A DHT-Based Multicarrier Modulation System with Pairwise ML Detection

This paper presents a complex-valued discrete multicarrier modulation (MCM) system based on the real-valued discrete Hartley transform (DHT) and its inverse (IDHT). Unlike the conventional discrete Fourier transform (DFT), the DHT cannot diagonalize multipath fading channels due to its inherent properties, and this results in mutual interference between subcarriers of the same mirror-symmetrical pair. We explore this interference pattern in order to seek an optimal solution to utilize channel diversity for enhancing the bit error rate (BER) performance of the system. It is shown that the optimal channel diversity gain can be achieved via pairwise maximum likelihood (ML) detection, taking into account not only the subcarrier's own channel quality but also the channel state information of its mirror-symmetrical peer. Performance analysis indicates that DHT-based MCM can mitigate fast fading effects by averaging channel power gains of each mirror-symmetrical pair of subcarriers. Simulation results show that the proposed scheme has a substantial improvement in BER over the conventional DFT-based MCM system

El efecto de los letreros de información y la posición del diseño de la publicidad impresa en el comportamiento de compra: efecto moderador del conocimiento de la marca y el rango de precios

The purpose of this research is to discover the consumers’ buying behavior influence of information symbols in print advertisements, and also added the brand awareness and price range of the products as the interference, and to find out whether to increase or decrease the information symbols and page layout on purchasing behavior influence. A 3C electrical appliance retail channel in Taiwan has been applied as the research object, concentrating on the advertisement DM during the four promotions in 2013 and the sales volume. There were 1,196 product information and 136 3C electrical appliance brands. According to the variance analysis, the results indicated: First, some information symbols included the positive and negative effects on purchasing behavior; Second, overall, the interference effects only influenced low to medium brand awareness and low price range. In sum, the research generated both theoretical and practical implications and also provided future research advice.El propósito de esta investigación fue descubrir la influencia del comportamiento de compra de los consumidores de los símbolos de información en los anuncios impresos, y también agregó el conocimiento de la marca y el rango de precios de los productos como la interferencia, para averiguar si aumentar o disminuir la información, así como ver la influencia de los símbolos y el diseño de la página sobre el comportamiento de compra. Se ha aplicado un canal minorista de electrodomésticos 3C en Taiwán como objeto de investigación, concentrándose en el DM publicitario durante las cuatro promociones en 2013 y el volumen de ventas. Según el análisis de varianza, los resultados indicaron: Primero, algunos símbolos de información incluían los efectos positivos y negativos sobre el comportamiento de compra; En segundo lugar, en general, los efectos de interferencia solo influyeron en el conocimiento de la marca de bajo a medio y en el rango de precios bajo. En resumen, la investigación generó implicaciones tanto teóricas como prácticas y también brindó asesoramiento para futuras investigaciones

Two-Step Sintering of Ceramics with Constant Grain-Size, I. Y\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e

Isothermal and constant-grain-size sintering have been carried out to full density in Y2O3 with and without dopants, at as low as 40% of the homologous temperature. The normalized densification rate follows Herring’s scaling law with a universal geometric factor that depends only on density. The frozen grain structure, however, prevents pore relocation commonly assumed in the conventional sintering models, which fail to describe our data. Suppression of grain growth but not densification is consistent with a grain boundary network pinned by triple-point junctions, which have a higher activation energy for migration than grain boundaries. Long transients in sintering and grain growth have provided further evidence of relaxation and threshold processes at the grain boundary/triple point

DualTable: A Hybrid Storage Model for Update Optimization in Hive

Hive is the most mature and prevalent data warehouse tool providing SQL-like interface in the Hadoop ecosystem. It is successfully used in many Internet companies and shows its value for big data processing in traditional industries. However, enterprise big data processing systems as in Smart Grid applications usually require complicated business logics and involve many data manipulation operations like updates and deletes. Hive cannot offer sufficient support for these while preserving high query performance. Hive using the Hadoop Distributed File System (HDFS) for storage cannot implement data manipulation efficiently and Hive on HBase suffers from poor query performance even though it can support faster data manipulation.There is a project based on Hive issue Hive-5317 to support update operations, but it has not been finished in Hive's latest version. Since this ACID compliant extension adopts same data storage format on HDFS, the update performance problem is not solved. In this paper, we propose a hybrid storage model called DualTable, which combines the efficient streaming reads of HDFS and the random write capability of HBase. Hive on DualTable provides better data manipulation support and preserves query performance at the same time. Experiments on a TPC-H data set and on a real smart grid data set show that Hive on DualTable is up to 10 times faster than Hive when executing update and delete operations.Comment: accepted by industry session of ICDE201