<p>Multi Time period Gasoline blending is an example of multipurpose production system that is designed to produce multiple products by switching from one product to another. Various factors such as demand for gasoline, availability of supply component, and blend recipes vary with time. Task of the gasoline blender is to decide how much of each product to produce at what point in time (lot sizing) and what should be the blend recipe in order to minimize overall cost (optimize the blend recipe) . The production plans need to account for set-up times between blends and to minimize switching between different product blends. Traditional optimization techniques provide a single optimal solution. This research is using evolutionary optimization algorithm called differential evolution to identify multiple solutions t hat all have the same total cost but offer the blend planner multiple choices in terms of how much of a given product to blend at what point in time.</p> / Master of Applied Science (MASc)

<p>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Times} span.s1 {font: 12.0px Times} span.s2 {font: 8.0px Times} span.s3 {font: 6.0px Times}</p> <p>The Kraichnan-Leith-Batchelor (KLB) theory of statistically stationary forced homogeneous isotropic 2-D turbulence predicts the existence of two inertial ranges: an energy inertial range with an energy spectrum scaling of k⁻³ , and an enstrophy inertial range with an energy spectrum scaling of k⁻³. However, unlike the analogous Kolmogorov theory for 3-D turbulence, the scaling of the enstrophy range in 2-D turbulence seems to be Reynolds number dependent: numerical simulations have shown that as Reynolds number tends to infinity the enstrophy range of the energy spectrum converges to the KLB prediction, i.e. E ~ k⁻³.</p> <p>We develop an adjoint-equation based optimal control approach for controlling the energy spectrum of incompressible fluid flow. The equations are solved numerically by a highly accurate method. The computations are carried out on parallel computers in order to achieve a reasonable computational time.</p> <p>The results show that the time-space structure of the forcing can significantly alter the scaling of the energy spectrum over inertial ranges. This effect has been neglected in most previous numerical simulations by using a randomphase forcing. A careful analysis of the resulting forcing suggests that it is unlikely to be realized in nature, or by a simple numerical model. Therefore, we conjecture that the dual cascade is unlikely to be realizable at moderate</p> <p>Reynolds numbers without resorting to forcings that depend on the instantaneous flow structure or are not band-limited.</p> / Master of Applied Science (MASc)

<p>The single machine total weighted tardiness with release dates problem is known to be strongly NP-hard. With a new lower bounding scheme and a new upper bounding scheme, we get an efficient branch and bound algorithm. In the paper, we first introduce the history of the problem and its computational complexity. Second, the lower bounding schemes and the upper bounding schemes are described in detail. We also present all the dominance rules used in the branch and bound algorithm to solve the problem.</p> <p>In the dominance rules part, we describe the labeling scheme and suggest a data structure for a dominance rule.</p> <p>Finally, we implement the branch and bound algorithm in C++ for the problem with all the techniques introduced above. We present numerical results produced by the program. Using the same instance generating scheme and the test instances from Dr. Jouglet, our results show that this branch and bound method outperforms the previous approaches specialized for the problem.</p> / Master of Science (MS)

<p>This thesis presents a new linear programming approach for re-optimizing a intensity modulated radiation therapy (IMRT) treatment plan, in order to compensate for inter-fraction tissue deformations. Different formulations of the problem involve different constraints, but a common constraint that is difficult to handle mathematically is the constraint that the dose be deliverable using a small number of multi-leaf collimator positions. MLC leaves are tungsten alloy attenuators which can be moved in and out to shape of the radiation aperture. Since leaves are solid, photon fluence profiles will follow a staircase function and this constraint is not convex, and difficult to formulate. In this thesis, we propose a relaxation of this constraint to the `1-norm of the differences between adjacent radiation fluxes. With the appropriate bound, this constraint encourages the dose to be deliverable with a series of shrinking or growing openings between the leaves. Such a solution can be made realizable by rounding, which is beyond the scope of this thesis. This approach has been tested on an anonymized prostate cancer treatment plan with simulated deformations. Without rounding, solutions were obtained in five of nine cases, in less than 4 to 5 seconds of computation on a NEOS server. Solved cases demonstrated excellent target coverage (minimum dose in the target was 95% of the prescribed dose) and organ sparing (mean dose in normal tissues was below 25% of the prescribed dose).</p> / Master of Science (MSc)

<p>A short survey of recent developments in sparse matrix techniques is presented in this project. One of the problems in this area is concerned with bandwidth reduction. Several algorithms for finding symmetric row and column permutations for a given sparse symmetric matrix, such that the resulting matrix has minimum bandwidth, are discussed. A few modified algorithms yielding a better bandwidth reduction are also presented. Six well known Example problems are utilized to illustrate the work.</p> / Master of Science (MS)

<p>CYSDEM is a new FORTRAN based simulation language. It is used to simulate business information systems. The main feature of CYSDEM is that it concentrates on delays and distortions, to which information in actual systems is subjected to. Therefore, CYSDEM allows a more realistic representation of the movement of data within an information system.</p> <p>CYSDEM is based on a schematic representation of the information system under consideration, called the CYBERSTRUCTURE. The CYBERSTRUCTURE is constructed by the user. It helps the user in identifying relevant information.</p> <p>Any new computer language, requires careful verification and complete documentation. This report contains an introduction to simulation and a user's guide. Partial verification of CYSDEM was performed distribution system from Forrester's "Industrial Dynamics". The example is explained and the results are included in this report.</p> / Master of Science (MS)

<p>An algorithm is developed for discrete optimization of zero-one resource allocation problems. A single constraint problem is first formulated in dynamic programming. This formulation then undergoes a number of modifications to develop the algorithm. This algorithm leads to a significant reduction in computational requirements as compared to the dynamic programming method. Three theorems and several lemmas are proved which are central in making the algorithm efficient. Different relevant features are included in the study to extend the algorithm to solve problems with more than one constraint.</p> / Master of Science (MS)

<p>Different methods have been designed to solve systems of ordinary differential equations which avoid the restriction on step size imposed by the stability requirements alone and may be severe when the conventional numerical methods are used in solving stiff systems. This area requires further study which will lead to the development of new methods which are suitable for solving stiff equations and at the same time have high order of accuracy.</p> <p>In this investigation, classes of multistep formulas using high derivations are studied and searched for the existence of high order stiffly stable formulas, and of better stability region formulas. Stiffly stable formulas of order as to 14 were found in this search and better stability regions have been obtained by varying the choice of arbitrary coefficients to control the stability characteristics.</p> / Master of Science (MS)

<p>A survey of error detection and error recovery in simple precedence parsers is given, and in particular the error detection of Leinius, and the error recovery of Rhodes are described. An implementation of a system which generates error recovering simple precendence parsers is presented. The system divides into two subsystems, a constructor, and a skeletal parser. The grammar of the simple precedence language (L) for which a parser is required is used as input to the constructor. The constructor processes the grammar, and produces data used to prime the skeletal parser such that it can parse a sentence of L (or, an L program). The skeletal parser includes error detection based on the work of Leinius, and error recovery based on the work of Rhodes.</p> / Master of Engineering (ME)

<p>This report contains a description of the programming language PL/2100, which is a procedure oriented, block structured language with an extensive set of operators, including arithmetic, relational, logical, bit manipulation and shift operators. It is designed for writing PL/2100 programs that conform to the standard of structured programming and for efficiently expressing and implementing algorithms written in it.</p> <p>This report, also, contains a description of the one-pass working compiler (HPCOM) (for PL/2100) written for the HP/2100A minicomputer.</p> / Master of Science (MS)