A Family of Iterative Gauss-Newton Shooting Methods for Nonlinear Optimal Control

This paper introduces a family of iterative algorithms for unconstrained nonlinear optimal control. We generalize the well-known iLQR algorithm to different multiple-shooting variants, combining advantages like straight-forward initialization and a closed-loop forward integration. All algorithms have similar computational complexity, i.e. linear complexity in the time horizon, and can be derived in the same computational framework. We compare the full-step variants of our algorithms and present several simulation examples, including a high-dimensional underactuated robot subject to contact switches. Simulation results show that our multiple-shooting algorithms can achieve faster convergence, better local contraction rates and much shorter runtimes than classical iLQR, which makes them a superior choice for nonlinear model predictive control applications.Comment: 8 page

Fatal Gaps: How Missing Records in the Federal Background Check System Put Guns in the Hands of Killers

This report analyzes newly released FBI data showing millions of records identifying seriously mentally ill people and drug abusers are missing from the NICS database because of lax state reporting. The data also show that 52 of 61 federal agencies that are required to submit records have not done so. The 50-state analysis identifies which states are best and worst at reporting, and examines the strategies that have helped some states succeed

Policing and Middle School: An Evaluation of a Statewide School Resource Officer Policy

This study investigates the effectiveness of North Carolina Senate Bill 402, Section 8.36 – Grants for School Resource Officers in Elementary and Middle Schools, which provides matching state funds to districts for use in middle and elementary schools. Using generalized difference-in-difference and negative binomial hurdle regression designs, seven years of data—inclusive of 110 districts and 471 middle schools—were analyzed to assess the effectiveness of the state-funded SRO program. Results show that offering matched SRO funds to increase policing and training was not associated with reductions in reported acts (infractions) per school year, a key measure of school safety. Racial enrollment percentages, such as higher enrollments of Black and Hispanic students, were generally not associated with increased disciplinary acts. However, total enrollment was associated with increases in reported acts and increased grade level proficiency was associated with reductions in reported acts. Findings also show that public policy activity generally increases after school shootings occur. However, a multi-pronged approach to school safety, beyond preventing mass acts of violence through increased policing, is recommended. Specifically, policies that focus on a broad range of issues, including those that improve academic achievement and address larger societal challenges have potential to enhance school safety

The Role of EU Integration in Accelerating Structural Reforms in the Western Balkans: Evidence, Theory and Policy. LEQS Paper No. 140/2019 January 2019

Integration with the European Union has been an important driver of economic, political and social transformation in the Western Balkans. In recent years, however, the pace of structural reforms in the region has decelerated and the trend of economic catch-up seen in the 2000s has not resumed after the slowdown of the global economic crisis. This has coincided – at least temporally, if not causally – with a ‘temporary freeze’ in the EU’s enlargement towards the region. Against this backdrop, this paper seeks to investigate the role of EU conditionality on economic reforms and convergence in the Western Balkans. To do so, it provides original, albeit descriptive, empirical evidence showing a strong link between EU-related structural reforms (towards the Copenhagen Criteria) and economic growth; and subsequently presents an analytical model demonstrating the mechanisms of policy decisions for reforms under EU conditionality. The model assumes away sectoral interests, policy uncertainty and coordination problems, allowing the analysis to focus specifically on the tension between two objectives: the pursuit of EU accession, through the implementation of jointly agreed reforms, and the accommodation of domestic policy concerns (maintaining policy stability and public support). Our results unveil a policy dilemma for the EU, having to choose between maximising the reform effort and minimising non-compliance. Drawing on this model, we discuss extensively the policy options that the EU faces in trying to enhance the reform performance, growth trajectories and, ultimately, European perspective of the countries in the region

Private-Sector Credit in Central & Eastern Europe: New (Over) Shooting Stars?

This paper analyzes the equilibrium level of private credit to GDP in 11 Central and Eastern European countries in order to see whether the high credit growth recently observed in some of these countries led to above equilibrium private credit to- GDP levels. We use estimation results obtained for a panel of small open OECD economies (out-of-sample sample) to derive the equilibrium credit level for a panel of transition economies (in-sample panel). We opt for this (out-of-sample) approach because the coefficient estimates for transition economies are fairly unstable. We show that there is a large amount of uncertainty to determine the equilibrium level of private credit. Yet our results indicate that a number of countries are very close or even above the estimated equilibrium levels, whereas others are still well below the equilibrium level.http://deepblue.lib.umich.edu/bitstream/2027.42/57232/1/wp852 .pd

Numerical optimal control for HIV prevention with dynamic budget allocation

This paper is about numerical control of HIV propagation. The contribution of the paper is threefold: first, a novel model of HIV propagation is proposed; second, the methods from numerical optimal control are successfully applied to the developed model to compute optimal control profiles; finally, the computed results are applied to the real problem yielding important and practically relevant results.Comment: Submitted pape

Women Under the Gun: How Gun Violence Affects Women and 4 Policy Solutions to Better Protect Them

Every day in the United States, five women are murdered with guns. Many of these fatal shootings occur in the context of a domestic or intimate partner relationship. However, women are not the only victims. Shooters have often made children, police officers, and their broader communities additional targets of what begins as an intimate partner shooting. In fact, one study found that more than half of the mass shootings in recent years have started with or involved the shooting of an intimate partner or a family member. Enacting a comprehensive set of laws and enforcement strategies to disarm domestic abusers and stalkers will reduce the number of women who are murdered by abusers with guns -- and it will make all Americans safer