8,539 research outputs found
Demo of three ways to use a computer to assist in lab
The objective is to help the slow learner and students with a language problem, or to challenge the advanced student. Technology has advanced to the point where images generated on a computer can easily be recorded on a VCR and used as a video tutorial. This transfer can be as simple as pointing a video camera at the screen and recording the image. For more clarity and professional results, a board may be inserted into a computer which will convert the signals directly to the TV standard. Using a computer program that generates movies one can animate various principles which would normally be impossible to show or would require time-lapse photography. For example, you might show the change in shape of grains as a piece of metal is cold worked and then show the recrystallization and grain growth as heat is applied. More imaginative titles and graphics are also possible using this technique. Remedial help may also be offered via computer to those who find a specific concept difficult. A printout of specific data, details of the theory or equipment set-up can be offered. Programs are now available that will help as well as test the student in specific areas so that a Keller type approach can be used with each student to insure each knows the subject before going on to the next topic. A computer can serve as an information source and contain the microstructures, physical data and availability of each material tested in the lab. With this source present unknowns can be evaluated and various tests simulated to create a simple or complex case study lab assignment
Volterra integral equations and fractional calculus: Do neighbouring solutions intersect?
This is the author's PDF version of an article published in Journal of integral equations
and applications. The definitive version is available at rmmc.asu.edu/jie/jie.html.This journal article considers the question of whether or not the solutions to two Volterra integral equations which have the same kernel but different forcing terms may intersect at some future time
The numerical solution of fractional differential equations: Speed versus accuracy
This paper discusses the development of efficient algorithms for a certain fractional differential equation.Manchester Centre for Computational Mathematic
Distributed order equations as boundary value problems
This is a PDF version of a preprint submitted to Elsevier. The definitive version was published in Computers and mathematics with applications and is available at www.elsevier.comThis preprint discusses the existence and uniqueness of solutions and proposes a numerical method for their approximation in the case where the initial conditions are not known and, instead, some Caputo-type conditions are given away from the origin
Detachment, Futile Cycling and Nucleotide Pocket Collapse in Myosin-V Stepping
Myosin-V is a highly processive dimeric protein that walks with 36nm steps
along actin tracks, powered by coordinated ATP hydrolysis reactions in the two
myosin heads. No previous theoretical models of the myosin-V walk reproduce all
the observed trends of velocity and run-length with [ADP], [ATP] and external
forcing. In particular, a result that has eluded all theoretical studies based
upon rigorous physical chemistry is that run length decreases with both
increasing [ADP] and [ATP]. We systematically analyse which mechanisms in
existing models reproduce which experimental trends and use this information to
guide the development of models that can reproduce them all. We formulate
models as reaction networks between distinct mechanochemical states with
energetically determined transition rates. For each network architecture, we
compare predictions for velocity and run length to a subset of experimentally
measured values, and fit unknown parameters using a bespoke MCSA optimization
routine. Finally we determine which experimental trends are replicated by the
best-fit model for each architecture. Only two models capture them all: one
involving [ADP]-dependent mechanical detachment, and another including
[ADP]-dependent futile cycling and nucleotide pocket collapse. Comparing
model-predicted and experimentally observed kinetic transition rates favors the
latter.Comment: 11 pages, 5 figures, 6 table
Methods to Determine Node Centrality and Clustering in Graphs with Uncertain Structure
Much of the past work in network analysis has focused on analyzing discrete
graphs, where binary edges represent the "presence" or "absence" of a
relationship. Since traditional network measures (e.g., betweenness centrality)
utilize a discrete link structure, complex systems must be transformed to this
representation in order to investigate network properties. However, in many
domains there may be uncertainty about the relationship structure and any
uncertainty information would be lost in translation to a discrete
representation. Uncertainty may arise in domains where there is moderating link
information that cannot be easily observed, i.e., links become inactive over
time but may not be dropped or observed links may not always corresponds to a
valid relationship. In order to represent and reason with these types of
uncertainty, we move beyond the discrete graph framework and develop social
network measures based on a probabilistic graph representation. More
specifically, we develop measures of path length, betweenness centrality, and
clustering coefficient---one set based on sampling and one based on
probabilistic paths. We evaluate our methods on three real-world networks from
Enron, Facebook, and DBLP, showing that our proposed methods more accurately
capture salient effects without being susceptible to local noise, and that the
resulting analysis produces a better understanding of the graph structure and
the uncertainty resulting from its change over time.Comment: Longer version of paper appearing in Fifth International AAAI
Conference on Weblogs and Social Media. 9 pages, 4 Figure
Mixed-type functional differential equations: A numerical approach
This is a PDF version of a preprint submitted to Elsevier. The definitive version was published in Journal of computational and applied mathematics and is available at www.elsevier.comThis preprint discusses mixed-type functional equations
Fractional boundary value problems: Analysis and numerical methods
This is the author's PDF of an article published in Fractional calculus and applied analysis 2011. The original publication is available at www.springerlink.comThis journal article discusses nonlinear boundary value problems.Fundacao para a Ciencia e Tecnologi
An algorithm to detect small solutions in linear delay differential equations
This is a PDF version of a preprint submitted to Elsevier. The definitive version was published in the Journal of computational and applied mathematics and is available at www.elsevier.comThis preprint discusses an algorithm that provides a simple reliable mechanism for the detection of small solutions in linear delay differential equations.This article was submitted to the RAE2008 for the University of Chester - Applied Mathematics
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