The article discusses various reports published within the issue, including one on a dual-thread speculation system and another on a parallel version of the Tricluster algorithm.
The article discusses various reports published within the issue, including one on a dual-thread speculation system and another on a parallel version of the Tricluster algorithm.
In this paper we give a computer proof of a new polynomial identity, which extends a recent result of Alladi and the first author. In addition, we provide computer proofs for new finite analogs of Jacobi and Euler for...
详细信息
In this paper we give a computer proof of a new polynomial identity, which extends a recent result of Alladi and the first author. In addition, we provide computer proofs for new finite analogs of Jacobi and Euler formulas. All computer proofs are done with the aid of the new computer algebra package qMultiSum developed by the second author. qMultiSum implements an algorithmic refinement of Wilf and Zeilberger's multi-q-extension of Sister Celine's technique utilizing additional ideas of Verbacten and Wegschaider. (C) 2002 Elsevier Science (USA).
A primary goal of quantum computer science is to find an explanation for the fact that quantum computers are more powerful than classical computers. In this paper I argue that to answer this question is to compare alg...
详细信息
A primary goal of quantum computer science is to find an explanation for the fact that quantum computers are more powerful than classical computers. In this paper I argue that to answer this question is to compare algorithmic processes of various kinds and to describe the possibility spaces associated with these processes. By doing this, we explain how it is possible for one process to outperform its rival. Further, in this and similar examples little is gained in subsequently asking a how-actually question. Once one has explained how-possibly, there is little left to do.
Presents a general overview of the various types of computer-based algorithms which can solve the resource allocation problem in warehouses. Comparison of heuristic algorithms with exact optimization models; Features ...
详细信息
Presents a general overview of the various types of computer-based algorithms which can solve the resource allocation problem in warehouses. Comparison of heuristic algorithms with exact optimization models; Features and applications of the various models; Future trends in developing computer-based algorithms.
Conducting polypyrrole/polyaniline colloidal composites have been prepared by deposition of the solution mixture of polypyrrole and polyaniline at negative potentials. Different substrates were dipped in the solution ...
详细信息
Conducting polypyrrole/polyaniline colloidal composites have been prepared by deposition of the solution mixture of polypyrrole and polyaniline at negative potentials. Different substrates were dipped in the solution containing the mixture together with acrylic latex and after drying the adhesive strength and electroactivity of the paint were studied. Several colloidal composite based coatings were investigated. At last a computer facilitated with powerful artificial neural network based algorithms classified the paints.
Atrial fibrillation (AF) is a common cardiac arrhythmia, but its mechanisms are incompletely understood. The identification of phase singularities (PSs) has been used to define spiral waves involved in maintaining the...
详细信息
Atrial fibrillation (AF) is a common cardiac arrhythmia, but its mechanisms are incompletely understood. The identification of phase singularities (PSs) has been used to define spiral waves involved in maintaining the arrhythmia, as well as daughter wavelets. In the past, PSs have often been identified manually. Automated PS detection algorithms have been described previously, but when we attempted to apply a previously developed algorithm we experienced problems with false positives that made the results difficult to use directly. We therefore developed a tool for PS identification that uses multiple strategies incorporating both image analysis and mathematical convolution for automated detection with optimized sensitivity and specificity, followed by manual verification. The tool was then applied to analyze PS behavior in simulations of AF maintained in the presence of spatially distributed acetylcholine effects in cell grids of varying size. These analyses indicated that in almost all cases, a single PS lasted throughout the simulation, corresponding to the central-core tip of a single spiral wave that maintained AF. The sustained PS always localized to an area of low acetylcholine concentration. When the grid became very small and no area of low acetylcholine concentration was surrounded by zones of higher concentration, AF could not be sustained. The behavior of PSs and the mechanisms of AF were qualitatively constant over an 11.1-fold range of atrial grid size, suggesting that the classical emphasis on tissue size as a primary determinant of fibrillatory behavior may be overstated. (C) 2002 American Institute of Physics.
A new algorithm is described for the simulation of the organization processes that lead from an isotropic liquid to a crystal structure. The algorithm is based on a hybrid, pseudo-Monte Carlo technique that lets a mol...
详细信息
A new algorithm is described for the simulation of the organization processes that lead from an isotropic liquid to a crystal structure. The algorithm is based on a hybrid, pseudo-Monte Carlo technique that lets a molecular assembly evolve under Metropolis conditions subject to forcing the decrease of asymmetry parameters that quantify the deviation from intermolecular alignment. This procedure was applied to the simulation of the liquid-solid transformation in n-hexane. Starting from liquid n-hexane with a significant population of gauche molecular conformations, a crystalline molecular assembly with parallel all-trans aliphatic chains is generated. This structure is very similar to the real crystal structure, except for a small difference in molecular orientation within layers. The process apparently involves an activation energy of a few kJ mol(-1) and a very minor volume activation that could be associated with density fluctuations due to the need for extra space as long molecules undergo a large conformational rearrangement. Although some detailed quantitative aspects of the simulation may be open to discussion, this is one of the very few examples of individuation of a continuous all-atom trajectory linking the liquid and the solid state of a large polyatomic molecule. The results confirm the viability of the symmetry bias for the generation of new crystal structures, and provide valuable working hypotheses on the mechanism of crystallization.
Background Artificial intelligence (AI) is increasingly being used in medical practice. Especially in the image-based diagnosis of skin cancer, AI shows great potential. However, there is a significant discrepancy bet...
详细信息
Background Artificial intelligence (AI) is increasingly being used in medical practice. Especially in the image-based diagnosis of skin cancer, AI shows great potential. However, there is a significant discrepancy between expectations and true relevance of AI in current dermatological practice. Objectives This article summarizes promising study results of skin cancer diagnosis by computer-based diagnostic systems and discusses their significance for daily practice. We hereby focus on the analysis of dermoscopic images of pigmented and unpigmented skin lesions. Materials and methods A selective literature search for recent relevant trials was conducted. The included studies used machine learning, and in particular "convolutional neural networks", which have been shown to be particularly effective for the classification of image data. Results and conclusions In numerous studies, computer algorithms were able to detect pigmented and nonpigmented neoplasms of the skin with high precision, comparable to that of dermatologists. The combination of the physician's assessment and AI showed the best results. computer-based diagnostic systems are widely accepted among patients and physicians. However, they are still not applicable in daily practice, since computer-based diagnostic systems have only been tested in an experimental environment. In addition, many digital diagnostic criteria that help AI to classify skin lesions remain unclear. This lack of transparency still needs to be addressed. Moreover, clinical studies on the use of AI-based assistance systems are needed in order to prove its applicability in daily dermatologic practice.
暂无评论