University of Sannio

About: University of Sannio is a education organization based out in Benevento, Italy. It is known for research contribution in the topics: Gravitational wave & LIGO. The organization has 1278 authors who have published 6125 publications receiving 167577 citations. The organization is also known as: Università degli Studi del Sannio & Universita degli Studi del Sannio.

The Evolution of Project Inter-dependencies in a Software Ecosystem: The Case of Apache

Abstract: Software ecosystems consist of multiple software projects, often interrelated each other by means of dependency relations. When one project undergoes changes, other projects may decide to upgrade the dependency. For example, a project could use a new version of another project because the latter has been enhanced or subject to some bug-fixing activities. This paper reports an exploratory study aimed at observing the evolution of the Java subset of the Apache ecosystem, consisting of 147 projects, for a period of 14 years, and resulting in 1,964 releases. Specifically, we analyze (i) how dependencies change over time, (ii) whether a dependency upgrade is due to different kinds of factors, such as different kinds of API changes or licensing issues, and (iii) how an upgrade impacts on a related project. Results of this study help to comprehend the phenomenon of library/component upgrade, and provides the basis for a new family of recommenders aimed at supporting developers in the complex (and risky) activity of managing library/component upgrade within their software projects.

First Searches for Optical Counterparts to Gravitational-wave Candidate Events

Abstract: During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type.

Quasi-dynamic estimation of o–d flows from traffic counts: Formulation, statistical validation and performance analysis on real data

Abstract: The paper proposes a “quasi-dynamic” framework for estimation of origin–destination (o–d) flow from traffic counts, under the assumption that o–d shares are constant across a reference period, whilst total flows leaving each origin vary for each sub-period within the reference period. The advantage of this approach over conventional within-day dynamic estimators is that of reducing drastically the number of unknowns given the same set of observed time-varying traffic counts. Obviously, the gain in accuracy depends on how realistic is the underlying assumption that total demand levels vary more rapidly over time than o–d shares. Firstly, the paper proposes a theoretical specification of the quasi-dynamic estimator. Subsequently, it proposes empirical and statistical tests to check the quasi-dynamic assumption and then compares the performances of the quasi-dynamic estimator of o–d flows with both classical off-line simultaneous dynamic estimators and on-line recursive Kalman filter-based estimators. Experiments are carried out on the real test site of A4–A23 motorways in North-Eastern Italy. Results confirm the acceptability of the assumption of quasi-dynamic o–d flows, even under the hypothesis of constant distribution shares for the whole day and show that the quasi-dynamic estimator outperforms significantly the simultaneous estimator. Data also suggest that using the quasi-dynamic estimates instead of the simultaneous estimates as historical o–d flows improves significantly the performances of the Kalman filter, which strongly depends of the quality of the seed o–d flows. In addition, it is shown that the aggregation of quasi-dynamic o–d estimates across subsequent time slices represents also the most effective way to obtain o–d estimates for larger time horizons (e.g. hourly estimates). Finally, a validation based on an hold-out sample of link flows (i.e. counts not used as inputs in the o–d estimation/updating process) revealed the quasi-dynamic estimator to be overall more robust and effective with respect to the other tested estimators.

Sex steroid hormone fluctuations and morphological changes of the reproductive system of the female of Octopus vulgaris throughout the annual cycle.

Abstract: Sex steroids (17beta-estradiol and progesterone) and morphological variations of the reproductive system of the female of Octopus vulgaris from the Bay of Naples were followed over a period of 2 years. The increase in the ovary weight was independent of body weight as demonstrated by the gonado-somatic index (GSI). Both 17beta-estradiol and progesterone have been detected in the ovary of O. vulgaris, and their concentrations changed in correlation with the ovarian development. No 17beta-estradiol or progesterone was found in the hemolymph. 3beta-Hydroxysteroid dehydrogenase activity has been detected in the ovary, indicating that in the female of O. vulgaris the reproductive system is a source of sex steroid hormones. According to the morphological changes of the ovary, the ovarian cycle can be divided into the following phases: previtellogenesis; early vitellogenesis, full vitellogenesis and late vitellogenesis. The morphological changes of the oviducts and oviducal glands throughout the reproductive cycle were in accordance with their role in the transport and secretion of gelatinous coat covering the eggs, as well as in sperm storage and sperm reactivation during fertilization. J. Exp. Zool. 289:33-47, 2001.