MacSphere
http://macsphere.mcmaster.ca:8080
The MacSphere digital repository system captures, stores, indexes, preserves, and distributes digital research material.Thu, 30 Mar 2017 11:28:18 GMT2017-03-30T11:28:18ZSynthesis Method for Hierarchical Interface-Based Supervisory Control
http://hdl.handle.net/11375/21265
Title: Synthesis Method for Hierarchical Interface-Based Supervisory Control
Authors: Dai, Pengcheng
Abstract: <p> Hierarchical Interface-based Supervisory Control (HISC) decomposes a discrete-event
system (DES) into a high-level subsystem which communicates with n ≥ 1 low-level subsystems, through separate interfaces which restrict the interaction of the subsystems. It provides a set of local conditions that can be used to verify global conditions such as nonblocking and controllability. As each clause of the definition can be verified using a single subsystem, the complete system model never needs to be stored in memory, offering potentially significant savings in computational resources.</p> <p> Currently, a designer must create the supervisors for a HISC system himself, and then verify that they satisfy the HISC conditions. In this thesis, we develop a synthesis method that respects the HISC hierarchical structure. We replace the supervisor for each level by a corresponding specification DES. We then do a per level synthesis to construct for each level a maximally permissive supervisor that satisfies the corresponding HISC conditions.</p> <p> We define a set of language based fixpoint operators and show that they compute the required level-wise supremal languages. We then present algorithms that implement the fixpoint operators. We present a complexity analysis for the algorithms and show that they potentially offer significant improvement over the monolithic approach.</p> <p> A large manufacturing system example (estimated worst case state space on the order of 10^22) extended from the AIP example is discussed. A software tool for synthesis and verification of HISC systems using our approach was also developed.</p>Sat, 01 Apr 2006 00:00:00 GMThttp://hdl.handle.net/11375/212652006-04-01T00:00:00ZProperty Inference for Maple: An Application of Abstract Interpretation
http://hdl.handle.net/11375/21264
Title: Property Inference for Maple: An Application of Abstract Interpretation
Authors: Forrest, Stephen A.
Abstract: <p> We present a system for the inference of various static properties from source code
written in the Maple programming language. We make use of an abstract interpretation
framework in the design of these properties and define languages of constraints specific to our abstract domains which capture the desired static properties of the code. Finally we discuss the automated generation and solution of these constraints, describe a tool for doing
so, and present some results from applying this tool to several nontrivial test inputs.</p>Sun, 24 Sep 2017 00:00:00 GMThttp://hdl.handle.net/11375/212642017-09-24T00:00:00ZCitizen Brief: Improving Pain and Symptom Management in Cancer Care in Ontario
http://hdl.handle.net/11375/18854
Title: Citizen Brief: Improving Pain and Symptom Management in Cancer Care in Ontario
Authors: Moat, Kaelan A.
Abstract: An assessment of what is known about problems related to pain and symptom management in cancer care, options for addressing these problems, and key implementation considerations. The citizen brief was an input to a citizen panel on the topic of improving pain and symptom management in cancer care in Ontario.Thu, 01 Oct 2015 00:00:00 GMThttp://hdl.handle.net/11375/188542015-10-01T00:00:00ZSome Nice Results About Anistropic Mean Curvature Flow
http://hdl.handle.net/11375/21261
Title: Some Nice Results About Anistropic Mean Curvature Flow
Authors: Dailey-McIlrath, Adam
Abstract: <p>Imagine stretching out a rubber band on a flat surface and letting go suddenly.
Picture the way the rubber band contracts in slow motion and that
should give you a good idea of how mean curvature flow dictates the evolution
of plane curves. The more stretched out the rubber band, the faster it
snaps back. Just like the rubber band returns to it's original round shape no
matter how it is stretched, any smooth plane curve will evolve under mean
curvature flow to a circle. Suppose that you try to kink the rubber band, try
to force a sharp corner into it. As soon as you let go those kinks disappear.
Similarly a piecewise smooth curve will smooth out instantaneously under
mean curvature flow. Now suppose that you stretch out the rubber band and
put kinks in it, but instead of letting go completely, you hold those kinks in
place. The rest of the rubber band will still try to shrink back to it's original
circular shape. This is the major topic of this paper-how do piecewise
smooth curves behave under mean curvature flow if their kinks are held fast?
It turns out that the initial evolution of a curve in such a situation depends
completely on the number and precise angles of those kinks.</p> <p>One of the earliest references on mean curvature flow is a 1956 paper [15]
which explored a specific case of piecewise smooth curves evolving by mean
curvature and found that by counting the number of sides one could determine
how the enclosed area would change (Theorem 4.1). This was a surprising
result because in the smooth case, the area enclosed is always shrinking,
but by adding some sharp corners it became possible that the area would increase
initially. Little attention seems to have been paid to piecewise smooth
curves and mean curvature flow since then, with one notable exception being
a paper by L. Bronsard and F. Reitich [5] which proved that the curves
analyzed in the 1956 paper could really exist!</p> <p>The main result of this paper is Theorem 4.4 which is a generalization of the
aforementioned Theorem 4.1. The new result generalizes the original in two
ways: first it is non-specific with respect to the angles at the corners, and
second, it allows for the flow to be anisotropic; the evolution of the curve
may depend on it's orientation in the plane. Two proofs of this result are
presented. One uses ideas from the 1956 paper and is fairly intuitive. The
other proof follows the strategy of a more recent paper [10] and proves the
result as an intrinsic property of the curve. The final section of the paper
mentions some other questions and topics related to mean curvature flow
and includes a new result about the behavior of curves evolving on the unit
sphere according to a generalized version of mean curvature flow.</p>
Description: Title: Some Nice Results About Anistropic Mean Curvature Flow, Author: Amad Dailey-McIlrath, Location: ThodeFri, 01 Sep 2006 00:00:00 GMThttp://hdl.handle.net/11375/212612006-09-01T00:00:00Z