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

Materials and methods for tagging purse seine and baitboat caught tunas

ENGLISH: The percentages of return of purse seine-tagged yellowfin and baitboat- tagged yellowfin and skipjack subjected to various combinations of treatments were tested statistically to determine the effects of the treatments. For yellowfin the precentages of return differed among sets or dates of release, and were higher for double-tagged fish, larger fish, and fish released soonest during each set. For skipjack the percentages of return differed among dates of release, and were higher for single-tagged fish and fish tagged in plastic-covered cradles. SPANISH: Los porcentajes de retorno de aleta amarilla marcado en barcos cerqueros y los de aleta amarilla y barrilete marcados en los de carnada sometidos a varias combinaciones de tratamientos fueron probados estadísticamente para determinar los efectos de los tratamientos. Con respecto al aleta amarilla los porcentajes de retorno fueron diferentes entre los lances o fechas de liberación, y fueron más altos para los peces con doble marca, peces de más talla y peces liberados lo más pronto durante cada lance. Los porcentajes de retorno del barrilete fueron diferentes entre las fechas de liberación, y fueron más altos para peces con una sola marca y peces marcados en cunas cubiertas con plástico. (PDF contains 41 pages.

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

A review of the Japanese longline fishery for tunas and billfishes in the Eastern Pacific Ocean, 1967-1970

ENGLISH: This report deals with the Japanese longline fishery for tunas and billfishes from 1967 through 1970, extending the studies made by Kume and Joseph (1969a, 1969b). The distribution of effort and catch is discussed and evaluated, and the changes in apparent abundance are examined. An analysis is made of the sexual maturity and size composition of the fish, and a brief comparison of the size composition of the catches from the longline and the surface fisheries is included. SPANISH: Este informe analiza la pesca palangrera japonesa de atunes y peces espada desde 1967 a 1970, ampliando los estudios hechos por Kume y Joseph (1969a, 1969b). Se discute y avalúa la distribución del esfuerzo y la captura, y los cambios en la abundancia aparente. Se hace un análisis de la madurez sexual y de la composición de talla de los peces y una breve comparación entre la composición de talla de los peces capturados en la pesca palangrera y la epípelágíca. (PDF contains 166 pages.

A review of IATTC research on the early life history and reproductive biology of scombrids conducted at the Achotines Laboratory from 1985 to 2005

English: For nearly a century, fisheries scientists have studied marine fish stocks in an effort to understand how the abundances of fish populations are determined. During the early lives of marine fishes, survival is variable, and the numbers of individuals surviving to transitional stages or recruitment are difficult to predict. The egg, larval, and juvenile stages of marine fishes are characterized by high rates of mortality and growth. Most marine fishes, particularly pelagic species, are highly fecund, produce small eggs and larvae, and feed and grow in complex aquatic ecosystems. The identification of environmental or biological factors that are most important in controlling survival during the early life stages of marine fishes is a potentially powerful tool in stock assessment. Because vital rates (mortality and growth) during the early life stages of marine fishes are high and variable, small changes in those rates can have profound effects on the properties of survivors and recruitment potential (Houde 1989). Understanding and predicting the factors that most strongly influence pre-recruit survival are key goals of fisheries research programs. Spanish: Desde hace casi un siglo, los científicos pesqueros han estudiado las poblaciones de peces marinos en un intento por entender cómo se determina la abundancia de las mismas. Durante la vida temprana de los peces marinos, la supervivencia es variable, y el número de individuos que sobrevive hasta las etapas transicionales o el reclutamiento es difícil de predecir. Las etapas de huevo, larval, y juvenil de los peces marinos son caracterizadas por tasas altas de mortalidad y crecimiento. La mayoría de los peces marinos, particularmente las especies pelágicas, son muy fecundos, producen huevos y larvas pequeños, y se alimentan y crecen en ecosistemas acuáticos complejos. La identificación los factores ambientales o biológicos más importantes en el control de la supervivencia durante las etapas tempranas de vida de los peces marinos es una herramienta potencialmente potente en la evaluación de las poblaciones. Ya que las tasas vitales (mortalidad y crecimiento) durante las etapas tempranas de vida de los peces marinos son altas y variables, cambios pequeños en esas tasas pueden ejercer efectos importantes sobre las propiedades de los supervivientes y el potencial de reclutamiento (Houde 1989). Comprender y predecir los factores que más afectan la supervivencia antes del reclutamiento son objetivos clave de los programas de investigación pesquera

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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