3,688 research outputs found
A thread calculus with molecular dynamics
We present a theory of threads, interleaving of threads, and interaction
between threads and services with features of molecular dynamics, a model of
computation that bears on computations in which dynamic data structures are
involved. Threads can interact with services of which the states consist of
structured data objects and computations take place by means of actions which
may change the structure of the data objects. The features introduced include
restriction of the scope of names used in threads to refer to data objects.
Because that feature makes it troublesome to provide a model based on
structural operational semantics and bisimulation, we construct a projective
limit model for the theory.Comment: 47 pages; examples and results added, phrasing improved, references
replace
Programming an interpreter using molecular dynamics
PGA (ProGram Algebra) is an algebra of programs which concerns programs in
their simplest form: sequences of instructions. Molecular dynamics is a simple
model of computation developed in the setting of PGA, which bears on the use of
dynamic data structures in programming. We consider the programming of an
interpreter for a program notation that is close to existing assembly languages
using PGA with the primitives of molecular dynamics as basic instructions. It
happens that, although primarily meant for explaining programming language
features relating to the use of dynamic data structures, the collection of
primitives of molecular dynamics in itself is suited to our programming wants.Comment: 27 page
Real-time optical micro-manipulation using optimized holograms generated on the GPU
Holographic optical tweezers allow the three dimensional, dynamic, multipoint
manipulation of micron sized dielectric objects. Exploiting the massive
parallel architecture of modern GPUs we can generate highly optimized holograms
at video frame rate allowing the interactive micro-manipulation of 3D
structures.Comment: 13 pages, 8 figure
Data linkage algebra, data linkage dynamics, and priority rewriting
We introduce an algebra of data linkages. Data linkages are intended for
modelling the states of computations in which dynamic data structures are
involved. We present a simple model of computation in which states of
computations are modelled as data linkages and state changes take place by
means of certain actions. We describe the state changes and replies that result
from performing those actions by means of a term rewriting system with rule
priorities. The model in question is an upgrade of molecular dynamics. The
upgrading is mainly concerned with the features to deal with values and the
features to reclaim garbage.Comment: 48 pages, typos corrected, phrasing improved, definition of services
replaced; presentation improved; presentation improved and appendix adde
NEXUS/Physics: An interdisciplinary repurposing of physics for biologists
In response to increasing calls for the reform of the undergraduate science
curriculum for life science majors and pre-medical students (Bio2010,
Scientific Foundations for Future Physicians, Vision & Change), an
interdisciplinary team has created NEXUS/Physics: a repurposing of an
introductory physics curriculum for the life sciences. The curriculum interacts
strongly and supportively with introductory biology and chemistry courses taken
by life sciences students, with the goal of helping students build general,
multi-discipline scientific competencies. In order to do this, our two-semester
NEXUS/Physics course sequence is positioned as a second year course so students
will have had some exposure to basic concepts in biology and chemistry.
NEXUS/Physics stresses interdisciplinary examples and the content differs
markedly from traditional introductory physics to facilitate this. It extends
the discussion of energy to include interatomic potentials and chemical
reactions, the discussion of thermodynamics to include enthalpy and Gibbs free
energy, and includes a serious discussion of random vs. coherent motion
including diffusion. The development of instructional materials is coordinated
with careful education research. Both the new content and the results of the
research are described in a series of papers for which this paper serves as an
overview and context.Comment: 12 page
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