Within Lake Clustering of High Resolution Satellite Retrievals: A Functional Data and Clustering Approach

No abstract available

Comment on "Effect of growth interruptions on the light emission and indium clustering of InGaN/GaN multiple quantum wells" [Appl. Phys. Lett. 79, 2594 (2001)]

This entry is a comment on "Effect of growth interruptions on the light emission and indium clustering

The Utilization of U.S. male labor, 1975-1992: Estimates of foregone work hours

The percentage of working-age men in the United States who were fully active in the labor market decreased over the 1975-1992 period ("fully active" means working 2080 hours in a year). Similarly, the extent to which men were less than fully active increased. When one considers the number of hours by which men fell short of the 2080 norm in 1992, it was as if 20 percent of them did not work at all in that year, up from 18 percent in 1975. However, because the least-productive workers were the ones most likely to be less than fully active and the most-productive were the ones least likely to be less than fully active, total productivity-weighted work hours did not fall by this large an amount. If men failed to work 2080 hours in a year, most likely it was because they did not work at all; men most often did not work at all because they could find no jobs. Data were from Current Population Surveys.

Recent trends in U.S. male work and wage patterns: An overview

This paper brings together figures on recent trends in the labor market activity and wages of working-age men in the United States over the 1967-1992 period. The data, which come from Current Population Surveys, reveal several important developments. Year-long joblessness, the percentage of men failing to participate in the labor force, and the proportion who were unemployed rose throughout the period. Part-time employment as a percentage of all forms of employment was also higher at the end of the period than at the beginning, and the average hours worked by full-time workers increased slightly. Finally, median and mean wages fell. None of the trends was due to changes in the racial, educational, and age composition of the male work force; in fact, if the racial/educational/age composition had remained the same over the period, labor market activity would have declined even further.

The concept of opportunity cost: Is it simple, fundamental or necessary?

Surveys by Ferraro and Taylor (2005) point to abysmal understandings of the concept of opportunity cost by US undergraduates, graduates and faculty, and raise important pedagogical and conceptual issues. One implication is that the concept is poorly taught in textbooks and classrooms, from which it follows that remedies are needed. Three further implications strongly influence the nature and extent of these remedies. These are that opportunity cost is not a simple concept but a difficult one, that it is not a fundamental economic concept but a subordinate one, and that graduates do not require a good understanding of the concept for successful careers as economists. This paper presents logical arguments supporting these propositions, and discusses their bearing on general strategies for dealing with the pedagogical problem

The permanent need for political economy

My purpose here is to offer, in hindsight, an assessment of the significance of the dispute in terms of its two underlying issues the nature of economics and the role of university ideals. I write as someone who was a student activist, both inside and outside official channels, from 1974 to 1977 during the first major phase of the dispute, who graduated with degrees in economics (BEc) and philosophy (BA) and who, supported by scholarships from Sydney University, took a doctorate in Economics at Cambridge prior to returning to Australia and an academic career

Development of a cantilever beam generator employing vibration energy harvesting

This paper details the development of a generator based upon a cantilever beam inertial mass system which harvests energy from ambient environmental vibrations. The paper compares the predicted results from Finite Element Analysis (FEA) of the mechanical behaviour and magnetic field simulations and experimental results from a generator. Several design changes were implemented to maximise the conversion of magnetic energy into generated power and a maximum power output of 17.8µW was achieved at a resonant frequency of 56.6Hz and an applied acceleration of 60mg (g = 9.81ms-2)

Testing for Market Power in Multiple-Input, Multiple-Output Industries: The Australian Grains and Oilseeds Industries

Recent empirical studies have found significant evidence of departures from competition in the input side of the Australian bread, breakfast cereal and margarine end-product markets. For example, Griffith (2000) found that firms in some parts of the processing and marketing sector exerted market power when purchasing grains and oilseeds from farmers. As noted at the time, this result accorded well with the views of previous regulatory authorities (p.358). In the mid-1990s, the Prices Surveillence Authority (PSA 1994)determined that the markets for products contained in the Breakfast Cereals and Cooking Oils and Fats indexes were "not effectively competitive"(p.14). The PSA consequently maintained price surveillence on the major firms in this product group. The Griffith result is also consistent with the large number of legal judgements against firms in this sector over the past decade for price fixing or other types of non-competitive behaviour. For example, bread manufacturer George Weston was fined twice during 2000 for non-competitive conduct and the ACCC has also recently pursued and won cases against retailer Safeway in grains and oilseeds product lines. Griffith obtained his results using highly aggregated data and a relatively simple empirical model. In this study we focus on confirming the earlier results by formally testing for competitive behaviour in the Australian grains and oilseeds industries using a more sophisticated empirical model and a less aggregated grains and oilseeds data set. We specify a general duality model of profit maximisation that allows for imperfect competition in both the input and output markets of the grains and oilseeds industries. The model also allows for variable-proportions technologies and can be regarded as a generalisation of several models appearing in the agricultural economics and industrial organisation literatures. Aggregate Australian data taken from the 1996-97 input-output tables are used to define the structure of the relevant industries, and time series data are used implement the model for thirteen grains and oilseeds products handled by seven groups of agents. The model is estimated in a Bayesian econometrics framework. Results are reported in terms of the characteristics of estimated probability distributions for demand and supply elasticities and indexes of market power. Our results suggest that there is a positive probability that: (a) flour and cereal food product manufacturers exert market power when purchasing wheat, barley, oats and triticale; (b) beer and malt manufacturers exert market power when purchasing wheat and barley; and (c) other food product manufacturers exert market power when purchasing wheat, barley, oats and triticale. What is interesting is that each of the transaction nodes where market power is indicated is one where a farm commodity is sold to a processing sector that is, the evidence suggests oligopsonistic behaviour by grains buyers. The wheat and barley industries seem to be especially disadvantaged by this type of market conduct. A related and equally interesting result is that there was no consistent evidence of market power in the downstream nodes of the data set relating to the sales of flour and other cereal foods, or the sale of bread and other bakery products. These transaction points are where legal judgements against suppliers have been made in the recent past. We have stated our results in quite cautious language, as there is much uncertainty surrounding our estimates. This stems partly from the lack of good quality data, so we suggest that one avenue for future research should be improving the collection and integrity of relevant data (especially including the retail and distributive nodes of the various markets).Industrial Organization, Marketing,

Optimal Data-Dependent Hashing for Approximate Near Neighbors

We show an optimal data-dependent hashing scheme for the approximate near neighbor problem. For an $n$-point data set in a $d$-dimensional space our data structure achieves query time $O(d n^{\rho+o(1)})$ and space $O(n^{1+\rho+o(1)} + dn)$, where $\rho=\tfrac{1}{2c^2-1}$ for the Euclidean space and approximation $c>1$. For the Hamming space, we obtain an exponent of $\rho=\tfrac{1}{2c-1}$. Our result completes the direction set forth in [AINR14] who gave a proof-of-concept that data-dependent hashing can outperform classical Locality Sensitive Hashing (LSH). In contrast to [AINR14], the new bound is not only optimal, but in fact improves over the best (optimal) LSH data structures [IM98,AI06] for all approximation factors $c>1$. From the technical perspective, we proceed by decomposing an arbitrary dataset into several subsets that are, in a certain sense, pseudo-random.Comment: 36 pages, 5 figures, an extended abstract appeared in the proceedings of the 47th ACM Symposium on Theory of Computing (STOC 2015