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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Topics in functions with symmetry

Baines, Clare Elizabeth January 2000 (has links)
No description available.

Group-Theoretic Study of the Regular Polyhedra

Snyder, Walter A. January 1942 (has links)
No description available.

Group-Theoretic Study of the Regular Polyhedra

Snyder, Walter A. January 1942 (has links)
No description available.

Polyhedral structure of the K-median problem

Zhao, Wenhui 19 September 2007 (has links)
No description available.

Polyhedral approaches to solving nonconvex quadratic programs

Vandenbussche, Dieter 05 1900 (has links)
No description available.

Computing Fréchet distance of two paths on a convex polyhedron /

Yi, Jiehua, January 1900 (has links)
Thesis (M.C.S.)--Carleton University, 2004. / Includes bibliographical references (p. 70-72). Also available in electronic format on the Internet.

Cyanate Ester, Epoxy And Epoxy/Cyanate Ester Matrix Polyhedral Oligomeric Silsesquioxane Nanocomposites

Liang, Kaiwen 10 December 2005 (has links)
Cyanate ester (PT-15, Lonza Corp) composites containing the inorganic-organic hybrid polyhedral oligomeric silsesquioxanes (POSS), octaaminophenyl(T8)POSS (C6H4NH2)8(SiO1.5)8, cyanopropylheptacyclopentyl(T8)POSS, (C5H9)7(SiO1.5)8(CH2) 3CN or TriSilanolPhenylPOSS (C42H38O12Si7), were synthesized respectively. These PT-15/POSS composites were characterized by FT-IR, X-ray diffraction (XRD), small-angle neutron scattering (SANS), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (X-EDS), transmission electron microscopy (TEM), dynamic mechanical thermal analysis (DMTA) and three-point bending flexural tests. XRD, TEM and IR data are all consistent with molecular dispersion of octaaminophenyl(T8)POSS and TriSilanolPhenylPOSS due to the chemical bonding of the POSS macromer into the continuous cyanate ester network phase. In contrast to octaaminophenyl(T8) POSS and TriSilanolPhenylPOSS, cyanopropylheptacyclopentyl (T8)POSS has a low solubility in PT-15 and does not react with the resin before or during the cure. The TriSilanolPhenylPOSS (C42H38O12Si7) was incorporated into the aliphatic epoxy (Epoxy 9000, Clearstream Products, Inc.) in 99/1, 97/3, 95/5, 90/10 and 85/15 w/w ratios and cured. This same epoxy resin was also blended with an equal weight (50/50 w/w) of cyanate ester resin (PT-15, Lonza Corp) and TriSilanolPhenylPOSS was added in resin/POSS weight ratios of 99/1, 97/3, 95/5, 90/10 and 85/15 and cured. Both sets of composites were characterized by FT-IR, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (X-EDS), dynamic mechanical thermal analysis (DMTA) and three-point bending flexural tests. TriSilanolPhenyl-POSS was first thoroughly dispersed into the uncured liquid epoxy resin or the epoxy/PT-15 blend. XRD and X-EDS measurements after curing were consistent with partial molecular dispersion of the POSS units in the continuous matrix phase, while the remainder forms POSS aggregates. TEM and SEM show that POSS?enriched nanoparticles are present in the matrix resins of both the epoxy/POSS and epoxy-PT-15/POSS composites.

Fast Polyhedral Adaptive Conjoint Estimation

Olivier, Toubia, Duncan, Simester, John, Hauser 02 1900 (has links)
We propose and test a new adaptive conjoint analysis method that draws on recent polyhedral “interior-point” developments in mathematical programming. The method is designed to offer accurate estimates after relatively few questions in problems involving many parameters. Each respondent’s ques-tions are adapted based upon prior answers by that respondent. The method requires computer support but can operate in both Internet and off-line environments with no noticeable delay between questions. We use Monte Carlo simulations to compare the performance of the method against a broad array of relevant benchmarks. While no method dominates in all situations, polyhedral algorithms appear to hold significant potential when (a) metric profile comparisons are more accurate than the self-explicated importance measures used in benchmark methods, (b) when respondent wear out is a concern, and (c) when product development and/or marketing teams wish to screen many features quickly. We also test hybrid methods that combine polyhedral algorithms with existing conjoint analysis methods. We close with suggestions on how polyhedral methods can be used to address other marketing problems. / Sloan School of Management and the Center for Innovation in Product Development at MIT

Computational Studies On Macropolyhedral Boranes And Metallaboranes

Shameema, O 08 1900 (has links)
The analysis of nature of bonding in non-classical structures is always an intriguing area of research. Typical examples of such systems are polyhedral boranes that exhibit fascinating cluster bonding where the traditional 2-center-2-electron (2c-2e) bond model fails. This thesis involves the investigation of such polyhedral borane structures and their reactivity by employing both qualitative and quantitative tools of electronic structure theory. There is an intense current interest in the macropolyhedral boranes for their applications pharmaceuticals and materials chemistry. The mno rule had been formulated to account for the electronic requirements for the macropolyhedral structures. Though useful in explaining and designing structures, electron counting rules provide a yes or no answer; not all the molelcules having stipulated number of electrons are equally stable. We have used the concept of orbital compatibility to explain the relative energies of different macropolyhedral structural patterns such as closo-closo, closo-nido and nido-nido. One of the major problems in polyhedral boron cage chemistry has been the lack of general synthetic routes for the construction of large cage systems . With this view, we explored the mechanism of the reaction of macropolyhedron B20H16 with MeCN and similar ligands, which provide an understanding of the skeletal rearrangement that occur in macropolyhedral boranes. This can help in the design and synthesis of new macropolyhedral boranes. The early examples of metallaboranes were found to adopt structures which are analogous to that of boranes and carboranes. Hypercloso metallaboranes have closo structure with less number of electrons than required by Wades rule. We have carried out a detailed DFT analysis to explore the structure and electronic relationship of 9-12 vertex closo and hypercloso structures of both borane and metallaboranes. Calculations show that in vertex hypercloso metallaborane needs only n skeleton electron pairs rather than n+1 as suggested by Wade’s rules. Stabilization of supraicosahedral boranes with more than 12 vertices by substituting BH groups by transition metal fragments is also explored with DFT calculations. Calculations show that as the number and the size of the metal atom increases the stability of supraicosahedral and condensed supraicosahedral borane structures also increases. These studies will open up new possibilities for the development of polyhedral clusters of extraordinary size.

Generating cutting planes through inequality merging on multiple variables in knapsack problems

Bolton, Thomas Charles January 1900 (has links)
Master of Science / Industrial & Manufacturing Systems Engineering / Todd W. Easton / Integer programming is a field of mathematical optimization that has applications across a wide variety of industries and fields including business, government, health care and military. A commonly studied integer program is the knapsack problem, which has applications including project and portfolio selection, production planning, inventory problems, profit maximization applications and machine scheduling. Integer programs are computationally difficult and currently require exponential effort to solve. Adding cutting planes is a way of reducing the solving time of integer programs. These cutting planes eliminate linear relaxation space. The theoretically strongest cutting planes are facet defining inequalities. This thesis introduces a new class of cutting planes called multiple variable merging cover inequalities (MVMCI). The thesis presents the multiple variable merging cover algorithm (MVMCA), which runs in linear time and produces a valid MVMCI. Under certain conditions, an MVMCI can be shown to be a facet defining inequality. An example demonstrates these advancements and is used to prove that MVMCIs could not be identified by any existing techniques. A small computational study compares the computational impact of including MVMCIs. The study shows that finding an MVMCI is extremely fast, less than .01 seconds. Furthermore, including an MVMCI improved the solution time required by CPLEX, a commercial integer programming solver, by 6.3% on average.

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