Search results for "Linear"
showing 10 items of 7165 documents
Technical characteristics can make the difference in a surgical linear stapler. Or not?
2015
Background Anastomotic leak (AL) after gastrointestinal surgery is a severe complication associated with relevant short- and long-term sequelae. Most of the anastomosis are currently performed with a surgical stapler that is required to have appropriate characteristics to guarantee good performances. The aim of our study was to evaluate, in the laboratory, pressure resistance and tensile strength of anastomosis performed with different surgical linear staplers, available in the market. Materials and methods We have been studying three linear staplers, with diverse cartridges and staple heights, of three different companies, used for gastrointestinal anastomosis and gastric or intestinal clo…
3D SINGLETONS AND THEIR BOUNDARY 2D CONFORMAL FIELD THEORY
1999
This paper is a continuation of recent work of Flato and Frønsdal on singletons in 1+2 anti De Sitter universe and their link with 2D conformal field theories on the boundary. More specifically we show that in this framework we can construct a 3D-singleton model in the bulk, the limit of which on the boundary of De Sitter space is a Gupta–Bleuler triplet for two commuting copies of the Witt algebra. We also generalize this result to the case of WZNW models.
Schelling-Voter Model: An Application to Language Competition
2013
In this work we analyze the language competition problem by using an interacting agent-based model which interpolates the classical Schelling and Voter models. Briefly, an agent may change its place of residence or his language when he is surrounded by more individuals of the other kind than the ones he can tolerate. We analyze this dynamic process in terms of the free space to move in, the pressure to change the language, and the propensity to change location. We identify the different regimes and the relationship with the language competition problem. Fil: Caridi, Délida Inés. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Cálculo; Argentina. Consejo N…
Dealing with Product Similarity in Conjoint Simulations
2001
One of the reasons conjoint analysis has been so popular as a management decision tool has been the availability of a choice simulator. These simulators often arrive in the form of a software or spreadsheet program accompanying the output of a conjoint study. These simulators enable managers to perform ‘what if’ questions about their market—estimating market shares under various assumptions about competition and their own offerings. As examples, simulators can predict the market share of a new offering; they can estimate the direct and cross elasticity of price changes within a market, or they can form the logical guide to strategic simulations that anticipate short- and long-term competiti…
An Efficient Numerical Method for Time Domain Computational Electromagnetic Simulation
2018
In this paper an efficient numerical method in approximating the electric and magnetic fields is provided. The method is based on an implicit leapfrog arrangement in time and without mesh in space. Moreover, a projection scheme is introduced in order to improve the accuracy of the proposed approach and applied into the computational electromagnetic (CEM) framework. The PDEs governing the process are solved and some numerical results are reported to validate the numerical process.
groups acting on the line and the circle with at most N fixed points
2022
A classical theme in dynamical systems is that the first fundamental information comes from the understanding of periodic orbits. When studying group actions, this means that we want to understand the fixed points of elements of the group, and a natural question that emerges from that is: Which groups of homeomorphisms can act on a 1-manifold having all non-trivial elements with at most N fixed points? Our main objective in this work is to approach that question and understand what properties can such dynamical hypothesis induces to the group.For the case N=0, a classical result from O. Hölder implies that such group of homeomorphisms acting on the line is always semi-conjugate to a subgrou…
Intermittent and passivity based control strategies for a hyperchaotic system
2013
In this paper a four-dimensional hyperchaotic system with only one equilibrium is consid- ered and it is shown how the control and the synchronization of this system can be realized via two different control techniques. Firstly, we propose a periodically intermittent con- troller to stabilize the system states to the equilibrium and to achieve the projective syn- chronization of the system both in its periodic and hyperchaotic regime. Then, based on the stability properties of a passive system, we design a linear passive controller, which only requires the knowledge of the system output, to drive the system trajectories asymptoti- cally to the origin. Using the same passivity-based method, …
Examination of the least-squares method applied to the evaluation of physicochemical parameters with linearized equations
1989
Physicochemical parameters are frequently evaluated by the least-squares method after linearization of the equation which relates the experimental variables to the parameters of interest. When a given set of data is treated to evaluate (n+1) parameters. (n+2) nominally identical linearized equations are possible; each of these leads to different sets of values of the parameters which are also affected by different variances. These differences are also observed when statistical weights are used. Two methods for establishing which one of the (n+2) equations is best for fitting the data, i.e., simulation of experiments and propagation of errors, are discussed, compared and applied to a potenti…
Neural network approach to solving fuzzy nonlinear equations using Z-numbers
2020
In this article, the fuzzy property is described by means of the Z-number as the coefficients and variables of the fuzzy equations. This alteration for the fuzzy equation is appropriate for system modeling with Z-number parameters. In this article, the fuzzy equation with Z-number coefficients and variables is tended to be used as the models for the uncertain systems. The modeling issue related to the uncertain system is to obtain the Z-number coefficients and variables of the fuzzy equation. Nevertheless, it is extremely hard to get the Z-number coefficients of the fuzzy equations. In this article, in order to model the uncertain nonlinear systems, a novel structure of the multilayer neura…
A Non-linear Diffeomorphic Framework for Prostate Multimodal Registration
2011
International audience; This paper presents a novel method for non-rigid registration of prostate multimodal images based on a nonlinear framework. The parametric estimation of the non-linear diffeomorphism between the 2D fixed and moving images has its basis in solving a set of non-linear equations of thin-plate splines. The regularized bending energy of the thin-plate splines along with the localization error of established correspondences is jointly minimized with the fixed and transformed image difference; where, the transformed image is represented by the set of non-linear equations defined over the moving image. The traditional thin-plate splines with established correspondences may p…