An experimental analysis of the factors which affect the sensitivity of the Ported Coaxial Cable Sensor (PCCS) system is presented. The measured response profile of the test system is compared against variations of cable separation distance, soil conductivity and permittivity, and magnetic field intensity above the transmitter cable. These experiments show that higher conductivity and permittivity of the burial medium results in a decrease in the strength of the magnetic field above the transmitter cable, and that this results in a decrease in response number. The results of these experiments are compared with the results obtained from a theoretical analysis of a simplified model. An experimentally derived relationship between cable separation distance and response number, which is valid for all soil types, can be applied to predictably minimize variations in sensitivity, resulting in a response ratio for each cell which will not exceed 3:1.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 95-100). Also available via the Internet.

Position sensing is one of the most important tasks in the industrial manufacturing of goods and materials. Position sensing can take on a variety of forms and is used in the measurement of a wide range of variables such as distance, speed, the number of revolutions per minute, orientation, identification, and in collision protection. Proximity sensors play a significant role and are used in a plethora of industries including agriculture, consumer goods, transportation, industrial processes, electrical services, medical, military and avionics. This research is aimed at improving the performance and manufacturability of inductive proximity sensors through the design and fabrication of coils using multilayer ceramic technologies common in the manufacturing of hybrid microelectronics components and circuits. As another alternative, multilayer structures utilizing polymer materials and fabrication techniques common to the printed circuit board (PCB) industry were also investigated. Manufacture of the coils utilizing ceramic and polymer materials and hybrid and PCB fabrication techniques would eliminate the problems of repeatability, and the placement and potting of the coil. The fabrication techniques also lend well to the mass production of the coils using techniques that are well established in the electronics industry. The overall result would be a planar inductor with high yield that is suitable for mass production. / Master of Science

The U.S. construction industry continues to rank as one of the most dangerous work environments when compared to other industrial sectors. Construction companies are required to record and report lagging safety leading indicators including fatalities, injuries, and illnesses. Safety leading indicators provide an opportunity to identify construction site hazards and hazardous worker behavior before a fatality, injury, or illness occurs. Further improvements are also necessary for construction safety through the use of technology. The application of advanced or emerging technologies can have a significant role in enhancing construction worker safety performance. This research seeks to report and analyze safety leading indicators, specifically near misses. Furthermore, technologies capable of providing alerts in real-time to construction equipment operators and ground workers during hazardous proximity situations are reviewed. A testing method for proximity detection and alert devices for the construction environment is presented. Operator visibility, including impacts of design components, is also measured and analyzed. One major contribution of this research is the creation of a near miss reporting program ready for implementation for construction companies. Other research contributions include understanding of impacts of design on operator visibility, scientific evaluation data of proximity sensing technology, and a test method for proximity detection and alert system deployed in the construction environment. Research findings can be disseminated for improved construction worker safety education and training.

Thesis (M.S.)--Purdue University, 2004. / Available from National Technical Information Service, Springfield, Va., 2004. Includes bibliographical references (leaves 78-80). Also available online.

Collisions between personnel on foot and heavy equipment or materials on a construction site can be characterized as a contact collision. These types of incidents are a common occurrence on a work site. Technology is needed to improve work zone safety by alerting workers that are in danger of collisions pro-actively and in real-time. Developing this technology may assist in collecting previously un-recorded data on "near-misses" (close-calls). An approach is presented in this paper that is based on wireless radio frequency technology to alert workers in real-time when they are in danger. Various experiments are described that have been conducted in order to gain better understanding of the technology's potential, including measuring equipment blind spots and alert (or safety) zones. Blind spots areas are measured for six common construction vehicles to help determine the required (or minimum) alert distance (safety zone) for the equipment. A computer program was developed in-house to automatically calculate the percentage of blind spots on 2-dimensional planes and in the overall 3-dimensional volume. The blind spots results directly indicate the necessary safety zones for the equipment. The proximity device results show that technology demonstrated the capability of collecting important safety data while pro-actively detecting hazardous situations and warning workers and equipment operators during imminent potential hazardous events. Furthermore, the presented research can lead to improve the overall safety performance in construction and elsewhere through improved learning and education by providing relevant information to decision makers at all levels.

Although the origins of Radio Frequency Identification (RFID) technology can be traced back for many years, it is only recently that RFID has experienced rapid growth. That growth is mainly due to the increasing application of this technology in various supply chains. The widening of the implementation of RFID technology in supply chains has posed many challenges and one of the biggest is the degradation of the RFID system performance when tagging metallic objects, or when the RFID system operates in a metallic environment. This thesis focuses on tackling the issue of having metallic objects in an Ultra High Frequency (UHF) RFID system. The work presented in this thesis contributes to the research on UHF RFID systems involving metallic objects in several ways: (a) the development of novel RFID tags that range from a simple tag for general applications to tags suitable for metallic object identification; (b) the tag designs target the criteria of minimal tag size and cost to embrace the vision of item level tagging; and (c) the analysis of the performance (through theoretical predictions and practical measurements) of an RFID tag near metallic structures of various shapes and sizes. The early part of this thesis provides a brief introduction to RFID and reviews the background information related to metallic object identification for UHF RFID systems. The process of designing a basic tag, and additional information and work done related to the process, are outlined in the early part of this thesis. As part of this fundamental research process, and before proceeding to the designing of tags specifically for metallic objects, a small and low cost RFID tag for general applications was developed. Details of the design of this tag, with the application of this tag for animal identification, are presented. In the later parts of the work, different tag design approaches were explored and this has generated three rather different RFID tags suitable for attaching to metallic objects. The aim of this research is not just to design tags for metallic objects but also to tackle the constraints of having tags that are small in size, cost effective and suited in size to some familiar objects. Hence, in the later part of this research, the work took a step further where one of the three tags designed for metallic objects addressed the challenge of identifying individual small metallic beverage cans. RFID involves tagging of different types of objects and a tag may be required to be located in a depression of a metallic object. In the final part of this research, the read range performance of one of the RFID tags designed for metallic objects was analysed when the tag was located in metallic depressions of various shapes and sizes. The analysis was performed from a combination of theoretical calculation and simulation perspectives, and also through practical real-life measurements. Metallic objects are very common around us. Their presence is unavoidable and so to identify them, having the appropriate RFID tags suitable for operation on metallic surfaces is essential. Frequently the tags must be small in size and low in cost to allow identification at item level of individual small metallic objects. Understanding and being aware of the potential effects of metallic structures of various shapes and sizes on the tag performance is thus important. The research in this thesis into all the above can bring the industry further towards full deployment of RFID down to item level tagging. / Thesis (Ph.D.) - University of Adelaide, School of Electrical and Electronic Engineering, 2008

Unmanned Aerial Vehicles are often used for reconnaissance, search and rescue, damage assessment, exploration, and other tasks that are dangerous or prohibitively difficult for humans to perform. Often, these tasks include traversing indoor environments where radio links are unreliable, hindering the use of remote pilot links or ground-based control, and effectively eliminating Global Positioning System (GPS) signals as a potential localization method. As a result, any vehicle capable of indoor flight must be able to stabilize itself and perform all guidance, navigation, and control tasks without dependence on a radio link, which may be available only intermittently. Since the availability of GPS signals in unknown environments is not assured, other sensors must be used to provide position information relative to the environment. This research covers a description of different ranging sensors and methods for incorporating them into the overall guidance, navigation, and control system of a flying vehicle. Various sensors are analyzed to determine their performance characteristics and suitability for indoor navigation, including sonar, infrared range sensors, and a scanning laser rangefinder. Each type of range sensor tested has its own unique characteristics and contributes in a slightly different way to effectively eliminate the dependence on GPS. The use of low-cost range sensors on an inexpensive passively stabilized coaxial helicopter for drift-tolerant indoor navigation is demonstrated through simulation and flight test. In addition, a higher fidelity scanning laser rangefinder is simulated with an Inertial Measurement Unit (IMU) onboard a quadrotor helicopter to enable active stabilization and position control. Two different navigation algorithms that utilize a scanning laser and techniques borrowed from Simultaneous Localization and Mapping (SLAM) are evaluated for use with an IMU-stabilized flying vehicle. Simulation and experimental results are presented for each of the navigation systems.