266 research outputs found

    Culture as the Basis of The Good Entrepreneur

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    Human beings may have conquered markets, introduced technical innovations, built enterprises, and accumulated great wealth, but we may be failing in one of the most important tasks of our culture – the passing on of a moral tradition that builds good character in our children that contributes to the moral and spiritual capital of the country. Entrepreneurs are not only a powerful force in our economy, but also our culture because they create trends, break molds, and cause significant changes within society. Their enormous creativity stems from their skills, experiences, and characteristics – habits if you will – that some people describe as “entrepreneurial virtues.” Christianity and particularly Catholicism, for example, has developed a social tradition that reconnects the entrepreneur’s work to a moral and spiritual vision of the enterprise. When Christian culture is at its best, it generates an economic order that humanizes the entrepreneurial realm in a way that generates faithful companies that contribute to the common good

    Locality-Aware Distribution Schemes

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    One of the bottlenecks in parallel query processing is the cost of shuffling data across nodes in a cluster. Ideally, given a distribution of the data across the nodes and a query, we want to execute the query by performing only local computation and no communication: in this case, the query is called parallel-correct with respect to the data distribution. Previous work studied this problem for Conjunctive Queries in the case where the distribution scheme is oblivious, i.e., the location of each tuple depends only on the tuple and is independent of the instance. In this work, we show that oblivious schemes have a fundamental theoretical limitation, and initiate the formal study of distribution schemes that are locality-aware. In particular, we focus on a class of distribution schemes called co-hash distribution schemes, which are widely used in parallel systems. In co-hash partitioning, some tables are initially hashed, and the remaining tables are co-located so that a join condition is always satisfied. Given a co-hash distribution scheme, we formally study the complexity of deciding various desirable properties, including obliviousness and redundancy. Then, for a given Conjunctive Query and co-hash scheme, we determine the computational complexity of deciding whether the query is parallel-correct. We also explore a stronger notion of correctness, called parallel disjoint correctness, which guarantees that the query result will be disjointly partitioned across nodes, i.e., there is no duplication of results

    Neuroelectronic and Nanophotonic Devices Based on Nanocoaxial Arrays

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    Thesis advisor: Michael J. NaughtonThesis advisor: Michael J. BurnsRecent progress in the study of the brain has been greatly facilitated by the development of new measurement tools capable of minimally-invasive, robust coupling to neuronal assemblies. Two prominent examples are the microelectrode array, which enables electrical signals from large numbers of neurons to be detected and spatiotemporally correlated, and optogenetics, which enables the electrical activity of cells to be controlled with light. In the former case, high spatial density is desirable but, as electrode arrays evolve toward higher density and thus smaller pitch, electrical crosstalk increases. In the latter, finer control over light input is desirable, to enable improved studies of neuroelectronic pathways emanating from specific cell stimulation. Herein, we introduce a coaxial electrode architecture that is uniquely suited to address these issues, as it can simultaneously be utilized as an optical waveguide and a shielded electrode in dense arrays.Thesis (PhD) — Boston College, 2017.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Physics

    m-tables: Representing Missing Data

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    Representation systems have been widely used to capture different forms of incomplete data in various settings. However, existing representation systems are not expressive enough to handle the more complex scenarios of missing data that can occur in practice: these could vary from missing attribute values, missing a known number of tuples, or even missing an unknown number of tuples. In this work, we propose a new representation system called m-tables, that can represent many different types of missing data. We show that m-tables form a closed, complete and strong representation system under both set and bag semantics and are strictly more expressive than conditional tables under both the closed and open world assumptions. We further study the complexity of computing certain and possible answers in m-tables. Finally, we discuss how to "interpret" m-tables through a novel labeling scheme that marks a type of generalized tuples as certain or possible

    On the complexity of privacy-preserving complex event processing

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    Complex Event Processing (CEP) Systems are stream processing systems that monitor incoming event streams in search of user-specified event patterns. While CEP systems have been adopted in a variety of applications, the privacy implications of event pattern reporting mechanisms have yet to be studied — a stark contrast to the significant amount of attention that has been devoted to privacy for relational systems. In this paper we present a privacy problem that arises when the system must support desired patterns (those that should be reported if detected) and private patterns (those that should not be revealed). We formalize this problem, which we term privacy-preserving, utility maximizing CEP (PP-CEP), and analyze its complexity under various assumptions. Our results show that this is a rich problem to study and shed some light on the difficulty of developing algorithms that preserve utility without compromis-ing privacy
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