6,776 research outputs found

    Accessing Textual Information Embedded in Internet Images

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    Indexing and searching for WWW pages is relying on analysing text. Current technology cannot process the text embedded in images on WWW pages. This paper argues that this is a significant problem as text in image form is usually semantically important (e.g. headers, titles). The results of a recent study are presented to show that the majority (76%) of words embedded in images do not appear elsewhere in the main text and that the majority (56%) of ALT tag descriptions of images are incorrect or do not exist at all. Research under way to devise tools to extract text from images based on the way humans perceive colour differences is outlined and results are presented

    A Model to Describe Transport Properties in Bi2Sr2(CazPr1−z)Cu2O8+yBi_2Sr_2(Ca_zPr_{1-z})Cu_2O_{8+y}

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    A pseudo-spin model is proposed, as a means to describe some transport properties (resistivity and Hall mobility) in Bi2Sr2(CazPr1−z)Cu2O8+yBi_2Sr_2(Ca_zPr_{1-z})Cu_2O_{8+y}. Our model is based in a double-well potential where tunneling in a given site and interaction between different lattice sites are allowed only through the excited states. Doping of the pure system by the addition of PrPr increases the ratio between the activation energy and the tunneling constant. The model Hamiltonian displays some features which are present in the hydrogen-bonded ferroelectrics. Its dynamics is treated in the random phase approximation and the characteristic frequency (time) is used in a Drude formula in order to obtain some transport properties of the system, namely the electric resistivity and the Hall mobility. The quantities calculated in this work are compared with the experimental data of B. Beschoten, S. Sadewasser, G. G\"{u}ntherodt and C. Quitmann [Phys. Rev. Lett.77, 1837(1996)].Comment: 14 pages, 4 figure

    "Effective Demand in the Recent Evolution of the US Economy"

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    We present strong empirical evidence favoring the role of effective demand in the US economy, in the spirit of Keynes and Kalecki. Our inference comes from a statistically well-specified VAR model constructed on a quarterly basis from 1980 to 2008. US output is our variable of interest, and it depends (in our specification) on (1) the wage share, (2) OECD GDP, (3) taxes on corporate income, (4) other budget revenues, (5) credit, and the (6) interest rate. The first variable was included in order to know whether the economy under study is wage led or profit led. The second represents demand from abroad. The third and fourth make up total government expenditure and our arguments regarding these are based on Kalecki's analysis of fiscal policy. The last two variables are analyzed in the context of Keynes's monetary economics. Our results indicate that expansionary monetary, fiscal, and income policies favor higher aggregate demand in the United States.Effective Demand; Wage Shares; Monetary Policy; Fiscal Policy; Model Evaluation

    A vulnerability approach to the definition of the middle class

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    Measurement of the middle class has recently come to the center of policy debate in middle-income countries as they search for the potential engines of growth and good governance. This debate assumes, first, that there is a meaningful definition of class, and second, that thresholds that define relatively homogeneous groups in terms of pre-determined sociological characteristics can be found empirically. This paper aims at proposing a view of the middle class based on vulnerability to poverty. Following this approach the paper exploits panel data to determine the amount of comparable income -- associated with a low probability of falling into poverty -- which could define the lower bound of the middle class. The paper looks at absolute thresholds, challenging the view that people above the poverty line are actually part of the middle class. The estimated lower threshold is used in cross-section surveys to quantify the size and the evolution of middle classes in Chile, Mexico, and Peru over the past two decades. The first relevant feature relates to the fact that the proposed thresholds lie around the 60th percentile of the distribution. The evidence also shows that the middle class has increased significantly in all three countries, suggesting that a higher number of households face lower probabilities of falling into poverty than they did in the 1990s. There is an important group of people, however, which cannot be defined as middle class from this perspective, but are not eligible for poverty programs according to traditional definitions of poverty.Rural Poverty Reduction,Inequality,Regional Economic Development,Urban Partnerships&Poverty,Services&Transfers to Poor

    Enhanced Sorption Process for the Production of Hydrogen.

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    Addition of an inexpensive calcium-based CO2 acceptor (dolomite) to a commercial reforming catalyst resulted in the production of 95+% H 2 from CH4 using sorption-enhanced reaction (SER). The combined reforming, shift, and CO2 separation reactions were sufficiently fast that combined reaction equilibrium was closely approached at 15 atm and 650°C. Process simulations showed that in addition to requiring fewer processing steps, SER permits lower reformer temperature, eliminates the need for shift catalysts, and provides a potential energy savings of 20--25% compared to conventional steam-methane reforming (SMR). An off-gas of pure, sequestration-ready CO2 for greenhouse gas emission control is possible using SER. In a commercial process the acceptor must retain activity through many reaction-regeneration cycles. Multicycle durability tests of the CO2 acceptor and reforming catalyst consisting of as many as twenty-five cycles in a fixed-bed reactor and 150 cycles in an electrobalance reactor were performed. These tests examined the effects of sorbent regeneration temperature and gas composition with the sorbent both mixed with and separated from the reforming catalyst prior to regeneration. In a typical twenty-five-cycle test, there was no decrease in maximum H2 concentration, but a gradual decrease in global reaction rate and fractional carbonation of the sorbent were observed. This gradual decrease in performance is explained on the basis of changes in structural properties of the catalyst and acceptor

    Video Tester -- A multiple-metric framework for video quality assessment over IP networks

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    This paper presents an extensible and reusable framework which addresses the problem of video quality assessment over IP networks. The proposed tool (referred to as Video-Tester) supports raw uncompressed video encoding and decoding. It also includes different video over IP transmission methods (i.e.: RTP over UDP unicast and multicast, as well as RTP over TCP). In addition, it is furnished with a rich set of offline analysis capabilities. Video-Tester analysis includes QoS and bitstream parameters estimation (i.e.: bandwidth, packet inter-arrival time, jitter and loss rate, as well as GOP size and I-frame loss rate). Our design facilitates the integration of virtually any existing video quality metric thanks to the adopted Python-based modular approach. Video-Tester currently provides PSNR, SSIM, ITU-T G.1070 video quality metric, DIV and PSNR-based MOS estimations. In order to promote its use and extension, Video-Tester is open and publicly available.Comment: 5 pages, 5 figures. For the Google Code project, see http://video-tester.googlecode.com

    The Decline in Inequality in Latin America: How Much, Since When and Why

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    Between 2000 and 2009, the Gini coefficient declined in 13 of 17 Latin American countries for which comparable data exist. The decline was statistically significant and robust to changes in the time interval, inequality measures and data sources. In depth country studies for Argentina, Brazil, Mexico and Peru suggest that there are two phenomena which underlie this trend: (i) a fall in the premium to skilled labor (as measured by returns to education); and (ii) higher and more progressive government transfers. The fall in the premium to skills results from a combination of supply and demand factors and, in Argentina and, to a lesser extent, in Brazil, from more active labor market policies as well.Income inequality, wage gap, government transfers, Latin America

    The decline in inequality in Latin America: How much, since when and why

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    Between 2000 and 2009, the Gini coefficient declined in 13 of 17 Latin American countries for which comparable data exist. The decline was statistically significant and robust to changes in the time interval, inequality measures and data sources. In depth country studies for Argentina, Brazil, Mexico and Peru suggest that there are two phenomena which underlie this trend: (i) a fall in the premium to skilled labor (as measured by returns to education); and (ii) higher and more progressive government transfers. The fall in the premium to skills results from a combination of supply and demand factors and, in Argentina—and to a lesser extent in Brazil--, from more active labor market policies as well.Income inequality, wage gap, government transfers, Latin America.

    Bounded Protocols for Efficient Reliable Message Transmission

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    In the reliable message transmission problem (RMTP) processors communicate by exchanging messages, but the channel that connects two processors is subject to message loss, duplication, and reordering. Previous work focused on proposing protocols in asynchronous systems, where message size is finite and sequence numbers are bounded. However, if the channel can duplicate messages, lose messages, and arbitrarily reorder the messages, the problem is unsolvable. In this thesis, we consider a strengthening of the asynchronous model in which reordering of messages is bounded. In this model, we develop two efficient protocols to solve the RMTP: (1) when messages may be duplicated but not lost and (2) when messages may be duplicated and lost. This result is in contrast to the impossibility of such an algorithm when reordering is unbounded. Our protocols have the pleasing property that no messages need to be sent from the receiver to the sender
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