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Loday, Sylvie (Sylvie Johanna) 1977. "Electronic architecture and technoogy development of astronaut spaceflight load sensors". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/83679.
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Estrelinha, Emílio Gerardo. "Tele-operation of a humanoid robot using haptics and load sensors". Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11986.
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Mestrado em Engenharia MecânicaO principal objetivo desta tese é criar uma plataforma eficaz e modular para preparar o Projeto Humanoide da Universidade de Aveiro (PHUA) para o ensino tele-cinestésico. Este novo conceito de aprendizagem robótica por demonstração é neste momento a base deste projeto, onde um usuário humano tele-opera o robô em vários movimentos e tarefas de equilíbrio. Os dados recolhidos durante estas demonstrações podem ser usados em algoritmos de aprendizagem de modo a que o robô se possa mover, equilibrar e caminhar sozinho. O robô utilizado neste trabalho é uma plataforma humanoide proprietária com 27 GDL desenvolvida completamente na Universidade de Aveiro. Várias demonstrações são realizadas neste trabalho usando dados sensoriais das células de carga instaladas nos pés do robô e um dispositivo háptico para interface com o utilizador. Quatro células são colocadas em cada um dos pés dando ao robô a capacidade para sentir o chão e estimar o centro de pressão. Uma unidade de aquisição de dados foi desenvolvida para obter os sinais das células de carga. Esta unidade é capaz de ler das células e transmitir essa informação a uma frequência superior a 1000 Hz permitindo um fluxo de informação praticamente contínuo. A informação de força dos pés é então usada para gerar a realimentação de força do dispositivo que é sentida pelo utilizador como o desequilíbrio do robô. A plataforma ROS é usada para controlar os diferentes módulos de software, utilizando o próprio sistema de mensagem para comunicar entre estes, dando a este projeto várias ferramentas para posterior desenvolvimento.
The main objective of this thesis is to create an effective and modular platform to prepare the Humanoid Project of the University of Aveiro (PHUA) for tele-kinesthethic teaching. This new concept of robot learning from demonstration is now the base of this project, where a human user tele-operates the robot in various motion and balance tasks. The data gathered during this demonstrations can be used in learning algorithms so the robot can move, balance and walk on it’s own. The robot used in this work is a 27-DOF proprietary humanoid platform developed completely at the University of Aveiro. Several demonstrations are carried out using sensory data from the load cells installed in the robot’s feet and an haptic device for user interface. Four cells are placed in each foot giving the robot the ability to sense the floor and to estimate the center of pressure. A unit for data acquisition was developed to measure the load cells signals. This unit is capable of reading the cells and transmitting that information at a frequency over 1000 Hz allowing for a nearly continuous stream of information. The force information from the feet is then used to generate the force feedback in the haptic device which is felt by the human as the robot’s sense of balance. The ROS platform is used to control the different modules of software using it’s message system to communicate among them, giving this project several tools for further development.
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Amir, Amir R. (Amir Riyadh). "Design and development of advanced load sensors for the International Space Station". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46257.
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Thesis (E.A.A.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1998.Includes bibliographical references (p. 137-142).
In preparation for the construction of the International Space Station (ISS) a risk mitigation experiment was conducted to quantify the crew-induced disturbances to the microgravity environment on board a spacecraft during a long duration space flight. Achieving a microgravity environment for scientific experiments is one of the primary objectives of the ISS. While numerous measurements have been made to characterize the overall acceleratory environment on the Space Shuttle and on Mir, the contribution of astronaut motion to the disturbances was little understood. During the first phase of the ISS Program, the stay of U.S. astronauts on the Russian Orbital Complex Mir, the Enhanced Dynamic Load Sensors (EDLS) Spaceflight Experiment measured from May 1996 to May 1997 the forces and moments that astronaut exerted on the space station. Using four instrumented crew restraining and mobility devices, a handhold, two foot loops, and a touchpad, 133 hours of data was recorded during nominal crew activities and scientific experiments. The thesis gives a historical overview of the research that has been conducted to quantify the crew spacecraft interaction. A description of the EDLS experiment set-up and timeline as well as the custom-designed experiment hardware and software is provided. Due to an on-orbit failure of the original data acquisition system, a replacement computer was used to continue the experiment. The post-flight efforts to calibrate the replacement hardware, catalog the data files, and the tests to determine the condition of the sensors are presented. A cross-platform EDLS-specific software package was developed to aid in the analysis of the spaceflight data. The requirements, underlying signal processing equations, and the implementation in MATLAB are discussed. A preliminary design of advanced sensors for the ISS is developed in the thesis. While, retaining the proven strain-gage based method of sensing forces and moments, the restraining portion of the sensors was redesigned to aid astronauts better and can be easily exchanged for a different functionality. While having a volume of only 5800 cubic centimeters, the sensor electronics unit (SEU) incorporates most of the features of the original computer eight times its size. The SEU features an advanced embedded computer system and a Java-based operating system. Feedback on the loads applied can be provided in near real-time to the crew to aid the astronauts in maintaining a quiescent environment on the station during critical microgravity experiments.
by Amir R. Amir.
E.A.A.
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Sole, C. J., Caleb D. Bazyler, Ashley A. Kavanaugh, Satoshi Mizuguchi i Michael H. Stone. "Relationship between Internal and External Estimates of Training Load Using Wearable Inertial Sensors". Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/3837.
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PURPOSE: The purpose of the study was to examine the relationship between an external estimate of training load obtained from a wearable accelerometer device and perceived training load in women’s volleyball. METHODS: Participants of this study were thirteen NCAA Division I women’s volleyball players (Age: 20.3±1.2 y, height: 174.9±7.9cm, body mass: 68.1±12.7 kg). A wearable accelerometer device (Catapult Sports, MiniMaxX S4) was used to estimate external training load during volleyball practice sessions. In addition, following each session a rating of perceived exertion was obtained from each player using a 0-10 scale. Based on previously established methods, ratings of perceived exertion were then multiplied by the duration of practice in minutes to provide an estimate of internal training load. A Pearson product-moment zero order correlation coefficient was used to assess the relationship between external and internal training load estimates for each individual over eight practices. RESULTS: On average a positive relationship (r = 0.75±0.15) was found between training load estimates. Individual r values ranged from 0.39 to 0.92, with eight of the thirteen achieving statistical significance (p<0.05). CONCLUSIONS: Based on the relationships found between internal and external estimates of training load, both methods may be considered as an option for quantifying on-court training loads in NCAA women’s volleyball. However, the degree to which these estimates relate may vary by individual.
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Lu, Donghang [Verfasser], Rolf [Akademischer Betreuer] Jakoby i Mario [Akademischer Betreuer] Kupnik. "Dual-load Hybrid Detection of Water Content Using Electromagnetic and Surface Acoustic Wave Sensors / Donghang Lu ; Rolf Jakoby, Mario Kupnik". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2016. http://d-nb.info/1121206972/34.
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González, Andrea Veronica. "Redes de sensores com nodos móveis: investigando efeitos da mobilidade na cobertura de sensoriamento e no balanceamento de carga". Universidade Federal de Pelotas, 2016. http://repositorio.ufpel.edu.br:8080/handle/prefix/3295.
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A mobilidade de nodos em redes de sensores sem fio tem sido empregada para resolver problemas de comunicação através de nodos coletores de dados ou estações base móveis, ou ainda para melhorar a cobertura empregando nodos sensores móveis, que se movem para sensoriar áreas descobertas. No entanto, um dos principais desafios em redes de sensores sem fio é o consumo de energia, visto que o tempo de vida da rede depende da carga da bateria de seus nodos. Visando aumentar o tempo de vida das redes orientadas a eventos, estratégias dinâmicas de balanceamento de carga exploram a redundância nas áreas de sensoriamento dos nodos e evitam que mais de um nodo processe um mesmo evento. A mobilidade bem como o balanceamento de carga são importantes adaptações dinâmicas que podem ser empregadas para melhorar a eficiência de redes de sensores, mas o emprego integrado destas duas adaptações precisa ser investigado. Este trabalho avalia os efeitos da mobilidade de nodos sensores tanto na cobertura da rede quanto na eficiência das técnicas de balanceamento de carga empregadas em redes de sensores orientadas a eventos. No contexto deste trabalho, uma estratégia é implementada, a qual move nodos baseada na ação de forças de repulsão, visando espalhar nodos sobre a área de interesse e melhorar a cobertura da rede. O seu impacto na cobertura foi avaliado em diferentes cenários de implantação e em redes com diferentes densidades. Primeiramente, quando nodos são implantados de forma aleatória, e então, a mobilidade permite redistribuí-los e maximizar a cobertura da rede. Em um segundo momento, a estratégia é aplicada quando nodos começam a ser desativados pela descarga de suas baterias, onde a mobilidade pode minimizar o efeito da desativação de um nodo da rede. Além disso, experimentos foram realizados de forma a observar o impacto do emprego desta estratégia de mobilidade no desempenho de duas técnicas de balanceamento de carga consideradas estado-da-arte em redes de sensores sem fio orientadas a eventos. Neste trabalho foi considerado o consumo de energia que o nodo gasta com o sensoriamento, mas o consumo energético gasto com o movimento está fora do escopo.
The nodes mobility in wireless sensor networks has been employed to solve communication problems through mobile data mulling or base stations, or yet to improve coverage using mobile sensor nodes, which move to sensing uncovered areas. However, one of the main challenges in wireless sensor networks is the energy consumption, since the network lifetime depends on the node battery charge. In order to increase the lifetime of the event-oriented networks, dynamic load balancing strategies exploit redundancy in the nodes sensing areas and avoid that more than one node process the same event. Mobility as well as the load balancing are important dynamic adaptations that can be employed to improve the ef?ciency of sensor networks, but the integrated use of these two adaptations needs to be investigated. This work evaluates the effects of the sensor nodes mobility both on network coverage and on the ef?ciency of load balancing techniques used in event-oriented sensor networks. In the context of this work, an strategy has implemented, which moves nodes based on the action of repulsion forces, aiming to spread nodes over the area of interest and improve network coverage. Its impact on coverage has assessed in different deployment scenarios and networks with different densities. First, when nodes are deployed at random, then mobility allows them to redistribute and maximize the network coverage. In a second moment, the strategy is applied when nodes begin to be deactivated by the discharge of their batteries, where the mobility can minimize the effect of the deactivation of a node of the network. In addition, experiments have carried out in order to observe the impact of the use of this mobility strategy on the ef?ciency of two load balancing techniques considered state-of-the-art in event-oriented wireless sensor networks. In this work we considered the energy consumption that the node spends with the sensing, but the energy consumption spent with the movement is out of scope.
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Rodriguez, Alexander John, i alex73@bigpond net au. "Experimental Analysis of Disc Thickness Variation Development in Motor Vehicle Brakes". RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070209.123739.
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Over the past decade vehicle judder caused by Disc Thickness Variation (DTV) has become of major concern to automobile manufacturers worldwide. Judder is usually perceived by the driver as minor to severe vibrations transferred through the chassis during braking [1-9]. In this research, DTV is investigated via the use of a Smart Brake Pad (SBP). The SBP is a tool that will enable engineers to better understand the processes which occur in the harsh and confined environment that exists between the brake pad and disc whilst braking. It is also a tool that will enable engineers to better understand the causes of DTV and stick-slip the initiators of low and high frequency vibration in motor vehicle brakes. Furthermore, the technology can equally be used to solve many other still remaining mysteries in automotive, aerospace, rail or anywhere where two surfaces may come in contact. The SBP consists of sensors embedded into an automotive brake pad enabling it to measure pressure between the brake pad and disc whilst braking. The two sensor technologies investigated were Thick Film (TF) and Fibre Optic (FO) technologies. Each type was tested individually using a Material Testing System (MTS) at room and elevated temperatures. The chosen SBP was then successfully tested in simulated driving conditions. A preliminary mathematical model was developed and tested for the TF sensor and a novel Finite Element Analysis (FEA) model for the FO sensor. A new method called the Total Expected Error (TEE) method was also developed to simplify the sensor specification process to ensure consistent comparisons are made between sensors. Most importantly, our achievement will lead to improved comfort levels for the motorist.
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Lu, Kan. "Dynamics Based Damage Detection of Plate-Type Structures". University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1133818717.
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Li, Jing. "Inverse Problems in Structural Mechanics". Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/30075.
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This dissertation deals with the solution of three inverse problems in structural mechanics. The first one is load updating for finite element models (FEMs). A least squares fitting is used to identify the load parameters. The basic studies are made for geometrically linear and nonlinear FEMs of beams or frames by using a four-noded curved beam element, which, for a given precision, may significantly solve the ill-posed problem by reducing the overall number of degrees of freedom (DOF) of the system, especially the number of the unknown variables to obtain an overdetermined system. For the basic studies, the unknown applied load within an element is represented by a linear combination of integrated Legendre polynomials, the coefficients of which are the parameters to be extracted using measured displacements or strains. The optimizer L-BFGS-B is used to solve the least squares problem.
The second problem is the placement optimization of a distributed sensing fiber optic sensor for a smart bed using Genetic Algorithms (GA), where the sensor performance is maximized. The sensing fiber optic cable is represented by a Non-uniform Rational B-Splines (NURBS) curve, which changes the placement of a set of infinite number of the infinitesimal sensors to the placement of a set of finite number of the control points. The sensor performance is simplified as the integration of the absolute curvature change of the fiber optic cable with respect to a perturbation due to the body movement of a patient. The smart bed is modeled as an elastic mattress core, which supports a fiber optic sensor cable. The initial and deformed geometries of the bed due to the body weight of the patient are calculated using MSC/NASTRAN for a given body pressure. The deformation of the fiber optic cable can be extracted from the deformation of the mattress. The performance of the fiber optic sensor for any given placement is further calculated for any given perturbation.
The third application is stiffened panel optimization, including the size and placement optimization for the blade stiffeners, subject to buckling and stress constraints. The present work uses NURBS for the panel and stiffener representation. The mesh for the panel is generated using DistMesh, a triangulation algorithm in MATLAB. A NASTRAN/MATLAB interface is developed to automatically transfer the data between the analysis and optimization processes respectively. The optimization consists of minimizing the weight of the stiffened panel with design variables being the thickness of the plate and height and width of the stiffener as well as the placement of the stiffeners subjected to buckling and stress constraints under in-plane normal/shear and out-plane pressure loading conditions.Ph. D.
10
Chen, Amy. "Oceanographic Instrument Simulator". DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1585.
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The Monterey Bay Aquarium Research Institute (MBARI) established the Free Ocean Carbon Enrichment (FOCE) experiment to study the long-term effects of decreased ocean pH levels by developing in-situ platforms [1]. Deep FOCE (dpFOCE) was the first platform, which was deployed in 950 meters of water in Monterey Bay. After the conclusion of dpFOCE, MBARI developed an open source shallow water FOCE (swFOCE) platform located at around 250 meter of water to facilitate worldwide shallow water experiments on FOCE [1][2]. A shallow water platform can be more ubiquitous than a deep-water platform as shallow water instruments are less expensive (as it does not have to be designed to withstand the pressure at deep ocean depths) and more easily deployed (they can be deployed right along the coast).
The swFOCE experiment is an open source platform, and MBARI has made the plans available online to anyone interested in studying shallow water carbon enrichment. There is a gateway node what is connected to four sensor nodes within the swFOCE. In order to test the sensor node individually, an idea of designing an Oceanographic Instrument Simulator is purposed. The Oceanographic instrument simulator (OIS), described in this paper provides the means for MBARI engineers to test the swFOCE platform without attaching the numerous and expensive oceanographic instruments. The Oceanographic Instrument Simulator simulates the various scientific instruments that could be deployed in an actual experiment.
The Oceanographic Instrument Simulator (OIS) system includes the designed circuit board, Arduino Due and an SD Card shield. The designed circuit board will be connected to a computer through a USB cable, and be connected to MBARI’s swFOCE sensor node through a serial connection. When a query is given from the sensor node, the Arduino Due will parse the data given from the sensor node, search through the pre-installed data in the SD card and return the appropriate data back to the sensor node. A user can also manually set up the input current through a computer terminal window to control the simulated signals from the PCB.
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Eccles, Lee H. "PRESSURE BELT FOR WING LOADS MEASUREMENT". International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/606396.
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International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, NevadaBoeing Commercial Airplanes has used many methods in the past to measure the structural loads on the wings of its airplanes. The most recent approach is to use arrays of MEMS pressure sensors on the top and bottom surfaces of the wings. By knowing the difference in pressure between the top and bottom of the wings the structural loads on the wings can be calculated. It was decided that in order to build an array of 1100 sensors it would be necessary to condition the sensors and convert the analog output to a digital form at the site of the pressure measurement. This process was taken one step further by converting the output of the A/D converter into engineering units within the sensor module as well. The array is built using a flex circuit card in one foot sections that can be interconnected to form an array of up to 125 sensors. There is a sensor location every two inches on the flex circuit but not all locations are populated. This paper will describe not only the pressure belt but the lessons learned during the development and the implications that these lessons have for smart transducers in general.
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Nittala, Venkata Lakshmana Prasanth. "Routing algorithms for large scale wireless sensor networks". Texas A&M University, 2004. http://hdl.handle.net/1969.1/1449.
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Routing in sensor networks is a challenging issue due to inherent constraints such
as power, memory, and CPU processing capabilities. In this thesis, we assume an All
to All communication mode in an N × N grid sensor network. We explore routing
algorithms which load balance the network without compromising the shortest paths
constrain. We analyzed the Servetto method and studied two routing strategies,
namely Horizontal-Vertical routing and Zigzag routing. The problem is divided into
two scenarios, one being the static case (without failed nodes), and the other being the
dynamic case (with failed nodes). In static network case, we derived mathematical
formulae representing the maximum and minimum loads on a sensor grid, when
specific routing strategies are employed. We show improvement in performance in
load balancing of the grid by using Horizontal-Vertical method instead of the existing
Servetto method. In the dynamic network scenario, we compare the performance of
routing strategies with respect to probability of failure of nodes in the grid network.
We derived the formulae for the success-ratio, in specific strategies, when nodes fail
with a probability of p in a predefined source-destination pair communication. We
show that the Servetto method does not perform well in both scenarios. In addition,
Hybrid strategy proposed does not perform well compared to the studied strategies.
We support the derived formulae and the performance of the routing strategies with
extensive simulations.
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Tall, Hamadoun. "Load balancing in multichannel data collection wireless sensor networks". Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC006/document.
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Les Réseaux de Capteurs Sans Fil (RCSF) sont de plus en plus exploités par des applications diverses grâce à leur facilité de déploiement et d’auto-configuration. Les applications de collecte de données qui utilisent les RCSF ont souvent un profil convergecast : l’ensemble des données récoltées par tous les capteurs du réseau sont acheminées vers un puits de collecte, grâce à une communication multi-saut. Pendant l’acheminement des données des nœuds de collecte vers le puits, des goulots d’étranglement sont fréquemment observés, principalement au voisinage du puits. Cela est du à la congestion et au phénomène d’entonnoir couramment observé sur le trafic de données ayant un profile convergecast. Outre un risque accru de collision, cela entraîne le débordement des files d’attente des nœuds concernés conduisant à des pertes de données. Cette perte réduit le taux de livraison au puits entraînant une baisse du débit du réseau. Afin de réduire ces pertes et de permettre un meilleur taux de livraison au puits, le trafic doit être équitablement réparti au niveau de chaque saut pendant l’acheminement. Dans cette thèse, nous avons d’une part proposé S-CoLBA (Single channel Collaborative Load Balancing Algorithm), un protocole mono-canal de routage dynamique avec équilibrage de la charge. Sa métrique de routage est basée sur le délais moyen d’accès au medium radio par nœud. Chaque nœud choisit comme prochain saut à destination du puits, un de ses voisins ayant le délais d’accès le plus court. S-CoLBA intègre également une surveillance permanente des files d’attente des nœuds afin de prévenir la congestion et d’éviter le débordement de ces files. D’autre part, nous avons adapté S-CoLBA pour le rendre utilisable dans un réseau multicanal. Cette version du protocole s’appelle M-CoLBA (pour Mulitchannel CoLBA). M-CoLBA évite la congestion en équilibrant la charge grâce à une répartition du trafic au niveau de chaque saut du réseau. Dans un réseau multicanal, le problème de support de diffusion se pose. M-CoLBA introduit des périodes de synchronisations où tous les nœuds utilisent le même canal pour échanger les informations de routage. Ces périodes de synchronisation contribuent à allonger les délais de bout en bout des paquets. Nous avons ainsi optimisé M-CoLBA en "surchargeant" les acquittements des trames avec les informations de routage ( piggybacking) et les états des files d’attente. Cela évite de passer par des périodes de synchronisation pour diffuser ces informations. Cette version optimisée s’appelle ABORt ( Acknowledgement-Based opportunistic Routing protocol). Dans un cas de trafic de type convergecast, ABORt induit une diversité des routes prises par les données collectées, ce qui est bénéfique à la quantité de données transportées et à la robustesse de la solution. Les contributions ont été évaluées par simulation et expérimentation dans un réseau monocanal et multicanal. Les résultats montrent que nos contributions améliorent le taux de livraison des données au puits, optimisent le délais de bout en bout et réduisent la quantité de trafic de contrôle comparé à des solutions déjà existantesThe popularity of wireless sensor networks (WSNs) is increasing due to their ease ofdeployment and auto-configuration capabilities. They are used in different applica-tion domains including data collection with convergecast scenarios. In convergecast,all data collected in the network is destined to one common node usually called thesink. In case of high carried traffic load and depending on the used routing policy,this many-to-one data collection leads to congestion and queue overflow mainly innodes located near the sink. Congestion and queue overflow reduce delivery ratiothat negatively affects the network efficiency.Wireless sensor nodes are resource constrained devices with limited buffers sizeto store and forward data to the sink. Introducing multichannel communication inWSNs helps to increase the carried traffic load thanks to allowing parallel data trans-mission and reduction of contention and interference. With high traffic load, thenumber of data packets travelling from leaf nodes towards the sink becomes higher.In case the routing scheme does not balance the traffic load, it will be unfairly dis-tributed between forwarding nodes. Thus, nodes that are in part of the routing will beoverloaded while others are less used. Overloaded nodes increase the risk of conges-tion and queue overflow leading to data loss that reduces the throughput. Therefore,we need to couple the routing protocols with traffic load balancing scheme in hightraffic load network scenarios.The goal of this thesis is to propose an efficient routing solution to prevent con-gestion and queue overflow in high data rate convergecast WSNs, in such a way, tooptimize data delivery ratio at the sink node.On the one hand, we proposed a single channel traffic load balancing routingprotocol, named S-CoLBA (Single channel Collaborative Load balancing routing).It relies on data queueing delay metric and best score (according to the value of themetric) next hop neighbors to fairly distribute traffic load in per hop basis in the net-work. Since the carried traffic load increases in multichannel communication, onthe other hand, we adapted our contribution to cope with multichannel WSNs andwe named it as Multichannel CoLBA (M-CoLBA). As broadcasting information isnot straightforward in multichannel, we optimize M-CoLBA to use piggybackingscheme for routing information sharing in the network. This enhanced version iscalled ABORt for Acknowledgement-Based opportunistic Routing protocol and re-lies on ACK frames to share routing information. Doing so helps to optimize dataframe end-to-end delay and to reduce the transmitted beacons in the network. ABORtfairly distributes traffic load in the network and avoids congestion and queue over-flow.We evaluated the performance of our contributions in both simulation using Con-tiki OS Cooja simulator and experiment (only for S-CoLBA) on TelosB motes. Ob-tained results in both simulation and experiment confirm the efficiency of our routingprotocols in term of packet delivery ratio and queue overflow compared to some ex-isting routing protocols in the literature
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Bourgeois, Wilfrid. "On-line monitoring of wastewater quality using a chemical sensor array". Thesis, Cranfield University, 2002. http://dspace.lib.cranfield.ac.uk/handle/1826/7887.
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Real-time and on-line monitoring of wastewater quality is a subject of growing concern both in the United Kingdom and internationally. Global organic load parameters are traditionally used to define wastewater characteristics and to demonstrate that a wastewater treatment plant meets statutory law. However these measurements are mainly based on sample collection and retrospective analysis which can be time consuming. Existing on-line instruments remain limited by environmental factors, short lifetimes and fouling problems due to the harsh environment in which they have to be located. The recent availability of commercial sensor array instruments could offer a rapid and relatively simple technique for non-invasive monitoring.
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ANDERSSON, JOHAN, i RICKARD HÖGLUND. "Electric Load Driven Longboard". Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279809.
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This bachelor’s thesis aims to show an extensive overview of all the parts that build up an electric load driven longboard and see if a load controlled longboard can be seen as a safe, comfortable and convenient alternative to the more common remote controlled longboard. The thesis will also answer how weight can be measured on a longboard in the most effective way, what the most comfortable riding technique is and what a good motor-battery configuration to be able to travel at 30 km/h and 10 km would be. The longboard measures the weight distribution with load cells located between the deck and the trucks. An Arduino translates the input from the load cells to a certain speed and then sends it to an ODrive which controls a BLDC motor that is powered by two LiPo batteries. The results show that a load controlled longboard can very well be seen as a good alternative if right riding technique is used. The best technique is when the longboard accelerates when the rider tilts and keeps a constant speed when the rider stands straight. The best way to measure the weight is to fasten the trucks with hinges which lets the load cells register weight without anything interfering. Not all tests could be done because of Covid-19 but a measured top speed of 15 km/h with a high gear ratio is a promising result for the future when more suitable gear ratios will be tested to try to reach the goal of 30 km/h.Det här kandidatexamensarbetet strävar efter att visa en omfattande överblick på alla delar som bygger upp en elektrisk lastdriven longboard och se om en laststyrd longboard kan ses som ett säkert, komfortabelt och behändigt alternativ till den vanligare radiostyrda longboarden via handkontroll. Det här arbetet kommer också svara på hur vikt kan mätas på en longboard på ett så effektivt sätt som möjligt, vad som är den mest bekväma åkstilen och vad är en bra motor-batteri konfiguration för att kunna åka i 30 km/h och nå 10 km skulle vara. Longboarden mäter viktfördelningen med lastceller som är placerade mellan brädan och truckarna. En Arduino omvandlar indatan från lastcellerna till en specifik hastighet som den sedan skickar till en ODrive som kontrollerar en borstlös likströmsmotor som i sin tur är driven av två LiPo batterier. Resultaten visar att en laststyrd longboard kan mycket väl ses som ett bra alternativ om rätt åkstil används. Den bästa stilen är att longboarden accelererar när åkaren lutar sig och håller en konstant hastighet när åkaren står rakt. Det bästa sättet att mäta vikt är att montera truckarna på gångjärn som låter lastcellerna mäta vikt utan att något stör. Alla tester kunde inte utföras på grund av Covid-19 men en uppmätt topphastighet på 15 km/h med en hög utväxling är ett lovande resultat för framtiden när lämpligare utväxlingar kommer testas för att försöka nå målet på 30 km/h.
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White, Kevin A. "Tactical network load balancing in multi-gateway wireless sensor networks". Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/39036.
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Approved for public release; distribution is unlimited.A tactical wireless sensor network (WSN) is a distributed network that facilitates wireless information gathering within a region of interest. For this reason, WSNs are finding increased use by the Department of Defense. A challenge in the deployment of WSNs is the limited battery power of each sensor node. This has a significant impact on the service life of the network. In order to improve the lifespan of the network, load balancing techniques using efficient routing mechanisms must be employed such that traffic is distributed between sensor nodes and gateway(s). In this thesis, we study load balancing from a cross-layer point of view, specifically considering energy efficiency. We investigate the impact of deploying single and multiple gateways on the following established energy aware load balancing routing techniques: direct routing, minimum transmission energy, low energy adaptive cluster head routing, and zone clustering. Based on the node die out statistics observed with these protocols, we develop a novel, energy efficient zone clustering algorithm called EZone. Via extensive simulations using MATLAB, we analyze the effectiveness of these algorithms on network performance for single and multiple gateway scenarios and show that the EZone algorithm maximizes network lifetime and service area coverage.
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Kleerekoper, Anthony. "Distributed load balancing in many-to-one wireless sensor networks". Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/distributed-load-balancing-in-manytoone-wireless-sensor-networks(b282c4bc-e4b0-4440-9cad-57ebb28b167f).html.
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A typical sensor network is conceived as being a very large collection of low-powered, homogeneous nodes that remain static post-deployment and forward sensed data to a single sink via multi-hop communication. For these types of networks there is an inherent funnelling effect whereby the nodes that can communicate directly with the sink must collectively forward the traffic of the entire network and therefore these nodes use more energy than the other nodes. This is known as the energy hole problem because after some time, these nodes deplete their batteries and leave an energy hole cutting the sink off from the network.In this thesis two new routing protocols are proposed that aim to maximise load balancing among these most critical nodes in order to maximise lifetime. They are the first fully distributed routing protocols that are designed to generate a load balanced routing tree to mitigate the energy hole problem. The results show that the better performing of the two is capable of creating a highly balanced tree at the cost of a small increase in latency.Although there have been other fully distributed protocols that aim at a similar form of load balancing, it is proven that the approach they take cannot guarantee perfect balance among the most critical nodes even in unrealistically generous scenarios. This suggests that they are not well suited to that task and the simulation results show that the novel protocols proposed in this thesis outperform the best of the alternatives.Before these protocols are proposed, the absolute reception-based blacklisting routing strategy is shown to be more energy efficient than previously thought and indeed more efficient than the strategy that has previously been considered optimal. This result is used to strongly justify the use of the unit disk graph model in simulations of sensor networks. Additionally, the relay hole problem in sensor networks is analysed for the first time.
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Caliskanelli, Ipek. "A bio-inspired load balancing technique for wireless sensor networks". Thesis, University of York, 2014. http://etheses.whiterose.ac.uk/7030/.
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Wireless Sensor Networks (WSNs) consist of multiple distributed nodes each with limited resources. With their strict resource constraints and application-specific characteristics, WSNs contain many challenging trade-offs. This thesis is concerned with the load balancing of Wireless Sensor Networks (WSNs). We present an approach, inspired by bees’ pheromone propagation mechanism, that allows individual nodes to decide on the execution process locally to solve the trade-off between service availability and energy consumption. We explore the performance consequences of the pheromone-based load balancing approach using a system-level simulator. The effectiveness of the algorithm is evaluated on case studies based on sound sensors with different scenarios of existing approaches on variety of different network topologies. The performance of our approach is dependant on the values chosen for its parameters. As such, we utilise the Simulated Annealing to discover optimal parameter configurations for pheromone-based load balancing technique for any given network schema. Once the parameter values are optimised for the given network topology automatically, we inspect improving the pheromone-based load balancing approach using robotic agents. As cyber-physical systems benefit from the heterogeneity of the hardware components, we introduce the use of pheromone signalling-based robotic guidance that integrates the robotic agents to the existing load balancing approach by guiding the robots into the uncovered area of the sensor field. As such, we maximise the service availability using the robotic agents as well as the sensor nodes.
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Jaroo, Amer S. "Bridge Load Rating Using Dynamic Response Collected Through Wireless Sensor Networks". Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1391692831.
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Konstantinou, N. "The role of visual short term memory load in visual sensory detection". Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1335839/.
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In this thesis I established the role of Visual Short-Term Memory (VSTM) load in visual detection while comparing to the roles of perceptual load and Working Memory (WM) cognitive control load. Participants performed a short-term memory task combined with a visual detection task (as well as attention task, Chapter 2) during the memory delay. The level and type of load was varied (perceptual load, VSTM load or WM cognitive control load). Measures of detection sensitivity demonstrated that increased VSTM load and perceptual load have both resulted in impaired detection sensitivity that was of equivalent magnitude. In contrast, increased WM cognitive control load had either no effect on detection or under some conditions (when the detection task was combined with an attention task of higher priority) resulted in enhanced detection sensitivity, the opposite effect to VSTM load. The contrasting effects of different types of memory load rule out alternative accounts in terms of general task difficulty. Other interpretations in terms of changes in attention deployment, response bias, task priorities, verbal strategies, were also ruled out. These VSTM load effects lasted over delays of 4 seconds, were generalized to foveal, parafoveal and peripheral stimuli, and were shown to be predicted from estimates of the effects of load on VSTM capacity. fMRI results (Chapter 4) showed that high VSTM load reduces retinotopic V1 responses to the detection stimulus and psychophysics experiments (Chapter 5) showed that high VSTM load resulted in reduced effective contrast of the detection stimulus. These results in this thesis clarify the distinct roles of WM maintenance processes from those of WM cognitive control process in visual detection. These findings provide further support to the sensory recruitment hypothesis of VSTM, clarify previous discrepancies in WM research and extend load theory to account for the effects of VSTM load on visual detection.
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Bawaqneh, Hamdi. "Virtual Vehicle Pitch Sensor". Thesis, Linköpings universitet, Institutionen för systemteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69944.
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An indirect tire pressure monitoring system uses the wheel rolling radius as an indicator of low tire pressure. When extra load is put in the trunk of a car, the load distribution in the car will change. This will affect the rolling radius which in its turn will be confused with a change in the tire pressure. To avoid this phenomenon, the load distribution has to be estimated. In this thesis methods for estimating the pitch angle of a car and an offset in the pitch angle caused by changed load distribution are presented and when an estimate is derived, a load distribution can be derived. Alot of available signals are used but the most important are the longitudinal accelerometer signal and the acceleration at the wheels derived from the velocity of the car. A few ways to detect or compensate for a non-zero road grade are also presented. Based on the estimated offset, a difference between the front and rear axle heights in the vehicle can be estimated and compensating for the changed load distribution in an indirect tire pressure monitoring system will be possible.
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Ranganathan, Aravind. "Dynamic Forests and Load Balancing for Data Gathering in Wireless Sensor Networks". University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1276534625.
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Le, Xuan-Chien. "Improving performance of non-intrusive load monitoring with low-cost sensor networks". Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S019/document.
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Dans les maisons et bâtiments intelligents, il devient nécessaire de limiter l'intervention humaine sur le système énergétique, afin de fluctuer automatiquement l'énergie consommée par les appareils consommateurs. Pour cela, un système de mesure de la consommation électrique d'équipements est aussi nécessaire et peut être déployé de deux façons : intrusive ou non-intrusive. La première solution consiste à relever la consommation de chaque appareil, ce qui est inenvisageable à une grande échelle pour des raisons pratiques liées à l'entretien et aux coûts. Donc, la solution non-intrusive (NILM pour Non-Intrusive Load Monitoring), qui est capable d'identifier les différents appareils en se basant sur les signatures extraites d'une consommation globale, est plus prometteuse. Le problème le plus difficile des algorithmes NILM est comment discriminer les appareils qui ont la même caractéristique énergétique. Pour surmonter ce problème, dans cette thèse, nous proposons d'utiliser une information externe pour améliorer la performance des algorithmes existants. Les premières informations additionnelles proposées considèrent l'état précédent de chaque appareil comme la probabilité de transition d'état ou la distance de Hamming entre l'état courant et l'état précédent. Ces informations sont utilisées pour sélectionner l'ensemble le plus approprié des dispositifs actifs parmi toutes les combinaisons possibles. Nous résolvons ce problème de minimisation en norme l1 par un algorithme d'exploration exhaustive. Nous proposons également d'utiliser une autre information externe qui est la probabilité de fonctionnement de chaque appareil fournie par un réseau de capteurs sans fil (WSN pour Wireless Sensor Network) déployé dans le bâtiment. Ce système baptisé SmartSense, est différent de la solution intrusive car seul un sous-ensemble de tous les dispositifs est surveillé par les capteurs, ce qui rend le système moins intrusif. Trois approches sont appliquées dans le système SmartSense. La première approche applique une détection de changements de niveau sur le signal global de puissance consommé et les compare avec ceux existants pour identifier les dispositifs correspondants. La deuxième approche vise à résoudre le problème de minimisation en norme l1 avec les algorithmes heuristiques de composition Paréto-algébrique et de programmation dynamique. Les résultats de simulation montrent que la performance des algorithmes proposés augmente significativement avec la probabilité d'opération des dispositifs surveillés par le WSN. Comme il n'y a qu'un sous-ensemble de tous les appareils qui sont surveillés par les capteurs, ceux qui sont sélectionnés doivent satisfaire quelques critères tels qu'un taux d'utilisation élevé ou des confusions dans les signatures sélectionnées avec celles des autresIn smart homes, human intervention in the energy system needs to be eliminated as much as possible and an energy management system is required to automatically fluctuate the power consumption of the electrical devices. To design such system, a load monitoring system is necessary to be deployed in two ways: intrusive or non-intrusive. The intrusive approach requires a high deployment cost and too much technical intervention in the power supply. Therefore, the Non-Intrusive Load Monitoring (NILM) approach, in which the operation of a device can be detected based on the features extracted from the aggregate power consumption, is more promising. The difficulty of any NILM algorithm is the ambiguity among the devices with the same power characteristics. To overcome this challenge, in this thesis, we propose to use an external information to improve the performance of the existing NILM algorithms. The first proposed additional features relate to the previous state of each device such as state transition probability or the Hamming distance between the current state and the previous state. They are used to select the most suitable set of operating devices among all possible combinations when solving the l1-norm minimization problem of NILM by a brute force algorithm. Besides, we also propose to use another external feature that is the operating probability of each device provided by an additional Wireless Sensor Network (WSN). Different from the intrusive load monitoring, in this so-called SmartSense system, only a subset of all devices is monitored by the sensors, which makes the system quite less intrusive. Two approaches are applied in the SmartSense system. The first approach applies an edge detector to detect the step-changes on the power signal and then compare with the existing library to identify the corresponding devices. Meanwhile, the second approach tries to solve the l1-norm minimization problem in NILM with a compositional Pareto-algebraic heuristic and dynamic programming algorithms. The simulation results show that the performance of the proposed algorithms is significantly improved with the operating probability of the monitored devices provided by the WSN. Because only part of the devices are monitored, the selected ones must satisfy some criteria including high using rate and more confusions on the selected patterns with the others
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Mentink, Michael Johannes Antonius. "Measurement of bearing load in unicompartmental knee arthroplasty using an instrumented knee bearing". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:65a90ea6-77b6-49f2-9d8f-ecc4780dff81.
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The aim of this thesis was to investigate how to construct a system to measure load in a mobile unicompartmental knee replacement (UKR) bearing. In vivo loads have been measured in a total knee replacement (TKR), but with TKR the kinematics are different from those of the normal knee, whereas they are close to normal in a mobile UKR, so the loads measured by an instrumented UKR would be more representative of the normal knee. On the principle of measuring compression of an object under load, the load may be estimated. Compression measurement using a capacitive sensor was the optimal solution to measure load, based on life expectancy of the sensor and bearing integrity. A capacitive sensor within a polyethylene (UHMWPE) bearing has not been used before. The visco-elastic and temperature dependent properties of UHMWPE were determined with experiments. UHMWPE had an approximately linear response after ten minutes of applying a constant load. A temperature sensor should be used in vivo to compensate for temperature effects acting on the elastic modulus of UHMWPE. Finite element modelling demonstrated that positioning the sensor under the centre of the bearing concavity resulted in the largest capacitive change. The influence of various dimensional parameters on sensor output was simulated, and the conclusion was that the sensor only needs to be calibrated once. An electronic module inserted into a bearing had less than 5 % influence on bearing compression. Capacitive sensors were made from polyimide, using standard production methods, and embedded within a UKR bearing using the standard compression moulding process. The embedded sensor had a second order low pass frequency response, with a corner frequency of 9 Hz, twice the frequency required for typical functional loading such as gait. Physiological load signals, gait and step up/down, were applied to the bearing. The capacitance to load response was approximately linear. Load was estimated using a linear method and a dynamic method. The linear method performed best, with an accuracy of force estimation better than 90 %. In vitro tests were performed using a commercially available transceiver, two stan- dard antennas and a custom antenna, designed to be incorporated in the bearing. Wireless communication between an implanted custom antenna and an external an- tenna was shown to be feasible. Experiments were also performed that demonstrate that inductive powering of the bearing was feasible. In addition to load measurement, a proposal for dynamic measurement of the orien- tation angles of both the tibia and the femur was made. Power and volume calculations showed that it is possible to place an electronic module within the bearing. This thesis has not only demonstrated that it is feasible to make an instrumented bearing for UKR but has also provided a basic design for manufacturing.
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Ingeström, Victor, i John Hansson. "A Method for Estimating Soot Load in a DPF using an RF-based Sensor". Thesis, Linköpings universitet, Institutionen för systemteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-77970.
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The European emission standard is an EU directive which describes what emission limits car manufactures are required to meet. In order to meet these requirements car manufacturers use different techniques and components. In a modern diesel automobile a Diesel Particulate Filter (DPF) is used to gather soot from the exhausts. As soot accumulates in the DPF, the back pressure increases and the capability to hold more soot decreases. Therefore the DPF continuously needs to get rid of the stored soot. The soot is removed through a process called regeneration. In order to optimize when to perform regeneration, it is vital to know the amount of soot in the filter. A method for estimating the soot mass in a DPF using a radio frequency-based sensor has been developed. The sensor that has been studied is the Accusolve soot sensor from General Electric. A parameter study has been performed to evaluate the parameters that affects the sensor’s output. Parameters that have been studied include positioning of the sensor, temperature in the DPF, flow rate through the DPF and distribution of soot in the DPF. Different models for estimation of soot mass in the DPF has been developed and analyzed. An uncertainty caused by removing the coaxial cable connectors when weighing the DPF has been identified and methods for minimizing this uncertainty has been presented. Results show that the sensor output is sensitive to temperature, soot distribution and position, and also show some sensitivity to the flow rate. An ARX model, with only one state, is proposed to estimate the soot mass in the DPF, since it gives the best prediction of soot mass and showed good resistance to bias errors and noise in all the input signals.
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Ibrahim, Rwan. "An energy-efficient and load-balancing cluster-based routing protocol for wireless sensor networks". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119428.
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Clustering is a popular routing technique in configuring Wireless Sensor Networks (WSNs). It can determine the communications between all nodes to collect data in an efficient manner. It handles the main challenge of energy-efficiency in WSNs, and can be used to re-configure the network according to changes in the nodes' conditions. This thesis contributes to the routing in WSNs by proposing an Energy-efficient and Load-balancing Cluster-based (ELC) routing algorithm for Carrier Sense Multiple Access (CSMA)-based WSNs. In particular, both distance and residual energy are taken into consideration in developing the cluster-head selection procedure while ensuring that the network has a desired number of cluster heads. In addition to distance, cluster size is also used in formulating the cost function for cluster forming in order to balance load and energy consumption among the nodes, and hence, enhancing the network lifetime. Besides, ELC employs multi-hop inter-cluster routing based on a lowest-cost path approach that considers both energy efficiency and load balancing. Illustrative simulation results show that ELC consumes less energy and offers longer network lifetime as compared to other existing cluster-based routing algorithms such as Low-Energy Adaptive Clustering Hierarchy-Centralized (LEACH-C) protocol and Central Base Station Controlled Density Aware Clustering Protocol (CBCDACP).Le clustering est une technique de routage populaire utilisée dans la configuration d'un réseau de capteurs sans fil. Cette technique peutétablir les paramètres de communication entre tous les nœuds du réseau pour une collecte de données plus efficace. Elle traite l'obstacle principal à la performance des réseaux de capteurs sans fil, l'efficacité énergétique, et peut être utilisée dans la reconfiguration du réseau selon le changement de conditions des nœuds. La contribution de cette thèse au domaine de routage dans les réseaux de capteurs sans fil consiste dans la présentation d'un nouvel algorithme de routage à base de clustering écoénergétique et d'équilibrage de charge (en anglais, Energy-efficient and Load-balancing Cluster-based routing algorithm ou ELC) pour les réseaux de capteurs sans fil à base de accès multiple avec écoute de porteuse. Particulièrement, les critères de distance et énergie résiduelle sont pris en considération dans la formulation de la procédure de sélection des Cluster Heads (CHs) tout en garantissant que le réseau est formé en tout temps par un nombre désirable de CHs. Outre que la distance, la taille du cluster est de même utilisée dans la formulation de la fonction du coût de la formation des clusters. Ceci vise à équilibrer la répartition de charges et l'énergie des nœuds du réseau, et par conséquence, à aboutir à une plus longue durée de vie du réseau. En outre, ELC emploie une technique de routage inter-cluster avec sauts multiples qui se base sur une approche au moindre coût qui prend en considération l'efficacité énergétique et l'équilibrage de charge dans le réseau. Les simulations démontrent que ELC consomme moins d'énergie et aboutit à une plus longue durée de vie du réseau par rapport à d'autres algorithmes de routage à base de clustering comme LEACH-C et CBCDACP.
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Hernandez, Hernandez Helga Johana. "The Effect of Oregano Essential Oil on Microbial Load, Drying Kinetics and Sensory Atributes of Dried Meat". Doctoral thesis, Česká zemědělská univerzita v Praze, 2016. http://www.nusl.cz/ntk/nusl-259727.
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Microbial load can be controlled using either synthetic or natural preservatives. Particular interest has been focused on the potential application of plant essential oils as safer additives for meat. However, there is no published research on the use of essential oils during the meat drying process. This study was focused on enhancing the meat drying process. At first a value-added dried meat product by using oregano essential oil (OEO) to inhibit the growth of bacteria, and the sensorial response from assessors is presented. It was found that the application of the OEO in meat is effective in inhibiting Salmonella enteritidis and Escherichia coli. After 6 hours of drying at 55°C, 2 ml (0.038 ml l-1 air) and 1.5 ml (0.028 ml l-1 air) of OEO were considered the minimal inhibitory concentrations (MICs) against S. enteritidis and E. coli, respectively. Samples treated with 0.75 ml of OEO were more attractive for consumption compared with the control; at a higher concentration of OEO, the sensory quality of the food was affected.
Next, the effect of modified blanching treatments on the drying behaviour of beef meat was evaluated by determining moisture ratio versus time curves and the influence on sensory quality of the resulted product. The 3 treatments under investigation were (1) oil treatment (2) steam blanching and (3) hot air blanching with 3 doses of oregano essential oil (1) 1.5 ml (2) 3 ml and (3) 6 ml. Each treatment had an effect on the drying time of the beef samples, however, the dose of oregano essential oil applied did not affect the drying process. The results showed that steam blanching was very effective reducing the drying time. Meanwhile, 1.5 ml and 3 ml hot air blanching samples and 1.5 ml oil treatment samples were judged as better from sensory point of view and the respondents considered that adding oregano essential oil enriched the pleasantness of the smell.
In conclusion, a value-added dried meat product obtained by using oregano essential oil to enhance food safety received an acceptable sensorial response from consumers. Additionally, each modified blanching treatment tested influences the drying kinetics process, but the dose of oregano applied did not affect the drying process. In this sense, hot air blanching and oil treatment with the lowest dose had an acceptable sensorial response from consumers.
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Keshav, Pratish. "Optimisation of an industrial scale ball mill using an online pulp and ball load sensor". Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/16463.
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The secondary milling circuit at Waterval UG2 Concentrator had undergone a circuit change with the commissioning of the IsaMill, a horizontally stirred mill, in parallel with the secondary ball mill. The operation treats the PGM bearing UG2 ore type and produces a final concentrate enriched with PGM's. The concept was to treat the finer silicate rich fraction in the IsaMill and the coarser chromite rich fraction through the ball mill. This circuit is typical of a UG2 plant in which maximum silicate with minimal chromite breakage is targeted. As a result of the circuit change an opportunity for optimisation around the industrial scale ball mill was considered for this study. Of concern in this study were new operating conditions for the mill in the changed circuit at which improved performance could be obtained. Another objective was to investigate if a difference in breakage response for the silicate and chromite fractions could be identified for different operating conditions in the ball mill. The secondary mill at Waterval UG2 Concentrator was already fitted with an online ball and pulp load sensor, the Sensomag. The information obtained from the sensor is in the form of shoulder and toe positions for the ball and pulp filling in the rotating ball mill. The mill was surveyed at various ball filling and mill % solids conditions and information from the online sensor was used to understand the mill performance, particularly with regards to mill load behaviour. Hence a final objective was to demonstrate that the information obtained from the online sensor could be related to mill operating conditions. The sensor output was envisioned to eventually form part of the mill control philosophy. Samples were taken of the mill feed and discharge streams at the different operating conditions and analysed for grind as well as PGM and Cr₂O₃ content. The majority of the PGM's in the UG2 ore are in the silicates and thus the PGM distribution results would indicate the amount of breakage in the silicate fraction. Cr₂O₃ is used as an indicator of the chromite content in UG2 ore. In order to identify optimum mill performance the results were analysed using different measures which include general grind, particle and species distributions, reduction ratios, sieve efficiencies and specific energy. By comparing the results the differences and limitations of certain techniques were identified. It was found that the mill performance varied at different operating conditions. The optimum ball filling was found to be around 30%, which is similar to site operational target. The optimal % solids for this mill however seems to be higher than what the mill is typically operated at. No peak in % solids for mill performance was obtained. Scope exists to determine how far from the investigated maximum of 75% solids (by mass) does the optimum in-mill density lie for this mill. Thus new optimum conditions in terms of % solids do exist for the mill in the modified circuit. Results also showed that the size reduction of the silicates increased with an increase in mill % solids and ball filling degree. For chromite, the mill % solids did not appear to have any effect at low ball fillings, but a slight shift was observed at the higher ball fillings tested. The trend suggests that the size reduction of both silicates and chromite increased with an increase in ball filling, albeit at different rates. Finally, the test work has demonstrated that the online sensor outputs can be related to mill performance. Differences in shoulder and toe positions for the ball and pulp loads were distinct between operating conditions. Improved grind performance was observed at conditions that resulted in lower free pulp angles. Thus the sensor could be used as a control tool to identify and maintain optimum mill operational conditions. The Sensomag should be incorporated into a mill controller that looks at more than just mill ball filling. Conditions that result in optimum mill efficiency can be identified and the mill may be controlled using the sensor data. It is recommended that the mill continue to be run at 30% ball filling and at higher mill % solids than the maximum reached in this work.
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Bysice, Jason. "In-Situ Measurement of Wind Loads for Roof Edge Metal Configurations". Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33002.
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The role of a roof on any building is to separate the interior environment of the building from the exterior environment, thereby making it a crucial component of the building design. Metal roof edges are the first line of defense against wind-induced loads on the roof system; however, data on the nature of these loads acting on the roof edge system is scarce. Previous studies with field measurements of wind pressure acting on the roof edge reported that metal flashings experienced negative pressure. These findings suggest that current building codes in North America (i.e. NBCC and ASCE codes) do not accurately identify wind design loads acting on roof edge systems. The Roof Edge Systems and Technologies (REST) project is a consortium of academia, government and roof industries, which was created to develop testing protocols and design guidelines for roof edges. The work presented in this thesis contributes to the collection and analysis of wind loads acting on metal roof edges, which were installed on the Canada Post building in Vancouver, Canada. The thesis presents the findings and analysis of the measured wind-induced pressure acting on all surfaces of three different edge configurations, namely the Anchor Clip Configuration (ACC), Continuous Cleat Configuration (CCC) and Discontinuous Cleat Configuration (DCC). The analysis showed the presence of negative pressure acting on all three faces of the configurations, in which the type of configuration had minimum effect on the magnitude and nature of the wind-induced loads. Furthermore, the top face of the edge configurations was found to experience the highest suction, and the front face of the edge coping was subjected to a net outward suction force due to the combination of the suction experienced by the coping front face and the positive pressure acting on the cleat. Comparison of these results with current NBCC and ASCE building codes highlight a need to update these codes in order to adequately design metal roof edges against wind action.
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Chytil, Jan. "Statická zatěžovací zkouška nosné konstrukce". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227811.
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Subject of the thesis is experimental verification of load capacity of construction for storage coal by using load test. In the first part, the analysis of sorts of load tests is made and its execution in causality with standard regulations. Further possible options of bringing test load are described and also the method of evaluation of static load test. Second part looks into the analysis of means of measurement which can be used to determine required quantity. Final part is dedicated to realization and evaluation of the load test on material construction followed by comparison of experimental values with values established on a model of construction created by using computing program.
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Hult, Axel, i Chang Daniel Munguia. "Smartphone Acquisition and Online Visualization of IMU and EMG Sensor Data for Assessment of Wrist Load". Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231304.
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Work-related musculoskeletal disorders constitutes a substantial burden for society, generating individual suffering and financial costs. Quantifying the musculoskeletal stress and establishing exposure-response relationships is an important step in facing this problem. Observational methods for assessing exposure in the field of ergonomics have shown poor results, and the technical measurement methods that exists are often complicated to use which limits their scope to scientific purposes. This work describes the development of a prototype measurement system aimed to simplify ambulatory measurements of musculoskeletal load, specifically aimed at the wrist and hand. Wearable sensors including Inertial Measurement Units (IMU:s) and Electromyography (EMG) were connected to a smartphone and used for measuring wrist movement and forearm muscle activity. Data sampled in the smartphone was stored online in a cloud database, and a webapplication was developed to visualize work-load exposure. Testing under controlled conditions indicated that muscular rest can be measured and classified according to suggested risk thresholds. Accurate angular measurements were difficult to implement because of lacking inter-sensor alignment in the horizontal plane, as well as uncertainties in the Bluetooth protocol. Future work should focus on the IMU:s and look to further develop a method of correcting the relative angle error, as well as investigating accurate time synchronization of the two sensors.Alternatively, deriving angular velocities directly from the IMU gyroscopes could be investigated.
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Opperman, Roedolph A. (Roedolph Adriaan). "Enhanced dynamic load sensor for the International Space Station : design, development, musculoskeletal modeling and experimental evaluation". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122498.
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Thesis: Ph. D. in Aerospace Systems Engineering, Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 163-179).
Prolonged exposure of a vertebrate musculoskeletal system to the microgravity environment of space leads to a reduction in bone mineral density, muscle mass, strength and endurance. Such deconditioning may impede critical astronaut activities and presents an increased injury risk during flight and when exposed to increased gravity like that of Earth or Mars. Exercise countermeasures are used extensively on the International Space Station to mitigate musculoskeletal deconditioning during long duration spaceflight missions. Despite vigorous exercise protocols, bone loss and muscle atrophy are often observed even when countermeasures are in effect. As a first step in understanding the mechanisms of injury and how on-orbit exercise countermeasures compare to those on the ground, an accurate load sensing system is needed to collect ground reaction force data in reduced gravity.
To date, no means of continuous, high resolution biomechanical force data collection and analysis has been realized for on-orbit exercise. Such a capability may advance the efficiency of these systems in mitigating the incidence of bone and muscle loss and injury risk by quantifying loading intensity and distribution during exercise in microgravity, thus allowing for cause-effect tracking of ISS exercise regimes and biomechanics. By measuring these forces and moments on the exercise device and correlating them with the post-flight fitness of crewmembers, the efficacy of various exercise devices may be assessed. More importantly, opportunities for improvement, including optimized loading protocols and lightweight exercise device designs will become apparent.
The overall goal of this research effort is to improve the understanding of astronaut joint loading during resistive exercise in a microgravity environment through the use of rigorous quantitative dynamic analysis, simulation and experimentation. This is accomplished with the development and evaluation of a novel, self-contained load sensing system. The sensor assembly augments existing countermeasures and measures loads imparted by the crew during exercise. Data collected with this system is used to parameterize a unique musculoskeletal model which is then used to evaluate associated joint reaction forces generated during exercise. The effects of varying body posture and load application points on joint loading were investigated and recommendations for enhancing on-orbit exercise protocols that mitigate both injury and deconditioning are discussed.
By validating the sensor and modeling joint loading during on-orbit exercise as described herein, a unique contribution is made in expanding NASA's capability to continuously record and quantify crew loading during exercise on ISS. Data obtained through the system is used to characterize joint loading, inform and optimize exercise protocols to mitigate musculoskeletal deconditioning and may aid in the design of improved, lightweight exercise equipment for use during long-duration spaceflight, including future missions to Mars.
"This research effort was supported by a NASA Phase I Small Business Innovation Research (SBIR) contract awarded to Aurora Flight Sciences Corporation with MIT as subcontractor. The contract period of performance spanned from June 2014 through August 2016. Contract number: 2012-11 NNX14CS55C"--Page 6
by Roedolph Adriaan Opperman.
Ph. D. in Aerospace Systems Engineering
Ph.D.inAerospaceSystemsEngineering Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
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He, Jing S. "Connected Dominating Set Based Topology Control in Wireless Sensor Networks". Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/cs_diss/70.
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Wireless Sensor Networks (WSNs) are now widely used for monitoring and controlling of systems where human intervention is not desirable or possible. Connected Dominating Sets (CDSs) based topology control in WSNs is one kind of hierarchical method to ensure sufficient coverage while reducing redundant connections in a relatively crowded network. Moreover, Minimum-sized Connected Dominating Set (MCDS) has become a well-known approach for constructing a Virtual Backbone (VB) to alleviate the broadcasting storm for efficient routing in WSNs extensively. However, no work considers the load-balance factor of CDSsin WSNs. In this dissertation, we first propose a new concept — the Load-Balanced CDS (LBCDS) and a new problem — the Load-Balanced Allocate Dominatee (LBAD) problem. Consequently, we propose a two-phase method to solve LBCDS and LBAD one by one and a one-phase Genetic Algorithm (GA) to solve the problems simultaneously.
Secondly, since there is no performance ratio analysis in previously mentioned work, three problems are investigated and analyzed later. To be specific, the MinMax Degree Maximal Independent Set (MDMIS) problem, the Load-Balanced Virtual Backbone (LBVB) problem, and the MinMax Valid-Degree non Backbone node Allocation (MVBA) problem. Approximation algorithms and comprehensive theoretical analysis of the approximation factors are presented in the dissertation.
On the other hand, in the current related literature, networks are deterministic where two nodes are assumed either connected or disconnected. In most real applications, however, there are many intermittently connected wireless links called lossy links, which only provide probabilistic connectivity. For WSNs with lossy links, we propose a Stochastic Network Model (SNM). Under this model, we measure the quality of CDSs using CDS reliability. In this dissertation, we construct an MCDS while its reliability is above a preset applicationspecified threshold, called Reliable MCDS (RMCDS). We propose a novel Genetic Algorithm (GA) with immigrant schemes called RMCDS-GA to solve the RMCDS problem.
Finally, we apply the constructed LBCDS to a practical application under the realistic SNM model, namely data aggregation. To be specific, a new problem, Load-Balanced Data Aggregation Tree (LBDAT), is introduced finally. Our simulation results show that the proposed algorithms outperform the existing state-of-the-art approaches significantly.
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Czerwek, Martin. "Experimentální a numerická analýza externího zesílení železobetonového prvku namáhaného ohybem". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265545.
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Design and manufacture of reinforced concrete beams for laboratory testing. Implementation of selected tests of mechanical properties for selected elements. Experimental analysis of reinforced concrete beams in the laboratory. Creating a numerical model in the software ATENA 2D. Graphic processing of numerical and experimental analysis and comparison.
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Li, Dongsheng [Verfasser]. "Load dependent sensor placement method based on representative least squares : applications in structural health monitoring / Dongsheng Li". Aachen : Shaker, 2012. http://d-nb.info/1069048461/34.
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Lesho, Jeffrey Carl. "Embedded damage sensor using triboluminescence as a transduction mechanism for detecting failure of a material under load". Available to US Hopkins community, 2002. http://wwwlib.umi.com/dissertations/dlnow/3068181.
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Demba, Susanne. "Sensor-based detection of the teat load caused by a collapsing liner using a pressure-indicating film". Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18564.
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Ziel der Arbeit war es zum Einen die Eignung der Messung statischer Drücke in unterschiedlichen Größenordnungen mit Hilfe von roter Farbdichtevariation zur direkten Messung des Druckes zwischen Zitze und Zitzengummi beim Melken zu testen. Zum Anderen wurden verschiedene Einflussfaktoren auf diesen Druck analysiert. Dafür wurden Untersuchungen im Versuchsmelkstand unter der Verwendung verschiedener Zitzenmodelle durchgeführt. Der Einfluss verschiedener Anlagenvakua, Pulsationsraten, Pulsphasenverhältnisse und Zitzengummis auf die Zitzenbelastung wurde umfangreich analysiert.
Es wurde festgestellt, dass sich die getestete Methode zur direkten Messung des Druckes zwischen Zitze und Zitzengummi eignet. Des Weiteren konnte ein signifikanter Einfluss aller getesteten Faktoren nachgewiesen werden. Die Zitzenbelastung beim Melken nimmt mit ansteigendem Anlagenvakuum, ansteigender Pulsationsrate und ansteigendem Phasenverhältnis zu. Die technischen Eigenschaften eines Zitzengummis, vor allem aber die Form des Zitzengummischaftes, unterscheiden sich signifikant hinsichtlich des von ihnen applizierten Druckes auf die Zitze. In allen Untersuchungen wurde der größte Druck auf das Zitzenende ausgeübt.The aim of the present thesis was to test whether the measurement of static pressure distribution and magnitude with the aid of red color density variation is appropriate to directly measure the teat load caused by a collapsing liner and to identify different factors influencing this load. Therefore, investigations were carried out in a laboratory milking parlor using different artificial teats. The influence of the machine vacuum, the pulsation rate, the pulsation ratio, and the liner type were analyzed. The present investigations showed that the tested method is appropriate to directly measure the teat load due to liner collapse. A significant effect of all tested factors could be found as well. The higher the machine vacuum, pulsation rate, and pulsation ratio, the higher the teat load caused by a collapsing liner. The technical characteristics of a liner, especially the shape of the barrel, differ significantly with regard to the teat load. In all investigations more pressure was applied to the teat end.
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Yu, Chen. "SCHEDULING AND RESOURCE MANAGEMENT FOR COMPLEX SYSTEMS: FROM LARGE-SCALE DISTRIBUTED SYSTEMS TO VERY LARGE SENSOR NETWORKS". Doctoral diss., Orlando, Fla. : University of Central Florida, 2009. http://purl.fcla.edu/fcla/etd/CFE0002907.
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Darden, Kelvin S. "Smart Microgrid Energy Management Using a Wireless Sensor Network". Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404560/.
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Modern power generation aims to utilize renewable energy sources such as solar power and wind to supply customers with power. This approach avoids exhaustion of fossil fuels as well as provides clean energy. Microgrids have become popular over the years, as they contain multiple renewable power sources and battery storage systems to supply power to the entities within the network. These microgrids can share power with the main grid or operate islanded from the grid. During an islanded scenario, self-sustainability is crucial to ensure balance between supply and demand within the microgrid. This can be accomplished by a smart microgrid that can monitor system conditions and respond to power imbalance by shedding loads based on priority. Such a method ensures security of the most important loads in the system and manages energy by automatically disconnecting lower priority loads until system conditions have improved. This thesis introduces a prioritized load shedding algorithm for the microgrid at the University of North Texas Discovery Park and highlight how such an energy management algorithm can add reliability to an islanded microgrid.
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Li, Chun-Yi, i 李俊儀. "Load-Balancing Deployment of Sensors in Multi-sink Wireless Sensor Networks". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/44833598034409689841.
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碩士玄奘大學
資訊管理學系碩士班
99
A multi-sink wireless sensor network (WSN) is composed of a large number of sensors deployed in a wide area and there are some special sensors referred as sinks which play the role of data collector. Sinks are connected to internet so that they can forward data to the data collecting server. Thus each sensor can forward the information they sensed to any one of these sinks. Since sensors located in different positions might bear different communication responsibilities, e.g. forwarding the data generated by some other sensors, the loading or energy consumption of each sensor in network is heterogeneous such that some might die earlier than the others causing bottleneck in the network. In this case, data from sensors might not be delivered successfully to the sinks. In this paper, we evaluate the corresponding energy consumption as well as the load distribution of sensors deployed uniformly in multi-sink WSN by taking the effect of data compression into consideration. With the knowledge of load distribution of network, we will find that sensors located not only near around the sinks but also in the forwarding paths from the farthest sensor to the sinks would consume more energy. A descent selection method is proposed to leverage the loading of sensors in the longest forwarding path. Moreover, deploying sensors in multi-sink WSN by density control to balance the loading of sensors in different tiers would be effectively prolong the network lifetime and increase the successful data delivery as possible. Analytic and simulation results show the conclusions that the data delivery and survival ratesis significantly improved by the proposed methods.
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Kuo, Tzu-Yao, i 郭子嶢. "Bed Exit Behavior Recognition and Prediction Using Load Cell Sensors". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/zp9f64.
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碩士國立臺北科技大學
電子工程系
106
Fall is one of the most common injury incident reported in hospitals and nursing home. Most of falls occur when the patients or elderly try to get off the bed after they wake up. Because of the shortage of staff and resources, nurses cannot always provide the assistance in time. As a result, it is common for patients and elderly to fall off the bed due to being alone in these places. In this research, we present a bed exit behavior recognition and prediction system. The system comprises four load cell sensors installed under the legs of bed with stands. Load cell itself can detect the pressure changes generated by the patient or the elderly in the bed. The system uses k-means++ algorithm to cluster bed exit actions and the hidden Markov model (HMM) to establish the association between different actions to perform bed exit behavior recognition and prediction. The experimental results showed the precision of four different posture: lying on bed, sitting on bed, sitting on edge of bed, and leaving the bed with 87%, 90%, 90%, and 99%, respectively. Furthermore, we use load cell sensor to distinguish a new action: turning waist on bed. Compares to the posture of sitting at the edge of bed, this new action can achieve earlier recognition of patient leaving the bed than using the action of sitting at the edge of bed. As a result, turning waist on bed, can help the system to send earlier alarm to nurses. Nurses can prevent patients fall. The recall and precision of bed exit prediction was 98.59% and 94.24% respectively. These results show that the proposed system is capable of providing early alarm for medical personnel to prevent patients from falls.
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Hung, Chien-Chun, i 洪健淳. "An Energy-Efficient Opportunistic Routing for Load-Balancing in Wireless Sensors Networks". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/96896933163852805595.
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碩士國立臺灣大學
資訊工程學研究所
97
Opportunistic routing has been widely approved because of its throughput improvement for wireless mesh networks; however, few researches focus on transforming its benefit into realizing energy efficiency for wireless sensor networks (WSNs). We notice that two common issues in fixed-path routing schemes, including single-path routing or multi-path routing, are that (1) a path may traverse through a fixed set of sensors, draining out their energy, and (2) packet retransmission over an unreliable link of any fixed-path may consume energy significantly. In this paper, we exploit two natural advantages of opportunistic routing, i.e., path diversity and the improvement of transmission reliability, to develop a distributed routing scheme (EFFORT) for prolonging the network-lifetime of a WSN. Unlike prior works on minimizing transmission delay in opportunistic routing, we propose a metric (called OEC) that assists each sensor in determining a suitable forwarding set for reducing the damage to the lifetime caused by each forwarding, and, thus, enable EFFORT to extend the network lifetime by implementing forwarder selection and relay prioritization based on OEC. Simulation results show that EFFORT achieves network-lifetime extension, as well as energy-cost minimization as compared with other routing protocols.
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Wen-Hau, Liau. "Inhabitant Tracking and Service Provision in an Intelligent e-Home via Floor Load Sensors". 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2507200520104000.
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Liau, Wen-Hau, i 廖文豪. "Inhabitant Tracking and Service Provision in an Intelligent e-Home via Floor Load Sensors". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/41953128393955508310.
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碩士國立臺灣大學
資訊工程學研究所
93
In this thesis, we utilize the inherent identity, the weight of the inhabitants, to track the movement of the inhabitants and provide appropriate services after determining the location of the inhabitants. There are several studies on tracking inhabitants in all kinds of environments, such as RF-ID tags or Image-detection. Those approaches sometimes require the inhabitants to wear some devices or need much pre-calibration before tracking the inhabitants. Such approaches make the inhabitants feel uncomfortable while the purpose is trying to provide convenient services to the inhabitants, which is somewhat ironic. Our approach uses the floor load sensors to perceive the weight of the inhabitants and utilizes the weight to track the inhabitant, so there is no need for inhabitants to wear any devices on them, thus making the sensory floor and the tracking algorithm we adopted need less pre-setting than other approaches. The IEHS (Intelligent E-Home System) can use the location of the inhabitant to be one kind of inhabitant’s preference data. By integrating the present research results and our previous study “APPLE” system, the IEHS can provide adequate services to the inhabitants at the proper time and the proper location.
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Lu, Donghang. "Dual-load Hybrid Detection of Water Content Using Electromagnetic and Surface Acoustic Wave Sensors". Phd thesis, 2016. https://tuprints.ulb.tu-darmstadt.de/5830/1/main.pdf.
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This work focuses on water content detection both in materials and in
gases, i.e., measurements of moisture and humidity. To detect the moisture, a cavity perturbation method (CPM) is introduced to extract the relationship between permittivity and water content in material under test (MUT), which, in this application is tobacco at a single frequency. The obtained information is used as pre-knowledge for a mass flow sensor design in tobacco production. The mass flow sensor is an open cylindrical resonator that consists of two circular waveguides with different diameters. An on-sight test of the mass flow sensor is performed, and the measured weights are within a 10% discrepancy compared to the supplied weights. For the humidity measurement, a material named polyvinyl alcohol (PVA) is employed as a sensitive layer. The PVA film involves two mechanisms for humidity sensing, which are variations of electrical loading and mechanical loading with relative humidity (RH). To apply the electrical loading property, the PVA film is characterized by an interdigital capacitor (IDC) in a wide frequency range at different RHs, and the results are used to create a comprehensive model of the PVA film for computer simulation tools to predict the performance of the sensor. A wireless humidity sensor is designed to verify the PVA film model, and a good agreement between the simulation and measurement results proves the accuracy of the model. To utilize the mechanical loading property, the PVA film is loaded on surface acoustic wave (SAW) resonators. A wet chemical method of patterning the PVA film is found, and the influence of the PVA film thickness is investigated. With different patterns and thicknesses of the PVA film, humidity sensors can achieve various performances in terms of operation range, sensitivity, and quality factor. To apply both, electrical and mechanical loading properties of the PVA film for humidity sensing at the same time, a novel dual-load SAW resonator is introduced by using additional IDCs as reflectors with the PVA film loaded on top. The humidity sensor based on this novel hybrid structure extends its operating range, and shows better sensitivity and quality factor with different sensing mechanisms within certain RH ranges. A figure of merit (FoM) is defined to evaluate the sensitivity and quality factor of the sensor at the same time, and the sensing mechanism with better FoM can be selected for humidity sensing in a defined RH range.
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Huang, Kuan-Ming, i 黃寬明. "Development of Strain Gage and Fiber Bragg Grating Sensors for Nuclear Power Plant Valve Stem Load Monitoring". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/36282704594127697170.
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碩士臺灣大學
機械工程學研究所
96
During routine overhaul, the axial force and torque in each valve stem in a nuclear power plant need to be monitored. Currently, pre-formed gages on a thin metal strip are used for this purpose. These gages are expensive and cannot last until the next overhaul. The current work attempts to fabricate similar gage that are ready for field use. The detailed requirements to ensure good accuracy during fabrication are analyzed. Practical gages have been manufactured and tested. The measured results agreed well with theoretical and experimented strain measured by sticking strain gages directly to the specimens. The durability of the gage varies from 30000 to beyond 60000 loading cycles depending on the adhesive used. Possibility of using fiber Bragg grating instead of resistance strain gage has also been investigated. The latter has the advantage that it can survive ionizing radiation
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Regier, RYAN. "APPLICATION OF FIBRE OPTICS ON REINFORCED CONCRETE STRUCTURES TO DEVELOP A STRUCTURAL HEALTH MONITORING TECHNIQUE". Thesis, 2013. http://hdl.handle.net/1974/8181.
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To better manage deteriorating infrastructure, quantitative data about the performance of infrastructure assets is required. Rayleigh based distributed fibre optic strain sensing (FOS) is a technology that has the potential to offer this type of data and unlike traditional strain sensors it can measure the strain along the full length of the structure.
A series of experiments were undertaken to develop installation techniques and evaluate sensor accuracy for typical civil engineering materials: steel, concrete and reinforced concrete. The results of these experiments showed that the choice of sensing fibre and adhesive was dependent on the material being monitored. When the sensing fibre and adhesive are chosen correctly, the Rayleigh system can provide the same accuracy as a strain gauge for steel and concrete, and useful measurements can be obtained even in areas of concrete cracking.
The FOS technique was utilized to determine whether distributed strain measurements could be used to detect and quantify localized deterioration of the steel reinforcement (localized area reductions of 0-30%) at service loads. A series of specimens was tested, the sensing system was able to detect the presence of localized deterioration with embedded nylon and polyimide fibres, but the nylon fibre cannot quantify large strain gradients due to slip within the sensing fibre. The strain profiles gave insights to the failure mechanism occurring in the reinforced concrete specimens. The strain profiles for both test series indicated that the tension reinforcement was acting as a tension tie and the strain profiles suggested the presence of compressive struts indicative of an arching mechanism in the specimens.
The Black River bridge in Madoc, Ontario was instrumented with fibre optics sensors to determine whether the use of FOS is both practical and beneficial for reinforced concrete bridge assessment when compared to conventional instrumentation. The FOS showed reasonably good agreement with conventional sensors. The fibre optic strain results are used to calculate curvature, slope and displacement but careful consideration of the boundary conditions is required. The results from the fibre optic sensors can be used to show the bridge load distribution and give insights into the support conditions of the beams.Thesis (Master, Civil Engineering) -- Queen's University, 2013-08-21 11:56:53.276
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Mabood, Fazal. "Evaluating Tire Pressure Control System to Improve Productivity and Mitigate Pavement Damage". Thesis, 2008. http://hdl.handle.net/10012/3978.
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The introduction of the use of Tire Pressure Control Systems (TPCS) to improve the productivity of the Canadian trucking industry is gaining momentum. The imposition of seasonal load restrictions (SLR) on the thaw-weakened secondary roads interrupts the transportation of raw materials to processing facilities For the forestry industry in particular, this has very significant impacts on productivity and costs. FPInnovations-Feric Division (Feric) has investigated the potential for TPCS-equipped trucks to travel with full, legal loading during the SLR period without accelerating road wear and tear. The TPCS monitors and adjusts the inflation pressure of the trucks’ tires while driving and allows the operator to optimize the inflations for changes in loading, travel speed, or road quality encountered in the trip.
This thesis describes an investigation to determine whether TPCS can be used to mitigate traffic generated damage to secondary roads and also reduce the need to implement load restrictions. The project involves a partnership with the Ontario Ministry of Transportation Ontario (MTO), Forest Engineering Research Institute of Canada (FERIC), Ontario Ministry of Natural Resources (MNR) and the Centre for Pavement and Transportation Technology (CPATT) located at the University of Waterloo.
The thesis will describe the methodology, design, and instrumentation of the two test sites which are located in Dryden, Ontario and Chapleau, Ontario. In addition, repeated Portable Falling Weight Deflectometer (PFWD) testing is being carried out at these sites and the initial results of this examination and associated impacts of the environment and traffic on the road will be presented. This study also involves looking into the reliability of using the portable FWD, offering a lower cost alternative instead of the trailer mounted FWD to monitor pavement strength for the identification the SLR period. The use of innovative sensors and data collection techniques are proving to be very informative and are advancing pavement engineering knowledge. Moreover, the thesis is aimed at exploring the possibilities of achieving the current objectives of the government DOTs such as TPCS potential for addressing the timber industry in crisis, reduced road maintenance budgets, and global warming increasing road damage.
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Wu, Chun-Shen, i 吳俊伸. "Load-Aware Geographic Routingin Wireless Sensor Networks". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/81884452611777482586.
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碩士雲林科技大學
電機工程系碩士班
98
Wireless sensor network applications such as environmental monitoring and data gathering are meant to operate as long as possible. Since each wireless node has limited communication range, packets are generally delivered hop by hop, at the expense of power consumption, towards the intended destinations. However, when any intermediate node on a path has depleted its power, i.e., a hole emerges, packet delivery fails and subsequently another new route must be resolved, so as to restore packet transfer. Therefore, a well-planned routing strategy that avoids ineffective transmissions on account of holes is essential to overall network performance. This thesis presents a load-aware geographic routing scheme that allows for three determinants for each of qualified neighbor nodes on demand: residual energy, the amount of dissipated power for current transmission, and its distance away from the destination. Each neighbor node is thus associated with a score per packet; the node which scores highest becomes the next hop to forward the packet. Such a selection is done hop by hop until the packet reaches its destination. Our strategy is to prevent packets from traversing a certain set of nodes repeatedly, causing severe power drain on these nodes. Accordingly, workload is better distributed in our architecture so that holes are less likely to shape. In addition, we propose an algorithm, namely the Available Relay Block algorithm, that is performed a priori to identify which areas towards the given destination contain dead-end nodes. These identified areas are ruled out of consideration by our load-aware strategy. By doing so, our routing strategy is kept operable, despite the presence of holes, such that network lifetime can be maximized. Performance evaluation is conducted via QualNet. Simulation results indicate the effectiveness of our design and outlines several directions to work toward in the future.
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Wang, Sheng-Yuan, i 王聖淵. "Load Balancing Routing in Wireless Sensor Networks". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/93169751190161477681.
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碩士國立臺北大學
資訊工程學系
102
Routing in WSN usually focuses on balanced distribution of nodes, nodes energy balanced and optimizing routing paths to be the shortest, fewer considering traffic load balancing issues. In WSN, some nodes become bottleneck because of encountering excessive data flow. So how to balance the load of network becomes the key of design WSN routing protocol. To achieve load balancing and reduce network bottleneck in data-intensive WSN, we propose Load Balancing Routing (LBR) protocol for WSN. LBR is based on layer routing design to connect sensor nodes and SINK. LBR contains Layering Route Construction ( LRC ), Load Estimation Algorithm ( LEA ), Smooth Transmission Mechanism ( STM ) and Route Maintenance ( RM ). LRC provides multiple next-hop choices from nodes to SINK and ensures each route is shortest that makes LBR scalable, low-overhead and robust. Through the cooperation of LRC and LEA, local and global load-balancing is accomplished. STM reduces a multi-node packets transmission at short time, which provides LBR better network transmission performance. When RM detects and recovers route failures, it does not broadcasts any error message to whole network, and can quickly adapt to network topology changes. RM makes LBR enhanced robustness route. Compared with AODV and AOMDV, simulation results show LBR provides better load balancing than AOMDV and AODV. LBR also achieves better network transmission performance and route maintenance.