48,787 research outputs found
On the Running of the Cosmological Constant in Quantum General Relativity
We present arguments that show what the running of the cosmological constant
means when quantum general relativity is formulated following the prescription
developed by Feynman.Comment: 5 page
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Persistence of UK Real Estate returns: a Markov chain analysis
The persistence of investment performance is a topic of perennial interest to investors. Efficient Markets theory tells us that past performance can not be used to predict future performance yet investors appear to be influenced by the historical performance in making their investment allocation decisions. The problem has been of particular interest to investors in real estate; not least because reported returns from investment in real estate are serially correlated thus implying some persistence in investment performance. This paper applies the established approach of Markov Chain analysis to investigate the relationship between past and present performance of UK real estate over the period 1981 to 1996. The data are analysed by sector, region and size. Furthermore some variations in investment performance classification are reported and the results are shown to be robust
-SDYM fields and heavenly spaces: II. Reductions of the -SDYM system
Reductions of self-dual Yang-Mills (SDYM) system for -bracket Lie
algebra to the Husain-Park (HP) heavenly equation and to
sl(N,{\boldmath{C}) SDYM equation are given. An example of a sequence of
chiral fields () tending for to a curved heavenly
space is found.Comment: 18 page
Task oriented nonlinear control laws for telerobotic assembly operations
The goal of this research is to achieve very intelligent telerobotic controllers which are capable of receiving high-level commands from the human operator and implementing them in an adaptive manner in the object/task/manipulator workspace. Initiatives by the authors at Integrated Systems, Inc. to identify and develop the key technologies necessary to create such a flexible, highly programmable, telerobotic controller are presented. The focus of the discussion is on the modeling of insertion tasks in three dimensions and nonlinear implicit force feedback control laws which incorporate tool/workspace constraints. Preliminary experiments with dual arm beam assembly in 2-D are presented
The effects of acceleration stress on human workload and manual control
The effects of +Gz stress on operator task performance and workload were assessed. Subjects were presented a two dimensional maze and were required to solve it as rapidly as possible (by moving a light dot through it via a trim switch on a control stick) while under G-stress at levels from +1 Gz to +6 Gz. The G-stress was provided by a human centrifuge. The effects of this stress were assessed by two techniques; (1) objective performance measures on the primary maze-solving task, and (2) subjective workload measures obtained using the subjective workload assessment technique (SWAT). It was found that while neither moderate (+3 Gz) nor high (+5 Gz and +6 Gz) levels of G-stress affected maze solving performance, the high G levels did increase significantly the subjective workload of the maze task
Generic approach for deriving reliability and maintenance requirements through consideration of in-context customer objectives
Not all implementations of reliability are equally effective at providing customer and user benefit. Random system failure with no prior warning or failure accommodation will have an immediate, usually adverse impact on operation. Nevertheless, this approach to reliability, implicit in measurements such as ‘failure rate’ and ‘MTBF’, is widely assumed without consideration of potential benefits of pro-active maintenance. Similarly, it is easy to assume that improved maintainability is always a good thing. However, maintainability is only one option available to reduce cost of ownership and reduce the impact of failure. This paper discusses a process for deriving optimised reliability and maintenance requirements through consideration of in-context
customer objectives rather than a product in isolation
Quantum Corrections to Newton's Law
We present a new approach to quantum gravity starting from Feynman's
formulation for the simplest example, that of a scalar field as the
representative matter. We show that we extend his treatment to a calculable
framework using resummation techniques already well-tested in other problems.
Phenomenological consequences for Newton's law are described.Comment: 7 pages, 1 figure; improved fig., refs;improved discussion;more
discussion; proo
Discharge chamber studies for mercury bombardment ion thrusters
Discharge chamber performance optimization for mercury bombardment ion thruster
On a low energy bound in a class of chiral field theories with solitons
A low energy bound in a class of chiral solitonic field theories related the
infrared physics of the SU(N) Yang-Mills theory is established.Comment: Plain Latex, 8 pages, no figure
After Regions: what next for local enterprise partnerships?
Standing out as an oddity in comparison to the convergence of policy across EU nations whereby the merits of regional apparatus – however defined – for administering development support appear to be accepted, the UK Government has abandoned England’s experiment with regionalism. Under the banner of localism, providing the thinnest of masks for swingeing public expenditure cuts, sub-national development activity (encompassing planning, regeneration, infrastructure development, enterprise support and spatial leadership) is in the throes of considerable economic shifts, policy flux and institutional upheaval (Ward & Hardy, 2012). This article attempts to address some of the questions posed in The regional lacuna: a preliminary map of the transition from Regional Development Agencies to Local Economic Partnerships (Pugalis, 2011) and helps to advance some of the points relating to the emerging sub-national development landscape published in recent issues of Regions (e.g. Bailey, 2011). The purpose is to take stock of policy developments underway by means of a post-regional sub-national review in order to outline the future development trajectory of Local Enterprise Partnerships
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