New bounds on RAKE structures for DS-CDMA over frequency-selective Rayleigh fading channels

An upper bound is derived for the probability of error in an asynchronous binary direct-sequence spread-spectrum multiple-access communications system operating over frequency selective Rayleigh fading channels. A coherent RAKE receiver with predetection selective diversity combining is considered. The performance of a multipath-combining receiver is determined for the case of multiple interfering transmitters. Furthermore, the performance of the system is determined in terms of parameters of the signature sequences. These parameters can be used as guides in selecting sequences for the system. The bounds agree with the exponential portion of a normal distribution in which the interfering interference components subtract from the signal amplitude. The results obtained are verified by simulation.Peer ReviewedPostprint (published version

Sobreprotección en la persona con lesión medular tras el alta, visión desde T.O.

[Resumen] El proceso de rehabilitación integral de un persona con lesión medular es prolongado en el tiempo y consta de varias fases como encamamiento, sedestación, rehabilitación activa o reintegración social. Es decir, no se limita simplemente a la estancia hospitalaria, la rehabilitación debe proseguir tras el alta en la Unidad y una de la formas más efectivas de conseguirlo es realizar las Actividades de la Vida Diaria de la manera más autónoma posible. En el presente proyecto se pretende demostrar la necesidad de una concienciación colectiva, destinada a las familias y entorno social más cercano de la persona adulta con lesión medular. Mostrando que no todas estas personas precisan los mismos cuidados, enseñarles la importancia de la independencia y sus repercusiones positivas sobre la salud, pero también remarcar las consecuencias negativas que puede provocar el hecho de sobreproteger a la persona, impidiéndole de esta forma ser independiente y pudiendo influir sobre su desempeño en ocupaciones futuras. Resumen metodología: El estudio será cuantitativo correlacional, ya que lo que buscamos es medir el grado de relación entre las variables (sobreprotección y nivel de independencia). Esta metodología permite extrapolar los resultados. Para llevarla a cabo se utilizarán una serie de cuestionarios y la base de datos SIMON.[Resumo] O proceso de rehabilitación integral dunha persoa con lesión medular é prolongada no tempo e está composto por varias fases desde o repouso , sentado , rehabilitación activa ou a reintegración social . É dicir , non se limita á permanencia hospitalaria , a rehabilitación debe continuar despois da alta na unidade e unha das formas máis eficaces para alcanzar este obxectivo é realizar as actividades da vida diaria de forma tan independente como sexa posible . Neste proxecto preténdese demostrar a necesidade dunha conciencia colectiva, destinada a familias e máis ao ambiente social próximo da persoa con lesión medular adulta . Mostrando que non todas estas persoas precisan destes coidados , ensinarlles a importancia da independencia e do seu impacto positivo sobre a saúde , pero tamén destacar as consecuencias negativas que pode producir o feito de sobreprotexer á persoa, impedindolle así ser independente e influíndo nas súas habilidades de desempeño. Resumo Metodoloxía : O estudo é cuantitativo correlacional , xa que buscamos medir o grao de relación entre as variables ( sobreproteción e nivel de independencia ) . Esta metodoloxía permite extrapolar os resultados . Para levala a cabo utilizaranse unha serie de cuestionarios e base de datos SIMON.[Abstract] The process of comprehensive rehabilitation of a person with spinal cord injury is prolonged in time and consists of several phases as bed rest , sitting, active rehabilitation or social reintegration. That is, it is not simply limited to the hospital stay , rehabilitation should continue after discharge in the unit and one of the most effective ways to achieve this is to perform the Activities of Daily Living as independently as possible. In this project it is to demonstrate the need for a collective awareness, aimed at families and closest to the adult spinal cord injury social environment. Showing that not all of these people need the same care, teach them the importance of independence and its positive impact on health, but also highlight the negative consequences that may result in the fact overprotect the person, preventing him thus be independent and can influence their performance skills in their future occupations . Summary Methodology : The study is quantitative correlational , as we seek to measure the degree of relationship between variables ( overprotection and level of independence ) . This methodology allows us to extrapolate the results . To carry out a series of questionnaires and data base will be used SIMON .Traballo fin de grao (UDC.FCS). Terapia ocupacional. Curso 2015/201

Ferroelectric materials for photovoltaics

En col·laboració amb la Universitat Autònoma de Barcelona (UAB), la Universitat de Barcelona (UB) i l’Institut de Ciències Fotòniques (ICFO)Ferroelectric photovoltaic has been intensively studied during the last years due to possible high efficient charge separation by presence of an internal electric field. Ferroelectric materials show permanent electrical polarization. Ideally, electric contacts would screen the polarization, but if screening is not perfect, it results in the generation of depolarization field. In this report, we study the photoelectric response of LuMnO3 that shows a small bandgap compared to archetypical ferroelectric materials and a sizeable internal polarization. We have studied its photoresponse dependence on polarization state

Mathematical analysis and numerical methods for pricing pension plans allowing early retirement

In this paper, we address the mathematical analysis and numerical solution of a model for pricing a defined benefit pension plan. More precisely, the benefits received by the member of the plan depend on the average salary and early retirement is allowed. Thus, the mathematical model is posed as an obstacle problem associated to a Kolmogorov equation in the time region where the salary is being averaged. Previously to the initial averaging date, a nonhomogeneous one factor Black-Scholes equation is posed. After stating the model, existence and regularity of solutions are studied. Moreover, appropriate numerical methods based on a Lagrange-Galerkin discretization and an augmented Lagrangian active set method are proposed. Finally, some numerical examples illustrate the performance of the numerical techniques and the properties of the solution and the free boundary.retirement plans, options pricing, Kolmogorov equations, complementarity problem, numerical methods, augmented Lagrangian formulation

Finite elements numerical solution of a coupled profile–velocity–temperature shallow ice sheet approximation model

AbstractThis work deals with the numerical solution of a complex mathematical model arising in theoretical glaciology. The global moving boundary problem governs thermomechanical processes jointly with ice sheet hydrodynamics. One major novelty is the inclusion of the ice velocity field computation in the framework of the shallow ice model so that it can be coupled with profile and temperature equations. Moreover, the proposed basal velocity and shear stress laws allow the integration of basal sliding effects in the global model. Both features were not taking into account in a previous paper (Math. Model. Methods Appl. Sci. 12 (2) (2002) 229) and provide more realistic convective terms and more complete Signorini boundary conditions for the thermal problem. In the proposed numerical algorithm, one- and two-dimensional piecewise linear Lagrange finite elements in space and a semi-implicit upwinding scheme in time are combined with duality and Newton's methods for nonlinearities. A simulation example involving real data issued from Antarctic shows the temperature, profile and velocity qualitative behaviour as well as the free boundaries and basal effects

Biblioteca Nacional de España: Música

Fac. de Ciencias de la DocumentaciónTRUEpu

Mathematical analysis of obstacle problems for pricing fixed-rate mortgages with prepayment and default options

[Abstract] In this paper, we address the mathematical analysis of a partial differential equation model for pricing fixed-rate mortgages with prepayment and default options, where the underlying stochastic factors are the house price and the interest rate. The mathematical model is posed in terms of a sequence of linked complementarity problems, one for each month of the loan life, associated with a uniformly parabolic operator. We study the existence of a strong solution to each one of the obstacle problems.This work has been partially funded by Spanish MINECO (Grant numbers MTM2013-47800-C2-1-P and MTM2016-76497-R) and Xunta de Galicia grant GRC2014/044, including FEDER funds.Xunta de Galicia; GRC2014/04

Pricing pension plans under jump–diffusion models for the salary

[Abstract] In this paper we consider the valuation of a defined benefit pension plan in the presence of jumps in the underlying salary and including the possibility of early retirement. We will consider that the salary follows a jump–diffusion model, thus giving rise to a partial integro-differential equation (PIDE). After posing the model, we propose the appropriate numerical methods to solve the PIDE problem. These methods mainly consists of Lagrange–Galerkin discretizations combined with augmented Lagrangian active set techniques and with the explicit treatment of the integral term. Finally, we compare the numerical results with those ones obtained with Monte Carlo techniques.This paper has been partially funded by MCINN (Project MTM2010-21135-C02-01 and MTM2013-47800-C2-1-P) and by Xunta de Galicia (Ayuda GRC2014/044, partially funded with FEDER funds).Xunta de Galicia; GRC2014/04

Pricing pension plans based on average salary without early retirement: partial differential equation modeling and numerical solution

[Abstract] In this paper, a partial differential equation model for the pricing of pension plans based on average salary is posed by using the dynamic hedging methodology. The existence and uniqueness of solutions for the resulting initial-value problem associated with a Kolmogorov equation is obtained. Moreover, a numerical method based on a Crank–Nicolson characteristics time discretization combined with finite elements to approximate the solution is proposed. Finally, some test examples illustrate the performance of the numerical methods as a tool for pricing these pension plans.This paper was partly funded by MCINN (Project MTM2010–21135–C02-01) and by Xunta de Galicia (Project INCITE09105339PR and Ayuda CN2011/004, cofinanced with FEDER funds).Xunta de Galicia; INCITE09105339PRXunta de Galicia; CN2011/00