Engineering Commons^™

Exact And Approximate Relaxation Techniques For Computational Guidance, Sheril Avikkal Kunhippurayil

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The focus of this dissertation is in the development and application of relaxation techniques that enable efficient and real-time solution of complex computational guidance problems. Relaxations transform a non-convex constraint into a convex constraint and provides proof that the optimal solutions to the relaxed problem are optimal for the original problem. Unique contributions of this work include: 1) a relaxation technique for solving fixed final time problems between fixed points, 2) a performance analysis on the application of computational guidance for the Mars Ascent Vehicle, and 3) establishment of sufficient conditions for non-singularity of optimal control for problems on a …

Graph Automorphic Approaches To The Robustness Of Complex Networks, Hossein Parastvand, Airlie Chapman, Octavian Bass, Stefan Lachowicz

Research outputs 2014 to 2021

© 2020 Elsevier Ltd Leveraging on graph automorphic properties of complex networks (CNs), this study investigates three robustness aspects of CNs including the robustness of controllability, disturbance decoupling, and fault tolerance against failure in a network element. All these aspects are investigated using a quantified notion of graph symmetry, namely the automorphism group, which has been found implications for the network controllability during the last few years. The typical size of automorphism group is very big. The study raises a computational issue related to determining the whole set of automorphism group and proposes an alternative approach which can attain the …

Power Network And Smart Grids Analysis From A Graph Theoretic Perspective, Hossein Parast Vand

Theses: Doctorates and Masters

The growing size and complexity of power systems has given raise to the use of complex network theory in their modelling, analysis, and synthesis. Though most of the previous studies in this area have focused on distributed control through well established protocols like synchronization and consensus, recently, a few fundamental concepts from graph theory have also been applied, for example in symmetry-based cluster synchronization. Among the existing notions of graph theory, graph symmetry is the focus of this proposal. However, there are other development around some concepts from complex network theory such as graph clustering in the study.

In spite …

Cyber-Security Constrained Placement Of Facts Devices In Power Networks From A Novel Topological Perspective, Hossein Parastvand, Octavian Bass, Mohammad A. S. Masoum, Airlie Chapman, Stefan Lachowicz

Research outputs 2014 to 2021

Optimal placement of flexible AC transmission systems (FACTS) devices and the cyber-security of associated data exchange are crucial for the controllability of wide area power networks. The placement of FACTS devices is studied in this paper from a novel graph theoretic perspective, which unlike the existing approaches, purely relies on topological characteristics of the underlying physical graphs of power networks. To this end, the maximum matching principle (MMP) is used to find the set of required FACTS devices for the grid controllability. In addition, the cyber-security of the most critical data related to the FACTS controllers is guaranteed by introducing …

Methodologies To Exploit Atpg Tools For De-Camouflaging, Deepak Reddy Vontela

USF Tampa Graduate Theses and Dissertations

Semiconductor supply chain is increasingly getting exposed to Reverse Engineering (RE) of Intellectual Property (IP). Camouflaging of gates in integrated circuits are typically employed to hide the gate functionality to prevent reverse engineering. The functionalities of these gates cannot be found by De-layering as they don’t leave any layout clues. Adversaries perform reverse engineering by replacing the camouflaged gate with the known gate and by developing custom software to determine test patterns. These test patterns are used to analyze the outputs and to conclude the functionality of the camouflaged gate.

In this thesis, we show that reverse engineering of camouflaged …

Controllability And Observability Of A Large Scale Thermodynamical System Via Connectability Approach, Virdiansyah Permana

Electronic Theses and Dissertations

This study presents a new approach to determine the controllability and observability of a large scale nonlinear dynamic thermal system using graph-theory. The novelty of this method is in adapting graph theory for nonlinear class and establishing a graphic condition that describes the necessary and sufficient terms for a nonlinear class system to be controllable and observable, which equivalents to the analytical method of Lie algebra rank condition. The graph theory of a directed graph (digraph) is utilized to model the system, and the rule of its adaptation in nonlinear class is defined. Subsequently, necessary and sufficient terms to achieve …

Energy-Efficient Complex Distillation Sequences: Control Properties, Salvador Robles-Zapiain, Juan Gabriel Segovia-Hernández, Adrian Bonilla-Petriciolet, Rafael Maya-Yescas

Adrian Bonilla-Petriciolet

Four thermally coupled distillation systems were designed for the separation of five-component mixtures (the light-ends separation section of a crude distillation plant); their steady-state design was obtained by starting from a conventional distillation sequence and then optimizing for minimum energy consumption. The thermally coupled distillation systems were compared to sequence based on conventional columns design. Comparison was based on controllability properties under open and closed loop operation, following the dynamic behaviour after common industrial operating disturbances. Simulation results were analyzed by the singular value decomposition technique and with the performance examination of elimination of feed disturbances using PI controllers. It …