1,721,047 research outputs found
Scienze dell'antichità. Storia, archeologia, antropologia. (2023). Vol. 29/3
No full textL'edizione del volume monografico della rivista Scienze dell'Antichita (29, 3, 2023) dedicato al terzo convegno Egitto e Vicino Oriente (EVOA) 2022 è a cura del professor Carlo G. Cereti, e dei dottori Angelica Gaspari, Carlo Marchetti e Massimiliano Vassall
Three-tier replication for FT-CORBA infrastructures
No full textEnforcing strong replica consistency among a set of replicas of a service deployed across an asynchronous distributed system in the presence of crash failures is a real practical challenge. If each replica runs the consistency protocol bundled with the actual service implementation, this target cannot be achieved, as replicas need to be located over a partially synchronous distributed system to solve the distributed agreement problems underlying strong replica consistency. A three-tier architecture for software replication enables the separation of the replication logic, i.e. protocols and mechanisms necessary for managing software replication, from both clients and server replicas. The replication logic is embedded in a middle-tier that confines the need of partial synchrony and thus frees replica deployment. In this paper we first introduce the basic concepts underlying three-tier replication. Then we present the interoperable replication logic (IRL) architecture, a fault-tolerant CORBA compliant infrastructure. IRL exploits a three-tier approach to replicate stateful deterministic CORBA objects and allows object replicas to run on object request brokers from different vendors. A description of an IRL prototype developed in our department is proposed along with an extensive performance analysis. Copyright (C) 2003 John Wiley Sons, Ltd
CORBA request portable interceptors: analysis and applications
No full textInterceptors are an emerging middleware technology enabling the addition of specific network-oriented capabilities to distributed applications. By exploiting interceptors, developers can register code within interception points, extending the basic middleware mechanisms with specific functionality, e.g. authentication, flow control, caching, etc. Notably, these extensions can be achieved without modifying either the application or the middleware code. In this paper we report the results of our experiences with CORBA request portable interceptors. In particular, we point out (i) the basic mechanisms implementable by these interceptors, i.e. request redirection and piggybacking and (ii) we analyze their limitations. We then propose a proxy-based technique to overcome the interceptors' limitations. Successively, we present a performance analysis carried out on three Java-CORBA platforms currently implementing the portable interceptors specification. Finally, we conclude our work with a case study in which portable interceptors are used to implement the fault-tolerant CORBA client invocation semantic without impacting on the client application code and on the CORBA ORB. We also release fragments of Java code for implementing the described techniques. Copyright (C) 2003 John Wiley Sons, Ltd
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The DaQuinCIS architecture: a platform for exchanging and improving data quality in cooperative information systems
No full textIn cooperative information systems, the quality of data exchanged and provided by different data sources is extremely important. A lack of attention to data quality can imply data of low quality to spread all over the cooperative system. At the same time, improvement can be based on comparing data, correcting them and thus disseminating high quality data. In this paper, we present an architecture for managing data quality in cooperative information systems, by focusing on two specific modules, the Data Quality Broker and the Quality Notification Service. The Data Quality Broker allows for querying and improving data quality values. The Quality Notification Service is specifically targeted to the dissemination of changes on data quality values. (C) 2003 Published by Elsevier Ltd
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Performance Analysis of Java Group Toolkits: A Case Study
No full textIn this paper we present a performance evaluation of three Java group toolkits (JavaGroups, Spread and Appia) with respect to a specific application scenario: software replication using a three-tier architecture. We also compare performances of these Java group toolkits with Maestro/Ensemble which has been developed in C++. Results show that performances of Java group toolkits are becoming comparable with the ones of Maestro/Ensemble, once selected a well tailored configuration for a given application
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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