"A well-known challenge in estimating the distance of the antenna pair in time-of-arrival (ToA) based RF localization systems is the problem of obstruction of the direct path (DP) between transmitter and receiver. The absence of DP component in received channel profile creates undetected direct path (UDP) conditions. UDP condition, in turn, will cause occurrence of unexpected large ranging errors which pose serious challenge to precise indoor localization. Analysis of the behavior of the ranging error in such conditions is essential for the design of precise ToA-based indoor localization systems. This dissertation discusses two open problems in ToA-based indoor localization systems. The first contribution of this dissertation discusses the problem of modeling of dynamic behavior of ranging error. We propose a novel analytical framework for analysis of dynamic spatial variations of ranging error observed by a mobile user based on an application of Markov chain. The model relegates the behavior of ranging error into four main categories associated with four states of Markov process. Parameters of distributions of ranging error in each Markov state are extracted from empirical data collected from a measurement-calibrated ray tracing algorithm simulating a typical office environment. The analytical derivation of parameters of the Markov model employs the existing path-loss models for first detected path and total multipath received power in the same office environment. Results of simulated errors from the Markov model and actual errors from empirical data show close agreement. The second contribution of this dissertation discusses the problem of identification of UDP condition given an unknown channel profile. Existing of UDP condition in a channel profile poses serious degradation to ranging estimate process. Therefore, identification of occurrence of UDP condition is of our subsequent concern. After identification, the second step is to mitigate ranging errors in such conditions. In this dissertation we present two methodologies, based on binary hypothesis testing and an application of artificial neural network design, to identify UDP conditions and mitigate ranging error using statistics extracted from wideband frequency-domain indoor measurements conducted in typical office building. "

As aplicações da tecnologia de identificação por radiofrequência (RFID) em hospitais movimenta uma importante área de estudo no setor de saúde. Acompanhando o crescente número de trabalhos na área, encontra-se a necessidade de sistematização e categorização destas aplicações e de estudos que apresente soluções para o processo logístico hospitalar, particularmente, sob a perspectiva do fluxo de pacientes em ambulatórios de ensino. Diante deste cenário, a presente tese propõe um modelo de referência para a identificação e análise de aplicações RFID, considerando o objeto de estudo em questão. A revisão da literatura inicia-se abordando a Logística Hospitalar, apresentando os principais autores e correntes dessa área de pesquisa, apontando para a importância do fluxo de pacientes como elemento direcionador dos demais fluxos logísticos. Em seguida, é realizado um levantamento e categorização das aplicações da RFID em organizações hospitalares, permitindo a análise e o entendimento de suas principais características. Dessa forma, três bases apoiam o método de pesquisa. O primeiro é a revisão bibliográfica. O segundo é a metodologia para o desenvolvimento de modelos de referência na área de TI e por final, a avaliação do modelo por profissionais de saúde e TI, futuros usuários do modelo. Como contribuição da pesquisa, destaca-se o desenvolvimento e prescrição de um conjunto de atividades voltadas à identificação e análise de aplicações RFID dentro da visão de Logística Hospitalar, objetivando uma maior aproximação entre profissionais de saúde e TI na etapa de planejamento do processo de implantação da tecnologia em um ambiente ambulatorial de ensino. / The applications of radio frequency identification technology (RFID) in hospitals move an important area of study in the healthcare. Accompanying the growing body of research on this topic, there is a need for systematization of such applications and proposals for solutions to the hospital logistics processes, particularly from the perspective of patient flow logistics in teaching ambulatory care setting. In this way, this thesis proposes a reference model for the identification and analysis of RFID applications, considering this object of research. The literature review begins by addressing the hospital logistics management, presenting the main authors of this emerging area of research, pointing to the importance of patient flow. Next, we conducted a review and categorization of RFID applications in hospital organizations, theme of this research, allowing the analysis and understanding of its main characteristics. Thus, three bases support the research method. The first is the literature review. The second is the methods for reference model development in IT field and the third, the evaluation by health and IT professionals, potential users of model. As a research contribution, a set of activities designed to identifying and analyzing RFID applications in hospital logistics was developed, aimed to approach health and IT professionals in the planning stage of RFID implementation process.

Mikrochip, eller integrerad krets, är en samling av elektroniska kretsar på en mindre platta. De går att finna i nästan alla elektroniska produkter, såsom i mobiler eller självkörande bilar. Idag har denna teknik blivit så liten att människor kan implantera den i kroppen, där användningsområdena är många och fortfarande relativt outforskade. Ny teknik kommer ofta med positiva och negativa aspekter, en teknik som kan integreras med kroppen kan för individen kännas integritetskränkande, främmande eller obehagligt. Detta är en kvalitativ studie där vi genom intervjuer har undersökt vilka attityder ungdomar i Sverige har till implantat av mikrochip. Studien har identifierat vad ungdomar har för attityder och åsikter kring mikrochip i kontexten av deras egna privatliv, hälsa, vardagsliv och datasäkerhet.

Professors who manage large classes are unrealistically expected to grade each student fairly and accurately. Even with all of the technological advancements that have occurred in the past thirty years, very little progress has been made in classroom management, and as a result, professors are not equipped with enough tools to successfully manage large class sizes. Because radio frequency identification (RFID) technology is making its way into student issued identification cards, there is an opportunity to use it as a tool to aid professors in the classroom. The focus of this paper is to discover the most effective system that can be implemented as a classroom management instrument. Through multi criteria analysis, several different infrastructures are examined and compared to determine the best alternative. The result of an effective system leads to a reduction in time spent taking attendance, an increase in student performance, an increase in the fairness and accuracy of recording classroom participation, and an enhanced professor-student relationship.

The Brigham Young University (BYU) Radio Astronomy Systems group, in collaboration with the National Radio Astronomy Observatory (NRAO), the Center for Astrophysics at West Virginia University (WVU), and the Green Bank Observatory (GBO) have developed, and commissioned, a broadband real-time digital back end processing system for a 38-element phased array feed (PAF) with 150 MHz of instantaneous bandwidth. This system is capable of producing coarse and fine channel correlations, and implements a real-time beamformer that forms 7 simultaneous dual-polarized beams. This thesis outlines the hardware and software development for the digital back end and presents on-telescope commissioning results. This system has been measured to provide an unprecedented low Tsys/η noise level of 28 K and can perform maps of galactic hydrogen observations in a fraction of the time of a conventional single horn feed. The National Radio Astronomy Observatory (NRAO) has recently announced the concept and development of the next generation Very Large Array (ngVLA), a large interferometric array consisting of 300 radio telescopes and longest baseline (distance between a pair of antennas) of 300 km. Large interferometric arrays have been shown to attenuate radio frequency interference (RFI) because it is decorrelated as it propagates across long baselines. This is not always sufficient, especially with dense core array geometries and with the ever-increasing amount of strong RFI sources. Conventional RFI projection-based mitigation techniques have performed poorly on large interferometers because of covariance matrix estimation error due to decorrelation when identifying interference subspace parameters. This thesis presents an algorithm that overcomes the challenge of decorrelation by applying subspace projection via subarray processing (SP-SAP). Each subarray is designed to have a set of elements with high mutual correlation in the interferer for better estimation of subspace parameters. In simulation, compared to the former approach of applying subspace projection on the full array, SP-SAP improves mitigation of the RFI on the order of 9 dB. A signal of interest is shown then to be observable through the RFI in a full synthetic image.

The aim of this thesis is to investigate the properties of a Radio Frequency capacitive discharge at atmospheric pressure in argon. In these conditions where the pressure x distance product is around 150 Torr.cm, the discharge usually consists of several locally hot filaments. By pulsing the RF generator with an appropriate width and period, it was found possible to control the filament to glow transition in order to obtain a diffused and stable plasma.¶ The 2 mm gap between the electrodes is open to the ambient air and fed with argon via one hundred submillimetric holes regularly spread on the surface of the top electrode. This configuration allows “on-line” surface treatment of polymer films without having to turn the discharge off between successive samples. An important and lasting improvement of the polymer wettability is quickly obtained without risk of damage. The plasma diagnostic methods are emission spectroscopy and electric measurements. The Stark broadening of the Balmer β transition line of atomic hydrogen is measured to determine a plasma density of 10^15/cm3 in the filamentary mode. The glow mode density estimation was based on power balance yielding a density of 5×10^11/cm3. Emission line ratios between neutrals and Ar+ ions are used in the Saha equation to calculate the electron temperature. It results in an approximation of 1.3 eV for the glow mode and 1.7 eV for the filaments.¶ A unidimensional self-consistent fluid model is developed to gain insight into the homogeneous discharge behaviour. Poisson’s equation for the electric field is coupled to the first moments of the Boltzmann equation (continuity equation, drift-diffusion equation and energy equation). Transport and reaction coefficients are obtained from the mean energy of the electrons.¶ The model is applied to a reduced argon kinetic with the main ionization and excitation processes. Simulation results are in agreement with experimental measurements. The atmospheric pressure RF discharge is similar to a lower pressure RF discharge for which the ionization occurs mainly inside the oscillating sheaths where electrons are the most energetic

<p>The purpose of this master thesis has been to develop a baggage handling process at Stockholm Skavsta Airport that is cost-efficient, in order to prepare for the expected expansion of the airport. When developing the new process it was a directive to examine the possibilities of using radio frequency identification, RFID, technology and also that the required investment for the new process should have a payback time of no more than two to three years. The current process contains a completely manual sorting activity, which is both costly in terms of personnel and creates some mishandling of baggage due to the human factor. Our recommendation is a baggage handling process that use automatic sorting through RFID technology that eliminates the mishandling of baggage and reduce the personnel costs and at the same time have a payback period of less than three years. The main cost driver is the RFID tag costs and therefore our process is a so called closed-loop system, where the tags are reused several times and require very little work in between uses. The proposed physical layout consists of a drawing of the physical layout of the baggage sorting hall, a description of the RFID system, and the required information system software.</p>

Algorithms and simulators comprised of SPICE3 as a circuit level simulator and two device simulators EOFLOW and PROPHET for accurate simulation of new types of devices are presented in this thesis. An integration of EOFLOW with SPICE3 creates a capability for efficient simulation of a system containing interconnected electroosmotic flow channels together with control electronics. Using this simulator, an accurate simulation of a complex interconnection of channels has been performed. In addition, various flow control schemes have been evaluated for their effectiveness. Coupling of PROPHET and SPTCE3 allows for the simulation of accurate semiconductor device models. This capability is necessary for critical RF and analog applications. The coupled SPICE3-HB-PROPHET simulator incorporates the harmonic balance algorithm for large-signal frequency domain analysis. Applications of this analysis are demonstrated in the noise coupling between devices sharing the same silicon substrate. / Graduation date: 2003

Inductors are extensively used in the design of radio-frequency circuits. In the last decade, the integration of passive components, especially inductors on silicon chips, has led to the widespread development and implementation of Radio Frequency Integrated Circuits (RFICs) in CMOS technologies. However, on-chip passive inductors occupy a large silicon chip area and hardly scale down with technology scaling. Therefore, on-chip passive inductors become formidable obstacles to the realization of highly dense RFICs to be integrated with other highly dense digital circuits on a single chip using a common fabrication process. In recent years, researchers have focused on replacing passive inductors with transistor-only active circuits, namely active inductors. Active inductors can be realized with only a few transistors, which scale down with technology scaling. Therefore, they occupy a fraction of the chip area of their passive counterparts, and can be implemented densely in CMOS processes. Unlike passive inductors, bias dependent operations of active inductors allow for the tuning of their inductance and quality factor Q, and in turn, tuning the performance parameters of RFICs. This thesis focuses on the design and development of passive inductorless CMOS RFICs for ultra-wideband (UWB) receiver front-ends using active inductors. A new Q-enhanced and a new bandwidth-extended tunable active inductors are designed. Using the Q-enhanced active inductor, two tunable UWB low-noise amplifiers (LNAs) (two-stage and three-stage UWB LNAs), a UWB mixer and a wideband local-oscillator (LO) driver are designed. Active inductors are utilized to develop a novel wideband active shunt-peaking technique that decreases high-frequency losses to yield a flat gain over a wide bandwidth. A tunable multiband-UWB front-end integrating a two-stage UWB LNA, and a pair of UWB mixers driven by a pair of wideband LO drivers, is fabricated in a 90nm digital CMOS process. The passive inductorless two-stage UWB LNA, three-stage UWB LNA and UWB front-end occupy chip areas of only 0.0114mm2, 0.0227mm2, and 0.1485mm2, respectively. The active CMOS UWB front-end exhibits a measured flat gain of 22.5dB over 2.5-8.8 GHz bandwidth, and its tunability allows for varying the gain and bandwidth. / Integrated Circuits and Systems

Radiofrequency ablation (RFA) is a minimally invasive treatment for either hepatocellular carcinoma or metastasis liver carcinoma. In order to resect large lesions, the surgeon has to perform multiple time-consuming destruction cycles and reposition the RFA needle for each of them. The critical step in handling a successful ablation and preventing local recurrence is the correct positioning of the needle. For small tumors, the surgeon places the middle of the active needle tip in the center of the tumor under intra-operative ultrasound guidance. When one application is not enough to cover the entire tumor, the surgeon needs to repeat the treatment after repositioning of the needle, but US guidance is obstructed by the opacity stemming from the first RFA application. In this case the surgeon can only rely on anatomical knowledge and the repositioning of the RFA needle becomes a subjective task limiting the treatment accuracy. We have developed a computer assisted surgery guidance application for this repositioning procedure. Our software application handles the complete process from preoperative image analysis to tool tracking in the operating room. Our framework is mostly used for this RFA procedure, but is also suitable for any other medical or surgery application.