759 research outputs found

    The impact of banking competition on firm total factor productivity

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    The benefits of financial development to economic growth are conspicuous, but due to the heterogeneity across regions and firms, the effects of financial competition have not been fully proved. There is a puzzling phenomenon in many developing countries, that is, banking monopoly coexists with economic growth. This study uses industrial enterprise data to analyse how banking competition affects firm total factor productivity (T.F.P.) and the influence of firm size and ownership in this process. The results show that the competition in banking promotes firms to improve their T.F.P., which is realised by alleviating financing constraints of firms through increasing banking competition and aligns with the market power hypothesis. Moreover, banking competition enables small firms to improve their T.F.P. in regions with fewer state-owned banks branches and more small banks branches. Intensified competition in banking leads to an increase in the T.F.P. of private firms, but it has no effect on the T.F.P. of state-owned enterprises (S.O.E.s) and foreign firms. The expansion of bank branches and the cross region operation of city commercial banks are helpful to improve firm T.F.P. This study confirms the impact of competition caused by changes in bank branches on firms and the determinants of productivit

    The impact of corruption on firms’ access to bank loans: evidence from China

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    Current theories cannot explain the coexistence of China’s 40 years of rapid economic growth and its imperfect financial system, insufficient investor protection, and government intervention. This study empirically tests hypotheses regarding the effects of corruption on firms’ access to bank loans using econometric models based on survey data of 2,848 enterprises in China collected by the World Bank. The results show an inverted U-shaped relationship between corruption and firms’ access to bank loans: a low level of corruption increases firms’ access to bank loans, whereas a high level of corruption hinders firms from obtaining bank loans. Mild corruption may be a suboptimal choice for firms seeking bank loans, and bank funds allocation based on corruption can achieve Pareto optimality among firms. Moreover, government guarantees are conducive to firms’ access to financing and the link between corruption and firms’ access to bank loans can be explained by the role of government guarantees. The improvement of institutional quality is positively associated with firms’ access to bank loans and weakens the effects of corruption on firms’ external financing. This study thus sheds light on the real effects of corruption and the determinants of firms’ access to bank loans in developing countries

    Photometric Stereo-Based Depth Map Reconstruction for Monocular Capsule Endoscopy

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    The capsule endoscopy robot can only use monocular vision due to the dimensional limit. To improve the depth perception of the monocular capsule endoscopy robot, this paper proposes a photometric stereo-based depth map reconstruction method. First, based on the characteristics of the capsule endoscopy robot system, a photometric stereo framework is established. Then, by combining the specular property and Lambertian property of the object surface, the depth of the specular highlight point is estimated, and the depth map of the whole object surface is reconstructed by a forward upwind scheme. To evaluate the precision of the depth estimation of the specular highlight region and the depth map reconstruction of the object surface, simulations and experiments are implemented with synthetic images and pig colon tissue, respectively. The results of the simulations and experiments show that the proposed method provides good precision for depth map reconstruction in monocular capsule endoscopy

    Endoluminal Motion Recognition of a Magnetically-Guided Capsule Endoscope Based on Capsule-Tissue Interaction Force

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    A magnetically-guided capsule endoscope, embedding flexible force sensors, is designed to measure the capsule-tissue interaction force. The flexible force sensor is composed of eight force-sensitive elements surrounding the internal permanent magnet (IPM). The control of interaction force acting on the intestinal wall can reduce patient's discomfort and maintain the magnetic coupling between the external permanent magnet (EPM) and the IPM during capsule navigation. A flexible force sensor can achieve this control. In particular, by analyzing the signals of the force sensitive elements, we propose a method to recognize the status of the motion of the magnetic capsule, and provide corresponding formulas to evaluate whether the magnetic capsule follows the motion of the external driving magnet. Accuracy of the motion recognition in Ex Vivo tests reached 94% when the EPM was translated along the longitudinal axis. In addition, a method is proposed to realign the EPM and the IPM before the loss of their magnetic coupling. Its translational error, rotational error, and runtime are 7.04 ± 0.71 mm, 3.13 ± 0.47∘, and 11.4 ± 0.39 s, respectively. Finally, a control strategy is proposed to prevent the magnetic capsule endoscope from losing control during the magnetically-guided capsule colonoscopy

    Effect of post-peak cyclic load on mechanics and seepage characteristics of sandstone under different confining pressures

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    The mining disturbance causes the rock mass in a certain range of the coal seam floor to be in a post-peak state. Due to the excavation of adjacent roadways and the mining of coal seams, the post-peak rock mass undergoes a cyclic loading-unloading process. In order to explore the influence of post-peak cyclic loading on rock mass structure under different in-situ stress environments and clarify the gestation process of disasters such as water inrush from coal seam floor, post-peak cyclic loading tests of sandstone under 5,10,15,20,25 MPa confining pressure were carried out based on Rock Top multi-field coupling tester. The results show that: ① Before the post-peak cyclic loading, the unit permeability of rock shows a rapid decline-tend to be stable-sudden rise-sudden decline-tend to be stable. In the post-peak cycle stage, the unit permeability of rock is almost inverted with the axial load. ② Rock elastic modulus, crack closure stress, crack initiation stress, damage stress, peak stress and residual stress are positively correlated with confining pressure, while Poisson 's ratio increases first and then decreases with the increase of confining pressure. ③ Under the confining pressure of 5 and 10 MPa, the intermittent failure of rock occurs, and the brittle failure characteristics are weakened. Under the confining pressure of 15, 20 and 25 MPa, the brittle failure characteristics of rock are obvious, and the failure characteristics of rock are determined by the properties of rock itself. ④ The post-peak axial load mainly promotes the increase of rock permeability, but the promotion effect is weaker than that of confining pressure on rock permeability, and confining pressure is the dominant factor affecting the post-peak permeability change of rock. ⑤ Under different confining pressures, a through-shear crack occurs in all rocks, but with the increase of confining pressure, the degree of rock failure gradually weakens and the failure mode tends to be simple

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

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    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Azimuthal separation in nearly back-to-back jet topologies in inclusive 2-and 3-jet events in pp collisions at root s=13TeV

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    A measurement for inclusive 2- and 3-jet events of the azimuthal correlation between the two jets with the largest transverse momenta, Delta phi(12), is presented. The measurement considers events where the two leading jets are nearly collinear ("back-to-back") in the transverse plane and is performed for several ranges of the leading jet transverse momentum. Proton-proton collision data collected with the CMS experiment at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 35.9 fb(-1) are used. Predictions based on calculations using matrix elements at leading-order and next-to-leading-order accuracy in perturbative quantum chromodynamics supplemented with leading-log parton showers and hadronization are generally in agreement with themeasurements. Discrepancies between the measurement and theoretical predictions are as large as 15%, mainly in the region 177 degrees <Delta phi(12) <180 degrees. The 2- and 3-jet measurements are not simultaneously described by any of models.Peer reviewe
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