A reactive extension of the OpenMusic visual programming language

Objectives: OpenMusic (OM) is a domain-specific visual programming language designed for computer-aided music composition. This language based on Common Lisp allows composers to develop functional processes generating or transforming musical data, and to execute them locally by demand-driven evaluations. As most historical computer-aided composition environments, OM relies on a transformational declarative paradigm, which is hard to conciliate with reactive data-flow (an evaluation scheme more adequate to the development of interactive systems). We propose to link these two evaluation paradigms in the same and consistent visual programming framework.Methods: We establish a denotational semantics of the visual language, which gives account for its demand-driven evaluation mechanism and the incremental construction of programs. We then extend this semantics to enable reactive computations in the functional graphs.Results: The resulting language merges data-driven executions with the existing demand-driven mechanism. A conservative implementation is proposed.Conclusions: We show that the incremental construction of programs and their data-driven and demand-driven evaluations can be smoothly integrated in the visual programming workflow. This integration allows for the propagation of changes in the programs, and the evaluation of graphically designed functional expressions as a response to external events, a first step in bridging the gap between computer-assisted composition environments and real-time musical systems.     

A surrogate-based optimization method with RBF neural network enhanced by linear interpolation and hybrid infill strategy

In engineering, it is computationally prohibitive to directly employ costly models in optimization. Therefore, surrogate-based optimization is developed to replace the accurate models with cheap surrogates during optimization for efficiency. The two key issues of surrogate-based optimization are how to improve the surrogate accuracy by making the most of the available training samples, and how to sequentially augment the training set with certain infill strategy so as to gradually improve the surrogate accuracy and guarantee the convergence to the real global optimum of the accurate model. To address these two issues, a radial basis function neural network (RBFNN) based optimization method is proposed in this paper. First, a linear interpolation (LI) based RBFNN modelling method, LI-RBFNN, is developed, which can enhance the RBFNN accuracy by enforcing the gradient match between the surrogate and the trend observed from the training samples. Second, a hybrid infill strategy is proposed, which uses the surrogate prediction error based surrogate lower bound as the optimization objective to locate the promising region and meanwhile employs a linear interpolation-based sequential sampling approach to improve the surrogate accuracy globally. Finally, extensive tests are investigated and the effectiveness and efficiency of the proposed methods are demonstrated.     

IPV6技术在数字化校园建设中安全防范研究

随着校园网的日益发展,IPv6网络在我国数字化校园网中广泛部署,其安全问题也日益突出。基于我院数字化校园网庞大的实验环境,该文从分析IPV6数字化校园网的安全特点入手,对IPV6技术在我院数字化校园建设中体现的安全问题进行了分析,阐述了保证IPv6对解决我院数字化校园网安全实现的一些策略。     

浅析计算机网络维护工作和管理

随着现代社会的进步,科学技术取得了飞速发展,计算机网络得到了大量普及,极大地促进了社会生产和人们生活水平的提高,对社会的整体发展起着至关重要的作用.本次研究将从网络维护、管理的意义和应注意的问题出发,对网络网络维护与管理相关策略进行深入分析和探究.     

基于多保留策略的复合型遗传算法及其收敛性分析

遗传算法(GA)作为一种新型的智能优化方法,以其结构简单、适应性强等特点在众多实际领域取得了成功的应用,但存在计算复杂度大、易于局部收敛等方面的不足。本文在分析现有遗传操作的不足和生物进化的基本特征基础上,从提高进化效率的角度出发,提出基于多保留策略的复合型遗传算法(简称MRS-CGA);进而利用Markov链理论和仿真技术,从不同的层面分析了算法的性能。讨论结果表明,算法从本质上推广了常规的GA,在计算效率和收敛性能上均明显地优于常规的GA。     

网格环境下基于传输代价的副本优化策略*

在深入分析影响副本策略性能的各种因素的基础上,将多种因素和传输代价联系起来进行建模,提出一种副本优化策略。优化策略基于传输代价,综合考虑文件访问次数、大小、存在时间等多种因素,并充分利用文件访问次数的集合特征,提供了一个动态、全局的副本管理方法。在网格仿真器OptorSim中对基于传输代价的优化策略进行了实现和评估分析。实验分析证明,优化后的副本策略较现有策略有明显优势。     

秦岭北麓休闲产业带的开发策略

采用理论和实证相结合的方法,以秦岭北麓为实证对象,对其自然地理环境和社会经济概况以及山区资源状况进行了定性和定量分析,对秦岭北麓休闲产业发展的资源—市场—产品进行联动分析的基础上,构建出秦岭北麓的休闲产业带的范围,设计出休闲产业的产品类型,并提出秦岭北麓休闲产业带开发的总体策略.     

湖北企业国际化经营的政治风险与规避策略探析

政治风险是企业国际化经营中必须考虑的重要风险.现阶段湖北企业国际化经营所面临的政治风险,既决定于国外对湖北企业国际化经营所持的态度和看法,又决定于湖北企业国际化经营的现状和水平.因此湖北企业应从世情、国情、企情的新变化出发,依据企业国际化经营的特点,制定规避企业国际化经营政治风险的策略.     

Study on Steering Control Strategy for High-Speed Tracked Vehicle with Hydrostatic Drive

Steering control strategy for high-speed tracked vehicle with hydrostatic drive is designed based on analyzing the fundamental steering theories of the hydrostatic drive tracked vehicle. The strategy is completed by the cooperation between integrated steering control unit and pump & motor displacement controller. The steering simulation is conducted by using Simulink of Matlab. It is indicated that this steering control strategy can reduce the average vehicle speed automatically to achieve the drivers expected steering radius exactly in the case of ensuring not exceeding the system pressure threshold and no sideslip.     

汕头市城市定位与可持续发展战略研究

城市定位就是对城市未来发展方向和发展目标的拟定,是城市规划建设的重要组成部分.文章在对城市定位的涵义理解和城市发展战略思考的基础上,分析了城市定位与城市发展战略的互动机制,提出了汕头市新时期的城市定位.同时,提出并详细探讨了基于城市定位的汕头市可持续发展战略构想.