11,386 research outputs found

    Integrable Chern-Simons Gauge Field Theory in 2+1 Dimensions

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    The classical spin model in planar condensed media is represented as the U(1) Chern-Simons gauge field theory. When the vorticity of the continuous flow of the media coincides with the statistical magnetic field, which is necessary for the model's integrability, the theory admits zero curvature connection. This allows me to formulate the model in terms of gauge - invariant fields whose evolution is described by the Davey-Stewartson (DS) equations. The Self-dual Chern-Simons solitons described by the Liouville equation are subjected to corresponding integrable dynamics. As a by-product the 2+1-dimensional zero-curvature representation for the DS equation is obtained as well as the new reduction conditions related to the DS-I case. Some possible applications for the statistical transmutation in the anyon superfluid and TQFT are briefly discussed.Comment: 16 pages, plain Te

    Viscous flow simulations of internal store carriage and separation

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    The internal carriage of stores by the military aircraft is an option for possible reductions in the aerodynamic drag and the observability. Trade studies of this option require considering the aircraft and the stores together. In an effort to develop a computational fluid dynamic (CFD) code for such studies, an investigation was conducted from 1986 to 1990. The study was divided into five building-block steps. First, a full Navier-Stokes code was developed to simulate the unsteady, three-dimensional cavity flow. As the second step, this code was then used to simulate the flows past various missile configurations at angles of attack up to 44 deg. The effects of incidence as well as the turbulence on the leeside flows were computationally captured. The objective of this study has involved the interference flows of rather complex configurations with multiple, joint or disjoint, components of nonsimilar geometries. Hence, a hybrid domain decomposition (HDD) method was developed as the third step of the investigation. The strengths of the multiblock, zonal, and overlapped grids were judiciously combined and employed for the present problem. In the fourth step, the interference flow past a missile near a flat-plate wing was simulated using the HDD method. Finally, the fifth step involved the simulation of the internal store carriage and separation. Four different cases for two different configurations were simulated. The computational results of all five steps were successfully compared with the available wind tunnel test data. The unsteady aerodynamic forces on the separating store were computationally predicted. The CFD code developed for this project is called Viscous Internal Store Carriage Code (VISCC)

    Lying for the Greater Good: Bounded Rationality in a Team

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    The article is concerned with the interaction between fully and boundedly rational agents in situations where their interests are perfectly aligned. The cognitive limitations of the boundedly rational agent do not allow him to fully understand the market conditions and lead him to take non-optimal decisions in some situations. Using categorization to model bounded rationality, we show that the fully rational agent can manipulate information to help decreasing the expected loss caused by the boundedly rational agent. Assuming different types for the boundedly rational agent, who differ only in the categories used, we show that the fully rational agent may learn the type of the boundedly rational agent along their interaction. Using this additional information, the outcome can be improved and the amount of manipulated information can be decreased. Furthermore, as the length of the interaction gets longer the probability that the fully rational agent learns the type of the boundedly rational agent increases.Bounded rationality; categorization; learning.

    Does Education Pay off in Turkey? An Ordered Logit Approach

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    Abstract: This paper investigates the effect of education on individual income in Turkey. To this end, Mincerian (1974) earning equation is estimated in which income as a function of education, age, square of age and sex. Since all of the variables are in the form discrete choices, an ordered logit model is employed. This model lets to calculate probabilities of achieving higher income given education levels that are not provided by the earlier studies of Tansel (1994), Dayıoglu and Kasnakoglu (1997) and Ozcan et al.. (2003). The empirical findings show that as education level increases, the probability of achieving higher income raises notably. The finding of highest return for university education for both sexes supports the view; education should be considered as an investment and individuals should bear the cost of it to some extent.Keywords: Education, Income, ordered logit

    Navier-Stokes calculations of transonic flows past cavities

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    A computational investigation of subsonic and transonic flows past three dimensional deep and transitional cavities is presented. Computational simulations of these self induced oscillatory flows were generated through time accurate solutions of the Reynolds averaged full Navier-Stokes equations, using the explicit MacCormack scheme. The Reynolds stresses were included through the Baldwin-Lomax algebraic turbulence model with certain modifications. Two cases were computed to demonstrate the capability of the numerical scheme in modeling the complex three dimensional flow features inside a cavity. The results from an experimental investigation were used not only to benchmark the computations, but also to widen the database used for the discussions and conclusions. The computational results include instantaneous and time averaged flow properties everywhere in the computational zone. Time series analyses were performed for the instantaneous pressure values on the cavity floor. The features of deep and transitional cavity flows, and the effects of the sidewall on the cavity flow flowfield are illustrated through computational graphics
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