114,406 research outputs found
Data-Driven Approach to Simulating Realistic Human Joint Constraints
Modeling realistic human joint limits is important for applications involving
physical human-robot interaction. However, setting appropriate human joint
limits is challenging because it is pose-dependent: the range of joint motion
varies depending on the positions of other bones. The paper introduces a new
technique to accurately simulate human joint limits in physics simulation. We
propose to learn an implicit equation to represent the boundary of valid human
joint configurations from real human data. The function in the implicit
equation is represented by a fully connected neural network whose gradients can
be efficiently computed via back-propagation. Using gradients, we can
efficiently enforce realistic human joint limits through constraint forces in a
physics engine or as constraints in an optimization problem.Comment: To appear at ICRA 2018; 6 pages, 9 figures; for associated video, see
https://youtu.be/wzkoE7wCbu
Analysis of bank efficiency of Chinese commercial banks and the effects of institutional changes on bank efficiency.
This study contributes to the well-established efficiency literature with respect to transition economies and developing counties. Although bank efficiency has been a
popular research area in both developed countries and less developed nations, it has been scarce in China mainly due to the lack of data. This study is considered as the first study that comprehensively investigates bank performance using multiple methodologies of financial ratio analysis and stochastic frontier analysis for the period of 1995-2005. The effects of a variety of governance changes have also been differentiated in order to providing policy recommendations for the on-going banking reform. Meanwhile, this study has addressed a number of methodological issues and has developed a more comprehensive stochastic distance function model by combining advantages of existing models, approaches, methods and procedures.
Having experienced fundamental banking reforms for more than a quarter of century, the Chinese banking System has stridden towards a modem banking System with significant improvements in profitability, capitalization, and assets quality. Despite of these observed improvements, the banking system is still associated with relatively
low profitability and capitalization, poor asset quality, and less liquidity, when benchmarking to 7 selected international renowned banks. One of the most impressive progresses has been the significant decrease in both outstanding NPLs balance and NPL ratio. However, it has noticed that the threat of NPLs problem to the economy as a whole remains unsolved.
This study has rationalized economic foundations for the banking reform in China being the principal-agent theory and the budgetary constraint theory. The performance of Chinese banks has been improved and the estimated effîciency level is consistently at 75% in terms of technical efficiency, cost efficiency and profit efficiency. Employing the method of Berger et al. (2005), this study has jointly analyzed the static, selection and dynamic effects of governance changes. Joint-stock
ownership has resulted in outstanding performance, while state ownership has been associated with low technical efficiency and profit efficiency but high cost efficiency.
Foreign banks are more profit efficient but less cost and technical efficient (static effects). Foreign investors have rationally made their investment decisions by
selecting more cost and technical efficient domestic banks, while less profitable domestic banks have been chosen for going public in line with government intension of reforming the unprofitable SOCBs (selection effects).
Attracting foreign strategic investors and encouraging banks going public are two major partial privatization strategies, which have been generally proved as effective
reform measures. The former tends to have positive impacts on technical efficiency and cost efficiency, while significant short-term gains in profit efficiency have faded in the long-term. The expected profit advantage of foreign ownership seems to take an even longer time to be realized. Going public strategy has resulted in performance
improvement in the long-term after short-term losses (dynamic effects).
We can not form a conclusion on whether the reform has succeeded, while what we can conclude is the reform is on the track with right direction. It is important to
construct good corporate governance, but it is more important to ensure the good governance functioning. If those deep-rooted problems, such as government
intervention and NPL problem, can not be dealt with properly in the near future, the chance of success is very small. Thus, our policy recommendations include
consolidating up-to-date reform achievements, improving bank's managerial and operational skills, and reducing state's share in banks to lessen government interventions.
Estimated efficiency is found to be sensitive to the differences in the definitions of outputs and inputs, especially in the presence of high level of NPLs. The income-based model is superior to the earning assets-based model in the estimation of technical efficiency. Similarly, profit efficiency appears to be more appropriate performance measures over cost efficiency. However, we suggest the use of multiple models and measures to reveal more valuable information. Moreover, in estimating cost function and alternative profit function, market average input prices are found to be more appropriate than banks' specific input prices
Hyperon Electromagnetic Properties in Two-Flavor Chiral Perturbation Theory
The pion mass dependence of hyperon electromagnetic properties is determined
using two-flavor heavy baryon chiral perturbation theory. Specifically we
compute chiral corrections to the charge radii, magnetic moments, and magnetic
radii of the spin one-half hyperons, as well as the charge radii, magnetic
moments, magnetic radii, electric quadrupole moments, and quadrupole radii of
the spin three-half hyperons. Results for the nucleon and delta are also
included. Efficacy of the two-flavor theory is investigated by analyzing the
role played by virtual kaons. For the electromagnetic properties of spin
one-half hyperons, kaon loop contributions are shown to be well described by
terms analytic in the pion mass squared. Similarly kaon contributions to the
magnetic moments of spin three-half hyperons are well described in the
two-flavor theory. The remaining electromagnetic properties of spin three-half
resonances can be described in two-flavor chiral perturbation theory, however,
this description fails just beyond the physical pion mass. For the case of
experimentally known hyperon magnetic moments and charge radii, we demonstrate
that chiral corrections are under reasonable control, in contrast to the
behavior of these observables in the three-flavor chiral expansion. The
formulae we derive are ideal for performing the pion mass extrapolation of
lattice QCD data obtained at the physical strange quark mass.Comment: 29 pages, 7 figures, v3: published versio
Hyperon Axial Charges in Two-Flavor Chiral Perturbation Theory
We use two-flavor heavy baryon chiral perturbation theory to investigate the
isovector axial charges of the spin one-half hyperons. Expressions for these
hyperon axial charges are derived at next-to-leading order in the chiral
expansion. We utilize phenomenological and lattice QCD inputs to assess the
convergence of the two-flavor theory, which appears to be best for cascades.Comment: 4 pages, 1 figures, published versio
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