Comparison of local pole assignment methods

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76770/1/AIAA-20171-818.pd

The V

This work is motivated by the need forr tools for the analysis of disturbance model uncertainty in feedback control systems. Such tools are developed in this paper for the case where the disturbance is modeled as the output of a first-order filter which is driven by white noise and whose bandwidth, ωd, and gain, K, are uncertain. An analytical expression for the steady-state output variance as a function of ωd is derived: This function is referred to as a V-transform, and is denoted by V(G)(ωd) , where G(s) is the closed-loop transfer function from disturbance to output. Properties of V-transforms are investigated and the notions of disturbance gain margin and disturbance bandwidth margin, both measures of robustness with respect to disturbance model uncertainty, are introduced. Using these new tools, it is shown that there is a fundamental robustness performance limitation if the plant has nonminimum-phase zeros, but no such limitation in the minimum-phase case

Perpetual Dynamic Soaring in Linear Wind Shear

A study was conducted to analyze dynamic soaring in linear wind shear and discuss the necessary and sufficient conditions to enable sustainable flight with dynamic soaring. The system under analysis was defined by a wind shear model with constant vertical velocity gradient and the aircraft equations of motion, which model the aircraft behavior when subject to a wind gradient. The study defined the inequalities that characterized the sufficient and necessary conditions for dynamic soaring. The conditions were applicable to a wide variety of unmanned aerial vehicles (UAVs), allowing the determination of the suitability of an aircraft for dynamic soaring under different environmental conditions. The equations of flight dynamics based on the flight-path and the lift were also derived in the study. The investigations derived the necessary and sufficient conditions for sustainable dynamic soaring as an explicit function of several aircraft and environment parameters. The characterization of the minimum vertical wind gradient dependence on environmental and aircraft parameters was obtained by running multiple trajectory optimizations, evaluating a range of values for several parameters

Toxoplasmosis prevalence in cats of Kingabwa and Limete résidentiel districts in Kinshasa

Durant sept mois, 150 échantillons de selles ont été collectés chez les chats des quartiers Kingabwa et Limete résidentiel à Kinshasa. Les analyses coprologiques par flottaison quantitative ont donné une prévalence brute de toxoplasmose de 14,7 %, à raison de 20 % à Kingabwa et de 8,6 % à Limete résidentiel pour ce qui est des quartiers (p? 0,05), de 13,3 % chez les mâles et de 16 % chez les femelles (p?0,05) concernant le sexe et de 16 % chez les chats âgés d’une année et plus et de 13,3 % chez ceux ayant moins d’une année (p?0,05) pour ce qui est de l’âge. Les chats joueraient un rôle important dans la forte prévalence de la toxoplasmose humaine observée à Kinshasa. Les médecins vétérinaires devront intégrer en plus du vermifugeage, l’administration de la pyriméthamine et de la sulfadiazine lors de la vaccination antirabique chez les chats afin de lutter contre la toxoplasmose féline. Mots-clés: Prévalence, Toxoplasmose, chats, Kingabwa, Limete résidentiel, Kinshasa.During seven months, 150 fecal samples were collected in cats of Kingabwa and residential Limete in Kinshasa. Coprological analysis by quantitative flotation gave a crude prevalence of 14.5 %, with 20 % prevalence at Kingabwa and 8.6 % for residential Limete in terms of neighborhoods (p?0.05), 13.3 % for males and 16 % for females (p?0,05) and 16 % of cats aged one year or more and 13.3 % in those with less than a year (p?0,05). Cats play an important role in the high prevalence of human toxoplasmosis observed in Kinshasa. Veterinarians should integrate, in addition to deworming, the administration of pyriméthamine and sulfadiazine at the time of anti-rabies vaccination of cats in order to fight against feline toxoplasmosis. Keywords: Prevalence, Toxoplasmosis, cats, Kingabwa, Limete residential, Kinshasa

Toxoplasmosis prevalence in cats of Kingabwa and Limete résidentiel districts in Kinshasa

During seven months, 150 fecal samples were collected in cats of Kingabwa and residential Limete in Kinshasa. Coprological analysis by quantitative flotation gave a crude prevalence of 14.5 %, with 20 % prevalence at Kingabwa and 8.6 % for residential Limete in terms of neighborhoods (p<0.05), 13.3 % for males and 16 % for females (p<0,05) and 16 % of cats aged one year or more and 13.3 % in those with less than a year (p<0,05). Cats play an important role in the high prevalence of human toxoplasmosis observed in Kinshasa. Veterinarians should integrate, in addition to deworming, the administration of pyriméthamine and sulfadiazine at the time of anti-rabies vaccination of cats in order to fight against feline toxoplasmosis

Optimal Path Planning for Unmanned Combat Aerial Vehicles to Defeat Radar Tracking

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76140/1/AIAA-14303-218.pd

A greedy policy for fleet-level radar resource management

A model for a phased-array radar in the context of a defensive Naval system has been developed using hierarchical finite state machines. This model is used to study resource management for a fleet of ships equipped with one radar unit each. This fleet is under attack from aerial enemy agents. A control algorithm formulated on this specific model is used to dynamically generate a greedy policy for radar operation. The defense system is evaluated in its capability to acquire and track those aerial threats, in two configurations -centralized and decentralized (independent). The performance is quantified on the basis of time taken to establish the threat trajectory, time to compute the policy and the number of threats the system fails to track. A comparison of performance in the two configurations is provided. ©2013 IEEE

A homotopy approach to the feedback stabilization of linear systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76174/1/AIAA-20236-533.pd

Norms, Networks, Power, and Control: Understanding Informal Payments and Brokerage in Cross-Border Trade in Sierra Leone

Recent research has cast light on the variety of informal payments and practices that govern the day-to-day interactions between traders and customs agents at border posts in low-income countries. Building on this literature, this paper draws on survey and qualitative evidence in an effort to explore which groups are most advantaged and disadvantaged by the largely informal processes and norms governing cross-border trade. We find that understanding variation in strategies and outcomes across traders can only be effectively understood with reference to the importance of norms, networks, power, and the logic of control.Department for International DevelopmentBill and Melinda Gates Foundatio

Solar-Powered Aircraft: Energy-Optimal Path Planning and Perpetual Endurance

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76439/1/AIAA-40139-801.pd