关键词： Lot streaming   Hybrid flexible flowshop   Genetic algorithm   Parallel computing  

摘要： Lot streaming is the technique of splitting a given job into sublots to allow the overlapping of successive operations in multi-stage manufacturing systems thereby reducing production makespan. Several research articles appeared in literature to solve this problem and most of these studies are limited to pure flowshop environments where there is only a single machine in each stage. On the other hand, because of the applicability of hybrid flowshops in different manufacturing settings, the scheduling of these types of shops is also extensively studied by several authors. However, the issue of lot streaming in hybrid flowshop environment is not well studied. In this paper, we aim to contribute in bridging the gap between the research efforts in flowshop lot streaming and hybrid flowshop scheduling. We propose a mathematical model and a genetic algorithm for the lot streaming problem of several jobs in multi-stage flowshops where at each stage there are unrelated parallel machines. The jobs may skip some of the stages, and therefore, the considered system is a complex generalized flowshop. The proposed genetic algorithm is executed on both sequential and parallel computing platforms. Numerical examples showed that the parallel implementation greatly improved the computational performance of the developed heuristic.

关键词： Combinatories on words   partial words   pattern avoidance   subword complexity   algorithms  

摘要： Algorithmic combinatorics on partial words, or sequences of symbols over a finite alphabet that may have some do-not-know symbols or holes, has been developing in the past few years. Applications can be found;for instance, in molecular biology for the sequencing and analysis of DNA, in bio-inspired computing where partial words have been considered for identifying good encodings for DNA computations, and in data compression. In this paper, we focus on two areas of algorithmic combinatorics on partial words, namely, pattern avoidance and subword complexity. We discuss recent contributions as well as a number of open problems. In relation to pattern avoidance, we classify all binary patterns with respect to partial word avoidability, we classify all unary patterns with respect to hole sparsity, and we discuss avoiding abelian powers in partial words. In relation to subword complexity, we generate and count minimal Sturmian partial words, we construct de Bruijn partial words, and we construct partial words with subword complexities not achievable by full words (those without holes).

关键词： Dense linear algebra libraries   Graphics processors   Runtime systems   High performance computing  

摘要： Parallel accelerators are playing an increasingly important role in scientific computing. However, it is perceived that their weakness nowadays is their reduced "programmability" in comparison with traditional general-purpose CPUs. For the domain of dense linear algebra, we demonstrate that this is not necessarily the case. We show how the libflame library carefully layers routines and abstracts details related to storage and computation, so that extending it to take advantage of multiple accelerators is achievable without introducing platform specific complexity into the library code base. We focus on the experience of the library developer as he develops a library routine for a new operation, reduction of a generalized Hermitian positive definite eigenvalue problem to a standard Hermitian form, and configures the library to target a multi-GPU platform. It becomes obvious that the library developer does not need to know about the parallelization or the details of the multi-accelerator platform. Excellent performance on a system with four NVIDIA Tesla C2050 GPUs is reported. This makes libflame the first library to be released that incorporates multi-GPU functionality for dense matrix computations, setting a new standard for performance. (C) 2011 Elsevier Inc. All rights reserved.

关键词： Host mobility   network mobility   quality of service   delay-sensitive algorithm   mobile networks  

摘要： The mobile networks play a vital role in the information and communication technology. There are two kinds of mobility supported by mobile networks such as host mobility and network mobility. The enhancement of Quality of Service (QoS) in NEtwork MObility (NEMO) environment is more complex than host mobility environment. One of the complexities in NEMO environment is routing of packets. The routing algorithms play a significant role in enhancing QoS. This necessitates looking into the weaknesses of existing routing algorithms. Based on the weaknesses, we have already proposed a Delay-Sensitive Routing for NEMO (DSRNEMO) to enhance the QoS in NEMO environment with respect to delay parameter. The objectives of this paper are to derive a mathematical model for DSRNEMO and to simulate the operations of DSRNEMO. The outcome of the mathematical model and simulation results show that the DSRNEMO gives better results than the existing algorithm, NEMO. Ultimately, this paper contributes to enhance the QoS in mobile networks.

关键词： LLE data   Ternary mixture   Genetic algorithm   GMDH-type NN  

摘要： A GMDH type-neural network was used to predict liquid phase equilibrium data for the (water + ethanol + trans-decalin) ternary system in the temperature range of 300.2-315.2K. In order to accomplish modeling, the experimental data were divided into train and test sections. The data set was divided into two parts: 70% were used as data for "training" and 30% were used as a test set. The predicted values were compared with those of experimental values in order to evaluate the performance of the GMDH neural network method. The results obtained by using GMDH type neural network are in excellent agreement with the experimental results. (C) 2011 Elsevier Inc. All rights reserved.

关键词： fast algorithm   discrete cosine transform   Galois's theory  

摘要： An algebraic method for synthesizing fast algorithms of the discrete cosine transform (DCT) of arbitrary size is proposed. The method is based on the polynomial algebra F [x]/p(x) associated with the DCT. The fast DCT algorithm comes as a result of the step-by-step decomposition of this algebra. In turn, the decomposition requires step-by-step factorization of the polynomial p(x). This problem is solved using Galois's theory, which allows finding all the subfields of the splitting field of the polynomial p(x) where p(x) can be factorized.

关键词： 车牌定位   水平投影   形态学   边缘检测   迭代膨胀法  

摘要： 车牌定位是车牌识别系统中的关键技术之一,车牌定位的质量直接影响着后续字符识别的结果。本文提出了一种结合投影法和形态学的车牌定位算法,首先对图像进行预处理,接着利用水平投影算法确定车牌的上下边界,然后利用形态学方法迭代确定车牌的左右边界,最后进行精定位。实验表明,该方法具有较高的定位精度。

关键词： 复杂注水井   自动组配   数学算法   计算机算法  

摘要： 复杂注水井管柱通常由三个以上的封隔器和配水器组成,由于编写施工方案时无法预知现场油管实际情况。施工方案只能提出井下工具的最终深度,注水井管柱的组配工作由现场技术员完成。受油管长度、油层厚度、测量误差等因素影响,很容易因计算错误造成返工,给现场技术人员造成极大心理负担。本文主要介绍了复杂水井管柱组配数学实质、数学算法、计算机算法等三个方面。

关键词： 算法   学习算法的意义   构造性数学   算法的教学  

摘要： 随着现代信息技术的迅猛发展,算法已融入生活的众多方面,扮演着重要的角色。在高中数学教科书中也将算法作为一个独立的章节在学习,算法的思想和初步知识也正在成为普通公民的常识。主要论述了什么是算法以及学生学习算法的意义。

关键词： 科学技术   数学方法   国际数学家大会   算法   模型   论文集  

摘要： 本书是2010年国际数学家大会（印度）的一个卫星会议——“科学和技术中的数学”的会议论文集。