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Narumi, Keisuke, Toshio Fukuda i Fumihito Arai. "Design and Characterization of Load Sensor with AT-Cut QCR for Miniaturization and Resolution Improvement". Journal of Robotics and Mechatronics 22, nr 3 (20.06.2010): 286–92. http://dx.doi.org/10.20965/jrm.2010.p0286.
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The compact load sensor we developed uses an AT-cut quartz crystal resonator whose resonance frequency changes under external load, featuring high sensitivity, high-speed response, and a wide measurement range – plus superior temperature and frequency stability. The vulnerability of previous quartz crystal resonators to stress concentration in bending prevented them from being more widely applied to load measurement. The sensor we developed maintains the quartz crystal resonator safely. Our objective here is to improve load measurement resolution and to miniaturize the sensor, which we did designing novel retention of the quartz crystal resonator fixed vertical to applied load. The new load sensor’s resolution is 3.21 mN –seven times better than conventional load sensors.
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Guo, Jingjing, Tiesuo Geng, Huaizhi Yan, Lize Du, Zhe Zhang i Changsen Sun. "Implementation of a Load Sensitizing Bridge Spherical Bearing Based on Low-Coherent Fiber-Optic Sensors Combined with Neural Network Algorithms". Sensors 21, nr 1 (23.12.2020): 37. http://dx.doi.org/10.3390/s21010037.
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Low-coherent fiber-optic sensors combined with neural network algorithms were designed to carry out a load-sensitizing spherical bearing. Four sensing fibers were wound around the outside of the pot support of the spherical bearing uniformly deployed from upper to bottom. The upper three were configured in a distributed way to respond to the applied load as a function of the three strain sensors. The bottom one was employed as a temperature compensation sensor. A loading experiment was implemented to test the performance of the designed system. The results showed that there was a hysteresis in all the three sensors between loading and unloading process. The neural network algorithm is proposed to set up a function of the three sensors, treated as a set of input vectors to establish the input-output relationship between the applied loads and the constructed input vectors, in order to overcome the hysteresis existing in each sensor. An accuracy of 6% for load sensing was approached after temperature compensation.
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Gattringer, Hubert, Andreas Müller i Philip Hoermandinger. "Design and Calibration of Robot Base Force/Torque Sensors and Their Application to Non-Collocated Admittance Control for Automated Tool Changing". Sensors 21, nr 9 (21.04.2021): 2895. http://dx.doi.org/10.3390/s21092895.
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Robotic manipulators physically interacting with their environment must be able to measure contact forces/torques. The standard approach to this end is attaching force/torque sensors directly at the end-effector (EE). This provides accurate measurements, but at a significant cost. Indirect measurement of the EE-loads by means of torque sensors at the actuated joint of a robot is an alternative, in particular for series-elastic actuators, but requires dedicated robot designs and significantly increases costs. In this paper, two alternative sensor concept for indirect measurement of EE-loads are presented. Both sensors are located at the robot base. The first sensor design involves three load cells on which the robot is mounted. The second concept consists of a steel plate with four spokes, at which it is suspended. At each spoke, strain gauges are attached to measure the local deformation, which is related to the load at the sensor plate (resembling the main principle of a force/torque sensor). Inferring the EE-load from the so determined base wrench necessitates a dynamic model of the robot, which accounts for the static as well as dynamic loads. A prototype implementation of both concepts is reported. Special attention is given to the model-based calibration, which is crucial for these indirect measurement concepts. Experimental results are shown when the novel sensors are employed for a tool changing task, which to some extend resembles the well-known peg-in-the-hole problem.
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Hujer, Jan, Menghuot Phan, Tomáš Kořínek, Petra Dančová i Miloš Müller. "Photolithographically Home-Made PVDF Sensor for Cavitation Impact Load Measurement". MATEC Web of Conferences 328 (2020): 01004. http://dx.doi.org/10.1051/matecconf/202032801004.
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Piezoelectric PVDF sensors offer a unique option for the measurement of cavitation aggressiveness represented by the magnitude of impacts due to cavitation bubble collapses near walls. The aggressiveness measurement requires specific sensors shape and area, whereas commercial PVDF sensors are fabricated in limited geometry and size ranges. The photolithography method offers a possibility of production of home-made PVDF sensors of arbitrary shape and size. This paper deals with the calibration of a photolithographically home-made PVDF sensor for the cavitation impact load measurement. The calibration of sensors was carried out by the ball drop method. Sensors of different sizes were fabricated by the photolithography method from multi-purpose both side metallized PVDF sheet. The standard technology used for the fabrication of printed circuit boards was utilized. Commercial PVDF sensors of the same size were calibrated and the calibration results were compared with the home-made sensors. The effect of size and the effect of one added protective layer of Kapton tape on a sensor sensitivity were investigated.
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Lee, Woojin, Won-Je Lee, Sang-Bae Lee i Rodrigo Salgado. "Measurement of pile load transfer using the Fiber Bragg Grating sensor system". Canadian Geotechnical Journal 41, nr 6 (1.12.2004): 1222–32. http://dx.doi.org/10.1139/t04-059.
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A series of laboratory and field tests were performed to evaluate the applicability of an optical fiber sensor system in the instrumentation of piles. A multiplexed sensor system, constructed by arranging several Fiber Bragg Grating (FBG) sensors along a single line of optical fiber, is capable of measuring local axial strains as a function of wavelength shifts. The distributions of axial load in three model piles and a field test pile evaluated from the strains measured by FBG sensors are found to be comparable, in terms of both magnitude and trend, with those obtained from conventional strain gauges. This suggests that the FBG sensor system is an effective tool for the analysis of the axial load transfer in piles. The successful instrumentation of a soilcement injected precast (SIP) pile using FBG sensors suggests that the use of these sensors in drilled shafts and other types of cast in situ concrete piles is feasible. With the rapid advance of optical fiber sensor technology, the economics of the use of optical fiber sensors in this type of instrumentation is expected to improve significantly in coming years.Key words: pile foundation, load transfer, fiber optic sensor, Fiber Bragg Grating sensor.
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Samuelsson, Oscar, Gustaf Olsson, Erik Lindblom, Anders Björk i Bengt Carlsson. "Sensor bias impact on efficient aeration control during diurnal load variations". Water Science and Technology 83, nr 6 (25.01.2021): 1335–46. http://dx.doi.org/10.2166/wst.2021.031.
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Abstract This study highlights the need to increase our understanding of the interplay between sensor drift and the performance of the automatic control system. The impact from biased sensors on the automatic control systems is rarely considered when different control strategies are assessed in water resource recovery facilities. Still, the harsh measurement environment with negative effects on sensor data quality is widely acknowledged. Simulations were used to show how sensor bias in an ammonium cascade feedback controller impacts aeration energy efficiency and total nitrogen removal in an activated sludge process. Response surface methodology was used to reduce the required number of simulations, and to consider the combined effect of two simultaneously biased sensors. The effects from flow variations, and negatively biased ammonium (−1 mg/L) and suspended solids sensors (−500 mg/L) reduced the nitrification aeration energy efficiency by between 7 and 25%. Less impact was seen on total nitrogen removal. There were no added non-linear effects from the two simultaneously biased sensors, apart from an interaction between a biased ammonium sensor and dissolved oxygen sensor located in the last aerated zone. Negative effects from sensor bias can partly be limited if the expected bias direction is considered when the controller setpoint-limits are defined.
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Darade, Santosh Ashokrao, i M. Akkalakshmi. "Extensive Literature Survey on Load Balancing in Software-Defined Networking". International Journal of Business Data Communications and Networking 16, nr 2 (lipiec 2020): 1–19. http://dx.doi.org/10.4018/ijbdcn.2020070101.
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The localization of underwater sensors is the most crucial task in underwater wireless sensor networks (UWSNs). The sensors, which are situated under the water, sense data from the environment, and sensed data is transmitted to the monitoring station. Although the monitoring station receives the sensed data, the data is meaningless without knowing the exact position of the sensor. Localization is the major issue in UWSN to be resolved. There are several localization algorithms available for terrestrial wireless sensor networks (WSN), but there are comparatively few localization algorithms available for UWSNs. An improved range-based localization method is introduced in this paper to discover localization issue. To evaluate the location of the target sensors, localization error is further to be reduced. The localization error is reduced by applying the whale optimization algorithm (WOA) in this technique. Simulation results demonstrate that performance metrics of the proposed approach outperform the existing work in terms of localization error and localization coverage.
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Zhao, Yi Ding, i Xiao Li Liu. "The Study of Vehicle Load Monitoring System". Applied Mechanics and Materials 505-506 (styczeń 2014): 384–87. http://dx.doi.org/10.4028/www.scientific.net/amm.505-506.384.
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Overloading the impact on traffic safety, measuring the deformation of leaf spring form the start, a vehicle load measuring system was designed based on ultrasonic sensors. In this article, the mathematics model of steel plate deformation and load is discussed upon the mechanics principle and obtain the relationship of load and deformation. Processing the data that the ultrasonic sensors measured by single-chip and using temperature sensor to compensate, it comes to the result of vehicle load.According to the test, the system achieved the purpose of real time measurement of vehicle load, and it is useful.
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Brunetti, Luciano, Luca Oberto i Emil T. Vremera. "Thermoelectric Sensors as Microcalorimeter Load". IEEE Transactions on Instrumentation and Measurement 56, nr 6 (grudzień 2007): 2220–24. http://dx.doi.org/10.1109/tim.2007.908135.
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Park, Dong Jin, Min Kyu Kang, Jong Hyun Lee, Seok Soon Lee i Hyo Seok Jung. "LOAD CELL DESIGN USING FIBER BRAGG GRATING SENSORS". International Journal of Modern Physics: Conference Series 06 (styczeń 2012): 203–8. http://dx.doi.org/10.1142/s2010194512003182.
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A load cell is the representative converter that changes load to the quantity of electricity. The load cell is used to a large mechanical structure and offshore structures to measure the force. Currently, the load cell using electrical strain gauges are commonly used. Basic measuring principle of electrical strain gauge is the electrical method. A load cell with electrical strain gauges is not available in the electromagnetic and corrosion environment. A Fiber Bragg Grating (FBG) sensor is not affected by the EMI (Electro Magnetic Interference)/EMC (Electro Magnetic Compatibility) and is strong in corrosion under the sea water. In this paper, we use the FBG sensors to make a load cell under the sea water condition and the electromagnetic environment and show FBG sensors' availability.
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Ehrlich, Jacques, Georges Coche i Amal Zerrouki. "Smart sensor research at the French Laboratoire Central des Ponts et Chaussées". Sensor Review 17, nr 3 (1.09.1997): 240–47. http://dx.doi.org/10.1108/02602289710172373.
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Highlights two works being carried out by the French Laboratoire Central des Ponts et Chaussées in the field of smart sensors. The first concerns the knowledge of loads applied to bridges in order to evaluate extreme load effects and fatigue load effects over their lifetime. To achieve these goals, a data acquisition system based on smart sensors extracting and classifying extrema in the traffic loads signal has been developed. The second concerns distributed systems software cost reduction by means of a generic model. The aim of the model is the design of a software generator for smart sensor‐based systems. The key of the system is in the description of an instrumentation plan under the form of a data dependence graph (DDG). The goal of the generator is to map and “execute” that DDG on the physical architecture according to the number of transducers, their affectation to the smart sensors and a PC‐based system controller.
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J. Majid, Amir. "Scenarios of Lifetime Extension Algorithms for Wireless Ad Hoc Networks". International journal of Computer Networks & Communications 12, nr 6 (30.11.2020): 83–97. http://dx.doi.org/10.5121/ijcnc.2020.12606.
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An Algorithm to extend sensor lifetime and energy is implemented for different scenarios of ad hoc and wireless sensor networks. The goal is to prolong the lifetimes of sensors, covering a number of targeted zones by creating subsets of sensors, in which each subset covers entirely the targeted zones. Probabilistic analysis is assumed in which each sensor covers one or more targets, according to their coverage failure probabilities. Case studies of different sensor subsets arrangements are considered such as load switching, variable target load demands as well as a perturbation in sensor planner locations.
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Zhou, Wu, Dong Wang, Huijun Yu i Bei Peng. "A pressure-deformation analytical model for rectangular diaphragm of MEMS pressure sensors". Modern Physics Letters B 31, nr 05 (20.02.2017): 1750046. http://dx.doi.org/10.1142/s0217984917500464.
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Rectangular diaphragm is commonly used as a pressure sensitive component in MEMS pressure sensors. Its deformation under applied pressure directly determines the performance of micro-devices, accurately acquiring the pressure–deflection relationship, therefore, plays a significant role in pressure sensor design. This paper analyzes the deflection of an isotropic rectangular diaphragm under combined effects of loads. The model is regarded as a clamped plate with full surface uniform load and partially uniform load applied on its opposite sides. The full surface uniform load stands for the external measured pressure. The partial load is used to approximate the opposite reaction of the silicon island which is planted on the diaphragm to amplify the deformation displacement, thus to improve the sensitivity of the pressure sensor. Superposition method is proposed to calculate the diaphragm deflections. This method considers separately the actions of loads applied on the simple supported plate and moments distributed on edges. Considering the boundary condition of all edges clamped, the moments are constructed to eliminate the boundary rotations caused by lateral load. The diaphragm’s deflection is computed by superposing deflections which produced by loads applied on the simple supported plate and moments distributed on edges. This method provides higher calculation accuracy than Galerkin variational method, and it is used to analyze the influence factors of the diaphragm’s deflection, includes aspect ratio, thickness and the applied force area of the diaphragm.
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Gupta, Deepak K., i Anoop K. Dhingra. "Load Reconstruction Technique UsingD-Optimal Design and Markov Parameters". Shock and Vibration 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/605695.
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This paper develops a technique for identifying dynamic loads acting on a structure based on impulse response of the structure, also referred to as the system Markov parameters, and structure response measured at optimally placed sensors on the structure. Inverse Markov parameters are computed from the forward Markov parameters using a linear prediction algorithm and have the roles of input and output reversed. The applied loads are then reconstructed by convolving the inverse Markov parameters with the system response to the loads measured at optimal locations on the structure. The structure essentially acts as its own load transducer. It has been noted that the computation of inverse Markov parameters, like most other inverse problems, is ill-conditioned which causes their convolution with the measured response to become quite sensitive to errors in system modeling and response measurements. The computation of inverse Markov parameters (and thereby the quality of load estimates) depends on the locations of sensors on the structure. To ensure that the computation of inverse Markov parameters is well-conditioned, a solution approach, based on the construction ofD-optimal designs, is presented to determine the optimal sensor locations such that precise load estimates are obtained.
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Goršič, Maja, Boyi Dai i Domen Novak. "Load Position and Weight Classification during Carrying Gait Using Wearable Inertial and Electromyographic Sensors". Sensors 20, nr 17 (2.09.2020): 4963. http://dx.doi.org/10.3390/s20174963.
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Lifting and carrying heavy objects is a major aspect of physically intensive jobs. Wearable sensors have previously been used to classify different ways of picking up an object, but have seen only limited use for automatic classification of load position and weight while a person is walking and carrying an object. In this proof-of-concept study, we thus used wearable inertial and electromyographic sensors for offline classification of different load positions (frontal vs. unilateral vs. bilateral side loads) and weights during gait. Ten participants performed 19 different carrying trials each while wearing the sensors, and data from these trials were used to train and evaluate classification algorithms based on supervised machine learning. The algorithms differentiated between frontal and other loads (side/none) with an accuracy of 100%, between frontal vs. unilateral side load vs. bilateral side load with an accuracy of 96.1%, and between different load asymmetry levels with accuracies of 75–79%. While the study is limited by a lack of electromyographic sensors on the arms and a limited number of load positions/weights, it shows that wearable sensors can differentiate between different load positions and weights during gait with high accuracy. In the future, such approaches could be used to control assistive devices or for long-term worker monitoring in physically demanding occupations.
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Gupta, Deepak K., i Anoop K. Dhingra. "Dynamic Programming Approach to Load Estimation Using Optimal Sensor Placement and Model Reduction". International Journal of Computational Methods 15, nr 08 (31.10.2018): 1850071. http://dx.doi.org/10.1142/s0219876218500718.
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A time-domain technique for estimating dynamic loads acting on a structure from structural response measured experimentally at a finite number of optimally placed sensors on the structure is presented. The technique relies on an existing solution method based on dynamic programming, which consists of a backward (inverse) time sweeping phase followed by a forward time sweeping phase. The dynamic programming method of load identification, similar to all other inverse methods, suffers from ill-conditioning. Small variations (noise) in response measurements can cause large errors in load estimates. The condition of the inverse problem, and hence the quality of load estimates, depends on the locations of sensors on the structure. There can be a large number of locations on a structure where sensors can potentially be mounted. A D-optimal design algorithm is used to arrive at optimal sensor locations such that the condition of the inverse problem is improved and precise load estimates are obtained. Another major limitation of the dynamic programming technique is that the computation time increases dramatically as the model size increases. To deal with this shortcoming, a technique based on Craig–Bampton model reduction is also proposed in this paper. Numerical results illustrate the effectiveness of the proposed technique in accurately recovering the loads imposed on discrete as well as continuous systems.
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Anderson, William D., Sydney L. M. Wilson i David W. Holdsworth. "Development of a Wireless Telemetry Sensor Device to Measure Load and Deformation in Orthopaedic Applications". Sensors 20, nr 23 (27.11.2020): 6772. http://dx.doi.org/10.3390/s20236772.
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Due to sensor size and supporting circuitry, in-vivo load and deformation measurements are currently restricted to applications within larger orthopaedic implants. The objective of this study is to repurpose a commercially available low-power, miniature, wireless, telemetric, tire-pressure sensor (FXTH87) to measure load and deformation for future use in orthopaedic and biomedical applications. The capacitive transducer membrane was modified, and compressive deformation was applied to the transducer to determine the sensor signal value and the internal resistive force. The sensor package was embedded within a deformable enclosure to illustrate potential applications of the sensor for monitoring load. To reach the maximum output signal value, sensors required compressive deformation of 350 ± 24 µm. The output signal value of the sensor was an effective predictor of the applied load on a calibrated plastic strain member, over a range of 35 N. The FXTH87 sensor can effectively sense and transmit load-induced deformations. The sensor does not have a limit on loads it can measure, as long as deformation resulting from the applied load does not exceed 350 µm. The proposed device presents a sensitive and precise means to monitor deformation and load within small-scale, deformable enclosures.
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Du, H., i B. E. Klamecki. "Force Sensors Embedded in Surfaces for Manufacturing and Other Tribological Process Monitoring". Journal of Manufacturing Science and Engineering 121, nr 4 (1.11.1999): 739–48. http://dx.doi.org/10.1115/1.2833131.
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The measurement of tooling-workpiece interface forces is needed for process design, process modeling and analysis and process monitoring for control. One approach to measuring local interface loads with minimal disturbance of the surface and process is to embed sensors in the surface below the surface region of interest. Small piezoelectric sensing elements were cast into surfaces and their ability to measure loads applied normal to the surfaces was assessed. Sensor outputs were analyzed in terms of sensor depth below the surface, distance along the surface from the load location to the sensor location and sensor to sensor spacing. A mechanical model of the sensor-surface system was developed which predicted sensor output. The use of this sensing concept and type of sensor was demonstrated in strip drawing tests. Using temperature compensated sensors, workpiece holddown force was measured in tests during which drawbead penetration was varied.
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Ramos, Daniel, Brigida Teixeira, Pedro Faria, Luis Gomes, Omid Abrishambaf i Zita Vale. "Use of Sensors and Analyzers Data for Load Forecasting: A Two Stage Approach". Sensors 20, nr 12 (22.06.2020): 3524. http://dx.doi.org/10.3390/s20123524.
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The increase in sensors in buildings and home automation bring potential information to improve buildings’ energy management. One promissory field is load forecasting, where the inclusion of other sensors’ data in addition to load consumption may improve the forecasting results. However, an adequate selection of sensor parameters to use as input to the load forecasting should be done. In this paper, a methodology is proposed that includes a two-stage approach to improve the use of sensor data for a specific building. As an innovation, in the first stage, the relevant sensor data is selected for each specific building, while in the second stage, the load forecast is updated according to the actual forecast error. When a certain error is reached, the forecasting algorithm (Artificial Neural Network or K-Nearest Neighbors) is trained with the most recent data instead of training the algorithm every time. Data collection is provided by a prototype of agent-based sensors developed by the authors in order to support the proposed methodology. In this case study, data over a period of six months with five-minute time intervals regarding eight types of sensors are used. These data have been adapted from an office building to illustrate the advantages of the proposed methodology.
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Khullar, Monika, i Parvinder Singh. "An Energy Efficient Optimal Load Sharing Technique in WSN". International Journal of Advanced Research in Computer Science and Software Engineering 7, nr 7 (30.07.2017): 279. http://dx.doi.org/10.23956/ijarcsse.v7i7.139.
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Wireless sensor networks have become increasingly popular for environmental and activity monitoring, such as temperature, pollution, parking space, traffic, and crowd monitoring. Mobile users can collect and visualize sensing data by communicating with wireless sensors along their walks using Bluetooth or NFC. They can also share the sensing data on the Internet through 3G or WiFi connectivity. Nevertheless, mobile users may not be able to collect all the data from the sensors due to limited contact times and batteries. In this research a review of different techniques to be used for clustering in WSN.
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Kumar Kashyap, Pankaj, Sushil Kumar, Upasana Dohare, Vinod Kumar i Rupak Kharel. "Green Computing in Sensors-Enabled Internet of Things: Neuro Fuzzy Logic-Based Load Balancing". Electronics 8, nr 4 (29.03.2019): 384. http://dx.doi.org/10.3390/electronics8040384.
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Energy is a precious resource in the sensors-enabled Internet of Things (IoT). Unequal load on sensors deplete their energy quickly, which may interrupt the operations in the network. Further, a single artificial intelligence technique is not enough to solve the problem of load balancing and minimize energy consumption, because of the integration of ubiquitous smart-sensors-enabled IoT. In this paper, we present an adaptive neuro fuzzy clustering algorithm (ANFCA) to balance the load evenly among sensors. We synthesized fuzzy logic and a neural network to counterbalance the selection of the optimal number of cluster heads and even distribution of load among the sensors. We developed fuzzy rules, sets, and membership functions of an adaptive neuro fuzzy inference system to decide whether a sensor can play the role of a cluster head based on the parameters of residual energy, node distance to the base station, and node density. The proposed ANFCA outperformed the state-of-the-art algorithms in terms of node death rate percentage, number of remaining functioning nodes, average energy consumption, and standard deviation of residual energy.
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Loamrat, Kraisit, Manote Sappakittipakorn i Piti Sukontasukkul. "Electrical Resistivity of Cement-Based Sensors under a Sustained Load". Advanced Materials Research 931-932 (maj 2014): 436–40. http://dx.doi.org/10.4028/www.scientific.net/amr.931-932.436.
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This research was to study the influence of a sustained load on the electrical resistivity of a cement-based sensor. The cement-based sensor in this study was made of cement paste having water to cement ratio of 0.4 with the addition of graphite powder at 2% and 4% by weight of cement and carbon fibers at 2% and 4% by volume. The sustained load was applied on the cement-based-sensor using a sustain machine to control a compressive force continually at 30% of its ultimate compressive strength for a period of 30 days. The test results showed that the sustained load induced a creep strain on the cement-based-sensor. The graphite incorporated cement-based sensor showed higher creep strain than the plain cement-based sensor while the carbon fiber cement-based sensor showed lesser. In addition, it was shown that the creep strains affect the electrical resistivity of the cement-based sensors.
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Perez-Alfaro, Irene, Daniel Gil-Hernandez, Oscar Muñoz-Navascues, Jesus Casbas-Gimenez, Juan Carlos Sanchez-Catalan i Nieves Murillo. "Low-Cost Piezoelectric Sensors for Time Domain Load Monitoring of Metallic Structures During Operational and Maintenance Processes". Sensors 20, nr 5 (7.03.2020): 1471. http://dx.doi.org/10.3390/s20051471.
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The versatility of piezoelectric sensors in measurement techniques and their performance in applications has given rise to an increased interest in their use for structural and manufacturing component monitoring. They enable wireless and sensor network solutions to be developed in order to directly integrate the sensors into machines, fixtures and tools. Piezoelectric sensors increasingly compete with strain-gauges due to their wide operational temperature range, load and strain sensing accuracy, low power consumption and low cost. This research sets out the use of piezoelectric sensors for real-time monitoring of mechanical strength in metallic structures in the ongoing operational control of machinery components. The behaviour of aluminium and steel structures under flexural strength was studied using piezoelectric sensors. Variations in structural behaviour and geometry were measured, and the load and μstrains during operational conditions were quantified in the time domain at a specific frequency. The lead zirconium titanate (PZT) sensors were able to distinguish between material types and thicknesses. Moreover, this work covers frequency selection and optimisation from 20 Hz to 300 kHz. Significant differences in terms of optimal operating frequencies and sensitivity were found in both structures. The influence of the PZT voltage applied was assessed to reduce power consumption without signal loss, and calibration to μstrains and loads was performed.
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Xiao, Huigang, Hui Li i Jinping Ou. "Self-monitoring Properties of Concrete Columns with Embedded Cement-based Strain Sensors". Journal of Intelligent Material Systems and Structures 22, nr 2 (styczeń 2011): 191–200. http://dx.doi.org/10.1177/1045389x10396573.
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Cement-based strain sensors (CBCC sensor) were fabricated by taking the advantage of piezoresistivity of CB-filled CBCC. CBCC sensors were centrally embedded into concrete columns (made with C40 and C80 concretes, respectively) to monitor the strain of the columns under cyclic load and monotonic load by measuring the resistance of CBCC sensors. The comparison between the monitored results of CBCC sensors and that of traditional displacement transducers indicates that CBCC sensors have good strain-sensing abilities. Meanwhile, CBCC sensors exhibit different failure modes that break later than C40 concrete columns, but a little earlier than C80 concrete columns. Therefore, the strength-matching principle between embedded CBCC sensors and concrete columns is proposed in this article to guarantee the sensing capacity of CBCC sensors in various concrete structures. The analytical results agree well with the experimental phenomena.
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Shohag, Md Abu S., Zhengqian Jiang, Emily C. Hammel, Lucas Braga Carani, David O. Olawale, Tarik J. Dickens, Hui Wang i Okenwa I. Okoli. "Development of friction-induced triboluminescent sensor for load monitoring". Journal of Intelligent Material Systems and Structures 29, nr 5 (15.08.2017): 883–95. http://dx.doi.org/10.1177/1045389x17721049.
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Real-time load monitoring of critical civil and mechanical structures especially dynamic structures such as wind turbine blades is imperative for longer service life. This article proposed a novel sensor system based on the proprietary in situ triboluminescent optical fiber (ITOF) sensor for dynamic load monitoring. The new ITOF sensor patch consists of an ITOF sensor network with micro-exciters integrated within a polymer matrix. The sensor patch was subjected to repeated flexural loading and produced triboluminescent emissions due to the friction between micro-exciters and ITOF sensors corresponding to each loading cycle. The friction-induced triboluminescent intensity directly depends on the loading rate, the coefficient of friction, and the applied load on patch. In general, the triboluminescent intensity increases exponentially with an increase in load. Additionally, the sensor patches comprising the coarser micro-exciters exhibited better results. Similarly, better results were achieved at higher loading rates although a threshold loading rate is required to excite the triboluminescent crystals for this sample configuration. The proposed new sensor has the ability to monitor dynamic continuous applied loads.
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Shi, Haiyan, Wanliang Wang i Ngaiming Kwok. "Energy Dependent Divisible Load Theory for Wireless Sensor Network Workload Allocation". Mathematical Problems in Engineering 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/235289.
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The wireless sensor network (WSN), consisting of a large number of microsensors with wireless communication abilities, has become an indispensable tool for use in monitoring and surveillance applications. Despite its advantages in deployment flexibility and fault tolerance, the WSN is vulnerable to failures due to the depletion of limited onboard battery energy. A major portion of energy consumption is caused by the transmission of sensed results to the master processor. The amount of energy used, in fact, is related to both the duration of sensing and data transmission. Hence, in order to extend the operation lifespan of the WSN, a proper allocation of sensing workload among the sensors is necessary. An assignment scheme is here formulated on the basis of the divisible load theory, namely, the energy dependent divisible load theory (EDDLT) for sensing workload allocations. In particular, the amount of residual energies onboard sensors are considered while deciding the workload assigned to each sensor. Sensors with smaller amount of residual energy are assigned lighter workloads, thus, allowing for a reduced energy consumption and the sensor lifespan is extended. Simulation studies are conducted and results have illustrated the effectiveness of the proposed workload allocation method.
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Gkantou, Michaela, Magomed Muradov, George S. Kamaris, Khalid Hashim, William Atherton i Patryk Kot. "Novel Electromagnetic Sensors Embedded in Reinforced Concrete Beams for Crack Detection". Sensors 19, nr 23 (26.11.2019): 5175. http://dx.doi.org/10.3390/s19235175.
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This paper investigates the possibility of applying novel microwave sensors for crack detection in reinforced concrete structures. Initially, a microstrip patch antenna with a split ring resonator (SRR) structure was designed, simulated and fabricated. To evaluate the sensor’s performance, a series of structural tests were carried out and the sensor responses were monitored. Four reinforced concrete (RC) beam specimens, designed according to the European Standards, were tested under three-point bending. The load was applied incrementally to the beams and the static responses were monitored via the use of a load cell, displacement transducers and crack width gauges (Demec studs). In parallel, signal readings from the microwave sensors, which were employed prior to the casting of the concrete and located along the neutral axis at the mid-span of the beam, were recorded at various load increments. The microwave measurements were analysed and compared with those from crack width gauges. A strong linear relationship between the crack propagation and the electromagnetic signal across the full captured spectrum was found, demonstrating the technique’s capability and its potential for further research, offering a reliable, low-cost option for structural health monitoring (SHM).
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Gao, Qingfei, Kemeng Cui, Jun Li, Binqiang Guo i Yang Liu. "Optimal layout of sensors in large-span cable-stayed bridges subjected to moving vehicular loads". International Journal of Distributed Sensor Networks 16, nr 1 (styczeń 2020): 155014771989937. http://dx.doi.org/10.1177/1550147719899376.
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To obtain the health status of long-span cable-stayed bridges, multiple sensors are applied to the health monitoring system for data collection. The optimal layout of sensors that aims to obtain as much structural information as possible with fewer sensors is important to ensure the effectiveness of the health monitoring system. Sensors are usually placed in typical locations where the structural response is obvious, and most studies utilize static response for the determination of sensor location. In fact, bridges primarily suffer the dynamic load, of which the response has a significant impact on the structural health. In this article, an optimal sensor layout method for a long-span cable-stayed bridge based on dynamic response is proposed under the consideration of vehicle–bridge coupled vibration. With vehicle load applied onto different lanes, the dynamic responses of different bridge members are obtained, and the number and the location of cable force sensors are determined according to the distribution of cable dynamic coefficient DC, and the number and the location of displacement and strain sensors are determined according to the distribution of DGD and DGM, which are the dynamic load allowance for girder deflection and bending moment, respectively. The results prove that this method can reduce the number of sensors effectively and obtain bridge state information more perfectly.
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Cumbo, Roberta, Tommaso Tamarozzi, Pavel Jiranek, Wim Desmet i Pierangelo Masarati. "State and Force Estimation on a Rotating Helicopter Blade through a Kalman-Based Approach". Sensors 20, nr 15 (28.07.2020): 4196. http://dx.doi.org/10.3390/s20154196.
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The interaction between the rotating blades and the external fluid in non-axial flow conditions is the main source of vibratory loads on the main rotor of helicopters. The knowledge or prediction of the produced aerodynamic loads and of the dynamic behavior of the components could represent an advantage in preventing failures of the entire rotorcraft. Some techniques have been explored in the literature, but in this field of application, high accuracy can be reached if a large amount of sensor data and/or a high-fidelity numerical model is available. This paper applies the Kalman filtering technique to rotor load estimation. The nature of the filter allows the usage of a minimum set of sensors. The compensation of a low-fidelity model is also possible by accounting for sensors and model uncertainties. The efficiency of the filter for state and load estimation on a rotating blade is tested in this contribution, considering two different sources of uncertainties on a coupled multibody-aerodynamic model. Numerical results show an accurate state reconstruction with respect to the selected sensor layout. The aerodynamic loads are accurately evaluated in post-processing.
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Sathyanarayana, C. N., S. Raja i H. M. Ragavendra. "Procedure to Use PZT Sensors in Vibration and Load Measurements". Smart Materials Research 2013 (30.10.2013): 1–9. http://dx.doi.org/10.1155/2013/173605.
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In situ correlation procedure is developed for electromechanically coupled PZT sensors to output the structural responses in standard engineering format, namely, displacement, strain, acceleration, and so forth. In order to implement this idea, we have used the standard sensing devices such as laser displacement sensor, strain gauge, and accelerometer. Aluminum beams and composite plate are employed in the experiments as specimens. The experimental results have shown that the structural reactions at critical locations can be monitored by a dynamically correlated PZT patch sensor, besides measuring the intensity of load in terms of acceleration. Furthermore, the influence of damage on sensor correlation has been evaluated. It is seen that the presence of damage has significantly modified the interpreted engineering parameters from the PZT patch and if they are appropriately correlated with respect to healthy structure, then the occurrence of damage related information will be ascertained. The developed sensor correlation concept therefore may be useful in load monitoring, health monitoring, and structural control applications.
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Dziadak, Bogdan. "Structural Health Monitoring System for Snow and Wind Load Measurement". Electronics 9, nr 4 (3.04.2020): 609. http://dx.doi.org/10.3390/electronics9040609.
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This article presents a system for monitoring the load caused by strong winds and snow on buildings’ roofs. An estimation of the total load on the structure is obtained by measuring the strain on the main roof girders. The system is based on a wireless sensor network structure. The measurement node uses metal strain gauges and strain sensors based on conductive carbon polymers. The application of such sensors allowed us to achieve a measurement resolution of 5.5 ustrain. The node is managed by an Atmeg8A microcontroller. The use of energy saving modes allows for a battery life of 6 months.
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Xiang, Tao, Kangxu Huang, He Zhang, Yangyang Zhang, Yinnan Zhang i Yuhui Zhou. "Detection of Moving Load on Pavement Using Piezoelectric Sensors". Sensors 20, nr 8 (22.04.2020): 2366. http://dx.doi.org/10.3390/s20082366.
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More and more researches have been carried out recently on Weigh-In-Motion (WIM) technology for solving the traffic safety problems caused by overload. In this article, we aim to study the measurement accuracy of the WIM system. Based on the electromechanical theory and elastic half-space method, we establish a theoretical model of multi-layer structure to investigate the correlation between the output voltage of the piezoelectric sensor and the applied force. In addition, we performed cyclic and moving load experiments to verify the accuracy of the analytical calculations. The load magnitude identified by this theoretical model matched the experiments very well, which shows that this model is effective for the WIM system. In addition, we proved that the load frequency is an important factor affecting the measurement accuracy of the sensor, which further enables us to design more suitable sensors for certain use scenarios.
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Ramazani, Mohammad Reza, Philip Sewell, Siamak Noroozi, Mehran Koohgilani i Bob Cripps. "Sensor Optimisation for in-Service Load Measurement of a Large Composite Panel under Small Displacement". Applied Mechanics and Materials 248 (grudzień 2012): 153–61. http://dx.doi.org/10.4028/www.scientific.net/amm.248.153.
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Current methods to estimate the behaviour of composite structures are based on trial and error or oversimplification. Normally the nonlinearities in these structures are neglected and in order to cover this inadequacy in design of composite structures, an overestimate safety factor is used. These methods are often conservative and leading to the heavier structures. A novel technique employs Artificial Neural Network (ANN) as an inverse problem approach to estimate the pressure loads experienced by marine structures applied on a composite marine panel from the strain measurements. This can be used in real-time to provide an accurate load history for a marine structure without requiring knowledge of the material properties or component geometry. It is proposed that the ANN methodology, with further research and development, could be utilised for the quantification of in-service, transient loads in real-time acting on the craft from the craft’s structural response (strain response to load). However, to fully evaluate this methodology for load monitoring of marine structures further research and development is required such as sensor optimisation. The number of sensors should be minimised to reduce the time to train the system, cost and weight. This study investigates the number of sensors required for accurate load estimation by optimising the method.
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Singh, Ravinder, i Kuldeep Singh Nagla. "Comparative analysis of range sensors for the robust autonomous navigation – a review". Sensor Review 40, nr 1 (29.10.2019): 17–41. http://dx.doi.org/10.1108/sr-01-2019-0029.
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Purpose The purpose of this research is to provide the necessarily and resourceful information regarding range sensors to select the best fit sensor for robust autonomous navigation. Autonomous navigation is an emerging segment in the field of mobile robot in which the mobile robot navigates in the environment with high level of autonomy by lacking human interactions. Sensor-based perception is a prevailing aspect in the autonomous navigation of mobile robot along with localization and path planning. Various range sensors are used to get the efficient perception of the environment, but selecting the best-fit sensor to solve the navigation problem is still a vital assignment. Design/methodology/approach Autonomous navigation relies on the sensory information of various sensors, and each sensor relies on various operational parameters/characteristic for the reliable functioning. A simple strategy shown in this proposed study to select the best-fit sensor based on various parameters such as environment, 2 D/3D navigation, accuracy, speed, environmental conditions, etc. for the reliable autonomous navigation of a mobile robot. Findings This paper provides a comparative analysis for the diverse range sensors used in mobile robotics with respect to various aspects such as accuracy, computational load, 2D/3D navigation, environmental conditions, etc. to opt the best-fit sensors for achieving robust navigation of autonomous mobile robot. Originality/value This paper provides a straightforward platform for the researchers to select the best range sensor for the diverse robotics application.
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Wibowo, Dwi Basuki, Agus Suprihanto, Wahyu Caesarendra, Slamet Khoeron, Adam Glowacz i Muhammad Irfan. "A Simple Foot Plantar Pressure Measurement Platform System Using Force-Sensing Resistors". Applied System Innovation 3, nr 3 (4.08.2020): 33. http://dx.doi.org/10.3390/asi3030033.
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Generally, there are two types of working style, i.e., some people work in sitting conditions, and the remaining work mostly in a standing position. For people working in a standing position, they can spend hours in a day doing their work standing. These people do not realize that it can cause medical issues, especially for the feet, namely biometric problems. In addition, several doctors in Indonesia are already aware of this issue and state that the biometric problems faced by those kinds of people can be predicted from the load distribution on the foot. However, the tool used by the doctors in Indonesia to measure biometric problems is not a digital tool. Therefore it is very difficult to measure and predict the biometric problems quantitatively. This study aims to develop a low-cost static load measuring device using force-sensing resistor (FSR) sensors. The measuring instrument is designed in the form of a pressure plate platform which consist of 30 FSR 402 sensors. The sensors are placed right underneath the display area of the foot, 15 sensors on the soles of the left and right feet. Ten students from the Department of Mechanical Engineering, Diponegoro University (five men and five women) were asked to stand on the platform. Each subject also measured foot length (FL) to estimate shoe size, foot area contact (FAC) for validation between genders, and foot type using the digital footprint tools. From the results of measurements obtained for the left foot in the medial mid foot area, i.e., in sensors 5 and 7, not exposed to the load, on almost all subjects except subject number 3 with a load of 0.196 kg on sensor 7. The highest average load occurs in the heel area i.e., sensor 1 measured 0.713 kg and the smallest average load occurs in the five sensors, with 0 kg. A static load gauge that is designed to be used to measure each leg area for subjects with a shoe size of 40–42 with low price to be held in hospital-orthopedic hospitals and biomechanical research centers.
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Chiang, Mei-Ling, i Tsung-Te Hou. "A Scalable Virtualized Server Cluster Providing Sensor Data Storage and Web Services". Symmetry 12, nr 12 (25.11.2020): 1942. http://dx.doi.org/10.3390/sym12121942.
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With the rapid development of the Internet of Things (IoT) technology, diversified applications deploy extensive sensors to monitor objects, such as PM2.5 air quality monitoring. The sensors transmit data to the server periodically and continuously. However, a single server cannot provide efficient services for the ever-growing IoT devices and the data they generate. This study bases on the concept of symmetry of architecture and quantities in system design and explores the load balancing issue to improve performance. This study uses the Linux Virtual Server (LVS) and virtualization technology to deploy a virtual machine (VM) cluster. It consists of a front-end server, also a load balancer, to dispatch requests, and several back-end servers to provide services. These receive data from sensors and provide Web services for browsing real-time sensor data. The Hadoop Distributed File System (HDFS) and HBase are used to store the massive amount of received sensor data. Because load-balancing is critical for resource utilization, this study also proposes a new load distribution algorithm for VM-based server clusters that simultaneously provide multiple services, such as sensor services and Web service. It considers the aggregate load of all back-end servers on the same physical server that provides multiple services. It also considers the difference between physical machines and VMs. Algorithms such as those for LVS, which do not consider these factors, can cause load imbalance between physical servers. The experimental results demonstrate that the proposed system is fault tolerant, highly scalable, and offers high availability and high performance.
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Qin, Tianhao, Mengxiang Lin, Ming Cao, Kaiya Fu i Rong Ding. "Effects of Sensor Location on Dynamic Load Estimation in Weigh-in-Motion System". Sensors 18, nr 9 (12.09.2018): 3044. http://dx.doi.org/10.3390/s18093044.
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In recent years, weigh-in-motion systems based on embedded sensor networks have received a lot of attention. However, how to improve the accuracy of multi-sensor weigh-in-motion (WIM) systems while keeping costs low remains a challenge. In this paper, a numerical simulation method is presented to analyze the relationship between sensor location and the accuracy of static weight estimation. The finite element model of a WIM system is developed, which consists of three parts: a pavement model, a moving load model and two types of sensor models. Analysis of simulation results shows that the ability of sensing dynamic load is closely related to the installation depth of sensors and pavement material. Moreover, the distance between the moving wheel and sensors has a great impact on estimating performance. Gaussian curve fitting could be used to reduce weighing error within a limited range. Our work suggests that much more attention should be paid to the design of the sensor layout of a WIM system.
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Zhang, Peng, i Kuihua Wang. "Development of a smart axial strain sensor for static load testing of foundation piles". MATEC Web of Conferences 232 (2018): 04018. http://dx.doi.org/10.1051/matecconf/201823204018.
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Sensors of stress or strain currently used in geotechnical and civil engineering applications have the disadvantage that a large quantity of measuring points would result in large bundles of cables. Based on the principle of resistive strain gauge, a type of smart sensor that supports serial communication over RS-485 is developed for the measurement of strain or stress of foundation piles, which has the benefit of good noise tolerance. All the sensors installed along a pile could share a common cable for power supply and communication, and there is no actual limits to pile length. The installation in the field is simple, convenient and efficient. The sensor has a compact structure with reliable waterproof protection. The internal measurement circuit mainly consists of a Wheatstone bridge excitation module, a signal conditioning module, a microcontroller with ADC, a precision voltage reference, and a RS-485 communication module. A group of sensors were calibrated after being assembled, and the calibration results obtained have shown their functionality and reliability.
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David, Shibin, J. Andrew, Basil Xavier, Isaac Joel Raj i R. Jennifer Eunice. "Improving Scalability and Balancing the Network Load Using Adaptive Multiparent Crossover Method in Wireless Sensor Networks". Journal of Computational and Theoretical Nanoscience 17, nr 5 (1.05.2020): 2415–20. http://dx.doi.org/10.1166/jctn.2020.8906.
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Wireless sensor network comprises of scattered sensors to sense, monitor and aggregate the sensed information. The major issue in a wireless sensor network is to balance network load and to maintain less energy consumption where multi parent crossover method is considered. Multiparent cross over method will generate offspring from parent and aims at managing the load. In this paper a comparative study of different algorithms is done where the load balancing and energy consumption issue has been resolved.
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Shi, Yun Bo, He Zhang, Jun Tang, Rui Zhao i Jun Liu. "Anti-Overload of a High-G Acceleration Sensor". Advanced Materials Research 291-294 (lipiec 2011): 3103–7. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.3103.
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High-g acceleration sensors are used in high-impact environment, the ability of resisting high-overload is demand higher requirements.In order to determine the Shock-resistibility of the sensors, tests were performed using Hopkinson bar. Analysis of the failure mechanism of the sensor.The results show that the critical load resulting in sensor failure is about 200000g. Main failure mode of the sensor chip is broken.
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Yang, Zewen, Hong Xu, Yao Huang, Jingyao Sun, Daming Wu, Xiaolong Gao i Yajun Zhang. "Measuring Mechanism and Applications of Polymer-Based Flexible Sensors". Sensors 19, nr 6 (21.03.2019): 1403. http://dx.doi.org/10.3390/s19061403.
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A new type of flexible sensor, which could maintain the deformation consistency and achieve the real-time detection of the variation in load of the measured object, was proposed in this work. According to the principle of forced assembly, PDMS was used as the substrate of sensitive components and electrodes, while carbon fiber was added as a conductive medium to prepare a polymer-based flexible sensor, which effectively overcame the deformation limitation and output instability of conventional flexible sensors due to different substrates of sensitive components and the electrode. Combined with the sensor structure and the forced assembly method, a theoretical analysis of its conductive measurement mechanism was carried out. Meanwhile, an experimental test device was designed to test and analyze the output characteristics of the flexible sensor under a static and dynamic alternating load. The results show that the flexible sensor exhibited linear output under the dynamic alternating load of 10 kN to 60 kN and frequency of 3 Hz. Peak and valley value had the same phase with the load extremes. The dynamic and static experiments show that the resistance output signal and the sensitivity was in the range of 310~624.15 Ω and 171–183 N/Ω respectively. However, due to the hysteresis of the elastic recovery of the polymer, the output repeatability of the flexible sensor under the dynamic alternating load was 5.03% and 0.78% lower than that of the static load, respectively. Combined with the static and dynamic experiments, it was verified that the polymer-based flexible sensor can maintain the same deformation characteristics with the measured object, and at the same time outputted a resistance signal with a certain mapping relationship with the applied load. The repeatability of the output signal under dynamic and static experiments was within ±7%, which can meet the measurement requirements of the fatigue life of the measured body during periodic load.
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Choi, Sang-Jin, Kwon Gyu Park, Chan Park i Changhyun Lee. "Protection and Installation of FBG Strain Sensor in Deep Boreholes for Subsurface Faults Behavior Monitoring". Sensors 21, nr 15 (30.07.2021): 5170. http://dx.doi.org/10.3390/s21155170.
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Fiber optic sensors are gradually replacing electrical sensors in geotechnical applications owing to their immunity to electrical interference, durability, and cost-effectiveness. However, additional protective measures are required to prevent loss of functionality due to damage to the sensors, cables, or connection parts (splices and/or connectors) during installation and completion processes in borehole applications. We introduce two cases of installing fiber Bragg grating (FBG) strain sensors in 1 km boreholes to monitor the behavior of deep subsurface faults. We present our fiber-reinforced plastic (FRP) forming schemes to protect sensors and splices. We also present uniaxial load test and post-completion monitoring results for assessing the effects and performance of the protective measures. The uniaxial load test and post-completion monitoring show that FBG sensors are well protected by FRP forming without significant impact on sensor performance itself and that they are successfully installed in deep boreholes. In addition to summarizing our learning from experiences, we also suggest several points for consideration to improve the applicability of FBG sensors in borehole environment of the geotechnical field.
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Lu, Shao Wei, i Huai Qin Xie. "Real-Time Monitoring and Simulating the Load Effects of Smart” CFRP- Strengthened RC Beams". Key Engineering Materials 324-325 (listopad 2006): 129–32. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.129.
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FBG sensors have excellent compatibility with CFRP sheets. It can be embedded into CFRP sheets to fabricate the “smart” CFRP. This paper conducted 4 pieces of CFRP-strengthened RC beams, and embedded FBG sensors and strain gauges on the steel, concrete and CFRP of RC beams. The simulation program of flexural load effects of RC beams is compiled based on the theory of reinforced concrete and ANSYS. The experimental results show that during the load bearing process: the compatibility is perfect between FBG sensor and CFRP; the linear relationship of FBG sensor and strain gauge is uniform; the numerical simulation results and the measuring results of strains of tensile steel and compressive concrete, the load agree well. So utilizing the smart CFRP strengthened RC structures can realize the dual function of advanced rehabilitation and real-time health monitor and evaluation.
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Nitsche, Jan, Rolf Kumme i Rainer Tutsch. "Dynamic characterization of multi-component sensors for force and moment". Journal of Sensors and Sensor Systems 7, nr 2 (7.11.2018): 577–86. http://dx.doi.org/10.5194/jsss-7-577-2018.
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Abstract. An improved set-up for the characterization of multi-component sensors for force and moment is presented. It aims at calibrating such sensors under continuous sinusoidal excitation. Special focus is put on the design of load masses and adapting elements to activate uniaxial force and moment components where possible. To identify the motion and acceleration of the load mass with 6 degrees of freedom, a photogrammetric measurement system is implemented in the existing set-up. Using the set-up described, different experiments are performed to analyse a commercial multi-component sensor and perform a parameter identification for its force components.
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Madokoro, Hirokazu, Kazuhisa Nakasho, Nobuhiro Shimoi, Hanwool Woo i Kazuhito Sato. "Development of Invisible Sensors and a Machine-Learning-Based Recognition System Used for Early Prediction of Discontinuous Bed-Leaving Behavior Patterns". Sensors 20, nr 5 (5.03.2020): 1415. http://dx.doi.org/10.3390/s20051415.
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This paper presents a novel bed-leaving sensor system for real-time recognition of bed-leaving behavior patterns. The proposed system comprises five pad sensors installed on a bed, a rail sensor inserted in a safety rail, and a behavior pattern recognizer based on machine learning. The linear characteristic between loads and output was obtained from a load test to evaluate sensor output characteristics. Moreover, the output values change linearly concomitantly with speed to attain the sensor with the equivalent load. We obtained benchmark datasets of continuous and discontinuous behavior patterns from ten subjects. Recognition targets using our sensor prototype and their monitoring system comprise five behavior patterns: sleeping, longitudinal sitting, lateral sitting, terminal sitting, and leaving the bed. We compared machine learning algorithms of five types to recognize five behavior patterns. The experimentally obtained results revealed that the proposed sensor system improved recognition accuracy for both datasets. Moreover, we achieved improved recognition accuracy after integration of learning datasets as a general discriminator.
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Lao, Steven, Hamza Edher, Utkarsh Saini, Jeffrey Sixt i Armaghan Salehian. "A Novel Capacitance-Based In-Situ Pressure Sensor for Wearable Compression Garments". Micromachines 10, nr 11 (31.10.2019): 743. http://dx.doi.org/10.3390/mi10110743.
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This paper pertains to the development & evaluation of a dielectric electroactive polymer-based tactile pressure sensor and its circuitry. The evaluations conceived target the sensor’s use case as an in-situ measurement device assessing load conditions imposed by compression garments in either static form or dynamic pulsations. Several testing protocols are described to evaluate and characterize the sensor’s effectiveness for static and dynamic response such as repeatability, linearity, dynamic effectiveness, hysteresis effects of the sensor under static conditions, sensitivity to measurement surface curvature and temperature and humidity effects. Compared to pneumatic sensors in similar physiological applications, this sensor presents several significant advantages including better spatial resolution, compact packaging, manufacturability for smaller footprints and overall simplicity for use in array configurations. The sampling rates and sensitivity are also less prone to variability compared to pneumatic pressure sensors. The presented sensor has a high sampling rate of 285 Hz that can further assist with the physiological applications targeted for improved cardiac performance. An average error of ± 5.0 mmHg with a frequency of 1–2 Hz over a range of 0 to 120 mmHg was achieved when tested cyclically.
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Khalil, Ahmed, i Nicolas Fezans. "A multi-channel $$\varvec{H}_\infty $$ preview control approach to load alleviation design for flexible aircraft". CEAS Aeronautical Journal 12, nr 2 (kwiecień 2021): 401–12. http://dx.doi.org/10.1007/s13272-021-00503-z.
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AbstractGust load alleviation functions are mainly designed for two objectives: first, alleviating the structural loads resulting from turbulence or gust encounter, and hence reducing the structural fatigue and/or weight; and second, enhancing the ride qualities, and hence the passengers’ comfort. Whilst load alleviation functions can improve both aspects, the designer will still need to make design trade-offs between these two objectives and also between various types and locations of the structural loads. The possible emergence of affordable and reliable remote wind sensor techniques (e.g., Doppler LIDAR) in the future leads to considering new types of load alleviation functions as these sensors would permit anticipating the near future gusts and other types of turbulence. In this paper, we propose a preview control design methodology for the design of a load alleviation function with such anticipation capabilities, based on recent advancements on discrete-time reduced-order multi-channel $$H_\infty $$ H ∞ techniques. The methodology is illustrated on the DLR Discus-2c flexible sailplane model.
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Rao, N. Thirupathi. "Traffic Supervision System Using Hyg12 Load Sensors". International Journal of Science and Engineering for Smart Vehicles 3, nr 1 (30.11.2019): 21–30. http://dx.doi.org/10.21742/ijsesv.2019.3.1.03.
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Kamizi, Marcos Aleksandro, Diogo Lugarini, Ruahn Fuser, Lucas Herman Negri, Jose Luis Fabris i Marcia Muller. "Multiplexing Optical Fiber Macro-Bend Load Sensors". Journal of Lightwave Technology 37, nr 18 (15.09.2019): 4858–63. http://dx.doi.org/10.1109/jlt.2019.2924142.
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Belavic, Darko, Marko Hrovat i Marko Pavlin. "Vertical thick-film resistors as load sensors". Journal of the European Ceramic Society 21, nr 10-11 (styczeń 2001): 1989–92. http://dx.doi.org/10.1016/s0955-2219(01)00157-1.
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