一种基于Petri网的网络服务兼容性分析方法

针对目前基于网络服务业务过程执行语言(BPEL)的网络服务合成方法缺乏网络服务的兼容性分析机制,不能保证基于网络服务技术的业务过程正确执行的问题,建立了一种能从形式化的角度描述网络服务的接口交互情况的基于Petri网的多元工作流组合网模型,提出了一种能更快地获得网络服务可用性结果的网络服务兼容性判断算法.最后,提出了基于该算法的原型系统架构.     

利用Petri网求解U型装配线平衡问题

提出了一种基于Petri网的启发式算法用于求解第一类U型装配线平衡问题,算法利用Petri网的可达分析和托肯的移动来决定可分配的作业元素,并按照最小化工作站空闲时间原则从前向后和从后向前两个方向同时分派作业元素到工作站。算法编程简单,可用于快速求解大规模问题。通过对大量问题集的测试验证,说明了算法的有效性。     

基于Petri网的Web服务组合化简方法的研究

指出一种基于Petri网的Web服务组合的化简方法,此方法包括建模和化简两个阶段。首先,Petri网结合工作流模式建模Web服务组合:然后通过Petri网的三种性质(可达性,安全性以及死锁)定义出Web服务组合结构,最后运用流程化简规则化简Web服务组合。     

基于带抑止弧的Petri网的软件保护技术应用序列构建方法

基于软件保护领域中多种软件保护技术之间存在不同依赖关系的情况,针对求解有效的软件保护技术应用序列问题,提出了一种基于带抑止弧的Petri网建模分析的求解方法。首先分类并建立4种基本的软件保护技术依赖关系的Petri网模型,包括前向/后向必须依赖关系和前向/后向禁止依赖关系;根据实际应用场景建立相应的复合依赖关系Petri网模型,并绘制其可达标识图;在可达标识图中定位满足需求的标识,求解得从初始标识到此标识的一条变迁序列所对应的软件保护技术应用序列即为所求序列。最后,通过实验证明了此方法的有效性。     

控制软件设计与验证计算机辅助系统

介绍了控制软件设计与验证系统的原理与实现过程,给出顺序功能图（Sequential Function Charts,即SFC）需求说明语言到系统Petri网模型的转化算法和系统几种异常现象的验证算法,讨论了系统实现的若干关键技术,最后通过例子演示了系统的操作过程。     

基于进程网模型的仿真技术研究

进程网是一种新的融合进程代数特征的Petri网模型。具有传统Petri网的图形化表示方式,又具有进程代数的语法形式。本文基于进程网系统,针对进程网建模工具Prn Tools,提出适合其模型的仿真算法,包括实现组件的逻辑关系,组件的点火判定,点火及仿真的图形化表示,以及仿真结束状态图的生成。实验结果表明Prn Tools仿真功能得到实现,该算法有效地实现了针对进程网的仿真技术。     

生物计算网格中的在线调度技术研究

研究了在异构网格环境下的生物应用集成,定义了服务的提供者、部署者和使用者三种用户角色,设计了网格环境下的服务和资源整合机制,重点实现了用户管理以及作业调度控制等功能.根据计算资源的异构特点,设计了多种启发式调度算法.考虑到生物计算应用的不同类型,提出了自适应调度算法,该算法根据应用的特点动态选择启发式调度算法.实验表明,非阻塞调度优于阻塞调度方式;自适应调度算法比静态的在线调度算法有更好的性能,而在异构的网络中,带宽优先调度算法的性能比其他静态调度算法性能更好.     

信任协商策略的Petri网建模分析方法

对Peer-to-Peer网络环境下信任协商和信任协商策略进行了定义和形式化描述,提出了一种基于Petri网模型的信任协商策略建模分析方法,将资源、证书和资源访问策略映射为Petri网网元进行建模,通过可达分析寻找最优资源解锁序列.和其他信任协商策略建模方法相比,该方法具有较好的性能.     

基于对象Petri网的电网调度操作票任务分解方法

本文提出了基于面向对象Petri网技术的操作票任务分解方法,对分解后的单一操作任务再使用基本Petri网进行推理,从而解决了基本Petri网在建立电网调度操作票专家系统规则库时遇到的组合爆炸问题。通过分析给出了算法的对象划分、结构封装、对象间的消息传递关系以及图形化的建模;所设计的对象结构及对象关系保证了系统的安全性;最后结合算例阐述了具体的技术方案。算例结果表明了该方法的有效性。     

基于模糊Petri网考虑制造约束的零件

加工方案决策是计算机辅助工艺规划中一直未能完全解决的关键问题.首先,在给出Petri网系统和T_不变量定义的基础上,根据Petri网原理和产生式规则建立一个基于模糊规则的零件表面加工方案Petri网模型;然后,根据Petri网T_不变量在考虑制造资源约束的条件下,提出一种新的可选加工方案T_不变量生成方法;最后,通过实例验证了所提方法的有效性.实例结果表明,采用作者提出的决策方法能够获得零件表面加工的最优/次优工艺方案     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.