On Properties of Policy-Based Specifications

The advent of large-scale, complex computing systems has dramatically increased the difficulties of securing accesses to systems' resources. To ensure confidentiality and integrity, the exploitation of access control mechanisms has thus become a crucial issue in the design of modern computing systems. Among the different access control approaches proposed in the last decades, the policy-based one permits to capture, by resorting to the concept of attribute, all systems' security-relevant information and to be, at the same time, sufficiently flexible and expressive to represent the other approaches. In this paper, we move a step further to understand the effectiveness of policy-based specifications by studying how they permit to enforce traditional security properties. To support system designers in developing and maintaining policy-based specifications, we formalise also some relevant properties regarding the structure of policies. By means of a case study from the banking domain, we present real instances of such properties and outline an approach towards their automatised verification.Comment: In Proceedings WWV 2015, arXiv:1508.0338

Optimizing the computation of overriding

We introduce optimization techniques for reasoning in DLN---a recently introduced family of nonmonotonic description logics whose characterizing features appear well-suited to model the applicative examples naturally arising in biomedical domains and semantic web access control policies. Such optimizations are validated experimentally on large KBs with more than 30K axioms. Speedups exceed 1 order of magnitude. For the first time, response times compatible with real-time reasoning are obtained with nonmonotonic KBs of this size

Koka: Programming with Row Polymorphic Effect Types

We propose a programming model where effects are treated in a disciplined way, and where the potential side-effects of a function are apparent in its type signature. The type and effect of expressions can also be inferred automatically, and we describe a polymorphic type inference system based on Hindley-Milner style inference. A novel feature is that we support polymorphic effects through row-polymorphism using duplicate labels. Moreover, we show that our effects are not just syntactic labels but have a deep semantic connection to the program. For example, if an expression can be typed without an exn effect, then it will never throw an unhandled exception. Similar to Haskell's `runST` we show how we can safely encapsulate stateful operations. Through the state effect, we can also safely combine state with let-polymorphism without needing either imperative type variables or a syntactic value restriction. Finally, our system is implemented fully in a new language called Koka and has been used successfully on various small to medium-sized sample programs ranging from a Markdown processor to a tier-splitted chat application. You can try out Koka live at www.rise4fun.com/koka/tutorial.Comment: In Proceedings MSFP 2014, arXiv:1406.153

On becoming a physicist of mind

In 1976, the German Max Planck Society established a new research enterprise in psycholinguistics, which became the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands. I was fortunate enough to be invited to direct this institute. It enabled me, with my background in visual and auditory psychophysics and the theory of formal grammars and automata, to develop a long-term chronometric endeavor to dissect the process of speaking. It led, among other work, to my book Speaking (1989) and to my research team's article in Brain and Behavioral Sciences “A Theory of Lexical Access in Speech Production” (1999). When I later became president of the Royal Netherlands Academy of Arts and Sciences, I helped initiate the Women for Science research project of the Inter Academy Council, a project chaired by my physicist sister at the National Institute of Standards and Technology. As an emeritus I published a comprehensive History of Psycholinguistics (2013). As will become clear, many people inspired and joined me in these undertakings

Can We Say an Ear of Cabbage : On Translating Wordplay in Xi Xi’s Poetry

This article reflects on the translation of wordplay in the poetry of Hong Kong author Xi Xi. Xi Xi is a highly imaginative poet: much of her poetry hinges upon specificities of the Chinese language, and one might well ask if this makes her work “untranslatable.” This article identifies various techniques for translating Xi Xi’s wordplay, detailing how I mine the potential of English for ways to recreate Xi Xi’s puns, puzzles, and playful subversion of language in a new linguistic and cultural environment. It encourages readers and translators to become unshackled from rules, assumptions, and conventions as they reflect on the malleability and potential of poetry and of language itself

The syntax of polarity emphasis

A crosslinguistic survey of the expression of polarity emphasis reveals that some such expressions are subject to the distributional constraints typical of main clause phenomena, while others are not. The former have received a fairly homogeneous syntactic analysis, implicating specific left peripheral projections. The non-restricted variety, however, is not analysed uniformly with some phenomena receiving a fully syntactic account and others being accounted for in terms of semantics and pragmatics. (C) 2013 Elsevier B.V. All rights reserved

Attribution vs. possession in Coptic : The origin and development of an opposition

This paper is intended to reconstruct the process that led to the formal opposition between the patterns used for expressing possessive and attributive relationships in the Coptic language (Sahidic dialect). Having explained this opposition on a synchronic level, the following questions should be answered: What is the source of the formal likeness; How did this system develop, and what were the syntactic and semantic preconditions for such a grammaticalization? Having identified the common source, an additional question arises: How come the two constructions still differ, and do not show a complete formal identity

Do Marked Topics Enhance Memory?

We examined the effects of markedness, the deviation from the canonical Subject-Verb-Object structure in English, on the memory of listeners for the topic of the sentence. We used three marked topic constructions: Left-Dislocation, Object-Fronting, and Subject-Marking. Sentences with these structures were inserted as the 6th item in lists of 12 canonical sentences. In all sentences the topic was the name of a man. We measured recall of the critical name. The results revealed that topics of Left-Dislocated sentences were recalled more than topics of the other constructions, with topics of Object-Fronting sentences recalled the least. We briefly discuss how sentence processing procedures might give rise to these effects

Dative alternation in Indian English: a corpus-based study

The dative alternation refers to the alternation between two constructions that denote some type of transfer: the double object construction (I give my sister a book) vs. the to-dative construction (I give a book to my sister). We examined the motivations behind the dative alternation in Indian English. A corpus study was performed based on a sample of N = 943 sentences that were drawn from the Kolhapur corpus. Using a mixed-effects logistic regression analysis, we evaluated the effect of 14 predictors that are known to influence the dative alternation in other macro-regional varieties of English. Three predictors were found to be significant: the verb (modeled as a random intercept), the pronominality of the Recipient and the difference in length between the Recipient and the Theme. Our results further corroborate earlier findings that the to-dative construction is more frequently used in Indian English than in other varieties. We argue that the latter tendency may be associated with a transfer from Hindi