A Distributed Security Architecture for Large Scale Systems

This thesis describes the research leading from the conception, through development, to the practical implementation of a comprehensive security architecture for use within, and as a value-added enhancement to, the ISO Open Systems Interconnection (OSI) model. The Comprehensive Security System (CSS) is arranged basically as an Application Layer service but can allow any of the ISO recommended security facilities to be provided at any layer of the model. It is suitable as an 'add-on' service to existing arrangements or can be fully integrated into new applications. For large scale, distributed processing operations, a network of security management centres (SMCs) is suggested, that can help to ensure that system misuse is minimised, and that flexible operation is provided in an efficient manner. The background to the OSI standards are covered in detail, followed by an introduction to security in open systems. A survey of existing techniques in formal analysis and verification is then presented. The architecture of the CSS is described in terms of a conceptual model using agents and protocols, followed by an extension of the CSS concept to a large scale network controlled by SMCs. A new approach to formal security analysis is described which is based on two main methodologies. Firstly, every function within the system is built from layers of provably secure sequences of finite state machines, using a recursive function to monitor and constrain the system to the desired state at all times. Secondly, the correctness of the protocols generated by the sequences to exchange security information and control data between agents in a distributed environment, is analysed in terms of a modified temporal Hoare logic. This is based on ideas concerning the validity of beliefs about the global state of a system as a result of actions performed by entities within the system, including the notion of timeliness. The two fundamental problems in number theory upon which the assumptions about the security of the finite state machine model rest are described, together with a comprehensive survey of the very latest progress in this area. Having assumed that the two problems will remain computationally intractable in the foreseeable future, the method is then applied to the formal analysis of some of the components of the Comprehensive Security System. A practical implementation of the CSS has been achieved as a demonstration system for a network of IBM Personal Computers connected via an Ethernet LAN, which fully meets the aims and objectives set out in Chapter 1. This implementation is described, and finally some comments are made on the possible future of research into security aspects of distributed systems.IBM (United Kingdom) Laboratories Hursley Park, Winchester, U

On the asymptotic solution of the lagerstrom model equation

The Lagerstrom equation is a one-dimensional model of the equations of viscous flow at low Reynolds numbers. It is shown how a uniformly valid asymptotic solution to the Lagerstrom equation can be obtained by an iteration procedure applied directly to an equivalent integral equation, and without recourse to inner and outer expansions

An Infrared through Radio Study of the Properties and Evolution of IRDC Clumps

We examine the physical properties and evolutionary stages of a sample of 17 clumps within 8 Infrared Dark Clouds (IRDCs) by combining existing infrared, millimeter, and radio data with new Bolocam Galactic Plane Survey (BGPS) 1.1 mm data, VLA radio continuum data, and HHT dense gas (HCO+ and N2H+) spectroscopic data. We combine literature studies of star formation tracers and dust temperatures within IRDCs with our search for ultra-compact (UC) HII regions to discuss a possible evolutionary sequence for IRDC clumps. In addition, we perform an analysis of mass tracers in IRDCs and find that 8 micron extinction masses and 1.1 mm Bolocam Galactic Plane Survey (BGPS) masses are complementary mass tracers in IRDCs except for the most active clumps (notably those containing UCHII regions), for which both mass tracers suffer biases. We find that the measured virial masses in IRDC clumps are uniformly higher than the measured dust continuum masses on the scale of ~1 pc. We use 13CO, HCO+, and N2H+ to study the molecular gas properties of IRDCs and do not see any evidence of chemical differentiation between hot and cold clumps on the scale of ~1 pc. However, both HCO+ and N2H+ are brighter in active clumps, due to an increase in temperature and/or density. We report the identification of four UCHII regions embedded within IRDC clumps and find that UCHII regions are associated with bright (>1 Jy) 24 micron point sources, and that the brightest UCHII regions are associated with "diffuse red clumps" (an extended enhancement at 8 micron). The broad stages of the discussed evolutionary sequence (from a quiescent clump to an embedded HII region) are supported by literature dust temperature estimates; however, no sequential nature can be inferred between the individual star formation tracers.Comment: 33 pages, 26 figures, 6 tables, accepted for publication in ApJ. Full resolution version available here: http://casa.colorado.edu/~battersb/Publications.htm

Room Temperature Hydrogenation of CO2 Utilizing a Cooperative Phosphorus Pyridone‐Based Iridium Complex

The synthesis, characterization and application of a new complex, [Ir(κ2-P,N-6-DCyPon*)(COD)] (1), where 6-DCyPon* is the anionic species, 6-dicyclohexylphosphino-2-oxo-pyridinide, is reported herein. Complex 1 was found to be an active catalyst in the hydrogenation of CO2 at room temperature. The ligand, 6-DCyPon*, is derived via deprotonation of a novel pro-ligand, 6-DCyPon (6-dicyclohexylphosphino-2-pyridone) during the synthesis of 1. The ligand is shown to participate within the reversible hydrogenation of 1, via a cooperative process, in which the species, [IrH3(κ2-P,N-6-DCyPon)(COD)] (2), was spectroscopically characterized, where 1 reacts with two equivalents of H2

Structure and Magnetic Fields in the Precessing Jet System SS 433 I. Multi-Frequency Imaging from 1998

The Very Large Array has been used at five frequencies to study the structure and linear polarization of SS433 on scales as small as ~0.1" ~ 500 AU. Each jet consists of a sharp, curving ridge-line at the leading edge, plus significant trailing off-jet emission, showing that they are enveloped by diffuse relativistic plasma. No kinematic model with constant jet speed fits our images on all scales, but they are consistent with variations in jet speed of around 10% around the optical value. Our images show continuous jets with bright components occurring simultaneously in the two jets roughly every 35 days. When corrected for projection effects and Doppler boosting, the intensities of the two jets are intrinsically very similar. Fractional linear polarization up to 20% is present along the ridge-lines, while the core is essentially unpolarized. The rotation measures are consistent with a foreground screen with RM ~ +110 radians per meter squared, plus a larger, asymmetrical contribution close to the core. The apparent magnetic fields in the jets are roughly aligned with the ridge-lines in most but not all of each jet. The jet is more highly polarized between the components than in the components themselves, suggesting that the mechanism that creates them compresses a tangled part of the magnetic field into a partially-ordered transverse layer. The off-jet emission is remarkably highly polarized, with m ~ 50% in places, suggesting large-scale order of the magnetic field surrounding the jets. This polarized signal may confuse the determination of magnetic field orientations in the jets themselves. However, the images are consistent with a jet magnetic field that is everywhere parallel to the helices.Comment: To appear in Ap.J. (27 pages, 12 figures

Re-examining the effects of verbal instructional type on early stage motor learning

The present study investigated the differential effects of analogy and explicit instructions on early stage motor learning and movement in a modified high jump task. Participants were randomly assigned to one of three experimental conditions: analogy, explicit light (reduced informational load), or traditional explicit (large informational load). During the two-day learning phase, participants learned a novel high jump technique based on the ‘scissors’ style using the instructions for their respective conditions. For the single-day testing phase, participants completed both a retention test and task-relevant pressure test, the latter of which featured a rising high-jump-bar pressure manipulation. Although analogy learners demonstrated slightly more efficient technique and reported fewer technical rules on average, the differences between the conditions were not statistically significant. There were, however, significant differences in joint variability with respect to instructional type, as variability was lowest for the analogy condition during both the learning and testing phases, and as a function of block, as joint variability decreased for all conditions during the learning phase. Findings suggest that reducing the informational volume of explicit instructions may mitigate the deleterious effects on performance previously associated with explicit learning in the literature

Educational Attainment at Age 10–11 Years Predicts Health Risk Behaviors and Injury Risk During Adolescence

Purpose: To examine the effect of educational attainment in primary school on later adolescent health. Methods: Education data attainments at age 7 and 11 were linked with (1) primary and secondary care injury consultation/admissions and (2) the Health Behaviour in School-aged Children survey. Cox regression was carried out to examine if attainment in primary school predicts time to injury in adolescence. Results: Pupils that achieve attainment at age 7 but not at age 11 (i.e., declining attainment over time in primary school) are more likely to have an injury during adolescence. These children are also more likely to self-report drinking in adolescence. Conclusions: Interventions aimed at children with declining attainment in primary school could help to improve adolescent health

Sticky Stories: Joe Orton, Queer History, Queer Dramaturgy

This paper investigates the resonances of Orton’s work for contemporary queer audiences. By presenting potential reasons for the rise and fall in popularity and visibility of Orton’s work for queer and gay audiences through the 1980s and 1990s, this paper looks to the queer context in which Joe Orton’s work developed in order to explore the queer social history into which it fits.  This sense of queer history is linked to contemporary notions of queer theorising about temporalities and queer dramaturgy, which offers potentially novel ways of engaging with Orton’s work queerly without twisting it to fit a ‘neat’ reading, in part because such readings tend to ‘smooth out’ the more difficult elements of the work.  In particular, the paper explores the theatrical form of farce, often articulated as conservative, in relation to queer positions, which are quite the opposite.  In so doing, the paper, by way of queer temporalities and work on queer dramaturgies, sketches out a reading strategy that does not ignore Orton’s more difficult or stickier elements, in particular his treatment of women and race

Review of the Accomplishments of Mid-latitude Super Dual Auroral Radar Network (SuperDARN) HF Radars

The Super Dual Auroral Radar Network (SuperDARN) is a network of High Frequency (HF) radars located in the high- and mid-latitude regions of both hemispheres that is operated under international cooperation. The network was originally designed for monitoring the dynamics of the ionosphere and upper atmosphere in the high-latitude regions. However, over the last approximately 15 years SuperDARN has expanded into the mid-latitude regions. With radar coverage that now extends continuously from auroral to sub-auroral and mid-latitudes a wide variety of new scientific findings have been obtained. In this paper, the background of mid-latitude SuperDARN is presented at first. Then the accomplishments made with mid-latitude SuperDARN radars are reviewed in five specified scientific and technical areas: convection, ionospheric irregularities, HF propagation analysis, ion-neutral interactions and magnetohydrodynamic (MHD) waves. Finally, the present status of mid-latitude SuperDARN is updated and directions for future research are discussed

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO