On the Observability of Giant Protoplanets in Circumstellar Disks

We investigate the possibility to detect giant planets that are still embedded in young circumstellar disks. Based on models with different stellar, planetary, and disk masses, and different radial positions of the planet we analyze the resulting submillimeter appearance of these systems. We find that the influence of the planet on the spectral energy distribution could not be distinguished from that of other disk parameters. However, dust reemission images of the disks show that the hot region in the proximity of a young planet, along with the gap, could indeed be detected and mapped with the Atacama Large Millimeter Array in the case of nearby circumstellar disks (d<100pc) in approximate face-on orientation.Comment: ApJ, in pres

Searching in Unstructured Overlays Using Local Knowledge and Gossip

This paper analyzes a class of dissemination algorithms for the discovery of distributed contents in Peer-to-Peer unstructured overlay networks. The algorithms are a mix of protocols employing local knowledge of peers' neighborhood and gossip. By tuning the gossip probability and the depth k of the k-neighborhood of which nodes have information, we obtain different dissemination protocols employed in literature over unstructured P2P overlays. The provided analysis and simulation results confirm that, when properly configured, these schemes represent a viable approach to build effective P2P resource discovery in large-scale, dynamic distributed systems.Comment: A revised version of the paper appears in Proc. of the 5th International Workshop on Complex Networks (CompleNet 2014) - Studies in Computational Intelligence Series, Springer-Verlag, Bologna (Italy), March 201

Gathering an even number of robots in an odd ring without global multiplicity detection

We propose a gathering protocol for an even number of robots in a ring-shaped network that allows symmetric but not periodic configurations as initial configurations, yet uses only local weak multiplicity detection. Robots are assumed to be anonymous and oblivious, and the execution model is the non- atomic CORDA model with asynchronous fair scheduling. In our scheme, the number of robots k must be greater than 8, the number of nodes n on a network must be odd and greater than k+3. The running time of our protocol is O(n2) asynchronous rounds.Comment: arXiv admin note: text overlap with arXiv:1104.566

Hydromagnetic and gravitomagnetic crust-core coupling in a precessing neutron star

We consider two types of mechanical coupling between the crust and the core of a precessing neutron star. First, we find that a hydromagnetic (MHD) coupling between the crust and the core strongly modifies the star's precessional modes when $t_a\le\sim (T_s\times T_p)^{1/2}$; here $t_a$ is the Alfven crossing timescale, and $T_s$ and $T_p$ are the star's spin and precession periods, respectively. We argue that in a precessing pulsar PSR B1828-11 the restoring MHD stress prevents a free wobble of the crust relative to the non-precessing core. Instead, the crust and the proton-electron plasma in the core must precess in unison, and their combined ellipticity determines the period of precession. Link has recently shown that the neutron superfluid vortices in the core of PSR B1828-11 cannot be pinned to the plasma; he has also argued that this lack of pinning is expected if the proton Fermi liquid in the core is type-I superconductor. In this case, the neutron superfluid is dynamically decoupled from the precessing motion. The pulsar's precession decays due to the mutual friction between the neutron superfluid and the plasma in the core. The decay is expected to occur over tens to hundreds of precession periods and may be measurable over a human lifetime. Such a measurement would provide information about the strong n-p interaction in the neutron-star core. Second, we consider the effect of gravitomagnetic coupling between the neutron superfluid in the core and the rest of the star and show that this coupling changes the rate of precession by about 10%. The general formalism developed in this paper may be useful for other applications.Comment: 6 page

A stability with optimality analysis of consensus-based distributed filters for discrete-time linear systems

In this paper we investigate how stability and optimality of consensus-based distributed filters depend on the number of consensus steps in a discrete-time setting for both directed and undirected graphs. By introducing two new algorithms, a simpler one based on dynamic averaging of the estimates and a more complex version where local error covariance matrices are exchanged as well, we are able to derive a complete theoretical analysis. In particular we show that dynamic averaging alone suffices to approximate the optimal centralized estimate if the number of consensus steps is large enough and that the number of consensus steps needed for stability can be computed in a distributed way. These results shed light on the advantages as well as the fundamental limitations shared by all the existing proposals for this class of algorithms in the basic case of linear time-invariant systems, that are relevant for the analysis of more complex situations

Design and Development of the Engine Unit for a Twin-Rotor Unmanned Aerial Vehicle

Advanced computer-aided technologies played a crucial role in the design of an unconventional Uninhabited Aerial Vehicle (UAV), developed at the Turin Technical University and the University of Rome “La Sapienza”. The engine unit of the vehicle is made of a complex system of three two stroke piston engines coupled with two counter-rotating three-bladed rotors, controlled by rotary PWM servos. The focus of the present paper lies on the enabling technologies exploited in the framework of activities aimed at designing a suitable and reliable engine system, capable of performing the complex tasks required for operating the proposed rotorcraft. The synergic use of advanced computational tools for estimating the aerodynamic performance of the vehicle, solid modeling for mechanical components design, and rapid prototyping techniques for control system logic synthesis and implementation will be presented.

Tomographic test of Bell's inequality for a time-delocalized single photon

Time-domain balanced homodyne detection is performed on two well-separated temporal modes sharing a single photon. The reconstructed density matrix of the two-mode system is used to prove and quantify its entangled nature, while the Wigner function is employed for an innovative tomographic test of Bell's inequality based on the theoretical proposal by Banaszek and Wodkiewicz [Phys. Rev. Lett. 82, 2009 (1999)]. Provided some auxiliary assumptions are made, a clear violation of Banaszek-Bell's inequality is found.Comment: 7 pages, 3 figures: revised version with additional material; accepetd for publication in Phys. Rev.

Seismic assessment and rehabilitation of a historical theatre based on a macro-element strategy

The structural and seismic assessment of the 19th-century Petruzzelli theater in Bari (Italy) is presented. The macro-elements strategy was adopted to dismantle the whole structure in parts. The steel dome was verified through dynamic multi-modal analysis based on finite element model. Each masonry macro-element was firstly verified through a kinematic analysis aiming at excluding local collapse mechanisms. Afterwards, a nonlinear static analysis was carried out in order to evaluate its overall seismic capacity. The effectiveness of linear or nonlinear analyses and of the macro-element strategy compared with other modeling techniques is also discussed. After highlighting the structural deficiencies of the theater, upgrading solutions are proposed with consideration of the safety needs and the architectural preservation requirements based on the historical importance of the buildin

Internationalisation, cultural distance and country characteristics: a Bayesian analysis of SME's financial performance

Relying on the accounting data of a panel of 403 Italian manufacturing SMEs collected over a period of 5 years, we find results suggesting that multinationality per se does not impact on the economic performance of international small and medium sized firms. It is the characteristics of the country selected i.e. the political hazard, the financial stability and the economic performance that significantly influence SMEs financial performance. The management implication for small and medium sized firms selecting and entering new geographic markets is significant, since our results show that for SMEs it is the market selection process that really matters and not the degree of multinationality

Con prisa y con pausas. Aproximaciones a la cuestión del financiamiento para la producción del hábitat popular en Campo Unamuno en la posconvertibilidad

Esta ponencia pretende reflexionar acerca de los procesos de producción del hábitat popular y de producción de ciudad que protagonizaron y protagonizan hogares del Conurbano Bonaerense durante la posconvertibilidad. Más específicamente, acerca de las estrategias de financiamiento para la producción del hábitat de hogares pertenecientes a tres barrios de Campo Unamuno, ubicado en el partido de Lomas de Zamora. El trabajo se inscribe en el marco de realización de una tesis de maestría en curso sobre esta temática. Aquí nos ocuparemos de sistematizar los modos en que estos hogares han financiado y financian la producción de su hábitat en la posconvertibilidad, en particular, en lo referido a la dimensión de acceso al suelo y a la vivienda y a su mejoramiento a lo largo del tiempo. Los datos utilizados como insumo fueron obtenidos a partir de un relevamiento de campo coordinado por el equipo de investigación que la autora integra y realizado durante los meses de junio y julio de 2015. A través de una muestra representativa se han relevado los barrios: 17 de Marzo, Soledad y Libre Amanecer y se ha utilizado una estrategia metodológica combinada, cuanti y cualitativa. Finalmente, el trabajo se inscribe en las líneas de investigación del equipo de la Undav arriba mencionado, el cual viene reelaborando un marco teórico de trabajo en el que están implicados conceptos como: sectores populares, economía popular, estrategias de reproducción social, estrategias de financiamiento, producción del hábitat, territorio.Mesa 29: “La cuestión urbana interrogada”: producción de la ciudad, actores y conflictos, una mirada desde los estudios urbanosFacultad de Humanidades y Ciencias de la Educació