A Nonlinear Adiabatic Theorem for Coherent States

We consider the propagation of wave packets for a one-dimensional nonlinear Schrodinger equation with a matrix-valued potential, in the semi-classical limit. For an initial coherent state polarized along some eigenvector, we prove that the nonlinear evolution preserves the separation of modes, in a scaling such that nonlinear effects are critical (the envelope equation is nonlinear). The proof relies on a fine geometric analysis of the role of spectral projectors, which is compatible with the treatment of nonlinearities. We also prove a nonlinear superposition principle for these adiabatic wave packets.Comment: 21 pages, no figur

C ion-implanted TiO2 thin film for photocatalytic applications

Third-generation TiO2 photocatalysts were prepared by implantation of C+ ions into 110 nm thick TiO2 films. An accurate structural investigation was performed by Rutherford backscattering spectrometry, secondary ion mass spectrometry, X-ray diffraction, Raman-luminescence spectroscopy, and UV/VIS optical characterization. The C doping locally modified the TiO2 pure films, lowering the band-gap energy from 3.3 eV to a value of 1.8 eV, making the material sensitive to visible light. The synthesized materials are photocatalytically active in the degradation of organic compounds in water under both UV and visible light irradiation, without the help of any additional thermal treatment. These results increase the understanding of the C-doped titanium dioxide, helpful for future environmental applications. (C) 2015 AIP Publishing LLC

Pravci trajnoga poboljšavanja CRM strategije

The concept of relationship marketing has led to a paradigm change in marketing. Over the last few decades, numerous studies have analyzed the impact of customer relationship management (CRM) programs on customer satisfaction and loyalty. Quite a few CRM programs have been found to have little or no impact. Having already published several articles and cases on the subject, in this paper we set out to answer the following question: assuming a company already has a reasonably successful CRM strategy in place, how can it continuously adapt and improve that strategy? Our recommendation is that such companies implement a continuous improvement process at four different but complementary levels: first, review and reinforce the company’s mission, culture and values; second, reconsider and, if necessary, redesign the CRM strategy; third, manage the various relationship-building activities more effectively; and lastly, review and, if necessary, improve the quality of material and human resources, program execution and process governance. A systematic review of these four levels or “paths” of improvement should help generate and maintain high quality relationships over time.Koncept marketinga odnosa doveo je do promjene marketinške paradigme. Tijekom posljednjih nekoliko desetljeća u brojnim je istraživanjima analiziran učinak programa upravljanja odnosima s potrošačima (CRM, od engl. Customer Relationship Managament) na njihovo zadovoljstvo i lojalnost. Pronađeno je svega nekoliko CRM programa s malim ili nikakvim utjecajem. S obzirom na to da smo već objavili nekoliko članaka i poslovnih slučajeva s ovom temom, ovim radom nastojimo odgovoriti na sljedeće pitanje: Ako se pretpostavlja da poduzeće već provodi uspješnu strategiju upravljanja odnosima s potrošačima (CRM), kako se ona može neprekidno prilagođavati i poboljšavati? Naša preporuka je da takva poduzeća uvedu kontinuirani proces poboljšanja CRM programa na četiri različite, ali nadopunjavajuće razine. Prva je osvrt na misiju, kulturu i vrijednosti poduzeća i njihovo ojačavanje. Promišljanje o strategiji odnosa s potrošačima i, ako je potrebno, njihovo redizajniranje predstavlja drugu razinu, dok je treća učinkovitije upravljanje različitim aktivnostima koje služe izgradnji odnosa između potrošača i poduzeća. Zadnju razinu predstavljaju provođenje ispitivanja i, ako je potrebno, poboljšavanje kvalitete korištenih materijalnih i ljudskih potencijala, izvedbe programa i upravljanja procesima. Sustavno ispitivanje ovih četiriju razina ili pravaca poboljšavanja trebalo bi tijekom vremena pomoći stvaranju i održavanju visoke kvalitete odnosa s potrošačima

Geometric optics and instability for semi-classical Schrodinger equations

We prove some instability phenomena for semi-classical (linear or) nonlinear Schrodinger equations. For some perturbations of the data, we show that for very small times, we can neglect the Laplacian, and the mechanism is the same as for the corresponding ordinary differential equation. Our approach allows smaller perturbations of the data, where the instability occurs for times such that the problem cannot be reduced to the study of an o.d.e.Comment: 22 pages. Corollary 1.7 adde

Off-Policy Deep Reinforcement Learning by Bootstrapping the Covariate Shift

In this paper we revisit the method of off-policy corrections for reinforcement learning (COP-TD) pioneered by Hallak et al. (2017). Under this method, online updates to the value function are reweighted to avoid divergence issues typical of off-policy learning. While Hallak et al.'s solution is appealing, it cannot easily be transferred to nonlinear function approximation. First, it requires a projection step onto the probability simplex; second, even though the operator describing the expected behavior of the off-policy learning algorithm is convergent, it is not known to be a contraction mapping, and hence, may be more unstable in practice. We address these two issues by introducing a discount factor into COP-TD. We analyze the behavior of discounted COP-TD and find it better behaved from a theoretical perspective. We also propose an alternative soft normalization penalty that can be minimized online and obviates the need for an explicit projection step. We complement our analysis with an empirical evaluation of the two techniques in an off-policy setting on the game Pong from the Atari domain where we find discounted COP-TD to be better behaved in practice than the soft normalization penalty. Finally, we perform a more extensive evaluation of discounted COP-TD in 5 games of the Atari domain, where we find performance gains for our approach.Comment: AAAI 201

The Persistence of Memory, or How the X-Ray Spectrum of SNR 0509-67.5 Reveals the Brightness of its Parent Type Ia Supernova

We examine the dynamics and X-ray spectrum of the young Type Ia supernova remnant 0509-67.5 in the context of the recent results obtained from the optical spectroscopy of its light echo. Our goal is to estimate the kinetic energy of the supernova explosion using Chandra and XMM-Newton observations of the supernova remnant, thus placing the birth event of 0509-67.5 in the sequence of dim to bright Type Ia supernovae. We base our analysis on a standard grid of one-dimensional delayed detonation explosion models, together with hydrodynamic and X-ray spectral calculations of the supernova remnant evolution. From the remnant dynamics and the properties of the O, Si, S, and Fe emission in its X-ray spectrum we conclude that 0509-67.5 was originated ~400 years ago by a bright, highly energetic Type Ia explosion similar to SN 1991T. Our best model has a kinetic energy of 1.4x10E51 erg and synthesizes 0.97 Msun of 56Ni. These results are in excellent agreement with the age estimate and spectroscopy from the light echo. We have thus established the first connection between a Type Ia supernova and its supernova remnant based on a detailed quantitative analysis of both objects.Comment: 10 pages, 9 figures, plus an exclusive astro-ph-only Appendix; ApJ in press, companion paper to Rest et al. 0

Cómo mejorar una estrategia relacional

La introducción del concepto de Marketing Relacional por Berry (1983) ha supuesto un cambio paradigma dentro del Marketing (Sheth y Parvatiyar 2002). En las últimas décadas se han realizado un gran número de investigaciones con el fin de analizar el impacto de los programas de marketing relacional en la satisfacción y fidelización de la base de clientes. Sin embargo, los resultados alcanzados por bastantes de estos programas han sido escasos o nulos. Tras haber publicado diversos artículos y casos sobre el tema, el presente trabajo aspira a responder a la siguiente pregunta: ¿cómo puede seguir avanzando y mejorando su estrategia de marketing relacional una empresa que ya la ha puesto en marcha con cierto nivel de éxito?. Nuestra propuesta es que estas empresas pongan en marcha un proceso de mejora continua a cuatro niveles distintos y complementarios: primero, revisar y profundizar la misión, cultura y valores de la empresa; segundo, replantear y en su caso rediseñar la estrategia relacional; tercero, mejorar la gestión de cada una de las distintas actividades relacionales; y finalmente, revisar y en su caso mejorar la calidad de los medios y del equipo humano, la ejecución, y el buen gobierno de todo el proceso. La revisión sistemática de los cuatro niveles o caminos de mejora debería dar como resultado la generación y sostenimiento en el tiempo de relaciones comerciales de alta calidad (relationship quality).Marketing relacional; fidelización cliente; calidad relación; confianza;