A dual output polarimeter devoted to the study of the Cosmic Microwave Background

We have developed a correlation radiometer at 33 GHz devoted to the search for residual polarization of the Cosmic Microwave Background (CMB). The two instruments`s outputs are linear combination of two Stokes Parameters (Q and U or U and V). The instrument is therefore directly sensitive to the polarized component of the radiation (respectively linear and circular). The radiometer has a beam-width oif 7 or 14 deg, but it can be coupled to a telescope increasing the resolution. The expected CMB polarization is at most a part per milion. The polarimeter has been designed to be sensitive to this faint signal, and it has been optimized to improve its long term stability, observing from the ground. In this contribution the performances of the instrument are presented, together with the preliminary test and observations.Comment: 12 pages, 6 figures, in print on the Proc. SPIE Conf. - August 200

Urban commoning in a civic social network: the case study of FirstLife

The integration of ICTs in the urban management is increasing at all levels of public administrations in order to improve efficiency and effectiveness of public services, but their role is still instrumental rather than drive a change toward a more collaborative local governance. On the other hand, there is a raising expectation of the civil society to participate in decision making processes and contribute in defining local policies about sensitive topics. These purposes are often addressed by using or creating community digital tools designed for a specific contextual scope, resulting in a deep fragmentation of information about civic initiatives and social innovation projects and a lack of continuous communication among urban stakeholders even working in the same area. The challenge is to design an ICT solution to refactor the current practices of cooperation between private and public sector and support a real change in the city management processes from the local to the territorial level. In this contribution, we present the development of FirstLife, a map-based civic social network, designed to represent the complex environment of the city through geo-referenced time framed crowdsourced data about urban entities as events, places, groups, initiatives, projects, stories, news, etc. The main goals of the platform are to support the action of multiple stakeholders in alternative processes of co-management of common or shared resources, as for instance public spaces, green areas and buildings hosting collective institutions, to enable the co-production of services based on a reform of local administrative protocols toward the We-government model, and to empower mixed local networks. The development of FirstLife followed a participatory action design research methodology involving several stakeholders among associations, local authorities and institutions, businesses and the University in the city of Turin in the last two years. The participatory process started from the requirement elicitation, and continued with the collection of applicative scenarios based on the context analysis of internal/external relations of groups of stakeholders and the balancing of their goals in a common platform. Then, the co-design of features has been undertaken in the stakeholders’ working environments to model the platform functionalities on the real processes and practices defining social acceptable technological solutions, ready to be adopted by institutional and civic organizations. The platform has been tested-in-use in multiple living labs and pilot projects, experimenting a number of use patterns representing the common actions in the city carried out by public or private actors. These activities have been integrated in an iterative development cycle that brought so far at four progressively improved versions of FirstLife, from a map-based tool to share georeferenced information to a common workbench for multiple stakeholders acting in the same area (from the neighbourhood to the city level) where open groups can self-organize initiatives and cooperate with others. The result of this process is a digital space for urban commoning practices,reflecting the organization of society in individuals and structured public and private entities, the spatial framework of their actions and the temporal development of city transformations and initiatives

Timing, glitches and braking index of PSR B0540-69

We report a pulse-time history of PSR B0540$-$69 based on the analysis of an extended Data set including ASCA, BeppoSAX and RXTE observations spanning a time interval of about 8 years. This interval includes also the epoch of the glitch episode reported by Zhang et al. (2001). Our analysis shows the presence of a relevant timing noise and does not give a clear evidence of the glitch occurrence. We performed an accurate evaluation of the main timing parameters, $\nu$, $\dot{\nu}$ and $\ddot{\nu}$ and derived a mean braking index of $n=2.125\pm0.001$ quite different from the lower value found by Zhang et al. (2001), but in rather good agreement with other several values reported in the literature.Comment: 9 pages 5 figures, accepted by A&A, main journa

Neural-Symbolic Monitoring and Adaptation

Runtime monitors check the execution of a system under scrutiny against a set of formal specifications describing a prescribed behaviour. The two core properties for monitoring systems are scalability and adaptability. In this paper we show how RuleRunner, our previous neural-symbolic monitoring system, can exploit learning strategies in order to integrate desired deviations with the initial set of specification. The resulting system allows for fast conformance checking and can suggest possible enhanced models when the initial set of specifications has to be adapted in order to include new patterns

Timing and spectral changes of the Be X-ray transient EXO 0531-6609.2 through high and low state

We report on spectral and timing analysis of BeppoSAX data of the 13.6 s period transient X-ray pulsar EXO 0531-6609.2. Observations were carried out in March 1997 and October 1998, catching the source during a high and a low emission state, respectively. Correspondingly, the X-ray luminosity is found at a level of 4.2x10^37 erg/s and 1.5x10^36 erg/s in the two states. In the high state the X-ray emission in the energy range 1-100 keV is well fitted by an absorbed power-law with photon index Gamma ~1.7 plus a blackbody component with a characteristic temperature of ~3.5 keV. Moreover, we find an evidence of an iron emission at ~6.8 keV, typical feature in this class of sources but never revealed before in the EXO 0531-6609.2 spectrum. In the low state an absorbed power-law with Gamma ~0.4 is sufficient to fit the 1-10 keV data. During BeppoSAX observations EXO 0531-6609.2 display variations of the pulse profile with the X-ray flux: it showed single peaked and double peaked profiles in the low and high state, respectively. Based on these two observations we infer a spin-up period derivative of -(1.14+/-0.08)x10^-10 s/s. By comparing these with other period measurements reported in literature we find an alternating spin-up and spin-down behaviour that correlates well with the X-ray luminosity.Comment: 6 pages, 8 figures, A&