92,611 research outputs found
Smoke and Shadows: Rendering and Light Interaction of Smoke in Real-Time Rendered Virtual Environments
Realism in computer graphics depends upon digitally representing what we see in the world with careful attention to detail, which usually requires a high degree of complexity in modelling the scene. The inevitable trade-off between realism and performance means that new techniques that aim to improve the visual fidelity of a scene must do so without compromising the real-time rendering performance. We describe and discuss a simple method for realistically casting shadows from an opaque solid object through a GPU (graphics processing unit) based particle system representing natural phenomena, such as smoke
Physics of the Pseudogap State: Spin-Charge Locking
The properties of the pseudogap phase above Tc of the high-Tc cuprate
superconductors are described by showing that the Anderson-Nambu SU(2) spinors
of an RVB spin gap 'lock' to those of the electron charge system because of the
resulting improvement of kinetic energy. This enormously extends the range of
the vortex liquid state in these materials. As a result it is not clear that
the spinons are ever truly deconfined. A heuristic description of the
electrodynamics of this pseudogap-vortex liquid state is proposed.Comment: Submitted to Phys Rev Letter
Capital Structure and Investment Behaviour of Malaysian Firms in the 1990s: A Study of Corporate Governance before the Crisis
This is an empirical study analyzing the corporate finance and governance structure in Malaysia before and after the financial crisis of 1997, utilizing the agency cost approach. The contribution of this paper is to link the corporate governance mechanism with the role of banks and corporate ownership structure taking into account the institutional framework and historical background of the Malaysian financial system. Based on data for 375 non-financial KLSE (Kuala Lumpur Stock Exchange) listed companies during fiscal years 1995-99, our analysis is organized into three parts. Section 2 outlines characteristics of corporate finance in Malaysia in the 1990s using aggregated time-series data. Section 3 examines determinants of capital structure via cross-sectional regressions in terms of dependency on banks, availability of internal funds, ownership concentration, ethnic ownership structure, industry effects, etc. And in section 4, we estimate simple investment functions with panel data in order to examine the effects of debt financing on corporate investments before the crisis. Empirical results show that the commitment of banks to finance corporate debt as well as lending obviously increased debt ratios. Ownership concentration mitigates conflict between managers and owners. Foreign ownership also contributed to a reduction in the agency costs of equity financing. However, increasing ownership by native Malays (Bumiputera), both the direct and indirect holding of corporate shares, played no significant role in disciplining corporate management. Finally, high dependency on debt led to excessive corporate investment before the crisis. These results imply that the concentration of risks on the banking sector and social policy advocating the dispersion of corporate ownership weakened the corporate governance mechanism, thereby exacerbating the distress of Malaysia's corporate sector during the financial crisis.
Monotonicity and logarithmic convexity relating to the volume of the unit ball
Let stand for the volume of the unit ball in for
. In the present paper, we prove that the sequence
is logarithmically convex and that the sequence
is strictly
decreasing for . In addition, some monotonic and concave properties of
several functions relating to are extended and generalized.Comment: 12 page
Maximum solutions of normalized Ricci flows on 4-manifolds
We consider maximum solution , , to the normalized
Ricci flow. Among other things, we prove that, if is a smooth
compact symplectic 4-manifold such that and let
, be a solution to (1.3) on whose Ricci curvature
satisfies that and additionally , then there exists an , and a sequence of points
, , satisfying that, by passing to a
subsequence, , in the -pointed
Gromov-Hausdorff sense for any sequence , where
, , are complete complex hyperbolic orbifolds
of complex dimension 2 with at most finitely many isolated orbifold points.
Moreover, the convergence is in the non-singular part of
and
, where
(resp. ) is the Euler characteristic (resp. signature) of
.Comment: 23 page
Phased array antenna beamforming using optical processor
The feasibility of optical processor based beamforming for microwave array antennas is investigated. The primary focus is on systems utilizing the 20/30 GHz communications band and a transmit configuration exclusively to serve this band. A mathematical model is developed for computation of candidate design configurations. The model is capable of determination of the necessary design parameters required for spatial aspects of the microwave 'footprint' (beam) formation. Computed example beams transmitted from geosynchronous orbit are presented to demonstrate network capabilities. The effect of the processor on the output microwave signal to noise quality at the antenna interface is also considered
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