Finite semifields and nonsingular tensors

In this article, we give an overview of the classification results in the theory of finite semifields (note that this is not intended as a survey of finite semifields including a complete state of the art (see also Remark 1.10)) and elaborate on the approach using nonsingular tensors based on Liebler (Geom Dedicata 11(4):455-464, 1981)

Manifold optimization methods for macromolecular docking

Thesis (Ph.D.)--Boston UniversityThis thesis develops efficient algorithms for local optimization problems encountered in predictive docking of biological macromolecules. Predictive docking, defined as computationally obtaining a model of the bound complex from the coordinates of the two component molecules, is one of the fundamental and challenging problems in computational structural biology. Docking methods generally search for the minima of an energy or scoring function that estimates the binding free energy or, more frequently, the interaction energy, of the two molecules. These energy functions generally have large numbers of local minima, resulting in extremely rugged energy landscapes. Therefore, independently of the algorithm used for sampling the conformational space, virtually all docking algorithms include some type of local continuous minimization of the energy function. Most state-of-the-art algorithms allow for the free movement of all atoms of the two molecules and rely on the minimization of the energy function to enforce structural constraints of the molecules. In contrast this thesis exploits the partial or complete rigidity of the molecules when defining the conformational space. As a result, the local optimization problems are formulated as optimization problems on appropriately defined manifolds. In the case of rigid docking, a novel manifold representation of rigid motions of a body is introduced that resolves many of the optimization difficulties associated with the commonly used manifold for this purposed , the so-called Special Euclidean group, SE(3). These difficulties arise from a coupling that SE(3) introduces between the rotational and translational move of the body. The new representation decouples these moves and results in a more appropriate and flexible optimization algorithm. Experimental results show that the proposed algorithm is an order of magnitude more efficient than the current state-of-the-art algorithms. The proposed manifold optimization approach is then extended to the case of flexible docking. The novel manifold representation of rigid motions is combined with the so-called internal coordinate representation of flexible moves to define a new manifold to which the original manifold optimization algorithm can be directly extended. Computational results show that the resulting optimization algorithm is substantially more efficient than energy minimization using a traditional all-atom optimization algorithm while producing solutions of comparable quality. It is shown that the application of the proposed local optimization algorithm as one of the components of a multi-stage refinement protocol for protein-protein docking contributes significantly to the refinement stage by helping to move the distribution of docking decoys closer to the corresponding bound structures. Finally, it is shown that the approach of the thesis can be substantially generalized to address the problem of minimization of a cost function that depends on the location and poses of one or more rigid bodies, or bodies that consist of rigid parts hinged together. This is a formulation used in a number of engineering applications other than molecular docking

Timing-Driven Macro Placement

Placement is an important step in the process of finding physical layouts for electronic computer chips. The basic task during placement is to arrange the building blocks of the chip, the circuits, disjointly within a given chip area. Furthermore, such positions should result in short circuit interconnections which can be routed easily and which ensure all signals arrive in time. This dissertation mostly focuses on macros, the largest circuits on a chip. In order to optimize timing characteristics during macro placement, we propose a new optimistic timing model based on geometric distance constraints. This model can be computed and evaluated efficiently in order to predict timing traits accurately in practice. Packing rectangles disjointly remains strongly NP-hard under slack maximization in our timing model. Despite of this we develop an exact, linear time algorithm for special cases. The proposed timing model is incorporated into BonnMacro, the macro placement component of the BonnTools physical design optimization suite developed at the Research Institute for Discrete Mathematics. Using efficient formulations as mixed-integer programs we can legalize macros locally while optimizing timing. This results in the first timing-aware macro placement tool. In addition, we provide multiple enhancements for the partitioning-based standard circuit placement algorithm BonnPlace. We find a model of partitioning as minimum-cost flow problem that is provably as small as possible using which we can avoid running time intensive instances. Moreover we propose the new global placement flow Self-Stabilizing BonnPlace. This approach combines BonnPlace with a force-directed placement framework. It provides the flexibility to optimize the two involved objectives, routability and timing, directly during placement. The performance of our placement tools is confirmed on a large variety of academic benchmarks as well as real-world designs provided by our industrial partner IBM. We reduce running time of partitioning significantly and demonstrate that Self-Stabilizing BonnPlace finds easily routable placements for challenging designs – even when simultaneously optimizing timing objectives. BonnMacro and Self-Stabilizing BonnPlace can be combined to the first timing-driven mixed-size placement flow. This combination often finds placements with competitive timing traits and even outperforms solutions that have been determined manually by experienced designers

Hydrodynamic Design Structural Analysis and Optimization of Marine Propeller Blade

There are many problems to be addressed in the design of marine propeller blade. Among these, the foremost is the efficiency of the propeller. The design of ship propeller involves a number of competing variables including the rake, pitch distribution and blade surface area. The propeller design also aims at achieving high propulsive efficiency at low levels of noise and vibration with reduced cavitation. All of these factors affect vessels top speed, fuel efficiency, and handling. A thorough understanding of propeller dynamics is necessary to design an efficient and reliable propeller blade. Numerical models are commonly used for the dynamic characterization of propeller blades, due to the difficulties of performing full-scale measurements. In contrast, the current research focuses on the hydrodynamic design of a Wageningen B-series four bladed propeller used for marine applications. The analyses presented in this thesis have been divided into three main phases. In the first phase, the hydrodynamic design of Wageningen B-series four bladed marine propeller is carried out, to determine the suitability and applicability of propeller blade for underwater conditions is done by 1) Open water characteristics determination, 2) Cavitation inception point determination for metallic propeller blade. The prevailing conditions applied for evaluating these hydrodynamic characteristics are taken from reference and validated with standard series data. In the second phase of the research, Strength determination of both metallic and composite propeller (E-glass epoxy material) are determined in terms of its stress and free vibration characteristics. Numerical analyses are carried out using suitable numerical methods for the deflection calculations and to determine the stress distribution in the blade foot and the blades at operational load conditions. A modal vibrational analysis for prediction of vibration response was also conducted for the blade, because the composite blades tend to deform more than that of metallic one and the deformation can be used in the analysis of hydrodynamic performance. Experiments are performed to compare the results with that obtained from the numerical analysis. In the last phase Structural optimization of composite propeller was done both for non-hybrid and hybrid composites, (comprises a series of combination of Glass fiber reinforced plastic and Carbon reinforced plastic GFRP & CFRP), using the mid-surface as reference and meshed with shell elements to find out the optimum ply stacking sequence for Interlaminar shear stresses and deflection minimization and operational efficiency improvement of composite propeller blade compared to metallic one. The obtained final stacking sequence of the composite propeller was evaluated by varying the number of layers in steps the Interlaminar shear stresses are calculated, and the results are compared with the metallic propeller. The following basic data are used for analysis and the main points performed during the works are given below. 1. The open water characteristics are predicted computationally on the basis of a validated small sized propeller where the delivered power (PD), the advanced coefficient (Vga), and the propeller revolution (N) are known. 2. The cavitation inception point for the metallic propeller is determined which can be used for structural analysis. 3. The Aluminum propeller blade is replaced with E-glass epoxy material blade and structural analyses for both the materials are carried out. 4. An optimum stacking sequence for composite material blade varied with non-hybrid and hybrid materials are determined. 5. Finally, a comparison has been made with metallic and composite materials in terms of their strength behavior

Hardward and algorithm architectures for real-time additive synthesis

Additive synthesis is a fundamental computer music synthesis paradigm tracing its origins to the work of Fourier and Helmholtz. Rudimentary implementation linearly combines harmonic sinusoids (or partials) to generate tones whose perceived timbral characteristics are a strong function of the partial amplitude spectrum. Having evolved over time, additive synthesis describes a collection of algorithms each characterised by the time-varying linear combination of basis components to generate temporal evolution of timbre. Basis components include exactly harmonic partials, inharmonic partials with time-varying frequency or non-sinusoidal waveforms each with distinct spectral characteristics. Additive synthesis of polyphonic musical instrument tones requires a large number of independently controlled partials incurring a large computational overhead whose investigation and reduction is a key motivator for this work. The thesis begins with a review of prevalent synthesis techniques setting additive synthesis in context and introducing the spectrum modelling paradigm which provides baseline spectral data to the additive synthesis process obtained from the analysis of natural sounds. We proceed to investigate recursive and phase accumulating digital sinusoidal oscillator algorithms, defining specific metrics to quantify relative performance. The concepts of phase accumulation, table lookup phase-amplitude mapping and interpolated fractional addressing are introduced and developed and shown to underpin an additive synthesis subclass - wavetable lookup synthesis (WLS). WLS performance is simulated against specific metrics and parameter conditions peculiar to computer music requirements. We conclude by presenting processing architectures which accelerate computational throughput of specific WLS operations and the sinusoidal additive synthesis model. In particular, we introduce and investigate the concept of phase domain processing and present several “pipeline friendly” arithmetic architectures using this technique which implement the additive synthesis of sinusoidal partials

Structural and economic aspects of the use of semi-rigid joints in steel frames

This thesis reports on five main areas as follows: 1. Braced steel frames designed for semi-continuous construction were studied to determine savings in both cost and weight. Various frame parameters such as the number of bays, use of grade S355 steel, beam spans, types of connection, and selection of beam size were investigated. The investigation confirmed that semicontinuous construction contributes to worthwhile percentage savings on both cost and weight. 2. Analysis and design of steel unbraced frames bending on both axes were performed with emphasis on stability and deflection checks. Rules are proposed to improve the stability and stiffness. For connections to the minor axis, a proposed joint detail is presented. The performance of the frames was checked for collapse load level at ULS; deflection limits at SLS were also checked; in both cases using first and second order analysis. The investigation demonstrated that the frames should be restricted to less than four storeys. 3. A study on minor axis joints was carried out for flush end plate connections connected to the column web. Previous experimental results of moment and stiffness were compared with predicted values. Moment values were predicted using Gomes' formulae. The stiffness due to the column web was predicted using finite element analysis. The results showed good agreement between experimental and predicted values. The study on the connections was extended to their suitability in steel frames bending about the minor axis; the investigation confirmed that the connections were not suitable for unbraced wind-moment frames. An equation for prediction of initial stiffness was nevertheless established for the connection. 4. Steel frames with composite beams designed for minimum wind combined with maximum gravity load were studied for their performance, taking into account cracking along the beams. The investigation showed that the frames meet the requirements of deflection and sustain a load level of 1.0 for ULS. For frames studied for maximum wind combined with minimum gravity load, the moment capacity of the joints governed the design which resulted in a deeper beam section. 5. Seven tests were carried out for a new type of shear connector system installed by compressed air. The aim of the tests was to study the shear capacity and ductility of the studs. The tests showed that the pins fail due to fracture and the stud systems needs some improvements to increase the key structural properties

New Development of Neutrosophic Probability, Neutrosophic Statistics, Neutrosophic Algebraic Structures, and Neutrosophic & Plithogenic Optimizations

This Special Issue puts forward for discussion state-of-the-art papers on new topics related to neutrosophic theories, such as neutrosophic algebraic structures, neutrosophic triplet algebraic structures, neutrosophic extended triplet algebraic structures, neutrosophic algebraic hyperstructures, neutrosophic triplet algebraic hyperstructures, neutrosophic n-ary algebraic structures, neutrosophic n-ary algebraic hyperstructures, refined neutrosophic algebraic structures, refined neutrosophic algebraic hyperstructures, quadruple neutrosophic algebraic structures, refined quadruple neutrosophic algebraic structures, neutrosophic image processing, neutrosophic image classification, neutrosophic computer vision, neutrosophic machine learning, neutrosophic artificial intelligence, neutrosophic data analytics, neutrosophic deep learning, neutrosophic symmetry, and their applications in the real world. This book leads to the further advancement of the neutrosophic and plithogenic theories of NeutroAlgebra and AntiAlgebra, NeutroGeometry and AntiGeometry, Neutrosophic n-SuperHyperGraph (the most general form of graph of today), Neutrosophic Statistics, Plithogenic Logic as a generalization of MultiVariate Logic, Plithogenic Probability and Plithogenic Statistics as a generalization of MultiVariate Probability and Statistics, respectively, and presents their countless applications in our every-day world

Bibliography of Lewis Research Center technical publications announced in 1977

This compilation of abstracts describes and indexes over 780 technical reports resulting from the scientific and engineering work performed and managed by the Lewis Research Center in 1977. All the publications were announced in the 1977 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Documents cited include research reports, journal articles, conference presentations, patents and patent applications, and theses

New Development of Neutrosophic Probability, Neutrosophic Statistics, Neutrosophic Algebraic Structures, and Neutrosophic Plithogenic Optimizations

This volume presents state-of-the-art papers on new topics related to neutrosophic theories, such as neutrosophic algebraic structures, neutrosophic triplet algebraic structures, neutrosophic extended triplet algebraic structures, neutrosophic algebraic hyperstructures, neutrosophic triplet algebraic hyperstructures, neutrosophic n-ary algebraic structures, neutrosophic n-ary algebraic hyperstructures, refined neutrosophic algebraic structures, refined neutrosophic algebraic hyperstructures, quadruple neutrosophic algebraic structures, refined quadruple neutrosophic algebraic structures, neutrosophic image processing, neutrosophic image classification, neutrosophic computer vision, neutrosophic machine learning, neutrosophic artificial intelligence, neutrosophic data analytics, neutrosophic deep learning, and neutrosophic symmetry, as well as their applications in the real world