1,720,954 research outputs found
Context-based risk-adaptive security model and conflict management
No full textIn dynamic and risk-prone environments, security rules should be flexible enough to permit the treatment of risks, and to manage privileges on resources based on the situation at hand. For this purpose, we define safety-centric contexts based on risk description that is provided by the safety management system. This paper presents a riskadaptive access control model that adopts hierarchies of contexts and security domains to make adaptations to risks at different levels of criticality. Since various risks may arise simultaneously, two or more security domains might be applicable at the same time incorporating various security rules which might lead to conflicts. Therefore, an approach to analyze conflicts is essential. In this work, we propose a conflict analysis algorithm based on set theory and we illustrate its usage with the proposed risk-adaptive access control model
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
Un approccio basato sulla teoria degli insiemi per il rilevamento dei conflitti in XACML 3.0
No full textLAUREA MAGISTRALEQuesta tesi si concentra sull'analisi dei conflitti che possono esistere nella specifica di regole e policy (insiemi di regole) di sicurezza nei sistemi di controllo dell’accesso. Il modello di controllo d'accesso considerato è ABAC (Attribute Based Access Control) mentre il linguaggio di specifica di policy di accesso è XACML (eXtensible Access Control Markup Language), che permette di definire le regole di controllo dell'accesso secondo il modello ABAC. Le regole di accesso sono tuple del tipo Soggetto-Oggetto-Ambiente-Azione, che identificano in quali situazioni la regola va applicata. Quando il numero di regole di accesso cresce notevolmente, come succede nei casi reali, possono sorgere vari tipi di conflitti fra esse. In questa tesi, consideriamo che un conflitto si verifichi quando due o più regole risultano compatibili con una stessa richiesta di accesso, ma restituiscono differenti decisioni di controllo d'accesso. Il motivo è che le regole possono essere in contrasto fra loro per errori di specifica. Al contrario, se più regole forniscono la stessa decisione, siamo davanti ad un caso di ridondanza. Pur essendo meno problematiche dei conflitti, eliminare le ridondanze aiuta a ridurre il numero di regole, agevolando così la loro manutenzione da parte degli amministratori di sistema.
I vari lavori svolti per analizzare XACML e rilevare conflitti fanno riferimento a XACML 2.0, standard ormai superato. Inoltre, la maggior parte delle soluzioni proposte in letteratura sono basate sulla logica del primo ordine.
Obiettivo di questa tesi è sviluppare uno strumento di analisi dei conflitti e delle ridondanze utilizzando XACML 3.0 nell'ambito del modello di sicurezza ABAC. L’approccio al rilevamento di conflitti si differenzia dalle proposte esistenti sia per la formalizzazione, basata sulla teoria degli insiemi anziché della logica del primo ordine, sia per le prestazioni ottenute negli algoritmi realizzati per la rilevazione di conflitti. Le analisi realizzate sono esemplificate in un ambito applicativo reale, quello degli ambienti di lavoro monitorati in stile Internet of Things.This thesis focuses on the analysis of conflicts that may exist among security rules and policies (sets of rules) in access control systems. The considered access control model is ABAC (Attribute Based Access Control) while the language used to specificy policies is XACML (eXtensible Access Control Markup Language), which allows the definition of access control rules according to the ABAC model. Access rules are tuples of the type Subject-Object-Environment-Action, that identify the situations where each rule applies. When the number of access rules grows greatly, as happens in the real world, various types of conflicts may arise among them. In this thesis, we consider that a conflict occurs when two or more rules match an access request, but return different access control decisions. The reason is that the rules may be in conflict with each other due to specification errors. On the contrary, if two or more rules provide the same decision, we face a case of redundancy. Although redundancy is somehow less problematic than conflicts, eliminating redundancies helps to reduce the number of rules, thereby facilitating their maintenance by the system administrators.
Works previously done to analyze and detect XACML conflicts are based on XACML 2.0, an outdated standard. Furthermore, most of the solutions proposed in the literature are based on first order logic.
The aim of this thesis is to develop a conflict and redundancy analysis tool, using XACML 3.0, for the ABAC security model. Our approach to conflict detection differs from previous works both for its formalization with set theory, rather than first-order logic, and for the performances obtained by the algorithms implemented for conflict and redundancy detection. The tests executed through the developed tool are exemplified in a real world environment, namely a workplace monitored with an Internet of Things style
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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