Non-Cooperative Rational Interactive Proofs

Interactive-proof games model the scenario where an honest party interacts with powerful but strategic provers, to elicit from them the correct answer to a computational question. Interactive proofs are increasingly used as a framework to design protocols for computation outsourcing. Existing interactive-proof games largely fall into two categories: either as games of cooperation such as multi-prover interactive proofs and cooperative rational proofs, where the provers work together as a team; or as games of conflict such as refereed games, where the provers directly compete with each other in a zero-sum game. Neither of these extremes truly capture the strategic nature of service providers in outsourcing applications. How to design and analyze non-cooperative interactive proofs is an important open problem. In this paper, we introduce a mechanism-design approach to define a multi-prover interactive-proof model in which the provers are rational and non-cooperative - they act to maximize their expected utility given others\u27 strategies. We define a strong notion of backwards induction as our solution concept to analyze the resulting extensive-form game with imperfect information. We fully characterize the complexity of our proof system under different utility gap guarantees. (At a high level, a utility gap of u means that the protocol is robust against provers that may not care about a utility loss of 1/u.) We show, for example, that the power of non-cooperative rational interactive proofs with a polynomial utility gap is exactly equal to the complexity class P^{NEXP}

Gunrock: GPU Graph Analytics

For large-scale graph analytics on the GPU, the irregularity of data access and control flow, and the complexity of programming GPUs, have presented two significant challenges to developing a programmable high-performance graph library. "Gunrock", our graph-processing system designed specifically for the GPU, uses a high-level, bulk-synchronous, data-centric abstraction focused on operations on a vertex or edge frontier. Gunrock achieves a balance between performance and expressiveness by coupling high performance GPU computing primitives and optimization strategies with a high-level programming model that allows programmers to quickly develop new graph primitives with small code size and minimal GPU programming knowledge. We characterize the performance of various optimization strategies and evaluate Gunrock's overall performance on different GPU architectures on a wide range of graph primitives that span from traversal-based algorithms and ranking algorithms, to triangle counting and bipartite-graph-based algorithms. The results show that on a single GPU, Gunrock has on average at least an order of magnitude speedup over Boost and PowerGraph, comparable performance to the fastest GPU hardwired primitives and CPU shared-memory graph libraries such as Ligra and Galois, and better performance than any other GPU high-level graph library.Comment: 52 pages, invited paper to ACM Transactions on Parallel Computing (TOPC), an extended version of PPoPP'16 paper "Gunrock: A High-Performance Graph Processing Library on the GPU

Exploratory study to explore the role of ICT in the process of knowledge management in an Indian business environment

In the 21st century and the emergence of a digital economy, knowledge and the knowledge base economy are rapidly growing. To effectively be able to understand the processes involved in the creating, managing and sharing of knowledge management in the business environment is critical to the success of an organization. This study builds on the previous research of the authors on the enablers of knowledge management by identifying the relationship between the enablers of knowledge management and the role played by information communication technologies (ICT) and ICT infrastructure in a business setting. This paper provides the findings of a survey collected from the four major Indian cities (Chennai, Coimbatore, Madurai and Villupuram) regarding their views and opinions about the enablers of knowledge management in business setting. A total of 80 organizations participated in the study with 100 participants in each city. The results show that ICT and ICT infrastructure can play a critical role in the creating, managing and sharing of knowledge in an Indian business environment

The Mobile Phone as a Globalising Artefact

This paper presents the findings from a qualitative study of mobile phones and youth culture in Melbourne, Australia. The focus is on how the social dynamic resulting from the use of such communications tools has created a paradigm shift that has changed the nature of inter-human relations. Mobile facilitated interaction is driving a fundamental change in social mores with respect to engagement and commitment, to notions of fluid time versus fixed time and ultimately to urban mobility. Connectivity is becoming central to what it means to have a social identity and users are responding to this by merging bits of data to create their ‘ideal digital self’ through which they communicate socially. This calls into question the nature of ‘digital identity’, indicating it is not only about how much information can be restricted, but rather, what is revealed. While the results are based on a localized study, it is proposed that this phenomenon is happening across societies and that mobile phones themselves are becoming the globalizing icon of youth culture in the early 21st Century

Factors influencing the success of computer mediated communication (CMC) environments in university teaching: a review and case study

Despite its potential benefits, the effectiveness of CMC when used to support learning in higher education is very variable, making it important to identify those factors which best predict successful implementations. A review of the literature from the past few years, presented in the first half of this paper, suggests that, consistent with Activity Theory (Leont'ev, 1978), the critical factors are those which provide a context and rationale for online communication by helping users to establish a shared purpose. However, generating empirical support for this hypothesis presents two kinds of methodological problem: specifying the methods and measures necessary to discern the existence and impact of shared purpose; and dealing with the difficulties of making controlled comparisons in this area. The second half of the paper illustrates, via an implementation case study, something of how these methodological problems might be resolved, and presents evidence in favour of the central importance of shared purpose