http://dspace1.isd.glam.ac.uk:80/dspace/handle/10265/118 2013-05-22T12:22:14Z http://dspace1.isd.glam.ac.uk:80/dspace/handle/10265/637 Title: Improving the impact resistance of masonry parapet walls Authors: Hobbs, Brian Abstract: In the UK and other countries roadside masonry parapet walls are commonplace. Such walls were, however, generally not designed from the outset to resist out-of-plane impact loadings from highway vehicles. The consequences of an impact can obviously be severe, particularly in the case of railway overbridges. Following a programme of experimental impact tests performed in the 1990s on unreinforced masonry walls, this paper describes an investigation of the performance of reinforced masonry walls, tested under carefully controlled conditions in the laboratory. A total of 17 tests were performed on unreinforced and reinforced walls. The reinforced walls incorporated either bed joint reinforcement or one of two different types of drilled-in reinforcement. Whereas the bed-joint reinforcement was found to be largely ineffectual, the drilled-in reinforcing systems were found to be capable of enhancing the ability of plain masonry walls to resist impacts, ensuring a ductile response to the applied transient loading. The effect of drilled-in reinforcement on the resistance of walls with low-strength mortar was found to be particularly dramatic, changing the response from that of penetration and disintegration of the masonry to ductile behaviour, with the integrity of the wall maintained and only minimal wall displacement. 2013-01-03T00:00:00Z http://dspace1.isd.glam.ac.uk:80/dspace/handle/10265/522 Title: On the (un-)decidability of model-checking resource-bounded agents Authors: Muller, Berndt Abstract: The verification and modelling of multi-agent systems is an important topic that has attracted much attention in recent years. Resources, however, have only recently been studied as simple extensions to well-known logics. Trying to find a set of useful features while retaining essential properties for practical use, we explore the question: Where are the limits of what can be verified about resource-bounded agents? We try to answer this question by considering several natural logic-based settings that may arise and prove that verification is usually undecidable apart from bounded or otherwise restrictive settings. Most interestingly, we identify various factors that influence the (un-)decidability and provide grounds for future research on more promising constraints leading to decidable fragments. 2012-05-02T23:00:00Z http://dspace1.isd.glam.ac.uk:80/dspace/handle/10265/517 Title: A unified approach to network traffic and network security visualisation Authors: Read, Huw O.; Blyth, Andrew J.; Sutherland, Iain Abstract: In this paper we present an architecture which enables data-sharing between computer security and network traffic visualisation tools. At its core is a middleware which manages all interactions. This enables one application to determine the acceptable input for another, and send compatible data. The middleware sits atop a unified database which provides data in a generic form to the applications. Interesting traffic patterns or attack trends seen in one tool can be sent directly to another for further examination and analysis. All communication in the middleware is performed using XML as a data transport mechanism. 2012-05-01T23:00:00Z http://dspace1.isd.glam.ac.uk:80/dspace/handle/10265/516 Title: Expressing properties of resource-bounded systems: the Logics RTL* and RTL Authors: Muller, Berndt Abstract: Computation systems and logics for modelling such systems have been studied to a great extent in the past decades. This paper introduces resources into the models of systems and discusses the Resource-Bounded Tree Logics RTL and RTL*, based on the well-known Computation Tree Logics CTL and CTL*, for reasoning about computations of such systems. We present initial results on the complexity/decidability of model checking. 2012-05-01T23:00:00Z