在并行分布式图匹配方案中的分割算法实现

描述了在并行分布式图匹配算法中的子图分割算法。通过寻找一个相关矩阵进行图变换,从而使这种分割容易而且有效。同时,这种分割降低了相互关联的复杂性,提高了并行机并行运算的效率。     

Modelling non-Gaussian random fields using transformations and Hermite polynomials

In the context of modelling residual roughness on nominally flat moderately polished metal surfaces, a method is proposed for solving problems related to sample function properties and/or special points such as maxima, minima, saddle points for random fields having non-Gaussian height distributions by recasting them in terms of the corresponding problems for the much more tractable Gaussian random fields by means of transformations. Special reference is made to the expansion of the transformations in series of Hermite polynomials. While the use of Hermite polynomials in connection with transformations of random fields and the useful results they yield with regard to covariance functions are well known, this paper derives the most general explicit formula for the expectation of any product of several Hermite polynomials in correlated Gaussian arguments thereby allowing their application to the higher moments of the transformed random field, in particular, to the third moment, which may be used to measure skewness.     

Constant false alarm rate detection in Pareto Type II clutter

Recent investigations have shown that the Pareto class of models provide a valid approximation for the statistical structure of the backscattering from the sea, for high resolution X-band maritime surveillance radar. This has stimulated the research and development of non-coherent radar detection processes for operation in such a clutter model environment. Using data from Defence Science and Technology Group's X-band radar the application of a Pareto Type I clutter model has been justified, which has facilitated the development of sliding window decision processes. However it has been found that when these detectors are applied to synthetic target detection in real data there are some issues resulting in substantial detection losses. In order to rectify this it is necessary to investigate the development of radar detection schemes under a Pareto Type II clutter model assumption. Using a transformation approach for radar detector design it will be shown that it is possible to construct detection processes that achieve the constant false alarm rate property with respect to the Pareto shape parameter, as in the Pareto Type I case, while requiring a priori knowledge of the Pareto scale parameter. Performance analysis includes application to real X-band clutter returns with synthetic target models.     

Scale-up of binder agglomeration processes

This review article describes scale-up of batch and continuous granulation processes where liquid binder is added to fine powder in order to form a granular product. The technical goal of scale-up is to maintain similarity of critical product attributes as the production scale and/or throughput of a manufacturing process is increased. This paper provides a framework for scaling-up that considers critical process transformations in relation to the desired product attributes. A similar approach can be taken in developing process control strategies. In any agglomeration process, transformations can be used to describe how raw materials (typically fine powders and liquid binders) are converted into a granular product. Often the critical product attributes are characterized on the scale of individual granules (e.g., size, shape, porosity, mechanical strength, etc.). On the other hand, industrial scale-up requires predictive relations for the sizing, design and operation of process equipment. Considering scale-up on the basis of transformations is one way to link the macro-scale equipment decisions with micro-scale product attributes. This approach can be applied to the scale-up of batch and/or continuous granulation processes as well as transitioning from small batch prototypes to continuous production circuits.     

HLA/RTI仿真框架中的坐标转换及其实现机制

为了保证分布交互仿真的互操作、可重用和时空一致性,应在仿真运行支撑环境(RTI)中提供不同仿真应用的坐标转换功能。文章首先分析了坐标转换的必要性,然后介绍了常用坐标系及其相互转换关系,最后探讨了HLA/RTI仿真框架中的坐标转换实现机制,重点解决了如何转换、何时转换、由谁转换、如何标示所用坐标系、如何调用坐标转换模块等问题,并建议在当前的对象模型模板(OMT)增加有关对象所用坐标系的说明。     

Using Bytecode Instruction Counting as Portable CPU Consumption Metric

Accounting for the CPU consumption of applications is crucial for software development to detect and remove performance bottlenecks (profiling) and to evaluate the performance of algorithms (benchmarking). Moreover, extensible middleware may exploit resource consumption information in order to detect a resource overuse of client components (detection of denial-of-service attacks) or to charge clients for the resource consumption of their deployed components. The Java Virtual Machine (JVM) is a predominant target platform for application and middleware developers, but it currently lacks standard mechanisms for resource management.In this paper we present a tool, the Java Resource Accounting Framework, Second Edition (J-RAF2), which enables precise CPU management on standard Java runtime environments. J-RAF2 employs a platform-independent CPU consumption metric, the number of executed JVM bytecode instructions. We explain the advantages of this approach to CPU management and present five case studies that show the benefits in different settings.     

Semi-local Model of Computations on Graphs to Break the Local Symmetry: Work in Progress

We consider finite connected undirected graphs without self-loops as a model of computer networks. The nodes of the graph represent computers or processors, while the edges of the graph correspond to the links between them. We present a model of distributed computations, called semi-local. This extension of the classical local model breaks the local symmetry. As a result, many useful tasks become deterministically solvable in every network assuming a very small initial knowledge about its graph representation. One of these tasks is a creation of a token in an arbitrary anonymous ring – an example of election of a leader. A semi-local solution to this problem is presented.     

基于本体映射的MDA模型转换研究

模型转换是MDA框架中的重要环节之一,以往的模型转换方法可能会因为缺乏语义保证而出现错误。本文通过本体映射来研究MDA模型转换,提出实现MDA模型语义层转换的方法,并提高模型转换的效率和准确率。     

Java Bytecode Transformations for Efficient, Portable CPU Accounting

Resource management is essential to build reliable middleware and to host potentially untrusted software components. Resource accounting allows to study and optimize program performance and to charge users for the resource consumption of their deployed components, while resource control can limit the resource consumption of components in order to prevent denial-of-service attacks. In the approach presented here, program transformations enable resource management in Java-based environments, even though the underlying runtime system may not expose information concerning the resource consumption of applications. We present a fully portable program transformation scheme to enhance standard Java runtime systems with mechanisms for CPU management. We implemented several optimizations in order to reduce the overhead of our CPU accounting scheme. Detailed performance measurements quantify this overhead and show the impact of various optimizations.     

On transformation of authorization policies

In this paper, we propose a logic based approach to specify and to reason about transformation of authorization policies. The authorization policy is specified using a policy base which comprises a finite set of facts and access constraints. We define the structure of the policy transformation and employ a model-based semantics to perform the transformation under the principle of minimal change. Furthermore, we extend model-based semantics by introducing preference ordering to resolve possible conflicts during transformation of policies. We also discuss the implementation of the model-based transformation approach and analyse the complexity of the algorithms introduced. Our system is able to represent both implicit and incomplete authorization requirements and reason about nonmonotonic properties.