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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.

Experiments on the vibration control of a flexible structure using FPGA

Chaudhari, Devendra 24 February 2016 (has links)
<p> The goal of this project is to develop, implement and test experimentally a state-feedback controller for the vibration control of a flexible structure, using an Active Mass Damper (AMD). Based on a previously developed model of the structure, a state-feedback controller with full observer has been implemented in the LabView (Laboratory Virtual Instrument Engineering Workshop) computational environment using the myRIO FPGA board (Field Programmable Gate Array). Experimental results show that the controller improves the structural response significantly by reducing the amplitude and duration of the response when the structure is subject to random earthquake-like excitations. </p>

Gray-cast iron classification based on graphite flakes using image morphology and neural networks

Yeliyur Siddegowda, Darshan 25 February 2016 (has links)
<p> Gray-cast iron is an iron carbon alloy which is regularly used in manufacturing processes. Carbon is distributed in the iron material in the form of graphite. The distribution of the graphite flakes in the alloy contributes greatly towards the chemical and physical properties of the metal alloy. Thus it is important to identify and classify the Gray-cast iron based on the morphological parameters of the graphite flakes. Gray-Cast iron is classified into five types in ISO-945 represented with the letters A through E. These five classes possess different structures or distributions of the graphite flakes. The current project presents an automated classification method using image processing and machine learning algorithms. The method presented here obtains the required parameters from the microstructure through image morphological operations. The image information is subsequently fed through a supervised machine learning algorithm which is trained using parameters such as area of the flakes, perimeter, minimum inter-particle distance and chord length from over twenty samples. The algorithm calculates the percentage of the type of the flakes present in the given image. The simulation is done in MATLAB and was tested for six images in each class. Class C and D were classified with 100 percent accuracy, Class A and B were classified with accuracy of 82 percent and Class E was identified with accuracy of 68 percent.</p>

Multi-sensor-based occupancy monitoring for energy efficient smart buildings based on internet of things

Pradeep Kumar, Harshvardhan 13 April 2016 (has links)
<p> The Internet of Things (IoT) is the network of physical objects embedded with sensors and connectivity. The ubiquitous nature of IoT nodes will allow the deployment of embedded sensors, actuators, cameras, mobile phones, and Radio Frequency Identification Devices (RFID) in buildings for monitoring the condition of the building and the well being of the occupants. The current project presents the design and implementation of a sensor network within the IoT framework, using infrared (IR) sensors to monitor the number of visitors in the building and their distribution across predetermined zones. Using IR sensor data the Demand-Controlled Ventilation (DCV) units on each floor are controlled based on zone occupancies. The occupancy data are displayed on a mobile phone or PC using a Wireless Fidelity (WiFi) module. The devices in the experimental implementation of this network include IR, temperature, and CO2 sensors, interfaced to a microcontroller. Experimental testing shows that the network performs flawlessly and reliably.</p>

Skill Transfer between Industrial Robots by Learning from Demonstration

Li, Mengtang 28 March 2016 (has links)
Industrial robots are the key role in modern manufacture. In order to allow different robots to perform the same task, they must be programmed manually which is time-consuming and cumbersome. The ability to transfer robotic skills between heterogeneous robots would provide significances to industry. This paper presents a prototype control architecture for industrial robots which allows multiple heterogeneous robots of different morphologies to perform the same task without manually programming each robot separately. We selected three articulated industrial manipulators with different degree of freedoms (Yaskawa Motoman HP3JC, Universal Robot UR5 and Rethink Robotics Baxter) to test our approach. Two simple assembly tasks were chosen for analysis and implementation. Results indicate that our approach works well with some errors. Maximum and average position mismatch errors for UR5 are 4.938 cm and 4.431 cm. For Baxter, maximum and average position mismatch errors are 8.8797 cm and 3.785 cm. Baxter has a different range of motion therefore some places could not be reached with it.

Enhancing Light-matter Interaction in Ultrathin Films using Optical Nanostructures

Wang, Wenyi 09 April 2016 (has links)
Ultrathin films including two-dimensional materials and transparent conductive oxide nano-films are excellent candidates for future optoelectronic devices. However, external quantum efficiencies of the ultrathin film-based devices are typically limited due to their small physical thickness. The practical application of these ultrathin films therefore requires integration with optical nanostructures to enhance light-matter interaction in the thin films. In this work, I will present my efforts to modify the interaction between light and ultrathin films using different approaches, including hot electron injection, integration with Fano-resonant photonic crystals, and use a hybrid mode combining an epsilon-near-zero mode with a Huygensâ dielectric metasurface. The optoelectronic devices demonstrated based on these integrations result in significant increases in absorption, photoresponsivity, and modulation depth.

Development and assessment of a control approach for a lower-limb exoskeleton for use in gait rehabilitation post stroke

Murray, Spencer Ambrose 18 April 2016 (has links)
Lower-limb weakness or paralysis is a common impairment following stroke. In recent years numerous robotic-assisted systems have been developed to aid in post-stroke gait rehabilitation. The controllers developed for these systems have nearly all consisted of traditional or modified trajectory-based control systems which guide a patientâs limbs through a kinematically improved gait cycle. Controllers which do not operate on a trajectory basis may offer numerous advantages, especially when implemented on an overground (as opposed to treadmill-based) robotic system. This thesis describes the development and evaluation of a non-trajectory-based controller for use in post-stroke gait training. The controller has been implemented on a lower-limb robotic exoskeleton and tested with several subjects recovering from stroke. Subjects were able to improve gait speed and stride length after practicing overground gait in the exoskeleton.

Soft error aware physical synthesis

Assis, Thiago Rocha de 04 December 2015 (has links)
To allow accurate analysis of Soft Errors by Electronic Design Automation (EDA) tools, analytical models were developed to estimate electrical characteristics of the single event. The Ambipolar-Diffusion-With-Cutoff (ADC) model was extended in this work to model charge sharing, thus allowing accurate charge estimation by EDA tools An Single Event Transient (SET) pulse width estimation methodology was developed to model the Standard Cells response to the soft error. Combining these models along with circuit masking probabilities, the circuit soft-error cross-section is estimated. These soft error models are then integrated into an automatic standard cell placement tool based on Quadratic Optimization. Results show the impact of Physical Synthesis electrical correction techniques, such as Buffering, Gate Cloning and Gate Sizing, to the circuit soft error cross-section. Furthermore, an algorithm to reduce the circuit soft error cross-section by optimizing the Tap Cell placement was also developed and demonstrated. Results from this thesis provide key insights to control the circuit soft error cross-section during the Physical Synthesis design flow for integrated circuits at the most advanced technology nodes.

Finite Precision Error in FPGA Measurement

AHMAD, SHOAIB January 2015 (has links)
Finite precision error in digital signal processing creates a threshold of quality of the processed signal. It is very important to agree on the outcome while paying in terms of power and performance. This project deals with the design and implementation of digital filters FIR and IIR, which is further utilized by a measurement system in order to correctly measure different parameters. Compared to analog filters, these digital filters have more precise and accurate results along with the flexibility of expected hardware and environmental changes. The error is exposed and the filters are implemented to meet the requirements of a measurement system using finite precision arithmetic and the results are also verified through MATLAB. Moreover with the help of simulations, a comparison between FIR and IIR digital filters have been presented. / <p>Passed</p> / Digital filters and FPGA

Simulation for non-congestion losses control over Mobile Ad-Hoc Network using Transmission Control Protocol

Kuditipudi, Sasank 09 February 2016 (has links)
<p> Mobile Ad-hoc Network (MANET) is a group of individual mobile nodes that exhibit mobility, which results in network congestion. The nodes in MANET are continuously moving with change in network topology that results in significant network congestion. Transmission Control Protocol (TCP) is the most popular connection oriented transport layer protocol used today. The TCP when applied over MANET faces challenges, such as congestion and non-congestion losses. We are concentrating to distinguish between these losses and overcome the non-congestion losses.</p><p> The current project presents results on the performance evaluation of various TCP implementations, as measured in terms of the following parameters: end-to-end delay; throughput; network overhead; and packet delivery ratio. Simulations of applying the various TCP schemes over MANET have been performed using the Network Simulator (NS2), and simulation results including comparisons between the different TCP schemes are presented.</p>

Observer Based Controller Design For Max-Plus Linear Systems With Applications

Efenedo, Efegbare 09 August 2016 (has links)
<p> Max-plus algebra is a suitable algebraic setting to model discrete event systems involving synchronization and delay phenomena which are often found in transportation networks, communications systems and manufacturing systems. One way of controlling this kind of systems consists in choosing the dates of input events in order to achieve the desired performances, e.g., to obtain output events in order to respect given dates. This kind of control is optimal, according to a just-in-time criterion, if the input-event dates are delayed as much as possible while ensuring the output events to occur before a desired reference date. This thesis presents the observer-based controller for max-plus linear systems where only estimations of system states are available for the controller, which is solved in two steps: first, an observer computes an estimation of the state by using the input and the output measurements, then, this estimated state is used to compute the state-feedback control action. It is shown that the optimal solution of this observer-based control problem leads to a greater control input than the one obtained with the output feedback strategy. Moreover, for the uncertain max-plus linear systems have varying processing time between each transition, this thesis presents robust observer-based controller towards optimizing process scheduling of a timed event systems according to the just in time criterion. Applications of the main results are illustrated in a high throughput screening system in drug discovery and a transportation network.</p>

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