3 resultados para Time-memory attacks

em Repositório digital da Fundação Getúlio Vargas - FGV


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Chambers (1998) explores the interaction between long memory and aggregation. For continuous-time processes, he takes the aliasing effect into account when studying temporal aggregation. For discrete-time processes, however, he seems to fail to do so. This note gives the spectral density function of temporally aggregated long memory discrete-time processes in light of the aliasing effect. The results are different from those in Chambers (1998) and are supported by a small simulation exercise. As a result, the order of aggregation may not be invariant to temporal aggregation, specifically if d is negative and the aggregation is of the stock type.

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This paper investigates the presence of long memory in financiaI time series using four test statistics: V/S, KPSS, KS and modified R/S. There has been a large amount of study on the long memory behavior in economic and financiaI time series. However, there is still no consensus. We argue in this paper that spurious short-term memory may be found due to the incorrect use of data-dependent bandwidth to estimating the longrun variance. We propose a partially adaptive lag truncation procedure that is robust against the presence of long memory under the alternative hypothesis and revisit several economic and financiaI time series using the proposed bandwidth choice. Our results indicate the existence of spurious short memory in real exchange rates when Andrews' formula is employed, but long memory is detected when the proposed lag truncation procedure is used. Using stock market data, we also found short memory in returns and long memory in volatility.

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Event Marketing represents a common promotional strategy that involves direct contact between brands and consumers at special events, namely concerts, festivals, sporting events and fairs. Brands have been investing in sponsorship as a means of associating themselves with particular events, essentially with the goal to enhance brand image and brand awareness. Interestingly, the response of consumers to event marketing has not yet been fully understood. This dissertation fills this gap. More specifically, it intends to determine the extent to which sponsoring brands at events favors brand awareness (recall and recognition) and how it relates to brand attitude. Based on three Portuguese music festivals, two studies were conducted to ascertain event sponsorship’s impact on consumer memory, notably Brand Recall and Brand Recognition, and correlation with attitudes towards the brands such as familiarity and liking. The key findings of these studies show that recognition is much higher for those respondents who attended the festivals, presenting a score of 73,9%, in comparison with recall, presenting a much lower score of 37,5%. Further, and surprisingly, it suggests that the ability to recall and recognize sponsoring brands is not associated to consumer attitudes towards the brands. Instead, it relates to the time consumers dedicated to these particular events, that is, the number of music festivals attended.