Never carrying change. Needing only one identification card. Downloading concert tickets. Providing access to buildings. Tracking frequent flyer programs. Smart cards are the technology that allows each of these functions to occur. Although the technology evolved in the 1980s, it was only used for simple functions like pay phones. In the last decade, there has been a rapid increase in the use a...

In some urban transit systems, passengers are legally required to purchase tickets before entering but are not physically forced to do so. Instead, patrol units move about through the transit system, inspecting tickets of passengers, who face fines for fare evasion. This setting yields the problem of computing optimal patrol strategies satisfying certain temporal and spacial constraints, to det...

Complementing existing work on firm organizational structure and productivity, this paper examines the impact of organizational change on workers. We find evidence that employers do appear to compensate at least some of their workers for engaging in high performance workplace practices. We also find a significant association between high performance workplace practices and increased wage inequa...

Since the start of the recession in December 2007, the U.S. unemployment rate has risen more than four percentage points. Similar sharp increases in unemployment have occurred in other severe recessions, such as those in 1973-75 and 1981-82. In the aftermath of those severe recessions, the economy rapidly recovered and unemployment quickly declined. Will unemployment behave similarly following ...

potato image segmentation is an important part of image-based potato defect detection. this paper presents a robust potato color image segmentation through a combination of a fuzzy rule based system, an image thresholding based on genetic algorithm (ga) optimization and morphological operators. the proposed potato color image segmentation is robust against variation of background, distance and ...