Compression Resilience Research Articles

A family of efficient and channel error resilient wavelet/subband image coders

We present a new wavelet/subband framework that allows the efficient and effective quantization/coding of subband coefficients in both noiseless and noisy channel environments. Two different models, one based on a zero-tree structure and another based on a quadtree and context-based modeling structure, are introduced for coding the locations of significant subband coefficients. Then, several multistage residual lattice vector quantizers are proposed for the quantization of such coefficients. The proposed framework features relatively simple modeling and quantization/coding structures that produce a bit stream containing two distinct bit sequences, which can then be protected differently according to their importance and channel noise sensitivity levels. The resulting wavelet/subband image coding algorithms provide good tradeoffs between compression performance and resilience to channel errors, In fact, experimental results indicate that for both noiseless and noisy channels, the resulting coders outperform most of the source-channel coders reported in the literature. More importantly, our coders are substantially more robust than all previously reported source-channel coders with respect to varying channel error conditions. This is a desired feature in low-bandwidth wireless applications.

Aggrecan: A Target Molecule of Autoimmune Reactions.

Aggrecan in cartilage forms aggregates with hyaluronan and link protein, embedded in a collagen network. It accounts for the compressive stiffness and resilience of the hyaline cartilage. Many forms of inflammatory arthritis were shown to be accompanied with aggrecan degradation and loss from the cartilage. The loss of this major component of cartilage renders the tissue more vulnerable when exposed to abrasive forces. Therefore, aggrecan degradation may significantly contribute to cartilage destruction in arthritis. Furthermore, fragments of degraded aggrecan are released during joint inflammation. Thus, molecules of an avascular, immune-privileged tissue (hyaline cartilage) may become accessible to the cells of the immune system. Similarly, there is a "leakage" of aggrecan fragments from cartilage during aging and after joint injury, which may also lead to autosensibilisation. Autoimmune reactivity to aggrecan can be detected in human joint diseases, as well as in animal models of arthritis. The epitopes involved in these processes are currently being identified. Recent data from work with mice suggest a strong immune response focused to the N-terminal G1 domain of aggrecan that leads to arthritis and spondylitis.

Low Stress Mechanical Behavior of Cotton / Polyester Yarns and Fabrics in Relation to Fiber Distribution Within the Yarn

Low stress mechanical properties of cotton /polyester yams representing random fiber disposition and core-sheath construction are compared to determine the influence of fiber distribution on yam properties. The yams are converted into plain weave fabrics under identical conditions, and fabric properties are compared to understand how yam properties translate into fabric properties. The core-sheath yarn (polyester core/cotton-covered yam) shows lower values for bending rigidity, bending hysteresis, compressive resilience, and tensile elongation. The same yarn also shows higher values for compressive softness and tensile modulus. The lower tensile elongation and higher tensile modulus of the core-sheath yam is reflected in the lower elongation and higher modulus of the corresponding fabric. However, bending and compression properties of the core-sheath yarn are inversely related to bending and compression properties of the corresponding fabric. Results show that yarn bulk and compression properties exert a greater influence on the bending behavior of a plain weave fabric than yarn bending properties. Results also reveal that a closely woven plain weave fabric made from a less resilient and easily compressible yarn can prove to be more resilient to compression and more difficult to compress in the fabric stage.

Compressional Behaviour of Double-rove Yarns

Little information is available in the literature about double-rove spun yarn's low-stress mechanical properties. An experimental investigation has been made in a short-staple spinning system to study the effect of strand spacing, twist, and spindle speed on a double-rove yarn's compressive resilience, and compressibility at low-stress levels. The response-surface equations developed from the experimental results, have been used to explain the compressional behaviour of the yarn studied.

Applying Factor Analysis to the Hand of Terry Fabrics

When the hand of terry fabrics is designed, it is important that interrelations between the sensory value of the hand and various objective tests on terry fabrics, whose pile design factors are changed diversely, are investigated. When two factors of the pile design (a pile ratio and an effective fiber length of a pile warp yarn) are changed, the sense of touch becomes better as energy loss ratio increases and gets worse as compressive resilience, modulus, and recovery ratio increase. When changing two factors of the pile design (a twist number of a pile warp yam and a yarn count of pile warp), the sense of touch becomes better as compressive energy, frictional coefficient, and thickness increase, and gets worse as compressive resilience increases.

Engineering Properties of Viton® Fluoroelasromer

VITON® fluoroelastomers, are used in applications requiring resistance to heat aging at temperatures to 650°F., and resistance to fluids and chemicals to 450°F. Characteristic properties of vulcanizates are discussed and include compression set, permeability, resilience, and environmental resistance. Representative case histories illustrating how an elastomer with exceptional heat and fluid resistance was used to solve particularly difficult problems shows the uniqueness of this elastomer.

ON THE BULK COMPESSIONAL CHARACTERISTICS OF FIBER MASS

The influence of operating conditions on the experimental results were investigated and the standard test conditions were established.After the compression experiments on several fibers the possible evaluations were discussed, and it is proposed to characterize the bulkiness of fibers by the compression energy, resilience and fatigue ratio given as the ratio of the energy of deformation in the first and 2 nd cycles.Compressional index expressed in the forms of product of compression energy, resilience and fatigue ratio are defined as the values which collectively evaluate the bulk compression characteristics of fibers.The evaluation by compressional index shows a good agreement with handling test results.

ON THE BULK COMPRESSIONAL CHARACTERISTICS OF FIBER MASS

The influence of operating conditions on the experimental results were investigated and the standard test conditions were established.After the compression experiments on several fibers the possible evaluations were discussed, and it is proposed to characterize the bulkiness of fibers by the compression energy, resilience and fatigue ratio given as the ratio of the energy of deformation in the first and 2 nd cycles.Compressional index expressed in the forms of product of compression energy, resilience and fatigue ratio are defined as the values which collectively evaluate the bulk compression characteristics of fibers.The evaluation by compressional index shows a good agreement with handling test results.