65 research outputs found

    Does the Solow Residual for Korea Reflect Pure Technology Shocks?

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    This study investigates the relationship between the measured Solow residual and demand side variables for the Korean economy. The measured Solow residuals are shown to be Granger-caused by some demand side variables such as exports, M1, and government expenditure. A vector error correction model is constructed to investigate dynamic relation between these demand side variables and the Solow residual. Impulse response functions shows that the measured Solow residual moves pro-cyclically with the demand shocks, and that the forecast error variance of the measured Solow residual is mostly explained by past innovations of these demand side variablesSolow residual, Productivity shock, Vector error correction model

    Imports, exports, and total factor productivity in Korea

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    Learning Symmetric Rules with SATNet

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    SATNet is a differentiable constraint solver with a custom backpropagation algorithm, which can be used as a layer in a deep-learning system. It is a promising proposal for bridging deep learning and logical reasoning. In fact, SATNet has been successfully applied to learn, among others, the rules of a complex logical puzzle, such as Sudoku, just from input and output pairs where inputs are given as images. In this paper, we show how to improve the learning of SATNet by exploiting symmetries in the target rules of a given but unknown logical puzzle or more generally a logical formula. We present SymSATNet, a variant of SATNet that translates the given symmetries of the target rules to a condition on the parameters of SATNet and requires that the parameters should have a particular parametric form that guarantees the condition. The requirement dramatically reduces the number of parameters to learn for the rules with enough symmetries, and makes the parameter learning of SymSATNet much easier than that of SATNet. We also describe a technique for automatically discovering symmetries of the target rules from examples. Our experiments with Sudoku and Rubik's cube show the substantial improvement of SymSATNet over the baseline SATNet.Comment: 27 pages, 10 figures, the first two authors contributed equally to this work, accepted at NeurIPS'2

    The Effect of Imports and Exports on Total Factor Productivity in Korea

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    We investigate the effect of imports and exports on total factor productivity in Korea during 1980-2003. We find Granger causality from imports to total factor productivity (TFP) growth, but no causality from exports to TFP growth. We then investigate the impact of trade and other variables on TFP growth. According to our results, imports have a significant positive effect on TFP growth but exports do not. In addition, our results indicate that the positive impact of imports arises not only from the competitive pressures associated with the imports of consumer goods but also from technological transfers embodied in imports of capital goods from developed countries.

    Analysis Method for Determining Optimal Synthetic Aperture Time Using Estimated Range and Doppler Cone Angle at the Center of Synthetic Aperture Length

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    Synthetic aperture time (SAT) is a crucial component for acquiring high-quality synthetic aperture radar images with an excellent target cross-range resolution. SAT is analyzed using the range and Doppler cone angle at the center of the synthetic aperture length (SAL). However, in a real flight mission setting, only the range and Doppler cone angle at the SAL’s starting point are determined. Therefore, we present a method for estimating the range and Doppler cone angle at the center of the SAL to calculate an accurate SAT that is suitable for the spatial resolution of the assigned mission. We performed an iterative analysis of SAT at the range and Doppler cone angle at the starting point of the SAL (original SAT) and at the center of the SAL (proposed SAT). Consequently, the proposed SAT decreased by 0.69%–16.14% compared to the original SAT at a resolution of 0.1–3.0 m

    A Case of a Pulmonary Arteriovenous Malformation With Ebstein's Anomaly

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    A pulmonary arteriovenous malformation (PAVM) is a rare pulmonary vascular anomaly presenting as dyspnea or recurrent epistaxis. Ebstein's anomaly (EA), a congenital cardiac malformation, is also a rare condition. There have been no reports concerning the co-existence of PAVM with hereditary hemorrhagic telangiectasia (HHT) and EA. A 40-year-old woman was admitted with a 2-month history of increasing dyspnea and several years of recurrent epistaxis. On transthoracic echocardiography, she was diagnosed with EA and agreed to undergo surgical treatment. A chest CT angiography showed a 12-mm serpiginous vascular structure suspicious for a PAVM and a liver CT suggested HTT. Although it is unclear whether or not a concurrent PAVM and EA have an embryologic or genetic relationship, we report a case of a PAVM with EA. Further genetic and embryonic studies are needed to identify a possible relationship of the two medical conditions

    Roles of Inflammatory Biomarkers in Exhaled Breath Condensates in Respiratory Clinical Fields

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    Background Exhaled condensates contain inflammatory biomarkers; however, their roles in the clinical field have been under-investigated. Methods We prospectively enrolled subjects admitted to pulmonology clinics. We collected exhaled breath condensates (EBC) and analysed the levels of six and 12 biomarkers using conventional and multiplex enzyme-linked immunosorbent assay, respectively. Results Among the 123 subjects, healthy controls constituted the largest group (81 participants; 65.9%), followed by the preserved ratio impaired spirometry group (21 patients; 17.1%) and the chronic obstructive pulmonary disease (COPD) group (21 patients; 17.1%). In COPD patients, platelet derived growth factor-AA exhibited strong positive correlations with COPD assessment test (ρ=0.5926, p=0.0423) and COPD-specific version of St. George’s Respiratory Questionnaire (SGRQ-C) score (total, ρ=0.6725, p=0.0166; activity, ρ=0.7176, p=0.0086; and impacts, ρ=0.6151, p=0.0333). Granzyme B showed strong positive correlations with SGRQ-C score (symptoms, ρ=0.6078, p=0.0360; and impacts, ρ=0.6007, p=0.0389). Interleukin 6 exhibited a strong positive correlation with SGRQ-C score (activity, ρ=0.4671, p=0.0378). The absolute serum eosinophil and basophil counts showed positive correlations with pro-collagen I alpha 1 (ρ=0.6735, p=0.0164 and ρ=0.6295, p=0.0283, respectively). In healthy subjects, forced expiratory volume in 1 second (FEV1)/forced vital capacity demonstrated significant correlation with CC chemokine ligand 3 (CCL3)/macrophage inflammatory protein 1 alpha (ρ=0.3897 and p=0.0068). FEV1 exhibited significant correlation with CCL11/eotaxin (ρ=0.4445 and p=0.0017). Conclusion Inflammatory biomarkers in EBC might be useful to predict quality of life concerning respiratory symptoms and serologic markers. Further studies are needed

    A Geometric Mean of Parameterized Arithmetic and Harmonic Means of Convex Functions

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    The notion of the geometric mean of two positive reals is extended by Ando (1978) to the case of positive semidefinite matrices A and B. Moreover, an interesting generalization of the geometric mean A # B of A and B to convex functions was introduced by Atteia and Raïssouli (2001) with a different viewpoint of convex analysis. The present work aims at providing a further development of the geometric mean of convex functions due to Atteia and Raïssouli (2001). A new algorithmic self-dual operator for convex functions named “the geometric mean of parameterized arithmetic and harmonic means of convex functions” is proposed, and its essential properties are investigated

    Penalized complementarity functions on symmetric cones

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    Complementarity problem, Complementarity functions, Merit functions, Symmetric cones, Primary: 90C33,
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