An approach to knowledge engineering to support knowledge-based simulation of payload ground processing at the Kennedy Space Center

Planning for processing payloads was always difficult and time-consuming. With the advent of Space Station Freedom and its capability to support a myriad of complex payloads, the planning to support this ground processing maze involves thousands of man-hours of often tedious data manipulation. To provide the capability to analyze various processing schedules, an object oriented knowledge-based simulation environment called the Advanced Generic Accomodations Planning Environment (AGAPE) is being developed. Having nearly completed the baseline system, the emphasis in this paper is directed toward rule definition and its relation to model development and simulation. The focus is specifically on the methodologies implemented during knowledge acquisition, analysis, and representation within the AGAPE rule structure. A model is provided to illustrate the concepts presented. The approach demonstrates a framework for AGAPE rule development to assist expert system development

Risk Attitudes as an Independent Predictor of Debt

This paper examines how attitudes to risk relate to other psychological constructs of personality and consideration of future consequences (a proxy for time preferences) and how risk attitudes relate to credit behaviour and debt holdings. There is a small correlation between risk attitudes and consideration of future consequences. As regards personality, risk attitudes are most positively related to extraversion and openness to experience and are negatively related to neuroticism. Risk willingness is a robust predictor of debt holdings even controlling for demographics, personality, consideration of future consequences and other covariates.

Dosimetry of ultra-short high dose-per-pulse very high energy electrons

Detailed characterisation of a standard plane-parallel ionisation chamber has been made when exposed to high dose-per-pulse Very High Energy Electrons (VHEEs). First-of-their kind absolute dosimetry measurements using a graphite calorimeter have been conducted in a novel VHEE beam and ionisation chamber correction factors such as ion recombination have been shown to be significant. Ion recombination has been shown to increase with increasing dose-per-pulse, with a collection efficiency as low as 4% for the highest dose-per-pulse investigated, 5.26 Gy/pulse. Current theoretical recombination models provide a reasonable description of the ion recombination behaviour. Moreover, the free-electron fraction component of ion recombination models was shown to vary with dose-per-pulse, contrary to what is typically expected, and an updated model proposed in this work has been shown to provide a better fit to data than currently available recombination models. Following the experimental campaigns, Monte Carlo (MC) simulations were conducted to determine stopping-power-ratios, perturbation factors and beam quality correction factors for a reference 12 MeV beam and 200 MeV user VHEE beams using the Geant4 general purpose MC code. A Fano test was conducted and several charged particle transport parameter configurations were found to pass the Fano cavity test. Modifications to current Geant4 default physics parameters were also determined in order to provide a passing Fano test at 200 MeV. Stopping-power-ratios were found to agree within uncertainties with that found previously using EGSnrc at 12 MeV, however, perturbation factors were found to vary more than previous studies. The stopping-power-ratio at 200 MeV was found to be approximately 6% lower than what is estimated in dosimetry protocols for a reference beam quality with similar measurement depth, with a total perturbation of approximately 5%. The beam quality correction factor, for the conversion of dose from the reference beam to that of the user beam, was found to lead to an approximately 10% reduction in measured chamber dose in comparison to what was originally determined. Correction factors for the graphite calorimeter have also been calculated for the 200 MeV VHEE beam with the vacuum gap correction factor shown to be within 1% of unity. Implementation of these new corrections to early experimental data largely remedies un-physical ion chamber measurements which showed greater than 100% ion collection efficiencies for a number of collecting voltages. It is now clear that improved dosimetry for VHEEs is vital to determine reasonable and accurate characterisations of secondary standard ionisation chambers

From fate to choice - private bobbies, public beats: private security patrol and the diminishing boundaries of neighbourhood policing

Neighbourhood private security patrol as a crime control strategy demonstrates society's increasing demand for security and assurance- factors which the public police provide ineffectively. Private security's function of preventative surveillance is likely to be aligned more closely to public needs than is the public police's post-event priority of detection. Street patrol by private security personnel symbolizes an attempt by some citizens to re-create the preventative aspects of traditional policing. But it predominates only in the residential areas of the economically privileged. This demand for target-hardening, by the surveillance of whole groups and categories of people, is test described not as part of a contemporary shift from individual to collective social control, but rather as a trend away from collectivism towards active individualism. Although social and emotional influence is apparent in the rationale for this strategy, its creation also concerns the institutionalization of the classical concepts of self-help and choice - principles which are actively accede! to and encourage! by the state. In order to react to crises individuals require social confirmation for their beliefs about the reality of crime and its control. The Home Office, Police and other interesting agencies, including the Private Security Sector, provide this confirmation and they come together with communities as joint creators of new institutions. Thus, as classicist forms of control become marketable, lay-persons may participate more in policing their own neighbourhoods. This heralds the end of policing provision as fate- for as modem capitalism pluralizes it allows in private policing agents and strategies. However, while this form of control may be effective for those who choose to purchase it, there is a tendency for it to fragment rather than integrate surrounding neighbourhoods. Furthermore, it deflects crime into areas with inferior levels of surveillance. These negative aspects are not conducive to the requirements of quality and equity of justice, so crucial and intrinsic to the association policing should have with a democratic, equal and free society

Small RNAs and Immunity

AbstractSmall RNAs of 21–23 nucleotides are powerful regulators of gene expression and play essential roles in biological processes that include development, maintenance of genome stability, and viral adaptive defense mechanisms. Such small RNAs are simple in design yet rich in biology and have captivated the attention of biologists in many fields. This review discusses the potential roles of small RNAs in immune biology and speculates on their potential participation in lymphogenesis and antiviral mechanisms

A perspective on service delivery

Examins the issues in IT service delivery in technology provision

A comparison of analysis techniques for extracting resonance parameters from lattice Monte Carlo data

Different methods for extracting resonance parameters from Euclidean lattice field theory are tested. Monte Carlo simulations of the O(4) non-linear sigma model are used to generate energy spectra in a range of different volumes both below and above the inelastic threshold. The applicability of the analysis methods in the elastic region is compared. Problems which arise in the inelastic region are also emphasised.Comment: 17 pages, 20 figures; clarification and minor corrections added, to appear in PR