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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Cmos Integrated Sensor Readout Circuitry For Dna Detection Applications

Musayev, Javid 01 September 2011 (has links) (PDF)
This study presents a CMOS integrated sensor chip suitable for sensing biological samples like DNA. The sensing part of the chip consists of a 32 X 32 pixel array with a 15 &micro / m pixel pitch. Pixels have 5 &micro / m X 5 &micro / m detector electrodes implemented with the top metal of the CMOS process, and they are capable of detecting charge transferred or induced on those electrodes with a very high sensitivity. This study also includes development of an external electronics containing ADC for analog to digital data conversion. This external circuitry is implemented on a PCB compatible with the Opal Kelly XM3010 FPGA that provides data storage and transfer to PC. The measured noise of the overall system is 6.7 e- (electrons), which can be shrunk down to even 5.1 e- with an over sampling rate. This kind of sensitivity performance is very suitable for DNA detection, as a single nucleotide of a DNA contains 1 or 2 e- and as 10 to 20 base pair long DNA&rsquo / s are usually used in microarray applications. The measured dynamic range of the system is 71 dB, in other words, at most 24603 e- per frame (20 ms) can be detected. The measured leakage is 31 e-/frame, but this does not have a dramatic effect on the sensitivity of the system, noting that the leakage is a predictable quantity. DNA detection tests are performed with the chip in addition to electronic performance measurements. The surface of the chip is covered with a nitride passivation layer to prevent the pixel crosstalk and is modified with an APTES polymer for suitable DNA immobilization. DNA immobilization and hybridization tests are performed with 5&rsquo / -TCTCACCTTC-3&rsquo / probe and its complementary 3&rsquo / -AGAGTGGAAG-5&rsquo / target sequences. Hybridization performed in 1 pM solution is shown to have a larger steady state leakage than the immobilization in a 13 &micro / M solution, implying the ability to differentiate between the full match and full mismatch sequences. To best of our knowledge, the measured pM sensitivity has not yet been reported with any label free CMOS DNA microarrays in literature, and it is comparable with the sensitivity of techniques like QCM or the fluorescence imaging. The 1 pM sensitivity is not a theoretical limit of the sensor, since theoretically the sensitivity level of 6.7 e- can offer much better results, down to the aM level, as far as the noise of electronics is considered, nevertheless the sensitivity is expected to be limited by DNA immobilization and hybridization probabilities which are determined by the surface modification technique and applied protocol. Improving those can lead to much smaller detection limits, such as aM level as stated above.
62

3d Face Recognition With Local Shape Descriptors

Inan, Tolga 01 September 2011 (has links) (PDF)
This thesis represents two approaches for three dimensional face recognition. In the first approach, a generic face model is fitted to human face. Local shape descriptors are located on the nodes of generic model mesh. Discriminative local shape descriptors on the nodes are selected and fed as input into the face recognition system. In the second approach, local shape descriptors which are uniformly distributed across the face are calculated. Among the calculated shape descriptors that are discriminative for recognition process are selected and used for three dimensional face recognition. Both approaches are tested with widely accepted FRGCv2.0 database and experiment protocol. Reported results are better than the state-of-theart systems. Recognition performances for neutral and non-neutral faces are also reported.
63

Pid And Lqr Control Of A Planar Head Stabilization Platform

Akgul, Emre 01 September 2011 (has links) (PDF)
During the uniform locomotion of legged robots with compliant legs, the body of the robot exhibits quasi-periodic oscillations that have a disturbing eect on dierent onboard sensors. Of particular interest is the camera sensor which suers from image degradation in the form of motion-blur as a result of this camera motion. The eect of angular disturbances on the camera are pronounced due to the perspective projection property of the camera. The thesis focuses on the particular problem of legged robots exhibiting angular body motions and attempts to analyze and overcome the resulting disturbances on a camera carrying platform (head). Although the full problem is in 3D with three independent axes of rotation, a planar analysis provides signicant insight into the problem and is the approach taken in the thesis. A carefully modeled planar version of an actual camera platform with realistic mechanical and actuator selections is presented. Passive (ltering) and active (controller) approaches are discussed to compensate/cancel motion generated disturbances. We consider and comparatively evaluate PID and LQR based active control. Since PID has the limitation of controlling only one output, PID-PID control is considered to iv control two states of the model. Due to its state-space formulation and the capability of controlling an arbitrary number of states, LQR is considered. In addition to standard reference signals, Gyroscope measured disturbance signals are collected from the actual robot platform to analyze the bandwidth and test the performance of the controllers. Inverted pendulum control performance is evaluated both on a Matlab-Simulink as well as a precise electro-mechanical test setup. Since construction of the planar head test setup is in progress, tests are conducted on simulation.
64

An Fpga Based Bldc Motor Control System

Uygur, Serdar 01 March 2012 (has links) (PDF)
In this thesis, position and current control systems for a brushless DC (Direct Current) motor are designed and integrated into one FPGA (Field Programmable Gate Array) chip. Experimental results are obtained by driving the brushless DC motors of Control Actuation System of a guided missile. Because of their high performance, brushless DC motors are widely used in Control Actuation Systems of guided missiles. In order to control the motor torque, current controller is designed and implemented in the FPGA. Position controller is designed to fulfill the position commands. A soft processor in the FPGA is used to connect and configure the current controller, position sensor interfaces and communication modules such as UART (Universal Asynchronous Receiver Transmitter) and Spacewire. In addition / position controller is implemented in the soft processor in the FPGA. An FPGA based electronic board is designed and manufactured to implement control algorithms, power converter circuitry and to perform other tasks such as communication with PC (Personal Computer). In order to monitor the behavior of the controllers in real time and to achieve performance tests, a graphical user interface is provided.
65

A Comparative Study On Pose Estimation Algorithms Using Visual Data

Cetinkaya, Guven 01 February 2012 (has links) (PDF)
Computation of the position and orientation of an object with respect to a camera from its images is called pose estimation problem. Pose estimation is one of the major problems in computer vision, robotics and photogrammetry. Object tracking, object recognition, self-localization of robots are typical examples for the use of pose estimation. Determining the pose of an object from its projections requires 3D model of an object in its own reference system, the camera parameters and 2D image of the object. Most of the pose estimation algorithms require the correspondences between the 3D model points of the object and 2D image points. In this study, four well-known pose estimation algorithms requiring the 2D-3D correspondences to be known a priori / namely, Orthogonal Iterations, POSIT, DLT and Efficient PnP are compared. Moreover, two other well-known algorithms that solve the correspondence and pose problems simultaneously / Soft POSIT and Blind- PnP are also compared in the scope of this thesis study. In the first step of the simulations, synthetic data is formed using a realistic motion scenario and the algorithms are compared using this data. In the next step, real images captured by a calibrated camera for an object with known 3D model are exploited. The simulation results indicate that POSIT algorithm performs the best among the algorithms requiring point correspondences. Another result obtained from the experiments is that Soft-POSIT algorithm can be considered to perform better than Blind-PnP algorithm.
66

Medical Electro-thermal Imaging

Carlak, Hamza Feza 01 February 2012 (has links) (PDF)
Breast cancer is the most crucial cancer type among all other cancer types. There are many imaging techniques used to screen breast carcinoma. These are mammography, ultrasound, computed tomography, magnetic resonance imaging, infrared imaging, positron emission tomography and electrical impedance tomography. However, there is no gold standard in breast carcinoma diagnosis. The object of this study is to create a hybrid system that uses thermal and electrical imaging methods together for breast cancer diagnosis. Body tissues have different electrical conductivity values depending on their state of health and types. Consequently, one can get information about the anatomy of the human body and tissue&rsquo / s health by imaging tissue conductivity distribution. Due to metabolic heat generation values and thermal characteristics that differ from tissue to tissue, thermal imaging has started to play an important role in medical diagnosis. To increase the temperature contrast in thermal images, the characteristics of the two imaging modalities can be combined. This is achieved by implementing thermal imaging applying electrical currents from the body surface within safety limits (i.e., thermal imaging in active mode). Electrical conductivity of tissues changes with frequency, so it is possible to obtain more than one thermal image for the same body. Combining these images, more detailed information about the tumor tissue can be acquired. This may increase the accuracy in diagnosis while tumor can be detected at deeper locations. Feasibility of the proposed technique is investigated with analytical and numerical simulations and experimental studies. 2-D and 3-D numerical models of the female breast are developed and feasibility work is implemented in the frequency range of 10 kHz and 800 MHz. Temporal and spatial temperature distributions are obtained at desired depths. Thermal body-phantoms are developed to simulate the healthy breast and tumor tissues in experimental studies. Thermograms of these phantoms are obtained using two different infrared cameras (microbolometer uncooled and cooled Quantum Well Infrared Photodetectors). Single and dual tumor tissues are determined using the ratio of uniform (healthy) and inhomogeneous (tumor) images. Single tumor (1 cm away from boundary) causes 55 &deg / mC temperature increase and dual tumor (2 cm away from boundary) leads to 50 &deg / mC temperature contrast. With multi-frequency current application (in the range of 10 kHz-800 MHz), the temperature contrast generated by 3.4 mm3 tumor at 9 mm depth can be detected with the state-of-the-art thermal imagers.
67

Qoc And Qos Bargaining For Message Scheduling In Networked Control Systems

Senol, Sinan 01 June 2012 (has links) (PDF)
Networked Control Systems (NCS) are distributed control systems where the sensor signals to the controllers and the control data to the actuators are enclosed in messages and sent over a communication network. On the one hand, the design of an NCS requires ensuring the stability of the control system and achieving system response that is as close as possible to that of an ideal system which demands network resources. On the other hand, these resources are limited and have to be allocated efficiently to accommodate for future system extensions as well as applications other than control purpose. Furthermore the NCS design parameters for the control system messages and the message transmission over the network are interdependent. In this thesis, we propose &ldquo / Integrated NCS Design (INtERCEDE: Integrated NEtwoRked Control systEm DEsign)&rdquo / a novel algorithmic approach for the design of NCS which ensures the stability of the control system, brings system response to that of an ideal system v as close as desired and conserves network bandwidth at the same time. The core of INtERCEDE is a bargaining game approach which iteratively calculates the message parameters and network service parameters. Our experimental results demonstrate the operation of INtERCEDE and how it computes the optimal design parameters for the example NCS.
68

Short Range Thrusting Projectile Tracking

Bilgin, Ozan Ozgun 01 September 2012 (has links) (PDF)
Short range thrusting projectiles are one of the various threats against armored vehicles and helicopters on the battlefield. Developing a countermeasure for this kind of projectiles is very crucial since they are vast in number and easy to operate on the battlefield. A countermeasure may consist of fire point prediction of the projectile and attack the launcher of it, or it may be the impact point prediction of the projectile and apply a hard-kill counter measure on its way to the ally target. For both of the countermeasure concepts, dynamics and parameters of the projectile must be estimated precisely. In this thesis, dynamic models for thrusting and ballistic flight modes of thrusting projectile are obtained. Three different tracking filters are suggested for precise tracking of the projectiles and their estimation performances are compared. These filters are the Extended Kalman Filter (EKF), the Particle Filter (PF) and the Marginalized Particle Filter (MPF).
69

Development Of A Tool For Web Based Control Engineering Education

Cigeroglu, Huseyin 01 August 2004 (has links) (PDF)
It is obvious that learning is more productive with visual mediums and simulations. Especially in technical subjects, this approach is more important. Visual modification of parameters in a control system provides many benefits both in analyzing the system and in learning process. Additionally if this material is published on the internet, students can reach anywhere anytime to this material. This thesis describes a Web-based system developed for control engineering education for both the instructor and the student. The system will generate learning material according to the instructor&rsquo / s requests. Instructors will design the system and define the borders to help students to learn rapidly the subject of the lesson. They will decide on the functions and which variables can be played with and present them to the students. This work will help the students that take the basic courses of control engineering. Students will interactively experiment with the system. They will see the effect by changing the variables via sliders of certain functions (e.g. step, bode, root locus...). The system is developed with the programming language JAVA to run over the internet and to be platform independent.
70

Avalanche Properties And Randomness Of The Twofish Cipher

El, Omer 01 December 2004 (has links) (PDF)
In this thesis, one finalist cipher of the Advanced Encryption Standard (AES) block cipher contest, Twofish proposed by Schneier et al, is studied in order to observe the validity of the statement made by Arikan about the randomness of the cipher, which contradicts National Institute of Standards and Technology (NIST)&rsquo / s results. The strength of the cipher to cryptanalytic attacks is investigated by measuring its randomness according to the avalanche criterion. The avalanche criterion results are compared with those of the Statistical Test Suite of the NIST and discrepancies in the second and third rounds are explained theoretically.

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