Motion Planning Among Dynamic, Decision-Making Agents with Deep Reinforcement Learning

Robots that navigate among pedestrians use collision avoidance algorithms to enable safe and efficient operation. Recent works present deep reinforcement learning as a framework to model the complex interactions and cooperation. However, they are implemented using key assumptions about other agents' behavior that deviate from reality as the number of agents in the environment increases. This work extends our previous approach to develop an algorithm that learns collision avoidance among a variety of types of dynamic agents without assuming they follow any particular behavior rules. This work also introduces a strategy using LSTM that enables the algorithm to use observations of an arbitrary number of other agents, instead of previous methods that have a fixed observation size. The proposed algorithm outperforms our previous approach in simulation as the number of agents increases, and the algorithm is demonstrated on a fully autonomous robotic vehicle traveling at human walking speed, without the use of a 3D Lidar

Civic Contributions: Taxes Paid by Immigrants in the Washington, DC, Metropolitan Area

This report estimates the taxes paid by immigrants in the Washington, D.C., area in 1999-2000 and documents their demographics, household composition, income, and dispersal across jurisdictions in the region. The findings in this report are based mostly on analysis of 2000 U.S. Census data, because the census provides the most recent comprehensive data that allow disaggregation by country of origin groups and by many of the region's local jurisdictions. The demographic data in the report are updated through 2004 using the U.S. Current Population Survey. We calculate taxes at both the individual level (e.g., income and payroll taxes) and the household level (e.g., property taxes), but aggregate them up to the household level. Throughout the report we refer to households headed by immigrants (whether citizens, legal immigrants, or unauthorized migrants) as "immigrant households" and compare their incomes and tax payments to households headed by native-born U.S. citizens

Group Differences in Safety Climate Among Workers in the Nuclear Decommissioning and Demolition Industry in the United States

This study investigated group differences in safety climate among workers in the nuclear decommissioning and demolition (D&D) industry in the United States. The study population representative of workers in a high reliability industry included employees and subcontractors who worked at one of 10 locations in the United States managed by a multi-national corporation performing nuclear D&D operations. Safety climate was measured with a self-reported questionnaire, the Health and Safety Executive’s Health and Safety Climate Survey Tool (CST). The voluntary and anonymous responses totaled 1,587 out of an available population of 3,296 for an overall response rate of 48.1 percent. Significant differences (p\u3c0.001) were found by location, job position, on-the-job injuries and illnesses, and safety oriented behavior. Differences in self-reported safety climate among locations in high reliability industries were attributed to elements other than safety management systems. Differences in the self-reported safety climate among job positions in high reliability industries adduced evidence of two safety cultures in high reliability industries characterized by a negative relationship between hands-on work and safety climate. Differences in self-reported safety climate by self-reporting of on-the-job injuries or illness attested that worker safety attitudes and perceptions in high reliability industries degrade with the occurrence of on-the-job injuries and illnesses. Differences in self-reported safety climate by self-reported participation in safety oriented behavior bespoke the positive effect that participation in the safety program has on worker safety attitudes and perceptions. Recommended safety improvement strategies included 1) addressing the contributions of elements other than safety management systems such as social, political and human factors to the safety climate across locations; 2) attending to the self reported safety climate of the workers performing hands-on work; 3) implementing immediate and long term follow up with workers experiencing on-the-job injuries or illnesses; and 4) ensuring management support of worker participation in safety oriented behavior. Based on the study findings and conclusions, further research into group differences in safety climate in high reliability industries is recommended to better enable management teams to focus safety process improvements

The effect of diet on energy partitioning in moose

Thesis (Ph.D.) University of Alaska Fairbanks, 1987Moose (Alces alces) have dynamic seasonal patterns of food intake and body weight changes. Body weight may vary by 35% from winter lows to summer highs. Food intake levels during summer may exceed winter levels by up to a factor of 5. Forage quality and availability are thought to drive the seasonal patterns of food intake and weight loss. Changes in digestive strategy of moose in winter and spring were analyzed in this thesis. During December, the total mean retention time (TMRT) of food in the alimentary tract increased as dry matter intake decreased, while alimentary fill remained constant. In contrast, during April TMRT did not increase with increased intake; rather, alimentary fill increased. There appeared to be a seasonal digestive strategy for optimizing nutrient intake. True basal metabolic rate (TBM) was estimated using regression analysis of heat production on metabolizable energy intake. TBM was estimated at 68.8, close to the interspecies mean of 70 (kcal/kg BW\sp{0.75}/d). However, differences in TBM noted during December, February, and April were not significant. Paper birch (Betula papyrifera) twigs were collected during winter and cut from the tip to 8 specific diameters (2-9 mm), and analyzed for neutral detergent fiber, acid detergent fiber, crude protein, acid detergent lignin, ash, and in vitro dry matter disappearance. Results indicated that dietary quality decreased with increasing diameter. Moose subjected to 4 different stocking rates (23, 31, 41, and 66% utilization of paper birch) showed no difference in the diameter of paper birch (mean = 2.66 mm) harvested. A simulation model was presented in which food intake by moose was controlled by both physiological demands and alimentary capacity. Seasonal estimates of food intake changed with energy demands. The model proved useful in estimating seasonal energy requirements of moose

Socially Aware Motion Planning with Deep Reinforcement Learning

For robotic vehicles to navigate safely and efficiently in pedestrian-rich environments, it is important to model subtle human behaviors and navigation rules (e.g., passing on the right). However, while instinctive to humans, socially compliant navigation is still difficult to quantify due to the stochasticity in people's behaviors. Existing works are mostly focused on using feature-matching techniques to describe and imitate human paths, but often do not generalize well since the feature values can vary from person to person, and even run to run. This work notes that while it is challenging to directly specify the details of what to do (precise mechanisms of human navigation), it is straightforward to specify what not to do (violations of social norms). Specifically, using deep reinforcement learning, this work develops a time-efficient navigation policy that respects common social norms. The proposed method is shown to enable fully autonomous navigation of a robotic vehicle moving at human walking speed in an environment with many pedestrians.Comment: 8 page

The Use of Academic Regalia at a Land-Grant University: Faculty Attitudes and Beliefs

Each year academic regalia at US universities is a central component associated with the pomp and circumstance of commencement exercises. At one university, faculty of 20 different colleges play a significant role during those same commencement exercises. Currently, the Academic Costume Code, maintained by the American Council on Education, serves as the governing body for academic regalia at universities around the country. Though faculty play a prominent role in the visual presence at commencement exercises, little is known about faculty attitudes and beliefs regarding the use of academic regalia during commencement events. The goal of this research is to better understand the attitudes, beliefs, use, and opinions of current faculty at one Land-Grant university. The theory of planned behaviour provides the theoretical background for this research. This research study used an online instrument to census tenure-system, academic specialists, and fixed-term faculty at Michigan State University. Research objectives included: 1) defining how faculty use academic regalia in the context of commencement exercises; 2) determining the differences among attitudes, subjective norms, perceived behaviours, and opinions about the use of academic regalia; and 3) determining how faculty attitudes, subjective norms, and perceived behaviours determine intentions to use academic regalia in commencement exercises at a Land-Grant university. Results indicated that over 88 percent of faculty respondents positively supported the continued use of academic regalia at commencement events. Descriptive results also suggest a similar trend in attitudes and beliefs about the continued use of academic regalia at commencement exercises. A modified exploratory factor analysis (EFA) indicated observed constructs had a positive direct effect on factor loadings of attitudes and subjective norms, and behavioural control and intent. This research provides support for a continued understanding of attitudes and beliefs about the use of academic regalia; future studies should be conducted at other Land-Grant institutions in the United States

Nonisomorphic curves that become isomorphic over extensions of coprime degrees

We show that one can find two nonisomorphic curves over a field K that become isomorphic to one another over two finite extensions of K whose degrees over K are coprime to one another. More specifically, let K_0 be an arbitrary prime field and let r and s be integers greater than 1 that are coprime to one another. We show that one can find a finite extension K of K_0, a degree-r extension L of K, a degree-s extension M of K, and two curves C and D over K such that C and D become isomorphic to one another over L and over M, but not over any proper subextensions of L/K or M/K. We show that such C and D can never have genus 0, and that if K is finite, C and D can have genus 1 if and only if {r,s} = {2,3} and K is an odd-degree extension of F_3. On the other hand, when {r,s}={2,3} we show that genus-2 examples occur in every characteristic other than 3. Our detailed analysis of the case {r,s} = {2,3} shows that over every finite field K there exist nonisomorphic curves C and D that become isomorphic to one another over the quadratic and cubic extensions of K. Most of our proofs rely on Galois cohomology. Without using Galois cohomology, we show that two nonisomorphic genus-0 curves over an arbitrary field remain nonisomorphic over every odd-degree extension of the base field.Comment: LaTeX, 32 pages. Further references added to the discussion in Section 1

Curves of every genus with many points, II: Asymptotically good families

We resolve a 1983 question of Serre by constructing curves with many points of every genus over every finite field. More precisely, we show that for every prime power q there is a positive constant c_q with the following property: for every non-negative integer g, there is a genus-g curve over F_q with at least c_q * g rational points over F_q. Moreover, we show that there exists a positive constant d such that for every q we can choose c_q = d * (log q). We show also that there is a constant c > 0 such that for every q and every n > 0, and for every sufficiently large g, there is a genus-g curve over F_q that has at least c*g/n rational points and whose Jacobian contains a subgroup of rational points isomorphic to (Z/nZ)^r for some r > c*g/n.Comment: LaTeX, 18 page

‘Outdated and Anachronistic, but That’s Part of the Fun’: Faculty Attitudes and Beliefs Regarding Academic Dress at a Second Land-Grant University

This research sought to understand attitudes and behaviours of faculty at Kansas State University and used a previous research study, at Michigan State University, to validate the instrumentation developed while comparing and contrasting results between two Land-Grant institutions. Results of this study indicated consistent trends when comparing both of the Land-Grant universities about faculty attitude and behaviour. Due to the varied results between Kansas State and Michigan State in this study, the authors suggest further replication of the survey instrument at other Land-Grant institutions. This study builds on previous research suggesting that compelling evidence exists indicating that here are many individuals interested in the continued use of academic dress at Land-Grant universities