Distributed Object Technology In Mobile Computing Environment

Recent years have seen the rapid technical progress of wireless communications and increasing requirements of people to mobile applications. Owing to the dynamics, uncertainty and many limitations of mobile network environment, traditional distributed object technology (DOT), which plays an important role in many network applications, becomes awkward and even inapplicable in mobile scenarios. It's significant and valuable for both of researcher and engineer to investigate the DOT in mobile network environment.On the background of middleware, distributed object computing and mobile computing, the author explores the DOT in mobile environment at three levels, i.e., system kernel, application model and service. Some targets of the research works include the reflection technology, flexible distributed computing model, and resource discovery in mobile computing environment. Some innovative contributions of the dissertation are enumerated as:Proposing a general, abstract and theoretic reflective model, i.e., Information-Representation-Controlling model of Reflection. The distributed computing platform in mobile environment should be well customizable, adaptive, and context-aware, which is beyond the capabilities of traditional systems. A general and abstract theoretic model of reflection, namely, Information-Representation-Controlling of Reflection, is proposed to solve the problem. In this model, the information sub-model reveals some abstract facets in general systems, which can be reified by means of reflection, the representation sub-model decides how to represent the meta-information, while the controlling sub-model consists of some key elements to manipulate meta-level system, such as: meta-object protocol declaration, meta-object association and management. The reflection approaches based on the theoretic model are firstly used to solve several different kinds of key problems occurring in the core designing of mobile distributed object platform, i.e., context-awareness, communication adaptation, transparent object caching, remote replication of server objects. These approaches prove the wide applicability of the presented model, and show that the reflective systems are flexible, customizable, and scalable.Proposing a new dynamic deployment model based on mobile agents. Being familiar in the traditional client/server-based distributed applications, the mode that the computing resources are fixedly deployed in network is inclined to inefficient and even disabled in mobile environment. Aiming to the problem, a new dynamic deployment model based on mobile agents is proposed in the dissertation. The model of components coupling relationship, as a part of whole model, exposes the abstract application features of resource deployment and interaction. The autonomous and intelligent agent plays the role of component container, and on the other hand, it can adapt the resource deployment dynamically and purposefully, according to the features of application and currentnetwork status. To the applications following the model, the self-driven performance optimizing, load adjusting, and vibration restraining can be archived in mobile network environment. Comparing with the related works, the approach in this dissertation is active and general.Proposing a distributed method of resource discovery. In the mobile network, either resource providers or requesters are always moving and changing themselves. A distributed method of resource discovery is proposed in the dissertation, which is suitable to the different network scale and fluky resources. Two conceptual models, i.e., provider-directory-requester model and domain model, are foundation of the method. Some essentials of the models are analyzed subsequently. To the problem of global discovery among domains, a new multiple mobile agents cooperating system model based on fuzzy knowledge exchanging is proposed. The structure, life cycle and roaming strategy of mobile agent are involved in the mobil...