Optimal estimation of two-qubit pure-state entanglement

We present optimal measuring strategies for the estimation of the entanglement of unknown two-qubit pure states and of the degree of mixing of unknown single-qubit mixed states, of which N identical copies are available. The most general measuring strategies are considered in both situations, to conclude in the first case that a local, although collective, measurement suffices to estimate entanglement, a non-local property, optimally.Comment: REVTEX, 9 pages, 1 figur

Sistema de control interno. Compañía de Vida, Bancaseguros

Màster de Direcció d'Entitats Asseguradores i Financeres, Universitat de Barcelona, Facultat d'Economia i Empresa, Curs: 2006-2007, Tutor: Antoni VidiellaLas entidades aseguradoras, debido a las modificaciones normativas, deberán establecer unas directrices escritas sobre su sistema de control interno, basado en la gestión y control de riesgos. Además deberán elaborar anualmente un informe sobre la efectividad de los procedimientos de control interno. Este trabajo trata de crear una guía que ayude a las entidades de seguros a implementar un sistema de control interno, que permita la identificación de los riesgos de la entidad y sea de apoyo para la realización del informe anual. La estructura de la tesis comienza con una ilustración de los cambios legislativos, luego se detallan una serie de principios imprescindibles para un sistema de control interno y se definen los riesgos de una compañía de vida, cómo cuantificarlos según el proyecto de Solvencia II y las medidas que se pueden adoptar para controlarlos

Electron-beam deposited boron coatings for the extreme ultraviolet

Boron films deposited by evaporation with an electron-beam were found to have a relatively high reflectance in the extreme ultraviolet with values similar to those of ion-beam-sputtered (IBS) SiC and IBS B4C . The largest reflectance was measured for an 11¿nm thick boron film. Some reflectance degradation was observed for boron films stored in a desiccator. Reflectance degradation varied from sample to sample and was found to be either similar to that of IBS SiC and IBS B4C or larger. © 2008 Optical Society of AmericaThis work was supported by the National Programme for Space Research, Subdirección General de Proyectos de Investigación, Ministerio de Ciencia y Tecnología, project number ESP2005-02650. M. Fernández-Perea is thankful to Consejo Superior de Investigaciones Científicas (Spain) for funding under the Programa I3P (Ref. I3P-BPD2004) partially supported by the European Social Fund. We acknowledge the technical assistance of José M. Sánchez-Orejuela. M. Vidal-Dasilva is thankful to Ministerio de Educación y Ciencia for funding under the FPI BES-2006- 14047 fellowship.Peer Reviewe

Parallel Two-Stage Least Squares algorithms for Simultaneous Equations Models on GPU

Today it is usual to have computational systems formed by a multicore together with one or more GPUs. These systems are heterogeneous, due to the di erent types of memory in the GPUs and to the di erent speeds of computation of the cores in the CPU and the GPU. To accelerate the solution of complex problems it is necessary to combine the two basic components (CPU and GPU) in the heterogeneous system. This paper analyzes the use of a multicore+multiGPU system for solving Simultaneous Equations Models by the Two-Stage Least Squares method with QR decomposition. The combination of CPU and GPU allows us to reduce the execution time in the solution of large SEM.Ramiro Sánchez, C.; López-Espín, JJ.; Giménez, D.; Vidal, AM. (2012). Parallel Two-Stage Least Squares algorithms for Simultaneous Equations Models on GPU. http://hdl.handle.net/10251/1496

Parallel SUMIS Soft Detector for Large MIMO Systems on Multicore and GPU

[EN] The number of transmit and receiver antennas is an important factor that affects the performance and complexity of a MIMO system. A MIMO system with very large number of antennas is a promising candidate technology for next generations of wireless systems. However, the vast majority of the methods proposed for conventional MIMO system are not suitable for large dimensions. In this context, the use of high-performance computing systems, such us multicore CPUs and graphics processing units has become attractive for efficient implementation of parallel signal processing algorithms with high computational requirements. In the present work, two practical parallel approaches of the Subspace Marginalization with Interference Suppression detector for large MIMO systems have been proposed. Both approaches have been evaluated and compared in terms of performance and complexity with other detectors for different system parameters.This work has been partially supported by the Spanish MINECO Grant RACHEL TEC2013-47141-C4-4-R, the PROMETEO FASE II 2014/003 Project and FPU AP-2012/71274Ramiro Sánchez, C.; Simarro, MA.; Gonzalez, A.; Vidal Maciá, AM. (2019). Parallel SUMIS Soft Detector for Large MIMO Systems on Multicore and GPU. The Journal of Supercomputing. 75(3):1256-1267. https://doi.org/10.1007/s11227-018-2403-9S12561267753Rusek F, Persson D, Lau BK, Larsson EG, Marzetta TL, Edfors O, Tufvesson F (2013) Scaling up MIMO: opportunities and challenges with very large arrays. IEEE Signal Proc Mag 30(1):40–60Studer C, Burg A, Bölcskei H (2008) Soft-output sphere decoding: algorithms and VLSI implementation. IEEE J Sel Areas Commun 26(2):290–300Wang R, Giannakis GB (2004) Approaching MIMO channel capacity with reduced-complexity soft sphere decoding. In: Wireless Communications and Networking Conference, 2004. WCNC. 2004 IEEE vol 3, pp 1620–1625Persson D, Larsson EG (2011) Partial marginalization soft MIMO detection with higher order constellations. IEEE Trans Signal Procces 59(1):453–458Cîrkić M, Larsson EG (2014) SUMIS: near-optimal soft-in soft-out MIMO detection with low and fixed complexity. IEEE Trans Signal Process 62(12):3084–3097Alberto Gonzalez C, Ramiro, M, Ángeles Simarro, Antonio M Vidal (2017) Parallel SUMIS soft detector for MIMO systems on multicore. In: Proceedings of the 17th International Conference on Computational and Mathematical Methods in Science and Engineering, pp 1729–1736Hochwald BM, ten Brink S (2003) Achieving near-capacity on a multiple-antenna channel. IEEE Trans Commun 51:389–399Kaipeng L, Bei Y, Michael W, Joseph RC, Christoph S (2015) Accelerating massive MIMO uplink detection on GPU for SDR systems. In: 2015 IEEE dallas circuits and systems conference (DCAS), pp 1–4Di W, Eilert J, Liu D (2011) Implementation of a high-speed MIMO soft-output symbol detector for software defined radio. J Signal Process Syst 63(1):27–37Anderson E, Bai Z, Bischof C, Blackford LS, Demmel J, Dongarra J, Du Croz J, Greenbaum A, Hammarling S, McKenney A, Sorensen D (1999) LAPACK users’ guide. SIAM, LondonIntel MKL Reference Manual (2015) https://software.intel.com/en-us/articles/mkl-reference-manualcuBLAS Documentation (2015) http://docs.nvidia.com/cuda/cublasDagum L, Enon R (1998) OpenMP: an industry standard API for shared-memory programming. IEEE Comput Sci Eng 5(1):46–55CUDA Toolkit Documentation, Version 7.5 (2015) https://developer.nvidia.com/cuda-toolkitRoger S, Ramiro C, Gonzalez A, Almenar V, Vidal AM (2012) Fully parallel GPU implementation of a fixed-complexity soft-output MIMO detector. IEEE Trans Veh Technol 61(8):3796–3800Senst M, Ascheid G, Lüders H (2010) Performance evaluation of the markov chain monte carlo MIMO detector based on mutual information. 2010 IEEE International Conference on Communications (ICC), pp 1–

High performance lattice reduction on heterogeneous computing platform

The final publication is available at Springer via http://dx.doi.org/10.1007/s11227-014-1201-2The lattice reduction (LR) technique has become very important in many engineering fields. However, its high complexity makes difficult its use in real-time applications, especially in applications that deal with large matrices. As a solution, the modified block LLL (MB-LLL) algorithm was introduced, where several levels of parallelism were exploited: (a) fine-grained parallelism was achieved through the cost-reduced all-swap LLL (CR-AS-LLL) algorithm introduced together with the MB-LLL by Jzsa et al. (Proceedings of the tenth international symposium on wireless communication systems, 2013) and (b) coarse-grained parallelism was achieved by applying the block-reduction concept presented by Wetzel (Algorithmic number theory. Springer, New York, pp 323-337, 1998). In this paper, we present the cost-reduced MB-LLL (CR-MB-LLL) algorithm, which allows to significantly reduce the computational complexity of the MB-LLL by allowing the relaxation of the first LLL condition while executing the LR of submatrices, resulting in the delay of the Gram-Schmidt coefficients update and by using less costly procedures during the boundary checks. The effects of complexity reduction and implementation details are analyzed and discussed for several architectures. A mapping of the CR-MB-LLL on a heterogeneous platform is proposed and it is compared with implementations running on a dynamic parallelism enabled GPU and a multi-core CPU. The mapping on the architecture proposed allows a dynamic scheduling of kernels where the overhead introduced is hidden by the use of several CUDA streams. Results show that the execution time of the CR-MB-LLL algorithm on the heterogeneous platform outperforms the multi-core CPU and it is more efficient than the CR-AS-LLL algorithm in case of large matrices.Financial support for this study was provided by grants TAMOP-4.2.1./B-11/2/KMR-2011-0002, TAMOP-4.2.2/B-10/1-2010-0014 from the Pazmany Peter Catholic University, European Union ERDF, Spanish Government through TEC2012-38142-C04-01 project and Generalitat Valenciana through PROMETEO/2009/013 project.Jozsa, CM.; Domene Oltra, F.; Vidal Maciá, AM.; Piñero Sipán, MG.; González Salvador, A. (2014). High performance lattice reduction on heterogeneous computing platform. Journal of Supercomputing. 70(2):772-785. https://doi.org/10.1007/s11227-014-1201-2S772785702Józsa CM, Domene F, Piñero G, González A, Vidal AM (2013) Efficient GPU implementation of lattice-reduction-aided multiuser precoding. In: Proceedings of the tenth international symposium on wireless communication systems (ISWCS 2013)Wetzel S (1998) An efficient parallel block-reduction algorithm. In: Buhler JP (ed) Algorithmic number theory. Lecture notes in computer science, vol 1423. Springer, Berlin, Heidelberg, pp 323–337Wubben D, Seethaler D, Jaldén J, Matz G (2011) Lattice reduction. Signal Process Mag IEEE 28(3):70–91Lenstra AK, Lenstra HW, Lovász L (1982) Factoring polynomials with rational coefficients. Math Ann 261(4):515–534Bremner MR (2012) Lattice basis reduction: an introduction to the LLL algorithm and its applications. CRC Press, USAWu D, Eilert J, Liu D (2008) A programmable lattice-reduction aided detector for MIMO-OFDMA. In: 4th IEEE international conference on circuits and systems for communications (ICCSC 2008), pp 293–297Barbero LG, Milliner DL, Ratnarajah T, Barry JR, Cowan C (2009) Rapid prototyping of Clarkson’s lattice reduction for MIMO detection. In: IEEE international conference on communications (ICC’09), pp 1–5Gestner B, Zhang W, Ma X, Anderson D (2011) Lattice reduction for MIMO detection: from theoretical analysis to hardware realization. IEEE Trans Circ Syst I Regul Pap 58(4):813–826Shabany M, Youssef A, Gulak G (2013) High-throughput 0.13- \upmu μ m CMOS lattice reduction core supporting 880 Mb/s detection. IEEE Trans Very Large Scale Integr (VLSI) Syst 21(5):848–861Luo Y, Qiao S (2011) A parallel LLL algorithm. In: Proceedings of the fourth international C* conference on computer science and software engineering, pp 93–101Backes W, Wetzel S (2011) Parallel lattice basis reduction—the road to many-core. In: IEEE 13th international conference on high performance computing and communications (HPCC)Ahmad U, Amin A, Li M, Pollin S, Van der Perre L, Catthoor F (2011) Scalable block-based parallel lattice reduction algorithm for an SDR baseband processor. In: 2011 IEEE international conference on communications (ICC)Villard G (1992) Parallel lattice basis reduction. In: Papers from the international symposium on symbolic and algebraic computation (ISSAC’92). ACM, New YorkDomene F, Józsa CM, Vidal AM, Piñero G, Gonzalez A (2013) Performance analysis of a parallel lattice reduction algorithm on many-core architectures. In: Proceedings of the 13th international conference on computational and mathematical methods in science and engineeringGestner B, Zhang W, Ma X, Anderson DV (2008) VLSI implementation of a lattice reduction algorithm for low-complexity equalization. In: 4th IEEE international conference on circuits and systems for communications (ICCSC 2008), pp 643–647Burg A, Seethaler D, Matz G (2007) VLSI implementation of a lattice-reduction algorithm for multi-antenna broadcast precoding. In: IEEE international symposium on circuits and systems (ISCAS 2007), pp 673–676Bruderer L, Studer C, Wenk M, Seethaler D, Burg A (2010) VLSI implementation of a low-complexity LLL lattice reduction algorithm for MIMO detection. In: Proceedings of 2010 IEEE international symposium on circuits and systems (ISCAS

¿Cuánta desigualdad en exposición a alta polución por PM10 es demasiada para considerarla ambientalmente injusta? Una evaluación para grupos vulnerables en dos grandes ciudades españolas

Inequality in the environmental conditions or burden (negative externalities, hazards, discomfort, etc.) between places and people is an issue of growing interest. Many of works, using a variety of approaches, conclude that there is often discrimination and injustice. However, from the public decision-making and governance perspective, one question needs a clear answer: how much inequality is there? Is this too much, and therefore unfair, and does it justify public action? This paper looks at this question in a case study on the threat posed by air pollution in Madrid and Barcelona (Spain), by examining the spatial distribution of several vulnerable population groups and their potential exposure to high concentrations of PM10 in the atmosphere, and using an affordable method involving GIS and statistical techniques. Adopting an explicitly impartial operating criterion makes it possible to measure the amount of inequality for each population group and determine more objectively if it significantly exceeds the baseline criterion. This would make it more accurate for citizens and decision-makers alike to better assess the possible inequitiesLas desigualdades en la afección o carga ambiental (externalidades negativas, peligros, malestar, etc.) entre lugares y personas son un tema de creciente interés. Se han publicado abundantes estudios, utilizando métodos diversos, en los que se concluye que, a menudo, existe discriminación e inequidad. Ahora bien, desde el punto el punto de vista de la formación de decisiones públicas y de la gobernanza una pregunta sigue siendo necesario responder con claridad: cuánta desigualdad existe y si ésta es demasiada para ser calificada de injusta y justificar, por tanto, la acción pública. En este artículo se aborda esa cuestión a partir de un estudio de caso relativo al peligro por polución del aire en Madrid y Barcelona (España). A tal fin se examina la distribución espacial de varios grupos de población vulnerables y su exposición potencial a alta concentración de PM10 en la atmósfera, usando un método razonable que implica el uso de SIG y técnicas estadísticas. La adopción de un criterio operativo y explícito de imparcialidad posibilita medir la cantidad de desigualdad para cada grupo de población y determinar si ésta excede significativamente al criterio de referencia. Ello facilita una valoración más certera de la situación por los ciudadanos y los decisores públicosThis research was supported by the Spanish Ministry of Economy, Industry and Competitiveness project grant CSO2014-55535-

Sobre el papel de la programación paralela en los nuevos planes de estudios de informática

La difusión reciente de los sistemas paralelos hace que la programación paralela haya adquirido gran importancia, y dentro del proceso de reforma de los planes de estudios deberíamos plantearnos darle la importancia que realmente tiene. Los ingenieros en informática trabajan con estos sistemas y tienen que desarrollar software para ellos, por lo que no puede aducirse que es un tipo de programación complejo para no incluirlo o relegarlo de los estudios. Además, para obtener las máximas prestaciones de estos sistemas es necesario estudiar análisis y diseño de algoritmos paralelos. Este trabajo pretende motivar la discusión sobre cómo incluir los contenidos de programación y algoritmos paralelos. En nuestra opinión una buena opción sería incluir la programación paralela como parte de asignaturas de programación, junto con alguna asignatura específica de paralelismo.Peer Reviewe

OBIA System for Identifying Mesoscale Oceanic Structures in SeaWiFS and MODIS-Aqua Images

The ocean covers over 70% of the surface of our planet and plays a key role in the global climate. Most ocean circulation is mesoscale (scales of 50–500 km and 10–100 days), and the energy in mesoscale circulation is at least one order of magnitude greater than general circulation; therefore, the study of mesoscale oceanic structures (MOS) is crucial to ocean dynamics, making it especially useful for analyzing global changes. The detection of MOS, such as upwellings or eddies, from satellites images is significant for marine environmental studies and coastal resource management. In this paper, we present an object-based image analysis (OBIA) system which segments and classifies regions contained in sea-viewing field-of-view sensor (SeaWiFS) and Moderate Resolution Imaging Spectro-radiometer (MODIS)-Aqua sensor satellite images into MOS. After color clustering and hierarchical data format (HDF) file processing, the OBIA system segments images and extracts image descriptors, producing primary regions. Then, it merges regions, recalculating image descriptors for MOS identification and definition. First, regions are labeled by a human-expert, who identifies MOS: upwellings, eddies, cool, and warm eddies. Labeled regions are then classified by learning algorithms (i.e., decision tree, Bayesian network, artificial neural network, genetic algorithm, and near neighbor algorithm) from selected features. Finally, the OBIA system enables images to be queried from the user interface and retrieved by means of fuzzy descriptors and oceanic structures. We tested our system with images from the Canary Islands and the North West African coast

A location-based approach to the classification of mesoscale oceanic structures in SeaWiFS and Aqua-MODIS images of Northwest Africa

This study presents a different approach to the classification of Mesoscale Oceanic Structures (MOS) present in the Northwest African area, based on their location. The main improvement stems from the partition of this area in four large zones perfectly differentiated by their morphological characteristics, with attention to seafloor topography and coastal relief. This decomposition makes it easier to recognize structures under adverse conditions, basically the presence of clouds partly hiding them. This is observed particularly well in upwellings, which are usually very large structures with a different morphology and genesis in each zone. This approach not only improves the classification of the upwellings, but also makes it possible to analyse changes in the MOS over time, thereby improving the prediction of its morphological evolution. To identify and label the MOS classified in the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Aqua-MODIS (Moderate Resolution Imaging Spectroradiometer) chlorophyll-a and temperature images, we used a tool specifically designed by our group for this purpose and which has again shown its validity in this new proposal