EXIT chart analysis of iteratively detected and SVD-assisted broadband MIMO-BICM schemes

In this contribution the number of activated MIMO layers and the number of bits per symbol are jointly optimized under the constraint of a given fixed data throughput and integrity. In general, non-frequency selective MIMO links have attracted a lot of research and have reached a state of maturity. By contrast, frequency selective MIMO links require substantial further research, where spatio-temporal vector coding (STVC) introduced by Raleigh seems to be an appropriate candidate for broadband transmission channels. In analogy to bit-interleaved coded irregular modulation, a broadband MIMO-BICM scheme is introduced, where different signal constellations and mappings are used within a single codeword. Extrinsic Information Transfer (EXIT) charts are used for analyzing and optimizing the convergence behaviour of the iterative demapping and decoding. Our results show that in order to achieve the best bit-error rate, not necessarily all MIMO layers have to be activated

Modulation-mode assignment for SVD-assisted and iteratively detected downlink multiuser MIMO transmission schemes

In this contribution we jointly optimize the number of multiple-input multiple-output (MIMO) layers and the number of bits per symbol within an iteratively-detected multiuser MIMO downlink (DL) transmission scheme under the constraint of a given fixed data throughput and integrity. Instead of treating all the users jointly as in zero-forcing (ZF) multiuser transmission techniques, the investigated singular value decomposition (SVD) assisted DL multiuser MIMO system takes the individual user's channel characteristics into account. In analogy to bit-interleaved coded irregular modulation, we introduce a MIMO-BICM scheme, where different user-specific signal constellations and mapping arrangement were used within a single codeword. Extrinsic information transfer (EXIT) charts are used for analyzing and optimizing the convergence behaviour of the iterative demapping and decoding. Our results show that in order to achieve the best bit-error rate, not necessarily all user-specific MIMO layers have to be activate

Modulation-mode and power-assignment for SVD-assisted downlink multiuser MIMO systems

Multiuser multiple-input multiple-output (MIMO) downlink (DL) transmission schemes experience both multiuser interference as well as inter-antenna interference. However, instead of treating all the users jointly as in zero-forcing (ZF) multiuser transmission techniques, the investigated singular value decomposition (SVD) assisted DL multiuser MIMO system takes the individual user's channel characteristics into account. The performed joint optimization of the number of activated MIMO layers and the number of bits per symbol along with the appropriate allocation of the transmit power shows that not necessarily all user-specific MIMO layers has to be activated in order to minimize the overall BER under the constraint of a given fixed data throughput

Performance Analysis of SVD-assisted Downlink Multiuser MIMO Systems

Multiuser multiple-input multiple-output (MIMO) downlink (DL) transmission schemes experience both multiuser interference as well as inter-antenna interference. Instead of treating all the users jointly as in zero-forcing (ZF) multiuser transmission techniques, the investigated singular value decomposition (SVD) assisted DL multiuser MIMO system takes the individual user’s channel characteristics into account. This translates to a choice of modulation constellation and transmitter power and, in our proposed system, to a choice of number of activated user-specific MIMO layers. The performed joint optimization of the number of activated MIMO layers and the number of bits per symbol along with the appropriate allocation of the transmit power shows that not necessarily all user-specific MIMO layers has to be activated in both frequency-selective and non-frequency selective MIMO channels in order to minimize the overall BER under the constraint of a given fixed data throughput

Modulation-mode and power-assignment for SVD-and GMD-assisted downlink MIMO systems

Multiuser multiple-input multiple-output (MIMO) downlink (DL) transmission schemes experience both multiuser interference (MUI) as well as inter-antenna interference. However, instead of treating all the users jointly as in zero-forcing (ZF) multiuser transmission techniques, the investigated singular value decomposition (SVD) and geometric mean decomposition (GMD) assisted DL multiuser MIMO systems take the individual user's channel characteristics into account. The performed joint optimization of the number of activated MIMO layers and the number of bits per symbol along with the appropriate allocation of the transmit power shows that not necessarily all user-specific MIMO layers have to be activated in order to minimize the overall BER under the constraint of a fixed data throughpu

Estudio, dimensionado y validación de una bomba volumétrica

Automatisation du procès pour faire un dimensionnement optimal des engrenages, en faisant minimale le volume mort dans l’engrènement de deux engrenages. Etude appliqué à une pompe à engrenages.Ingeniería Industria

El patriotismo constitucional: reflexiones en el vigésimo quinto aniversario de la Constitución española

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Preparation and Characterisation of Binder-Free All-Cellulose Composites

The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the authorA recent emerging concept of all-cellulose composites within the field of environmentally friendly materials has received increasing attention. The main advantage of these materials is the lack of using additional bonding agents such as polymer resins as in the case of e.g. phenolic resin based panel products or natural fibre reinforced plastics that increase their environmental impact. Two different routes for the production of all-cellulose composites have been followed. The obtained materials were characterised by scanning electron microscopy, X-ray diffraction, flexure and tensile mechanical tests, thermogravimetric analysis, pycnometry and water absorption tests. The first strategy makes use of the selective dissolution method where the cellulose fibre skins are partially dissolved to form a matrix phase that bonds the fibres together, while the strong core fibres are maintained and impart a reinforcing effect to the composites. The influence of the dissolution time, activation time and the fibre source were assessed. It was found that a dissolution time of 18 h led to materials with the best overall mechanical performance (5.5 GPa and 145 MPa for Young’s modulus and tensile strength, respectively), as this time allowed for the dissolution of a sufficient amount of fibre surface to obtain good interfacial bonding between fibres, while keeping a considerable amount of remaining fibre cores that provide a strong reinforcement to the composite, leading to materials that outperform natural fibres reinforced polypropylene composites. Still, the previous methodology has the drawback of using chemical substances of high environmental impact (solvents). In order to overcome this, a new concept in the production of all-cellulose composites is proposed in this work, which makes use of the intrinsic bonding capability between cellulose fibres to enhance the hydrogen bond network in order to produce materials of good mechanical performance. A new experimental procedure was developed, based on the refinement Abstract 5 of cellulose fibres in order to increase their specific surface area, thus increasing the interfibre bonding capability, and achieving materials with excellent mechanical properties, up to 17 GPa and 119 MPa for flexural modulus and strength, respectively, and low water absorption. These new high-performing environmentally friendly materials are based on renewable resources and are 100% recyclable and biodegradable.Financial support from the Engineering and Physical Sciences Research Council through a Technology Strategy Board project REFLECT no. MATH1E2R, under the Design & Manufacture of Sustainable Products Call, is gratefully acknowledged

Giant Bilateral Renal Angiomyolipomas and Lymphangioleiomyomatosis Presenting after Two Successive Pregnancies Successfully Treated with Surgery and Rapamycin

We report the case of a 25-year-old woman who presented with abdominal and flank pain with two successive pregnancies and was diagnosed of giant bilateral renal AMLs and pulmonary LAM associated with TSC in the post-partum of her second pregnancy. This case illustrates that in women with TSC rapid growth from renal AMLs and development of LAM may occur with successive pregnancies. It also stresses the potential for preservation of renal function despite successive bilateral renal surgery of giant AMLs. Moreover, the treatment with a low-dose rapamycin may be an option for LAM treatment. Finally, a low-dose rapamycin may be considered as an adjuvant treatment together to kidney-sparing conservative surgery for renal AMLs

Globalización: universalidad y fraccionamiento en los procedimientos de insolvencia. Un análisis desde el Derecho Internacional Privado

El contenido de este artículo forma parte de la Conferencia pronunciada en el Curso de Verano sobre la Aplicación de la Ley Concursal dirigido por el departamento de Derecho Privado de la Universidad de Alcalá, organizado en la Facultad de Derecho de la citada Universidad, que tuvo lugar el día 2 de julio de 2009En este trabajo se abordan los dos modelos existentes en el ámbito concursal, el universal que propugna la apertura de un único procedimiento de insolvencia, que abarca la totalidad de los bienes del concursado, y el territorial, que permite la apertura de varios procedimientos allí dónde el deudor tiene sus bienes. En el caso español se opta por un modelo mixto tanto en la normativa comunitaria, Reglamento 1346/2000 como en la Ley interna. Además se analiza el funcionamiento y los problemas de interpretación del Reglamento y la aplicación de la Ley 22/2003 en concursos extracomunitarios.In this study both existing models are approached in the area of the insolvency, the universal one that supports the opening of the only procedure of insolvency, which includes the totality of the patrimony of the debtor, and the territorial one, which allows the opening of several procedures there where the debtor has his patrimony. In the Spanish case, it is chosen by a model of compound so much in the community regulation, R1346/2000 like in the internal Law. In addition there is analyzed the functioning and the problems of interpretation of the community regulation and the application of the Law 22/2003 in procedures of insolvency out of de community area