基于Pi演算的BPMN编排模式

针对业务流程建模标记（BPMN）无法依靠自身对编排进行形式化分析的问题,提出用Pi演算描述BPMN编排模式,实现对BPMN编排的描述。BPMN编排模式是服务交互模式的BPMN表达。实验结果表明,该方法能够找到并排除BPMN编排中的死锁。     

用BPMN辅助整合Web Services

介绍了用BPMN设计整合Web Service,并产生Web Service描述语言(WSDL)形式的可执行规范语言,以及利用WSDL可以转换成业务流程管理标识(BPMN)的方法,动态地将已存在的Web Service通过BPMN图形化建模方法进行整合.鉴于BPMN的图形化设计,可以选择喜欢的可执行语言来实现该整合方案,主要采用与BPMN密切关联的Web Service语言--面向服务的业务流程可执行语言(BPEL4WS).     

业务流程模型的BPEL实现

由于BPEL语言的XML表示十分冗长以及没有形式化的分析技术,其抽象级别不适合用于业务流程分析和设计.而业务流程分析师和设计者更容易接受高级别的抽象模式,例如BPMN(Business Process Modeling Notation).很多建模工具支持BPMN,但是到目前为止没有系统可直接执行BPMN模型.因此,需...     

基于BPMN辅助构建Web Services的研究

介绍了Web Services以及业务流程建模标记(BPMN)和Web服务的业务流程执行语言(BPEL4WS)，并且利用BPMN和BPEL4WS构建Web Services组件，建立Web服务模型，以整合各种企业应用平台，把企业业务由企业内部拓展到Internet上，从而达到企业资源的优化配置，实现了应用程序间的通用的互操作性以及企业间的信息交流，以适应复杂多变的商务环境。     

基于Pi验算的信息化系统流程研究与设计

软件建模是把现实世界的需求抽象成概念模型,软件编码是把概念模型转变成能够运行的代码,在建模阶段,针对传统的UML即统一建模语言对信息系统业务流程的建模,无法严谨地定义和模拟信息系统的业务流程,不能保证流程本身的正确性和一致性等问题.以物流订单流程为例,研究BPMN表达业务流程及与形式化语言之间的转换,用形式化描述语言Pi演算描述和验证BPMN已描述的信息系统业务流程,通过JPDL直接定义出已通过Pi演算验证的订单流程,并应用于工作流引擎JBPM中,从而保证应用系统业务流程的正确性.     

一种支持流程整合的业务协议组合代数

针对基于Web的业务流程建模问题,将业务流程的参与者抽象为角色,采用基于角色间交互的协议对业务流程进行建模,构造抽象的业务流程模板,提出一个业务协议组合代数,构造一组协议组合算子,即顺序、并发、选择和迭代,并证明该代数的一些相关性质,分析协议的相似性,从而为替换协议提供理论依据。     

服务构件模型的研究与设计

针对如何更高效和准确地将已存在的Web服务集成到业务流程中,提出了服务构件模型。该模型以Web服务为业务功能实现的基础,用BPMN建模用户需求,输出为可执行的BPEL模型。该服务构件模型内部对原子服务进行了重新定义,便于服务的查找;而且加入了服务的QoS特征,便于服务的选择。     

Web环境下基于协议组合代数的业务流程整合方法

采用协议对基于Web的业务流程建模是当前研究的一个新方向.业务协议是对参与业务过程的业务步骤的描述.本文将多个参与者参与的业务步骤抽象为参与者之间的交互,采用基于交互的协议对业务流程建模,提出了一个业务协议组合代数,构造了一组协议组合算子,并证明了该代数的一些相关性质;本文还对协议的相似性进行了分析,为替换协议的选择奠定了基础.文章还通过一个流程组合实例说明了基于协议组合代数的业务流程整合过程.     

基于Pi-演算的工作流模式描述

工作流模式包含了业务流程的基本特征和共性,其实现依赖于具体的流程建模语言或方法.Pi-演算是一种进程代数,可以应用于业务流程的形式化建模.本文使用Pi-演算作为业务流程形式化的工具,对存在多种BPMN表示的工作流模式进行形式化建模,以探究工作流模式Pi-演算的描述,检验Pi-演算对业务流程行为特征的表现能力.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).