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Full-Text Articles in Engineering
Pdms Microchannel Scaffolds For The Isolation Of Individual Axon Regeneration, Bong Kyun Kim
Pdms Microchannel Scaffolds For The Isolation Of Individual Axon Regeneration, Bong Kyun Kim
Theses and Dissertations - UTB/UTPA
Injuries to the peripheral nervous system often result in the loss of sensory or motor function within the effected nerve. Nerve scaffolds provide the mechanical support and topographical cues to axon regeneration such that the gap within the injured nerve is bridged and functional recovery is restored. The Microchannel Peripheral Nerve Scaffold, µPNS, was fabricated from PDMS using micromachining techniques that allow for the unprecedented control of microchannel dimensions and paths and therefore, the production of highly customizable Nerve scaffolds for peripheral nerve regeneration applications. The device was then implanted within the sciatic nerves of a series of Lewis rats, …
Security Integrity Of Ekg Signal Monitoring Under Different Network Attack Conditions, Raghava Teja Pingali
Security Integrity Of Ekg Signal Monitoring Under Different Network Attack Conditions, Raghava Teja Pingali
Theses and Dissertations - UTB/UTPA
This thesis focuses on issues related with monitoring of EKG signals under different network attack traffic conditions. It is becoming common for modern hospitals to monitor real time EKG signals of patients on computers that are usually connected to networks. If the network suffers with attack conditions, it can affect connected computers and alter EKG signals monitoring, hence raising false alarms. Denial of Service attacks may silently affect the real time monitoring of EKG signals. Altering of EKG signals may result in loss of integrity and it can violate CIA triad of security. In this thesis, different attack conditions were …
Improving Queueing Implementation On High Speed Switches, Wendy Hernandez
Improving Queueing Implementation On High Speed Switches, Wendy Hernandez
Theses and Dissertations - UTB/UTPA
In this thesis two different conventional shared memory allocation schemes - Dynamic Threshold (DT) and Threshold-based Filtering (TF) - are evaluated under varied traffic conditions in order to determine the optimal configuration for each tested scenario. The effect that a changing ABL, load, and ratio between buffer size and ports have on the packet loss is observed for buffer sharing schemes DT and TF schemes. This allowed to easily determining the Alpha and Thresholds required by DT and TF schemes respectively to obtain an optimal configuration under each of the different tested scenarios. A new shared memory allocation scheme referred …
Distributed Coordinate Tracking Control Of Multiple Wheeled Mobile Robots, Yifan Xing
Distributed Coordinate Tracking Control Of Multiple Wheeled Mobile Robots, Yifan Xing
Theses and Dissertations - UTB/UTPA
In this thesis, distributed coordinate tracking control of multiple wheeled-mobile robots is studied. Control algorithms are proposed for both kinematic and dynamic models. All vehicle agents share the same mechanical structure. The communication topology is leader-follower topology and the reference signal is generated by the virtual leader. We will introduce two common kinematic models of WMR and control algorithms are proposed for both kinematic models with the aid of graph theory. Since it is more realistic that the control inputs are torques so dynamic extension is studied following by the kinematics. Torque controllers are designed with the aid of backstepping …
Electrocardiogram Data Collection Under Network Attacks On The Mac Platform, Golshan Famitafreshi
Electrocardiogram Data Collection Under Network Attacks On The Mac Platform, Golshan Famitafreshi
Theses and Dissertations - UTB/UTPA
Increasing heart disease among human beings needs more precise treatment, which requires monitoring of electrocardiogram (ECG). In many cases, real time monitoring of ECG is needed via wireless or wireline networks. Use of network-connected computers for monitoring proposes can raise security issues, which can be created by viruses, worms, or external agents such as DoS attack traffic. Any alteration of this biomedical signal can lead to wrong diagnosis and wrong treatment. Furthermore, in healthcare industry, HIPAA rules require health information to be kept secure by providing confidentiality, integrity, and availability. This thesis investigates how integrity and availability of remotely monitored …
Evaluation Of Security Vulnerabilities Of Popular Computer And Server Operating Systems Under Cyber Attacks, Rodolfo Baez Jr.
Evaluation Of Security Vulnerabilities Of Popular Computer And Server Operating Systems Under Cyber Attacks, Rodolfo Baez Jr.
Theses and Dissertations - UTB/UTPA
Nowadays many operating systems are including security features in order to prevent network attacks, and since one of the roles of the OS is to manage the resources as efficient as possible. It is imperative to investigate the protection that is provided. Therefore, the scientific significance of this thesis was to evaluate, what type of built-in defense mechanisms that different OS’s had in place in order to mitigate these network attacks. In this thesis, we considered the security of the following globally deployed computer OS’s: Microsoft’s Windows 7, Apple’s OS X Lion, and Ubuntu 13.10. Furthermore, we also tested four …
Characterization Of Gan Thin Films Grown By Rf Magnetron Sputtering For Fabrication Of An Algan/Gan Hemt Biosensor, Rocio Yolanda Garza
Characterization Of Gan Thin Films Grown By Rf Magnetron Sputtering For Fabrication Of An Algan/Gan Hemt Biosensor, Rocio Yolanda Garza
Theses and Dissertations - UTB/UTPA
Radio-Frequency (RF) Magnetron Sputtering has been used to grow GaN thin films for future fabrication of an AlGaN/GaN HEMT biosensor. A GaN target was sputtered at various parameters on silicon and sapphire substrates, at room temperature and at elevated temperature using substrate heating and post deposition annealing treatment. The research conducted investigates the effects of sputtering gas (Argon or Nitrogen gas), RF power (40W or 50W), and pressure (4mT – 30mT) on the structural properties of the thin films. Imaging tools such as the Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), X-ray Diffractometer (XRD), and …
Seeds Of Solutions™: An Economical & Efficient Approach Towards Power Engineering Education, Eli Alvarez
Seeds Of Solutions™: An Economical & Efficient Approach Towards Power Engineering Education, Eli Alvarez
Theses and Dissertations - UTB/UTPA
Power demands are set to increase over the next twenty years; however, research shows that there may be a shortage of power engineers due to an appreciable percentage of the current power engineer workforce retiring, insufficient enrollment in power engineering programs and a lack of emphasis in power engineering at the university level. This thesis provides supporting research for future power demands, workforce and faculty shortages. Using temporary research in modern learning / teaching styles, student / teacher perceptions, educational trends and regional course offerings, this thesis describes a learning approach towards power engineering education. Designed specifically for universities with …
A 129nw Neural Amplifier And Gm-C Filter For Eeg Using Gm/Id Methodology, Samuel A. Gallegos
A 129nw Neural Amplifier And Gm-C Filter For Eeg Using Gm/Id Methodology, Samuel A. Gallegos
Theses and Dissertations - UTB/UTPA
This Thesis presents a low-power analog front-end amplifier and Gm-C filter for biomedical sensing applications, specifically for Electroencephalogram (EEG) use. The proposed neural amplifier uses a supply voltage of 1.8V, it has a mid-band gain of 40.75dB, and consumes a total current of 71.82nA, for a total dissipated power of 129.276nW. Also presented is the design of a 3rd order Butterworth Low Pass Gm-C Filter which makes use of 14.7nS transconductors; the proposed filter has a pass band suitable for EEG recording use (1-100Hz). The amplifier and filter utilize current sources without bias resistances which provide 56nA and (1.154nA x …
Applications Of Magnetostrictive Materials In The Real-Time Monitoring Of Vehicle Suspension Components, Raul Estrada
Applications Of Magnetostrictive Materials In The Real-Time Monitoring Of Vehicle Suspension Components, Raul Estrada
Theses and Dissertations - UTB/UTPA
The purpose of this project is to explore applications of magnetostrictive materials for real-time monitoring of railroad suspension components, in particular bearings. Monitoring of such components typically requires the tracking of temperature vibration and load. In addition, real-time, long-term monitoring can be greatly facilitated through the use of wireless, self-powered sensors. Magnetostrictive materials, such as Terfenol-D, have the potential to address both requirements. Currently, piezoelectrics are used for many load and energy harvesting applications; however, they are fragile and are difficult to use for static load measurements. Magnetostrictive metals are tougher, and their property of variable permeability when stressed can …
Cluster Computer Simulation Of Buffer Sharing Schemes Under Bursty Traffic Load, Javier Castillo
Cluster Computer Simulation Of Buffer Sharing Schemes Under Bursty Traffic Load, Javier Castillo
Theses and Dissertations - UTB/UTPA
In this thesis it is first analyzed the effect that different Average Burst Length, buffer size or number of ports have on the performance in terms of packet loss ratio on shared memory network switches using Complete Sharing as baseline for the memory allocation scheme. Three different shared memory allocation schemes - Sharing with a Minimum Allocation (SMA), Sharing with Maximum Queue lengths (SMXQ), and Dynamic Threshold (DT) - are then analyzed under varied traffic conditions in order to determine the best configuration for each tested scenario. Having determined the best configuration for each individual scheme under all the tested …
Distributed Formation Tracking Control Of Multiple Car-Like Robots, Chunyu Chen
Distributed Formation Tracking Control Of Multiple Car-Like Robots, Chunyu Chen
Theses and Dissertations - UTB/UTPA
In this thesis, distributed formation tracking control of multiple car-like robots is studied. Each vehicle can communicate and send or receive states information to or from a portion of other vehicles. The communication topology is characterized by a graph. Each vehicle is considered as a vertex in the graph and each communication link is considered as an edge in the graph. The unicycles are modeled firstly by both kinematic systems. Distributed controllers for vehicle kinematics are designed with the aid of graph theory. Two control algorithms are designed based on the chained-form system and its transformation respectively. Both algorithms achieve …
An Analytical And Experimental Biosensor For Human Mig Using Algan/Gan Based Hemt Devices, Hector Trevino Ii
An Analytical And Experimental Biosensor For Human Mig Using Algan/Gan Based Hemt Devices, Hector Trevino Ii
Theses and Dissertations - UTB/UTPA
An amperometric biosensor using AlGaN/GaN based HEMT devices is constructed experimentally and validated through analytical and numerical techniques for detection of a key protein in allograft rejection (Human MIG/CXCL9). The prototype developed provides a reliable sensing platform that will allow label-free and marker-free detection. By exploiting characteristics unique to AlGaN/GaN based HEMT devices, a floating gate configuration is employed to allow reliable sensing without the need for any reference electrode. Self-assembled monolayers (SAM) are formed at the gate surface by using a crosslinker (DSP) to allow for appropriate immobilization of target antibodies. A theoretical analytical and numerical model is developed …
Evaluation Of Security Availability Of Data Components For A Renewable Energy Micro Smart Grid System, Leonel Aguilera Zambrano
Evaluation Of Security Availability Of Data Components For A Renewable Energy Micro Smart Grid System, Leonel Aguilera Zambrano
Theses and Dissertations - UTB/UTPA
In this thesis, we study the development and security testing of photovoltaic data collection system. With the introduction of the smart grid concept, a lot of research has been done on the communication aspect of energy production and distribution throughout the power network. For Smart Grid, Internet is used as the communication medium for specific required services and for data collection. Despite all the advantages of the Smart Grid infrastructure, there is also some security concern regarding the vulnerabilities associated with internet access. In this thesis, we consider security testing of the two most popular and globally deployed web server …
Subthreshold 3 Phase Mixers, Jesus Angel Torres
Subthreshold 3 Phase Mixers, Jesus Angel Torres
Theses and Dissertations - UTB/UTPA
This thesis will discuss subthreshold FET mixers with a focus on conversion loss derivations. To begin understanding the mixers, a look into the FET model is first taken in Chapter II. Then in Chapter III, a single FET device mixer is studied and its conversion loss is found from its small-signal model. The chapter will then include a two FET device mixer and a four device FET mixer. Finally a new type of mixer will be discussed in Chapter IV. The new type of mixer is a 3 phase mixer with the phase angles being 0°, 120°, and 240°. The …
Development Of Laboratory Based Smart Micro Grid To Be Used As An Educational Tool, Jose L. Sanchez
Development Of Laboratory Based Smart Micro Grid To Be Used As An Educational Tool, Jose L. Sanchez
Theses and Dissertations - UTB/UTPA
The increasing trend of the energy industry to move towards a new smart power grid has pushed researchers to address the challenges that this represents. Universities all around the world are also under pressure to better prepare their students to meet the challenges that await them with this new technology and techniques. The work presented on this thesis was motivated by the current need of the electrical engineering curriculum to include new material into their current courses. A laboratory based smart micro grid was created by applying several concepts and techniques currently being adopted by the energy industry to make …
Design For Soft Error Tolerance In Fpga-Implemented Asynchronous Circuits, Yu Bai
Design For Soft Error Tolerance In Fpga-Implemented Asynchronous Circuits, Yu Bai
Theses and Dissertations - UTB/UTPA
This research in its present form is the result of experimentation on effect of soft error in FPGA-implemented asynchronous circuit. The conclusion are drawn that asynchronous circuit are much easier to detect soft error than synchronous circuits. The asynchronous circuit is implemented in FPGA with software fault injection method to analyze the behavior of soft error generation in FPGA implementation asynchronous circuits. The proposed detection circuit can detect all soft errors that generated in FPGA-implemented asynchronous circuit. The contributions include: investigation of FPGA structure, investigation of soft error model in FPGA, mechanism of FPGA implemented asynchronous circuit, behavior of soft …
Photolithographic Fabrication Of 3d Penrose-Like Quasi-Photonic Crystal Polymeric Templates Utilizing Lab-Made Phasemask, Faraon Torres-Lazos
Photolithographic Fabrication Of 3d Penrose-Like Quasi-Photonic Crystal Polymeric Templates Utilizing Lab-Made Phasemask, Faraon Torres-Lazos
Theses and Dissertations - UTB/UTPA
Photonic crystals (PhC) have recently become of great interest because of their potential as replacement of electronics and/or supplement to semiconductors technology. The PhC’s capability to make compact integrated optical circuits has already made possible the laboratory manufacture of an array of different types of optical waveguides, cavities and filters. The work presented here aimed to simultaneously fabricate a 3D-PhC templates employing six-beam holographic lithography. The basic procedures included recording gratings using interference field of laser sources in a photoresist coating on a glass substrate. The manufacturing method utilized only one optical element, a phasemask, drastically reducing the complexity of …
Experimental Evaluation Of Select Servers And Firewalls Under Denial Of Service Security Attacks, Raja Sekhar Reddy Gade
Experimental Evaluation Of Select Servers And Firewalls Under Denial Of Service Security Attacks, Raja Sekhar Reddy Gade
Theses and Dissertations - UTB/UTPA
Internet security requires newer prevention mechanisms to be implemented on web-servers and routers. Firewall/Intrusion Prevention mechanisms (IPS) can be deployed on host servers or routers as an added line of defense against Internet attacks. In this thesis, we evaluate performance of security mechanisms provided by these devices against Distributed Denial of Service (DDoS) attacks. The host based firewalls on Windows servers-2003 and 2008 were evaluated. In this thesis, we also evaluated Juniper Networks Netscreen-5GT firewall/IPS, and Cisco ASA-5510/IPS that are used in protecting web-servers against DDoS attacks. It was found that the host based firewalls and protection mechanisms on the …
Security Vulnerability Evaluation Of Popular Personal Firewalls And Operating Systems, Sirisha Surisetty
Security Vulnerability Evaluation Of Popular Personal Firewalls And Operating Systems, Sirisha Surisetty
Theses and Dissertations - UTB/UTPA
In this thesis, experimental evaluation of security vulnerabilities has been performed under DoS attacks for popular personal firewalls from McAfee, Norton and Kaspersky; and for operating systems namely Apple’s Leopard and SnowLeopard, and Microsoft’s Windows XP and Windows 7. Our experimental results show that the firewalls and operating systems behave differently under a given DoS attack. Some of the firewalls crashed under certain DoS attacks especially when they were configured to prevent and block packets belonging to such attacks. Operating systems evaluated in this thesis were also found to have different built-in security capabilities, and some of them even crashed …
An Improved Wideband Vivaldi Antenna Design, Fang Chen
An Improved Wideband Vivaldi Antenna Design, Fang Chen
Theses and Dissertations - UTB/UTPA
The objectives of this thesis are to 1) determine how Vivaldi antenna parameters affect the performance and 2) design a Vivaldi antenna with improved overall performance over existing designs. The methodology is to divide the Vivaldi antenna into two parts consisting of microstrip-to-slotline transition and tapered curve part. This has great advantages in finding the relationships between the different antenna parameters and the antenna performance. By combining the methods of improving the impedance- and usable gain bandwidth concluded by the parameter study on the two individual parts, a final Vivaldi antenna design with 10:1 bandwidth is achieved in terms of …
The Implementation And Analysis Of Through Wall Radar Systems, Xiaohui Wang
The Implementation And Analysis Of Through Wall Radar Systems, Xiaohui Wang
Theses and Dissertations - UTB/UTPA
Through wall radar detecting, locating, imaging and tracking is a topic of current research interest in connection with law enforcement, urban area operations and search and rescue missions. Up to now, three different radar techniques are employed in through wall radar systems, including impulse through wall radar, continuous wave radar and swept frequency radar. In this thesis, we set out to give a comparison of these three kinds of through wall radar systems. First,we studied the challenges caused by the wall in through wall radar systems. Second,we implemented these three kinds of through wall radar system. In each kind of …
Asynchronous Designs On Fpga With Soft Error Tolerance For Security Algorithms, Deepya Reddy Nalubolu
Asynchronous Designs On Fpga With Soft Error Tolerance For Security Algorithms, Deepya Reddy Nalubolu
Theses and Dissertations - UTB/UTPA
Asynchronous methodologies, such as Null Convention Logic (NCL), have tremendous potential in implementing digital logic. It is essential to design complex asynchronous circuits using commercial Electronic Design Automation (EDA) tools. The main focus of this thesis is to design NCL circuits using VHDL and implementing them on FPGAs. The major contributions of this thesis include: 1) Developing a methodology of designing NCL circuits with VHDL and applying it successfully to all practical designs in this thesis. 2) As an example, the NCL circuit for DES (Data Encryption Standard) algorithm has been designed and simulated using VHDL and the implementation issues …
Uwb Antennas For Medical Imaging, Khabat Ebnabbasi
Uwb Antennas For Medical Imaging, Khabat Ebnabbasi
Theses and Dissertations - UTB/UTPA
Ultra-Wide Band (UWB) Microwave for imaging applications; especially in the medical field, is a new method to overcome the inherent invasive features of X-ray imaging. In this work a new systematic and detailed design for the Tapered Slot Antenna (TSA) as a UWB antenna in microwave imaging systems for medical applications is presented. Among TSAs, the Vivaldi antenna was selected and the reasons to replace the horn antenna imaging systems are illustrated. In the first chapter the previous designs for microwave imaging and the outline of this work are given, Chapter Two covers the design of the Vivaldi antenna's different …
The Optimization Of Amplifiers For Uwb Applications, Kyoung D. Kim
The Optimization Of Amplifiers For Uwb Applications, Kyoung D. Kim
Theses and Dissertations - UTB/UTPA
Optimizations of 0.18 μm and 0.5 μm MOSFET amplifiers without using inductors for UWB applications are presented. A 3 dB bandwidth from 3.1 GHz to 9.9 GHz with minimum 9.6 dB of transducer gain at 10.6 GHz and approximate 92.8 mWatts of total power consumption are achieved. The source and load impedances were 50 ohms. Also, the number of capacitors and resistors has been minimized. To predict characteristics more precisely, the pad capacitance is added to the output port. In addition, a different feedback topology is presented which gives a lower Noise Figure with maximum 7.73 dB at 10.6 GHz …
Moving And Stationary Target Acquisition Radar Image Enhancement Through Polynomial Windows, Rajarajeswari Devarajulu
Moving And Stationary Target Acquisition Radar Image Enhancement Through Polynomial Windows, Rajarajeswari Devarajulu
Theses and Dissertations - UTB/UTPA
The Fourier transform involved in synthetic aperture radar (SAR) imaging causes undesired sidelobes which obscure weak backscatters and affect the image clarity. These sidelobes can be suppressed without deteriorating the image resolution by smoothing functions known as windowing or apodization. Recently, the theory of orthogonal polynomials has gained considerable attention in signal processing applications. The window functions that are derived from the orthogonal polynomials have interesting sidelobe roll-off properties for better sidelobe apodization, hence it can be used for radar image enhancement. In this work, a new window is constructed from Jacobi orthogonal polynomials and its performance in SAR imaging …
Design And Performance Evaluation Of Switching Architectures For High-Speed Internet, Alvaro Munoz
Design And Performance Evaluation Of Switching Architectures For High-Speed Internet, Alvaro Munoz
Theses and Dissertations - UTB/UTPA
The motivation for this thesis is the desire to build faster and scalable routers that efficiently handle the exponential traffic growth in the Internet. The Internet forwards information through a mesh of routers and switches, which has to keep up with the increasing demands of traffic. Shared-memory based switches are known to provide the best throughput-delay performance for a given memory size. In this thesis performance of commonly used memory-sharing schemes for the shared memory switches are evaluated under balanced and unbalanced bursty traffic. The scalability of shared-memory switches has been a research issue for quite sometime. One approach is …
Rf Cmos Receiver Front-End Using A Reflex Amplifier, Radovan Kuzet
Rf Cmos Receiver Front-End Using A Reflex Amplifier, Radovan Kuzet
Theses and Dissertations - UTB/UTPA
A concept for an RF-CMOS receiver with reflex topology is developed and tested, using OrCad as the primary design and simulation tool. The main idea of the reflex topology is to reuse a Low Noise Amplifier (LNA) stage in the circuit and thus eliminate one high power consumption stage. A Gilbert cell is used for down conversion, with the benefit of low noise and low power while maintaining gain. A set of passive diplexers allows reuse of the LNA at the RF and IF. The complete circuit was simulated using 0.18 micron and 0.5 micron AMI technology. Parameters for the …