Browsing by Subject "Dynamic networks"
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Item Supporting device-to-device search and sharing of hyper-localized data(2015-05) Michel, Jonas Reinhardt; Julien, Christine, D. Sc.; Garg, Vijay; Lam, Simon; de Veciana, Gustavo; Vishwanath, SriramSupporting emerging mobile applications in densely populated environments requires connecting mobile users and their devices with the surrounding digital landscape. Specifically, the volume of digitally-available data in such computing spaces presents an imminent need for expressive mechanisms that enable humans and applications to share and search for relevant information within their digitally accessible physical surroundings. Device-to-device communications will play a critical role in facilitating transparent access to proximate digital resources. A wide variety of approaches exist that support device-to-device dissemination and query-driven data access. Very few, however, capitalize on the contextual history of the shared data itself to distribute additional data or to guide queries. This dissertation presents Gander, an application substrate and mobile middleware designed to ease the burden associated with creating applications that require support for sharing and searching of hyper-localized data in situ. Gander employs a novel trajectory-driven model of spatiotemporal provenance that enriches shared data with its contextual history -- annotations that capture data's geospatial and causal history across a lifetime of device-to-device propagation. We demonstrate the value of spatiotemporal data provenance as both a tool for improving ad hoc routing performance and for driving complex application behavior. This dissertation discusses the design and implementation of Gander's middleware model, which abstracts away tedious implementation details by enabling developers to write high-level rules that govern when, where, and how data is distributed and to execute expressive queries across proximate digital resources. We evaluate Gander within several simulated large-scale environments and one real-world deployment on the UT Austin campus. The goal of this research is to provide formal constructs realized within a software framework that ease the software engineering challenges encountered during the design and deployment of several applications in emerging mobile environments.Item Understanding query quality in dynamic networks(2010-08) Rajamani, Vasanth; Julien, Christine, D. Sc.; Perry, Dewayne; Batory, Don; Garg, Vijay; Bias, RandolphWith the proliferation of laptops, smart phones, sensors and other small devices, our physical environment is increasingly networked. Applications in a variety of problem domains (e.g., intelligent construction, traffic monitoring, smart homes, etc.) need to efficiently and seamlessly execute on top of such emerging infrastructure. Such infrastructure tends to be unreliable, and the network configuration changes constantly (network hosts depart and reemerge frequently). Consequently, software has to be able to react to these changes continuously and change its behaviors accordingly. In this dissertation, I introduce PAQ (Persistent Adaptive Query), a middleware designed to ease the programming burden associated with writing such applications. PAQ employs a novel style of query-driven application development that allows programmers to build pervasive applications by employing persistent queries--queries that continuously monitor the environment. The dissertation discusses the design and implementation of a new middleware model that allows programmers to write high level specifications abstracting away several tedious implementation details. PAQ employs both novel protocols that automatically tag the quality of information obtained from the network and statistical techniques to post-process and smooth the data. The goal of this research is to ease the software engineering challenges encountered during the construction and deployment of several applications in emerging pervasive computing environments thorough the use of a query-driven application development paradigm.