2007 Convocation

Prelude Music: Joanna Messer, 1997 IMSA Graduate Pledge of Allegiance & Welcome: Jonathan Koch, Student Council President; Dr. Max McGee, President; Dr. Eric McLaren, Principal Featured Piece: Joanna Messer, 1997 IMSA Graduate Keynote Speaker: Jessica Droste Yagan, Sam D. Yagan; 1995 IMSA Graduate

Effects of temporal correlations in social multiplex networks

Multi-layered networks represent a major advance in the description of natural complex systems, and their study has shed light on new physical phenomena. Despite its importance, however, the role of the temporal dimension in their structure and function has not been investigated in much detail so far. Here we study the temporal correlations between layers exhibited by real social multiplex networks. At a basic level, the presence of such correlations implies a certain degree of predictability in the contact pattern, as we quantify by an extension of the entropy and mutual information analyses proposed for the single-layer case. At a different level, we demonstrate that temporal correlations are a signature of a ‘multitasking’ behavior of network agents, characterized by a higher level of switching between different social activities than expected in a uncorrelated pattern. Moreover, temporal correlations significantly affect the dynamics of coupled epidemic processes unfolding on the network. Our work opens the way for the systematic study of temporal multiplex networks and we anticipate it will be of interest to researchers in a broad array of fields

Owner-Level Taxes and Business Activity

In some classes of models, taxes at the owner level are "neutral" and have no effect on firm activity. However, this tax neutrality is sensitive to assumptions and no longer holds in more complex models. We review recent research that incorporates greater complexity in studying the link between taxes and business activity - particularly entrepreneurship. Dividend taxes on owners of large firms affect firm activity in models that include agency conflicts between owners and managers. Similarly, after incorporating entrepreneurs' occupational choice into the model, taxes are no longer neutral. By forsaking lucrative alternative careers, skilled entrepreneurs tend to have high opportunity costs, which make the choice of attempting to start a business of first order importance. Moreover, in models where it is assumed that capital flows across borders without cost, taxes on domestic business owners do not alter business activity because foreign capital seamlessly compensates for tax-induced declines in investments. This theoretical notion is contradicted by the strong "home bias" observed in business ownership, in particular for small firms and startups without easy access to international capital markets. Recent empirical work has emphasized that taxes have heterogeneous effects on mature firms, entrepreneurial startups, and owner-managed small firms. Lowering dividend taxes on firms with dispersed ownership has been shown to shift capital from mature firms into rapidly growing firms. Moreover, capital gains taxation tends to reduce the number of innovative startups and diminish venture capital activity, while high owner-level taxes encourage small business activity and non-entrepreneurial self-employment because such firms have more opportunities to avoid or evade taxes. To obtain efficient incentives in entrepreneurial startups, contractual terms are required that ex ante guarantee that all providers of critical inputs, especially equity constrained entrepreneurs, are entitled to a share of the resulting capital value firm. Unless properly designed, owner-level taxes prevent such ex ante contracting and thus lower the likelihood of eventual success

SEM-EDS characterization of natural products on corrosion inhibition of Al-Mg-Si alloy

The corrosion resistance of aluminum and its alloys is the subject of tremendous technological importance due to their increased industrial applications. The corrosion protections and the mechanism of corrosion inhibitions of natural products for an Al-Mg-Si alloy in seawater were investigated at room temperature. The surface morphology was studied by means of macro scale electrochemical techniques and localized microscopic methods, i.e., Scanning electron microscope (SEM) with associated elemental analysis by energy dispersive spectrometer (EDS). SEM examinations provided morphological characterization of the surface of Al-Mg-Si alloy sample before and after immersion in seawater; meanwhile surface analytical techniques by the EDS allowed us to investigate detail the chemical composition of aluminum oxide layers. The experiments were performed with Al-Mg-Si alloy, immersed in a 5 L beaker containing seawater with and without the natural products for 60 days at room temperature. The SEM results indicate that the natural products (natural honey, vanillin, and tapioca starch) absolutely inhibited the corrosion products on the specimen surfaces. They also protected the passive film from dissolution in seawater. The EDS spectrums were determined that carbonaceous, carbonyl, methoxy and hydroxyl groups as functional groups of natural products in inhibition mechanism

Coordinated reinforcement learning for decentralized optimal control

10.1109/ADPRL.2007.368202Proceedings of the 2007 IEEE Symposium on Approximate Dynamic Programming and Reinforcement Learning, ADPRL 2007296-30

Distributed model-free stochastic optimization in wireless sensor networks

10.1007/11776178_6Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)4026 LNCS85-10