A counter abstraction technique for the verification of robot swarms.

We study parameterised verification of robot swarms against temporal-epistemic specifications. We relax some of the significant restrictions assumed in the literature and present a counter abstraction approach that enable us to verify a potentially much smaller abstract model when checking a formula on a swarm of any size. We present an implementation and discuss experimental results obtained for the alpha algorithm for robot swarms

Verifying Security Properties in Unbounded Multiagent Systems

We study the problem of analysing the security for an unbounded number of concurrent sessions of a cryptographic protocol. Our formal model accounts for an arbitrary number of agents involved in a protocol-exchange which is subverted by a Dolev-Yao attacker. We define the parameterised model checking problem with respect to security requirements expressed in temporal-epistemic logics. We formulate sufficient conditions for solving this problem, by analysing several finite models of the system. We primarily explore authentication and key-establishment as part of a larger class of protocols and security requirements amenable to our methodology. We introduce a tool implementing the technique, and we validate it by verifying the NSPK and ASRPC protocols

THE CRETAN CONFLICT 1866-1869: COMPETING AND COMPLEMENTARY IDEOLOGIES THROUGH THE PRISM OF THE GREEK AND OTTOMAN PRESS

Crete was historically one of the most turbulent provinces of the Ottoman Empire. The present doctoral dissertation focuses on the uprising during 1866-1869, while ex-amining it within the ideological context reflected in the publications of the Greek and Ottoman press of the time. From the presentation of the findings, it is obvious that the events in Crete not only developed within a more general resurgence of the ideological currents of the period, such as the expansive Greek megaloideatism, the unifying Ottomanism, and the ag-gressive Pan-Slavism, but to a certain extent they were made even more acute. How-ever, the attitude of the Constantinopolitan Greek newspapers on the specific issue revealed the existence of a new ideological phenomenon, that of Greek Ottomanism, which could be discerned mainly in the members of the upper class of the Greek mil-let. This phenomenon was a by-product of Ottomanism, and was linked to the desire of the Greek bourgeoisie in the Ottoman Empire to safeguard its privileges in a changing environment, while at the same time distancing itself from the ideological narrative of the Great Idea. In conclusion, the contemporary Ottoman and Greek language press not only recorded the historical event of the uprising but also became an important means of expression of all the above ideologies which characterised the developments in the area during the 2nd half of the 19th century

The Old Greeks

In his final unfinished book on the writing of history, Siegfried Kracauer wonders about his increasing susceptibility to ‘the speechless plea of the dead’. ‘[T]he older one grows, the more he is bound to realize that his future is the future of the past—history.’ For the children of migrants, the question of how to speak well of the dead is distinguished by complex feelings of attachment and rejection, identification and denial that are expressed in a range of everyday interactions. ‘The Old Greeks’ examines the part played by photographic media in this process of memorialisation. It elaborates a series of propositions about the value of photographic media that are tested through a consideration of the events that surrounded the author’s first years in Australia

Formal verification of neural agents in non-deterministic environments

We introduce a model for agent-environment systems where the agents are implemented via feed-forward ReLU neural networks and the environment is non-deterministic. We study the verification problem of such systems against CTL properties. We show that verifying these systems against reachability properties is undecidable. We introduce a bounded fragment of CTL, show its usefulness in identifying shallow bugs in the system, and prove that the verification problem against specifications in bounded CTL is in coNEXPTIME and PSPACE-hard. We introduce sequential and parallel algorithms for MILP-based verification of agent-environment systems, present an implementation, and report the experimental results obtained against a variant of the VerticalCAS use-case and the frozen lake scenario

The virtues of idleness: a decidable fragment of resource agent logic

Alternating Time Temporal Logic (ATL) is widely used for the verification of multi-agent systems. We consider Resource Agent Logic (RAL), which extends ATL to allow the verification of properties of systems where agents act under resource constraints. The model checking problem for RAL with unbounded production and consumption of resources is known to be undecidable. We review existing (un)decidability results for fragments of RAL, tighten some existing undecidability results, and identify several aspects which affect decidability of model checking. One of these aspects is the availability of a ‘do nothing’, or idle action, which does not produce or consume resources. Analysis of undecidability results allows us to identify a significant new fragment of RAL for which model checking is decidable

Adenosine A2A receptors facilitate synaptic NMDA currents in CA1 pyramidal neurons

© 2018 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.Background and purpose: NMDA receptors play a key role in both synaptic plasticity and neurodegeneration. Adenosine is an endogenous neuromodulator and through membrane receptors of the A2A subtype can influence both synaptic plasticity and neuronal death. The present work was designed to evaluate the influence of adenosine A2A receptors upon NMDA receptor activity in CA1 hippocampal neurons. We discriminated between modulation of synaptic versus extrasynaptic receptors, since extrasynaptic NMDA receptors are mostly associated with neurodegeneration while synaptic NMDA receptors are linked to plasticity phenomena. Experimental approach: Whole-cell patch-clamp recordings were obtained to evaluate NMDA receptor actions on CA1 pyramidal neurons of young adult (5-10 weeks) male Wistar rat hippocampus. Key results: Activation of A2A receptors with CGS 21680 (30 nM) consistently facilitated chemically-evoked NMDA receptor-currents (NMDA-PSCs) and afferent-evoked NMDA-currents (NMDA-EPSCs), an action prevented by an A2A receptor antagonist (SCH58261, 100 nM) and a PKA inhibitor, H-89 (1 μM). These actions did not reflect facilitation in glutamate release since there was no change in NMDA-EPSCs paired pulse ratio. A2A receptor actions were lost in the presence of an open-channel NMDA receptor blocker, MK-801 (10 μM), but persisted in the presence of memantine, at a concentration (10 μM) known to preferentially block extrasynaptic NMDA receptors. Conclusion and implications: These results show that A2A receptors exert a positive postsynaptic modulatory effect over synaptic, but not extrasynaptic, NMDA receptors in CA1 neurons and, therefore, under non-pathological conditions may contribute to shift the dual role of NMDA receptors towards enhancement of synaptic plasticity.Work supported by LISBOA-01-0145-FEDER-007391, project co-funded by FEDER through POR Lisboa 2020 (Programa Operacional Regional de Lisboa) from PORTUGAL 2020 and Fundação para a Ciência e Tecnologia, (FCT), by an FCT project (PTDC/DTP-FTO/3346/2014), and by a Twinning action (SynaNet) from the EU H2020 programme (project number: 692340). F.M.M. was in receipt of SFRH/BD/89582/2012 FTC fellowship, and D.M.R. is in receipt of a fellowship from Instituto de Medicina Molecular (IMM/BI/38-2017).info:eu-repo/semantics/publishedVersio