11,119 research outputs found
On supersymmetry breaking and the Dijkgraaf-Vafa conjecture
We investigate the Dijkgraaf-Vafa proposal when supersymmetry is broken. We
consider U(N) SYM with chiral adjoint matter where the coupling constants in
the tree-level superpotential are promoted to chiral spurions. The holomorphic
part of the low-energy glueball superpotential can still be analyzed. We
compute the holomorphic supersymmetry breaking contributions using methods of
the geometry underlying the N=1 effective gauge theory viewed as a Whitham
system. We also study the change in the effective glueball superpotential using
perturbative supergraph techniques in the presence of spurions.Comment: 24 pages, LaTeX; minor changes, one reference added, version to
appear in JHE
Efficiency and Equilibrium when Preferences are Time-Inconsistent
We consider an exchange economy with time-inconsistent consumers whose preferences are additively separable. When these consumers trade in a sequence of markets, their time-inconsistency may introduce a non-convexity that gives them an incentive to trade lotteries. If there are many consumers, competitive equilibria with and without lotteries exist. The existence of symmetric equilibria may require lotteries. Symmetric equilibria that do not require lotteries are generically locally unique. Allocations that are Pareto efficient at the initial date are also renegotiation-proof. Competitive equilibria are Pareto efficient in this sense, and for generic endowments, if and only if preferences are locally homothetic. For non-homothetic preferences, the introduction of lottery markets has an ambiguous impact on the equilibrium welfare of consumers at the initial date.Dynamic inconsistency, competitive equilibrium, lotteries, generic inefficiency.
INFLUENCE OF UNCERTAINTIES ON ROTATING FLEXIBLE SHAFT SUSPENDED BY 4-AXIS RADIAL ACTIVE MAGNETIC BEARINGS \ub5-SYNTHESIS AND LOOP-SHAPING-DESIGN
This paper shows a comparison about dynamic behavior of a rotating shaft when it is suspended by 4-axis radial active magnetic bearing system. The active magnetic suspension is obtained by two different controllers which realize the robust stability and robust performance. The control systems used are \ub5-synthesis and loop shaping design procedure.
Each of these controllers is characterized by fourinput and four output signals and the
introduction of uncertainties on displacement gain and current gain is justified by the simple fact that during the time the component which constitutes these gains can be subjected to torn and worn which can lead the entire system to instability phenomena. The inputs are the
feedbacks of four displacement components relative to the four axis of radial active magnetic bearing while the outputs are the control current injected in the plant in order to provide the control of position of two section under the monitoring of ideal sensors. An ideal sensor here is meant to be able to capture small displacements and without presence of noise. The advantages of a four input controller is the absence of velocity components which are present
in the state vector such that no observer and speedsensors are need to build a feedback. The comparison of the performances is made through the introduction of same weighting function for the two control system. The weighting functions are introduced in order to define the required performances for the position and control signals. The results are produced by simulations tracking of reference and disturbance rejection are tested in order to provide elements useful to implement the goal of this paper. All simulations and results are performed by MATLab
INFLUENZA SUL COMPORTAMENTO DINAMICO DI UN ROTORE SOSPESO ATTRAVERSO CUSCINETTI MAGNETICI ATTIVI MEDIANTE \u3bc-SYNTHESIS E LOOP-SHAPING DESIGN
In questo lavoro viene effettuato un confronto sul comportamento dinamico di un albero rotante quando \ue8 sospeso attraverso un sistema di due cuscinetti magnetici ciascuno costituito da due assi.
Le sospensione magnetica attiva \ue8 ottenuta elaborando due diversi sistemi di controllo che realizzano la stabilit\ue0 del rotore conferendo a quest\u2019ultimo delle prestazioni robuste nel mantenimento degli spostamenti entro certi margini prestabiliti. Ognuno di questi sistemi di controllo \ue8 caratterizzato da otto ingressi e quattro uscite con la presenza di incertezze sul guadagno spostamento e guadagno di corrente; ci\uf2 \ue8 giustificato dal semplice fatto che gli apparati elettronici possono usurarsi con il continuo uso nel tempo inducendo il rotore a stati di instabilit\ue0 durante un normale funzionamento. I risultati prodotti sono mostrati attraverso le simulazioni in ambiente MATLab dove vengono testate le capacit\ue0 del rotore di eliminare il disturbo e di seguire un riferiment
Multibody numerical simulation for vehicle \u2013 pedestrian crash test and analysis of characteristic parameters
Fine tuning of track impact parameter resolution of the DELPHI detector
The fine tuning of the charged track impact parameter resolution for data and simulation in the DELPHI detector at LEP is described. This tuning was implemented in the software for the tagging of hadrons and has been applied in many precise measurements
Higgs boson couplings: Measurements and theoretical interpretation
This report will review the Higgs boson properties: the mass, the total width
and the couplings to fermions and bosons. The measurements have been performed
with the data collected in 2011 and 2012 at the LHC accelerator at CERN by the
ATLAS and CMS experiments. Theoretical frameworks to search for new physics are
also introduced and discussed.Comment: 67 pages, 23 figure
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