117,145 research outputs found
Risk Regulation and the Faces of Uncertainty
Dr. Walker addresses the difficulty of regulators\u27 working with potentially inaccurate information and clarifies related aspects of decision making by presenting a taxonomy for the kinds of uncertainty inherent in necessarily incomplete data
Laboratory studies of interplanetary dust
Interplanetary dust particles (IDPs) are a form of primitive extraterrestrial material. In spite of the formidable experimental problems in working with particles that are too small to be seen with the naked eye, it has proven possible to obtain considerable information concerning their properties and possible origins. Dust particles collected in the stratosphere were reviewed. These particles are the best available samples of interplanetary dust and were studied using a variety of analytical techniques
Real-time flutter identification
The techniques and a FORTRAN 77 MOdal Parameter IDentification (MOPID) computer program developed for identification of the frequencies and damping ratios of multiple flutter modes in real time are documented. Physically meaningful model parameterization was combined with state of the art recursive identification techniques and applied to the problem of real time flutter mode monitoring. The performance of the algorithm in terms of convergence speed and parameter estimation error is demonstrated for several simulated data cases, and the results of actual flight data analysis from two different vehicles are presented. It is indicated that the algorithm is capable of real time monitoring of aircraft flutter characteristics with a high degree of reliability
Affine Hecke algebras and generalisations of quiver Hecke algebras for type B
We define and study cyclotomic quotients of affine Hecke algebras of type B.
We establish an isomorphism between direct sums of blocks of these algebras and
a generalisation, for type B, of cyclotomic quiver Hecke algebras which are a
family of graded algebras closely related to algebras introduced by Varagnolo
and Vasserot. Inspired by the work of Brundan and Kleshchev we first give a
family of isomorphisms for the corresponding result in type A which includes
their original isomorphism. We then select a particular isomorphism from this
family and use it to prove our result.Comment: 37 page
Affine Hecke algebras of type D and generalisations of quiver Hecke algebras
We define and study cyclotomic quotients of affine Hecke algebras of type D.
We establish an isomorphism between (direct sums of blocks of) these cyclotomic
quotients and a generalisation of cyclotomic quiver Hecke algebras which are a
family of Z-graded algebras closely related to algebras introduced by Shan,
Varagnolo and Vasserot. To achieve this, we first complete the study of
cyclotomic quotients of affine Hecke algebras of type B by considering the
situation when a deformation parameter p squares to 1. We then relate the two
generalisations of quiver Hecke algebras showing that the one for type D can be
seen as fixed point subalgebras of their analogues for type B, and we carefully
study how far this relation remains valid for cyclotomic quotients. This allows
us to obtain the desired isomorphism. This isomorphism completes the family of
isomorphisms relating affine Hecke algebras of classical types to
(generalisations of) quiver Hecke algebras, originating in the famous result of
Brundan and Kleshchev for the type A.Comment: 26 page
Britain's New Deal and the Next Round of U.S. Welfare Reform
The United States will begin another round of debate on welfare reform during the 107th Congress, which convened in January 2001. The new congress and administration must decide on reauthorization of funding for Temporary Assistance for Needy Families, the program established in 1996 as a replacement for Aid to Families with Dependent Children. Among other things, the reauthorization debate will focus on issues of program funding, rationalization, performance, best practice, and direction. This paper argues that all phases of this debate would benefit from more widespread understanding and appreciation of the British Labour government's welfare reform program, including both the New Deal welfare-to-work programs and related changes in benefits and coverage. This paper reviews the ideology, strategy, and implementation of British innovations with regard to links to U.S. reforms and as a source of new perspectives and ideas for the reauthorization debate.
E-learning as a Vehicle for Knowledge Management
Nowadays, companies want to learn from their own experiences and to be able to enhance that experience with best principles and lessons learned from other companies. Companies emphasise the importance of knowledge management, particularly the relationship between knowledge and learning within an organisation. We feel that an e-learning environment may contribute to knowledge management on the one hand and to the learning need in companies on the other hand. In this paper, we report on the challenges in designing and implementing an e-learning environment. We identify the properties from a pedagogical view that should be supported by an e-learning environment. Then, we discuss the challenges in developing a system that includes these properties
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