Opacity with Orwellian Observers and Intransitive Non-interference

Opacity is a general behavioural security scheme flexible enough to account for several specific properties. Some secret set of behaviors of a system is opaque if a passive attacker can never tell whether the observed behavior is a secret one or not. Instead of considering the case of static observability where the set of observable events is fixed off line or dynamic observability where the set of observable events changes over time depending on the history of the trace, we consider Orwellian partial observability where unobservable events are not revealed unless a downgrading event occurs in the future of the trace. We show how to verify that some regular secret is opaque for a regular language L w.r.t. an Orwellian projection while it has been proved undecidable even for a regular language L w.r.t. a general Orwellian observation function. We finally illustrate relevancy of our results by proving the equivalence between the opacity property of regular secrets w.r.t. Orwellian projection and the intransitive non-interference property

Verification of Information Flow Properties under Rational Observation

Information flow properties express the capability for an agent to infer information about secret behaviours of a partially observable system. In a language-theoretic setting, where the system behaviour is described by a language, we define the class of rational information flow properties (RIFP), where observers are modeled by finite transducers, acting on languages in a given family $\mathcal{L}$. This leads to a general decidability criterion for the verification problem of RIFPs on $\mathcal{L}$, implying PSPACE-completeness for this problem on regular languages. We show that most trace-based information flow properties studied up to now are RIFPs, including those related to selective declassification and conditional anonymity. As a consequence, we retrieve several existing decidability results that were obtained by ad-hoc proofs.Comment: 19 pages, 7 figures, version extended from AVOCS'201

Radical Islamic Terrorism in the Middle East and Its Direct Costs on Western Financial Markets

Close examination of the behaviour of participants in financial markets in the aftermath of terrorist attacks is a valuable line of enquiry. In this paper, we bring together insights from field of finance and politics. Specifically, we examine trading patterns on highly liquid insurance-type financial instruments around a specific terrorist event. This approach provides an insight into risk perception around political violence and allows us to answer a number of key questions on the impact of terrorist attacks on economies and societies. When examined and processed, intraday financial trade data yields valuable empirical evidence on immediate reactions to the threat posed by terrorist groups. The methodology applied in this paper also tells us much about the geographical resonance of terrorist events. We clearly show that fear of economic disruption can be activated in Western markets by events that are often geographically remote. Importantly, these datasets allow us to judge the vulnerability of financial markets to terrorist attack. This potentially allows public authorities to safeguard our interests more effectively. Financial markets are one important element of a "neglected home front" and the risks posed by disruption to those markets are such as to merit our urgent attention.

Price Spikes in Electricity Markets: A Strategic Perspective

This paper aims to analyze the issue of price spikes in electricity markets through the lens of noncooperative game theory. The case we consider is Australia’s long established National Electricity Market (NEM). Specifically, we adapt von der Fehr and Harbord’s multi-unit auction model to settings that more closely reflect the structure of the NEM, showing that price spikes can be related to a specifiable threshold in demand.Electricity Markets, Spot Price Behaviour, Non-Cooperative Game Theory.

Entrepreneurs need their customers’ cash, not government handouts

Many companies that grow to be large and successful never raise any venture capital. So why are we so focused on raising money and putting the investor at the centre of this entrepreneurial phenomenon? John Mullins argues that there are a lot of reasons why not to raise capital early and get customer funding instead. Once you have proven your business model and attracted paying customers, you can approach investors from a much stronger position

Probabilistic Opacity in Refinement-Based Modeling

Given a probabilistic transition system (PTS) $\cal A$ partially observed by an attacker, and an $\omega$-regular predicate $\varphi$over the traces of $\cal A$, measuring the disclosure of the secret $\varphi$ in $\cal A$ means computing the probability that an attacker who observes a run of $\cal A$ can ascertain that its trace belongs to $\varphi$. In the context of refinement, we consider specifications given as Interval-valued Discrete Time Markov Chains (IDTMCs), which are underspecified Markov chains where probabilities on edges are only required to belong to intervals. Scheduling an IDTMC $\cal S$ produces a concrete implementation as a PTS and we define the worst case disclosure of secret $\varphi$ in ${\cal S}$ as the maximal disclosure of $\varphi$ over all PTSs thus produced. We compute this value for a subclass of IDTMCs and we prove that refinement can only improve the opacity of implementations

A Time-Triggered Constraint-Based Calculus for Avionic Systems

The Integrated Modular Avionics (IMA) architec- ture and the Time-Triggered Ethernet (TTEthernet) network have emerged as the key components of a typical architecture model for recent civil aircrafts. We propose a real-time constraint-based calculus targeted at the analysis of such concepts of avionic embedded systems. We show our framework at work on the modelisation of both the (IMA) architecture and the TTEthernet network, illustrating their behavior by the well-known Flight Management System (FMS)

Oral History Interview: John Mullins

This interview is one of a series conducted concerning rural life in West Virginia. Mr. John Mullins is a native of Webster Springs, West Virginia. This interview is a discussion of his fishing and hunting experiences in Webster County since 1910.https://mds.marshall.edu/oral_history/1068/thumbnail.jp

Insights from the rat genome sequence

The availability of the rat genome sequence, and detailed three-way comparison of the rat, mouse and human genomes, is revealing a great deal about mammalian genome evolution. Together with recent developments in cloning technologies, this heralds an important phase in rat research

AN EXEMPLAR-APPRENTICE MODEL FOR TEACHING DANCE COMPOSITION THROUGH PERFORMANCE IN SECONDARY EDUCATION (NSW. AUSTRALIA)

Volume 2 and other video files are available from British Library's EThOS service.Dance education in New South Wales focuses on the three components of the artform - performance, composition and appreciation. However,, historically there has been a prescribed emphasis on performance on the assumption that performance informs composition and appreciation. In preliminary investigations, data gained via questionnaires to students; examination markers' reports; and examination results, showed the above assumption to be erroneous. It is hypothesised that, although in NSW teachers choreograph the dances performed for assessment, the emphasis on skill acquisition to achieve the highest level of performance possible mitigates against making connections between these dances and the composition components in the syllabuses. This research aimed to develop, test, and evaluate new methods of teaching these dances to simultaneously enhance students' knowledge, understanding and skill in dance composition and appreciation. The resultant Exemplar-Apprentice model -a development of the traditional master-apprentice system with the teacher functioning in concurrent roles as an exemplar-artist and as a teacher-pedagogue - is recommended because the students, as apprentices, have access to the exemplar-artist's knowledge, intuition, experience and creativity and through the teacher-pedagogue this develops a more holistic appreciation of dance as an artform. Ninety-three students from Years 10 to 12 (ages 14-17) at one sample school participated in six interventions to test the exemplar-apprentice methodology. Appropriate analytical frameworks and qualitative research instruments were employed to establish internal validity within this action research project. Analysis of the data collected supports the proposition that the Exemplar-Apprentice model can enhance knowledge, understanding and skills in dance composition and appreciation, as well as in performance. Although claims for external validity of the model are proposed, a Resource Template is offered to facilitate use of it in contexts beyond the research site. Such testing, further adaptations and applications of the Exemplar-Apprentice model by other dance teachers will extend and enhance the teaching of dance performance in NSW and across the world