Expectations Traps and Coordination Failures with Discretionary Policymaking

Discretionary policymakers cannot manage private-sector expectations and cannot coordinate the actions of future policymakers. As a consequence, expectations traps and coordination failures can occur and multiple equilibria can arise. To utilize the explanatory power of models with multiple equilibria it is first necessary to understand how an economy arrives to a particular equilibrium. In this paper we employ notions of learnability and self-enforceability to motivate and identify equilibria of particular interest. Central among these criteria are whether the equilibrium is learnable by private agents and jointly learnable by private agents and the policymaker. We use two New Keynesian policy models to identify the strategic interactions that give rise to multiple equilibria and to illustrate our methods for identifying equilibria of interest. Importantly, unless the Pareto-preferred equilibrium is learnable by private agents, we find little reason to expect coordination on that equilibrium.

Monetary Policy Delegation and Equilibrium Coordination

This paper revisits the argument that the stabilisation bias that arises under discretionary monetary policy can be reduced if policy is delegated to a policymaker with redesigned objectives. We study four delegation schemes: price level targeting, interest rate smoothing, speed limits and straight conservatism. These can all increase social welfare in models with a unique discretionary equilibrium. We investigate how these schemes perform in a model with capital accumulation where uniqueness does not necessarily apply. We discuss how multiplicity arises and demonstrate that no delegation scheme is able to eliminate all potential bad equilibria. Price level targeting has two interesting features. It can create a new equilibrium that is welfare dominated, but it can also alter equilibrium stability properties and make coordination on the best equilibrium more likely.

Coordination in Public Good Provision: How Individual Volunteering is Impacted by the Volunteering of Others

In this analysis, we examine the relationship between an individual's decision to volunteer and the average level of volunteering in the community where the individual resides. Our theoretical model is based on a coordination game , in which volunteering by others is informative regarding the benefit from volunteering. We demonstrate that the interaction between this information and one's private information makes it more likely that he or she will volunteer, given a higher level of contributions by his or her peers. We complement this theoretical work with an empirical analysis using Census 2000 Summary File 3 and Current Population Survey (CPS) 2004-2007 September supplement file data. We control for various individual and community characteristics, and employ robustness checks to verify the results of the baseline analysis. We additionally use an innovative instrumental variables strategy to account for reflection bias and endogeneity caused by selective sorting by individuals into neighborhoods, which allows us to argue for a causal interpretation. The empirical results in the baseline, as well as all robustness analyses, verify the main result of our theoretical model, and we employ a more general structure to further strengthen our results.

Coordination in Public Good Provision: How Individual Volunteering is Impacted by the Volunteering of Others

In this analysis, we examine the relationship between an individual’s decision to volunteer and the average level of volunteering in the community where the individual resides. Our theoretical model is based on a coordination game , in which volunteering by others is informative regarding the benefit from volunteering. We demonstrate that the interaction between this information and one’s private information makes it more likely that he or she will volunteer, given a higher level of contributions by his or her peers. We complement this theoretical work with an empirical analysis using Census 2000 Summary File 3 and Current Population Survey (CPS) 2004-2007 September supplement file data. We control for various individual and community characteristics, and employ robustness checks to verify the results of the baseline analysis. We additionally use an innovative instrumental variables strategy to account for reflection bias and endogeneity caused by selective sorting by individuals into neighbourhoods, which allows us to argue for a causal interpretation. The empirical results in the baseline, as well as all robustness analyses, verify the main result of our theoretical model, and we employ a more general structure to further strengthen our results.

ETIKETAGGER: herramienta para el etiquetaje de secuencias de imágenes

La adaptación del reconocimiento de objetos sobre la robótica móvil requiere un enfoque y nuevas aplicaciones que optimicen el entrenamiento de los robots para obtener resultados satisfactorios. Es conocido que el proceso de entrenamiento es largo y tedioso, donde la intervención humana es absolutamente necesaria para supervisar el comportamiento del robot y la dirección hacia los objetivos. Es por esta razón que se ha desarrollado una herramienta que reduce notablemente el esfuerzo humano que se debe hacer para esta supervisión, automatizando el proceso necesario para obtener una evaluación de resultados, y minimizando el tiempo que se malgasta debido a errores humanos o falta de infraestructuras.

Estudi de comportaments socials amb eixams de robots reconfigurables

Els eixams de robots distribuïts representen tot un món de possibilitats al camp de la microrobòtica, però existeixen pocs estudis que n'analitzin els comportaments socials i les interaccions entre robots autònoms distribuïts. Aquests comportaments han de permetre assolir de la manera més efectiva possible un bon resultat. Prenent com a base l'objectiu esmentat, aquest treball detalla diferents polítiques de cerca i de reconfiguració dels robots i estudia els seus comportaments per tal de determinar quins d'ells són més útils per solucionar un problema concret amb les plagues d'erugues i corcs als camps de cigroneres.

Robotic, fluoroscopic or EMG assisted pedicle screw insertion. A CT based comparative study

Introduction: In order to improve safety of pedicle screw placement several techniques have been developed. More recently robotically assisted pedicle insertion has been introduced aiming at increasing accuracy. The aim of this study was to compare this new technique with the two main pedicle insertion techniques in our unit namely fluoroscopically assisted vs EMG aided insertion. Material and methods: A total of 382 screws (78 thoracic,304 lumbar) were introduced in 64 patients (m/f = 1.37, equally distributed between insertion technique groups) by a single experienced spinal surgeon. From those, 64 (10 thoracic, 54 lumbar) were introduced in 11 patients using a miniature robotic device based on pre operative CT images under fluoroscopic control. 142 (4 thoracic, 138 lumbar) screws were introduced using lateral fluoroscopy in 27 patients while 176 (64 thoracic, 112 lumbar) screws in 26 patients were inserted using both fluoroscopy and EMG monitoring. There was no difference in the distribution of scoliotic spines between the 3 groups (n = 13). Screw position was assessed by an independent observer on CTs in axial, sagittal and coronal planes using the Rampersaud A to D classification. Data of lumbar and thoracic screws were processed separately as well as data obtained from axial, sagittal and coronal CT planes. Results: Intra- and interobserver reliability of the Rampersaud classification was moderate, (0.35 and 0.45 respectively) being the least good on axial plane. The total number of misplaced screws (C&D grades) was generally low (12 thoracic and 12 lumbar screws). Misplacement rates were same in straight and scoliotic spines. The only difference in misplacement rates was observed on axial and coronal images in the EMG assisted thoracic screw group with a higher proportion of C or D grades (p <0.05) in that group. Recorded compound muscle action potentials (CMAP) values of the inserted screws were 30.4 mA for the robot and 24.9mA for the freehand technique with a CI of 3.8 of the mean difference of 5.5 mA. Discussion: Robotic placement did improve the placement of thoracic screws but not that of lumbar screws possibly because our misplacement rates in general near that of published navigation series. Robotically assisted spine surgery might therefore enhance the safety of screw placement in particular in training settings were different users at various stages of their learning curve are involved in pedicle instrumentation.

Análisis de prestaciones de sistemas de comunicaciones inalámbricas en aplicaciones de robótica: sistema software

Una característica importante de la robótica es la comunicación entre sistema base y robot que puede establecerse de forma remota. Ello representa la base del proyecto que se describe a continuación, el cual se descompone de dos partes, una por cada miembro del proyecto: sistema software y sistema hardware. En el sistema software analizaremos las diferentes tecnologías inalámbricas (características, funcionamiento, seguridad, etc.), se realizará una comparativa de los diferentes módulos de comunicación y finalmente decidiremos aquellos que nos interesa para la implementación en Radiofrecuencia (RF) y Bluetooth. En este sistema también estudiaremos la interfaz gráfica que se utilizará, así como los programas creados en este entorno para realizar las implementaciones. En el sistema hardware trataremos de realizar el control de dos periféricos de forma independiente, un servomotor y un sonar, que nos servirán como ejemplo para analizar una posible comunicación entre varios robots y un PC. Por lo tanto, en este apartado analizaremos a fondo los diferentes componentes que harán posible tanto la comunicación, vía RF y Bluetooth, como el control de los diferentes dispositivos.

Análisis de prestaciones de sistemas de comunicaciones inalámbricas en aplicaciones de robótica: sistema hardware

Una característica importante de la robótica es la comunicación entre sistema base y robot que puede establecerse de forma remota. Ello representa la base del proyecto que se describe a continuación, el cual se descompone de dos partes, una por cada miembro del proyecto: Sistema software y sistema hardware. En el sistema software analizaremos las diferentes tecnologías inalámbricas (características, funcionamiento, seguridad, etc.), se realizará una comparativa de los diferentes módulos de comunicación y finalmente decidiremos aquellos que nos interesa para la implementación en Radiofrecuencia (RF) y Bluetooth. En este sistema también estudiaremos la interfaz gráfica que se utilizará, así como los programas creados en este entorno para realizar las implementaciones. En el sistema hardware trataremos de realizar el control de dos periféricos de forma independiente, un servomotor y un sonar, que nos servirán como ejemplo para analizar una posible comunicación entre varios robots y un PC. Por lo tanto, en este apartado analizaremos a fondo los diferentes componentes que harán posible tanto la comunicación, vía RF y Bluetooth, como el control de los diferentes dispositivos.