【作者】 王睿；

【导师】 曾广周；

【作者基本信息】 山东大学 ， 计算机应用技术， 2009， 博士

【摘要】 迁移工作流(Migrating Workflow)是将移动agent计算模式应用于工作流管理的一门新技术。与传统的工作流模型不同,迁移工作流是一个或多个迁移实例(Migrating Instance)在不同工作位置(Work Place)之间不断迁移并就地利用工作位置服务执行业务活动的过程,其中,迁移实例是工作流活动的主体,工作位置是工作流联盟成员服务在网络上的节点映射。工作流联盟上所有工作位置的集合称作迁移工作流环境,为了与本文研究相区别,文中称为单工作位置环境。目前的迁移工作流研究主要采用面向过程的方法,即令迁移实例携带业务过程说明书工作。业务过程说明书中固有的结构化属性,不可避免地会限制迁移实例求解问题的灵活性,降低其对环境动态变化的适应性。为了克服面向过程的迁移工作流方法的不足,在面向目标的迁移工作流模型中,迁移实例携带工作流目标说明书工作。工作流目标既可以通过迁移实例自身的服务发现实现,也可以通过工作位置的服务推荐实现(本文称工作位置对迁移实例的工作位置导航和工作流资源推荐为迁移工作流主动服务)。当工作流目标可以分解为多个业务子目标时,对于并行的业务子目标,不同的迁移实例可以在不同的工作位置上生成并首先在该工作位置运行。因为面向目标的迁移工作流可以大大提高迁移实例对工作环境动态变化的适应性,因此特别适合那些活动及其转移规则难于完全定义的跨机构业务过程。本文针对单工作位置环境上主动服务能力不足的问题,在国家自然科学基金项目的资助下,以曾广周教授提出的迁移工作流系统框架为基础,研究了一类面向目标的迁移工作流主动服务方法,包括:基于业务熟人域的迁移工作流主动服务环境构建方法,业务熟人域上面向目标的迁移实例导航服务方法,业务熟人域上面向目标的迁移工作流资源服务推荐方法,业务熟人域上多服务主体收益分配方法,并通过实验对研究成果进行了验证和分析。本文的主要工作包括:1.面向目标的迁移工作流主动服务环境构建方法研究。针对单工作位置环境上主动服务能力不足的问题,本文借鉴人类社会中的“小世界现象”,提出了一种基于业务熟人域的迁移工作流主动服务环境构建方法。方法的基本思想是:首先依据成员合作关系的类型和性质,将工作流联盟上的成员划分为面向目标的“小世界”(称为业务熟人域)集合;然后通过业务熟人域之间的成员合作关系,将工作流联盟上的成员集合映射为一个业务熟人网络,该业务熟人网络即为面向目标的迁移工作流主动服务环境。文中重点讨论了业务熟人域的可构造性质,给出了业务熟人域的构造算法和演化策略。实验表明,基于业务熟人域为迁移实例提供主动服务,较之单工作位置服务有更高的服务能力。2.面向目标的迁移工作流服务导航方法研究。在面向目标的迁移工作流模型中,服务导航是指当前工作位置向迁移实例推荐下一个合适的工作位置,工作位置上的导航主体既可以有全局工作流视图,也可以没有全局工作流视图。本文只研究导航主体缺少全局工作流视图的情况,因此,对服务导航方法的最低要求是不能造成迁移实例迷航而使迁移工作流中断。针对业务熟人域上导航主体缺少全局工作流视图的问题,本文视业务熟人域为当前导航主体部分可观测的工作流环境,采用POMDP方法,提出了一种基于业务熟人域的服务导航模型,定义了目标关联策略描述规范,给出了服务导航索的生成算法和目标驱动的服务导航算法。实验表明,基于业务熟人网进行服务导航,可以有效避免迁移实例迷航,并具有较高的导航效率和导航可靠性。3.面向目标的迁移工作流资源服务推荐方法研究。在面向目标的迁移工作流模型中,工作流资源服务推荐是指王作位置向迁移实例推荐那些能够满足工作流目标的数据、程序、工具和用户,以帮助迁移实例高效地完成那些需要在本地执行的任务。如果工作位置上的工作流资源服务能力受限,轻则会影响工作流进程的速度,重则会造成工作流进程停滞。针对单工作位置上资源服务能力不足的问题,本文建立了一种基于业务熟人域的多主体工作流资源服务推荐方法。为了快速实现成员间的资源服务分担,本文重点研究了成员发现和群组织中的通信协议问题。实验表明,本文建立的通信协议,可以有效提高基于业务熟人域的多主体资源服务推荐效率,具有很好的服务可靠性。4.面向目标的迁移工作流多服务主体收益分配方法研究。业务熟人域上的迁移工作流主动服务,本质上是一种多主体联合主动服务。为了保证多主体之间的稳定合作,本文针对现有研究成果中收益分配策略对收益补偿评估的不足,提出了一种基于动态合作博弈的多主体收益分配策略。策略的基本思想是:将多主体收益分配问题形式化为一个多人动态合作博弈,通过寻求动态合作博弈中马尔可夫完美均衡计算多主体的收益补偿,并利用补偿协调多服务主体最优收益分配。文中定义了多主体共识原则,给出了业务熟人域上的收益分配算法。实验表明,本文提出的收益分配策略能够使多服务主体根据最优共识原则,分配各方的合作收益,从而达到多赢的帕累托最优局面。本文工作的创新点主要体现在:1.针对单工作位置环境主动服务能力不足的问题,提出了一种基于业务熟人域的迁移工作流主动服务环境模型。业务熟人域是工作流联盟成员集合上面向服务目标的成员子集,其“小世界”性质使得业务熟人域容易构造和演化。由业务熟人域互连而成的业务熟人网络,覆盖工作流联盟上的所有成员和服务,因而可以保证迁移实例有一个目标可达的动态工作环境。与单工作位置环境相比,业务熟人域上不仅蕴含了更强的多主体联合服务能力,而且可以使迁移实例在同一个业务熟人域上就近尽可能地完成多个工作流子目标,从而提高执行效率。2.针对业务熟人域上服务主体缺少全局工作流视图的问题,提出了一种部分可观测环境下的迁移工作流服务导航方法。在面向目标的迁移工作流模型中,业务熟人域上的工作流视图是导航主体唯一可见的局部工作流视图,或称作导航主体部分可观测的迁移工作流环境。与基于全局工作流视图的服务导航模型和算法相比,本文建立的部分可观测环境下的迁移工作流服务导航方法,不仅可以使工作流设计者摆脱全局工作流视图难以完善定义的困境,而且能够使迁移实例尽可能地在业务熟人域上迁移和就地工作,因而既可以有效规避迷航风险,也可以提高工作流效率。3.针对业务熟人域上的合作稳定性问题,提出了基于动态合作博弈的多主体收益分配策略。业务熟人域上的服务主体都是理性的工作流参与者,他们在追求工作流全局目标的同时,必定关注自己的收益,因此,合理的收益分配是保持业务熟人域稳定的基础。与现有研究成果中的收益分配策略相比,本文提出的基于动态合作博弈的多主体收益分配策略,弥补了现有策略对收益补偿评估的不足,实现了服务主体收益的最优化分配,因而有利于保持业务熟人域上的合作稳定性。本文进一步的工作包括:建立业务熟人网络的演化策略,用以支持主动服务异常的处理与故障恢复,提高迁移工作流的可达性和可靠性;建立业务熟人域上协同导航索的趋同性生成方法,用以消除多导航主体之间存在的导航意图和导航方法差异,提高业务熟人域上联合服务导航的健壮性和效率。更多还原

【Abstract】 Migrating workflow is an emerging technology that applies the mobile-agent computing paradigm to workflow management. Different from the traditional workflow model, migrating workflow is a process in which one or more migrating instances migrate continuously and utilize local workflow service to execute their tasks. Migrating instance is a performing agent of tasks. Work place is mapped to the network node, which is one of workflow participants. The set of all work places is called as migrating workflow environment in the workflow alliance, which is called the single work place environment in this thesis. Research in the field of process-oriented migrating workflows has primarily focused on workflow specifications. However, inherent structurized attributes in workflow specifications will limit the flexibility of migrating instances to solve questions inevitably, and reduce the compatibility to the dynamic environment.In order to overcome the shortage of workflow process-oriented approach, migrating instances run with workflow specifications in the goal-oriented migrating workflow. The migrating workflow goal is realized by migrating instace’s service discovery or work place’s service recommendation (Migrating instances are recommend with work place and workflow resource is called migrating workflow active service in this thesis). A complex business goal is composed by a number of sub-goals. For different business processes goals, different migrating instances generat and run in the work place. Therefore, goal-oriented migrating workflow improves workflow system’s flexibility to adapt to dynamic environment, especially for the concurrent distributed business processes.This study was mainly supported by the National Natural Science Foundation of China under Grant and based on the migrating workflow framework proposed by professor ZENG This thesis focused on the methods of goal-oriented migrating workflow active service: a conformation method of the goal-oriented migrating workflow service environment based on business acquaintance domain, a migrating instance service navigation method for goal-oriented migrating workflow, a resource service recommendation method for goal-oriented migrating workflow and a profit allocation method of multi-service-agent for goal-oriented migrating workflow. The study has also built experiments to validate the conclusions.The main contributions of this thesis are described as follows:1. A conformation method of active service environment for goal-oriented migrating workflows.Aiming at the question of insufficient active service ability of single "work place, this thesis borrowed the "small world phenomenon" of the social groups and provided the method of constructing the active service environment for workflows. The basic idea of this method is: Firstly, based on the member cooperation’s type and the nature, members of migrating workflow will be divide into the goal-oriented "small world"sets (called service acquaintance domain); Then through the members of service acquaintance domains cooperating, the workflow member sets will be mapped as a service acquaintance network, which is called as active service environment for goal-oriented migrating workflow. In this thesis, we discussed the nature of service acquaintance domain, gave the strategy of construction and evolvement of acquaintance domain. Moreover, the experiments indicated that the active service based on the business acquaintance domain has the higher service ability than sigle work place.2. A service navigation method for goal-oriented migrating workflows.Service navigation means the current work place recommend the next work place for migrating instance. The navigation agent in the work place has a full or part workflow view. This thesis only studied on the navigation agent lacking of full workflow view. In order to meet the rich of services for the goal-oriented migrating workflow, we established POMDP method. This thesis proposed a service navigation model with the business acquaintance mechanism in partially observable environment, analysed service actors to meet the users, gave a service navigation strategy and proposed the arithmetic to build a service navigation cable. The experiment indicated that the sevice navigation based on service acquaintance domain did not enable migrating instance to get lost.3. A resource service recommendation method for goal-oriented migrating workflows.In goal-oriented migrating workflows model, resource service recommendation means the workflow resources such as data, procedures, tools and users, which are satisfied with the workflow goal, are recommendated to migrating instances by work places. If workflow resource services are limited, the workflow speed will be affected or stagnated. Aiming at the question which resource service is insufficient in single work place, this thesis provided a method of the resource service recommendation based on muliti-service agents for goal-oriented migrating workflows. In order to realize resource services were shared between members, we studied the member discovery and the group organization’s communication protocol. The experiment indicated that the communication protocol enhanced resource service recommendation efficiency and reliability effectively.4. A profit allocation method of multi-service agents for goal-oriented migrating workflows.Active service based on the business acquaintance is one kind of multiagent union to active service essentially in migrating workflows. In order to guarantee the stable cooperationIn between the multiagents, this thesis studied the stratgy of multi-service agents profit allocation. The basic idea of this stratgy is that multi-service agents allocate profit for a business service net is formulated as a dynamic cooperative game. Though finding Markov perfect equilibrium solution of the dynamic cooperative game, corresponding compensation was computed. Using this compensation information, a profit allocation algorithm was designed. The results of the experiments showed that the profit allocation algorithm could achieve a multi-win Pareto-Optimal outcome, which makes active service tending to be more stable.The main innovative contributions of this thesis are:1. Aiming at the question of insufficient active service ability of single work place, a conformation method of active service environment based on the business acquaintance domain for goal-oriented migrating workflows was proposed.The service acquaintance domain is a goal-oriened member subset of workflow alliance, which is builted and evolved according to the "small world" nature. Service acquaintance network which are interconnected by the service acquaintance domains cover all members and services of workflow alliance. Service acquaintance network may guarantee that the migrating instance has the dynamic work environment which the goal may reach. Compares with the single work place environment, service acquaintance domain not only has stronger multiagent union service ability, but also enhances the efficiency of workflows.2. Aiming at the question that service agent of business acquaintance domain has part workflow view, a service navigation method in partially observable environment for migrating workflows was proposed.In the goal-oriented workflow model, the workflow view of service acquaintance domain is the navigation agent can only observe partial workflow view, which is called as partially observe environment. Comparing with service navigation model and the algorithm based on the overall workflow view, the navigation method in partially observe environment could not only reduce the design difficulty of the multi-organizations and the large-scale workflow management system effectively, but also enhance the efficiency of workflows.3. Aiming at the question of the cooperative stability of service acquaintance domain, a strategy of multi-service agents profit allocation for goal-oriented migrating workflows was proposed.Service agents in the service acquaintance domain are rational workflow participants. They are pay attention to their profit while pursuing the workflow global goal. Therefore, the reasonable profit allocation is a foundation to maintain the service acquaintance domain stable. Comparing with the existing research results, this thesis proposed the strategy of multi-service agents profit allocation based on the dynamic cooperation game, which had made up the existing strategy. The strategy realized the optimized profit assignment among service agents and keeped the cooperation stability of service acquaintance domainThe author proposes the following future works: The service acquaintance network’s evolved strategy will be established to support unusual processes and breakdown restores, which enhances the accessibility and the reliability of migrating workflows. Build a method of navigation cable based on service acquaintance domain to eliminate the recommendation difference between navigaition goal and method, which will improve the toughness and the efficiency of service navigation.更多还原