Towards a method for rigorous development of generic requirements patterns

We present work in progress on a method for the engineering, validation and verification of generic requirements using domain engineering and formal methods. The need to develop a generic requirement set for subsequent system instantiation is complicated by the addition of the high levels of verification demanded by safety-critical domains such as avionics. Our chosen application domain is the failure detection and management function for engine control systems: here generic requirements drive a software product line of target systems. A pilot formal specification and design exercise is undertaken on a small (twosensor) system element. This exercise has a number of aims: to support the domain analysis, to gain a view of appropriate design abstractions, for a B novice to gain experience in the B method and tools, and to evaluate the usability and utility of that method.We also present a prototype method for the production and verification of a generic requirement set in our UML-based formal notation, UML-B, and tooling developed in support. The formal verification both of the structural generic requirement set, and of a particular application, is achieved via translation to the formal specification language, B, using our U2B and ProB tools

Computation of thermodynamic and transport properties to predict thermophoretic effects in an argon-krypton mixture

Thermophoresis is the movement of molecules caused by a temperature gradient. Here we report the results of a study of thermophoresis using non-equilibrium molecular dynamics simulations of a confined argon-krypton fluid subject to two different temperatures at thermostated walls. The resulting temperature profile between the walls is used along with the Soret coefficient to predict the concentration profile that develops across the channel. We obtain the Soret coefficient by calculating the mutual diffusion and thermal diffusion coefficients. We report an appropriate method for calculating the transport coefficients for binary systems, using the Green-Kubo integrals and radial distribution functions obtained from equilibrium molecular dynamics simulations of the bulk fluid. Our method has the unique advantage of separating the mutual diffusion and thermal diffusion coef- ficients, and calculating the sign and magnitude of their individual contributions to thermophoresis in binary mixtures

Sustainable management of miombo woodlands in the Northern part of Mozambique (Niassa National Reserve - NNR).

Poster presented at Commiting Science to Global Development. Lisbon (Portugal). 29-30 Sep 2009

The chemistry of quartz in granitic pegmatites of southern Norway: Petrogenetic and economic implications

This is the author accepted manuscript. The final version is available from Society of Economic Geologists via the DOI in this record.Trace element concentrations in quartz from 188 granitic pegmatites in the Froland and Evje-Iveland pegmatite fields, southern Norway, have been determined to establish exploration targets for high-purity quartz and to gain a better understanding of the genesis of pegmatites hosting these deposits. Both pegmatite fields were formed during the Sveconorwegian (Grenvillian) orogeny (1145-900 Ma) at the western margin of the Fennoscandian Shield. In situ raster analyses within single quartz crystals were undertaken by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS); spot size 75 μm) to assess levels of lattice-bound impurities, rather than mineral and fluid inclusions that are relatively easily removed during high-purity quartz processing. Quartz in the Froland pegmatites has relatively pure and homogeneous compositions containing 46 ± 24 μgg-1Al, 8 ± 3 μgg-1Ti, 1.4 ± 0.8 μgg-1Ge, and 11 ± 7 μgg-1Li. The Ti-in-quartz geothermobarometer gives an average pegmatite crystallization temperature of 537° ± 39°C. Temperature estimates are highest along the northwestern margin of the pegmatite field (>550°C), whereas the most differentiated pegmatites occur toward the northeast. The area of greatest economic potential for high-purity quartz lies just north of the central part of the field where individual pegmatites contain >1 million metric tons (Mt) quartz with low average trace element contents of 67 ± 11 μgg-1. From mineral-chemical criteria, and a range of other geologic factors, we propose that pegmatite melts in the Froland field were generated by fluid-present crustal melting at about 1060 Ma, in zones of localized high-strain deformation during progressive thrusting along the Porsgrunn-Kristiansand fault zone. Quartz in the Evje-Iveland pegmatites has more variable compositions with 69 ± 57 μgg-1Al, 19 ± 11 μgg-1Ti, 2.3 ± 1.8 μgg-1Ge, and 7 ± 5 μgg-1Li. From its Ti content, it crystallized at temperatures of 613° ± 70°C. The regional spatial distribution of Ti-in-quartz temperatures appears irregular mainly due to the scattered distributions of chemical evolved pegmatites with "amazonite"-"cleavelandite" replacement zones, which show crystallization temperatures down to 442°C. Quartz from the Evje-Iveland pegmatites is unlikely to be of current economic interest due to its moderate to high trace element contents, heterogeneous chemistry, and low volume. The Evje-Iveland pegmatites show no apparent genetic link to a granite intrusion; instead they probably formed as a result of partial melting at the depth of their amphibolite country rocks at around 910 Ma. This is related to a regional low-pressure/high-temperature metamorphic event at about 930 to 920 Ma.Geological Survey of Norway in Trondhei

New Langevin and Gradient Thermostats for Rigid Body Dynamics

We introduce two new thermostats, one of Langevin type and one of gradient (Brownian) type, for rigid body dynamics. We formulate rotation using the quaternion representation of angular coordinates; both thermostats preserve the unit length of quaternions. The Langevin thermostat also ensures that the conjugate angular momenta stay within the tangent space of the quaternion coordinates, as required by the Hamiltonian dynamics of rigid bodies. We have constructed three geometric numerical integrators for the Langevin thermostat and one for the gradient thermostat. The numerical integrators reflect key properties of the thermostats themselves. Namely, they all preserve the unit length of quaternions, automatically, without the need of a projection onto the unit sphere. The Langevin integrators also ensure that the angular momenta remain within the tangent space of the quaternion coordinates. The Langevin integrators are quasi-symplectic and of weak order two. The numerical method for the gradient thermostat is of weak order one. Its construction exploits ideas of Lie-group type integrators for differential equations on manifolds. We numerically compare the discretization errors of the Langevin integrators, as well as the efficiency of the gradient integrator compared to the Langevin ones when used in the simulation of rigid TIP4P water model with smoothly truncated electrostatic interactions. We observe that the gradient integrator is computationally less efficient than the Langevin integrators. We also compare the relative accuracy of the Langevin integrators in evaluating various static quantities and give recommendations as to the choice of an appropriate integrator.Comment: 16 pages, 4 figure

Registration of the Maize Population Zapalote Chico 2451F

Zapalote Chico 2451F (ZC-2451F) (Reg. no. GP-370, PI 618810), a maize (Zea mays L.) germplasm population was released in April 2001 by the Florida Agricultural Experiment Station and the USDA-ARS Crop Genetics and Breeding Research Unit. This population was released as a source of improved resistance to silk and ear feeding by larvae of the corn silk fly [Euxesta stigmatias Loew. (Diptera: Otitidae)], the fall armyworm [Spodoptera frugiperda (J.E. Smith)], and the corn earworm [Heliocoverpa zea (Boddie) (Lepidoptera: Noctuidae)]. Zapalote Chico 2451F is distinct from Shrunken Zapalote Chico (ZC-sh2) (PI 612343), and the Zapalote Chico land race collected in the state of Oaxaca, Mexico, in the late 1940s, and first acceded to the National Seed Storage Laboratory as PI 217413 (Scully et al., 2000; Anderson, 1959; Straub and Fairchild, 1970). PI 217413 was one of the earliest Zapalote Chico populations identified as a source of natural compounds with insecticidal properties (Wais et al., 1979;Wilson and Wiseman, 1988). Resistance in Zapalote Chico 2451F is also due to elevated levels of the flavone glycoside maysin that is found in fresh silk (Ellinger et al., 1980; Snook et al., development of new germplasms or parental lines. 1993, 1995). Maysin is synthesized in the flavonoid pathway W.L. Rooney and known to specifically confer antibiosis-based resistance to silk feeding (Byrne et al., 1996)

Asymptotic analysis for the generalized langevin equation

Various qualitative properties of solutions to the generalized Langevin equation (GLE) in a periodic or a confining potential are studied in this paper. We consider a class of quasi-Markovian GLEs, similar to the model that was introduced in \cite{EPR99}. Geometric ergodicity, a homogenization theorem (invariance principle), short time asymptotics and the white noise limit are studied. Our proofs are based on a careful analysis of a hypoelliptic operator which is the generator of an auxiliary Markov process. Systematic use of the recently developed theory of hypocoercivity \cite{Vil04HPI} is made.Comment: 27 pages, no figures. Submitted to Nonlinearity

Boundary lubrication properties of materials with expansive freezing

We have performed molecular dynamics simulations of solid-solid contacts lubricated by a model fluid displaying many of the properties of water, particularly its expansive freezing. Near the region where expansive freezing occurs, the lubricating film remains fluid, and the friction force decreases linearly as the shear velocity is reduced. No sign of stick-slip motion is observed even at the lowest velocities. We give a simple interpretation of these results, and suggest that in general good boundary lubrication properties will be found in the family of materials with expansive freezing.Comment: Version to appear in Phys. Rev. Let

From Theory to Practice: Forging a Collaborative Evaluation Strategy for a Culturally-Informed Domestic Violence Initiative

Community programs for domestic violence (DV) in the U.S. have historically focused on White populations. Few programs exist to meet the needs of racial/ethnic minority populations, including Latinx women, who encounter greater barriers to access services than their non-Hispanic White counterparts. Casa de Esperanza is one of the few organizations in the U.S. focused on addressing the unique needs of Latinx survivors of DV. In particular, their Family Advocacy Initiative (FAI) seeks to support Latinx communities impacted by DV by facilitating a variety of services including a 24-hour hotline, shelter, community advocacy, and transitional housing support network. This program utilizes Casa de Esperanza’s Latina Advocacy Framework, which was developed to address the unique risks, considerations, and needs of Latinx communities, but has yet to be empirically evaluated. As part of a graduate community psychology course on assessment, consultation, and evaluation, a university-community partnership was established to explore the process of defining, designing, and planning an evaluation of Casa de Esperanza’s FAI. This paper describes the university team’s process in learning about Casa de Esperanza and the FAI and collaboratively developing an evaluation plan. We briefly summarize the program’s theory of change, review its logic model, and present results from a focus group conducted with program staff. Based on this information we discuss the evaluation and recommendations for implementing it. Throughout the paper, we highlight the need for culturally sensitive programs for survivors of DV and the importance and benefits of collaborative community partnerships and evidence-based evaluative learning

From Theory to Practice: Forging a Collaborative Evaluation Strategy for a Culturally-Informed Domestic Violence Initiative

Community programs for domestic violence (DV) in the U.S. have historically focused on White populations. Few programs exist to meet the needs of racial/ethnic minority populations, including Latinx women, who encounter greater barriers to access services than their non-Hispanic White counterparts. Casa de Esperanza is one of the few organizations in the U.S. focused on addressing the unique needs of Latinx survivors of DV. In particular, their Family Advocacy Initiative (FAI) seeks to support Latinx communities impacted by DV by facilitating a variety of services including a 24-hour hotline, shelter, community advocacy, and transitional housing support network. This program utilizes Casa de Esperanza’s Latina Advocacy Framework, which was developed to address the unique risks, considerations, and needs of Latinx communities, but has yet to be empirically evaluated. As part of a graduate community psychology course on assessment, consultation, and evaluation, a university-community partnership was established to explore the process of defining, designing, and planning an evaluation of Casa de Esperanza’s FAI. This paper describes the university team’s process in learning about Casa de Esperanza and the FAI and collaboratively developing an evaluation plan. We briefly summarize the program’s theory of change, review its logic model, and present results from a focus group conducted with program staff. Based on this information we discuss the evaluation and recommendations for implementing it. Throughout the paper, we highlight the need for culturally sensitive programs for survivors of DV and the importance and benefits of collaborative community partnerships and evidence-based evaluative learning