Interprocedural Data Flow Analysis in Soot using Value Contexts

An interprocedural analysis is precise if it is flow sensitive and fully context-sensitive even in the presence of recursion. Many methods of interprocedural analysis sacrifice precision for scalability while some are precise but limited to only a certain class of problems. Soot currently supports interprocedural analysis of Java programs using graph reachability. However, this approach is restricted to IFDS/IDE problems, and is not suitable for general data flow frameworks such as heap reference analysis and points-to analysis which have non-distributive flow functions. We describe a general-purpose interprocedural analysis framework for Soot using data flow values for context-sensitivity. This framework is not restricted to problems with distributive flow functions, although the lattice must be finite. It combines the key ideas of the tabulation method of the functional approach and the technique of value-based termination of call string construction. The efficiency and precision of interprocedural analyses is heavily affected by the precision of the underlying call graph. This is especially important for object-oriented languages like Java where virtual method invocations cause an explosion of spurious call edges if the call graph is constructed naively. We have instantiated our framework with a flow and context-sensitive points-to analysis in Soot, which enables the construction of call graphs that are far more precise than those constructed by Soot's SPARK engine.Comment: SOAP 2013 Final Versio

Dissecting Tumor Heterogeneity in Lung Cancer

Lung cancer is a heterogeneous disease composed of genetically and phenotypically distinct tumor cells as well as a heterogeneous microenvironment consisting of non-cancer cells and extracellular matrix. Constant interactions among these components ultimately leads to a complex tumor tissue that is ever evolving and poses a therapeutic challenge for sustained benefit. Strategies for targeting lung cancers are largely guided by the genetic alterations identified in the tumor specimens. However, in order to gain a better understanding of lung cancer progression and develop effective treatment modalities, studying tumor in context of its microenvironment is crucial. The first aim of this project was to establish an experimental model to capture tumor heterogeneity. We developed an Ex Vivo Tumor system that preserved tumor composition and allowed the introduction of specific modifications in the tumor microenvironment to investigate their role in tumor progression. We utilized this system to demonstrate the role of extrinsic as well as intrinsic alterations that modify tumor cell behavior. Next, we explored the biological phenomenon epithelial-to-mesenchymal transition as a source of tumor cell heterogeneity and therapeutic resistance. Genetically identical KRAS mutant lung cancer cells displayed different phenotypic states that were associated with distinct survival pathways that allowed cancer cells to escape therapeutic targeting. With the use of extensive in vitro, ex vivo and in vivo models, we identified that a combinatorial approach of utilizing CDK4 and MEK inhibitors to effectively control tumor growth by targeting distinct tumor subpopulations within lung cancer and prevented emergent resistance to either single agent

Coordinating Heterogeneous Web Services through Handhelds using SyD’s Wrapper Framework

Tying web services together to build large, distributed, collaborative applications has gathered noticeable momentum and a lot of research is being put in it. Along with composition of the web services, coordination is one key aspect that has been considered keenly. Many frameworks, languages and protocols have been proposed for web service composition and coordination. With the advancement in wireless technology and rapid deployment of mobile services, collaborative application development for small devices using such composed web services finds a new research area. Much less work has been done in the area of web service coordination for mobile environment. In this thesis, we propose a new distributed approach in service composition and coordination and show that our approach works well in an environment containing mobile heterogeneous devices. We discuss a novel approach of SyD (System on Devices)wrapper framework for dynamically creating and executing web bonds among various heterogeneous web services. The wrapper is a lightweight SyD application object that encapsulates composition and coordination logic and provides higher level of coordination among bonded entities. The wrapper framework gives small devices full capability to run distributed collaborative applications that use heterogeneous web services. We have also developed and analyzed experiments to showcase the performance of SyD Wrapper Framework

Don't mind the gap: Bridging network-wide objectives and device-level configurations

We reflect on the historical context that lead to Propane, a high-level language and compiler to help network operators bridge the gap between network-wide routing objectives and low-level configurations of devices that run complex, distributed protocols. We also highlight the primary contributions that Propane made to the networking literature and describe ongoing challenges. We conclude with an important lesson learned from the experience

A New Phenomenon: Sub-Tg, Solid-State, Plasticity-Induced Bonding in Polymers

Polymer self-adhesion due to the interdiffusion of macromolecules has been an active area of research for several decades [70, 43, 62, 42, 72, 73, 41]. Here, we report a new phenomenon of sub-Tg, solid-state, plasticity-induced bonding; where amorphous polymeric films were bonded together in a period of time on the order of a second in the solid-state at ambient temperatures nearly 60 K below their glass transition temperature (Tg) by subjecting them to active plastic deformation. Despite the glassy regime, the bulk plastic deformation triggered the requisite molecular mobility of the polymer chains, causing interpenetration across the interfaces held in contact. Quantitative levels of adhesion and the morphologies of the fractured interfaces validated the sub-Tg, plasticity-induced, molecular mobilization causing bonding. No-bonding outcomes (i) during the compression of films in a near hydrostatic setting (which inhibited plastic flow) and (ii) between an 'elastic' and a 'plastic' film further established the explicit role of plastic deformation in this newly reported sub-Tg solid-state bonding