4,423 research outputs found

    The equilibrium approach to exchange rates: theory and tests.

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    We characterize the equilibrium exchange rate in a general equilibrium economy without imposing strong restrictions on the output processes, preferences, or commodity market imperfections. The nomial exchange rate is determined by differences in initial wealths - the currencies of richer countries tend to be overvalued, by PPP standards - and by differences of marginal indirect utilities of total nominal spending. Changes in the exchange rate mirror differences in growth rates of real spending weighted by relative risk-aversion (which can be time-varying and can differ across countries), and, in the case of non-homothetic utility functions, differences in inflation rates computed from marginal spending weights. Thus, standard regression or cointegration tests of PPP suffer from missing-variables biases and ignore variations in risk aversions across countries and over time. We also present cointegration test of the homothecy/ CRRA version of the model. When nominal spending is given an independent role (next to prices) in the short-term dynamics, both PPP and the CRRA model become acceptable.Equilibrium; Theory; Trade;

    The exchange rate and purchasing power parity: extending the theory and tests.

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    This paper analyzes the exchange rate in a ``no-arbitrage' or ``real business cycle' equilibrium model and provides empirical evidence for this model vis-a-vis PPP. Our contribution is to show, based on a generalization of the equilibrium model of exchange rates, that (i) the test equation linking the exchange rate to fundamentals should allow for international heterogeneity in time preferences or risk attitudes, as well as noise---that is, the model should not be tested as an exact relation; (ii) empirical work should use levels of variables rather than first differences; (iii) tests on the existence of long-run relations should be complemented by tests on the signs of the coefficients; (iv) the specification of the regression should offer demonstrated advantages over alternatives, and the significance tests should not rely on asymptotic distributions; and (v) the tests should steer clear of countries that have imposed, for most of the period, capital restrictions or exchange controls, thus violating the integrated-markets assumption of the model. Our empirical work shows that, as a long-run relation, the generalized model outperforms PPP.Purchasing; Purchasing power; Theory; Equilibrium; Model; International; Risk; Variables; Advantages; Distribution;

    Jabba: hybrid error correction for long sequencing reads using maximal exact matches

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    Third generation sequencing platforms produce longer reads with higher error rates than second generation sequencing technologies. While the improved read length can provide useful information for downstream analysis, underlying algorithms are challenged by the high error rate. Error correction methods in which accurate short reads are used to correct noisy long reads appear to be attractive to generate high-quality long reads. Methods that align short reads to long reads do not optimally use the information contained in the second generation data, and suffer from large runtimes. Recently, a new hybrid error correcting method has been proposed, where the second generation data is first assembled into a de Bruijn graph, on which the long reads are then aligned. In this context we present Jabba, a hybrid method to correct long third generation reads by mapping them on a corrected de Bruijn graph that was constructed from second generation data. Unique to our method is that this mapping is constructed with a seed and extend methodology, using maximal exact matches as seeds. In addition to benchmark results, certain theoretical results concerning the possibilities and limitations of the use of maximal exact matches in the context of third generation reads are presented

    Tahun 2007-2009 Analisis Struktur, Konsentrasi dan Efisiensi Pasar Industri Otomotif dan Produk Otomotif di Indonesia Tahun 2007-2009

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    The purpose of this study is to analyze market structure and efficiency of Automotive Industry in Indonesia periode 2007-2009 market structure is measured by using concentration Ratio and efficiency of the Industry is measured by using Data Enrespment Analysis. The result of this study show that market several of Automotive Industry in Indonesia oligopoly the competition level of Automotive Industry is concentrated and foor automotive company with biggest to me asset here 100% efficiency level for there years. The companies are PT. Astra International, PT. United Tractors, PT. Indomobil Sukses Internasional and PT. Astra Otoparts. While one company that did not had 100% efficiency level from 2007 untuil 2009 is Pt. Gajah Tunggal in addition, can be know that dominanct factor causing the efficiency of PT. Gajah Tunggal is input of capital

    Noiseless manipulation of helical edge state transport by a quantum magnet

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    The current through a helical edge state of a quantum spin Hall insulator may be fully transmitted through a magnetically gapped region due to a combination of spin-transfer torque and spin pumping [Meng et al., Phys. Rev. B 90, 205403 (2014)]. Using a scattering approach, we here argue that in such a system the current is effectively carried by electrons with energies below the magnet- induced gap and well below the Fermi energy. This has striking consequences, such as the absence of shot noise, an exponential suppression of thermal noise, and an obstruction of thermal transport. For two helical edges covered by the same quantum magnet, the device can act as a robust noiseless current splitter

    Polynomial Optimization Methods

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    This thesis is an exposition of ideas and methods that help un- derstanding the problem of minimizing a polynomial over a basic closed semi-algebraic set. After the introduction of some the- ory on mathematical tools such as sums of squares, nonnegative polynomials and moment matrices, several Positivstellensa ̈tze are considered. Positivstellens ̈atze provide sums of squares represen- tations of polynomials, positive on basic closed semi-algebraic sets. Subsequently, semi-definite programming methods, in par- ticular based on Putinar’s Postivstellensatz, are considered. In order to use semi-definite programming, certain degree bounds are set. These bounds give rise to a hierarchy of approximations of the minimum of a polynomial, which will also be discussed. Finally, some new results are given that are obtained by looking at sums of squares representations of a positive polynomial when minimizing over the unit hypercube

    Valuing flexibility in the migration to flexible-grid networks

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    Increasing network demand is expected to put pressure on the available capacity in core networks. Flexible optical networking can now be installed to increase network capacity in light of future traffic demands. However, this technology is still in its infancy and might lack the full functionality that may appear within a few years. When replacing core network equipment, it is therefore important to make the right investment decision between upgrading toward flexible-grid or fixed-grid equipment. This paper researches various installation options using a techno-economic analysis, extended with real option insights, showing the impact of uncertainty and flexibility on the investment decision. By valuing the different options, a correct investment decision can be made
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