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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.
451

Theoretical and experimental investigation of the stability of the axisymmetric wellbore

Santarelli, Frederic Joseph January 1987 (has links)
No description available.
452

COMPASS - A Guide For Selection Of Compression Strategies For Embedded Processors

Menon, Sreejith K 07 1900 (has links) (PDF)
No description available.
453

Video Compression Through Spatial Frequency Based Motion Estimation And Compensation

Menezes, Vinod 02 1900 (has links) (PDF)
No description available.
454

The development of test procedures for controlling the quality of the manufacture of engineered compression stockings

Moghaddassian Shahidi, Arash January 2010 (has links)
A new technology platform known as 'Scan2Knit' was invented in the William Lee innovation Centre of the University of Manchester to engineer and manufacture compression stockings for the treatment of venous disease in a Welcome Trust funded research project. The intellectual property of the above technology has been licensed for commercial exploitation by the University.The graduated pressure profile that is necessary for the treatment of venous ulcers is generated with the engineered compression stocking, and will depend on the stitch length of the knitted fabric structure and an empirical pressure profile database. The 'Scan2Knit' technology was developed to produce an engineered compression stocking on a 18 gauge Stoll CMS computerised flat-bed knitting machine utilising a microprocessor controlled precision positive yarn delivery system to guarantee the delivery of a predetermined stitch length to the knitting needles. However, the licensee of the technology has decided to manufacture engineered compressions stockings by using 14 gauge Stoll CMS flat-bed knitting machines instead of gauge 18 machines due to commercial advantages. Therefore, the main aim of this work is to investigate the transfer of 'Scan2Knit' technology on to a coarse gauge manufacturing platform to produce engineered compression stockings. The investigation focuses on two vital requirements of 'Scan2Knit' technology; the analysis of the performance of the precision positive yarn delivery system on the new production platform and the evaluation of the functionality of the knitted structure produced with it. The objectives of the research are to develop test procedures for the evaluation of the three dimensional pressure characteristic of compression stockings manufactured on the new production platform, and the performance of the precision yarn delivery system. To produce the engineered compression stockings with the 'Scan2Knit' technology, it is essential to determine the interface pressure that the knitted structure would impart on a particular radius of curvature at a predetermined strain percentage which is attained with an empirical database. Hence, a key objective of this study is to develop a methodology, which is efficient and user friendly, for the generation of the empirical pressure profile database required to engineer the interface pressure profile of a compression stocking.It is envisioned that the manufacturer of the engineered compression stockings would benefit by the knowledge generated within this research, and develop their own quality assurance procedures to guarantee that the compression stockings are produced to deliver the graduated pressure profile prescribed by the clinician for the treatment of venous ulcers.
455

New Frameworks for Secure Image Communication in the Internet of Things (IoT)

Albalawi, Umar Abdalah S 08 1900 (has links)
The continuous expansion of technology, broadband connectivity and the wide range of new devices in the IoT cause serious concerns regarding privacy and security. In addition, in the IoT a key challenge is the storage and management of massive data streams. For example, there is always the demand for acceptable size with the highest quality possible for images to meet the rapidly increasing number of multimedia applications. The effort in this dissertation contributes to the resolution of concerns related to the security and compression functions in image communications in the Internet of Thing (IoT), due to the fast of evolution of IoT. This dissertation proposes frameworks for a secure digital camera in the IoT. The objectives of this dissertation are twofold. On the one hand, the proposed framework architecture offers a double-layer of protection: encryption and watermarking that will address all issues related to security, privacy, and digital rights management (DRM) by applying a hardware architecture of the state-of-the-art image compression technique Better Portable Graphics (BPG), which achieves high compression ratio with small size. On the other hand, the proposed framework of SBPG is integrated with the Digital Camera. Thus, the proposed framework of SBPG integrated with SDC is suitable for high performance imaging in the IoT, such as Intelligent Traffic Surveillance (ITS) and Telemedicine. Due to power consumption, which has become a major concern in any portable application, a low-power design of SBPG is proposed to achieve an energy- efficient SBPG design. As the visual quality of the watermarked and compressed images improves with larger values of PSNR, the results show that the proposed SBPG substantially increases the quality of the watermarked compressed images. Higher value of PSNR also shows how robust the algorithm is to different types of attack. From the results obtained for the energy- efficient SBPG design, it can be observed that the power consumption is substantially reduced, up to 19%.
456

Better Selection of K-mers for Compression of DNA Sequences using Huffman Encoding

Agrahari, Manoj Kumar 01 September 2021 (has links)
The genome of an organism contains all hereditary information encoded in DNA.Genome databases are rapidly increasing. This increase in the amount of DNA data demands an increasing need to compress the DNA data in less space for faster transmission and research activities. General text compression algorithms don’t utilize the specific characteristics of a DNA sequence. There are various tools developed using different algorithms and approaches. Many of these tools include the implementation of Huffman encoding to incorporate the characteristics of DNA sequences. Huffman-based techniques center on the idea of selecting repeated sequences to form a skewed Huffman tree. The algorithm also lies around constructing multiple Huffman trees when encoding. These implementations have demonstrated an improvement in the compression ratios compared to the standard Huffman tree. This research suggests few improvements over one of these algorithms to select the repeat sequences to obtain better compression ratios.
457

Evaluation of ANSI compression in a bulk data file transfer system

Chaulklin, Douglas Gary 20 January 2010 (has links)
This report evaluates the use of a newly proposed American National Standard Institute (ANSI) standard for data compression in a bulk data transmission system. An overview of the transmission system, the current compression method, and the ANSI algorithm are presented. A dynamic systems model is used to analyze the benefits and impacts of various alternatives to addressing the needs of the system. A decision model is built to summarize the alternatives based on the perceived problem contexts. / Master of Engineering
458

Mechanical Properties of Polymer Modified Mortar

Palos, Artemio 08 1900 (has links)
The mechanical properties of the polymer-modified mortar are markedly improved over conventional cement mortar. We utilized recycled ABS in powder form and a polymer latex emulsion, polymer percentage ranges from 0 to 25 percent by polymer/cement ratio were investigated. The mechanical properties investigated were compression strength and adhesion strength. Compression strength effects did not have an impact on adhesion strength. Adhesion strength was calculated with pullout testing apparatus designed by the author. Results indicate that recycled ABS had a lower adhesive strength than the acrylic latex emulsion and the base mortar, but did increase in adhesive strength when mixed with maleic-anhydride. The adhesive strength was investigated for a Fiber Reinforced Polymer (FRP) made of an "E" glass fiber that is a continuous strand roving oriented and pre-tensioned longitudinally in an isopthalic polyester matrix material. The FRP rebar was compared to standard steel rebars, and found that the standard steel corrugated rebar had a higher adhesive strength, due to mechanical interlocking. This was clarified by measurements using a smooth steel rebar. Characterization of the polymer-modified mortar was conducted by pore analysis and scanning electron microscopy. Scanning Electron Microscopy was implemented to view the polymer particles, the cement fibrils formed by the hydration, and to prove Ohama's theory of network structure.
459

Wavelet Image Compressor - Minimage

Gu, Hao, Hong, Don, Barrett, Martin 01 January 2003 (has links)
Nowadays, still images are used everywhere in the digital world. The shortages of storage capacity and transmission bandwidth make efficient compression solutions essential. A revolutionary mathematics tool, wavelet transform, has already shown its power in image processing. Minimage, the major topic of this paper, is an application that compresses still images by wavelets. Minimage is used to compress grayscale images and true color images. It implements the wavelet transform to code standard BMP image files to LET wavelet image files, which is defined in Minimage. The code is written in C++ on the Microsoft Windows NT platform. This paper illustrates the design and implementation details in MinImage according to the image compression stages. First, the preprocessor generates the wavelet transform blocks. Second, the basic wavelet decomposition is applied to transform the image data to the wavelet coefficients. The discrete wavelet transforms are the kernel component of MinImage and are discussed in detail. The different wavelet transforms can be plugged in to extend the functionality of MinImage. The third step is the quantization. The standard scalar quantization algorithm and the optimized quantization algorithm, as well as the dequantization, are described. The last part of MinImage is the entropy-coding schema. The reordering of the coefficients based on the Peano Curve and the different entropy coding methods are discussed. This paper also gives the specification of the wavelet compression parameters adjusted by the end user. The interface, parameter specification, and analysis of MinImage are shown in the final appendix.
460

Mechanical Properties of Porcine Muscle in Compression and Tension with Microstructural Analysis

Pietsch, Renee Brook 11 August 2012 (has links)
A need exists for a more robust method of evaluating musculoskeletal injuries resulting from impact conditions, particularly blasts. Computational modeling is a promising method of achieving this goal. The accuracy of a model depends on high quality mechanical properties for each component. This study examined the mechanical properties of porcine muscle along with structure property relationships. Fresh muscle was tested in compression and tension at strain rates of 0.1 s-1, 0.01 s-1, and 0.001 s-1. Viscoelastic properties were observed including strain rate dependency, stress state dependency, anisotropy, relaxation, and hysteresis. Image analysis was conducted in compression on controls, 30% strain, and 50% strain, relating stress-strain data with structural changes. The effect of rigor was also seen in the tensile response of muscle. Thawed tissue was examined to investigate the effects of freezing. It was found that freezing did not significantly change the mechanical properties, but substantial microstructural changes did occur.

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