138 research outputs found
Structural Health Monitoring Inside Concrete and Grout Using the Wireless Identification and Sensing Platform (WISP)
This research investigates the implementation of battery-less RFID sensing platforms inside lossy media, such as, concrete and grout. Both concrete and novel grouts can be used for nuclear plant decommissioning as part of the U.S. Department of Energy’s (DOE’s) cleanup projects. Our research examines the following: (1) material characterization, (2) analytical modeling of transmission and propagation losses inside lossy media, (3) maximum operational range of RFID wireless sensors embedded inside concrete and grout, and (4) best positioning of antennas for achieving longer communication range between RFID antennas and wireless sensors. Our research uses the battery-less Wireless Identification and Sensing Platform (WISP) which can be used to monitor temperature, and humidity inside complex materials.
By using a commercial Agilent open-ended coaxial probe (HP8570B), the measurements of the dielectric permittivity of concrete and grout are performed. Subsequently, the measured complex permittivity is used to formulate analytical Debye models. Also, the transmission and propagation losses of a uniform plane wave inside grout are calculated. Our results show that wireless sensors will perform better in concrete than grout. In addition, the maximum axial and radial ranges for WISP are experimentally determined. Our work illustrates the feasibility of battery-less wireless sensors that are embedded inside concrete and grout. Also, our work provides information that can be used to optimize the power management, sampling rate, and antenna design of such sensors
Observing and Improving the Reliability of Internet Last-mile Links
People rely on having persistent Internet connectivity from their homes and
mobile devices. However, unlike links in the core of the Internet, the links
that connect people's homes and mobile devices, known as "last-mile" links, are
not redundant. As a result, the reliability of any given link is of paramount
concern: when last-mile links fail, people can be completely disconnected from
the Internet.
In addition to lacking redundancy, Internet last-mile links are vulnerable to
failure. Such links can fail because the cables and equipment that make up
last-mile links are exposed to the elements; for example, weather can cause
tree limbs to fall on overhead cables, and flooding can destroy underground
equipment. They can also fail, eventually, because cellular last-mile links can
drain a smartphone's battery if an application tries to communicate when signal
strength is weak.
In this dissertation, I defend the following thesis: By building on existing
infrastructure, it is possible to (1) observe the reliability of Internet
last-mile links across different weather conditions and link types; (2) improve
the energy efficiency of cellular Internet last-mile links; and (3) provide an
incrementally deployable, energy-efficient Internet last-mile downlink that is
highly resilient to weather-related failures. I defend this thesis by
designing, implementing, and evaluating systems
Border surveillance monitoring using Quadcopter UAV-Aided Wireless Sensor Networks
In this paper we propose a novel cooperative bordersurveillance solution, composed of a Wireless Sensor Network (WSN) deployed terrestrially to detect and track trespassers, and a set of lightweight unmanned aircraft vehicles (UAVs) in the form of quadcopters that interact with the deployed WSN to improve the border surveillance, the detection and investigation of network failures, the maintenance of the sensor network, the tracking of trespasser, the capture and transmission of realtime video of the intrusion scene, and the response to hostage situations. A heuristic-based scheduling algorithm is described to optimize the tracking mission by increasing the rate of detected trespassers spotted by the quadcopters. Together with the design of the electrical, mechanical and software architecture of the proposed VTail quadcopter, we develop in this paper powerless techniques to accurately localize terrestrial sensors using RFID technology, compute the optimal positions of the new sensors to drop, relay data between isolated islands of nodes, and wake up sensors to track intruders. The developed VTail prototype is tested to provide valid and accurate parameters’ values to the simulation. The latter is conducted to evaluate the performance of the proposed WSN-based surveillance solution
Assistive multi-sensor framework for prevention and monitoring of pressure ulcers
Pressure ulcers (PU) are injuries to the skin and soft tissues due to prolonged pressure and have a significant impact on the quality of a patient’s life. The common risk factors of PU are pressure, shearing forces, friction, moisture, temperature, and immobility. The use of low-tech and high-tech devices is effective in distributing the high pressure exerted on the patient’s body. However, patients can still develop PU because these devices do not provide any real-time information about the risk factors of PU development. With the help of sensors, smart beds are effective to monitor and prevent the development of PU but the prevalence of PU around the globe is still high due to the aging population.
In this thesis, a multi-sensor framework is developed and tested to aid in the monitoring and prevention of PU. The proposed system is able to measure, process, and store real-time information about the numerous risk factors of PU. In addition, the framework does not need to be attached to the patient’s body in order to provide extra comfort. Different experiments are conducted to test the reliability and effectiveness of the proposed system. Experimental results indicate that the system is capable to provide the rate of repositioning, temperature, and pressure distribution
Lanthorn, vol. 14, no. 23, February 19, 1981
Lanthorn is Grand Valley State\u27s student newspaper, published from 1968 to the present
A contribution to unobtrusive measurement methods for sleep monitoring based on magnetic induction technique
Sleep monitoring is of major importance for various medical areas such as the detection and treatment of sleep disorders, assessment of different medical conditions or medications' effects over sleep quality, and mortality risk assessment associated with sleep patterns in adults and children. It is a challenging area of medical problems due to both privacy issues and technical considerations. It calls for monitoring methods in which the patient's natural state is less interfered. An ideal device would be non-invasive, minimally restrictive, robust enough to compensate movements of the patients, and would operate without relying on patient's cooperation.
Non-contact methods for monitoring vital signs and physiological activities have been given lots of attention recently. In addition to the sleep monitoring, various other medical applications demand for less-obtrusive continuous respiratory and cardiac activity monitoring methods. Applications such as home health care, neonates and burned victims monitoring and applications in which using the traditional skin electrodes may worsen or disturb the conditions of the patient, call for new contact-less approaches for monitoring purposes.
This thesis focuses on the design and development of an unobtrusive, vital sign monitoring system particularly suited for long-term monitoring. The system is a low-cost, non-contact planar system designed to be placed under the bed or mattress for applications such as sleep monitoring, neonates monitoring, etc.
The system is based on the magnetic induction sensing method, designed to infer presence on the bed, breathing and cardiac activity and consists of two coils for excitation and detection. The receiver is an asymmetric planar gradiometer which has been optimized to minimize the impact of the primary magnetic field. The signal acquisition system has been designed using simple electronics to avoid ending up with a complex expensive system. Safety study indicates that the developed system is safe to be used for continuous monitoring of breathing and cardiac activity for patients, in terms of being exposed to magnetic fields. The experimental results were compared with reference signals obtained by other sensors (photoplethysmogram, respiratory pressure transducer), for benchmarking and identifying the advantages and drawbacks of the new system regarding other techniques. Experimental results confirm the suitability and safety of the sensor for long-term cardiac and respiratory monitoring. The system is able to detect respiration and cardiac activity as well as presence on the bed and changes in position.Los métodos sin contacto para monitorizar signos vitales y actividades fisiológicas reciben cada día más atención. Además de la monitorización del sueño, otras aplicaciones médicas requieren métodos de monitorización de la actividad respiratoria y cardiaca de forma continua y menos intrusiva. Aplicaciones como el cuidado de la salud en el hogar, los bebes prematuros y las víctimas de quemaduras, en las que el uso de los electrodos tradicionales sobre la piel puede empeorar o perturbar las condiciones del paciente, requieren nuevos enfoques de monitorización sin contacto. Esta tesis se centra en el diseño y desarrollo de un sistema de monitorización de signos vitales sin contacto y particularmente adecuado para la monitorización a largo plazo. El sistema es un sistema plano sin contacto de bajo coste diseñado para ser colocado bajo la cama o colchón para aplicaciones tales como monitoreo del sueño, monitoreo de recién nacidos, etc. El sistema se basa en el método de detección por inducción magnética, diseñado para inferir la presencia en la cama, la respiración y la actividad cardíaca y consiste en dos bobinas, una para excitación y otra para detección. El receptor es un nuevo gradiómetro plano asimétrico que ha sido optimizado para minimizar el impacto del campo magnético primario. El sistema de adquisición de señales ha sido diseñado utilizando una electrónica sencilla para evitar terminar con un sistema complicado y caro. Se ha realizado un estudio de seguridad, en términos de exposición a campos magnéticos, que indica que el sistema desarrollado es seguro para ser usado en la monitorización de la respiración y actividad cardiaca. Los resultados experimentales se compararon con las señales de referencia obtenidas por otros sensores (fotopletismografia y transductor de presión bajo el colchón), para realizar un benchmarking e identificación de las ventajas e inconvenientes del nuevo sistema con respecto a otras técnicas. Los resultados experimentales confirman la idoneidad y seguridad del sensor diseñado para monitorización continua y prolongada de la actividad cardiaca y respiratoria. El sistema es capaz de detectar la respiración y la actividad cardíaca, así como la presencia en la cama y los cambios de posiciónPostprint (published version
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Factors affecting reading comprehension in primary pupils
This thesis addresses the problem of 8-11 year old pupils who, although appearing to read text fluently, frequently misunderstand it. This problem was studied through Scottish school-based research using classroom materials and subjects from natural class groups. Data were collected from language assignments in daily work programmes, with response material in either written or illustrated form. Nine feasibility studies and a main study involving eighty subjects were carried out.
The effects of five variables, text, presentation mode, age, ability and geographic location, on the totals and types of miscomprehensions displayed by the subjects in directed and free-recall comprehension tasks were calculated. 'Errors' are considered to be divergences from the author's supposed meaning. It is found that the collected errors are not random but may be classified into groups. Ten types of error were identified as regularly occurring and the category system developed was validated by teachers and others involved in the field of education.
The effects of the five variables on the numbers and categories of error collected and the interactions between these variables were subjected to statistical analysis. Text and presentation mode are found to be the factors having most effect on the quantity and type of error produced. This finding is at variance with the generally accepted assumption that age, ability and possibly environment are determinants of potential pupil achievement. Miscomprehensions are discovered to be widely distributed across the ability range but they may be concealed by pupils in their pursuit of acceptable responses. The progress expected with increasing age is not always evident.
The value of the category system as a teaching tool in comprehension development across the curriculum and pupil age range is assessed and suggestions given for its use. Implications of the findings for pupil assessment procedures and classroom practice are also discussed
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