Joint multiple dictionary learning for tensor sparse coding

Traditional dictionary learning algorithms are used for finding a sparse representation on high dimensional data by transforming samples into a one-dimensional (1D) vector. This 1D model loses the inherent spatial structure property of data. An alternative solution is to employ Tensor Decomposition for dictionary learning on their original structural form —a tensor— by learning multiple dictionaries along each mode and the corresponding sparse representation in respect to the Kronecker product of these dictionaries. To learn tensor dictionaries along each mode, all the existing methods update each dictionary iteratively in an alternating manner. Because atoms from each mode dictionary jointly make contributions to the sparsity of tensor, existing works ignore atoms correlations between different mode dictionaries by treating each mode dictionary independently. In this paper, we propose a joint multiple dictionary learning method for tensor sparse coding, which explores atom correlations for sparse representation and updates multiple atoms from each mode dictionary simultaneously. In this algorithm, the Frequent-Pattern Tree (FP-tree) mining algorithm is employed to exploit frequent atom patterns in the sparse representation. Inspired by the idea of K-SVD, we develop a new dictionary update method that jointly updates elements in each pattern. Experimental results demonstrate our method outperforms other tensor based dictionary learning algorithms.

International transmission mechanisms and contagion in housing markets

This paper explores international transmission mechanism and its role in contagion effect in the housing markets across six major Asian cities. The analysis is based on the identification of house price diffusion effects through a global vector autoregressive (GVAR) model estimated using quarterly data for six major Asian cities (Hong Kong, Tokyo, Seoul, Singapore, Taipei and Bangkok) from 1991Q1 to 2011Q2. The empirical results indicate that the open economies heavily relying on international trade such as Singapore, Japan (Tokyo), Taiwan (Taipei) and Thailand (Bangkok) show positive correlations between the economy's openness and house prices, which is consistent with the Balassa–Samuelson hypothesis. Interestingly, some region-specific conditions also appear to play important roles as determinants of house price movements, which may be driven by restrictive housing policies and demand–supply imbalances such as Singapore and Bangkok. These results are reasonably robust across several model specifications. The findings bear significant implications for formulation of investment strategy and public policies.

Why the hand motion proceeds the target in tracking experiment?

In the present study, to shed light on a role of positional error correction mechanism and prediction mechanism in the proactive control discovered earlier, we carried out a visual tracking experiment, in which the region where target was shown, was regulated in a circular orbit. Main results found in this research were following. Recognition of a time step, obtained from the environmental stimuli, is required for the predictive function. The period of the rhythm in the brain obtained from environmental stimuli is shortened about 10%, when the visual information is cut-off. The shortening of the period of the rhythm in the brain accelerates the motion as soon as the visual information is cut-off, and lets the hand motion precedes the target motion. Although the precedence of the hand in the blind region is reset by the environmental information when the target enters the visible region, the hand precedes in average the target when the predictive mechanism dominates the error-corrective mechanism.

Reading aloud in high schools: students and teachers across the curriculum

Reading aloud is apparently an indispensible part of teaching. Nevertheless, little is known about reading aloud across the curriculum by students and teachers in high schools. Nor do we understand teachers’ attitudes towards issues such as error correction, rehearsal time, and selecting students to read. A survey of 360 teachers in England shows that, although they have little training in reading aloud, they are extremely confident. Reading aloud by students and teachers is strongly related, and serves to further understanding rather than administrative purposes or pupils’ enjoyment. Unexpectedly, Modern Language teachers express views that set them apart from other subjects.

O Impacto do Risco Inflacionário sobre o Juros no Brasil

Esta dissertação analisa a conexão existente entre o mercado de dívida pública e a política monetária no Brasil. Com base em um Vetor Auto-Regressivo (VAR), foram utilizadas duas proxies alternativas de risco inflacionário para mostrar que choques positivos no risco inflacionário elevam tanto as expectativas de inflação do mercado quanto os juros futuros do Swap Pré x DI. Em seguida, com base em modelo de inconsistência dinâmica de Blanchard e Missale (1994) e utilizando a metodologia de Johansen, constatou-se que um aumento nos juros futuros diminui a maturidade da dívida pública, no longo prazo. Os resultados levam a duas conclusões: o risco inflacionário 1) dificulta a colocação de títulos nominais (não-indexados) no mercado pelo governo, gerando um perfil de dívida menos longo do que o ideal e 2) torna a política monetária mais custosa.

O impacto do risco inflacionário sobre os juros no Brasil

Esta dissertação analisa a conexão existente entre o mercado de dívida pública e a política monetária no Brasil. Com base em um Vetor Auto-Regressivo (VAR), foram utilizadas duas proxies alternativas de risco inflacionário para mostrar que choques positivos no risco inflacionário elevam tanto as expectativas de inflação do mercado quanto os juros futuros do Swap Pré x DI. Em seguida, com base em modelo de inconsistência dinâmica de Blanchard e Missale (1994) e utilizando a metodologia de Johansen, constatou-se que um aumento nos juros futuros diminui a maturidade da dívida pública, no longo prazo. Os resultados levam a duas conclusões: o risco inflacionário 1) dificulta a colocação de títulos nominais (não-indexados) no mercado pelo governo, gerando um perfil de dívida menos longo do que o ideal e 2) torna a política monetária mais custosa.

Temporal causality between the exchange rate and the trade balance : the case of Brazil

The paper assesses the impact of intemational relative prices and domestic expenditure variables on Brazil' s foreign trade performance in the first half of the 1990s. It has been argued that the appreciation of the Real since 1994 has had a detrimental impact of the country's trade balance. However, using temporal precedence analysis, our results do not indicate that the trade balance is strongly affected by intemational rei ative prices, such as the exchange rate. Instead, domestic expenditure variables appear to be more powerful determinant of the country' s trade performance in recent years. Granger and error correction causality techniques are used to determine temporal precedence between the trade balance and the exchange rate in the period under examination. Our findings shed light on the debate over the sustainability of recent exchange rate-anchored macroeconomic stabilisation programmes, which is a topic that has encouraged a lot of debate among academics and practitioners.

Earnings dynamics and inequality in Venezuela: 1995-1997

In this paper, we decompose the variance of logarithmic monthly earnings of prime age males into its permanent and transitory components, using a five-wave rotating panel from the Venezuelan “Encuesta de Hogares por Muestreo” from 1995 to 1997. As far as we know, this is the first time a variance components model is estimated for a developing country. We test several specifications and find that an error component model with individual random effects and first order serially correlated errors fits the data well. In the simplest model, around 22% of earnings variance is explained by the variance of permanent component, 77% by purely stochastic variation and the remaining 1% by serial correlation. These results contrast with studies from industrial countries where the permanent component is predominant. The permanent component is usually interpreted as the results of productivity characteristics of individuals whereas the transitory component is due to stochastic perturbations such as job and/or price instability, among others. Our findings may be due to the timing of the panel when occurred precisely during macroeconomic turmoil resulting from a severe financial crisis. The findings suggest that earnings instability is an important source of inequality in a region characterized by high inequality and macroeconomic instability.

Effect of price and in-store promotion on sales: a study of distinct regions in an emerging market

Increasing competition caused by globalization, high growth of some emerging markets and stagnation of developed economies motivate Consumer Packaged Goods (CPGs) manufacturers to drive their attention to emerging markets. These companies are expected to adapt their marketing activities to the particularities of these markets in order to succeed. In a country classified as emerging market, regions are not alike and some contrasts can be identified. In addition, divergences of marketing variables effect can also be observed in the different retail formats. The retail formats in emerging markets can be segregated in chain self-service and traditional full-service. Thus, understanding the effectiveness of marketing mix not only in country aggregated level data can be an important contribution. Inasmuch as companies aim to generate profits from emerging markets, price is an important marketing variable in the process of creating competitive advantage. Along with price, promotional variables such as in-store displays and price cut are often viewed as temporary incentives to increase short-term sales. Managers defend the usage of promotions as being the most reliable and fastest manner to increase sales and then short-term profits. However, some authors alert about sales promotions disadvantages; mainly in the long-term. This study investigates the effect of price and in-store promotions on sales volume in different regions within an emerging market. The database used is at SKU level for juice, being segregated in the Brazilian northeast and southeast regions and corresponding to the period from January 2011 to January 2013. The methodological approach is descriptive quantitative involving validation tests, application of multivariate and temporal series analysis method. The Vector-Autoregressive (VAR) model was used to perform the analysis. Results suggest similar price sensitivity in the northeast and southeast region and greater in-store promotion sensitivity in the northeast. Price reductions show negative results in the long-term (persistent sales in six months) and in-store promotion, positive results. In-store promotion shows no significant influence on sales in chain self-service stores while price demonstrates no relevant impact on sales in traditional full-service stores. Hence, this study contributes to the business environment for companies wishing to manage price and sales promotions for consumer brands in regions with different features within an emerging market. As a theoretical contribution, this study fills an academic gap providing a dedicated price and sales promotion study to contrast regions in an emerging market.

Egg production curve fitting using nonlinear models for selected and nonselected lines of White Leghorn hens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracterização espectral de áreas de gramíneas forrageiras infectadas com a doença mela-das-sementes da braquiária por meio de imagens CCD/CBERS-2

Imagens CCD/CBERS-2, nas bandas espectrais CCD2, CCD3 e CCD4, dos anos de 2004 e 2005, de Mirante do Paranapanema - SP, foram transformadas em reflectância de superfície usando o modelo 5S de correção atmosférica e normalizadas radiometricamente. O objetivo principal foi caracterizar espectralmente áreas de pastagens de Brachiaria brizantha em fase de florescimento, isentas e infectadas com a doença mela-das-sementes da braquiária, possibilitando a sua detecção por meio da comparação entre os valores de reflectância de superfície denominada de Fator de Reflectância Bidirecional de Superfície (FRBS). Teve-se, também, o objetivo de avaliar a eficácia das imagens CCD/CBERS-2 para a obtenção de respostas espectrais de pastagens. Os dosséis sadios e doentes da Brachiaria brizantha foram identificados por meio da análise dos valores de reflectância e dos dados observados no Índice de Estresse Hídrico Acumulativo Relativo da Cultura (ACWSI) obtidos na área de estudo. Os resultados indicaram que as principais diferenças foram a diminuição da reflectância na banda CCD3 e o aumento da reflectância na banda CCD4 nas áreas doentes. A metodologia empregada com o uso de dados do sensor CCD/CBERS-2, associados ao ACWSI, mostrou-se eficaz para discriminar dosséis infectados com a mela-das-sementes da braquiária.