【作者】 刘厚泉；

【导师】 谭海樵；

【作者基本信息】 中国矿业大学 ， 地球探测与信息技术， 2009， 博士

【摘要】 任务模型不仅包含了对上下文管理的知识,更重要的是包含了解决实际问题的知识。由于移动位置服务涉及复杂的上下文要素,用户的任务目标也会中途发生改变,因此现有的移动位置服务的任务建模仍无法满足任务目标多样性、任务信息共享性、任务操作高效性方面的需求。在分析移动位置服务任务模型特点的基础上,提出了一个动态任务模型结构DAMo,它对现有的任务模型进行了两方面的改造:一是增强任务模型对动态多任务的描述能力,二是增强任务模型对信息传递的描述能力。该模型包含3个方面的概念:(1)任务类型,DAMo通过任务类型描述一类任务的属性和实现任务的方法;(2)任务操作,DAMo包含插入(insert)、替换(replace)、接续(link)、合并(unify)和暂停(suspend)5种任务操作方式,它们用于描述多任务之间的依赖关系;(3)任务通道,DAMo模型通过任务通道描述任务操作时信息传递的情况。每一类操作对应一种类型的任务通道,它们描述了参加操作的任务之间属性的数值依赖关系。使用这些概念,可以方便地描述任务的动态变化、任务的组合和任务之间的信息交互。为了提高DAMo运行时的效率,采用扩展元组空间作为移动位置服务中间件的信息交互模式。元组空间作为一种分布式通信机制,具有处理异构、异步和松耦合信息交互的能力。由于传统的元组空间概念过于简单,在使用中常常需要针对特殊的要求加以扩展。ChaSpace是一个扩展元组空间,它在元组空间中引入了交互通道的概念。通道是一个点对点的通信媒体,它具有特定的标识和两个不同的交互终端。通道可以在协同系统中作为独立的通信机构,保障协同系统的通信在时间、空间方面的非耦合性。将元组空间模型与通道模型相结合,形成一个独特的协同交互模型,主要特点是既具有元组空间的信息共享性,又具有通道的可控性。它通过元组模板、过滤规则和触发规则,对DAMo的信息交互方式提供直接的支持。通过使用DAMo对一个博物馆数字导游系统任务模型的描述,证明了DAMo可以有效地描述移动位置服务中多任务操作时信息的交互情况。更多还原

【Abstract】 In task model there is not only the knowledge on management of context but also the knowledge on solutions of practical problems. Current task modeling of LBS is still unable to meet the requirements on diversity of objectives, sharing of information and efficiency of operations as the complex context elements are always involved in LBS and the objective in task could be changed under way.A framework of dynamic task model, named DAMo, is proposed in the thesis based on an analysis of characteristics in task model of LBS. In DAMo there are two aspects of improvement for existing task model, one is to enhance description capability of task model on dynamic multi-tasks and the other is to improve description capability of task model on information transmission. Three concepts are applied in the DAMo model. (1) Task type: Descriptions of task attributes and approach to implement it. (2) Task operations: Descriptions of the relationship in multi-tasks, including as insert, replace, link, unify and suspend. (3) Task channel: Descriptions of information transmission. Each type of operation corresponds to a kind of channel, which describes the interrelation of attribute values of tasks that participate in the operations. It is convenient to describe the dynamic changing, composition, and information interaction of task using the three concepts mentioned above.To improve the running efficiency of DAMo, the extended tuple space is adopted as the mode of information interaction in the middleware of LBS. As a distributed communication mechanism, the tuple space is capable to process heterogeneous, asynchronous and loosely coupled information interaction. It always needs to extend the concept of tuple space for special requirements in applications as the traditional concepts are too simple. The concept of interactive channel is introduced in ChaSpace which is an extended tuple space. The channel is a point-to-point communication media which has a specific ID and two different interactive terminals. A channel can act as an independent communication agent in collaborative system to ensure the non-coupling of time and space in communication. The combination of tuple space and channel model will make up a unique collaborative interactive model, which can be used for both the information sharing of tuple space and the operation controlling of channel. The model provides direct support for information interaction in DAMo through tuple template, filtering rule and triggering rule. In a case study, DAMo is employed in describing task model of a digital museum guide system. Research results demonstrate that DAMo can be used to effectively describe information interaction in multi-tasks of LBS.更多还原