Patterns-based evaluation of open source BPM systems: The cases of jBPM, OpenWFE, and Enhydra Shark

In keeping with the proliferation of free software development initiatives and the increased interest in the business process management domain, many open source workflow and business process management systems have appeared during the last few years and are now under active development. This upsurge gives rise to two important questions: What are the capabilities of these systems? and How do they compare to each other and to their closed source counterparts? In other words: What is the state-of-the-art in the area?. To gain an insight into these questions, we have conducted an in-depth analysis of three of the major open source workflow management systems – jBPM, OpenWFE, and Enhydra Shark, the results of which are reported here. This analysis is based on the workflow patterns framework and provides a continuation of the series of evaluations performed using the same framework on closed source systems, business process modelling languages, and web-service composition standards. The results from evaluations of the three open source systems are compared with each other and also with the results from evaluations of three representative closed source systems: Staffware, WebSphere MQ, and Oracle BPEL PM. The overall conclusion is that open source systems are targeted more toward developers rather than business analysts. They generally provide less support for the patterns than closed source systems, particularly with respect to the resource perspective, i.e. the various ways in which work is distributed amongst business users and managed through to completion.

Realising dead path elimination in BPMN

The Web Service Business Process Execution Language (BPEL) lacks any standard graphical notation. Various efforts have been undertaken to visualize BPEL using the Business Process Modelling Notation (BPMN). Although this is straightforward for the majority of concepts, it is tricky for the full BPEL standard, partly due to the insufficiently specified BPMN execution semantics. The upcoming BPMN 2.0 revision will provide this clear semantics. In this paper, we show how the dead path elimination (DPE) capabilities of BPEL can be expressed with this new semantics and discuss the limitations. We provide a generic formal definition of DPE and discuss resulting control flow requirements independent of specific process description languages.

The internet of services and USDL

A prominent research focus, especially in the context of EU public funding, has been the systematic use of the Internet for new ways of value creation in the services sector. This idea of service networks in the Internet, frequently dubbed the Internet of Services or Web service ecosystems, wants to make services tradable in digital media. In order to enable communication and trade between providers and consumers of services, the Internet of Services requires a standard that creates a "commercial envelope" around a service. This is where the Unified Service Description Language (USDL) comes into play as a normative and balanced unification of service information. The unified description established by USDL is machine-processable, considers technical and business aspects of a service as well as functional and non-functional attributes.

Intrusion detection in distributed systems, an approach based on taint marking

This paper presents a new framework for distributed intrusion detection based on taint marking. Our system tracks information flows between applications of multiple hosts gathered in groups (i.e., sets of hosts sharing the same distributed information flow policy) by attaching taint labels to system objects such as files, sockets, Inter Process Communication (IPC) abstractions, and memory mappings. Labels are carried over the network by tainting network packets. A distributed information flow policy is defined for each group at the host level by labeling information and defining how users and applications can legally access, alter or transfer information towards other trusted or untrusted hosts. As opposed to existing approaches, where information is most often represented by two security levels (low/high, public/private, etc.), our model identifies each piece of information within a distributed system, and defines their legal interaction in a fine-grained manner. Hosts store and exchange security labels in a peer to peer fashion, and there is no central monitor. Our IDS is implemented in the Linux kernel as a Linux Security Module (LSM) and runs standard software on commodity hardware with no required modification. The only trusted code is our modified operating system kernel. We finally present a scenario of intrusion in a web service running on multiple hosts, and show how our distributed IDS is able to report security violations at each host level.

Social tagging, guppy effect and the role of interference : a quantum-inspired model for tags combination

Social tagging systems are shown to evidence a well known cognitive heuristic, the guppy effect, which arises from the combination of different concepts. We present some empirical evidence of this effect, drawn from a popular social tagging Web service. The guppy effect is then described using a quantum inspired formalism that has been already successfully applied to model conjunction fallacy and probability judgement errors. Key to the formalism is the concept of interference, which is able to capture and quantify the strength of the guppy effect.

Intranet Alman käytettävyydestä

Usability testing is a productive and reliable method for evaluating the usability of software. Planning and implementing the test and analyzing its results is typically considered time-consuming, whereas applying usability methods in general is considered difficult. Because of this, usability testing is often priorized lower than more concrete issues in software engineering projects. Intranet Alma is a web service, users of which consist of students and personnel of the University of Helsinki. Alma was published in 2004 at the opening ceremony of the university. It has 45 000 users, and it replaces several former university network services. In this thesis, the usability of intranet Alma is evaluated with usability testing. The testing method applied has been lightened to make its taking into use as easy as possible. In the test, six students each tried to solve nine test tasks with Alma. As a result concrete usability problems were described in the final test report. Goal-orientation was given less importance in the applied usability testing. In addition, the system was tested only with test users from the largest user group. Usability test found general usability problems that occurred no matter the task or the user. However, further evaluation needs to be done: in addition to the general usability problems, there are task-dependent problems, solving of which requires thorough gathering of users goals. In the basic structure and central functionality of Alma, for example in navigation, there are serious and often repeating usability problems. It would be of interest to verify the designed user interface solutions to these problems before taking them into use. In the long run, the goals of the users, that the software is planned to support, are worth gathering, and the software development should be based on these goals.

Kirkkoon kuuluminen Helsingin osa-alueilla

In Helsinki's evangelical lutheran congregations, the share of the people being members of that church compared with all the people living in their specific geographical areas varies from 62,4 per cent in Paavali to 80,7 per cent in Munkkiniemi. The boundaries of the congregations are about to be redrawn to level the differences in the congregations. In this thesis, the reasons of the differences in Helsinki s districts were studied closer. The data consisted of statistical information gathered from the Population Information System of Finland. It included information by age groups about the population register keeper, marital status, native tongue, level of education and gender in the end of 2005. Additional data was gathered from Helsinki Region Statistics web service. It included information about the dwelling, level of income and main activities of the inhabitants in the districts. The main method was stepwise linear regression. Minor methods were crosstabulation and correlation matrixes. The result of the study was a statistical model that explains 72,2 per cent of the variation of the shares in the congregations. The dependent variable was the share of the people being members of evangelical lutheran church in the dirstricts. The independent variables were the share of the people having other than Finnish or Swedish as their native tongue, the share of rented apartments, the shares of apartments including four rooms and a kitchen, the share of detached houses in the districts and the shares of women and people with no income in the districts. The independent variables present in the model depict the amount of foreigners, dwellings, gender and the level of income of the population. The high share of foreigners, people with no income and rented apartments explain the low share of the people being members of evangelical lutheran church. On the contrary, the high share of the people being members of evangelical lutheran church in the district is explained by the large apartments, detached houses and amount of women living there.

FIN-CLARIN: A Framework for Depositing and Disseminating Language Resources for R&D

Researchers and developers in academia and industry would benefit from a facility that enables them to easily locate, licence and use the kind of empirical data they need for testing and refining their hypotheses and to deposit and disseminate their data e.g. to support replication and validation of reported scientific experiments. To answer these needs initially in Finland, there is an ongoing project at University of Helsinki and its collaborators to create a user-friendly web service for researchers and developers in Finland and other countries. In our talk, we describe ongoing work to create a palette of extensive but easily available Finnish language resources and technologies for the research community, including lexical resources, wordnets, morphologically tagged corpora, dependency syntactic treebanks and parsebanks, open-source finite state toolkits and libraries and language models to support text analysis and processing at customer site. Also first publicly available results are presented.

DockYard-a repository to assist modeling of protein-protein docking

In the absence of interlogs, building docking models is a time intensive task, involving generation of a large pool of docking decoys followed by refinement and screening to identify near native docking solutions. This limits the researcher interested in building docking methods with the choice of benchmarking only a limited number of protein complexes. We have created a repository called dockYard (http://pallab.serc.iisc.ernet.in/dockYard), that allows modelers interested in protein-protein interaction to access large volume of information on protein dimers and their interlogs, and also download decoys for their work if they are interested in building modeling methods. dockYard currently offers four categories of docking decoys derived from: Bound (native dimer co-crystallized), Unbound (individual subunits are crystallized, as well as the target dimer), Variants (match the previous two categories in at least one subunit with 100% sequence identity), and Interlogs (match the previous categories in at least one subunit with >= 90% or >= 50% sequence identity). The web service offers options for full or selective download based on search parameters. Our portal also serves as a repository to modelers who may want to share their decoy sets with the community.

PocketAlign A Novel Algorithm for Aligning Binding Sites in Protein Structures

A fundamental task in bioinformatics involves a transfer of knowledge from one protein molecule onto another by way of recognizing similarities. Such similarities are obtained at different levels, that of sequence, whole fold, or important substructures. Comparison of binding sites is important to understand functional similarities among the proteins and also to understand drug cross-reactivities. Current methods in literature have their own merits and demerits, warranting exploration of newer concepts and algorithms, especially for large-scale comparisons and for obtaining accurate residue-wise mappings. Here, we report the development of a new algorithm, PocketAlign, for obtaining structural superpositions of binding sites. The software is available as a web-service at http://proline.physicslisc.emetin/pocketalign/. The algorithm encodes shape descriptors in the form of geometric perspectives, supplemented by chemical group classification. The shape descriptor considers several perspectives with each residue as the focus and captures relative distribution of residues around it in a given site. Residue-wise pairings are computed by comparing the set of perspectives of the first site with that of the second, followed by a greedy approach that incrementally combines residue pairings into a mapping. The mappings in different frames are then evaluated by different metrics encoding the extent of alignment of individual geometric perspectives. Different initial seed alignments are computed, each subsequently extended by detecting consequential atomic alignments in a three-dimensional grid, and the best 500 stored in a database. Alignments are then ranked, and the top scoring alignments reported, which are then streamed into Pymol for visualization and analyses. The method is validated for accuracy and sensitivity and benchmarked against existing methods. An advantage of PocketAlign, as compared to some of the existing tools available for binding site comparison in literature, is that it explores different schemes for identifying an alignment thus has a better potential to capture similarities in ligand recognition abilities. PocketAlign, by finding a detailed alignment of a pair of sites, provides insights as to why two sites are similar and which set of residues and atoms contribute to the similarity.

Executing SADI services in Galaxy

Background: In recent years Galaxy has become a popular workflow management system in bioinformatics, due to its ease of installation, use and extension. The availability of Semantic Web-oriented tools in Galaxy, however, is limited. This is also the case for Semantic Web Services such as those provided by the SADI project, i.e. services that consume and produce RDF. Here we present SADI-Galaxy, a tool generator that deploys selected SADI Services as typical Galaxy tools. Results: SADI-Galaxy is a Galaxy tool generator: through SADI-Galaxy, any SADI-compliant service becomes a Galaxy tool that can participate in other out-standing features of Galaxy such as data storage, history, workflow creation, and publication. Galaxy can also be used to execute and combine SADI services as it does with other Galaxy tools. Finally, we have semi-automated the packing and unpacking of data into RDF such that other Galaxy tools can easily be combined with SADI services, plugging the rich SADI Semantic Web Service environment into the popular Galaxy ecosystem. Conclusions: SADI-Galaxy bridges the gap between Galaxy, an easy to use but "static" workflow system with a wide user-base, and SADI, a sophisticated, semantic, discovery-based framework for Web Services, thus benefiting both user communities.

事件驱动的BPEL引擎架构设计与实现

WS-BPEL(Web Service Business Process Execution Language，简称BPEL)是Web服务规范族中服务复合层的重要标准。BPEL支持通过对Web服务的编制(Orchestration)来构建业务流程，从而使编程人员能够集中关注业务逻辑。BPEL引擎系统是一个支持BPEL语言描述的业务流程运行的服务器中间件系统，使用BPEL引擎可以执行BPEL语言编写的业务流程。作为一个网络服务器系统，BPEL引擎将不可避免的处理大量的并发请求。如何设计实现BPEL引擎使之能高效的处理并发将是高性能BPEL引擎设计的关键问题。 并发服务器系统通常采用多线程和事件驱动两种并发模型。传统上大多数服务器软件都建立在多线程(或多进程)模型的基础上。但在高负载条件下，过多的线程和线程间的上下文切换会造成系统较大的开销，这些开销是导致系统性能下降的主要原因。事件驱动模型是一种只采用少量固定数量线程的并发模型，一般说来，它的伸缩性更好，并且有更高的处理效率。 本文对高并发服务器系统中所使用的事件驱动模型进行了分析和研究，并且结合BPEL语言规范的特点，提出了事件驱动的BPEL引擎实现技术方案。论文重点研究了BPEL事件结构和有限状态机(Finite State Machine，简称FSM)刻画BPEL流程和活动行为的原理，针对BPEL语言语法特点，构造了完整的BPEL FSM模型，包括了状态空间和基于ECA(Event-Condition-Action)模式的状态转移规则。 在基于事件驱动模型的BPEL引擎架构原理的指导下，我们设计并实现了基于事件驱动模型的OnceBPEL2.0引擎系统。并且，我们对采用多线程模型实现的OnceBPEL1.0系统和采用事件驱动模型实现的OnceBPEL2.0系统进行了性能测试和分析比较。从我们的测试数据和分析结果可以看出，采用事件驱动模型的OnceBPEL2.0系统比采用多线程模型的OnceBPEL1.0有了较大的性能提升。

从面向对象的遗留系统到面向服务架构的迁移方法

Migrating legacy system with web service is an effective and economic way of reusing legacy software in a SOA environment.In this paper,we present an approach for migrating a three-tie object-oriented legacy system to SOA environment.The key issue of the approach is about services identification from large numbers of classes.And we propose a bottom-up method to model the system with UML and identify services from UML then.This approach can be a reference to an auto-migrating process.

基于契约的客户需求驱动型供应链分销协调研究

供应链协调在国际供应链管理领域备受关注，是涉及多学科高度交叉、知识广泛集成的前沿热点研究领域。它综合了经济学、管理学、营销学、现代网络及信息科学等技术，通过供应链各利益实体之间竞争、协作，实现供应链整体效益的提升。其作为我国实现产业结构优化升级的重要途径，已经成为企业继自然资源、人力资本后的第三个利润增长源泉。 本论文在深入研究供应链管理、供应链协调及契约理论的基础上，分析指出了供应链契约协调研究发展的趋势。依据该趋势本文主要研究的内容是对当前供应链契约协调理论研究的补充和扩展。本文立足于解决我国供应链管理及协调中诸多实际问题，针对现代市场环境中客户需求个性化、多样性及不确定性的特点，研究了供应链契约的统一框架，方法及技术路线，重点研究了客户需求驱动的供应链分销契约协调问题，建立了不同条件下的契约优化模型，给出基于博弈均衡解的一系列证明，并分析了契约参数对供应链整体及各成员绩效的影响，最后基于SOA架构设计并实现了契约自动协商平台。论文的主要研究内容包括以下4个方面： 1. 建立了多对一供应链、确定性客户需求、完全信息下的契约优化模型。基于多个竞争的制造商和一个独立的、共同的零售商组成的多对一供应链分销过程，在客户需求与零售价线性相关、双方掌握完全信息的情况下，针对零售商的保留利润内生给定的特点，建立了收入共享契约框架下的Stackelberg博弈模型和数量折扣契约、两部费用契约下的契约参数优化模型；分析了契约的不同提供方、契约类型的选择和契约参数的优化对供应链整体绩效及利润在各方分配的影响；证明了当制造商所提供的产品具有高度可替代性时，实际增加了零售商的内生保留利润，即增强了零售商相对于制造商的议价能力，在这种情况下，制造商将更倾向于提供批发价契约而不是较为复杂的契约形式。最后通过数值仿真实验，分析验证了上述理论研究的结果。 2．构建了两阶段供应链、短视客户需求、不对称信息、产能约束条件下的混合契约优化模型。针对由单制造商和单零售商组成的双寡头垄断供应链、基于短视客户需求的报童模型、各方需求预测信息不对称的情况，建立了由预购契约和回购契约组成的改进型回购契约优化模型。通过该契约模型同时实现了协同预测、产能优化和供应链分销协调的目的。通过数值仿真实验，验证了改进型回购契约下的供应链协调。通过风险-利润边际和信息不对称度阐述了两段供应链无效性的原因。 3．建立了三阶段供应链、策略型需求、完全信息下的契约优化模型。在由制造商、零售商和理性客户组成的三阶段供应链结构中，根据理性客户及其对产品需求具有策略性的特点，基于零售商和客户间的理性预期均衡构建了研究策略型客户行为的模型框架。分析了集中式供应链绩效与批发价契约及价格补偿契约下分散式供应链绩效的关系，得出在这些契约协调下的策略型客户需求驱动型供应链分销渠道中，分散式供应链绩效严格优于集中式供应链绩效的创新性结论。 4．构建了基于SOA的契约自动协商平台。综合上述契约优化理论研究结论和已有的研究成果，抽象、封装了包含契约类型和契约参数的契约优化服务模型库。基于面向服务的体系架构（SOA）思想，运用数据挖掘软件Weka细化客户需求类型及供应链环境，采用Web Service技术封装各种契约服务，利用企业服务总线（ESB）提供各服务组件绑定、交互和管理通道，以及通过BPEL建模工具对各种服务进行符合逻辑的编排、重组和发布。通过所构建的契约协商平台，实现了供应链分销过程中契约协商的网络化、自动化、智能化和柔性化。

基于BPEL的工作流引擎的研究和实现

在企业大量地部署信息化系统之后，系统的弊端逐渐暴露，主要表现在：各系统建设在异构平台上，缺乏互操作性，形成信息孤岛；系统与工作流程粘度高，不能便捷的改变流程以满足市场快速变化的需要；系统间通信困难，难以有效地协调；不能同企业外的系统互通以增强企业间的业务联系。在现有的系统不能有效地满足企业需求的背景下，开发新的工作流系统来整合已有的信息系统，既可以满足企业的需求，又可避免浪费企业在信息化建设方面的投资，成为企业应用技术新的发展方向。 本文首先详细研究了早期工作流系统的特点和弊端，从业务人员和管理者的角度对信息系统提出新的功能要求；然后对当前主流的技术和标准进行研究分析，旨在寻找一种支持业务流程快速改变和部署、可跨平台通信、能有效地协调各信息系统的解决方案。在深入研究COM、CORBA、RMI、Web Service、BPEL等技术的基础之上，采用以Web Service为业务单元、应用BPEL语言将Web Service组合成为业务流程的方式作为解决方案。 在此基础上，本文根据软件分层思想，设计并实现了一个六层模式的BPEL引擎，并针对BPEL引擎的分层特点设计一套模块组合方案，可以根据需求扩展和替换其中的引擎组件。为更好地实现系统集成，本文对BPEL的端点引用机制做了修改和扩展，使其不仅能够集成默认的Web Service端点，还能直接集成系统中已有的流程和实现定义接口的子系统。同时深入研究面向服务的软件架构和企业服务总线技术，将引擎设计为插件软件，运行在满足JBI标准的企业服务总线上，进一步降低了BPEL引擎同其他系统的耦合性。 最后，以国内某家电公司的运营环境为背景，设计一套测试案例以检验BPEL引擎的功能完备性和性能可靠性；分析结果表明BPEL引擎满足用户的要求并具备一定的稳定性。