Twisted Bundle On Quantum Torus and BPS States in Matrix Theory

Following the recent work of Connes, Douglas and Schwarz, we study the M(atrix) model compactified on a torus with a background of the three-form field. This model is given by a super Yang-Mills theory on a quantum torus. To consider twisted gauge field configurations, we construct twisted U(n) bundles on the quantum torus as a deformation of its classical counterpart. By properly taking into account membranes winding around the light-cone direction, we derive from the M(atrix) model the BPS spectrum which respects the full SL(2,Z)*SL(2,Z) U-duality in M theory.Comment: 14 pages, no figure. minor modification mad

Model-based controller design for a plastic film extrusion process

This paper reports the development and implementation of a model-based cross-directional controller for plastic film extrusion and other web-forming processes. The controller design has a similar structure to that of internal model control (IMC) with the addition of an observer whose gain is designed to minimise process and model mis-match. The observer gain is obtained by solving a multi-objective optimisation through the application of a genetic algorithm and simulation results are presented in this paper demonstrating improvements that can be achieved by the proposed controller over two existing CD controllers

Modeling and control of a plastic film manufacturing web process

This paper is concerned with the modelling of aplastic film manufacturing process and the development and implementation of a model-based Cross-Directional (CD) controller. The model is derived from first-principles and some empirical relationships. The final validated nonlinear model could provide a useful off-line platform for developing control and monitoring algorithms.A new controller is designed which has a similar structureto that of Internal Model Control (IMC) with the addition ofan observer whose gain is designed to minimise process andmodel mis-match. The observer gain is obtained by solving amulti-objective optimisation problem through the application of a genetic algorithm. The controller is applied to the nonlinear model and simulation results are presented demonstrating improvements that can be achieved by the proposed controller over two existing CD controllers

A control and monitoring oriented model of a film manufacturing process

This paper describes the development of a control and monitoring oriented model of a plastic film manufacturing process. The model is mainly derived from first-principles and has been implemented in the Matlab/Simulink dynamic simulation environment. The development of the model forms the first phase of a project that aims to develop a nonlinear sub-space based monitoring, fault detection and trouble shooting system for the film manufacturing process

D0-branes in an H-field Background and Noncommutative Geometry

It is known that if we compactify D0-branes on a torus with constant B-field, the resulting theory becomes SYM theory on a noncommutative dual torus. We discuss the extension to the case of a H-field background. In the case of constant H-field on a three-torus, we derive the constraints to realize this compactification by considering the correspondence to string theory. We carry out this work as a first step to examine the possibility to describe transverse M5-branes in Matrix theory.Comment: 15 pages, LaTeX; some comments added, typos corrected, to appear in Nucl. Phys.

Gauge Bundles and Born-Infeld on the Noncommutative Torus

In this paper, we describe non-abelian gauge bundles with magnetic and electric fluxes on higher dimensional noncommutative tori. We give an explicit construction of a large class of bundles with nonzero magnetic 't Hooft fluxes. We discuss Morita equivalence between these bundles. The action of the duality is worked out in detail for the four-torus. As an application, we discuss Born-Infeld on this torus, as a description of compactified string theory. We show that the resulting theory, including the fluctuations, is manifestly invariant under the T-duality group SO(4,4;Z). The U-duality invariant BPS mass-formula is discussed shortly. We comment on a discrepancy of this result with that of a recent calculation.Comment: 22 pages, LaTeX2e. Small errors correcte

Dielectric D0-Branes in Near-Horizon D-Brane Backgrounds and D-Strings under Electric RR Fluxes

Using the nonabelian Dirac-Born-Infeld action with the Wess-Zumino term that is constructed in consistent with T duality we examine the Myers dielectric effect for multiple D0-branes in the near-horizon geometry of D4-branes. The effect in the curved spacetime is also confirmed by the dual formulation based on the abelian Dirac-Born-Infeld action of a D2-brane. Putting a system of muliple D-strings in the external electric RR five-form flux, we construct a noncommutative non-BPS solution where the D-strings expand into a spherical D3-brane. We discuss the external field dependence of the funnel-like or wormhole solution.Comment: 11 pages, LaTeX2e, no figure

The impact of governance and ownership structure on disclosure patterns transcending major regulatory change in Malaysia

The purpose of this study is to investigate the extent of voluntary disclosures between 2006 and 2009 that transcends major regulatory and governance changes in Malaysia and to assess the association between strength of corporate governance structure, and ownership structure on the extent of voluntary disclosures of Malaysian listed firms over that period. The average level of voluntary disclosure within the annual reports of sample firms increased over the two periods. Further, the extent of voluntary disclosure is significantly positively associated with strength of corporate governance structure in both 2006 and 2009. Firms with concentrated ownership structure are associated with more extensive voluntary disclosures. These findings highlight the importance of an effective governance regime and concentrated ownership structure in reducing information asymmetry and agency costs and thereby enhancing the level of voluntary disclosures. These findings also have practical implications for policy-makers, analysts, auditors and regulators in Malaysia as well as East Asian countries

Corporate governance and different types of voluntary disclosure

Purpose – The purpose of this paper is to investigate the impact of corporate governance on voluntary disclosure of different types of information in annual reports of Malaysian listed firms. Design/methodology/approach – A linear regression model is used to test the association between the level of voluntary disclosure of five key information categories and corporate governance. The sample consists of 100 firms over three different socio-economic periods: 1996, 2001 and 2006. Findings – There are significant increases in all the key information categories with better communication most pronounced between 1996 and 2001, and a noticeably lower level of communication growth between 2001 and 2006. The strength of a firm’s corporate governance structure clearly influences the voluntary disclosure of information relating to corporate and strategic directions, directors and senior management, financial and capital markets, forward-looking projections and corporate social responsibility in 2001 and 2006. Research limitations/implications – The use of a governance index to arrive at an overall corporate governance score has the potential to mask major underlying relationships of individual governance attributes. The use of the self-constructed disclosure indices may also omit certain information items that are employed in other prior studies. Moreover, the different categories of disclosures are solely constructed on the information disclosed in the annual reports without considering the alternative avenues.Practical implications – The results will assist regulators and policy-makers to better understand the impact of corporate governance on the voluntary disclosure of different types of corporate information in Malaysia. Originality/value – This study generates evidence of the changing scene of management voluntary disclosure practices embedded in the corporate governance framework in a developing country with an emerging capital market