Distributed Measurement System Research Articles

A Performance Analysis of Security Protocols for Distributed Measurement Systems Based on Internet of Things with Constrained Hardware and Open Source Infrastructures.

The widespread adoption of Internet of Things (IoT) devices in home, industrial, and business environments has made available the deployment of innovative distributed measurement systems (DMS). This paper takes into account constrained hardware and a security-oriented virtual local area network (VLAN) approach that utilizes local message queuing telemetry transport (MQTT) brokers, transport layer security (TLS) tunnels for local sensor data, and secure socket layer (SSL) tunnels to transmit TLS-encrypted data to a cloud-based central broker. On the other hand, the recent literature has shown a correlated exponential increase in cyber attacks, mainly devoted to destroying critical infrastructure and creating hazards or retrieving sensitive data about individuals, industrial or business companies, and many other entities. Much progress has been made to develop security protocols and guarantee quality of service (QoS), but they are prone to reducing the network throughput. From a measurement science perspective, lower throughput can lead to a reduced frequency with which the phenomena can be observed, generating, again, misevaluation. This paper does not give a new approach to protect measurement data but tests the network performance of the typically used ones that can run on constrained hardware. This is a more general scenario typical for IoT-based DMS. The proposal takes into account a security-oriented VLAN approach for hardware-constrained solutions. Since it is a worst-case scenario, this permits the generalization of the achieved results. In particular, in the paper, all OpenSSL cipher suites are considered for compatibility with the Mosquitto server. The most used key metrics are evaluated for each cipher suite and QoS level, such as the total ratio, total runtime, average runtime, message time, average bandwidth, and total bandwidth. Numerical and experimental results confirm the proposal's effectiveness in foreseeing the minimum network throughput concerning the selected QoS and security. Operating systems yield diverse performance metric values based on various configurations. The primary objective is identifying algorithms to ensure suitable data transmission and encryption ratios. Another aim is to explore algorithms that ensure wider compatibility with existing infrastructures supporting MQTT technology, facilitating secure connections for geographically dispersed DMS IoT networks, particularly in challenging environments like suburban or rural areas. Additionally, leveraging open firmware on constrained devices compatible with various MQTT protocols enables the customization of the software components, a crucial necessity for DMS.

A laboratory investigation into tyre-pavement contact behaviour of passenger car

ABSTRACT Understanding tyre-pavement contact behaviour helps to address pavement skid resistance which is highly related to traffic safety. In this study, a pressure distribution measurement system was employed to investigate the tyre-pavement contact behaviour of a passenger car in laboratory. The pavement macrotexture was characterised by a 3D scanner and the sand patch method. It was shown that the asphalt pavement gradation, the vertical force, the tyre inclination angle and the tyre pressure significantly have effects on tyre-pavement contact behaviour. The cumulative frequency curve of tyre-pavement contact stress can be well fitted by the Boltzmann model. Under the vertical force of 4 kN, the average contact stress increases significantly when the inclination angle exceeds 3.2°, while an inclination angle within 3.2° has almost no effect. The force on the rib on the side that the tyre leans to changes the most with the inclination angle. As the tyre pressure increases, the average contact stress increases linearly and the contact area decreases linearly. With the increase of tyre pressure, the contact region gradually shrinks towards the middle and the contact force slightly increases in the middle and decreases at the edges.

Distributed measurement system calibration method with automatic networking mechanism

This paper presents a new method that balances accuracy and efficiency in the process of coordinate unification for distributed measurement systems. The method unifies the local coordinate systems of any two measuring units by installing a measuring point on the unit as a marker point and measuring the marker points between them in the working area, combined with the distance between the marker points. Moreover, it enables automatic networking of newly added or moved measurement units with the original measurement network, thereby further improving the efficiency of the dynamic measurements made using the system. The key factors affecting the accuracy of calibration achieved using this method were analysed via simulations. The results indicate that the accuracy of length measurement using the proposed methods is within 0.1 mm m−1 when the measurement units are distributed among the four corners of a rectangle with an area of 50 m2 or more. The experiments indicate that four measurement units calibrated using this method over an area of 35 m2 achieve an accuracy of within 0.2 mm m−1 and 0.1 mm standard deviations for length and three-dimensional coordinate measurements, respectively. Compared with traditional coordinate-unification methods, the proposed method simplifies the calibration process, improves the calibration efficiency by more than ten times, and significantly reduces the calibration time. It is universally applicable in the calibration of large-space distributed measurement systems.

Study on Contact Stress Distribution Characteristics and Damage of Plug Seedlings Based on Flexible Pressure Sensor.

At present, there is a problem that the growth quality is reduced due to damage to the plug seedling pot during the transplanting process. In this study, the pressure distribution measurement system was used to measure the contact area of plug seedlings when they collided with the ground. The effects of seedling age and forward speed on the characteristics of contact stress distribution and potting damage were investigated through a single-factor experiment. The results were comprehensively considered based on the single-factor test, and the Box-Behnken test was used to optimize the design. The matrix loss rate was used as the evaluation index to determine the optimal parameter combination for transplanting: the tray specification was 72, the seedling age was 30 d, and the forward speed was 1.25 km·h-1. This study can provide a reference and technical support for further research on pot damage in plug seedling transplanting. The optimized parameters can provide practical guidance for reducing pot damage and improving growth quality during transplanting plug seedlings.

A fast calibration method for distributed measurement systems

Aiming at the distributed measurement system multi-equipment coordinated measurement, the data measured by each transmitting station are unified under a common coordinate system, which has the problems of complicated operation and high time and cost. In this paper, a fast calibration method for distributed measurement systems based on standard devices is proposed. The method designs a new type of architectural calibration board with non-coplanar measurement nodes, calculates the coordinates of the measurement nodes using geometric relations, solves the initial values of the system parameters, and substitutes the initial values into the L-M least squares algorithm for iterative optimization so that it only needs to carry out one scanning measurement for each reference position in the calibration process to complete the calibration. We designed an experiment in which a distributed measurement system consisting of four transmitting stations measured three standard rods (1650.073, 1156.704, and 875.950 mm) sequentially after calibration in a measuring space of 5 × 5 × 3 m3. The experimental results show that under the premise of ensuring that the measurement accuracy is better than 0.20 mm, the calibration of the parameters of the distributed measurement system can be completed within 20 min.

Analysis of tyre-pavement contact behaviour of heavy truck in full-scale test

ABSTRACT Tyre-pavement contact behaviour is one of the core issues in pavement engineering. In this study, the tyre-pavement contact behaviour was investigated in full-scale tests. The pavement texture was characterised by a 3D scanner and the sand patch method. The data of tyre-pavement contact stress were collected by a pressure distribution measurement system. The characteristics of the tyre-pavement contact stress distribution were explored by introducing the Boltzmann model. The feasibility of the Hertz model in assessing the tyre-pavement contact behaviour was evaluated. The results showed that the tyre-pavement carries a larger load by extending the contact area in longitudinal direction and increasing the contact stress mainly at the lateral edges. The pavement texture has significant effects on the contact behavior. Under the regular tyre vertical force range, the value of contact stress is within 1000 kPa for about 80% of the tyre-pavement contact area, but the maximum contact stress can be up to 3000 kPa. The Boltzmann model can be used to fit the contact stress distribution, and some parameters of the model have linear relationships with pavement surface macrotexture. The Hertz model can reflect the average state of tyre-pavement contact behaviour.

Development of a Temperature Distribution Measurement System for Transmission Oil for Transportation Equipment

In this study, an optical sensor using thermo-sensitive phosphor and its measurement system for visualizing and measuring the temperature distribution in an arbitrary cross-section of transmission oil using one type of phosphor, whose peak wavelength changes with temperature, is proposed. Because the intensity of the excitation light is gradually attenuated by the scattering of the laser light owing to microscopic impurities in the oil, we attempted to reduce the scattering effect by increasing the excitation light wavelength. Therefore, Pyrromethene 597 was selected as the optical sensor using thermo-sensitive phosphor, and a DPSS (Diode Pumped Solid State) laser with a wavelength of 532 nm was used as the excitation light. Using this measurement system, we measured the temperature distribution of a vertical buoyant jet of transmission oil and validated the measurement method. In addition, it was shown that this measurement system could be applied to the measurement of the temperature distribution in transmission oil with cavitation foaming.

Measurement and Applications: The Role of Communication Technologies in Developing Distributed Measurement Systems and Measurement Applications

Communication technologies are of primary importance for today's activity, since they contribute to achieving a lot of services for humans, from simple phone calls to advanced multimedia services, banking activities, and healthcare, to cite a few [1]. They are also the key factor of many measurement applications in the contexts of industry 4.0, transportation, environmental monitoring, telemetering, building automation, and the emerging applications of the Internet of Things (IoT) and Industrial Internet of Things (IIoT) [2]–[4]. In other words, communication technologies enable the concept of “Networking for measurements” which explains the crucial role of networks for measurement applications.

Pressure Evaluation of Seamless Yoga Leggings Designed with Partition Structure

Abstract It is a novel approach to design the partition structure of clothing according to the deformation of the human body surface skin during exercise. The functional evaluation of these products remains unknown, and there is limited knowledge about the effects of the partition structure design on the pressure comfort of clothing. This research carried out a partitioned structural design of the leggings based on the skin deformation of the lower limbs of the human body during yoga exercise and developed two styles of seamless yoga leggings. The skin pressure exerted by the new seamless yoga leggings was compared with two commercial yoga leggings. Eight female college students were invited to wear all the yoga leggings samples and perform yoga exercises. The skin pressure exerted by yoga leggings was measured by the German novel-Pliance multipurpose pressure distribution measurement system on 10 body positions. The results showed that yoga leggings designed with a partitioned structure exert a comfortable pressure on the skin during yoga exercise, and the pressure change was smaller under different yoga postures, which has better pressure stability. The partition structure design model of seamless yoga leggings was optimized, which provided a reference for the functional partition design and product development of seamless yoga leggings.

Vibration Distribution Measurement of Car Door and Engine Head Using OPPA Vibration Distribution Analyzer

In order to address the issue of vibration, it is crucial to accurately measure the vibration distribution. The authors previously developed the one-pitch phase analysis (OPPA) method, which allows for rapidly capturing the three-dimensional shape of a flat object. By integrating this method into a system, an OPPA vibration distribution measurement system was created, utilizing a line light source consisting of LEDs or optical fibers and also a high-speed camera to measure the vibrations of three-dimensional objects without physical contact. To further extend the application of the OPPA method to larger objects, such as cars, in this paper, a new system is introduced using a commercially available projector using a liquid crystal display (LCD) instead of a liner light source and a glass grating. This new system, which employs an ultra-short throw projector, is highly sensitive in displacement measurements and provides a wide-area analysis. These kinds of projectors produce noises at the frequency of the cooling fan and the refresh rate of the LCD. However, in this study, these noise sources were also examined. The capabilities of the new system are demonstrated through its application to the measurement of vibrations in a car door and an engine head. The measurement system and examples of its application are presented.

Nonlinear Modeling of Contact Stress Distribution in Thin Plate Substrates Subjected to Aspect Ratio.

The foundation substrate's basal contact stresses are typically thought to have a linear distribution, although the actual form is nonlinear. Basal contact stress in thin plates is experimentally measured using a thin film pressure distribution system. This study examines the nonlinear distribution law of basal contact stresses in thin plates with various aspect ratios under concentrated loading, and it establishes a model for the distribution of contact stresses in thin plates using an exponential function that accounts for aspect ratio coefficients. The outcomes demonstrate that the thin plate's aspect ratio significantly affects how the substrate contact stress is distributed during concentrated loading. The contact stresses in the thin plate's base exhibit significant nonlinearity when the aspect ratio of the test thin plate is greater than 6~8. The aspect ratio coefficient-added exponential function model can better optimize the strength and stiffness calculations of the base substrate and more accurately describe the actual distribution of contact stresses in the base of the thin plate compared to linear and parabolic functions. The correctness of the exponential function model is confirmed by the film pressure distribution measurement system that directly measures the contact stress at the base of the thin plate, providing a more accurate nonlinear load input for the calculation of the internal force of the base thin plate.

Research on Distributed Measurement and Control System Based on FlexRay Bus

With the purpose of the design problem of electromagnetic launch distributed measurement and control system, this paper proposes a design method of scalable large-scale distributed interconnected measurement and control system based on FlexRay bus. The task execution time deviation of each node in the distributed system, including phase deviation and frequency deviation, is reduced by using the macro tick generation process and clock synchronization process to achieve task synchronization in the distributed system. The synchronization of timing generation is realized based on the universal clock technology. When the timing interval is zero, the pulse power units are guaranteed to be close to the ideal full synchronization, thus ensuring that the released energy during transmission is close to the design value. In the state of adjustable timing, when the pulse power supply module conducts pulse discharge, the trigger discharge times of the modules are set according to the load needs. The flat top, sawtooth, and other characteristic current waveforms are adjusted accurately. At the same time, a combined multi-level protection structure based on hardware and software is realized. The verification results show that the distributed electromagnetic launch measurement and control system implemented in this paper can meet the high efficiency, fast and continuous launch target.

Distributed Optical Measurement System for Plate Fin Heat Exchanger

The acquirement of the flow information in plate-fin heat exchanger (PFHE) is limited by its metal structure and complex flow condition. This work develops a new distributed optical measurement system to obtain flow information and boiling intensity. The system utilizes numerous optical fibers installed at the surface of the PFHE to detect optical signals. The attenuation and fluctuation of the signals reflect the variation of the gas-liquid interfaces and can be further used to estimate the boiling intensity. Practical experiments of flow boiling in PFHE with different heating fluxes have been carried out. The results verify that the measurement system can obtain the flow condition. Meanwhile, according to the results, the boiling development in PFHE can be divided into four stages with the increase in the heating flux, including the unboiling stage, initiation stage, boiling developing stage, and fully developed stage.

Influence of obstructions on obstacle-crossing motion during walking.

[Purpose] The purpose of this study was to clarify whether the presence of obstructions changes the crossing motion during walking based on the visual perception of obstacles. [Participants and Methods] We included 25 healthy university students as the participants in this study. They were asked to step over obstacles while walking under two conditions i.e., with obstruction and without obstruction. We analyzed the distance between the foot and obstacle (clearance), trajectory of foot pressure movement and distribution as measured by a foot pressure distribution measurement system, and stance phase time. [Results] No significant differences were found between the two conditions for either clearance or foot pressure distribution. In other words, no difference in crossing motion was observed after visual recognition of the obstacle, both in the presence or absence of the obstruction. [Conclusion] The results suggest that no differences exist in the accuracy of recognizing visual information about an obstacle through different mechanisms of selective visual attention.

Comparison of Algorithms for the AI-Based Fault Diagnostic of Cable Joints in MV Networks

Electrical utilities and system operators (SOs) are constantly looking for solutions to problems in the management and control of the power network. For this purpose, SOs are exploring new research fields, which might bring contributions to the power system environment. A clear example is the field of computer science, within which artificial intelligence (AI) has been developed and is being applied to many fields. In power systems, AI could support the fault prediction of cable joints. Despite the availability of many legacy methods described in the literature, fault prediction is still critical, and it needs new solutions. For this purpose, in this paper, the authors made a further step in the evaluation of machine learning methods (ML) for cable joint health assessment. Six ML algorithms have been compared and assessed on a consolidated test scenario. It simulates a distributed measurement system which collects measurements from medium-voltage (MV) cable joints. Typical metrics have been applied to compare the performance of the algorithms. The analysis is then completed considering the actual in-field conditions and the SOs’ requirements. The results demonstrate: (i) the pros and cons of each algorithm; (ii) the best-performing algorithm; (iii) the possible benefits from the implementation of ML algorithms.

油葵穴盘苗钵体离散元参数标定与试验验证

The movement of plug seedlings and the pots damage mechanism are deeply studied during the planting process, and the planting components are optimized. The Tekscan pressure distribution measurement system was used to measure the mechanical characteristics of the drop impact between the whole plug seedlings and the pots. The relative error between the collision impact force of the plug seedlings and the collision impact force of the pot is less than 20%. Therefore, a drop impact test using the pot allows the whole plug seedling to be characterized. The Hertz-Mindlin with bonding model was used to build a simulation model of the pot based on essential physical parameters. The Plackett-Burman test and the steepest climbing test determined the significant parameters and optimal intervals affecting the collision impact force: the rolling friction coefficient between the pot and pot was 0.35~0.38, the bond stiffness was 0.2~0.6 MN·m-3, and the bond radius was 1.56~1.98 mm. Finally, the Box-Behnken test was performed and the quadratic regression model of the collision impact force was developed. Taking the collision impact force with a drop height of 350 mm as the target, the optimal solution is obtained: the rolling friction coefficient between the pot and pot was 0.35, the bond stiffness was 0.53 MN·m-3, and bond radius 1.97 mm. The average value was used for other insignificant influence parameters. The simulation results are compared with the physical test, and the relative error is 3.65%. Therefore, the pot model established by this simulation parameter can represent the actual drop impact of the pots.

Lower leg blood pressure decreases while calf external pressure increases with the angulation of the Trendelenburg position in the lithotomy position with calf- and foot-supported leg holders.

Patients who underwent lower abdominopelvic surgeries in the lithotomy position (LP) and the Trendelenburg position (TP) with the leg holder are at risk of developing well leg compartment syndrome (WLCS). However, contributing factors related to the LP with TP associated with WLCS are unknown. This study aimed to investigate the associations between external pressure at the calf in the LPs at different angulations of the TP and physiological characteristics. Eighty-four university students (age, 21.7 ± 0.9; 42 men and 42 women) voluntarily participated in the study. The awake participants were placed in the LPs using the calf- and foot-supported leg holder at 0° (horizontal level), 5°, 10°, and 20° head-down tilts by moving the electric operating table. The peak contact pressure (pCP) was measured at the calf as a representative external pressure using the pressure distribution measurement system BIG-MAT®. Lower leg blood pressure significantly decreased with TP angulation, while calf pCP significantly increased with it at 0°, 5°, 10°, and 20° head-down tilts (39.4 ± 15.2, 46.5 ± 17.7, 47.2 ± 16.9, and 50.3 ± 17.6mmHg, respectively). The calf pCP with a 10° head-down tilt was correlated positively with the calf total force (P < 0.001) and negatively with the calf contact area (P < 0.001). Blood hypoperfusion due to low lower leg blood pressure secondary to lower leg elevation and head-down tilt, and high calf external pressure due to direct external compression from the leg holder where it is loaded may contribute to WLCS.

Study on the Impact Damage Characteristics of Transplanting Seedlings Based on Pressure Distribution Measurement System

Collision is one of the main causes of mechanical damage to the seedling during transplanting. To reveal the impact damage characteristics of plug seedlings, the kinetics equations of seedling collision were established based on Hertz’s contact theory, and the kinematic characteristics, elastoplastic deformation, and collision damage during seedling collision were analyzed using high-speed photography. Using the Tekscan pressure distribution measurement system, the significant levels of various factors that affect impact peak force (IPF) and damage of seedling pot (DSP) were studied, the change rule of contact pressure distribution of seedlings under significant factors was measured, and a regression model between IPF and DSP was established. The results showed that collision material, drop height and seedling pot size had significant effects on IPF and DSP. The contact pressure area of different collision materials from large to small was soil block, steel, and ABS plastic. The contact pressure area of seedlings of different pot sizes was big, medium, and small in descending order. At a dropping height of 50~350 mm, a contact pressure &gt; 10 kPa accounted for the major contact pressure area, which is the main reason for collision damage of the seedling pot. Linear regression models between IPF and DSP under different factors were established, and the determination coefficients (R2) were 0.98 and 0.94, respectively. The results provided a theoretical basis for understanding the collision damage mechanism of the plug seedling and how to reduce damage during transplanting.

Embedded Sensors for Structural Health Monitoring: Methodologies and Applications Review.

Sensing Technology (ST) plays a key role in Structural Health-Monitoring (SHM) systems. ST focuses on developing sensors, sensory systems, or smart materials that monitor a wide variety of materials' properties aiming to create smart structures and smart materials, using Embedded Sensors (ESs), and enabling continuous and permanent measurements of their structural integrity. The integration of ESs is limited to the processing technology used to embed the sensor due to its high-temperature sensitivity and the possibility of damage during its insertion into the structure. In addition, the technological process selection is dependent on the base material's composition, which comprises either metallic or composite parts. The selection of smart sensors or the technology underlying them is fundamental to the monitoring mode. This paper presents a critical review of the fundaments and applications of sensing technologies for SHM systems employing ESs, focusing on their actual developments and innovation, as well as analysing the challenges that these technologies present, in order to build a path that allows for a connected world through distributed measurement systems.

Experimental Study on Pot Damage and Contact Stress Distribution Characteristics of Oil Sunflower Plug Seedlings

To reveal the collision damage mechanisms of plug seedlings and improve the quality of seedlings, the kinetics equations of the plug seedlings were established based on the generalized Hertz-theory. The influence laws of different factors on pot damage were obtained through a drop impact test. The Tekscan pressure distribution measurement system measured the collision impact force, and the orthogonal tests were conducted. The test showed that the influence of the collision impact force was on the order of plug specification &gt; drop height &gt; contact material. The Tekscan pressure distribution measurement system measured the change law of contact stress distribution under significant influencing factors. The test results showed that the collision contact area between the plug seedlings and contact materials from large to small was soil, steel, and ABS plastic. The collision contact area between the plug seedlings and other plug specifications was 50 plug, 72 plug, and 105 plug from the largest to the smallest. When the plug seedlings collided with contact materials, the average contact stress between the seedlings and the steel plate ranged from 19.4 kPa to 22.8 kPa. When the plug seedlings of various sizes collided with steel plates, the average contact stress was ordered as 105 plug, 72 plug and 50 plug in descending order. A linear regression model between collision impact force and matrix loss rate under different factors was established based on the pressure data collected by the Tekscan pressure distribution measurement system. This study provides a basis for exploring the impact damage mechanisms of plug seedlings and improving the seedling quality.