An automatic abstraction technique for verifying featured, parameterised systems

A general technique combining model checking and abstraction is presented that allows property based analysis of systems consisting of an arbitrary number of featured components. We show how parameterised systems can be specified in a guarded command form with constraints placed on variables which occur in guards. We prove that results that hold for a small number of components can be shown to scale up. We then show how featured systems can be specified in a similar way, by relaxing constraints on guards. The main result is a generalisation theorem for featured systems which we apply to two well known examples

Critical complementarism and information systems: A total systems approach to computer-based information systems strategy and development

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis is about intervening in organisations to improve both operational and strategic computer-based information systems. It addresses a particular situation, in which human activity is seen to be a key factor in the success of the system. A stance is taken regarding current approaches to such development, supported by historical analysis of both the theory and practice of such approaches: in particular, the failure of traditional information systems development methodologies to address these situations is seen to question their validity. A review of existing theory and practice shows that computer-based information systems development appears to be dominated by functionalist, reductionist, engineering methods, marginally challenged by soft, interpretivist approaches. Analysis of the computer-based information systems development domain shows this to be an impoverished view, and indicates that an approach based on social systems is likely to be more representative of the problem situations faced. As a result, computer-based information systems development is taken beyond the 'hard-soft' debate, into a search for theoretical underpinning and practical approaches informed from social theory. However, whilst the theory is readily available, the application of that theory to computer-based information systems development is seen to be problematic. Potential improvement is achieved by the development of an interventionist framework which is based on a branch of social systems theory, that of critical social theory, and which draws heavily on work already undertaken in the domain of management science under the headings of critical systems thinking and total systems intervention. This framework is applied to two case studies and a major, longitudinal action research based investigation. The findings strongly support computer-based information systems development based on social, and especially critical social, theories. These findings are critiqued within the study, and from this emerge clear conclusions, and recommendations for future development

Identification, characterization, and purification of a 65,000 dalton protein in rat brain that is photolabeled by nitro-containing benzodiazepines

Benzodiazepines bind to two well-characterized classes of nanomolar-affinity binding sites, the central and the peripheral types. Although these sites appear to mediate many of the effects of these compounds, they cannot account for all of the biochemical and physiologic effects of the benzodiazepines. In this investigation, a protein that is photolabeled by NO2-containing benzodiazepines was identified and characterized in rat brain by performing photaffinity labeling experiments with [3H] -clonazepam and [3H] -flunitrazepam. These experiments demonstrate that this photolabeled protein has a molecular weight of 65,000 daltons. Photolabeling of the protein was saturable, inhibited in a stereoselective manner by benzodiazepine enantiomers, inhibited by therapeutically-relevant concentrations of many different NO2-containing benzodiazepines, and was not inhibited by more than 70 non-benzodiazepine compounds. The photolabeled protein is distinct from the central and peripheral sites on the basis of molecular weight, benzodiazepine inhibitory potencies, subcellular localization, and tissue distribution.The protein was purified to apparent homogeneity by Affi-Gel Blue and Agarose Green column chromatography. This two-column purification scheme resulted in a greater than 2000-fold enrichment of the protein with a yield of 35%. Biochemical studies on the purified preparation established that the protein exists as a monomer in the purified state, contains a high relative abundance of glycine residues, and possesses amino acid sequence homology with the beta chain of hemoglobin.This newly-characterized protein may mediate some of the effects of the benzodiazepines that are not associated with the central- or peripheral-type sites. It is also possible that the protein is an enzyme that synthesizes or degrades benzodiazepines

The development impact of remittances to Nicaragua

Workers\u27 remittances represent a resource flow from rich to poor countries. The global value of remittances has risen sharply to over US$100 billion a year. This represents the second largest external income source for developing countries behind foreign direct investment (FDI), and far outstrips official development assistance (ODA) (Orozco 2003a). Remittances to developing countries are becoming increasingly important as other sources of external income decline. The impact of remittances on development, however, is inadequately reflected in the literature. Latin America and the Caribbean (LAC) is the world\u27s largest remittance-receiving region. With 9 per cent of the world\u27s population, the region receives approximately 32 per cent of the world\u27s remittances. It is appreciably greater than tourist revenues in many countries, and in five countries in this region, remittances account for over 10 per cent of GNP (World Bank 2003). Within LAC, Nicaragua stands out from other countries. While the US dollar value of remittances to Nicaragua, estimated at US$610 million in 2001, is quite modest compared with the US$10 billion flowing into Mexico, for example, the relative volume of this resource compared with other income flows, and the potential for the country\u27s development, makes Nicaragua\u27s case exceptional. Representing almost 24 per cent of its GNP, remittances to Nicaragua have a significant social and economic impact. The value of known remittances is greater than total export earnings, on a par with the country\u27s ODA, and almost five times that of FDI. As such, remittances currently represent the second largest single resource flow into the country. This is a recent phenomenon.<br /

When images work faster than words: The integration of content-based image retrieval with the Northumbria Watermark Archive

Information on the manufacture, history, provenance, identification, care and conservation of paper-based artwork/objects is disparate and not always readily available. The Northumbria Watermark Archive will incorporate such material into a database, which will be made freely available on the Internet providing an invaluable resource for conservation, research and education. The efficiency of a database is highly dependant on its search mechanism. Text based mechanisms are frequently ineffective when a range of descriptive terminologies might be used i.e. when describing images or translating from foreign languages. In such cases a Content Based Image Retrieval (CBIR) system can be more effective. Watermarks provide paper with unique visual identification characteristics and have been used to provide a point of entry to the archive that is more efficient and effective than a text based search mechanism. The research carried out has the potential to be applied to any numerically large collection of images with distinctive features of colour, shape or texture i.e. coins, architectural features, picture frame profiles, hallmarks, Japanese artists stamps etc. Although the establishment of an electronic archive incorporating a CBIR system can undoubtedly improve access to large collections of images and related data, the development is rarely trouble free. This paper discusses some of the issues that must be considered i.e. collaboration between disciplines; project management; copying and digitising objects; content based image retrieval; the Northumbria Watermark Archive; the use of standardised terminology within a database as well as copyright issues

Space weather effects on drilling accuracy in the North Sea

The oil industry uses geomagnetic field information to aid directional drilling operations when drilling for oil and gas offshore. These operations involve continuous monitoring of the azimuth and inclination of the well path to ensure the target is reached and, for safety reasons, to avoid collisions with existing wells. Although the most accurate method of achieving this is through a gyroscopic survey, this can be time consuming and expensive. An alternative method is a magnetic survey, where measurements while drilling (MWD) are made along the well by magnetometers housed in a tool within the drill string. These MWD magnetic surveys require estimates of the Earth’s magnetic field at the drilling location to correct the downhole magnetometer readings. The most accurate corrections are obtained if all sources of the Earth’s magnetic field are considered. Estimates of the main field generated in the core and the local crustal field can be obtained using mathematical models derived from suitable data sets. In order to quantify the external field, an analysis of UK observatory data from 1983 to 2004 has been carried out. By accounting for the external field, the directional error associated with estimated field values at a mid-latitude oil well (55 N) in the North Sea is shown to be reduced by the order of 20%. This improvement varies with latitude, local time, season and phase of the geomagnetic activity cycle. By accounting for all sources of the field, using a technique called Interpolation In-Field Referencing (IIFR), directional drillers have access to data from a “virtual” magnetic observatory at the drill site. This leads to an error reduction in positional accuracy that is close to matching that of the gyroscopic survey method and provides a valuable independent technique for quality control purposes

Effective teaching

This initiative focuses on providing an understanding of both students’ and teachers’ perceptions of effective teaching in a modern UK University. Through utilising a phenomenographical perspective, the research identifies that teacher effectiveness is a combination of providing a supportive environment and including students in the process of developing understanding. This research has been carried out in four schools within the University of Wolverhampton and five constituents of effective teaching have been identified.HEFC

Wrinkling of a bilayer membrane

The buckling of elastic bodies is a common phenomenon in the mechanics of solids. Wrinkling of membranes can often be interpreted as buckling under constraints that prohibit large amplitude deformation. We present a combination of analytic calculations, experiments, and simulations to understand wrinkling patterns generated in a bilayer membrane. The model membrane is composed of a flexible spherical shell that is under tension and that is circumscribed by a stiff, essentially incompressible strip with bending modulus B. When the tension is reduced sufficiently to a value \sigma, the strip forms wrinkles with a uniform wavelength found theoretically and experimentally to be \lambda = 2\pi(B/\sigma)^{1/3}. Defects in this pattern appear for rapid changes in tension. Comparison between experiment and simulation further shows that, with larger reduction of tension, a second generation of wrinkles with longer wavelength appears only when B is sufficiently small.Comment: 9 pages, 5 color figure

Using websites to disseminate research on urban spatialities

This paper reviews a selection of websites that explore urban geographies. Many sites use the web as a depository for large amounts of research data. However, many are using websites to disseminate research findings, and the paper focuses on these. It suggests that, thus far, there are three significant ways in which urban researchers are exploiting the potentialities of web technologies to interpret urban spaces: by evoking a sense of the complexity of urban spatialities; by inviting site visitors to engage actively and performatively with the research materials; and by emphasising the sensory qualities of urban spaces. The paper discusses how one website in particular invites its visitors to engage with complex, sensory urban spatialities. The paper compares geographers' use of collage and montage as part of this discussion, and ends by reflecting on current work and commenting on its future development

(2S,3S)-3-(4-Chloro­phen­yl)-8-methyl­tropane-2-carboxylic acid

In the title compound, C15H18ClNO2, the inter­nal torsion angles of the tropane ring are comparable to those of tropane rings in the crystal structures reported for cocaine and its derivatives. There is an intra­molecular hydrogen bond between the N atom in the tropane ring and the O atom of the carboxyl group. The crystal structure is further stabilized by many weak C—H⋯O inter­actions between the mol­ecules in the ab plane, forming a two-dimensional supra­molecular network