Efficient network camouflaging in wireless networks

Camouflaging is about making something invisible or less visible. Network camouflaging is about hiding certain traffic information (e.g. traffic pattern, traffic flow identity, etc.) from internal and external eavesdroppers such that important information cannot be deduced from it for malicious use. It is one of the most challenging security requirements to meet in computer networks. Existing camouflaging techniques such as traffic padding, MIX-net, etc., incur significant performance degradation when protected networks are wireless networks, such as sensor networks and mobile ad hoc networks. The reason is that wireless networks are typically subject to resource constraints (e.g. bandwidth, power supply) and possess some unique characteristics (e.g. broadcast, node mobility) that traditional wired networks do not possess. This necessitates developing new techniques that take account of properties of wireless networks and are able to achieve a good balance between performance and security. In this three-part dissertation we investigate techniques for providing network camouflaging services in wireless networks. In the first part, we address a specific problem in a hierarchical multi-task sensor network, i.e. hiding the links between observable traffic patterns and user interests. To solve the problem, a temporally constant traffic pattern, called cover traffic pattern, is needed. We describe two traf- fic padding schemes that implement the cover traffic pattern and provide algorithms for achieving the optimal energy efficiencies with each scheme. In the second part, we explore the design of a MIX-net based anonymity system in mobile ad hoc networks. The objective is to hide the source-destination relationship with respect to each connection. We survey existing MIX route determination algorithms that do not account for dynamic network topology changes, which may result in high packet loss rate and large packet latency. We then introduce adaptive algorithms to overcome this problem. In the third part, we explore the notion of providing anonymity support at MAC layer in wireless networks, which employs the broadcast property of wireless transmission. We design an IEEE 802.11-compliant MAC protocol that provides receiver anonymity for unicast frames and offers better reliability than pure broadcast protocol

Trends in Data Locality Abstractions for HPC Systems

The cost of data movement has always been an important concern in high performance computing (HPC) systems. It has now become the dominant factor in terms of both energy consumption and performance. Support for expression of data locality has been explored in the past, but those efforts have had only modest success in being adopted in HPC applications for various reasons. them However, with the increasing complexity of the memory hierarchy and higher parallelism in emerging HPC systems, locality management has acquired a new urgency. Developers can no longer limit themselves to low-level solutions and ignore the potential for productivity and performance portability obtained by using locality abstractions. Fortunately, the trend emerging in recent literature on the topic alleviates many of the concerns that got in the way of their adoption by application developers. Data locality abstractions are available in the forms of libraries, data structures, languages and runtime systems; a common theme is increasing productivity without sacrificing performance. This paper examines these trends and identifies commonalities that can combine various locality concepts to develop a comprehensive approach to expressing and managing data locality on future large-scale high-performance computing systems

Choreographies of Community: Familias and its impact in the South Bronx

This thesis documents the creation, performance, and reception of Familias, a performance project created in 1994-95 by visual artist Pepón Osorio and choreographer Merián Soto, both in and out of its generative South Bronx context. This strategic close reading explores and presents Familias as an exemplar and richly instructive instance of socially engaged, community-based art making. By exploring Familias through multiple points of access – how it dances, speaks, listens and is understood / misunderstood -- this thesis reveals other narratives and paradigms for thinking about the work and its participants, and by extension, further engages with the creative process and production possibilities in the South Bronx. Reviewing Familias further with a curatorial perspective reveals opportunities that could strengthen other current art and community projects. In other words, by thinking about how Familias activates, generates, and replenishes itself in its creative process, this thesis also helps reconfigure how we can think about other possibilities in the borough. Chapter breakdown: “Bronx Renaissance” examines structural underpinnings of long-term economic depression in the borough and offers multivalent arguments for change. “Familias and the South Bronx” offers further historical background that situates Familias locally, and provides insights into the artistic visions and curatorial work of its lead artists. “Pepatián and the South Bronx” offers insights into my own practice, and how my experiences and creative grappling with the making of Familias, together with my sustained participation and leadership of alternative art making circuits in the South Bronx, led to the creation of a performance piece: How I Became a Boogie-Down Rican. “Familias” provides four distinct perspectives into the work with interludes to further underscore the impact of performing arts and organizations in the borough. This writing approach with performance and curatorial work as research-site offers material far beyond existing reviews, articles and video documentation. “How I Became a Boogie-Down Rican” explores the performance work of an experientially informed, next-level socially engaged, community-based practice from my experiences in the borough. An engagement with Familias shows how the artists’ work and their way of working offer a local legacy of impact that continues to inspire

Exploiting Mobile Social Networks from Temporal Perspective:A Survey

With the popularity of smart mobile devices, information exchange between users has become more and more frequent, and Mobile Social Networks (MSNs) have attracted significant attention in many research areas. Nowadays, discovering social relationships among people, as well as detecting the evolution of community have become hotly discussed topics in MSNs. One of the major features of MSNs is that the network topology changes over time. Therefore, it is not accurate to depict the social relationships of people based on a static network. In this paper, we present a survey of this emerging field from a temporal perspective. The state-of-the-art research of MSNs is reviewed with focus on four aspects: social property, time-varying graph, temporal social property, and temporal social properties-based applications. Some important open issues with respect to MSNs are discussed