Master of Science / Department of Electrical and Computer Engineering / Caterina M. Scoglio / In network theory, a complex network represents a system whose evolving structure and dynamic behavior contribute to its robustness. The study of complex networks, though young, spans diverse domains including engineering, science, biology, sociology, psychology, and business, to name a few. Regardless of the field of interest, robustness defines a network’s survivability in the advent of classical component failures and at the onset of cryptic malicious attacks. With increasingly ambitious initiatives such as GENI and FIND that seek to design future internets, it becomes imperative to define the characteristics of robust topologies, and to build future networks optimized for robustness. This thesis investigates the characteristics of network topologies that maintain a high level of throughput in spite of multiple attacks. To this end, we select network topologies belonging to the main network models and some real world networks. We consider three types of attacks: removal of random nodes, high degree nodes, and high betweenness nodes. We use elasticity as our robustness measure and, through our analysis, illustrate that different topologies can have different degrees of robustness. In particular, elasticity can fall as low as 0.8% of the upper bound based on the attack employed. This result substantiates the need for optimized network topology design. Furthermore, we implement a trade off function that combines elasticity under the three attack strategies and considers the cost of the network. Our extensive simulations show that, for a given network density, regular and semi-regular topologies can have higher degrees of robustness than heterogeneous topologies, and that link redundancy is a sufficient but not necessary condition for robustness.

Master of Science / Department of Electrical and Computer Engineering / Anil Pahwa / Warren N. White / This thesis focuses on estimating the power loss from power panelboards by means of power loss models. The model is intended to be used by HVAC engineers to help estimate building heat loss. While McDonald & Hickok (1985) did not report power losses for power panelboards, Rubin (1979) did. These publications present the power losses of electrical devices at rated loads in tables. In this thesis, the models for electrical devices are created and used, instead of tables, to estimate power losses. The use of curve fit models presents a convenience in calculation of power losses. Breaker, fusible switch, and motor starter power losses presented by McDonald & Hickok (1985) and Rubin (1979) were updated using manufacturer published data, technical papers, industrial standards, and test samples. Test, manufacturer, and analytical model data are collected and power loss curve fit models are created for breakers, fusible switches, motor starters, and bus bars with enclosures. The panelboard power loss is calculated as the sum of partial power losses of the component electrical equipment, i.e. breakers, fusible switches, motor starters, and bus bars with enclosures used in power panelboards. A power loss model for main breaker and fusible switch power panelboards are created based on the sum of breaker, fusible switch, motor starter, and bus bars with enclosure power loss models. The main breaker and fusible switch power panelboard power loss models are used in a heat loss example. It is shown that power panelboard power losses can be significantly overestimated when calculated with one of the methods currently used (Rubin, 1979). This can result in erroneous sizing of HVAC equipment.

Master of Science / Department of Architectural Engineering and Construction Science / Sutton F. Stephens / The hazards of seismic activity on building structures require that engineers continually look for new and better methods of resisting seismic forces. Buckling restrained braced frames (BRBF) are a relatively new lateral force resisting system developed to resist highly unpredictable seismic forces in a very predictable way. Generally, structures with a more ductile lateral force resisting system perform better in resisting high seismic forces than systems with more rigid, brittle elements. The BRBF is a more ductile frame choice than special concentrically braced frames (SCBF). The ductility is gained through brace yielding in both compression and tension. The balanced hysteretic curve this produces provides consistent brace behavior under extreme seismic loads. However regular use of the BRB is largely limited to Japan where the brace type was first designed. The wide acceptance of buckling restrained braced frames requires the system to become easily designable, perform predictably, and common to engineers. This report explains the design process to help increase knowledge of the design and background. This report also details a comparison of a BRBF to a SCBF to give familiarity and promote confidence in the system. The design process of the BRBF is described in detail with design calculations of an example frame. The design process is from the AISC Seismic Provisions with the seismic loads calculated according to ASCE 7 equivalent lateral force procedure. The final members sizes of the BRBF and SCBF are compared based on forces and members selected. The results of the parametric study are discussed in detail.