robust to these challenges and exhibited high accuracy in this setting. These data on relative accuracy and robustness to challenging samples may be useful in informing the choice of a glucose meter.
Topics: Blood Glucose; Blood Glucose Self-Monitoring; Data Accuracy; Humans; Reproducibility of Results
PubMed: 27697848
DOI: 10.1177/1932296816672237 -
Sensors (Basel, Switzerland) Jan 2020Optical sensors can be used to assess crop N status to assist with N fertilizer management. Differences between cultivars may affect optical sensor measurement. Cultivar...
Optical sensors can be used to assess crop N status to assist with N fertilizer management. Differences between cultivars may affect optical sensor measurement. Cultivar effects on measurements made with the SPAD-502 (Soil Plant Analysis Development) meter and the MC-100 (Chlorophyll Concentration Meter), and of several vegetation indices measured with the Crop Circle ACS470 canopy reflectance sensor, were assessed. A cucumber ( L.) crop was grown in a greenhouse, with three cultivars. Each cultivar received three N treatments, of increasing N concentration, being deficient (N1), sufficient (N2) and excessive (N3). There were significant differences between cultivars in the measurements made with both chlorophyll meters, particularly when N supply was sufficient and excessive (N2 and N3 treatments, respectively). There were no consistent differences between cultivars in vegetation indices. Optical sensor measurements were strongly linearly related to leaf N content in each of the three cultivars. The lack of a consistent effect of cultivar on the relationship with leaf N content suggests that a unique equation to estimate leaf N content from vegetation indices can be applied to all three cultivars. Results of chlorophyll meter measurements suggest that care should be taken when using sufficiency values, determined for a particular cultivar.
Topics: Chlorophyll; Crops, Agricultural; Cucumis sativus; Fertilizers; Nitrogen; Optical Imaging; Phenotype; Plant Leaves
PubMed: 31963226
DOI: 10.3390/s20020509 -
Scientific Reports Sep 2018This paper presents a power-free, self-contained microfluidic device in which a number of nanoliter-sized droplets can be parallelly and accurately metered and mixed for...
This paper presents a power-free, self-contained microfluidic device in which a number of nanoliter-sized droplets can be parallelly and accurately metered and mixed for high-throughput analysis and/or portable systems. In this system, the absorption of air by pre-degassed PDMS and the change of capillary force due to sudden narrowing of the channel cross-section provide the mechanism for actuating, metering and mixing the flow of fluid in the microfluidic channels and chambers. With an array of channels and capillary valves combined with an array of pre-degassed PDMS pump chambers, the device can perform multiple liquid dispensing and mixing in parallel, and its performance and reproducibility are also evaluated. As a practical application, the proposed device is used to screen crystallization conditions of lysozyme. This device needs neither external power nor complex instruments for fluid handling. Thus, it offers an easy-to-use, inexpensive and power-free way to perform multiple nanoliter-volume distinct reactions in parallel format and should be ideally suitable for individual laboratories for various applications such as enzyme assay, protein crystallization, drug discovery, and combinatorial chemistry.
Topics: Equipment Design; High-Throughput Screening Assays; Microfluidic Analytical Techniques; Microfluidics; Muramidase
PubMed: 30209328
DOI: 10.1038/s41598-018-31720-y -
Sensors (Basel, Switzerland) Jun 2023Accurate detection and timely treatment of component defects in substations is an important measure to ensure the safe operation of power systems. In this study, taking...
Accurate detection and timely treatment of component defects in substations is an important measure to ensure the safe operation of power systems. In this study, taking substation meters as an example, a dataset of common meter defects, such as a fuzzy or damaged dial on the meter and broken meter housing, is constructed from the images of manual inspection in power systems. There are several challenges involved in accurately detecting defects in substation meter images, such as the complex background, different meter sizes and large differences in the shapes of meter defects. Therefore, this paper proposes the PHAM-YOLO (Parallel Hybrid Attention Mechanism You Only Look Once) network for automatic detection of substation meter defects. In order to make the network pay attention to the key areas against the complex background of the meter defect images and the differences between different defect features, a Parallel Hybrid Attention Mechanism (PHAM) module is designed and added to the backbone of YOLOv5. PHAM integration of local and non-local correlation information can highlight these differences while remaining focused on the meter defect features. To improve the expressive ability of the feature map, a Spatial Pyramid Pooling Fast (SPPF) module is introduced, which pools the input feature map using a continuous fixed convolution kernel, fusing the feature maps of different receptive fields. Bounding box regression (BBR) is the key way to determine object positioning performance in defect detection. EIOU (Efficient Intersection over Union) is, therefore, introduced as a boundary loss function to solve the ambiguity of the CIOU (Complete Intersection Over Union) loss function, making the BBR regression more accurate. The experimental results show that the Average Precision Mean (mAP), Precision (P) and Recall (R) of the proposed PHAM-YOLO network in the dataset are 78.3%, 78.3%, and 79.9%, respectively, with mAP being improved by 2.7% compared to the original model and higher than SSD, Fast R-CNN, etc.
Topics: Algorithms; Records; Spine
PubMed: 37447900
DOI: 10.3390/s23136052 -
Journal of the American Heart... Dec 2021Background Knowledge gaps exist regarding the effect of time elapsed after stroke on the effectiveness of exercise training interventions, offering incomplete guidance...
Background Knowledge gaps exist regarding the effect of time elapsed after stroke on the effectiveness of exercise training interventions, offering incomplete guidance to clinicians. Methods and Results To determine the associations between time after stroke and 6-minute walk distance, 10-meter walk time, cardiorespiratory fitness and balance (Berg Balance Scale score [BBS]) in exercise training interventions, relevant studies in post-stroke populations were identified by systematic review. Time after stroke as continuous or dichotomized (≤3 months versus >3 months, and ≤6 months versus >6 months) variables and weighted mean differences in postintervention outcomes were examined in meta-regression analyses adjusted for study baseline mean values (pre-post comparisons) or baseline mean values and baseline control-intervention differences (controlled comparisons). Secondary models were adjusted additionally for mean age, sex, and aerobic exercise intensity, dose, and modality. We included 148 studies. Earlier exercise training initiation was associated with larger pre-post differences in mobility; studies initiated ≤3 months versus >3 months after stroke were associated with larger differences (weighted mean differences [95% confidence interval]) in 6-minute walk distance (36.3 meters; 95% CI, 14.2-58.5), comfortable 10-meter walk time (0.13 m/s; 95% CI, 0.06-0.19) and fast 10-meter walk time (0.16 m/s; 95% CI, 0.03-0.3), in fully adjusted models. Initiation ≤3 months versus >3 months was not associated with cardiorespiratory fitness but was associated with a higher but not clinically important Berg Balance Scale score difference (2.9 points; 95% CI, 0.41-5.5). In exercise training versus control studies, initiation ≤3 months was associated with a greater difference in only postintervention 6-minute walk distance (baseline-adjusted 27.3 meters; 95% CI, 6.1-48.5; fully adjusted, 24.9 meters; 95% CI, 0.82-49.1; a similar association was seen for ≤6 months versus >6 months after stroke (fully adjusted, 26.6 meters; 95% CI, 2.6-50.6). Conclusions There may be a clinically meaningful benefit to mobility outcomes when exercise is initiated within 3 months and up to 6 months after stroke.
Topics: Exercise Therapy; Humans; Regression Analysis; Stroke; Time-to-Treatment; Treatment Outcome
PubMed: 34913357
DOI: 10.1161/JAHA.121.022588