5,648 research outputs found
Damping of MHD turbulence in partially ionized plasma: implications for cosmic ray propagation
We study the damping from neutral-ion collisions of both incompressible and
compressible magnetohydrodynamic (MHD) turbulence in partially ionized medium.
We start from the linear analysis of MHD waves applying both single-fluid and
two-fluid treatments. The damping rates derived from the linear analysis are
then used in determining the damping scales of MHD turbulence. The physical
connection between the damping scale of MHD turbulence and cutoff boundary of
linear MHD waves is investigated. Our analytical results are shown to be
applicable in a variety of partially ionized interstellar medium (ISM) phases
and solar chromosphere. As a significant astrophysical utility, we introduce
damping effects to propagation of cosmic rays in partially ionized ISM. The
important role of turbulence damping in both transit-time damping and
gyroresonance is identified.Comment: 29 pages, 16 figure
SPIDA: Abstracting and generalizing layout design cases
Abstraction and generalization of layout design cases generate new knowledge that is more widely applicable to use than specific design cases. The abstraction and generalization of design cases into hierarchical levels of abstractions provide the designer with the flexibility to apply any level of abstract and generalized knowledge for a new layout design problem. Existing case-based layout learning (CBLL) systems abstract and generalize cases into single levels of abstractions, but not into a hierarchy. In this paper, we propose a new approach, termed customized viewpoint - spatial (CV-S), which supports the generalization and abstraction of spatial layouts into hierarchies along with a supporting system, SPIDA (SPatial Intelligent Design Assistant)
Learning for design reuse
Over the past decade 'design assistance', i.e. where the computer is viewed as an Intelligent Design Assistant (IDA) [MacCallum-etal85], has emerged in knowledge based design support and has formed the basic research strategy for the CAD Centre, University of Strathclyde, since the mid-80s. Within this philosophy, an IDA would act as a colleague to a designer, providing guidance, learning from past design experiences, carrying out semi and fully automated tasks, explaining its reasoning and in essence complementing the designer's own natural skills, and thus leaving the ultimate decision making, control and responsibility with the designer
Demi Ran, Nan, Anna Rimed
Although end-to-end-palindromic verse that is also rhyming and metrical was pioneered by J.A. Lindon and Howard Bergerson more than three decades ago, very long examples of the form have hitherto occurred only in a short story by George Marvill. Such compositions are not, however, infeasible in reality; the one that follows, in fact, is about twice as long as the longest such effort imagined by Marvill. More challenging than lengthiness in this verse is sensibility, which is courted here mainly at the quatrain level
AI EDAM special issue: advances in implemented shape grammars: solutions and applications
This paper introduces the special issue “Advances in Implemented Shape Grammars: Solutions and Applications” and frames the topic of computer implementations of shape grammars, both with a theoretical and an applied focus. This special issue focuses on the current state of the art regarding computer implementations of shape grammars and brings a discussion about how those systems can evolve in the coming years so that they can be used in real life design scenarios. This paper presents a brief state of the art of shape grammars implementation and an overview of the papers included in the current special issue categorized under technical design, interpreters and interface design, and uses cases. The paper ends with a comprehensive outlook into the future of shape grammars implementations.info:eu-repo/semantics/acceptedVersio
Vehicle-to-Grid and ancillary services:a profitability analysis under uncertainty
The rapid and massive diffusion of electric vehicles poses new challenges to
the electric system, which must be able to supply these new loads, but at the
same time opens up new opportunities thanks to the possible provision of
ancillary services. Indeed, in the so-called Vehicle-to-Grid (V2G) set-up, the
charging power can be modulated throughout the day so that a fleet of vehicles
can absorb an excess of power from the grid or provide extra power during a
shortage.To this end, many works in the literature focus on the optimization of
each vehicle daily charging profiles to offer the requested ancillary services
while guaranteeing a charged battery for each vehicle at the end of the day.
However, the size of the economic benefits related to the provision of
ancillary services varies significantly with the modeling approaches, different
assumptions, and considered scenarios. In this paper we propose a profitability
analysis with reference to a recently proposed framework for V2G optimal
operation in presence of uncertainty. We provide necessary and sufficient
conditions for profitability in a simplified case and we show via simulation
that they also hold for the general case.Comment: Accepted by IFAC for publication under a Creative Commons Licence
CC-BY-NC-N
A foundation for machine learning in design
This paper presents a formalism for considering the issues of learning in design. A foundation for machine learning in design (MLinD) is defined so as to provide answers to basic questions on learning in design, such as, "What types of knowledge can be learnt?", "How does learning occur?", and "When does learning occur?". Five main elements of MLinD are presented as the input knowledge, knowledge transformers, output knowledge, goals/reasons for learning, and learning triggers. Using this foundation, published systems in MLinD were reviewed. The systematic review presents a basis for validating the presented foundation. The paper concludes that there is considerable work to be carried out in order to fully formalize the foundation of MLinD
Realising intelligent virtual design
This paper presents a vision and focus for the CAD Centre research: the Intelligent Design Assistant (IDA). The vision is based upon the assumption that the human and computer can operate symbiotically, with the computer providing support for the human within the design process. Recently however the focus has been towards the development of integrated design platforms that provide general support irrespective of the domain, to a number of distributed collaborative designers. This is illustrated within the successfully completed Virtual Reality Ship (VRS) virtual platform, and the challenges are discussed further within the NECTISE, SAFEDOR and VIRTUE projects
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