5,136 research outputs found

    Rotary One-To-Many (OTM) Novel Actuator

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    The Rotary One-to-Many Project is aimed at designing and realizing an innovative novel actuator capable of emulating human muscle dexterity. This technology utilizes the “One-to-Many” (OTM) concept, which allows a single artificial actuator to store energy in the form of elastic potential energy and drive multiple independently actuated and controlled degrees of freedom (DoF). This technology may prove critical for systems with many DoF like soft-robotics Exomusculature as well as many others. The feasibility of the concept was initially proven using the Linear OTM system, after which, the Rotary OTM system was designed, prototyped, and successfully tested

    Dimension Extractors and Optimal Decompression

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    A *dimension extractor* is an algorithm designed to increase the effective dimension -- i.e., the amount of computational randomness -- of an infinite binary sequence, in order to turn a "partially random" sequence into a "more random" sequence. Extractors are exhibited for various effective dimensions, including constructive, computable, space-bounded, time-bounded, and finite-state dimension. Using similar techniques, the Kucera-Gacs theorem is examined from the perspective of decompression, by showing that every infinite sequence S is Turing reducible to a Martin-Loef random sequence R such that the asymptotic number of bits of R needed to compute n bits of S, divided by n, is precisely the constructive dimension of S, which is shown to be the optimal ratio of query bits to computed bits achievable with Turing reductions. The extractors and decompressors that are developed lead directly to new characterizations of some effective dimensions in terms of optimal decompression by Turing reductions.Comment: This report was combined with a different conference paper "Every Sequence is Decompressible from a Random One" (cs.IT/0511074, at http://dx.doi.org/10.1007/11780342_17), and both titles were changed, with the conference paper incorporated as section 5 of this new combined paper. The combined paper was accepted to the journal Theory of Computing Systems, as part of a special issue of invited papers from the second conference on Computability in Europe, 200

    Towards a Church-Turing-Thesis for Infinitary Computations

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    We consider the question whether there is an infinitary analogue of the Church-Turing-thesis. To this end, we argue that there is an intuitive notion of transfinite computability and build a canonical model, called Idealized Agent Machines (IAMIAMs) of this which will turn out to be equivalent in strength to the Ordinal Turing Machines defined by P. Koepke

    More is Less: Perfectly Secure Oblivious Algorithms in the Multi-Server Setting

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    The problem of Oblivious RAM (ORAM) has traditionally been studied in a single-server setting, but more recently the multi-server setting has also been considered. Yet it is still unclear whether the multi-server setting has any inherent advantages, e.g., whether the multi-server setting can be used to achieve stronger security goals or provably better efficiency than is possible in the single-server case. In this work, we construct a perfectly secure 3-server ORAM scheme that outperforms the best known single-server scheme by a logarithmic factor. In the process, we also show, for the first time, that there exist specific algorithms for which multiple servers can overcome known lower bounds in the single-server setting.Comment: 36 pages, Accepted in Asiacrypt 201

    TWO-STAGE UTILITY MAXIMIZATION AND IMPORT DEMAND SYSTEMS REVISITED: LIMITATIONS AND AN ALTERNATIVE

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    Two-stage utility maximization theory has been widely used in the literature to estimate import demand for agricultural commodities that are often inputs. This article examines the overlooked conceptual and empirical limitations of applying two-stage utility maximization theory to model the demand for imported commodities that are inputs. A discussion is presented about how the underutilized theory of two-stage profit maximization overcomes these limitations. Also discussed are the conditions under which errors illustration of the two-stage profit maximization procedure is provided.Demand and Price Analysis, International Relations/Trade,
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