Semi Infinite Research Articles

A Robust Adaptive Objective Power Allocation in Cognitive NOMA Networks.

Cognitive radio (CR) is a candidate for opportunistic spectrum implementation in wireless communications, allowing secondary users (SUs) to share the spectrum with primary users (PUs). In this paper, a robust adaptive target power allocation strategy for cognitive nonorthogonal multiple access (NOMA) networks is proposed, which involves the maximum transmission power of each SU and interference power threshold under PU constraints. By introducing the signal-to-interference-plus-noise ratio (SINR) adjustment factor, the strategy enables single-station communication to achieve energy efficiency (EE) or high throughput (HT), thus making the target function more flexible. In the same communication scenario, different cognitive users can choose different communication targets that meet their needs. Different QoS can be selected by the same cognitive user at different times. In the case of imperfect channel state information (CSI), semi-infinite (SI) constraints with bounded uncertainty sets are transformed into an optimization problem under the worst case, which is solved by the dual decomposition method. Simulation results show that this strategy has good adaptive selectivity and robustness.

Numerical Solutions for Chemically Reactive Non-Newtonian Nanofluid over a Semi Infinite Moving Flat Plate with Heat Generation

A hypothetical report was performed to contemplate the consistent two-dimensional flow of incompressible non-Newtonian nanofluids on a semi-infinite moving plate, considering viscous scattering of heat generation and third-request chemical responses. The methodology of Eyring Powell is utilized for the liquid. The solution is derived for the transformed equations by utilizingRunge-Kutta4thorder method in conjunction with shooting technique. The numerical convergence and precision of the outcomes are exhibited. The effects of the different parameters identified with this investigation are exhibited through graphs and tables separately. The outcomes demonstrate that there exists a significant improvement in the velocity of nanofluid along with the increase of both velocity and material parameters. Further, there is an improvement in the temperature of the nanofluid and decrement in the pace of heat move for the expanding enlarges of heat generation parameter. Furthermore, by increasing viscous dissipation parameter nanofluid temperature and Sherwood number are increased and Nusselt number decreased. At long last, the consequences of this investigation were contrasted and the outcomes gave in the writing.

Semi-Infinite Solid Solution Adjusted for Radial Systems Using Time-Dependent Participating Volume-to-Surface Ratio and Simplified Solutions for Finite Solids

Time-dependent participating volume-to-surface ratio, V(t)/A, is used to adjust the semi-infinite (SI) solid solutions to the radial systems. In cylinders and spheres, the present “radial” SI sold model extends the domain of the planar model from δ ≪ R to δ ≈ R (δ is transient penetration depth and R is radius). The corresponding increase in the time span is from 0 < Fo < 0.01 to 0 < Fo < 0.06). The erfc series solution for finite solids (FS), which converges rapidly at small values of time, is simplified, by truncating the first term of the solution. For cylinders and spheres, the resulting half-term approximations are far more precise than the planar SI solid solutions.

HEAT AND MASS TRANSFER ON MHD FLUID FLOW OVER A SEMI INFINITE FLAT PLATE WITH RADIATION ABSORPTION, HEAT SOURCE AND DIFFUSION THERMO EFFECT

HEAT AND MASS TRANSFER ON MHD FLUID FLOW OVER A SEMI INFINITE FLAT PLATE WITH RADIATION ABSORPTION, HEAT SOURCE AND DIFFUSION THERMO EFFECT

Generalized Beamforming Design for Cooperative MIMO Multirelay Networks with Infinite Constraints and Imperfect CSI

A generalized base station-relay-user equipment (BS-Relay-UE) beamforming design is investigated for a cooperative multiple-input multiple-output (MIMO) multirelay networks with imperfect channel state information (CSI). In order to minimize the worst-case mean square error (MSE) which is subject to a semi-infinite (SI) relay power constraints, a generalized optimal beamforming structure for the relay amplifying matrix is effectively proposed, and then the SI relay power constraints are converted into linear matrix inequalities (LMIs) version. In such conversion, the objective problem recasts as a decoupled biconvex semidefinite programming (SDP) one which can be efficiently solved by the proposed alternating algorithm. The system performance has been verified in terms of worst-case MSE using a set of qualitative analyses. The results show us that the proposed beamforming method outperforms the conventional schemes and can also effectively reduce the computational complexity when it is compared to the cutting-set schemes and also to the nonrobust ones.

Soret and Dufour Effects on MHD Free Convective Flow Past a Semi Infinite Vertical Permeable Moving Porous Plate with Heat and Mass Transfer

Soret and Dufour Effects on MHD Free Convective Flow Past a Semi Infinite Vertical Permeable Moving Porous Plate with Heat and Mass Transfer

Analysis of Heat and Mass Transfer on MHD flow with Ag, Al2O3 and Cu Water Nanofluids over a Semi Infinite Surface

Analysis of Heat and Mass Transfer on MHD flow with Ag, Al₂O₃ and Cu Water Nanofluids over a Semi Infinite Surface

Similarity Solution for Combined Free-Forced Convection Past a Vertical Porous Plate in a Porous Medium with a Convective Surface Boundary Condition

This paper studies the mathematical implications of the two dimensional viscous steady laminar combined free-forced convective flow of an incompressible fluid over a semi infinite fixed vertical porous plate embedded in a porous medium. It is assumed that the left surface of the plate is heated by convection from a hot fluid which is at a temperature higher than the temperature of the fluid on the right surface of the vertical plate. To achieve numerical consistency for the problem under consideration, the governing non linear partial differential equations are first transformed into a system of ordinary differential equations using a similarity variable and then solved numerically under conditions admitting similarity solutions. The effects of the physical parameters of both the incompressible fluid and the vertical plate on the dimensionless velocity and temperature profiles are studied and analysed and the results are depicted both graphically and in a tabular form. Finally, algebraic expressions and the numerical values are obtained for the local skin-friction coefficient and the local Nusselt number.

Soret Effect Due to Mixed Convection on Unsteady Magnetohydrodynamic Flow Past a Semi Infinite Vertical Permeable Moving Plate in Presence of Thermal Radiation, Heat Absorption and Homogenous Chemical Reaction

In this article we have investigated the Soret effect due to mixed convection on unsteady magneto hydrodynamic flow past a semi-infinite vertical permeable moving plate in presence of thermal radiation, heat absorption and homogenous chemical reaction, subjected to variable suction. The plate is assumed to be embedded in a uniform porous medium and moves with a constant velocity in the flow direction in the presence of a transverse magnetic field. The equations governing the flow are transformed into a system of nonlinear ordinary differential equations by using perturbation technique. Graphical results for the velocity distribution, temperature distribution and concentration distribution based on the numerical solutions are presented and discussed. We also discuss the effects of various parameters on the skin-friction coefficient and the rate of heat transfer in the form of Nusselt number and rate of mass transfer in the form of Sherwood number at the surface. Velocity distribution is observed to increase with an increase in Soret number and in the presence of permeability, where as it shows reverse effects in the case of heat absorption coefficient, magnetic parameter, radiation parameter and chemical reaction parameter.

Thermal Diffusion Effect on MHD Heat and Mass Transfer Flow past a Semi Infinite Moving Vertical Porous Plate with Heat Generation and Chemical Reaction

The objective of present work is to study the thermo diffusion effect on an unsteady simultaneous convective heat and mass transfer flow of an incompressible, electrically conducting, heat generating/absorbing fluid along a semi-infinite moving porous plate embedded in a porous medium with the presence of pressure gradient, thermal radiation field and chemical reaction. It is assumed that the permeable plate is embedded in a uniform porous medium and moves with a constant velocity in the flow direction in the presence of a transverse magnetic field. It is also assumed that the free stream consists of a mean velocity, temperature and concentration over which are super imposed an exponentially varying with time. The equations of continuity, momentum, energy and diffusion, which govern the flow field, are solved by using a regular perturbation method. The behavior of the velocity, temperature, concentration, Skin-friction, rate of heat transfer and rate of mass transfer has been discussed for variations in the physical parameters. An increase in both Pr and R results a decrease in thermal boundary layer thickness. However, concentration decreases as Kr, Sc increase but it increases with an increase in both So and δ.

Elastic Deformation on an Orthotropic Semi Infinite Plate with Straight Boundary Asymmetric with Respect to the Elastic Axes of the Material under Uniform Partial Loading

The solution of the problem of an orthotropic semi-infinite plate with straight boundary asymmetric with respect to the elastic of the material has been obtained under the assumption that a part of the boundary near the origin is uniformly stressed and the rest is stress-free. The use of Beltrami Cayley's conformal mapping has been made. In particular, the solution has been obtained for the plate with a concentrated force.

On a constructive approach to optimality conditions for convex SIP problems with polyhedral index sets

In the paper, we consider a problem of convex Semi-Infinite Programming with an infinite index set in the form of a convex polyhedron. In study of this problem, we apply the approach suggested in our recent paper [Kostyukova OI, Tchemisova TV. Sufficient optimality conditions for convex Semi Infinite Programming. Optim. Methods Softw. 2010;25:279–297], and based on the notions of immobile indices and their immobility orders. The main result of the paper consists in explicit optimality conditions that do not use constraint qualifications and have the form of criterion. The comparison of the new optimality conditions with other known results is provided.

Approximate Solution of Linear Boundary Value Problem Defined on Semi Infinite Interval

Approximate Solution of Linear Boundary Value Problem Defined on Semi Infinite Interval

Two Temperature Heat Flux of Semi Infinite Piezoelectric Ceramic Rod

The theory of two-temperature generalized thermoelasticity is used to solve the problem of heating a semi-infinite rod made of a piezoelectric ceramic material within the framework of generalized thermopiezoelasticity theory by supplying the rod a certain amount of heat uniformly distributed over a finite time period to the finite end of the rod. The Laplace transform formalism is used to solve the proposed model. Inverse Laplace transforms are computed numerically using a method based on Fourier expansion techniques. The physical parameters (i.e., conductive temperature, dynamical temperature, stress, strain, and displacement distributions) are investigated graphically.

Thermal Stress of Porous Semi Infinite Media Subjected to Gas Infiltration and Heat Transfer

Thermal Stress of Porous Semi Infinite Media Subjected to Gas Infiltration and Heat Transfer

半无限大生物组织中光子分布规律的研究

半无限大生物组织中光子分布规律的研究

半无限大生物组织中光子分布规律的研究

半无限大生物组织中光子分布规律的研究

Effects of Mixed Convection and Double Dispersion on Semi Infinite Vertical Plate in Presence of Radiation

Effects of Mixed Convection and Double Dispersion on Semi Infinite Vertical Plate in Presence of Radiation

Modeling of Urea Release from Briquettes Using Semi infinite and Shrinking Core Models

Briquetted urea is commonly used in wet agricultural soils since it has potential to reduce loss of urea occuring in the fields by various mechanisms. In the present study, commercially available uncoated urea briquettes were subjected to release in wet loam and wet silty clay soils, both maintained at 40% moisture, measured on dry basis. Adapted semi infinite model and developed shrinking core model predictions were compared with the experimentally determined concentration profiles and unreleased quantity of urea, respectively. Semi infinite model developed with the assumption of unchanging briquette size did not match well with experimental results. However, shrinking core model predicted the unreleased urea contents in briquettes reasonably well.

Position-dependent exact-exchange energy for slabs and semi-infinite jellium

The position-dependent exact-exchange energy per particle $\varepsilon_x(z)$ (defined as the interaction between a given electron at $z$ and its exact-exchange hole) at metal surfaces is investigated, by using either jellium slabs or the semi-infinite (SI) jellium model. For jellium slabs, we prove analytically and numerically that in the vacuum region far away from the surface $\varepsilon_{x}^{\text{Slab}}(z \to \infty) \to - e^{2}/2z$, {\it independent} of the bulk electron density, which is exactly half the corresponding exact-exchange potential $V_{x}(z \to \infty) \to - e^2/z$ [Phys. Rev. Lett. {\bf 97}, 026802 (2006)] of density-functional theory, as occurs in the case of finite systems. The fitting of $\varepsilon_{x}^{\text{Slab}}(z)$ to a physically motivated image-like expression is feasible, but the resulting location of the image plane shows strong finite-size oscillations every time a slab discrete energy level becomes occupied. For a semi-infinite jellium, the asymptotic behavior of $\varepsilon_{x}^{\text{SI}}(z)$ is somehow different. As in the case of jellium slabs $\varepsilon_{x}^{\text{SI}}(z \to \infty)$ has an image-like behavior of the form $\propto - e^2/z$, but now with a density-dependent coefficient that in general differs from the slab universal coefficient 1/2. Our numerical estimates for this coefficient agree with two previous analytical estimates for the same. For an arbitrary finite thickness of a jellium slab, we find that the asymptotic limits of $\varepsilon_{x}^{\text{Slab}}(z)$ and $\varepsilon_{x}^{\text{SI}}(z)$ only coincide in the low-density limit ($r_s \to \infty$), where the density-dependent coefficient of the semi-infinite jellium approaches the slab {\it universal} coefficient 1/2.