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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.
321

Hard Real Time guarantees using Switched Ethernet and distributed scheduling (EDF)

KinShe, Kam, Bhavani Chandrasekhar, Kondreddi January 2006 (has links)
Ethernet technology is being accepted by industrial community due to its open standardization and low cost. To meet the requirements of industrial applications, a switched Ethernet network with hard real time guarantees using relative deadlines is presented as a first step to verify the functionality. The goal of the project was primarily to implement a real-time switched Ethernet with EDF (Earliest Deadline First) scheduling algorithm. In this project, the function simulations of real-time switched Ethernet with distributed control software have been implemented, by using a standard switch with priority-queues and the distributed software, as well as EDF-scheduled TDMA (Time Division Medium Access). The network topology is the star type. There is no extra hardware added into the switch and the nodes. All functions are implemented by software and the setting in the switch. The project focuses on hard real-time service guarantees but soft real-time traffic and non real-time traffic, as well as real time administration are also taken into the consideration. Our simulations show that 100 percent of the network usage could be scheduled and the result of deterministic real-time properties of the system are achieved as expected.
322

Implementing Real-Time Video Deblocking in FPGA Hardware

Hansen, Martin January 2007 (has links)
Video compression techniques are commonly used to meet the increasing demands for the storage and transmission of digital video content. Popular video compression techniques such as MPEG video encoding make use of block-transform coding algorithms which are susceptible to blocking artifacts. These artifacts can be reduced using a deblocking process, of which there are many. However, those deblocking algorithms which provide noticeable improvements in visual quality also tend to be computationally expensive and unsuitable for real-time video use. This dissertation selects and examines an appropriate algorithm for real-time video deblocking applications, and describes its hardware implementation on a Altera Cyclone II FPGA. The chosen algorithm is based on the concept of shifted thresholding; it reduces computational complexity by several means, such as by using only integer arithmetic and by replacing division operations with bit shifting. The implementation leverages the reduced hardware complexity of the chosen algorithm to cost-effectively implement real-time video deblocking.
323

Vector Graphics for Real-time 3D Rendering

Qin, Zheng January 2009 (has links)
Algorithms are presented that enable the use of vector graphics representations of images in texture maps for 3D real time rendering. Vector graphics images are resolution independent and can be zoomed arbitrarily without losing detail or crispness. Many important types of images, including text and other symbolic information, are best represented in vector form. Vector graphics textures can also be used as transparency mattes to augment geometric detail in models via trim curves. Spline curves are used to represent boundaries around regions in standard vector graphics representations, such as PDF and SVG. Antialiased rendering of such content can be obtained by thresholding implicit representations of these curves. The distance function is an especially useful implicit representation. Accurate distance function computations would also allow the implementation of special effects such as embossing. Unfortunately, computing the true distance to higher order spline curves is too expensive for real time rendering. Therefore, normally either the distance is approximated by normalizing some other implicit representation or the spline curves are approximated with simpler primitives. In this thesis, three methods for rendering vector graphics textures in real time are introduced, based on various approximations of the distance computation. The first and simplest approach to the distance computation approximates curves with line segments. Unfortunately, approximation with line segments gives only C0 continuity. In order to improve smoothness, spline curves can also be approximated with circular arcs. This approximation has C1 continuity and computing the distance to a circular arc is only slightly more expensive than computing the distance to a line segment. Finally an iterative algorithm is discussed that has good performance in practice and can compute the distance to any parametrically differentiable curve (including polynomial splines of any order) robustly. This algorithm is demonstrated in the context of a system capable of real-time rendering of SVG content in a texture map on a GPU. Data structures and acceleration algorithms in the context of massively parallel GPU architectures are also discussed. These data structures and acceleration structures allow arbitrary vector content (with space-variant complexity, and overlapping regions) to be represented in a random-access texture.
324

Reducing the effect of network delay on tightly-coupled interaction

Stuckel, Dane Joshua 31 March 2008 (has links)
Tightly-coupled interaction is shared work in which each persons actions immediately and continuously influence the actions of others. Tightly-coupled interaction is a hallmark of expert behaviour in face-to-face activity, but becomes extremely difficult to accomplish in distributed groupware. The main cause of this difficulty is network delay even amounts as small as 100ms that disrupts peoples ability to synchronize their actions with another person. To reduce the effects of delay on tightly-coupled interaction, I introduce a new technique called Feedback-Feedthrough Synchronization (FFS). FFS causes visual feedback from an action to occur at approximately the same time for both the local and the remote person, preventing one person from getting ahead of the other in the coordinated interaction. I tested the effects of FFS on group performance in several delay conditions, and my study showed that FFS substantially improved users performance: accuracy was significantly improved at all levels of delay, and without noticeable increase in perceived effort or frustration. Techniques like FFS that support the requirements of tightly-coupled interaction provide new means for improving the usability of groupware that operates on real-world networks.
325

Optimization and validation of the method lactose intolerance genotyping with real-time PCR

Stenberg, Jenny January 2011 (has links)
Abstract Primary lactose intolerance has been associated with a single nucleotide polymorphism located upstream of the lactase gene. The most common diagnostic tests for lactose intolerance are time-consuming and the patient is not allowed to eat and drink for 12 hours before the test is carried out. A method that can establish the genotype would be an easier way of diagnosing lactose intolerance compared to fenotypic lactose intolerance tests. Optimization and validation of a previously published method was performed with real-time polymerase chain reaction. We used whole blood from de-identified blood donors. During the optimization and validation we used a positive control, genotype C/T from Laboratoriemedicin Västernorrland, Sundsvall. The whole-blood was extracted using the MagNa Pure LC instrument. The reagent used was KAPA PROBE FAST qPCR Master Mix. The optimized program for real-time PCR was established to be 95°C 3min [95°C x 3sec, 55°C x 20sec, detection, 72°C x 15sec] x 50 cycles. Optimal probe concentration was found to be 0.2µM and primer concentration will be 0.5µM. This genotyping method is a good first-stage screening test for lactoseintolerance. Before it can be used as a routine method further validation will be necessary in order to ensure that the evaluation of the results can be done in an easy and secure way.
326

Evaluation and Comparison of Beamforming Algorithms for Microphone Array Speech Processing

Allred, Daniel Jackson 11 July 2006 (has links)
Recent years have brought many new developments in the processing of speech and acoustic signals. Yet, despite this, the process of acquiring signals has gone largely unchanged. Adding spatial diversity to the repertoire of signal acquisition has long been known to offer advantages for processing signals further. The processing capabilities of mobile devices had not previously been able to handle the required computation to handle these previous streams of information. But current processing capabilities are such that the extra workload introduced by the addition of mutiple sensors on a mobile device are not over-burdensome. How these extra data streams can best be handled is still an open question. The present work deals with the examination of one type of spatial processing technique, known as beamforming. A microphone array test platform is constructed and verified through a number of beamforming agorithms. Issues related to speech acquisition through microphones arrays are discussed. The algorithms used for verification are presented in detail and compared to one another.
327

Worst Case Execution time Analysis Support for the ARM Processor Using GCC

Yen, Cheng-Yu 09 August 2010 (has links)
This thesis presents a tool for obtaining worst-case execution time (WCET) guarantees for ARM processors. This tool is an interface between ARM¡¦s GCC compiler and the SWEET WCET analyzer. SWEET is an open-source static analyzer that derives a guaranteed upper bound on the WCET of a program. The WCET of a program is an important metric in real-time systems. The task scheduler must decide how much time to allot for each process; if the allotted time exceeds the WCET, the process can be guaranteed to always finish in time. Although the WCET value is therefore useful, it is difficult to find. But, for the purpose of guaranteeing that a process finishes on time, an upper bound on the WCET suffices. Static program analysis has been proposed as a method to derive such an upper-bound on the WCET, by means of conservatively approximating the runtime of the individual parts of a complete program. SWEET is one such static analyzer. Our tool works inside of ARM-GCC, extracting all of the information that SWEET needs about the program¡¦s behavior. Our tool then packages the information into the SWEET¡¦s ALF format. The tool has been tested and works correctly for every input source that we have tested (including all 34 benchmarks from the WCET BENCHMARK SUITE[1]). This work was funded by Taiwan¡¦s National Science Council, grant NSC 97-2218-E-110-003
328

Microbial bioremediation and monitoring of a TCE-contaminated site

Li, Kuan-hsun 11 July 2011 (has links)
The goal of this study was to use molecular biology techniques to access and monitor the efficacy of bioremediation on a trichloroethene (TCE) polluted site. We added emulsified hydrogen releasing materials to stimulate onsite microbial growth and the biodegradation of TCE. This process was known as enhanced bioremediation. In this study, there were two bioremediation sites had been treated anaerobically. Groundwater samples were taken periodically for microbial analysis. Denaturing gradient gel electrophoresis (DGGE) was used to evaluate the variations in microbial community structures during the in situ groundwater remediation. The DGGE DNA bandings were sequenced to determine the 16S rRNA gene sequences and identify the dominate bacterial species. In addition, we used Dehalococcoides spp. 16S rRNA genes as the targets to do real-time PCR. Results show that the emulsified hydrogen releasing materials could enhance anaerobic reductive dechlorination. After addition of emulsified hydrogen releasing materials, we found that the volatile organic compounds concentrations (i.e., TCE, 1, 1-DCE and VC) were decreased. In microbial analysis, the diversities of the microbial community were increased after nutrient supplement. According to the DNA sequencing results, there were 31 bacterial species had been found that related to TCE degradation (i.e., Acidovorax sp., Burkholderiales, Pseudomonas sp., £]-proteobacterium, Comamonadaceae, Iron-reducing bacterium, Hydrogenophilaceae, Clostridium sp., Geobacter sp., Rhodoferax ferrireducens, Dehalospirillum multivorans and Dehalococcoides spp.). Dehalococcoides spp. can be used as a biomarker to evaluate the efficacy of anaerobic bioremediation on a TCE contaminated site. Therefore, we quantified Dehalococcoides populations to explain the capacity of bioremediation after addition of emulsified hydrogen releasing materials to groundwater. Results reveal that Dehalococcoides cell numbers of site A were 4.47¡Ñ103-8.26¡Ñ104 CFU/liter, site B were 4.60¡Ñ102-9.31¡Ñ107 CFU/liter. This data indicated that the addition of emulsified substrate would increase the growth of total Dehalococcoides population under anaerobic conditions. Overall, results from this study demonstrated that the microbial analysis and quantities of Dehalococcoides at different time points can provide useful information to proceed with bioremediation methods.
329

Microcosm batch study of the degradation of 1,2-DCA-contaminated soil

Huang, Chih-wei 23 July 2012 (has links)
1,2-dichloroethane (1,2-DCA) is a popular industrial chlorinated organic chemical. Because 1,2-DCA is a dense non-aqueous phase liquid and easily accumulated in deep soil and water, it is difficult to be removed from the contaminated sites. In this study, aerobic and anaerobic microcosm batch experiments were performed to evaluate the feasibility of biodegradation of 1,2-DCA by adding different growth substrates. The aerobic microcosm results show that approximately 90% of 1,2-DCA removal was observed in the natural degradation group (A1) and the aerobic sludge addition group (A3) after 7 days of incubation. Up to 95% of 1,2-DCA removal could be observed in the substrate supplement group in after 14 days of incubation. In the anaerobic microcosm studies, 50% of 1,2-DCA removal could be obtained in all groups after 10 days except for the natural degradation group (B1). Moreover, the degradation efficiency for the anaerobic sludge group (B3) reached 80% of 1,2-DCA removal in 5 days. The DGGE profiles show that the microbial diversity varied with time and the sugar supplement groups (A2, B2) exhibited the most microbial diversity. Bacterial clones results revealed that the 1,2-DCA biodegradable microbial strains were presented in the microcosms, such as Klebsiella, Pseudomonas, Rhodoferax and Xanthobactor. The real-time PCR results indicated that the Dehalococcoides spp. was the major bacterium that was responsible for the degradation of 1,2-DCA in the anaerobic substrate supplement group (B2). Desulfitobacterium spp. could be the dominant 1,2-DCA degrading bacterium for the aerobic substrate supplement group (A2) and all of the anaerobic groups (B1, B2, B3, B4).
330

The Implementation of Real-time Transmission with Partial Reliability in Wide Area Networks

Lin, Pin-hsin 12 September 2012 (has links)
Due to the rapid development of the Internet and the fast expansion of the bandwidth, the requirement of the real-time service for the Internet is necessary. In this way, the problem of the real-time service for the Internet becomes an important issue. Most of the applications still use TCP as the protocol, but due to the reliable property of TCP, TCP can¡¦t fit the requirement of the real-time transfer. So, we need to implement a protocol which we can use on the real-time transfer service. According to the requirement, we find an open source application layer protocol ¡V UDT (UDP-based Data Transfer). We can implement the application of real-time transfer by using the partial reliable messaging property of the protocol. In addition, user can adjust the parameters or settings of the protocol to make their application get into better performance by using the composable property of the protocol. In our research, we¡¦ll compare with RTP (Real-time Transport Protocol) and UDT, and also explain the reason why we don¡¦t choose RTP in our research. The assumption environment of our research is financial real-time service, and the protocol of such applications is TCP. In this way, we¡¦ll analyze and compare the result of the tests between TCP and UDT. We¡¦ll also adjust the parameters of the protocol to test the performance of the UDT under the environment of the real-time transfer, such as data lose rate, etc.. These results can supply the reference for the users when using UDT as their protocol to implement their real-time applications.

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