MADServer: An Architecture for Opportunistic Mobile Advanced Delivery

Rapid increases in cellular data traffic demand creative alternative delivery vectors for data. Despite the conceptual attractiveness of mobile data offloading, no concrete web server architectures integrate intelligent offloading in a production-ready and easily deployable manner without relying on vast infrastructural changes to carriers’ networks. Delay-tolerant networking technology offers the means to do just this. We introduce MADServer, a novel DTN-based architecture for mobile data offloading that splits web con- tent among multiple independent delivery vectors based on user and data context. It enables intelligent data offload- ing, caching, and querying solutions which can be incorporated in a manner that still satisfies user expectations for timely delivery. At the same time, it allows for users who have poor or expensive connections to the cellular network to leverage multi-hop opportunistic routing to send and receive data. We also present a preliminary implementation of MADServer and provide real-world performance evaluations

Flexible coordination techniques for dynamic cloud service collaboration

The provision of individual, but also composed services is central in cloud service provisioning. We describe a framework for the coordination of cloud services, based on a tuple‐space architecture which uses an ontology to describe the services. Current techniques for service collaboration offer limited scope for flexibility. They are based on statically describing and compositing services. With the open nature of the web and cloud services, the need for a more flexible, dynamic approach to service coordination becomes evident. In order to support open communities of service providers, there should be the option for these providers to offer and withdraw their services to/from the community. For this to be realised, there needs to be a degree of self‐organisation. Our techniques for coordination and service matching aim to achieve this through matching goal‐oriented service requests with providers that advertise their offerings dynamically. Scalability of the solution is a particular concern that will be evaluated in detail

The LighTS tuple space framework and its customization for context-aware applications

Our experience with using the tuple space abstraction in context-aware applications, evidenced that the traditional Linda matching semantics based on value equality are not appropriate for this domain, where queries often require the ability to match on value ranges, deal with uncertainty, and perform data aggregation. Originall

On component-oriented access control in lightweight virtualized server environments

2017 Fall.Includes bibliographical references.With the advancements in contemporary multi-core CPU architectures and increase in main memory capacity, it is now possible for a server operating system (OS), such as Linux, to handle a large number of concurrent services on a single server instance. Individual components of such services may run in different isolated runtime environments, such as chrooted jails or related forms of OS-level containers, and may need restricted access to system resources and the ability to share data and coordinate with each other in a regulated and secure manner. In this dissertation we describe our work on the access control framework for policy formulation, management, and enforcement that allows access to OS resources and also permits controlled data sharing and coordination for service components running in disjoint containerized environments within a single Linux OS server instance. The framework consists of two models and the policy formulation is based on the concept of policy classes for ease of administration and enforcement. The policy classes are managed and enforced through a Lightweight Policy Machine for Linux (LPM) that acts as the centralized reference monitor and provides a uniform interface for regulating access to system resources and requesting data and control objects. We present the details of our framework and also discuss the preliminary implementation and evaluation to demonstrate the feasibility of our approach

Automata-based Optimization of Interaction Protocols for Scalable Multicore Platforms (Technical Report)

Multicore platforms offer the opportunity for utilizing massively parallel resources. However, programming them is challenging. We need good compilers that optimize commonly occurring synchronization/interaction patterns. To facilitate optimization, a programming language must convey what needs to be done in a form that leaves a considerably large decision space on how to do it for the compiler/run-time system. Reo is a coordination-inspired model of concurrency that allows compositional construction of interaction protocols as declarative specifications. This form of protocol programming specifies only what needs to be done and leaves virtually all how-decisions involved in obtaining a concrete implementation for the compiler and the run-time system to make, thereby maximizing the potential opportunities for optimization. In contrast, the imperative form of protocol specification in conventional concurrent programming languages, generally, restrict implementation choices (and thereby hamper optimization) due to overspecification. In this paper, we use the Constraint Automata semantics of Reo protocols as the formal basis for our optimizations. We optimize a generalization of the producer-consumer pattern, by applying CA transformations and prove the correctness of the transforms

Methods of implementation of context-aware platforms and context-aware user interfaces for applications in consumer electronics

U okviru disertacije predstavljene su metode realizacije kontekstualnih platformi i kontekstualnih korisničkih sprega za uređaje potrošačke elektronike. Predloženi su algoritmi semantizacije konteksta i procene zauzetosti korisnika, arhitektura rešenja i rezultati evaluacije.  In this dissertation methods of implementation of context-aware platforms and context-aware user interfaces for applications in consumer electronics are presented. The work includes the proposition of algorithms for context semantization and user availability estimation, architecture of the solution as well as the results of evaluation experiments