Expected-Delay-Summing Weak Bisimilarity for Markov Automata

A new weak bisimulation semantics is defined for Markov automata that, in addition to abstracting from internal actions, sums up the expected values of consecutive exponentially distributed delays possibly intertwined with internal actions. The resulting equivalence is shown to be a congruence with respect to parallel composition for Markov automata. Moreover, it turns out to be comparable with weak bisimilarity for timed labeled transition systems, thus constituting a step towards reconciling the semantics for stochastic time and deterministic time.Comment: In Proceedings QAPL 2015, arXiv:1509.0816

A Formal Framework for Modeling Trust and Reputation in Collective Adaptive Systems

Trust and reputation models for distributed, collaborative systems have been studied and applied in several domains, in order to stimulate cooperation while preventing selfish and malicious behaviors. Nonetheless, such models have received less attention in the process of specifying and analyzing formally the functionalities of the systems mentioned above. The objective of this paper is to define a process algebraic framework for the modeling of systems that use (i) trust and reputation to govern the interactions among nodes, and (ii) communication models characterized by a high level of adaptiveness and flexibility. Hence, we propose a formalism for verifying, through model checking techniques, the robustness of these systems with respect to the typical attacks conducted against webs of trust.Comment: In Proceedings FORECAST 2016, arXiv:1607.0200

PERBEDAAN STATUS GIZI PENDERITA KUSTA DI KOTA SEMARANG DAN DI KABUPATEN LAMONGAN

Kusta merupakan salah satu penyakit menular yang disebabkan kuman Mycobacterium leprae yang menimbulkan masalah kompleks. Status gizi didefinisikan sebagai status kesehatan yang dihasilkan dari keseimbangan antara kebutuhan dan konsumsi nutrien yang dipengaruhi langsung oleh penyakit infeksi dan tidak langsung dipengaruhi oleh lingkungan baik fisik maupun non fisik. Tujuan penelitian ini adalah menunjukan perbedaan status gizi penderita kusta di Kota Semarang dan di Kabupaten Lamongan. Penelitian ini merupakan jenis penelitian explanatory research dengan pendekatan cross sectional. Perbedaan status gizi dalam penelitian ini dilihat dari tingkat konsumsi energi dan protein yang diukur dengan Food Frequency Questionair (FFQ), indeks massa tubuh, dan tingkat pengetahuan yang diukur dengan kuesioner penelitian. Populasi dalam penelitian ini adalah penderita kusta yang melakukan rujukan ke RSUD Tugurejo dan penderita kusta di Kecamatan Brondong, Lamongan. Sampel yang diambil sebanyak 21 di Kota Semarang dengan pengambilan sampel secara quota sampling dan 21 di Kabupaten Lamongan secara purposive sampling. Analisis univariat dan bivariat menggunakan uji beda Independent T-test dan Mann-Whitney. Hasil penelitian menunjukan bahwa rerata tingkat konsumsi energi di Kota Semarang 131,7% dan di Kabupaten Lamongan 77,4%, rerata tingkat konsumsi protein 227,4% dan 147,4%, rerata indeks massa tubuh 22,1 dan 20,6, dan rerata tingkat pengetahuan 12 dan 8. Dari uji statistik diperoleh nilai signifikansi tingkat konsumsi energi p = 0,001, tingkat konsumsi protein p = 0,001, indeks massa tubuh p = 0,142, dan tingkat pengetahuan p = 0,001. Hasil penelitian menunjukan bahwa ada perbedaan tingkat konsumsi energi dan protein serta tingkat pengetahuan penderita kusta di Kota Semarang dan di Kabupaten Lamongan Kata Kunci: Kusta, Status Gizi, Kota Semarang, Kabupaten Lamonga

On the Modeling and Verification of Collective and Cooperative Systems

none1noThe formal description and verification of networks of cooperative and interacting agents is made difficult by the interplay of several different behavioral patterns, models of communication, scalability issues. In this paper, we will explore the functionalities and the expressiveness of a general-purpose process algebraic framework for the specification and model checking based analysis of collective and cooperative systems. The proposed syntactic and semantic schemes are general enough to be adapted with small modifications to heterogeneous application domains, like, e.g., crowdsourcing systems, trustworthy networks, and distributed ledger technologies.Aldini, AlessandroAldini, Alessandr

Coordination Model and Noninterference

Abstract Noninterference properties for the analysis of secure information flow are proposed in the setting of a process algebra modeling some Linda coordination primitives (asynchronous communication and read operation). To this end, relaxed definitions of equivalence are introduced that take into consideration the observational power of the external observer. The resulting taxonomy is compared with corresponding security definitions for synchronous communication models. As a result, we emphasize how the proposed coordination model affects the expressive power of some noninterference properties, by giving a new intuition to the relative merits

Non-interference for deterministic interactive programs

We consider the problem of defining an appropriate notion of non-interference (NI) for deterministic interactive programs. Previous work on the security of interactive programs by O'Neill, Clarkson and Chong (CSFW 2006) builds on earlier ideas due to Wittbold and Johnson (Symposium on Security and Privacy 1990), and argues for a notion of NI defined in terms of strategies modelling the behaviour of users. We show that, for deterministic interactive programs, it is not necessary to consider strategies and that a simple stream model of the users' behaviour is sufficient. The key technical result is that, for deterministic programs, stream-based NI implies the apparently more general strategy-based NI (in fact we consider a wider class of strategies than those of O'Neill et al). We give our results in terms of a simple notion of Input-Output Labelled Transition System, thus allowing application of the results to a large class of deterministic interactive programming languages

The relationship between perception and production of words ending in-ed by brazilian efl learners

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão. Programa de Pós-Graduação em Letras/Inglês e Literatura CorrespondenteThis research focuses on the relationship between perception and production of words ending in -ed by Brazilian learners of English as a foreign language. The relationship between perception and production was investigated in terms of the participants' ability to perceive and produce the target sound with the oral stops /p,t,k,b,d,g/ as the preceding and the semi-vowel /J/ as the following phonological environment. Thirty-two learners attending advanced English classes in the extracurricular course at Universidade Federal de Santa Catarina were tested. The hypotheses were investigated in terms of correlation and mean comparisons for /t/, /d/ and /Id/. Production data was obtained by the creation of sentences elicited through carrier phrases provided in writing. Perception data was obtained through an oddity discrimination test (Flege, Mackay & Meador, 1999). The results showed that a) there was a statistically significant and positive correlation between the perception and production of the -ed ending; b) the mean for the perception of /Id/ was significantly higher than those for /t/ and /d/; c) the mean for the perception of /t/ was significantly higher than the mean for /d/; d) the mean for the production of /Id/ was significantly higher than those for /t/ and /d/; and e) ?the mean for the production of /t/ was significantly higher than that for /d/. Results of the present study provide interesting data to be related in theoretical terms to Flege's (1995) Speech Learning Model, Best's (1995) Perceptual Assimilation Model, Hooper's (1976) Hierarchy of Strength, Selkirk's (1984) Sonority Sequencing Generalization, and Eckman's (1977, 1987) Markedness Differential Hypothesis, and corroborate the findings reported in previous studies (Koerich, 2002; Silveira, 2004) regarding voicing and the relationship between perception and production. Esta pesquisa focaliza a relação entre percepção e produção de palavras terminadas em -ed por estudantes brasileiros de inglês. A relação entre percepção e produção foi investigada em termos da habilidade dos participantes em perceber e produzir o som alvo com as plosivas orais /p,t,k,b,d,g/ como ambiente fonológico precedente e a semi-vogal /J/ como ambiente fonológico seguinte. Trinta e dois estudantes freqüentando aulas de inglês avançado no curso extracurricular da Universidade Federal de Santa Catarina foram testados. As hipóteses foram investigadas em termos de correlação e comparação de médias para /t/, /d/ e /Id/. Os dados de produção foram obtidos pela criação de sentenças a partir de 'frases guias' fornecidas por escrito. Os dados de percepção foram obtidos através de um teste de identificação do item estranho (Flege, Mackay & Meador, 1999). Os resultados mostraram que a) existe uma relação estatisticamente significativa e positiva entre a percepção e produção do -ed; b) a média na percepção do -ed pronunciado /Id/ foi significativamente maior do que as de /t/ e /d/; c) a média na percepção de /t/ foi estatisticamente significativa e maior que a de /d/; d) a média na produção de /Id/ foi significativamente maior do que as de /t/ e /d/; e e) a média na produção de /t/ foi significativamente maior do que a de /d/. Os resultados do presente estudo fornecem dados interessantes a serem relacionados em termos teóricos ao Modelo de Aprendizagem da Fala (Flege, 1995), ao Modelo de Assimilação da Percepção (Best, 1995), a Hierarquia de Sonoridade (Hooper, 1976), a Generalização da Seqüência Sonora (Selkirk, 1984), e a Hipótese da Relação da Marcação (Eckman, 1977, 1987), e ainda, corroboram os resultados de estudos prévios (Koerich, 2002; Silveira, 2004) em termos de efeito do vozeamento e da relação entre percepção e produção

Discrete Time Generative-Reactive Probabilistic Processes with Different Advancing Speeds

We present a process algebra expressing probabilistic external/internal choices, multi-way synchronizations, and processes with different advancing speeds in the context of discrete time, i.e. where time is not continuous but is represented by a sequence of discrete steps as in discrete time Markov chains (DTMCs). To this end, we introduce a variant of CSP that employs a probabilistic asynchronous parallel operator whose synchronization mechanism is based on a mixture of the classical generative and reactive models of probability. In particular, differently from existing discrete time process algebras, where parallel processes are executed in synchronous locksteps, the parallel operator that we adopt allows processes with different probabilistic advancing speeds (mean number of actions executed per time unit) to be modeled. Moreover, our generative-reactive synchronization mechanism makes it possible to always derive DTMCs in the case of fully specified systems. We then present a sound and complete axiomatization of probabilistic bisimulation over finite processes of our calculus, that is a smooth extension of the axiom system for a standard process algebra, thus solving the open problem of cleanly axiomatizing action restriction in the generative model. As a further result, we show that, when evaluating steady state based performance measures which are expressible by attaching rewards to actions, our approach provides an exact solution even if the advancing speeds are considered not to be probabilistic, without incurring the state space explosion problem that arises with standard synchronous approaches. We finally present a case study on multi-path routing showing the expressiveness of our calculus and that it makes it particularly easy to produce scalable specifications

Non-determinism in Probabilistic Timed Systems with General Distributions

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