The design and development of a software defined radio (SDR) receiver prototype has been completed. The goal is to replace the existing automatic identification system (AIS) manufactured by Vesper Marine with a software driven system that reduces costs and provides a high degree of reconfigurability. One of the key concepts of the SDR is the consideration of directly digitizing the radio frequency (RF) signal using subsampling. This idea arises from the ambition to implement an analog-to-digital converter (ADC) as close to the antenna interface as practically possible. Thus, majority of the RF processing is encapsulated within in the digital domain. Evaluation of a frequency planning strategy that utilizes a combination of subsampling and oversampling will illustrate how the maritime bandwidth is aliased to a lower frequency. An analog front-end (AFE) board was constructed to implement the frequency planning strategy so that the digitized bandwidth can be streamed into a field programmable gate array (FPGA) for real-time processing. Research is shown on digital front-end (DFE) techniques that condition the digitized maritime signal for baseband processing. The process of a digital down converter (DDC) is conducted by an FPGA, which acquired the in-phase and quadrature signals. By implementing a digital signal processor (DSP) for baseband processing, demodulation on an AIS test signal is evaluated. The SDR prototype achieved a receiver sensitivity of -113dBm, outperforming the required sensitivity of -107dBm specified in the International Electrotechnical Commission (IEC) 62287-1 standard for AIS applications [1].

Submitted by Richard Fonseca Francisco (richardfon1@hotmail.com) on 2018-04-23T23:20:19Z No. of bitstreams: 1 francisco_rf_dr_rcla.pdf: 14432661 bytes, checksum: 7ac5b095d6b752095576e261247da48b (MD5) / Rejected by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br), reason: - Falta a capa on 2018-04-24T13:20:15Z (GMT) / Submitted by Richard Fonseca Francisco (richardfon1@hotmail.com) on 2018-04-24T14:01:59Z No. of bitstreams: 1 francisco_rf_dr_rcla.pdf: 14729213 bytes, checksum: f0a8f340fdf4b7d8fd75e6b825af99e4 (MD5) / Approved for entry into archive by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br) on 2018-04-24T17:19:56Z (GMT) No. of bitstreams: 1 francisco_rf_dr_rcla.pdf: 14719670 bytes, checksum: ef86656d898eb92e8d48fd2cc0fdef35 (MD5) / Made available in DSpace on 2018-04-24T17:19:56Z (GMT). No. of bitstreams: 1 francisco_rf_dr_rcla.pdf: 14719670 bytes, checksum: ef86656d898eb92e8d48fd2cc0fdef35 (MD5) Previous issue date: 2018-04-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Diante da importância das águas subterrâneas para os diversos usos, particularmente o abastecimento público, e considerando os crescentes impactos nas reservas subterrâneas decorrentes de superexplotação, bem como a degradação da qualidade da água por atividades antrópicas, torna-se imprescindível o estabelecimento de instrumentos de planejamento, gestão do uso e proteção dos recursos hídricos subterrâneos. Por esta razão, o objetivo principal desta pesquisa foi apresentar uma proposta metodológica para avaliar a vulnerabilidade natural e perigo de contaminação de aquíferos livres granulares, a partir de uma abordagem centrada na integração entre o parâmetro de Dar Zarrouk denominado condutância longitudinal unitária e demais fatores que interferem na estimativa destes processos. Para tanto, os métodos SDR e SDR-PERIGO foram desenvolvidos e aplicados experimentalmente no Aquífero Rio Claro, no município de Rio Claro/SP, a fim de estimar a vulnerabilidade natural e perigo de contaminação, respectivamente. A espessura e a resistividade elétrica da zona não saturada, utilizadas para o cálculo da condutância longitudinal unitária, foram obtidas através do processamento e análise de sondagens elétricas verticais. Os demais fatores empregados foram a declividade, taxa anual de recarga do aquífero e uso e cobertura do solo. Os pesos de influência dos fatores foram determinados com o auxílio da Análise Hierárquica de Processos, a fim de reduzir a subjetividade e eventuais erros inerentes à tomada de decisão. Em seguida, os mapas de fator foram integrados em ambiente SIG, com base na Análise Multicritério, por meio da aplicação do método da Combinação Linear Ponderada. No que se refere ao método SDR, toda a área de estudo apresentou vulnerabilidade natural alta, resultado compatível com aqueles reportados em trabalhos anteriores e conforme o esperado, considerando as características dos sedimentos areno- argilosos da Formação Rio Claro. Com relação ao método SDR-PERIGO, o perigo é alto em aproximadamente 72% da área de estudo, devido à associação entre a alta vulnerabilidade natural e atividades potencialmente poluidoras. De modo geral, locais com alto perigo de contaminação foram relacionados, principalmente, à área urbano- industrial e aos cultivos de cana-de-açúcar e de cítricos. Áreas com perigo de contaminação baixo ou nulo foram encontradas onde ocorrem tipos de uso e cobertura da terra com potencial de contaminação insignificante, como vegetação natural e áreas úmidas. No que se refere aos métodos SDR e SDR-PERIGO, a análise integrada da condutância longitudinal unitária e demais parâmetros forneceu resultados robustos, sendo vantajosos sob o ponto de vista da praticidade na utilização e do número reduzido de parâmetros requeridos. Assim, estes métodos poderão ser empregados como alternativas àqueles considerados tradicionais e já consagrados na literatura pertinente, podendo constituir, futuramente, importantes ferramentas para a proteção de aquíferos livres granulares. / Considering the importance of groundwater for several uses, particularly the public supply, and considering the increasing impacts on groundwater reserves due to overexploitation, as well as the degradation of water quality by anthropogenic activities, it becomes essential to establish tools for planning, management of the use and protection of groundwater resources. For this reason, the aim of this research was to present a methodological proposal to assess the natural vulnerability and hazard to contamination of the granular unconfined aquifers, by means of an approach focused on the integration between the Dar Zarrouk parameter denominated Longitudinal Unit Conductance and other factors that interfere in the estimation of these processes. In order to evaluate the natural vulnerability and hazard to contamination, the SDR and SDR-HAZARD methods were developed and experimentally applied in the Rio Claro Aquifer, in the Rio Claro municipality, São Paulo State, Brazil. The longitudinal unit conductance results from the ratio between the thickness of the unsaturated zone and its electrical resistivity, which were obtained by processing and analysis of vertical electrical soundings. Other factors were used, such as slope, annual rate of aquifer recharge and land use. Factor weights were determined with the aid of the Analytic Hierarchy Process, in order to reduce the subjectivity and eventual inconsistencies in the decision-making process. Posteriorly, the factor maps were integrated into GIS based on Multicriteria Analysis, through the application of the Weighted Linear Combination method. Regarding the SDR method, the entire study area presented high natural vulnerability, a result compatible with those reported in previous studies and as expected, considering the characteristics of sandy-clay sediments of the Rio Claro Formation. With respect to the SDR-HAZARD method, the hazard is high in approximately 72% of the study area, due to the association between high natural vulnerability and potentially polluting activities. Generally, places with high contamination hazard were mainly related to industrial and urban areas, including sugarcane and citrus crops. Areas with low or null contamination hazard were found where there are types of land use with negligible potential contamination, such as natural vegetation and wetlands. As regards the SDR and SDR-HAZARD methods, the integrated analysis of the longitudinal unit conductance and other parameters provided robust results, whose advantages are the practicality use and reduced number of required parameters. Thus, these methods may be employed as alternatives to those considered traditional and already established in the related literature, providing, in the future, important tools for the protection of granular unconfined aquifers.

Abstract Mammalian peroxisomes contain two parallel multifunctional enzymes (MFE), MFE type 1 and MFE type 2 (MFE-2), which are responsible for the degradation of fatty acids. They both catalyze the second and third reactions of the β-oxidation pathway, but through reciprocal stereochemical courses. MFE-2 possesses (2E)-enoyl-CoA hydratase-2 and (3R)-hydroxyacyl-CoA dehydrogenase activities. In addition, the carboxy-terminal part is similar to the sterol carrier protein type 2 (SCP-2). The purpose of this work was to study the structure-function relationship of functional domains of mammalian MFE-2 by recombinant DNA technology, enzyme kinetics and X-ray crystallography. The work started with the identification of conserved regions in MFE-2. This information was utilized when dehydrogenase, hydratase-2 and/or SCP-2-like domain were produced as separate recombinant proteins. Subsequently, both dehydrogenase and SCP-2-like domains were crystallized and their crystal structures were solved. The structure of the dehydrogenase region of rat MFE-2 contains the basic α/β short-chain alcohol dehydrogenase/reductase (SDR) fold and the four-helix bundle at the dimer interface, which is typical of dimeric SDR enzymes. However, the structure has a novel carboxy-terminal domain not seen among the known structures. This domain lines the active site cavity of the neighbouring monomer, reflecting cooperative behaviour within a homodimer. The monomeric SCP-2-like domain of human MFE-2 has the same fold as rabbit SCP-2. The structure includes a hydrophobic tunnel occupied by an ordered Triton X-100 molecule, demonstrating the ligand-binding site. Compared to the unliganded rabbit SCP-2 structure, the position of the carboxy-terminal helix is different. The movement of this helix in the liganded human SCP-2-like domain resulted in the exposure of a peroxisomal targeting signal, suggesting ligand-assisted protein import into peroxisomes. The roles of conserved protic residues in the hydratase-2 region of human MFE-2 were studied by mutating them to alanine. In the first step, the ability of mutated variants to utilize oleic acid in vivo was tested with Saccharomyces cerevisiae fox-2 cells (devoid of endogenous MFE-2). Subsequently, in vitro characterization of the mutant enzymes revealed two amino acid residues, Glu366 and Asp510, vital for hydratase-2 activity. The results indicate that the acid-base catalysis is valid for hydratase-2.

abstract: In this paper, the Software Defined Radio (SDR) platform is considered for building a pseudo-monostatic, 100MHz Pulse-Doppler radar. The SDR platform has many benefits for experimental communications systems as it offers relatively cheap, parametrically dynamic, off-the-shelf access to the Radiofrequency (RF) spectrum. For this application, the Universal Software Radio Peripheral (USRP) X310 hardware package is utilized with GNURadio for interfacing to the device and Matlab for signal post- processing. Pulse doppler radar processing is used to ascertain the range and velocity of a target considered in simulation and in real, over-the-air (OTA) experiments. The USRP platform offers a scalable and dynamic hardware package that can, with relatively low overhead, be incorporated into other experimental systems. This radar system will be considered for implementation into existing over-the-air Joint Radar- Communications (JRC) spectrum sharing experiments. The JRC system considers a co-designed architecture in which a communications user and a radar user share the same spectral allocation. Where the two systems would traditionally consider one another a source of interference, the receiver is able to decode communications information and discern target information via pulse-doppler radar simultaneously. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2019

In this thesis, several computationally-efficient approximate soft demodulation schemes are developed for multiple-input multiple-output (MIMO) communication systems. These soft demodulators are designed to be deployed in the conventional iterative receiver ('turbo') architecture, and they are designed to provide good performance at substantially lower computational cost than that of the exact soft demodulator. The proposed demodulators are based on the principle of list demodulation and can be classified into two classes, according to the nature of the list-generation algorithm. One class is based on a tree-search algorithm and the other is based on insight generated from the analysis of semidefinite relaxation techniques for hard demodulation. The proposed tree-search demodulators are based on a multi-stack algorithm, developed herein, for efficiently traversing the tree structure that is inherent in the MIMO demodulation problem. The proposed scheme was inspired, in part, by the stack algorithm, which stores all the visited nodes in the tree in a single stack and chooses the next node to expand based on a 'best-first' selection scheme. The proposed algorithm partitions this global stack into a stack for each level of the tree. It examines the tree in the natural ordering of the levels and performs a best-first search in each of the stacks. By assigning appropriate priorities to the level at which the search for the next leaf node re-starts, the proposed demodulators can achieve performance-complexity trade-offs that dominate several existing soft demodulators, including those based on the stack algorithm and those based on 'sphere decoding' principles, especially in the low-complexity region. In the second part of this thesis it is shown that the randomization procedure that is inherent in the semidefinite relaxation (SDR) technique for hard demodulation can be exploited to generate the list members required for list-based soft demodulation. The direct application of this observation yields list-based soft demodulators that only require the solution of one SDP per demodulation-decoding iteration. By approximating the randomization procedure by a set of independent Bernoulli trials, this requirement can be reduced to just one semidefinite program (SDP) per channel use. An advantage of these demodulators over those based on optimal tree-search algorithms is that the computational cost of solving the SDP is a low-order polynomial in the problem size. The analysis and simulation experiments provided in the thesis show that the proposed SDR-based demodulators offer an attractive trade-off between performance and computational cost. The structure of the SDP in the proposed SDR-based demodulators depends on the signaling scheme, and the initial development focuses on the case of QPSK signaling. In the last chapter of this thesis, the extension to MIMO 16-QAM systems is developed, and some interesting observations regarding some existing SDR-based hard demodulation schemes for MIMO 16-QAM systems are derived. The simulation results reveal that the excellent performance-complexity trade-off of the proposed SDR-based schemes is preserved under the extension to 16-QAM signaling. / Thesis / Doctor of Philosophy (PhD)

Traffic Collision Avoidance Systems (TCAS) are safety-critical systems that are deployed on most commercial aircraft in service today. However, TCAS transactions were not designed to account for malicious actors. While in the past it may have been infeasible for an attacker to craft arbitrary radio signals, attackers today have access to open-source digital signal processing software like GNU Radio and inexpensive Software Define Radios (SDR). Therefore, this thesis presents motivation through analytical and experimental means for more investigation into TCAS from a security perspective. Methods for analyzing TCAS both qualitatively and quantitatively from an adversarial perspective are presented, and an experimental attack is developed in GNU Radio to perform an attack in a well-defined threat model. / Master of Science / Since 1993, the Federal Aviation Administration (FAA) requires that many commercial turbine-powered aircraft to be outfitted with an on-board mid-air collision mitigation system. This system is known as the Traffic Collision Avoidance System (TCAS) in the United States, and it is known as the Airborne Collision Avoidance System (ACAS) in other parts of the world. TCAS/ACAS is a type of safety-critical system, which means that implementations need to be highly tolerant to system failures because their operation directly affects the safety of the on-board passengers and crew. However, while safety-critical systems are tolerant to failures, the designers of these systems only account for failures that occur in a cooperative environment; these engineers fail to account for “bad actors” who want to attack the weaknesses of these systems, or they assume that attacking such a system is infeasible. Therefore, to demonstrate how safety-critical systems like TCAS/ACAS are vulnerable to such bad actors, this thesis presents a method for manipulating the TCAS/ACAS in the favor of a bad actor. To start, a method for qualitatively and quantitatively analyzing the system’s vulnerabilities is presented. Then, using Software Defined Radio (SDR), which is a free and open-source effort to combine the flexibility of software with the power of wireless communication, this thesis shows how an actor can craft wireless signals such that they appear to look like an aircraft on a collision course with a target.

In this thesis, we benchmark the Cognitive Radios Test System version 2.0 (CRTSv.2) to analyze its software performance with respect to its internal structure and design choices. With the help of system monitoring and profiling tools, CRTSv.2 is tested to quantitatively evaluate its features and understand its shortcomings. With the help of GNU Radio, a popular, easy-to-use software radios framework, we ascertain that CRTSv.2 has a low memory footprint, fewer dependencies and overall, is a lightweight framework that can potentially be used for real-time signal processing. Several open-source measurement tools such as valgrind, perf, top, etc. are used to evaluate the CPU utilization, memory footprint and to postulate the origins of latencies. Based on our evaluation, we observe that CRTSv.2 shows a CPU utilization of approximately 9% whereas GNU Radio is 59%. CRTSv.2 has lower heap memory consumption of approximately 3MB to GNU Radio's 25MB. This study establishes a methodology to evaluate the performance of two SDR frameworks systematically and quantitatively. / Master of Science / When picking the best person for the job, we rely on the person's performance in past projects of a similar nature. The same can be said for software. Software radios provide the capability to perform signal processing functions in software, making them prime candidates towards solving modern problems such as spectrum scarcity, internet-of-things(IoT) adoption, vehicle-to-vehicle communication etc. In order to operate and configure software radios, software frameworks are provided that let the user make changes to the waveform, perform signal processing and data management. In this thesis, we consider two such frameworks,GNU Radio and CRTSv.2. A software performance evaluation is conducted to assess framework overheads contributing to operation of an orthogonal frequency-division multiplexing (OFDM) digital modulation scheme. This provides a quantitative analysis of a signals-specific use case which can be used by researchers to evaluate the optimal framework for research. This analysis can be generalized for different signal processing capabilities by understanding the total framework overhead removed from signal processing costs.

ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / A traditional Receiver, Modulator, Bit Synchronizer, Frame Synchronizer and Front-End Processor (FEP) with local RAID storage from numerous satellite ground station equipment providers is typically used to satisfy current needs in mission ground stations. The development of Software Defined Radios (SDRs) with reprogrammable personalities has led to the consolidation of these processing elements, and will become the standard for years to follow. CVG-Avtec Systems, Inc. has been a pioneer in the SDR industry, integrating several ground station functions into a one system solution. Its High Data Rate Modem (HDRM) architecture replaces racks of previous generation equipment, providing greater functionality in a smaller footprint. The Field Programmable Gate Array (FPGA) based HDRM is a one system solution that inputs Intermediate Frequency (IF) data and outputs packetized data over IP for data distribution. These new architectures are capitalizing on the revolution in electronics and networking technologies. This paper will discuss the architecture of the HDRM and how it optimizes ground station data processing in a high-rate environment.

This report presents an implementation of the software part in a software definedradio. The radio is not entirely implemented in software and therefore there arecertain limitations on the received signal. The parts implemented are oscillator,decimation filter, carrier synchronization, time synchronization, package detection,and demodulation. Different algorithms were tested for the different partsto measure the power consumption. To understand how the number of bits usedto represent the signal affects the power consumption, the number of bits wasreduced from 20 bits to 10 bits. This reduction reduced the power consumptionfrom 2.57mW to 1.89mW. A small change in the choice of algorithms was thenmade which reduced the power consumption to 1.86mW. Then the clock rate wasreduced for some parts of the system which reduced the power consumption to1.05mW.

<p>CMMB (China Multimedia Mobile Broadingcasting) is a wireless broadcastingchannel standard for low bandwidth, low cost hand-held digital TV is adopted byall continental Chinese government TV broadcasting companies and some HongKong private TV broadcasting companies. The business potential is high, yet thefuture is hard to predict because it might be replaced by GB200600 or DTMB. Thedigital modulation is based on OFDM with pilot supporting channel estimationand equalization and CP supporting multi-path induced ISI problems.This thesis investigates the implement a CMMB system using a SDR platform.Simulation chain was implemented using MATLAB with full data precision includingCMMB transmitter and receiver. The transmitter behavior model includes RSencoder, LDPC encoder, OFDM modulation, etc. The receiver behavior modelincludes OFDM demodulation, channel estimation, channel equalization, LDPCdecoder, RS decoder, etc. Different channel models emulating pathloss, whitenoise, multi-path, and glitch were modeled. Based on the simulation chain andchannel models, T-domain, F-domain channel estimator and equalizer were implemented,optimized. Optimized TD-FD models for different mobility scenarioswere proposed. The focus of the thesis is on 2D (FD-TD) channel estimation andequalization.</p>