967 research outputs found
Building a refinement checker for Z
In previous work we have described how refinements can be checked using a
temporal logic based model-checker, and how we have built a model-checker for Z
by providing a translation of Z into the SAL input language. In this paper we
draw these two strands of work together and discuss how we have implemented
refinement checking in our Z2SAL toolset.
The net effect of this work is that the SAL toolset can be used to check
refinements between Z specifications supplied as input files written in the
LaTeX mark-up. Two examples are used to illustrate the approach and compare it
with a manual translation and refinement check.Comment: In Proceedings Refine 2011, arXiv:1106.348
Overview of the proceedings of the 2019 Inclusion in Science, Learning a New Direction Conference on Disability (ISLAND)
The 10th annual Inclusion in Science, Learning a New Direction Conference on Disability (ISLAND) was hosted by the University of Alabama in Huntsville (UAH), with support from the UAH College of Education, UAH Office of Academic Affairs, and the Alabama Institute for the Deaf and Blind, as well as the Princeton Center for Complex Materials (PCCM), a National Science Foundation funded Materials Research Science and Engineering Center (MRSEC) and the UAH Center for Cybersecurity Research and Education (CCRE). On October 4-5, 2019, the conference was held at the U.S. Space and Rocket Center facility and at the new Student Services Building on the UAH campus. This year’s presentations included innovative research by science educators in formal and informal educational settings, from pre-K-12 to higher education, as well as from science education researchers, access technology developers, and other persons interested in the promotion of the full inclusion of people with disabilities in Science, Technology, Engineering, and Mathematics (STEM) professions. The 2019 ISLAND conference featured seventeen presentations over the two-day period. The following is intended to give the reader an overview of these presentations. This is not intended to be a comprehensive synopsis of all aspects of the discussions that were presented. Rather, readers are encouraged to review full papers authored by the presenters highlighted herein. All presenters were invited to contribute papers to this special section of JSESD
Evolution of mammalian social structure
Social groups may be viewed as collections of individuals exhibiting nonindependent behavior and organized in a cooperative manner. The evolutionary advantage of social behavior to individuals must be measured in its relativity to other potential behaviors, the scale of competitive interactions, and under a variety of environmental and genetic constraints. A primary tenet of social evolution is that coancestry will promote the genes of related individuals. High values of coancestry, however, do not necessarily translate into evolutionary advantage unless the primary competitive interactions occur among the groups. Coancestry is affected by the breeding tactics within and rates of genetic exchange among social groups. Low rates of exchange among groups, regardless of breeding tactics, may result in high values for intragroup coancestry but may lead to inbreeding depression in progeny. Likewise, breeding tactics such as polygyny, may not impart any long-lasting evolutionary advantage if genetic exchange rates are high. The evolution of social organizations typified by different breeding and migration strategies is evaluated to determine the conditions necessary for various tactics to result in genetic contributions by individuals equal to those of monogamous mating systems. The models show that breeding and dispersal tactics have probably evolved in concert and predict that social groups which are characterized by strong gene correlations are likely to exhibit relatively low group advantage for progeny survival and breeding. There is little impetus for high gene correlations to accrue in situations where group advantage is very high relative to monogamous systems
Teaching Cybersecurity to Students with Visual Impairments and Blindness
This work showcases specific adaptations used to make cybersecurity accessible to high school students with visual impairments and blindness (VIB). The rapidly growing field of cybersecurity demands a diverse workforce; however, barriers exist which can deter students with disabilities from studying cybersecurity, let alone pursuing a career in the field. To help overcome this challenge, we launched the first GenCyber camp specifically developed and instructed for high school students with VIB in summer 2019. We created a unique learning environment by combining interactive instructional aids, accessible development environments, and innovative instructional strategies. With intent to show cybersecurity as a viable career option for a diverse workforce, the program outcomes from this work included a clear understanding of the GenCyber Cybersecurity Concepts, sparking interest in cybersecurity careers, and building the confidence to pursue those careers. This material is based upon work supported by the National Security Agency and National Science Foundation through the GenCyber program under award number 19-AL-UAHx-UV-S1
Relational Concurrent Refinement II: Internal Operations and Outputs
Two styles of description arise naturally in formal specification: state-based and behavioural. In state-based notations, a system is characterised by a collection of variables, and their values determine which actions may occur throughout a system history. Behavioural specifications describe the chronologies of actions -- interactions between a system and its environment. The exact nature of such interactions is captured in a variety of semantic models with corresponding notions of refinement; refinement in state based systems is based on the semantics of sequential programs and is modelled relationally. Acknowledging that these viewpoints are complementary, substantial research has gone into combining the paradigms. The purpose of this paper is to do three things. First, we survey recent results linking the relational model of refinement to the process algebraic models. Specifically, we detail how variations in the relational framework lead to relational data refinement being in correspondence with traces-divergences, singleton failures and failures-divergences refinement in a process semantics. Second, we generalise these results by providing a general flexible scheme for incorporating the two main ''erroneous'' concurrent behaviours: deadlock and divergence, into relational refinement. This is shown to subsume previous characterisations. In doing this we derive relational refinement rules for specifications containing both internal operations and outputs that corresponds to failures-divergences refinement. Third, the theory has been formally specified and verified using the interactive theorem prover KIV
Second language user support
Computer users rarely experience entirely trouble-free interaction. The natural variety ofindividuals ensures that no software systems yield constantly fluent interaction for allusers. In consequence, software designers often strive to ameliorate this situation bybuilding 'user support' into their systems. User support can take different forms but,conventionally, each aims to assist the needy end-user by means of facilities directly supporting the performance of certain operations, or through supply of information thatadvises the user on available system functionality.The present paper briefly characterises a range of user support facilities before describingone requirement in greater detail. This aspect considers the needs of users whose mother-tongue is not English, but who are obliged to use English-based information systems. Inthis context, 'helping the user' must reasonably extend beyond mere advice on systemoperation to selective elucidation of information content. We regard this move as alogical extension of the user support concept, by seeking to address specific interactionneeds in a target user population. An example of this approach is described through aninformation system, in the domain of civil engineering, for native Chinese speakers ofEnglish
Sequence and functional analyses of Haemophilus spp. genomic islands
Comparative analysis of genomic islands of Haemophilus species shows that they are co-evolving as semi-autonomous genomes within the host genome
High Energy Photoproduction
The study of photoproduction reactions has gained a unique opportunity with
the HERA data. The high center of mass energy allows to carry out quantitative
tests of QCD, to explore the substructure of both the photon and the proton and
to shed new light on soft and diffractive processes. In this report we review
the HERA results, comparing them with the reach of fixed target photoproduction
experiments and complementary measurements from and hadron colliders.Comment: 100 pages including 53 figures. To be published in the "Rivista del
Nuovo Cimento
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