839,510 research outputs found
On an evaluation of transformation languages in a fully XML-driven framework for video content adaptation
Bitstream Structure Descriptions (BSDs) allow taking the complexity of transforming scalable bitstreams from the compressed domain to the semantic domain. These descriptions are an essential part of an XUL-driven video adaptation framework. The performance of a BSD transformation engine is very important in such an architecture. This paper evaluates the efficiency of XML-based transformation languages in our video adaptation framework. XSLT, STX, and a hybrid solution are compared to each other in terms of execution times, memory consumption, and user-friendliness. Our experiments show that STX is the preferred solution when speed and low-memory are important. The hybrid solution is competitive in terms of memory consumption and is more user-friendly than STX. Although XSLT is relative fast, its memory consumption is very high
Advances in martensitic transformations in Cu-based shape memory alloys achieved by in situ neutron and synchrotron X-ray diffraction methods
This article deals with the application of several X-ray and neutron diffraction methods to investigate the mechanics of a stress induced martensitic transformation in Cu-based shape memory alloy polycrystals. It puts experimental results obtained by two different research groups on different length scales into context with the mechanics of stress induced martensitic transformation in polycrystalline environment
Layered cellular automata for pseudorandom number generation
The proposed Layered Cellular Automata (L-LCA), which comprises of a main CA with L additional layers of memory registers, has simple local interconnections and high operating speed. The time-varying L-LCA transformation at each clock can be reduced to a single transformation in the set formed by the transformation matrix of a maximum length Cellular Automata (CA), and the entire transformation sequence for a single period can be obtained. The analysis for the period characteristics of state sequences is simplified by analyzing representative transformation sequences determined by the phase difference between the initial states for each layer. The L-LCA model can be extended by adding more layers of memory or through the use of a larger main CA based on widely available maximum length CA. Several L-LCA (L=1,2,3,4) with 10- to 48-bit main CA are subjected to the DIEHARD test suite and better results are obtained over other CA designs reported in the literature. The experiments are repeated using the well-known nonlinear functions and in place of the linear function used in the L-LCA. Linear complexity is significantly increased when or is used
A comparative study of immune system based genetic algorithms in dynamic environments
Copyright @ 2006 ACMDiversity and memory are two major mechanisms used in biology to keep the adaptability of organisms in the ever-changing environment in nature. These mechanisms can be integrated into genetic algorithms to enhance their performance for problem optimization in dynamic environments. This paper investigates several GAs inspired by the ideas of biological immune system and transformation schemes for dynamic optimization problems. An aligned transformation operator is proposed and combined to the immune system based genetic algorithm to deal with dynamic environments. Using a series of systematically constructed dynamic test problems, experiments are carried out to compare several immune system based genetic algorithms, including the proposed one, and two standard genetic algorithms enhanced with memory and random immigrants respectively. The experimental results validate the efficiency of the proposed aligned transformation and corresponding immune system based genetic algorithm in dynamic environments
Stress-Induced Phase Transformations in Shape-Memory Polycrystals
Shape-memory alloys undergo a solid-to-solid phase transformation involving a change of crystal structure. We examine model problems in the scalar setting motivated by the situation when this transformation is induced by the application of stress in a polycrystalline material made of numerous grains of the same crystalline solid with varying orientations. We show that the onset of transformation in a granular polycrystal with homogeneous elasticity is in fact predicted accurately by the so-called Sachs bound based on the ansatz of uniform stress. We also present a simple example where the onset of phase transformation is given by the Sachs bound, and the extent of phase transformation is given by the constant strain Taylor bound. Finally we discuss the stress–strain relations of the general problem using Milton–Serkov bounds
The role of phase interface energy in martensitic transformations: a lattice Monte-Carlo simulation
To study martensitic phase transformation we use a micromechanical model
based on statistical mechanics. Employing lattice Monte-Carlo simulations and
realistic material properties for shape-memory alloys (SMA), we investigate the
combined influence of the external stress, temperature, and interface energy
between the austenitic and martensitic phase on the transformation kinetics and
the effective material compliance. The one-dimensional model predicts well many
features of the martensitic transformation that are observed experimentally.
Particularly, we study the influence of the interface energy on the
transformation width and the effective compliance. In perspective, the obtained
results might be helpful for the design of new SMAs for more sensitive smart
structures and more efficient damping systems.Comment: 10 pages, 3 figures, 22 reference
Memory cost of quantum protocols
In this paper we consider the problem of minimizing the ancillary systems
required to realize an arbitrary strategy of a quantum protocol, with the
assistance of classical memory. For this purpose we introduce the notion of
memory cost of a strategy, which measures the resources required in terms of
ancillary dimension. We provide a condition for the cost to be equal to a given
value, and we use this result to evaluate the cost in some special cases. As an
example we show that any covariant protocol for the cloning of a unitary
transformation requires at most one ancillary qubit. We also prove that the
memory cost has to be determined globally, and cannot be calculated by
optimizing the resources independently at each step of the strategy.Comment: 9 page
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