Dynamic simulation of task constrained of a rigid-flexible manipulator

A rigid-flexible manipulator may be assigned tasks in a moving environment where the winds or vibrations affect the position and/or orientation of surface of operation. Consequently, losses of the contact and perhaps degradation of the performance may occur as references are changed. When the environment is moving, knowledge of the angle α between the contact surface and the horizontal is required at every instant. In this paper, different profiles for the time varying angle α are proposed to investigate the effect of this change into the contact force and the joint torques of a rigid-flexible manipulator. The coefficients of the equation of the proposed rotating surface are changing with time to determine the new X and Y coordinates of the moving surface as the surface rotates

Thin-shell wormholes from the regular Hayward black hole

We revisit the regular black hole found by Hayward in $4-$dimensional static, spherically symmetric spacetime. To find a possible source for such a spacetime we resort to the non-linear electrodynamics in general relativity. It is found that a magnetic field within this context gives rise to the regular Hayward black hole. By employing such a regular black hole we construct a thin-shell wormhole for the case of various equations of state on the shell. We abbreviate a general equation of state by $p=\psi \left( \sigma \right)$ where $p$ is the surface pressure which is the function of the mass density ($\sigma$). In particular, a linear, logarithmic, Chaplygin, etc. forms of equations of state are considered. In each case we study the stability of the thin-shell against linear perturbations. We plot the stability regions by tuning the parameters of the theory. It is observed that the role of the Hayward parameter is to make the TSW more stable. Perturbations of the throat with small velocity condition is also studied. The matter of our TSWs, however, remains to be exotic.Comment: 7 pages 5 figures, extended versio

Why Government Bonds Are Sold by Auction and Corporate Bonds by Posted-Price Selling

When information is costly, a seller may wish to prevent prospective buyers from acquiring information, for the cost of information acquisition is ultimately borne by the seller. A seller can achieve the desired prevention of information acquisition through posted-price selling, by offering prospective buyers a discount that is such as to deter them from gathering information. No such prevention is possible in the case of an auction. Clearly, a discount is costly to the seller. We establish the result that the seller prefers posted-price selling when the cost of information acquisition is high, and auctions when it is low. We view corporate bonds as an instance of the former case, and government bonds as an instance of the latter.Government Bonds; Corporate Bonds; Auctions; Posted-Price Selling; Costly Information

Non-audit service fees and financial reporting quality: a meta-analysis

Auditing as a corporate governance mechanism has attracted considerable research attention. Because of the information asymmetry between corporate managers and outside shareholders, auditors are hired to provide independent assurance that financial statements are prepared following generally accepted accounting principles. The credibility of such assurance depends on the independence, both in fact and in appearance, of the auditor. Over the years, however, the independence of auditors has come under increased scrutiny because of their joint provision of both audit and non-audit services. A sizable literature on the impact of non-audit fees on financial reporting quality has developed. The evidence from this literature, however, remains inconclusive. This paper provides a meta-analysis of the available literature by assessing (a) the net effect of non-audit fees on financial reporting quality, and (b) whether there is homogeneity in the financial reporting quality proxies used in the extant literature. Findings suggest that the level of client-specific non-audit fees is associated with reduced financial reporting quality. However, the underlying studies used to conduct this meta-analysis are not homogenous

Feedback cooling of atomic motion in cavity QED

We consider the problem of controlling the motion of an atom trapped in an optical cavity using continuous feedback. In order to realize such a scheme experimentally, one must be able to perform state estimation of the atomic motion in real time. While in theory this estimate may be provided by a stochastic master equation describing the full dynamics of the observed system, integrating this equation in real time is impractical. Here we derive an approximate estimation equation for this purpose, and use it as a drive in a feedback algorithm designed to cool the motion of the atom. We examine the effectiveness of such a procedure using full simulations of the cavity QED system, including the quantized motion of the atom in one dimension.Comment: 22 pages, 17 figure