A Note on Flips in Diagonal Rectangulations

Rectangulations are partitions of a square into axis-aligned rectangles. A number of results provide bijections between combinatorial equivalence classes of rectangulations and families of pattern-avoiding permutations. Other results deal with local changes involving a single edge of a rectangulation, referred to as flips, edge rotations, or edge pivoting. Such operations induce a graph on equivalence classes of rectangulations, related to so-called flip graphs on triangulations and other families of geometric partitions. In this note, we consider a family of flip operations on the equivalence classes of diagonal rectangulations, and their interpretation as transpositions in the associated Baxter permutations, avoiding the vincular patterns { 3{14}2, 2{41}3 }. This complements results from Law and Reading (JCTA, 2012) and provides a complete characterization of flip operations on diagonal rectangulations, in both geometric and combinatorial terms

A new meta-module for efficient reconfiguration of hinged-units modular robots

We present a robust and compact meta-module for edge-hinged modular robot units such as M-TRAN, SuperBot, SMORES, UBot, PolyBot and CKBot, as well as for central-point-hinged ones such as Molecubes and Roombots. Thanks to the rotational degrees of freedom of these units, the novel meta-module is able to expand and contract, as to double/halve its length in each dimension. Moreover, for a large class of edge-hinged robots the proposed meta-module also performs the scrunch/relax and transfer operations required by any tunneling-based reconfiguration strategy, such as those designed for Crystalline and Telecube robots. These results make it possible to apply efficient geometric reconfiguration algorithms to this type of robots. We prove the size of this new meta-module to be optimal. Its robustness and performance substantially improve over previous results.Peer ReviewedPostprint (author's final draft

Extracting quasi-steady Lagrangian transport patterns from the ocean circulation: An application to the Gulf of Mexico

We construct a climatology of Lagrangian coherent structures (LCSs), the concealed skeleton that shapes transport, with a twelve-year-long data-assimilative simulation of the sea-surface circulation in the Gulf of Mexico (GoM). Computed as time-mean Cauchy-Green strain tensorlines of the climatological velocity, the climatological LCSs (cLCSs) unveil recurrent Lagrangian circulation patterns. cLCSs strongly constrain the ensemble-mean Lagrangian circulation of the instantaneous model velocity, thus we show that a climatological velocity may preserve meaningful transport information. Also, the climatological transport patterns we report agree well with GoM kinematics and dynamics, as described in several previous observational and numerical studies. For example, cLCSs identify regions of persistent isolation, and suggest that coastal regions previously identified as high-risk for pollution impact, are regions of maximal attraction. Also, we show examples where cLCSs are remarkably similar to transport patterns observed during the Deepwater Horizon and Ixtoc oil spills, and during the Grand LAgrangian Deployment (GLAD) experiment. Thus, it is shown that cLCSs are an efficient way of synthesizing vast amounts of Lagrangian information. The cLCS method confirms previous GoM studies, and contributes to our understanding by revealing the persistent nature of the dynamics and kinematics treated therein.Comment: To be submitte

El vidrio y su poética en la arquitectura moderna en Chile

Ponència presentada a: Session 5: Del diseño a la construcción. Sostenibilidad (temas de diseño ambiental) / From design to construction. Sustainability (environmental design issues

Indicio, detalle y objeto: propuesta metodológica para el estudio de la transferencia de la arquitectura moderna a Chile

Ponència presentada a: Session 5: Del diseño a la construcción: Sostenibilidad (temas de diseño ambiental) / From design to construction: Sustantibility (enviromental design issues

Party ideology and policies where corruption is widespread: evidence from local governments

This dissertation studies the effect of mayors aligned with a centre left presidential coalition on policy outcomes and corruption. I use Regression Discontinuity Design in Brazilian municipal elections for two mayoral terms, from 2001 to 2008. Theories about politician´s behaviour, include ideological and self-interested motivations, although previous studies analyse it separately. Results indicate that municipalities aligned with the president’s coalition receives more transfers but are not more corrupt and allocate resources differently. Therefore, even in the context of institutional fragility and corruption, politician’s preferences about policies can be relevant in the provision of public services.Agencia Nacional de Investigación e Innovació

Party ideology and policies where corruption is widespread: evidence from local governments

This dissertation studies the effect of mayors aligned with a centre left presidential coalition on policy outcomes and corruption. I use Regression Discontinuity Design in Brazilian municipal elections for two mayoral terms, from 2001 to 2008. Theories about politician´s behaviour, include ideological and self-interested motivations, although previous studies analyse it separately. Results indicate that municipalities aligned with the president’s coalition receives more transfers but are not more corrupt and allocate resources differently. Therefore, even in the context of institutional fragility and corruption, politician’s preferences about policies can be relevant in the provision of public services.Agencia Nacional de Investigación e Innovació

El rol del tiempo en un proceso de modelación utilizando vídeos de experimentos físicos

En este trabajo se investiga el rol que cumple el tiempo en un proceso de modelación que busca favorecer la construcción de conocimiento matemático en alumnos universitarios. En ese proceso se evidencia la funcionalidad de las gráficas para describir un fenómeno físico, usando la tecnología track moving objects. La investigación utiliza una perspectiva socioepistemológica para analizar las prácticas de modelación-graficación de alumnos de primer año de la carrera de Matemáticas de una universidad chilena enfrentados al estudio del movimiento de proyectiles

Symbolism and mysticism of the Sea Wolf in the former northern coast of Peru

El objetivo de este trabajo es realizar el modelamiento y calcular la fuerza total, tangencial, radial y axial, porque, velocidad angular de desplazamiento lateral, rigidez del resorte lineal y del amortiguador viscoso en el dominio del tiempo debido a las vibraciones generadas en el sistema de transmisión de un aerogenerador de inducción doblemente alimentado con velocidad fija por la acción de las cargas mecánicas. Para realizar el modelamiento y simulación se utilizará un modelo multi masa del sistema de transmisión, donde cada componente tendrá un grado de libertad y las fuerzas de contacto se modelan con un resorte lineal y su respectiva rigidez. Además, el modelo de masa única no es lo suficiente preciso para un análisis vibracional de esta magnitud.Abstract : The objective of this work is modeling and calculating the total, tangential, radial and axial force, torque, lateral displacement angular velocity, linear spring stiffness and viscous damping in the time domain due to vibrations in the system transmission of a wind turbine doubly fed induction with fixed speed by the action of mechanical loads. To perform the modeling and simulation, a multi mass model of the transmission system will be use, where each component will have a degree of freedom and the contact forces are modeled with a linear spring and its respective rigidity. In addition, the single mass model is not sufficiently accurate for a vibrational analysis of this magnitude