函数优化异步并行演化算法

提出了一种新型、高效的函数优化异步并行演化算法,利用这个算法,在巨型并行计算机上解决了一些高难度的大型优化问题,其中包括一个超高维的非线性规划问题－BUMP问题。由于BUMP问题的强非线性和超我峰特性,目前还未见有超过50维的BUMP问题的结果发表。而在此不仅仅得到了从2维到50维迄今最好的解,而且一直计算到了1000000维,并得到了满意的结果。数值实验表明,新算法是鲁棒和高效的。     

超分布超并行智能处理的异步异质竞争行波方法

本文讨论超分布超并行智能处理的竞争行波方法中最一般的情形异步异质行波。同步均质和异步叠加方法都是本文方法的特例。提出了基于异步异质竞争行波的并行算法和性质。     

并行环境下的同步异步PSO算法

并行计算能够有效地缩减求解大规模问题的时间.文中在介绍了粒子群算法(Particle Swarm Optimization algo rithm)的基础上,对PSO算法的同步异步模型进行分析,给出了并行环境下的同步异步PSO算法.该并行算法在联想深腾1800大型汁算机上测试.实验证明PSO算法具有较高的并行性,并行算法明显提高了求解的速度.     

基于空间划分的细粒度并行演化算法

引入（μ＋１）选择策略，提出在群体形成的最小凸集中随机均匀地生成新个体的空间划分选择策略，并将其引入细粒度并行演化模型中，提出了应用于此模型的新算法。给出了并行动算求解的仿真实例，并分析了新算法在防止早熟收敛方面的特性。     

基于局部搜索的并行扩展规则推理方法

扩展规则推理方法在经典的可满足性问题求解中已得到广泛应用,若干个基于扩展规则的推理方法已被提出,皆得到国内外的认可,例如完备的NER,IMOMH_IER,PPSER算法以及基于局部搜索的不完备算法ERACC等,都具有良好的求解效果.其中,ERACC算法是当前扩展规则求解器中求解效率最高、能力最强的算法.但是,串行的ER...     

基于分区和分层搜索的并行粒子群算法*

为提高粒子群优化算法在优化问题中的效率,提出了并行粒子群优化算法(SLPSO)。其基本思想是并行机制+解空间压缩+分层搜索。主要工作包括：搜索空间划分为n个区,由n个子群并行搜索,将搜索结果最好的作为指定的搜索空间,即将搜索空间缩小到原解空间的(1/n);提出了粒子群两层划分模型,底层利于扩大搜索范围,上层利于全局精细搜索。在四个基准函数上的优化实验表明,新方法比经典的IPPSO并行粒子群算法在解的精度上提高了80.37%。     

基于年龄动力学模型的自适应种群演化算法

本文针对演化算法中的自适应动态种群问题,探讨了年龄动力学模型,给出了简化的模型框架,提出了基于该模型的自适应种群演化算法,实现了对进化种群规模的动态控制 。实验表明,该算法比固定种群规模的经典算法具有更好的性能。     

用协同演化并行PSO重构扩展的超二次曲面模型

针对用传统方法难以求解的扩展的超二次曲面三维模型参数拟合问题,提出了用协同演化的并行粒子群优化算法求解的新方法。通过对扩展的超二次曲面三维表示特性的研究,设计和实现了基于岛屿群体模型的并行粒子群优化算法,并用协同演化的思想,将约束非线性优化转化为极小极大问题进行求解。实验结果表明用协同演化的并行粒子群优化算法重构扩展的超二次曲面三维模型,扩大了模型表示能力,建模精确且效率高。     

基于多目标演化算法的SOC设计空间搜索策略

针对参数化SOC设计空间的复杂性,提出了一利新的搜索策略,该搜索策略以多目标演化算法为核心,依据参数依赖性概念对设计空间进行大幅度的缩减并使用空间阈值技巧增加了策略的适应性.通过与敏感度分析搜索策略的实验对比,证明了该策略在得到更优配置的同时可以显著缩短搜索时间.     

Asynchronous parallel simulation of parallel programs

Parallel simulation of parallel programs for large datasets has been shown to offer significant reduction in the execution time of many discrete event models. The paper describes the design and implementation of MPI-SIM, a library for the execution driven parallel simulation of task and data parallel programs. MPI-SIM can be used to predict the performance of existing programs written using MPI for message passing, or written in UC, a data parallel language, compiled to use message passing. The simulation models can be executed sequentially or in parallel. Parallel execution of the models are synchronized using a set of asynchronous conservative protocols. The paper demonstrates how protocol performance is improved by the use of application-level, runtime analysis. The analysis targets the communication patterns of the application. We show the application-level analysis for message passing and data parallel languages. We present the validation and performance results for the simulator for a set of applications that include the NAS Parallel Benchmark suite. The application-level optimization described in the paper yielded significant performance improvements in the simulation of parallel programs, and in some cases completely eliminated the synchronizations in the parallel execution of the simulation model     

Asynchronous parallel discrete event simulation

Complex models may have model components distributed over a network and generally require significant execution times. The field of parallel and distributed simulation has grown over the past fifteen years to accommodate the need of simulating the complex models using a distributed versus sequential method. In particular, asynchronous parallel discrete event simulation (PDES) has been widely studied, and yet we envision greater acceptance of this methodology as more readers are exposed to PDES introductions that carefully integrate real-world applications. With this in mind, we present two key methodologies (conservative and optimistic) which have been adopted as solutions to PDES systems. We discuss PDES terminology and methodology under the umbrella of the personal communications services application     

Asynchronous problems on SIMD parallel computers

One of the essential problems in parallel computing is: Can SIMD machines handle asynchronous problems? This is a difficult, unsolved problem because of the mismatch between asynchronous problems and SIMD architectures. We propose a solution to let SIMD machines handle general asynchronous problems. Our approach is to implement a runtime support system which can run MIMD-like software on SIMD hardware. The runtime support system, named P kernel, is thread-based. There are two major advantages of the thread-based model. First, for application problems with irregular and/or unpredictable features, automatic scheduling can move some threads from overloaded processors to underloaded processors. Second, and more importantly, the granularity of threads can be controlled to reduce system overhead. The P kernel is also able to handle bookkeeping and message management, as well as to make these low-level tasks transparent to users. Substantial performance has been obtained on Maspar MP-1     

Single-agent parallel window search

Parallel window search is applied to single-agent problems by having different processes simultaneously perform iteration of Iterative-Deepening-A* (IDA*) on the same problem but with different cost thresholds. This approach is limited by the time to perform the goal iteration. To overcome this disadvantage, the authors consider node ordering. They discuss how global node ordering by minimum h among nodes with equal f=g+h values can reduce the time complexity of serial IDA* by reducing the time to perform the iterations prior to the goal iteration. Finally, the two ideas of parallel window search and node ordering are combined to eliminate the weaknesses of each approach while retaining the strengths. The resulting approach, called simply parallel window search, can be used to find a near-optimal solution quickly, improve the solution until it is optimal, and then finally guarantee optimality, depending on the amount of time available     

Deterministic parallel backtrack search

The backtrack search problem involves visiting all the nodes of an arbitrary binary tree given a pointer to its root subject to the constraint that the children of a node are revealed only after their parent is visited. We present a fast, deterministic backtrack search algorithm for a p-processor COMMON CRCW-PRAM, which visits any n-node tree of height h in time O((n/p+h)(logloglogp)²). This upper bound compares favourably with a natural Ω(n/p+h) lower bound for this problem. Our approach embodies novel, efficient techniques for dynamically assigning tree-nodes to processors to ensure that the work is shared equitably among them.     

Variable population size and evolution acceleration: a case study with a parallel evolutionary algorithm

With current developments of parallel and distributed computing, evolutionary algorithms have benefited considerably from parallelization techniques. Besides improved computation efficiency, parallelization may bring about innovation to many aspects of evolutionary algorithms. In this article, we focus on the effect of variable population size on accelerating evolution in the context of a parallel evolutionary algorithm. In nature it is observed that dramatic variations of population size have considerable impact on evolution. Interestingly, the property of variable population size here arises implicitly and naturally from the algorithm rather than through intentional design. To investigate the effect of variable population size in such a parallel algorithm, evolution dynamics, including fitness progression and population diversity variation, are analyzed. Further, this parallel algorithm is compared to a conventional fixed-population-size genetic algorithm. We observe that the dramatic changes in population size allow evolution to accelerate.     

Asynchronous and implicitly parallel evolutionary computation models

This paper presents the design and the application of asynchronous models of parallel evolutionary algorithms. An overview of the existing parallel evolutionary algorithm (PEA) models and available implementations is given. We present new PEA models in the form of asynchronous algorithms and implicit parallelization, as well as experimental data on their efficiency. The paper also discusses the definition of speedup in PEAs and proposes an appropriate speedup measurement procedure. The described parallel EA algorithms are tested on problems with varying degrees of computational complexity. The results show good efficiency of asynchronous and implicit models compared to existing parallel algorithms.     

Asynchronous analysis of parallel dynamic programming algorithms

We examine a very simple asynchronous model of parallel computation that assumes the time to compute a task is random, following some probability distribution. The goal of this model is to capture the effects of unpredictable delays on processors, due to communication delays or cache misses, for example. Using techniques from queueing theory and occupancy problems, we use this model to analyze two parallel dynamic programming algorithms. We show that this model is simple to analyze and correctly predicts which algorithm will perform better in practice. The algorithms we consider are a pipeline algorithm, where each processor i computes in order the entries of rows i, i+p, and so on, where p is the number of processors; and a diagonal algorithm, where entries along each diagonal extending from the left to the top of the table are computed in turn. It is likely that the techniques used here can be useful in the analysis of other algorithms that use barriers or pipelining techniques     

基于多尺度特征实现超参进化的野生菌分类研究与应用

在我国,因误食不可食用野生菌而导致中毒的事件频发,尤其是云南等西南地区,由于野生菌种类的类间特征差异较小,且实际场景下的图像背景复杂,仅靠肉眼分辨困难。目前虽然有多种方法可对野生菌进行分类,且最为可靠的方法为分子鉴定法,但该方法耗时长、门槛高,不适合进行实时分类检测。针对这一问题,提出了一种基于深度学习的方法,即使用注意力机制(CBAM),配合多尺度特征融合,增加 Anchor层,利用超参数进化思想对其模型训练时的超参数进行调整,从而提升识别精度。与常见的目标检测网络 SSD,Faster_Rcnn 和 Yolo 系列等进行对比,该模型能更准确地对野生菌进行分类检测;经过模型改进后,相较于原Yolov5,Map 提升 3.7%,达到 93.2%,准确率提升 1.3%,召回率提升 1.0%,且模型检测速度提升 2.3%;相较于 SSD,Map 提升 14.3%。最终将模型简化,部署到安卓设备上,增加其实用性,解决当前因野生菌难以辨别而误食不可食用野生菌导致中毒的问题。