1,234 research outputs found

    On the Existence of Consistent Price Systems

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    We formulate a sufficient condition for the existence of a consistent price system (CPS), which is weaker than the conditional full support condition (CFS) introduced by Guasoni, Rasonyi, and Schachermayer [Ann. Appl. Probab., 18(2008), pp. 491-520] . We use the new condition to show the existence of CPSs for certain processes that fail to have the CFS property. In particular this condition gives sufficient conditions, under which a continuous function of a process with CFS admits a CPS, while the CFS property might be lost.Comment: To appear in "Stochastic Analysis and Applications". Keywords: Consistent pricing systems, No-arbitrage, Transaction costs, Full support, Conditional Full Support, Stability under Composition with Continuous Function

    Pluripotential Theory and Convex Bodies: A Siciak-Zaharjuta theorem

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    We work in the setting of weighted pluripotential theory arising from polynomials associated to a convex body PP in (R+)d({\bf R}^+)^d. We define the {\it logarithmic indicator function} on Cd{\bf C}^d: HP(z):=supJPlogzJ:=supJPlog[z1j1zdjd]H_P(z):=\sup_{ J\in P} \log |z^{ J}|:=\sup_{ J\in P} \log[|z_1|^{ j_1}\cdots |z_d|^{ j_d}] and an associated class of plurisubharmonic (psh) functions: LP:={uPSH(Cd):u(z)HP(z)=0(1), z}.L_P:=\{u\in PSH({\bf C}^d): u(z)- H_P(z) =0(1), \ |z| \to \infty \}. We first show that LPL_P is not closed under standard smoothing operations. However, utilizing a continuous regularization due to Ferrier which preserves LPL_P, we prove a general Siciak-Zaharjuta type-result in our PP-setting: the weighted PP-extremal function VP,K,Q(z):=sup{u(z):uLP, uQ on K}V_{P,K,Q}(z):=\sup \{u(z):u\in L_P, \ u\leq Q \ \hbox{on} \ K\} associated to a compact set KK and an admissible weight QQ on KK can be obtained using the subclass of LPL_P arising from functions of the form 1degP(p)logp\frac{1}{deg_P(p)}\log |p| (appropriately normalized)

    Numerical Analysis of a Two-Phase Flow (Oil and Gas) in a Horizontal Separator used in Petroleum Projects

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    In the present paper, two-phase three-dimensional turbulent flow simulations are carried out by applying computational fluid dynamics (CFD) technique to the internal flow of a horizontal separator that is used in petroleum industry. Two different geometries are considered; the separator with a straight plate at the top and the separator with the straight plate on the side of the separator. Effects of the location, distance between the inlet of the separator and the diverter plate and inlet velocity on the separation efficiency are investigated by employing the standard k- ε turbulence model. For these purposes, three different distances between the straight diverter plate and the inlet to the separator (0.1 m, 0.15 m and 0.2 m) and four different velocities (0.25 m/s, 0.5 m/s, 0.75 m/s, and 1 m/s) are taken into account by means of Euler mixture model. It is revealed that the maximum separation efficiency is 99.772% when the mixture enters the separator from the top with the inlet velocity of 0.25 m/s and the plate is located 0.2 m away from the inlet section of the separator. An inverse correlation is detected between the inlet velocity and the efficiency of the separation since increasing the inlet velocity decreases the efficiency of the separation

    Sécularisation, Démocratisation et Monde musulman: Processus de changement

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    L'AFEMOTI a organisé les 25-26 novembre 2002, en collaboration avec l'Institut norvégien des relations internationales, et l'UNESCO dans le cadre du programme de ce dernier concernant "Gestion des transformations sociales" (MOST), un colloque international sur « Sécularisation, Démocratisation et Monde musulman : Processus de changement ». Un point de vue assez largement répandu dans les opinions publiques et les médias occidentaux affirme l'incapacité des sociétés musulmanes d'entrer dans la modernité et, notamment, d'acclimater en leur sein la sécularité et la démocratie, qui en sont des caractéristiques majeures. La notion de sécularité et les processus de sécularisation ont été privilégiés ici par rapport au concept de laïcité. Il s'agit moins de discuter des manières dont les institutions et les acteurs politiques et étatiques ­ partis, gouvernements, appareils d'Etat ­ fonctionnent dans ces pays, mais plutôt d'y identifier, dans l'espace public et l'espace privé et aux plans individuel et collectif, les discours, les idées et les comportements, qui peuvent être interprétés comme des signes, des indicateurs de processus de sécularisation et de démocratisation et leur impact sur les institutions politiques et étatique

    How do supply chain management and information systems practices influence operational performance?:Evidence from emerging country SMEs

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    This study first provides a comparative analysis of the impact of supply chain management (SCM) and information systems (IS) practices on operational performance (OPER) of small- and medium-sized enterprises (SMEs) operating in two neighbouring emerging country markets of Turkey and Bulgaria. Then, we investigate moderating effects of both SCM–IS-linked enablers and inhibitors on the links between SCM and IS practices and OPER of SMEs. To this end, we first empirically identify the underlying dimensions of SCM and IS practices, and SCM–IS-related enabling and inhibiting factors. Second, a series of regression analyses are undertaken to estimate the impact of the study's constructs on OPER of SMEs. The results are discussed comparatively within the contexts of both Turkish and Bulgarian SMEs and beyond. The study makes a significant contribution to the extant literature through obtaining and analysing cross-national survey data of SCM and IS practices in emerging country markets

    Particle-based simulation and visualization of fluid flows through porous media

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    We propose a method of fluid simulation where boundary conditions are designed in such a way that fluid flow through porous media, pipes, and chokes can be realistically simulated. Such flows are known to be low Reynolds number incompressible flows and occur in many real life situations. To obtain a high quality fluid surface, we include a scalar value in isofunction. The scalar value indicates the relative position of each particle with respect to the fluid surface

    Practical and realistic animation of cloth

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    In this paper, we propose a system for the practical animation of cloth materials. A mass spring based cloth model is used. Explicit time integration methods are used to solve the equations of motion. We update the spring constants dynamically according to the net force acting on them. In this way, spring constants do not grow arbitrarily to introduce numerical instability and realistic cloth appearance without over elongation is obtained. © 2007 IEEE
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