1,422 research outputs found

    Data Structure for a Time-Based Bandwidth Reservations Problem

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    We discuss a problem of handling resource reservations. The resource can be reserved for some time, it can be freed or it can be queried what is the largest amount of reserved resource during a time interval. We show that the problem has a lower bound of Ω(log⁥n)\Omega(\log n) per operation on average and we give a matching upper bound algorithm. Our solution also solves a dynamic version of the related problems of a prefix sum and a partial sum

    Static Data Structure for Discrete Advance Bandwidth Reservations on the Internet

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    In this paper we present a discrete data structure for reservations of limited resources. A reservation is defined as a tuple consisting of the time interval of when the resource should be reserved, IRI_R, and the amount of the resource that is reserved, BRB_R, formally R={IR,BR}R=\{I_R,B_R\}. The data structure is similar to a segment tree. The maximum spanning interval of the data structure is fixed and defined in advance. The granularity and thereby the size of the intervals of the leaves is also defined in advance. The data structure is built only once. Neither nodes nor leaves are ever inserted, deleted or moved. Hence, the running time of the operations does not depend on the number of reservations previously made. The running time does not depend on the size of the interval of the reservation either. Let nn be the number of leaves in the data structure. In the worst case, the number of touched (i.e. traversed) nodes is in any operation O(log⁥n)O(\log n), hence the running time of any operation is also O(log⁥n)O(\log n)

    Good for Living? On the Relation between Globalization and Life Expectancy

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    This paper analyzes the relation between three dimensions of globalization (economic, social and political) and life expectancy using a panel of 92 countries over the period 1970-2005. Using different estimation techniques and sample groupings we find a very robust positive effect from economic globalization on life expectancy, even when controlling for income, nutritional intake, literacy, number of physicians and several other factors. The result also holds when the sample is restricted to low income countries only. For political and social globalization we find no robust effects.Globalization; health; life expectancy; development

    Globalization and Absolute Poverty – A Panel Data Study

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    Using panel data from more than 100 countries around the world from 1988 through 2007, this paper examines the relationship between economic and social globalization and absolute income poverty ex post. We use the globalization index developed by Dreher (2006) and the World Bank poverty estimates. Using a fixed-effect panel based on five-year averages and using a “long run” first difference regression, we find a robust negative correlation between globalization and poverty. We further examine mechanisms and robustness by separately analyzing the effects of components of economic (trade flows and trade policies) and social globalization (information flows, personal contact and cultural proximity) respectively, controlling for growth, education, inflation, urbanization, and government consumption. Results suggest that information flows and more liberal trade restrictions are robustly negatively correlated with absolute poverty. While growth decreases poverty in the long run, only a small part of the poverty-reducing effect of globalization is mediated via growth.Globalization; Poverty; Panel Data

    An O(1) Solution to the Prefix Sum Problem on a Specialized Memory Architecture

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    In this paper we study the Prefix Sum problem introduced by Fredman. We show that it is possible to perform both update and retrieval in O(1) time simultaneously under a memory model in which individual bits may be shared by several words. We also show that two variants (generalizations) of the problem can be solved optimally in Θ(lg⁥N)\Theta(\lg N) time under the comparison based model of computation.Comment: 12 page

    Fast all-optical nuclear spin echo technique based on EIT

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    We demonstrate an all-optical Raman spin echo technique, using Electromagnetically Induced Transparency (EIT) to create the different pulses of the spin echo sequence: initialization, pi-rotation, and readout. The first pulse of the sequence induces coherence directly from a mixed state, and the technique is used to measure the nuclear spin coherence of an inhomogeneously broadened ensemble of rare-earth ions (Pr3+^{3+}). In contrast to previous experiments it does not require any preparatory hole burning pulse sequences, which greatly shortens the total duration of the sequence. The effect of the different pulses is characterized by quantum state tomography and is compared with simulations. We demonstrate two applications of the technique by using the spin echo sequence to accurately compensate a magnetic field across our sample, and to measure the coherence time at high temperatures up to 11 K, where standard preparation techniques are difficult to implement. We explore the potential of the technique and possible applications.Comment: 8 pages, 6 figure

    Navigation Devices for Mobile Phones

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    A mobile phone has several buttons/keys e.g. numerical keys, side keys, camera buttons and navigation keys. SEMC, Sony Ericsson Mobile Communications AB, has mainly used the joystick and the rocker key as their navigation devices since they released their first phone in 2002. These technologies are used in all their phones except smart phones, e.g. W950 and P990. During the years SEMC has experienced some quality problems with their navigation devices, mainly with the joystick, because of the lack of ability to keep dust out. As the development of mobile phones progress, with more functions and larger quantity of data to go through, the need of a navigation device with more possibilities arise. The purpose of this master thesis was to perform a pre-study on the next generation navigation devices for mobile phones and based on that give recommendations to SEMC of which navigation devices suitable to be used in the future

    Invariant multipliers and O(p, q)-action

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    In this paper we consider multipliers satisfying some invariance conditions coming from O(p, q). We will also investigate LpL_p-boundedness for some of the operators
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