Reverberation time estimation on the ACE corpus using the SDD method

Reverberation Time (T60) is an important measure for characterizing the properties of a room. The author's T60 estimation algorithm was previously tested on simulated data where the noise is artificially added to the speech after convolution with a impulse responses simulated using the image method. We test the algorithm on speech convolved with real recorded impulse responses and noise from the same rooms from the Acoustic Characterization of Environments (ACE) corpus and achieve results comparable results to those using simulated data.Comment: In Proceedings of the ACE Challenge Workshop - a satellite event of IEEE-WASPAA 2015 (arXiv:1510.00383

Export Dynamics in Colombia: Transactions Level Evidence

We examine Colombian export transaction data from customs records in several dimensions. We begin with some basic statistics on the number and frequency of export transactions by a firm, overall and across individual markets. We then decompose the variation in overall exports into the number of transactions and the size of the average transaction, both at the aggregate level and for individual firms to explore gravity equations, where the patterns of exports and numbers of transactions are related to the distance with respect to the destination. The analysis is carried out both at the aggregate and the firm level. Then we explore the relationship between patterns of transactions numbers and shipment modes. Our results show great heterogeneity in the patterns of frequency and number of transactions across firms; the average firm sent about 75 shipments abroad in 2005, while the firm with largest number of transactions that same year dispatched more than 26,000 shipments. Moreover, while close to 35% of firms in the sample report a single export transaction over the period, for most firms with multiple transactions the average span between two transactions is less than a month. Part of this heterogeneity is shown to be related to the distance with respect to the destination market: firms exporting to more distant destinations make less frequent shipments than firms exporting to markets that are closer. This suggests that there are fixed costs per shipment inducing declining marginal cost of higher shipment volume. These patterns imply that, at the aggregate level, transactions numbers are the primary source of variation in exports. The variability in the numbers of transactions also explains an important part of the well-known negative relationship between aggregate exports and distance to a specific destination.Export transaction frequency; fixed shipment costs and scale economies in transportation; destination distance, average shipment volume and number of shipments. Classification JEL: F10; F12; F14.

An Analysis of the Marketing Practices of Selected Snowmobile Companies in North America

This thesis describes and analyzes the marketing practices of snowmobile companies in North America. The data were obtained principally from a review of related literature and from structured interviews with representatives from selected snowmobile companies in North America. The main topics discussed in the thesis are: consumer attitudes, channels of distribution, methods of physical distribution, pricing methods and policies, advertising methods and sales promotion. Snowmobiles were purchased primarily for personal pleasure, racing, and family pleasure. Three major characteristics considered by consumers in choosing a brand of snowmobile were the dependability and reliability of the snowmobile, the quality of the construction of the snowmobile, and the availability of parts and service. The channels of distribution employed by snowmobile companies were the manufacturer-distributor-retailer-consumer channel, manufacturer- retailer-consumer channel, and the manufacturer-distributor channel. Twenty-one snowmobile companies employed the manufacturer-distributor- consumer-retailer channel. Four methods of transporting snowmobiles were trucks, railroads, ships, and airplanes. Trucks were employed by all of the snowmobile companies surveyed to transport snowmobiles. Cost-plus pricing was employed by sixteen of the snowmobile companies surveyed for the determination of prices for snowmobiles. Trade, quantity, cash, and seasonal discounts were granted to middlemen. The mean advertising expenditure of the snowmobile companies surveyed was 5.2 percent of the yearly gross revenue. Magazines were the most commonly used advertising medium. Television was adjudged to be the most effective advertising medium for snowmobile companies. All of the snowmobile companies assisted their middlemen in numerous sales promotion activities

Export Dynamics in Colombia: Firm-Level Evidence

Using transactions-level customs data from Colombia, we study firm-specific export patterns over the period 1996-2005. Our data allow us to track firms' entry and exit into and out of individual destination markets, as well as their revenues from selling there. We find that, in a typical year, nearly half of all Colombian exporters were not exporters in the previous year. These new exporters tend to be extremely small in terms of their overall contribution to export revenues, and most do not continue exporting in the following year. Hence export sales are dominated by a small number of very large and stable exporters. Nonetheless, out of each cohort of new exporters, a fraction of firms go on to expand their foreign sales very rapidly, and over the period of less than a decade, these successful new exporters account for almost half of total export expansion. Finally, we find that new exporters begin in a single foreign market and, if they survive, gradually expand into additional destinations. The geographic expansion paths they follow, and their likelihood of survival as exporters, depend on their initial destination market.