Computation and networking resources in mobile operating environments are much scarcer and more dynamic than in desktop operating environments. Mobile applications can leverage on the benefits of adaptive computing to optimize the QoS delivery based on contextual situations. Fuzzy control models have been successfully applied to various distributed network QoS management systems. However, existing models are either application-specific or limited to abstract modeling and simple conceptual scenarios which do not take into account overall model scalability. Specifically, the large number of QoS parameters in a mobile operating environment causes an exponential increase in the number of rules correspondingly increases the demand for processing power to infer the rules. Hierarchical fuzzy systems were introduced to reduce the number of rules using hierarchical fuzzy control, in which correlated linguistic variables are hierarchically inferred and grouped into abstract linguistic variables. In this paper, we propose a mobile QoS management framework that uses a hierarchical fuzzy control model to support a highly extensible and structured adaptation paradigm. The proposed framework integrates several levels of QoS abstractions derived from user-perceived requirements.

Computation and networking resources in mobile operating environments are much scarcer and more dynamic than in desktop operating environments. Mobile applications require the benefits of adaptive computing to optimize the QoS management of dynamic contextual situations. Fuzzy control models have been successfully applied to various distributed network QoS managements systems. However, these models are either application-specific or limited to abstract modeling and simple conceptual scenarios that do not take into account overall model scalability. Specifically, the large number of QoS parameters in mobile operating environment causes the rule-explosion problem, in which an exponential increase in the number of rules increases the demand for processing power to infer the rules. Hierarchical fuzzy systems were introduced to reduce the number of rules using hierarchical fuzzy control, in which correlated linguistic variables are hierarchically inferred and grouped into abstract linguistic variables which can then be used as input for higher level fuzzy rules. In this paper, we propose a mobile QoS management framework that uses a hierarchical fuzzy control model to support a highly extensible and uncomplicated adaptation paradigm. This framework makes use of the synergy between mobile operating environments, mobile services and mobile applications, produces optimal system performance and satisfies the QoS needs of individual mobile applications.

The formulation of a context-aware middleware requires researchers to devise suitable control mechanisms that allow applications to directly participate in resource adaptation in response to dynamic operating environments. This paper describes the design and implementation of an event model for a highly adaptive mobile middleware, Web Proxy for Actively Deployable Services (WebPADS) platform. The event model provides a highly composable event notification framework that uses multiple levels of environment monitors to provide a complex setup of composite events. Based on the event model and the dynamic reconfiguration feature WebPADS supports context awareness and a high level of adaptation to contextual changes through reconfiguration and migration of services.

This paper describes a dynamic service reconfiguration model where the proxy is composed of a chain of service objects called mobilets (pronounced as mo-be-lets), which can be deployed onto the network actively. This model offers flexibility because the chain of mobilets can be dynamically reconfigured to adapt to the vigorous changes in the characteristics of the wireless environment, without interrupting the service provision for other mobile nodes. Furthermore, mobilets can also be migrated to a new proxy server when the mobile node moves to a different network domain. We have realized the dynamic service reconfiguration model by crafting its design into a programmable infrastructure that forms the baseline architecture of the WebPADS (short for Web Proxy for Actively Deployable Services) system.

Traditionally, middleware technologies, such as CORBA, Java RMI, and Microsoft's DCOM, have provided a set of distributed computing services that essentially abstract the underlying network services to a monolithic "black box." In a mobile operating environment, the fundamental assumption of middleware abstracting a unified distributed service for all types of applications operating over a static network infrastructure is no longer valid. In particular, mobile applications are not able to leverage the benefits of adaptive computing to optimize its computation based on current contextual situations. In this paper, we introduce the Mobile Platform for Actively Deployable Service (MobiPADS) system. MobiPADS is designed to support context-aware processing by providing an executing platform to enable active service deployment and reconfiguration of the service composition in response to environments of varying contexts. Unlike most mobile middleware, MobiPADS supports dynamic adaptation at both the middleware and application layers to provide flexible configuration of resources to optimize the operations of mobile applications. Within the MobiPADS system, services (known as mobilets) are configured as chained service objects to provide augmented services to the underlying mobile applications so as to alleviate the adverse conditions of a wireless environment.

Describes a Web proxy architecture called WebPADS, short for "Web Proxy for actively deployable services." The RebPADS was developed to enhance Web applications running on a wireless network. The RebPADS provides mechanisms to automatically locate and configure a flexible and adaptive wireless Web proxy. In addition, it provides a framework that facilitates the development of add-on services, where the services can be actively deployed and migrated across Web proxies, in order to adapt to the changing wireless environment.

This paper describes a Web proxy architecture called WebPADS, which is in short for "Web proxy for actively deployable services". WebPADS is developed to enhance Web applications running on wireless networks. WebPADS provides mechanisms that automatically locate and configure a flexible and adaptive wireless Web proxy. In addition, it provides a framework that facilitates the development of add-on services, which can be actively deployed and migrated across Web proxies, in order to adapt to the changing wireless environment.