An athletic approach to studying perception-action integration: Does sport-specific training, and the impact of injury, influence how individuals visually guide navigation?

The objective of this thesis was to investigate perception-action integration capabilities of individuals during a choice navigation task. This task assessed navigation strategies in open space while individuals avoided colliding with two vertical obstacles that created a body-scaled, horizontal gap, at three varying obstacle distances from the starting location (3m, 5m, 7m). The two studies completed in this thesis employed the same paradigm to assess the hypothesized group differences. Gaze behaviours and kinematics of navigation strategies were compared between: 1) athletes specifically trained in navigating in open space versus non-athletes; and 2) athletes with post-concussion syndrome (PCS) versus non-concussed, specifically trained athletes. Specifically trained athletes have been identified as demonstrating more successful perception-action integration in discrete motor tasks related to their sport (Mann et al., 2007; Vickers, 2007). However, whether these abilities translate to the continuous motor task of obstacle avoidance in open space was unknown. The purpose of Study 1 was to identify the influence of sport-specific training on navigating in open space (i.e. navigational strategies of large field sport athletes) compared to age-matched, non-athletes. It was hypothesized that specifically-trained athletes would demonstrate fewer, longer fixations, suggesting a more successful perception-action integration strategy (as defined by Mann et al., 2007), and would employ more sport-specific navigation strategies than non-athletes by maintaining their straight trajectory toward the goal (Fajen & Warren, 2003). Athletes were found to make fewer, longer fixations than non-athletes. However, no differences were observed between navigation strategies of the two groups, nor were any kinematic measures found to differ between groups. It can be concluded that athletes and non-athletes differentially obtain visual information to perform the same actions, suggesting that athletes and non-athletes differentially perform perception-action integration when navigating in open space. Future studies are required to identify sport-specific nuances of navigation (moving obstacles, running) to better identify athletic-related navigation strategies. Although athletic training can enhance perception-action integration strategies, sport-related injuries can hinder this process. Following a concussion, individuals experience deficits of perception-action integration that persist well beyond 30 days of recovery, post-concussion (Baker and Cinelli, 2014; Slobounov et al., 2006). These perception-action integration deficits may also exist in individual with postconcussion syndrome (PCS). The purpose of the Study 2 was to identify whether perception-action integration deficits persist with the persistent physical symptoms of concussion characteristic of PCS. The current study revealed that athletes with PCS did not differ from non-concussed athletes on any measure of visual fixation strategy, nor were they found to differ on any kinematic measure assessed. These findings suggest that in the context of the current paradigm, athletes with PCS have no perception-action integration deficit. In that, athletes with PCS may have adapted perception-action integration strategies to navigate with equal efficiency as a specifically-trained group of athletes or that the paradigm was not sensitive enough to identify these differences. Such findings suggest that more research is required to assess what, if any, perception-action integration deficits persist with persisting physical symptoms of PCS to better benefit rehabilitative procedures and outcomes for these individuals. Together, these studies add to what was previously known about perception-action integration, as it relates to navigation. Both studies assessed perception-action integration in unique populations that add to understanding of behavioural dynamics in the sport setting. Study 1 builds on a line of research assessing affordance theory and behavioural dynamics in sport (Fajen, Riley, & Turvey, 2008). The findings of this study suggest that although navigation strategies did not differ between specifically trained athletes and non-athletes, visual search strategies employed in task did. Such findings add to the understanding that sport-specific training influences perception-action integration, through our understanding of how athletes obtain visual information to perform actions. This thesis did not identify perception-action integration deficits in athletes with PCS. These findings suggest that the individuals in the present study likely adapted to their injury as they demonstrated equal ability in gaze and navigation strategies to specifically-trained athletes. As such, further research is required to assess the cognitive, motor, and sensory-motor deficits that may persist with the persisting physical symptoms of PCS. As individuals with PCS do not demonstrate similar visuomotor integration deficits as individuals with acute concussions (Baker & Cinelli, 2014), such individuals must be assessed and researched as a separate population

Aspectos ideológicos de los discursos sobre drogas.

Existen otras maneras de explicar los consumos de drogas, diferentes a la ideología hegemónica representada por -y en- los discursos oficiales sobre drogas. Revisaremos algunos aspectos ideológicos en torno a las drogas así como otros postulados teóricos menos convencionales acerca del uso de drogas: Por una parte, encontramos autores que narran la historia de los consumos de drogas (ilícitas) como una cuestión de clase social. Por otro lado, encontramos el enfoque marxista, para el cual el consumo de drogas favorece el dominio de la ciudadanía [descerebrada] por los órganos de poder.There are other ways of explaining drug consumption, apart from the hegemonic ideology represented by the official discourse on drugs. In this text we will review some ideological aspects on drugs and other less conventional theoretical assumptions about drug use: On one hand, some authors narrate illicit drug use as a matter of social class. On the other hand, we find the Marxist approach, in which drug consumption helps the organs of power to control the [mindless] people

IPv6 Network Mobility

Network Authentication, Authorization, and Accounting has been used since before the days of the Internet as we know it today. Authentication asks the question, “Who or what are you?” Authorization asks, “What are you allowed to do?” And fi nally, accounting wants to know, “What did you do?” These fundamental security building blocks are being used in expanded ways today. The fi rst part of this two-part series focused on the overall concepts of AAA, the elements involved in AAA communications, and highlevel approaches to achieving specifi c AAA goals. It was published in IPJ Volume 10, No. 1[0]. This second part of the series discusses the protocols involved, specifi c applications of AAA, and considerations for the future of AAA

Scalable QoS-aware Mobility for Future Mobile Operators

Telecom operators and Internet service providers are heading for a new shift in communications paradigms. The forthcoming convergence of cellular and wireless data networks is often manifested in an “all IP approach” in which all communications are based on an end-to-end IP protocol framework. The approach to network design becomes user and service-centered, so that continuous reachability of mobile users and sustained communication capabilities are default requirements for a prospective architecture. In this article, we describe a network architecture which is able to provide seamless communication mobility, triggered either by the user or by the network, across multiple technologies. The architecture allows for media independent handovers and supports optimized mobility and resource management functions. The main focus of the article is on major technical highlights of mobility and quality-of-service (QoS) management subsystems for converged networks.Publicad

A polynomial Jacobi-Davidson solver with support for non-monomial bases and deflation

[EN] Large-scale polynomial eigenvalue problems can be solved by Krylov methods operating on an equivalent linear eigenproblem (linearization) of size d center dot n where d is the polynomial degree and n is the problem size, or by projection methods that keep the computation in the n-dimensional space. Jacobi-Davidson belongs to the latter class of methods, and, since it is a preconditioned eigensolver, it may be competitive in cases where explicitly computing a matrix factorization is exceedingly expensive. However, a fully fledged implementation of polynomial Jacobi-Davidson has to consider several issues, including deflation to compute more than one eigenpair, use of non-monomial bases for the case of large degree polynomials, and handling of complex eigenvalues when computing in real arithmetic. We discuss these aspects and present computational results of a parallel implementation in the SLEPc library.This work was supported by Agencia Estatal de Investigación (AEI) under Grant TIN2016-75985-P, which includes European Commission ERDF funds.Campos, C.; Jose E. Roman (2020). A polynomial Jacobi-Davidson solver with support for non-monomial bases and deflation. BIT Numerical Mathematics. 60(2):295-318. https://doi.org/10.1007/s10543-019-00778-zS295318602Bai, Z., Su, Y.: SOAR: a second-order Arnoldi method for the solution of the quadratic eigenvalue problem. SIAM J. Matrix Anal. Appl. 26(3), 640–659 (2005)Balay, S., Abhyankar, S., Adams, M., Brown, J., Brune, P., Buschelman, K., Dalcin, L., Eijkhout, V., Gropp, W., Karpeyev, D., Kaushik, D., Knepley, M., May, D., McInnes, L.C., Mills, R., Munson, T., Rupp, K., Sanan, P., Smith, B., Zampini, S., Zhang, H., Zhang, H.: PETSc users manual. Technical report ANL-95/11—revision 3.10, Argonne National Laboratory (2018)Betcke, T., Kressner, D.: Perturbation, extraction and refinement of invariant pairs for matrix polynomials. Linear Algebra Appl. 435(3), 514–536 (2011)Betcke, T., Voss, H.: A Jacobi–Davidson-type projection method for nonlinear eigenvalue problems. Future Gen. Comput. Syst. 20(3), 363–372 (2004)Betcke, T., Higham, N.J., Mehrmann, V., Schröder, C., Tisseur, F.: NLEVP: a collection of nonlinear eigenvalue problems. ACM Trans. Math. Softw. 39(2), 7:1–7:28 (2013)Campos, C., Roman, J.E.: Parallel Krylov solvers for the polynomial eigenvalue problem in SLEPc. SIAM J. Sci. Comput. 38(5), S385–S411 (2016)Effenberger, C.: Robust successive computation of eigenpairs for nonlinear eigenvalue problems. SIAM J. Matrix Anal. Appl. 34(3), 1231–1256 (2013)Effenberger, C., Kressner, D.: Chebyshev interpolation for nonlinear eigenvalue problems. BIT 52(4), 933–951 (2012)Fokkema, D.R., Sleijpen, G.L.G., van der Vorst, H.A.: Jacobi–Davidson style QR and QZ algorithms for the reduction of matrix pencils. SIAM J. Sci. Comput. 20(1), 94–125 (1998)Guo, J.S., Lin, W.W., Wang, C.S.: Numerical solutions for large sparse quadratic eigenvalue problems. Linear Algebra Appl. 225, 57–89 (1995)Hernandez, V., Roman, J.E., Vidal, V.: SLEPc: a scalable and flexible toolkit for the solution of eigenvalue problems. ACM Trans. Math. Softw. 31(3), 351–362 (2005)Higham, N.J., Al-Mohy, A.H.: Computing matrix functions. Acta Numer. 19, 159–208 (2010)Higham, N.J., Mackey, D.S., Tisseur, F.: The conditioning of linearizations of matrix polynomials. SIAM J. Matrix Anal. Appl. 28(4), 1005–1028 (2006)Hochbruck, M., Lochel, D.: A multilevel Jacobi–Davidson method for polynomial PDE eigenvalue problems arising in plasma physics. SIAM J. Sci. Comput. 32(6), 3151–3169 (2010)Hochstenbach, M.E., Sleijpen, G.L.G.: Harmonic and refined Rayleigh–Ritz for the polynomial eigenvalue problem. Numer. Linear Algebra Appl. 15(1), 35–54 (2008)Huang, T.M., Hwang, F.N., Lai, S.H., Wang, W., Wei, Z.H.: A parallel polynomial Jacobi–Davidson approach for dissipative acoustic eigenvalue problems. Comput. Fluids 45(1), 207–214 (2011)Hwang, F.N., Wei, Z.H., Huang, T.M., Wang, W.: A parallel additive Schwarz preconditioned Jacobi–Davidson algorithm for polynomial eigenvalue problems in quantum dot simulation. J.Comput. Phys. 229(8), 2932–2947 (2010)Kressner, D.: A block Newton method for nonlinear eigenvalue problems. Numer. Math. 114, 355–372 (2009)Kressner, D., Roman, J.E.: Memory-efficient Arnoldi algorithms for linearizations of matrix polynomials in Chebyshev basis. Numer. Linear Algebra Appl. 21(4), 569–588 (2014)Lancaster, P.: Linearization of regular matrix polynomials. Electron. J. Linear Algebra 17, 21–27 (2008)Matsuo, Y., Guo, H., Arbenz, P.: Experiments on a parallel nonlinear Jacobi–Davidson algorithm. Procedia Comput. Sci. 29, 565–575 (2014)Meerbergen, K.: Locking and restarting quadratic eigenvalue solvers. SIAM J. Sci. Comput. 22(5), 1814–1839 (2001)Roman, J.E., Campos, C., Romero, E., Tomas, A.: SLEPc users manual. Technical report DSIC-II/24/02—Revision 3.10, D. Sistemes Informàtics i Computació, Universitat Politècnica de València (2018)Romero, E., Roman, J.E.: A parallel implementation of Davidson methods for large-scale eigenvalue problems in SLEPc. ACM Trans. Math. Softw. 40(2), 13:1–13:29 (2014)Rommes, J., Martins, N.: Computing transfer function dominant poles of large-scale second-order dynamical systems. SIAM J. Sci. Comput. 30(4), 2137–2157 (2008)Saad, Y.: Iterative Methods for Sparse Linear Systems, 2nd edn. SIAM Publications, Philadelphia (2003)Sensiau, C., Nicoud, F., van Gijzen, M., van Leeuwen, J.W.: A comparison of solvers for quadratic eigenvalue problems from combustion. Int. J. Numer. Methods Fluids 56(8), 1481–1488 (2008)Sleijpen, G.L.G., van der Vorst, H.A.: A Jacobi–Davidson iteration method for linear eigenvalue problems. SIAM J. Matrix Anal. Appl. 17(2), 401–425 (1996)Sleijpen, G.L.G., Booten, A.G.L., Fokkema, D.R., van der Vorst, H.A.: Jacobi–Davidson type methods for generalized eigenproblems and polynomial eigenproblems. BIT 36(3), 595–633 (1996)Sleijpen, G.L.G., van der Vorst, H.A., Meijerink, E.: Efficient expansion of subspaces in the Jacobi–Davidson method for standard and generalized eigenproblems. Electron. Trans. Numer. Anal. 7, 75–89 (1998)Tisseur, F., Meerbergen, K.: The quadratic eigenvalue problem. SIAM Rev. 43(2), 235–286 (2001)van Gijzen, M.B., Raeven, F.: The parallel computation of the smallest eigenpair of an acoustic problem with damping. Int. J. Numer. Methods Eng. 45(6), 765–777 (1999)van Noorden, T., Rommes, J.: Computing a partial generalized real Schur form using the Jacobi–Davidson method. Numer. Linear Algebra Appl. 14(3), 197–215 (2007)Voss, H.: A Jacobi–Davidson method for nonlinear and nonsymmetric eigenproblems. Comput. Struct. 85(17–18), 1284–1292 (2007

NEP: A Module for the Parallel Solution of Nonlinear Eigenvalue Problems in SLEPc

[EN] SLEPc is a parallel library for the solution of various types of large-scale eigenvalue problems. Over the past few years, we have been developing a module within SLEPc, called NEP, that is intended for solving nonlinear eigenvalue problems. These problems can be defined by means of a matrix-valued function that depends nonlinearly on a single scalar parameter. We do not consider the particular case of polynomial eigenvalue problems (which are implemented in a different module in SLEPc) and focus here on rational eigenvalue problems and other general nonlinear eigenproblems involving square roots or any other nonlinear function. The article discusses how the NEP module has been designed to fit the needs of applications and provides a description of the available solvers, including some implementation details such as parallelization. Several test problems coming from real applications are used to evaluate the performance and reliability of the solvers.This work was partially funded by the Spanish Agencia Estatal de Investigacion AEI http://ciencia.gob.es under grants TIN2016-75985-P AEI and PID2019-107379RB-I00 AEI (including European Commission FEDER funds).Campos, C.; Roman, JE. (2021). NEP: A Module for the Parallel Solution of Nonlinear Eigenvalue Problems in SLEPc. ACM Transactions on Mathematical Software. 47(3):1-29. https://doi.org/10.1145/3447544S12947

Finanzas : Propuesta de la administración de inventario de la empresa comercializadora La Compañia,S.A.del periodo enero a noviembre 2017

En el presente trabajo se abordó conceptos y la importancia de la administración de inventario dentro de la empresa comercializadora “La compañía S, A” para el periodo enero a noviembre 2017 al realizar este trabajo obtuvimos información a través de libros y recursos de internet se quiso obtener y profundizar el tema ya que es muy amplio y para mayor comprensión es necesario conocer a fondo todos los conceptos aplicados. Se utilizó diferente metodología de investigación mediante visitas bibliográficas de libros y páginas web se logró obtener información confiable y segura tanto de la empresa en estudio y temas que relativamente se asocian a la administración de inventario, así mismo se realizó un caso práctico con información real de la empresa comercializadora “La Compañía S, A”. El caso práctico se realizó atreves del método de control de inventario ABC con este sistema se deduce que lo más conveniente que los materiales que mantienen un mayor volumen en el inventario sean los que menor costo representen del mismo

Los moriscos de Castellón (1525-1609). Del bautismo forzoso a la expulsión

Evolución del grupo de los antiguos mudéjares de Castellón convertidos en 1525 en cristianos nuevos o moriscos hasta su expulsión en 1609. (A