Literate modelling: capturing business knowledge with the UML

At British Airways, we have found during several large OO projects documented using the UML that non-technical end-users, managers and business domain experts find it difficult to understand UML visual models. This leads to problems in requirement capture and review. To solve this problem, we have developed the technique of Literate Modelling. Literate Models are UML diagrams that are embedded in texts explaining the models. In that way end-users, managers and domain experts gain useful understanding of the models, whilst object-oriented analysts see exactly and precisely how the models define business requirements and imperatives. We discuss some early experiences with Literate Modelling at British Airways where it was used extensively in their Enterprise Object Modelling initiative.We explain why Literate Modelling is viewed as one of the critical success factors for this significant project. Finally, we propose that Literate Modelling may be a valuable extension to many other object-oriented and non object-oriented visual modelling languages

Mechanical component screening for scanner

The critical mechanical components of the scan mirror mechanism are described and their evaluation and screening procedures are discussed. A bumper/damper unit is used in the design to reverse motion of the mirror and effect scan and retrace cycles. A wear evaluation was conducted on the bumper impact surfaces that established nylon 6-10 as an acceptable material. The elastomeric dampers were subjected to thermal vacuum tests for condensables and outgassing as well as parametric life tests. The flexure pivots that support the mirror were tested to establish a curve of stress plotted as a function of cycles to failure for rotational operation. The pivots met the life requirement of 150,000,000 cycles at a + or - 2.9 deg amplitude during fatigue testing. Screening procedures were established for dampers and flexure pivots to obtain flight quality components

Methodology for back-contamination risk assessment for a Mars sample return mission

The risk of back-contamination from Mars Surface Sample Return (MSSR) missions is assessed. The methodology is designed to provide an assessment of the probability that a given mission design and strategy will result in accidental release of Martian organisms acquired as a result of MSSR. This is accomplished through the construction of risk models describing the mission risk elements and their impact on back-contamination probability. A conceptual framework is presented for using the risk model to evaluate mission design decisions that require a trade-off between science and planetary protection considerations

X-ray Amorphous Components of Antarctica Dry Valley Soils: Weathering Implications for Mars

The Antarctic Dry Valleys (ADV) comprise the largest ice-free region of Antarctica. Precipitation usually occurs as snow, relative humidity is frequently low, and mean annual temperatures are about -20C [1]. Substantial work has focused on soil formation in the ADVs [2], however, little work has focused on the mineralogy of secondary alteration phases. The dominant weathering process in the ADV region is physical weathering, however, chemical weathering has been well documented [3]. The occurrence of chemical weathering processes are suggested by the presence of clay minerals and iron and titanium oxides in soil. Previously we have investigated soils from two sites in the ADVs and have shown evidence of chemical weathering by the presence of clay minerals (vermiculite, smectite), short-range ordered (SRO) and/or X-ray amorphous materials, and Fe- and Tioxides as well as the presence of discrete calcite crystals [4, 5]. The Chemistry and Mineralogy (CheMin) instrument onboard the Mars Curiosity rover has detected abundant amounts (approx. 25-30 wt. %) of X-ray amorphous materials in a windblown deposit or soil (Rocknest) and in a sedimentary rocks [6,7,8]. The occurrence of large amounts of X-ray amorphous materials in Mars sediments is surprising because these materials are usually present in small quantities in terrestrial environments. The objective of this study is to further characterize the chemistry and mineralogy, specifically the secondary alteration mineralogy and the presence of X-ray amorphous material, of soils from two sites we have previously studied, a subxerous soil in Taylor Valley, and an ultraxerous soil in University Valley. While the chemical alteration processes and mineralogy of the ADV has been documented previously, there has been limited discussion on the occurrence and formation of X-ray amorphous and SRO materials in Antarctica soils. The process of aqueous alteration in the ADVs may have implications for pedogenic processes on Mars, and may lead to a better understanding to the abundance of amorphous material found in sediments in Gale crater

Fos co-operation with PTEN loss elicits keratoacanthoma not carcinoma due to p53/p21^WAF-induced differentiation triggered by GSK3b inactivation and reduced AKT activity

To investigate gene synergism in multistage skin carcinogenesis, the RU486-inducible cre/lox system was employed to ablate PTEN function [K14.cre/D5PTENflx] in mouse epidermis expressing activated v-fos [HK1.fos]. RU486-treated HK1.fos/D5PTENflx mice exhibited hyperplasia, hyperkeratosis and tumours that progressed to highly differentiated keratoacanthomas rather than carcinomas, due to re-expression of high p53 and p21WAF levels. Despite elevated MAP kinase activity, cyclin D1/E2 over expression and increased AKT activity forming areas of highly proliferative, papillomatous keratinocytes, increasing levels of GSK3b inactivation exceeded a threshold that induced p53/p21WAF expression to halt proliferation and accelerate differentiation, giving the hallmark keratosis of keratoacanthomas. A pivotal facet to this GSK3b-triggered mechanism centred on increasing p53 expression in basal layer keratinocytes. This reduced activated AKT expression and released inhibition of p21WAF, which accelerated keratinocyte differentiation, as indicated by unique basal layer expression of differentiation-specific keratin K1, alongside premature filaggrin and loricrin expression. Thus, fos synergism with PTEN loss elicited a benign tumour context where GSK3b-induced, p53/p21WAF expression continually switched AKT-associated proliferation into one of differentiation, preventing further progression. This putative compensatory mechanism required the critical availability of normal p53 and/or p21WAF otherwise deregulated fos, Akt and GSK3b associate with malignant progression

Neutrino Fluxes from Active Galaxies: a Model-Independent Analysis

There are tantalizing hints that jets, powered by supermassive black holes at the center of active galaxies, are true cosmic proton accelerators. They produce photons of TeV energy, possible higher, and may be the enigmatic source of the highest energy cosmic rays. Photoproduction of neutral pions by accelerated protons on UV light is the source of the highest energy photons, in which most of the bolometric luminosity of the galaxy may be emitted. The case that proton beams power active galaxies is, however, far from conclusive. Neutrinos from the decay of charged pions represent an uncontrovertible signature for the proton induced cascades. We show that their flux can be estimated by model-independent methods, based on dimensional analysis and textbook particle physics. Our calculations also demonstrate why different models for the proton blazar yield very similar results for the neutrino flux, consistent with the ones obtained here.Comment: Latex 2.09 with epsf.sty. 12 pages, 2 postscript figures. Compressed postscript version of paper with figures also available soon at http://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-982.ps.Z or at ftp://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-982.ps.

Working Group 5: Measurements technology and active experiments

Technology issues identified by working groups 5 are listed. (1) New instruments are needed to upgrade the ability to measure plasma properties in space. (2) Facilities should be developed for conducting a broad range of plasma experiments in space. (3) The ability to predict plasma weather within magnetospheres should be improved and a capability to modify plasma weather developed. (4) Methods of control of plasma spacecraft and spacecraft plasma interference should be upgraded. (5) The space station laboratory facilities should be designed with attention to problems of flexibility to allow for future growth. These issues are discussed