1,191 research outputs found
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Ideas for the Arcturus personal workstation
In order to achieve more effective use of interpersonal collaboration, management lifecycle activities, and dynamic retrieval of as well as for ordinary programming chores, it may be useful to take a fresh look at the devices we use to help us conduct our transactions with computers.This paper presents some new ideas for using large flatscreen displays and dedicated computers as personal workstations
Initial thoughts on rapid prototyping techniques
This paper sets some context, raises issues, and provides our initial thinking on the characteristics of effective rapid prototyping techniques.After discussing the role rapid prototyping techniques can play in the software lifecycle, the paper looks at possible technical approaches including: heavily parameterized models, reusable software, rapid prototyping languages, prefabrication techniques for system generation, and reconfigurable test harnesses.The paper concludes that a multi-faceted approach to rapid prototyping techniques is needed if we are to address a broad range of applications successfully -- no single technical approach suffices for all potentially desirable applications
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Steps to an advanced Ada programming environment
Conceptual simplicity, tight coupling of tools, and effective support of host-target software development will characterize advanced Ada programming support environments. Several important principles have been demonstrated in the Arcturus system, including template-assisted Ada editing, command completion using Ada as a command language, and combining the advantages of interpretation and compliation. Other principles, relating to analysis, testing, and debugging of concurrent Ada programs, have appeared in other contexts. This paper discusses several of these topics, considers how they can be integrated, and argues for their inclusion in an environment appropriate for software development in the late 1980's
Time for Geography to Catch up with the World
This article makes the case that the subject of geography needs to change if we do not want another generation of students to leave school with an outdated view of the world (Rosling et al, 2018). Firstly, we need to ensure that resources and teaching do not present a binary view of developed versus developing countries, as is the case with some exam specifications. I call for the usage of more precise language to describe the bulk of countries that sit between low and high-income countries. Teachers are encouraged to make use of Rosling's four income levels as a graduated conceptual framework to help students understand the range of countries and living conditions experienced. Secondly, development theories need to transcend reductionist and diminished notions of development (such as the Millennium Development Goals) and include a deeper idea of progress - one that encompasses cultural growth, economic and political transformation and affords nations the freedom to chart their own paths
What to Teach? Conceptualising a Geography Curriculum
Starting from the premise that a curriculum must be about knowledge, this article notes the marginalisation of disciplinary knowledge in the Anglo-American school curriculum in recent decades and how contemporary approaches to knowledge (constructivism, instrumentalism and neo-conservatism) are deficient some respect. Instead, the theory of social realism is proposed as a better way to understand the significance of disciplinary knowledge to the education of children and how it can be re-contextualised in the school curriculum. Social realism takes a sociological and epistemological approach to knowledge, moving beyond the positivist/constructivist divide. Geography’s epistemology is examined as comprising systematic geography (propositional knowledge), regional/place-based geography (contextual knowledge) and methods (procedural knowledge), and the relations between each explored. Inducting students into geography depends upon a foundational understanding of all three types of knowledge. Therefore, a robust school curriculum must be constructed with all three knowledge types such that students can enter into its conceptual framework and ways of thinking. Finally, the use of knowledge types in geography curriculum and assessment documents in the UK is discussed
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A preliminary philosophy for ARCTURUS : an advanced highly-integrated programming environment
At Irvine, we are currently in the initial stages of designing a programming environment, called Arcturus. This paper is a report of work in progress giving our preliminary philosophy and expressing preliminary thoughts on an initial Arcturus design.Arcturus is an advanced, highly-integrated programming environment intended for use in the late 1980s. We assume that programmers will each be equipped with large flat-screen displays driven by powerful desk-top computers linked into local networks by high band-width channels, and that shared central resources such as archival databases and multifont printing systems will be available.Arcturus is aimed at "programming in the large", that is, programming by many people, on large programs, with maintenance lifetimes of many years. In such a user setting, problems of management, documentation, training, testing, version control, diagnosis, and debugging must be solved effectively by people who, for the most part, are not authors or designers of the original system.Some preliminary design concepts that Arcturus supports are as follows:(1) Arcturus supports a "rapid prototyping" language -- a very high level, strongly extensible language useful for rapid construction of working prototypes of systems (emphasizing cheap, rapid construction at the expense of running efficiency and polish).(2) Arcturus supports refinement of these prototype programs, or protoprograms, for short, into programs written in program design languages (or PDLs) , which express designs. PDL programs are ultimately refined into concrete, detailed, optimized programs expressed in an implementation language.(3) Arcturus supports a computer-based form of program documentation in which program forms at various levels of abstraction can have attribute/value pairs attached to any of their granules (granules being well-formed program units of any size such as constants, variables, operators, expressions, statements, blocks, and modules) and in which the attributes may be selectively viewed and queried to suit the needs of different audiences.(4) The notion of attribute/value attachment to granules of program forms also supplies the principal mechanism for promoting a high degree of environment integration. By attaching to program granules such attributes as clocks, counters, units of programmer and system resources spent, version descriptions, access controls, descriptions of tests passed, task schedule data, computer sizing estimates, and so on, smooth integration between the activities of designers, managers, testers, maintainers, programmers, and documenters can be achieved, and environment tools can cooperate with each other conveniently.(5) Arcturus supports an advanced programmer's workstation, an interactive programmer's notebook, and extensive software management support tools.In the framework of the Arcturus effort, we have attempted to rethink afresh issues of epistemology related to the programming process that impact documentation, fault diagnosis, maintenance, training, and software upgrade, so that the design of Arcturus will reflect the relationships between the different kinds of expertise that are required in the programming process. We are also attempting to formulate theories of documentation, debugging, and maintenance to guide the development of computer-based support capabilities that assist in the performance of these activities.In this context, this paper contains preliminary, tentative expositions of background philosophy and rationale that guide our present thinking about Arcturus
The role of bacterial protein tyrosine phosphatases in the regulation of the biosynthesis of secreted polysaccharides
SIGNIFICANCE: Tyrosine phosphorylation and associated protein tyrosine phosphatases are gaining prominence as critical mechanisms in the regulation of fundamental processes in a wide variety of bacteria. In particular, these phosphatases have been associated with the control of the biosynthesis of capsular polysaccharides and extracellular polysaccharides, critically important virulence factors for bacteria.RECENT ADVANCES: Deletion and over-expression of the phosphatases result in altered polysaccharide biosynthesis in a range of bacteria. The recent structures of associated auto-phosphorylating tyrosine kinases has suggested that the phosphatases may be critical for the cycling of the kinases between monomers and higher order oligomers. CRITICAL ISSUES: Additional substrates of the phosphatases apart from cognate kinases are currently being identified. These are likely to be critical to our understanding of the mechanism by which polysaccharide biosynthesis is regulated. FUTURE DIRECTIONS: Ultimately, these protein tyrosine phosphatases are an attractive target for the development of novel anti-microbials. This is particularly the case for the polymerase and histidinol phosphatase family, which are predominantly found in bacteria. Furthermore, the determination of bacterial tyrosine phosphoproteomes will likely help to uncover the fundamental roles, mechanism and critical importance of these phosphatases in a wide range of bacteria.Alistair James Standish and Renato Moron
How the orbital period of a test particle is modified by the Dvali-Gabadadze-Porrati gravity?
In addition to the pericentre \omega, the mean anomaly M and, thus, the mean
longitude \lambda, also the orbital period Pb and the mean motion of a test
particle are modified by the Dvali-Gabadadze-Porrati gravity. While the
correction to Pb depends on the mass of the central body and on the geometrical
features of the orbital motion around it, the correction to is independent
of them, up to terms of second order in the eccentricity . The latter one
amounts to about 2\times 10^-3 arcseconds per century. The present-day accuracy
in determining the mean motions of the inner planets of the Solar System from
radar ranging and differential Very Long Baseline Interferometry is
10^-2-5\times 10^-3 arcseconds per century, but it should be improved in the
near future when the data from the spacecraft to Mercury and Venus will be
available.Comment: LaTex, 7 pages, 13 references, no tables, no figures. Section 2.3
added. To appear in JCA
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