Multi-spacecraft optimal interferometric imaging.

We consider a multi-spacecraft distributed formation consisting of several free-flying spacecraft, each carrying a relatively small telescope (compared to the system baseline). As the spacecraft execute maneuvers, it is supposed that the collected beams from selected pairs of telescopes are interfered to produce a continuous sequence of measurements to form interferometric images. The potential of a space borne interferometer is relevant to missions being planned by NASA under the Origins program. This work focuses on the design of a free flying space borne interferometer with the goal of attaining improved image quality for the de-convolved images produced by interferometry. A formulation of the image acquisition process relevant to the multi-spacecraft formation leads to the development of an image quality metric based on the evolving modulation transfer function (MTF) of the system and the signal-to-noise ratio. Additionally, the optimal imaging problem is discussed based on analysis of the system's resolution disc in the spatial frequency domain. The problem is then formulated as a coverage problem in which several solutions are presented as coverage algorithms. The performance of these algorithms is assessed using a simulation tool developed using MatlabRTM. Finally, we implement image processing techniques embedded within the image acquisition process with the goal of improving the quality of the de-convolved image.Ph.D.Aerospace engineeringApplied SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125607/2/3208415.pd

An Examination of the Role of Audit Committees in the Saudi Arabian Corporate Sector

Based on a series of research interviews with academics and external and internal auditors, this paper examines the role of audit committees in the Saudi Arabian corporate sector. The interviewees expressed concerns about the terms of reference of audit committees and the scope of work undertaken. The independence of audit committees was called into question, as was the expertise of audit committee members. Audit committees had failed to establish close working relationships with either internal or external auditors. A particular criticism was that the requirements for audit committees as set out in Ministerial Resolve 903 lacked clarity. It was suggested that the Ministry of Commerce should issue further regulations and guidance in order to improve the effectiveness of audit committees and to enhance corporate governance in Saudi Arabia. Copyright Blackwell Publishers Ltd 2002.

Internal Auditor Perceptions on Audit Committee Interactions: a qualitative study in Malaysian public corporations

Audit committees (AC) and the internal audit function (IAF) are two key corporate governance mechanisms. The primary objective of this study is to provide insights into internal auditors' perceptions of their interactions with AC members in Malaysia. The paper thus contributes to the extant literature by providing additional evidence from a South-east Asian country which is recognised as being characterised with a high power distance culture and a developing capital market. The findings are based on in-depth interviews of the heads of the internal audit function (HIAFs) from 11 publicly listed companies. The results indicate infrequent informal communications and limited private meetings between the HIAFs and ACs, and a need for clear reporting lines. Further, ACs are seen to be held in high esteem for their authority and are expected to take on greater leadership in the inquiry of management's decision-making. These findings highlight the importance of the leadership role of ACs in supporting the IAF. Copyright (c) 2007 The Authors; Journal compilation (c) 2007 Blackwell Publishing Ltd.