Control technology development

The main objectives of the control technology development task are given in the slide below. The first is to develop control design techniques based on flexible structural models, rather than simple rigid-body models. Since large space structures are distributed parameter systems, a new degree of freedom, that of sensor/actuator placement, may be exercised for improving control system performance. Another characteristic of large space structures is numerous oscillatory modes within the control bandwidth. Reduced-order controller design models must be developed which produce stable closed-loop systems when combined with the full-order system. Since the date of an actual large-space-structure flight is rapidly approaching, it is vitally important that theoretical developments are tested in actual hardware. Experimental verification is a vital counterpart of all current theoretical developments

The quality of public finances and economic growth

Improving the quality of public finances (QPF) has become a new focus for European policy makers. This focus is largely a response to preparing the European economies for the dual challenge of ageing populations and increased exposure to global competition. At the EU level, the Stability and Growth Pact and the Lisbon Strategy for Growth and Jobs provide, in principle, the appropriate tools for fostering a greater role of QPF in fiscal surveillance but this has not yet fully materialised in practice. This is partly because a broad-based conceptual framework on what makes up QPF has been missing. This paper attempts to close this gap by developing a multi-dimensional approach on QPF. Moreover, it reviews how EU Member States fare in each dimension and summarises empirical findings on the links between QPF and growth, including through a growth-accounting approach using discriminant analysis.Public finances, fiscal policy, public spending, fiscal governance, expenditure efficiency, revenue systems, growth accounting, Barrios, Schaechter

Gauging by numbers: A first attempt to measure the quality of public finances in the EU

Ensuring high quality of public finances (QPF) with a view to supporting long-term economic growth has gained new urgency as the room for fiscal manoeuvre has shrunk in light of the current crisis. To more systematically analyse QPF and compare developments across countries and over time, a greater focus on identifying and developing comparable QPF indicators is needed. This paper provides a first attempt in this respect. Based on the view that QPF is a multi-dimensional concept, it creates composite indicators for twelve areas of public finances that are linked to long-term economic growth. While the proposed alternative calculation methods yield relatively robust results and findings are in line with conventional wisdom, due to data problems the composite indicators should only be seen as a useful starting point for identifying a country's main strengths and weaknesses in QPF. This would need to be complemented by qualitative analysis that also accounts for country and other specificities. JEL classification: E62, H11, H50, H52, H60Quality of public finances, public finances, fiscal policy, long-term economic growth, public expenditure, public revenue, fiscal governance, Barrios, Schaechter

Adaptive Filtering for Large Space Structures: A Closed-Form Solution

In a previous paper Schaechter proposes using an extended Kalman filter to estimate adaptively the (slowly varying) frequencies and damping ratios of a large space structure. The time varying gains for estimating the frequencies and damping ratios can be determined in closed form so it is not necessary to integrate the matrix Riccati equations. After certain approximations, the time varying adaptive gain can be written as the product of a constant matrix times a matrix derived from the components of the estimated state vector. This is an important savings of computer resources and allows the adaptive filter to be implemented with approximately the same effort as the nonadaptive filter. The success of this new approach for adaptive filtering was demonstrated using synthetic data from a two mode system

From growth physiology to systems biology

As it focuses on the integrated behavior of the entire cell, systems biology is a powerful extension of growth physiology. Here, I briefly trace some of the origins of modern-day bacterial growth physiology and its relevance to systems biology. I describe how growth physiology emerged from the foggy picture of the growth curve as a self-contained entity. For this insight, we can thank Henrici, Hershey, Monod, Maaløe, and others. As a result of their work, growth rate is understood to be the unitary manifestation of the response to nutritional conditions and to the control condition for studies on the effect of environmental stresses. For this response to be usefully reproducible, cultures must be in the steady state known as balanced growth. I point out that present-day experimenters are not always aware of this imperative and thus do not always use conditions that ensure the balanced growth of their control cultures. [Int Microbiol 2006; 9(3):157-161

Study to develop gradiometer techniques

The primary goal of the current gravity gradiometer research at Stanford has been to establish the feasibility of using a gravity gradiometer with 1 E accuracy, as the primary sensor in various applications. The two applications considered here in detail are geodesy missions and inertial navigation systems. Preliminary sections on gravity models and gravity gradiometer bias estimation are also included

The era of microbiology: a Golden Phoenix

The discoveries over the last decade have demonstrated that microbiology is a central scientific discipline with practical applications in agriculture, medicine, bioremediation, biotechnology, engineering, and other fields. It is clear that the roles of microbes in nature are so diverse that the process of mining this genetic variation for new applications will continue long into the future. Moreover, the rapid rate of microbial evolution ensures that there will be no permanent solution to agricultural, medical, or environmental problems caused by microbes. These problems will demand a continual stream of creative new approaches that evolve along with the microbes. Thus, the excitement of this field will continue long into the future. However, these opportunities and imperatives demand a deep understanding of basic microbial physiology, genetics, and ecology. Major challenges that lay ahead are to impart the broad training needed to entice and enable the next generation of microbiologists, and to educate the public and government representatives about the continued and critical importance of this field for health and the economy. [Int Microbiol 2006; 9(1):1-7

Spacecraft drag-free technology development: On-board estimation and control synthesis

Estimation and control methods for a Drag-Free spacecraft are discussed. The functional and analytical synthesis of on-board estimators and controllers for an integrated attitude and translation control system is represented. The framework for detail definition and design of the baseline drag-free system is created. The techniques for solution of self-gravity and electrostatic charging problems are applicable generally, as is the control system development

Distributed control of large space structures

Theoretical developments and the results of laboratory experiments are treated as they apply to active attitude and vibration control, as well as static shape control. Modern control theory was employed throughout as the method for obtaining estimation and control laws