A Study of trellis coded quantization for image compression

Trellis coded quantization has recently evolved as a powerful quantization technique in the world of lossy image compression. The aim of this thesis is to investigate the potential of trellis coded quantization in conjunction with two of the most popular image transforms today; the discrete cosine transform and the discrete wavelet trans form. Trellis coded quantization is compared with traditional scalar quantization. The 4-state and the 8-state trellis coded quantizers are compared in an attempt to come up with a quantifiable difference in their performances. The use of pdf-optimized quantizers for trellis coded quantization is also studied. Results for the simulations performed on two gray-scale images at an uncoded bit rate of 0.48 bits/pixel are presented by way of reconstructed images and the respective peak signal-to-noise ratios. It is evident from the results obtained that trellis coded quantization outperforms scalar quantization in both the discrete cosine transform and the discrete wavelet transform domains. The reconstructed images suggest that there does not seem to be any considerable gain in going from a 4-state to a 8-state trellis coded quantizer. Results also suggest that considerable gain can be had by employing pdf-optimized quantizers for trellis coded quantization instead of uniform quantizers

Analytical approach to the transition to thermal hopping in the thin- and thick-wall approximations

The nature of the transition from the quantum tunneling regime at low temperatures to the thermal hopping regime at high temperatures is investigated analytically in scalar field theory. An analytical bounce solution is presented, which reproduces the action in the thin-wall as well as thick-wall limits. The transition is first order for the case of a thin wall while for the thick wall case it is second order.Comment: Latex file, 22 pages, 4 Postscript figure

Essential Mechanics - Statics and Strength of Materials with MATLAB and Octave

Essential Mechanics - Statics and Strength of Materials with MATLAB and Octave combines two core engineering science courses - “Statics” and “Strength of Materials” - in mechanical, civil, and aerospace engineering. It weaves together various essential topics from Statics and Strength of Materials to allow discussing structural design from the very beginning. The traditional content of these courses are reordered to make it convenient to cover rigid body equilibrium and extend it to deformable body mechanics.The e-book covers the most useful topics from both courses with computational support through MATLAB/Octave. The traditional approach for engineering content is emphasized and is rigorously supported through graphics and analysis. Prior knowledge of MATLAB is not necessary. Instructions for its use in context is provided and explained. It takes advantage of the numerical, symbolic, and graphical capability of MATLAB for effective problem solving. This computational ability provides a natural procedure for What if? exploration that is important for design. The book also emphasizes graphics to understand, learn, and explore design. The idea for this book, the organization, and the flow of content is original and new. The integration of computation, and the marriage of analytical and computational skills is a new valuable experience provided by this e-book. Most importantly the book is very interactive with respect to the code as it appears along with the analysis.https://scholarworks.rit.edu/ritbooks/1002/thumbnail.jp

Protocol design, implementation and integration for the protection of sensor data confidentiality and integrity

Wireless sensor networks are data centric because in many applications, sensor nodes are required to generate data, collect data, storage data and process data queries. Meanwhile, wireless sensor networks are vulnerable to security attacks because they are deployed in unattended (often hostile) environments and do not have tamper resistant hardware. Therefore, secure and efficient data management schemes are necessary to sensor networks. In this thesis work, we study how to secure a representative type of sensor data management approach called data centric storage based (DCS) schemes, with focus on protecting data confidentiality and integrity.;Considerable efforts have been made for securing DCS, however, existing work has the limitations of (i) not considering user node compromise, (ii) lack of studies on real system implementation and detailed experiments, and (iii) lack of studies on integrating security schemes to defend against multiple attacks simultaneously. To overcome these limitations, we have conducted the following research: Firstly, we have designed a new data confidentiality protocol called DKVP (data and key vulnerability protection) scheme to protect sensor data confidentiality in presence of user node compromise. Secondly, we have implemented three polynomial-based sensor data confidentiality and integrity protection schemes, namely, the adaptive polynomial-based scheme for secure data storage and query (APB), the message authentication function based schemes for data integrity (MAF), and the DKVP scheme, on top of TinyOS/Mote platform. Thirdly, we have developed a prototype system that consists of (i) integrated data confidentiality and integrity protection modules (i.e., the APB, MAF and DKVP schemes), (ii) effective and friendly interfaces to application developers to facilitate inclusion of security features into application programs, and (iii) example programs to demonstrate the integration suite developed by us.;Extensive experiments have been conducted to study the feasibility and performance of the above designs and implementations. The results show that, if system parameters are properly chosen, desired security level can be achieved which is cost affordable by the current generation of sensor nodes such as MICA motes. In particular, our study shows that running the three integrated protocols together consumes only 27 msec of processing time and 60% of CPU usage

Numerical Investigation of Rotating Lid-driven Cubical Cavity Flow

The present work numerically investigates the flow field in a cubical cavity driven by a lid rotating about an axis passing through its geometric center. Behaviour of core flow and secondary vortical structures are presented. Grid-free critical Reynolds number at which flow turns oscillatory is estimated to be 1606. This differs significantly from the linear lid-driven cubical cavity as well as circular lid-driven cylindrical cavity flows which have been reported to attain unsteadiness at higher Reynolds numbers. A stationary vortex bubble similar to rotating lid-driven cylindrical cavity flow has been observed to be present in the flow

Benchmarking holiday experience: the case of senior tourists

Purpose: The purpose of this paper is to determine and benchmark the senior tourists’ preferences by considering the importance attached by them and their perception with respect to internal tourism attributes (i.e. package tour characteristics) and external tourism attributes (i.e. destination features). Design/methodology/approach: The present study makes use of importance-performance analysis and employs paired sample t-test for this purpose. Findings: The senior tourists evaluated the package tour attributes to be more important and better than destination characteristics. They also perceived that the service providers have to pay immediate attention to improve the quality of restaurants and meals and hotels. Research limitations/implications: Data are collected only from inbound senior tourists in Poland. In future, research may be conducted with a more representative sample. Practical implications: The senior tourists want to explore the local cuisine and then have food choices from their culture as well. “Tour escort” is one of the most essential characteristic of a package tour and it could serve as a factor of differentiation. Hence, the tourist service providers have to pay attention to these factors. Originality/value: The paper takes into account the internal tour attributes and destination attributes to evaluate senior tourists’ holiday experienceinfo:eu-repo/semantics/submittedVersio