Generation of Fractional Factorial Designs

The joint use of counting functions, Hilbert basis and Markov basis allows to define a procedure to generate all the fractions that satisfy a given set of constraints in terms of orthogonality. The general case of mixed level designs, without restrictions on the number of levels of each factor (like primes or power of primes) is studied. This new methodology has been experimented on some significant classes of fractional factorial designs, including mixed level orthogonal arrays.Comment: 27 page

Effect of the Vacuum Energy Density on Graviton Propagation

It is known that the value L of the vacuum energy density affects the propagation equation for gravitons: A mass term appears in the propagation equation, such that m^2=-L. As a consequence, the polarization states of gravitons also change. This effect of the L-term has been confirmed by recent calculations in a curved background, which is the only proper setting, since solutions of the classical Einstein equations in the presence of a L-term represent a space with constant curvature. A real value for the mass (when L<0) will show up as a slight exponential damping in the gravitational potential, which is however strongly constrained by astronomical data. The consequences of an imaginary mass (for L>0) are still unclear; on general grounds, one can expect the onset of instabilities in this case. This is also confirmed by numerical simulations of quantum gravity which became recently available. These properties gain a special interest in consideration of the following. (1) The most recent cosmological data indicate that L is positive and of the order of 0.1 J/m^3. Is this value compatible with a stable propagation of gravitons? (2) The answer to the previous question lies perhaps in the scale dependence of the effective value of L. L may be negative at the small distance/large energy scale at which the quantum behavior of gravitational fields and waves becomes relevant. Furthermore, local contributions to the vacuum energy density (in superconductors in certain states, and in very strong static electromagnetic fields) can change locally the sign of L, and so affect locally the propagation and the properties of gravitons. The graviton wavefunction, for different values of the parameters, may be characterized by superluminal phase velocity or by unitarity only in imaginary valued time.Comment: CP699, Space Technology and Applications International Forum-STAIF 2004, proceedings published by AIP and edited by M.S. El-Gen

Algebraic strata for non symmetrical orthogonalfractional factorial designs and application

La Matematica e le sue Applicazioni - Politecnico DIMAT n.01/201

Flussi turistici in Piemonte: prime valutazioni degli eventi con i dati giornalieri dei flussi turistici nel 2008

Piemonte e Turismo - Scenari Internazionali, trend dei mercati e prodotti turistici piemontes

Algebraic strata for non symmetrical orthogonalfractional factorial designs and application

La Matematica e le sue Applicazioni - Politecnico DIMAT n.01/201

2-level fractional factorial designs which are the union of non trivial regular designs

Every fraction is a union of points, which are trivial regular fractions. To characterize non trivial decomposition, we derive a condition for the inclusion of a regular fraction as follows. Let $F = \sum_\alpha b_\alpha X^\alpha$ be the indicator polynomial of a generic fraction, see Fontana et al, JSPI 2000, 149-172. Regular fractions are characterized by $R = \frac 1l \sum_{\alpha \in \mathcal L} e_\alpha X^\alpha$, where $\alpha \mapsto e_\alpha$ is an group homeomorphism from $\mathcal L \subset \mathbb Z_2^d$ into $\{-1,+1\}$. The regular $R$ is a subset of the fraction $F$ if $FR = R$, which in turn is equivalent to $\sum_t F(t)R(t) = \sum_t R(t)$. If $\mathcal H = \{\alpha_1 >... \alpha_k\}$ is a generating set of $\mathcal L$, and $R = \frac1{2^k}(1 + e_1X^{\alpha_1}) ... (1 + e_kX^{\alpha_k})$, $e_j = \pm 1$, $j=1 ... k$, the inclusion condition in term of the $b_\alpha$'s is % \begin{equation}b_0 + e_1 b_{\alpha_1} + >... + e_1 ... e_k b_{\alpha_1 + ... + \alpha_k} = 1. \tag{*}\end{equation} % The last part of the paper will discuss some examples to investigate the practical applicability of the previous condition (*). This paper is an offspring of the Alcotra 158 EU research contract on the planning of sequential designs for sample surveys in tourism statistics.Comment: Presented by R. Fontana at the DAE 2007 Conference, The University of Memphis, November 2, 200

Una cross-country analysis sulle strategie competitive delle società di calcio professionistiche:i casi Manchester United F.C. e Juventus F.C.

Fino a qualche anno fa poteva sembrare piuttosto strano proporre una tesi di laurea in economia che trattasse del business collegato alle società calcistiche o, in generale, allo sport. Ancora oggi, in realtà, gli aspetti finanziari ed economici legati all’attività sportiva sono considerati da molti con sufficienza, come se fossero intrinsecamente secondari rispetto agli aspetti atletici e sociali, che al contrario sono posti al centro delle preoccupazioni primarie di chi fa o organizza sport professionistico. Nonostante nel linguaggio utilizzato dai manager e dagli economisti aziendali lo sport agonistico venga comunemente utilizzato come metafora della competizione a livello economico, ricorrendo spesso all’uso dei termini strategia, tattica, risorse, competenze specifiche e generiche etc., tuttavia si fa ancora fatica ad ritenere lo sport professionistico come un settore economico degno di autonoma e specifica considerazione

Servizio e centralità del cliente nel settore fotovoltaico. Il caso Conergy Italia

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Adenolipoma della trachea. Descrizione di un caso trattato mediante resezione-anastomosi tracheale.

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