Administrative Management Capacity in Out-of-School Time Organizations: An Exploratory Study

Based on interviews with sixteen high-quality out-of-school time (OST) program providers, identifies the managerial and administrative needs of OST nonprofits such as financial and human resources management and information technology. Suggests solutions

Distributed Model Predictive Consensus via the Alternating Direction Method of Multipliers

We propose a distributed optimization method for solving a distributed model predictive consensus problem. The goal is to design a distributed controller for a network of dynamical systems to optimize a coupled objective function while respecting state and input constraints. The distributed optimization method is an augmented Lagrangian method called the Alternating Direction Method of Multipliers (ADMM), which was introduced in the 1970s but has seen a recent resurgence in the context of dramatic increases in computing power and the development of widely available distributed computing platforms. The method is applied to position and velocity consensus in a network of double integrators. We find that a few tens of ADMM iterations yield closed-loop performance near what is achieved by solving the optimization problem centrally. Furthermore, the use of recent code generation techniques for solving local subproblems yields fast overall computation times.Comment: 7 pages, 5 figures, 50th Allerton Conference on Communication, Control, and Computing, Monticello, IL, USA, 201

Approximate Dynamic Programming via Sum of Squares Programming

We describe an approximate dynamic programming method for stochastic control problems on infinite state and input spaces. The optimal value function is approximated by a linear combination of basis functions with coefficients as decision variables. By relaxing the Bellman equation to an inequality, one obtains a linear program in the basis coefficients with an infinite set of constraints. We show that a recently introduced method, which obtains convex quadratic value function approximations, can be extended to higher order polynomial approximations via sum of squares programming techniques. An approximate value function can then be computed offline by solving a semidefinite program, without having to sample the infinite constraint. The policy is evaluated online by solving a polynomial optimization problem, which also turns out to be convex in some cases. We experimentally validate the method on an autonomous helicopter testbed using a 10-dimensional helicopter model.Comment: 7 pages, 5 figures. Submitted to the 2013 European Control Conference, Zurich, Switzerlan

On the connections between PCTL and Dynamic Programming

Probabilistic Computation Tree Logic (PCTL) is a well-known modal logic which has become a standard for expressing temporal properties of finite-state Markov chains in the context of automated model checking. In this paper, we give a definition of PCTL for noncountable-space Markov chains, and we show that there is a substantial affinity between certain of its operators and problems of Dynamic Programming. After proving some uniqueness properties of the solutions to the latter, we conclude the paper with two examples to show that some recovery strategies in practical applications, which are naturally stated as reach-avoid problems, can be actually viewed as particular cases of PCTL formulas.Comment: Submitte

Submodularity of Energy Related Controllability Metrics

The quantification of controllability and observability has recently received new interest in the context of large, complex networks of dynamical systems. A fundamental but computationally difficult problem is the placement or selection of actuators and sensors that optimize real-valued controllability and observability metrics of the network. We show that several classes of energy related metrics associated with the controllability Gramian in linear dynamical systems have a strong structural property, called submodularity. This property allows for an approximation guarantee by using a simple greedy heuristic for their maximization. The results are illustrated for randomly generated systems and for placement of power electronic actuators in a model of the European power grid.Comment: 7 pages, 2 figures; submitted to the 2014 IEEE Conference on Decision and Contro

The future of Indigenous policy on remote communities

Adelaide, S

On Submodularity and Controllability in Complex Dynamical Networks

Controllability and observability have long been recognized as fundamental structural properties of dynamical systems, but have recently seen renewed interest in the context of large, complex networks of dynamical systems. A basic problem is sensor and actuator placement: choose a subset from a finite set of possible placements to optimize some real-valued controllability and observability metrics of the network. Surprisingly little is known about the structure of such combinatorial optimization problems. In this paper, we show that several important classes of metrics based on the controllability and observability Gramians have a strong structural property that allows for either efficient global optimization or an approximation guarantee by using a simple greedy heuristic for their maximization. In particular, the mapping from possible placements to several scalar functions of the associated Gramian is either a modular or submodular set function. The results are illustrated on randomly generated systems and on a problem of power electronic actuator placement in a model of the European power grid.Comment: Original arXiv version of IEEE Transactions on Control of Network Systems paper (Volume 3, Issue 1), with a addendum (located in the ancillary documents) that explains an error in a proof of the original paper and provides a counterexample to the corresponding resul

"The Coldest Sport in the World": Iceboating in Toronto Harbour, 1824-1941

In 1987, the Marine Museum of Upper Canada acquired an iceboat last used in Toronto Har-bour in the late 1960s, which was said to have been constructed around the turn of the cen-tury. Subsequent research into the sport of ice-boating inToronto, from the 1820s to the end of World War II, has revealed it to be of con-siderable interest from both social and tech-nological points of view. The boats were used for winter transportation to and from the Toronto Island, and were also raced with fierce competitiveness around triangular courses on the frozen harbour. This article examines the growth and devel-opment of iceboating in Toronto through the period of its greatest popularity to its eventual decline, with an emphasis on the development of the form and rig of the iceboats. By the mid nineteenth century, a distinctive Toronto type of iceboat had emerged, and it predominated in the city up until the 1930s, when finally supplanted by more modem models. The preva-lence of these lateen-rigged stem-steering boats in Toronto long after the development and dominance of marconi-rigged bow-steerers elsewhere is an interesting example of insularity in small craft development. Résumé En 1987, le Marine Museum of Upper Canada a fait l'acquisition d'un ice-boat (planche à voile sur patins) utilisé pour la dernière fois dans le port de Toronto à la fin des années 1960, dont on disait qu'il avait été construit au tournant du siècle. Des recherches subséquentes sur la pratique du sport de Tice-boat à Toronto des années 1820 jusqu'à la fin de la Seconde Guerre mondiale ont révélé que ce genre d'embarcation présentait un intérêt considérable, sur le plan tant social que technique. Les ice-boats servaient l'hiver au transport entre l'île de Toronto et la terre ferme et, en outre, ils étaient pilotés avec un esprit de concurrence féroce sur des pistes de course triangulaires aménagées sur l'aire glacée du port. L'article passe en revue les étapes de la croissance et du développement de l'ice-boat à Toronto, de son âge d'or à son déclin, en s'attardant plus particulièrement au développement de la forme et du gréement de ce genre d'embarcation. Le milieu du XIXe siècle a vu l'apparition d'un type torontois d'ice-boat, qui a prédominé jusqu'aux années 1930 alors qu'il a été supplanté par des modèles plus modernes. L'engouement continu des Torontois pour ces ice-boats gréés de voiles latines avec roue de barre en poupe, longtemps après le développement et la prédominance ailleurs d'ice-boats à voile marconi avec roue de barre en proue, constitue un intéressant exemple d'insularité dans le domaine du développement d'embarcations de petites dimensions