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Ph.D. Theses

Dynamic Management of Network Systems

By Syed Yousaf Shah
Advisor: Boleslaw Szymanski
October 20, 2014

Networks are becoming integral part of our lives. Services hosted on our mobile devices, network hubs and networked servers provide us with functionalities that were never so ubiquitous in our lives. These services are customized to our needs and requirements more than ever by providing us with the intelligence and support that we need. Researchers from both academia and industry are innovating cutting edge technologies and services to take advantage of the smart networked devices. The smart phones, tablets and other mobile and sensing devices offer lots of functionalities along with various challenges. These challenges span over various aspects i.e., from morphology of these networked devices to the mobility pattern of these devices and from policy enforcing data shared by these devices to the data transport protocols and congestion control mechanisms.

With growing ubiquity of mobile devices the next generation service oriented systems face various challenges due to increasing number of services involved in each system and volume of data produced by them. This thesis focuses on three challenges, (1) How to efficiently manage resources such as network routes, among multi-priority applications in resource-constrained scenarios, such as congestion, to reduce the loss of Quality of Information (QoI); (2) how to configure and compose services that produce information which is relevant to the users interest? (3) How to share network resources efficiently by mapping human readable policies to low-level system constraints.

For the first challenge, this thesis explores pricing mechanism for route allocation in event-driven scenarios. Multi-priority traffic suffers from loss of QoI in event-driven scenarios. Such scenarios trigger bursts of data when an event happens, e.g., sensor nodes tracking a target. We present how to utilize pricing mechanism in routing and show that by dynamically pricing the network routes, they can be efficiently assigned to multi-priority traffic to avoid congestion thus lowering the overall QoI losses.

Sensor Networks, mobile devices and online services are producing huge amount of data these days. From plethora of these data sources, fusing data from most relevant sources to produce information that is relevant to the users interest is a challenging task. Thus, this thesis also explores how can we dynamically compose complex sensor services that produce information spatially relevant to the users interest? We present three models to capture the concept of relevancy in composite services and present the design of a service-oriented system that uses these models to compose complex services from services hosted on sensor nodes, conforming to operational and spatial constraints.

In the last part of this thesis, we present a policy enforcement mechanism that enables resource sharing among multiple parties in a shared network infrastructure. We explore how to enable end-users and policy makers to use human readable formats for sys- tem management and transparently transform human understandable policies to machine- level hard and soft constraints for application configuration. We present a set language based approach to produce restricted set of resources for executable application configuration of a user request based on declared policies and user.s privileges.

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