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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Enabling Optimizations Through Demodularization, Blake Dennis Johnson
Enabling Optimizations Through Demodularization, Blake Dennis Johnson
Theses and Dissertations
Programmers want to write modular programs to increase maintainability and create abstractions, but modularity hampers optimizations, especially when modules are compiled separately or written in different languages. In languages with syntactic extension capabilities, each module in a program can be written in a separate language, and the module system must ensure that the modules interoperate correctly. In Racket, the module system ensures this by separating module code into phases for runtime and compile-time and allowing phased imports and exports inside modules. We present an algorithm, called demodularization, that combines all executable code from a phased modular program into a single …
Optimized Simulation Of Granular Materials, Seth R. Holladay
Optimized Simulation Of Granular Materials, Seth R. Holladay
Theses and Dissertations
Visual effects for film and animation often require simulated granular materials, such as sand, wheat, or dirt, to meet a director's needs. Simulating granular materials can be time consuming, in both computation and labor, as these particulate materials have complex behavior and an enormous amount of small-scale detail. Furthermore, a single cubic meter of granular material, where each grain is a cubic millimeter, would contain a billion granules, and simulating all such interacting granules would take an impractical amount of time for productions. This calls for a simplified model for granular materials that retains high surface detail and granular behavior …
Performance Evaluation Of Optimal Rate Allocation Models For Wireless Networks, Ryan Michael Padilla
Performance Evaluation Of Optimal Rate Allocation Models For Wireless Networks, Ryan Michael Padilla
Theses and Dissertations
Convex programming is used in wireless networks to optimize the sending or receiving rates of links or flows in a network. This kind of optimization problem is formulated into a rate allocation problem, where each node in the network will distributively solve the convex problem and all links or flows will converge to their optimal rate. The objective function and constraints of these problems are represented in a simplified model of contention, interference, and sending or receiving rates. The Partial Interference model is an optimal rate allocation model for use in wireless mesh networks that has been shown to be …
Modeling Wireless Networks For Rate Control, David C. Ripplinger
Modeling Wireless Networks For Rate Control, David C. Ripplinger
Theses and Dissertations
Congestion control algorithms for wireless networks are often designed based on a model of the wireless network and its corresponding network utility maximization (NUM) problem. The NUM problem is important to researchers and industry because the wireless medium is a scarce resource, and currently operating protocols such as 802.11 often result in extremely unfair allocation of data rates. The NUM approach offers a systematic framework to build rate control protocols that guarantee fair, optimal rates. However, classical models used with the NUM approach do not incorporate partial carrier sensing and interference, which can lead to significantly suboptimal performance when actually …
Packing Virtual Machines Onto Servers, David Luke Wilcox
Packing Virtual Machines Onto Servers, David Luke Wilcox
Theses and Dissertations
Data centers consume a significant amount of energy. This problem is aggravated by the fact that most servers and desktops are underutilized when powered on, and still consume a majority of the energy of a fully utilized computer even when idle This problem would be much worse were it not for the growing use of virtual machines. Virtual machines allow system administrators to more fully utilize hardware capabilities by putting more than one virtual system on the same physical server. Many times, virtual machines are placed onto physical servers inefficiently. To address this inefficiency, I developed a new family of …
Approximations With Improving Error Bounds For Makespan Minimization In Batch Manufacturing, Whitney Samuel Weyerman
Approximations With Improving Error Bounds For Makespan Minimization In Batch Manufacturing, Whitney Samuel Weyerman
Theses and Dissertations
Multipurpose batch manufacturing systems allow a suite of job types to be processed with a fixed set of machines. These types of systems are commonly found in chemical processing, as well as in computer systems and the service industry. In this thesis we consider the problem of sequencing jobs entering the manufacturing system in order to minimize makespan, or total time to complete processing of the jobs. We formulate this problem as a dynamic programming problem and illustrate the computational difficulty of solving this problem. We give a method for simulation of the system by representing each machine in the …
No Free Lunch, Bayesian Inference, And Utility: A Decision-Theoretic Approach To Optimization, Christopher Kenneth Monson
No Free Lunch, Bayesian Inference, And Utility: A Decision-Theoretic Approach To Optimization, Christopher Kenneth Monson
Theses and Dissertations
Existing approaches to continuous optimization are essentially mechanisms for deciding which locations should be sampled in order to obtain information about a target function's global optimum. These methods, while often effective in particular domains, generally base their decisions on heuristics developed in consideration of ill-defined desiderata rather than on explicitly defined goals or models of the available information that may be used to achieve them. The problem of numerical optimization is essentially one of deciding what information to gather, then using that information to infer the location of the global optimum. That being the case, it makes sense to model …