Former Insiders' Trading

Using detailed and unique data from Sweden, I show that former insiders trade profitably in the shares of companies with which they used to be affiliated. A trading strategy mimicking former insiders’ trading behavior yields abnormal returns of 7.6% per year. These returns are primarily driven by post-separation purchases rather than by sales. They do not reflect general stock-picking skills: former insiders earn significantly lower abnormal returns when trading in companies with which they have no affiliation. I show that former insiders’ informational advantage diminishes over time, but less so if they have ties to current insiders. The importance of such ties increases in the presence of value-relevant information. My results are consistent with former insiders benefiting from both a retained informational advantage and from inside information obtained post-separation when trading in inside stock

Are boys discriminated in Swedish high schools?

Girls typically have higher grades than boys in school and recent research suggests that part of this gender difference may be due to discrimination of boys. We rigorously test this in a field experiment where a random sample of the same tests in the Swedish language is subject to blind and non-blind grading. The non-blind test score is on average 15 % lower for boys than for girls. Blind grading lowers the average grades with 13 %, indicating that personal ties and/or grade inflation are important in non-blind grading. But we find no evidence of discrimination against boys. The point estimate of the discrimination effect is close to zero with a 95 % confidence interval of ±4.5 % of the average non-blind grade.Discrimination; Field experiments; Grading; Education; Gender

Ethnic Discrimination in High School Grading: Evidence from a Field Experiment

We rigorously test for ethnic discrimination in high school grading in Sweden. A random sample of the national tests in the Swedish language is graded both non-blind by the student’s own teacher and blind without any identifying information. The increase in the test score due to non-blind grading is significantly higher for students with Swedish background compared to students with foreign background. This discrimination effect is sizeable, and explains the entire difference in test scores between students with Swedish and foreign background.Discrimination; Field experiments; Education

Further results on binary convolutional codes with an optimum distance profile

Fixed binary convolutional codes are considered which are simultaneously optimal or near-optimal according to three criteria: namely, distance profiled, free distanced_{ infty}, and minimum number of weightd_{infty}paths. It is shown how the optimum distance profile criterion can be used to limit the search for codes with a large value ofd_{infty}. We present extensive lists of such robustly optimal codes containing rateR = l/2nonsystematic codes, several withd_{infty}superior to that of any previously known code of the same rate and memory; rateR = 2/3systematic codes; and rateR = 2/3nonsystematic codes. As a counterpart to quick-look-in (QLI) codes which are not "transparent," we introduce rateR = 1/2easy-look-in-transparent (ELIT) codes with a feedforward inverse(1 + D,D). In general, ELIT codes haved_{infty}superior to that of QLI codes

The cost of lying

We experimentally investigate the effect of cheap talk in a bargaining game with one-sided asymmetric information. A seller has private information about his or her skill and is provided an opportunity to communicate this information to a buyer through a written message. Four different treatments are compared; one without communication, one with free-form communication, and two treatments with pre-specified communication in the form of promises of varying strength. Our results suggest that lying about private information is costly and that the cost of lying increases with the size of the lie and the strength of the promise. Freely formulated messages lead to the fewest lies and the most efficient outcomes.Deception; Communication; Lies; Promises; Experiments

Integrated Stereovision for an Autonomous Ground Vehicle Competing in the Darpa Grand Challenge

The DARPA Grand Challenge (DGC) 2005 was a competition, in form of a desert race for autonomous ground vehicles, arranged by the U.S. Defense Advanced Research Project Agency (DARPA). The purpose was to encourage research and development of related technology. The objective of the race was to track a distance of 131.6 miles in less than 10 hours without any human interaction. Only public GPS signals and terrain sensors were allowed for navigation and obstacle detection. One of the teams competing in the DGC was Team Caltech from California Institute of Technology, consisting primarily of undergraduate students. The vehicle representing Team Caltech was a 2005 Ford E-350 van, named Alice. Alice had been modified for off-road driving and equipped with multiple sensors, computers and actuators. One type of terrain sensors used on Alice was stereovision. Two camera pairs were used for short and long range obstacle detection. This master thesis concerns development, testing and integration of stereovision sensors during the final four months leading to the race. To begin with, the stereovision system on Alice was not ready to use and had not undergone any testing. The work described in this thesis enabled operation of stereovision. It further improved its capability such that it increased the overall performance of Alice. Reliability was demonstrated through multiple desert field tests. Obstacle avoidance and navigation using only stereovision was successfully demonstrated. The completed work includes design and implementation of algorithms to improve camera focus and exposure control, increase processing speed and remove noise. Also hardware and software parameters were configured to achieve best possible operation. Alice managed to qualify to the race as one of the top ten vehicles. However she was only able to complete about 8 miles before running over a concrete barrier and out of the course, as a result of hardware failures and state estimation errors