Combining MAS and P2P Systems: The Agent Trees Multi-Agent System (ATMAS)

The seamless retrieval of information distributed across networks has been one of the key goals of many systems. Early solutions involved the use of single static agents which would retrieve the unfiltered data and then process it. However, this was deemed costly and inefficient in terms of the bandwidth since complete files need to be downloaded when only a single value is often all that is required. As a result, mobile agents were developed to filter the data in situ before returning it to the user. However, mobile agents have their own associated problems, namely security and control. The Agent Trees Multi-Agent System (AT-MAS) has been developed to provide the remote processing and filtering capabilities but without the need for mobile code. It is implemented as a Peer to Peer (P2P) network of static intelligent cooperating agents, each of which control one or more data sources. This dissertation describes the two key technologies have directly influenced the design of ATMAS, Peer-to-Peer (P2P) systems and Multi-Agent Systems (MAS). P2P systems are conceptually simple, but limited in power, whereas MAS are significantly more complex but correspondingly more powerful. The resulting system exhibits the power of traditional MAS systems while retaining the simplicity of P2P systems. The dissertation describes the system in detail and analyses its performance

VOLUNTARISM AND THE CRIMINAL JUSTICE SYSTEM : A COMPARATIVE ANALYSIS

Merged with duplicate record 10026.1/735 on 14.02.2017 by CS (TIS)This thesis comparatively evaluates three groups of volunteers working within the criminal justice system in the South West of England. The groups chosen - probation Voluntary Associates, police Specials and Victims Support Scheme Volunteers - incorporate parties working with the offender, the public and the victim, ie those most closely identified with the judicial process. To date, research in both Britain and abroad has chosen to focus on a single agency which has limited our understanding of voluntarismo Nevertheless, most have identified a number of issues pertaining to the use of volunteers. Through a consideration of the type of work undertaken, motivations, who volunteers, recruitment, selection and training, and the role of the professional, this thesis attempts to link and examine these issues, to illustrate that it is possible to theorise about voluntary activity in a criminal justice context. Via interviews with 164 volunteers supported by extensive observation it has been possible to gain a more detailed insight into voluntary activity than had previously been contemplated. The findings revealed that within each organisation there. ý exists a volunteer sub-culture, (abbreviated to volunculture), which conforms to the ideology of the agency. Where a volunculture is strong, as in the case of the Specials then commitment is high; where a volunculture is weak commitment is likely to be low. The study moves on to consider the ways in which organisational policy can and does affect not only the formationof-a volunculture, _ but also its degree of strength or weakness. It is shown that presently most organisations pay lip service to the notion of using volunteers, reflected in the low status they are accorded within agency priorities. It is argued that until this is realised the wealth of helping potential that exists within communities can never be brought to the fore. Recommendations derived from volunteer perceptions and organisational policies are offered as pathfinders to achieving this objective

Atmospheric blocking and mean biases in climate models

Models often underestimate blocking in the Atlantic and Pacific basins and this can lead to errors in both weather and climate predictions. Horizontal resolution is often cited as the main culprit for blocking errors due to poorly resolved small-scale variability, the upscale effects of which help to maintain blocks. Although these processes are important for blocking, the authors show that much of the blocking error diagnosed using common methods of analysis and current climate models is directly attributable to the climatological bias of the model. This explains a large proportion of diagnosed blocking error in models used in the recent Intergovernmental Panel for Climate Change report. Furthermore, greatly improved statistics are obtained by diagnosing blocking using climate model data corrected to account for mean model biases. To the extent that mean biases may be corrected in low-resolution models, this suggests that such models may be able to generate greatly improved levels of atmospheric blocking

Navigating later life transitions: An evaluation of emotional and psychological interventions

Transitions in later life, for instance retiring from paid work, changing career, ending or starting a relationship, can have a major impact on people’s lives and their wellbeing. Recognising a gap in preventative support for transitions such as these, the Calouste Gulbenkian Foundation (CGF; UK Branch) has funded a number of projects that provide group-based psychological and emotional support as part of its Transitions in Later Life (TiLL) programme. CGF and the Centre for Ageing Better partnered on the evaluation of two of these courses — Working Longer and Living Life to the Full, a two-day course run by Cheshire and Wirral Partnership NHS Foundation Trust (CWP) and Changing Gears, a three-day course run by Age & Opportunity in Dublin, Ireland. The aim of the evaluation was to find out what impact the courses had on individual attributes that would help people be better prepared for later life transitions; what changes people make as a result of the courses; and what practice, resources or processes in the organisations are important in ensuring their implementation and efficacy

Design, production and evaluation of tactual maps for the blind

A computer-assisted system has been developed for the production of tactual mobility and orientation maps for the blind. The system involves using computer-aided design techniques to generate the input for a computer-controlled machine tool. Plastic copies are vacuum formed from an epoxy resin master. The main advantages of this system are quality, versatility and speed. Experimental studies have been undertaken on the tactual discriminability of areal, line and point symbols produced by this system. A further experiment studied the retention of meanings associated with fourteen tactual symbols and the ability of blind schoolchildren to locate these symbols on a map. A pilot study has been carried out on the acceptability of four design parameters: (i) Double and single representation of roads. (ii) Choice of plastic. (iii) Symbol elevation. (iv) Methods for marking road names. A number of tactual maps have been made for informal evaluation by a larger section of the blind community. As a result of this work a system has been evolved which can support further research in the general area of tactual representations, and which can also form the basis for a production unit to meet cone of the demands for this type of aid. It has proven possible to identify sets of symbols which may prove useful to the future design of these maps

Pulsed laser deposition of KNbO₃ thin films

The laser ablation of stationary KNbO3 single crystal targets induces a Nb enrichment of the target surface. In rotated targets this effect is observed only in those areas irradiated with low laser fluence. The composition of the plasma formed close to the target surface is congruent with the target composition; however, at further distances K-deficient films are formed due to the preferential backscattering of K in the plasma. This loss may be compensated for by using K-rich ceramic targets. Best results so far have been obtained with [K]/[Nb] = 2.85 target composition, and crystalline KNbO3 films are formed when heating the substrates to 650 °C. Films formed on (100)MgO single crystals are usually single phase and oriented with the (110) film plane parallel to the (100) substrate surface. (100)NbO may coexist with KNbO3 on (100)MgO. At substrate temperatures higher than 650 °C, niobium diffuses into MgO forming Mg4Nb2O9 and NbO, leading to K evaporation from the film. Films formed on (001) alpha-Al2O3 (sapphire) show the coexistence of (111), (110), and (001) orientations of KNbO3, and the presence of NbO2 is also observed. KNbO3 films deposited on (001)LiNbO3 crystallize with the (111) plane of the film parallel to the substrate surface. For the latter two substrates the Nb diffusion into the substrate is lower than in MgO and consequently the K concentration retained in the film is comparatively larger

Irredundant bases for finite groups of Lie type

We prove that the maximum length of an irredundant base for a primitive action of a finite simple group of Lie type is bounded above by a function which is a polynomial in the rank of the group. We give examples to show that this type of upper bound is best possible.Comment: 14 page