Best practice, best teaching

Keynote address discussing examples from my own, colleagues, and attendees practice. Conference participants worked in groups to share and build upon their existing teaching and learning strategies

Building an evaluative culture for effective evaluation and results management

A weak evaluative culture undermines many attempts at building an effective evaluation and results management regime. This brief outlines practical actions that an organization can take to build and support an evaluative culture, where information on performance is deliberately sought in order to learn how to better manage and deliver programmes and services. Such an organization values empirical evidence on the results it is seeking to achieve.evaluation, culture, Agricultural and Food Policy, Research and Development/Tech Change/Emerging Technologies,

The Great Naval Battle of North Point: Myth or Reality?

Hollywood itself could hardly have scripted a better battle. According to eyewitnesses, a German U-boat lurking off the shores of North Point, Prince Edward Island, laid a trap for an unsuspecting convoy transitting the Northumberland Strait. On 7 May 1943, the trap was sprung, Canadian naval escorts and aircraft did their best to defend the beleaguered convoy from a brazen and unorthodox attack that was unlike any other. There could only be one conclusion: the German commander was half-mad. Just like the fictional Captain Ahab, he was willing to take unwarranted risks with his boat and men to destroy his white whale that came in the form of a troop ship at the centre of the convoy. His obsession led to a stunning three hour engagement that was brought to a dramatic end as the Canadians scored a direct hit forcing the U-boat’s bow to rise sharply out of the water before sinking. The problem is that there is no evidence that this battle ever took place

Are pre-MS stars older than we thought?

We present a consistent age ordering for young clusters and groups determined using the contraction of stars through their pre-main-sequence phase. We compare these with ages derived from the evolution of the upper main-sequence stars, and find the upper MS ages are older by a factor 1.5 to 2. We show that increasing the binary fraction and number of equal-mass binaries amongst the O-stars compared to the rest of the MS cannot remove this discrepancy.Comment: 1 page. Special Session 7, IAU XXVII General Assembl

Safety Control Synthesis with Input Limits: a Hybrid Approach

We introduce a hybrid (discrete--continuous) safety controller which enforces strict state and input constraints on a system---but only acts when necessary, preserving transparent operation of the original system within some safe region of the state space. We define this space using a Min-Quadratic Barrier function, which we construct along the equilibrium manifold using the Lyapunov functions which result from linear matrix inequality controller synthesis for locally valid uncertain linearizations. We also introduce the concept of a barrier pair, which makes it easy to extend the approach to include trajectory-based augmentations to the safe region, in the style of LQR-Trees. We demonstrate our controller and barrier pair synthesis method in simulation-based examples.Comment: 6 pages, 7 figures. Accepted for publication at the 2018 American Controls Conference. Copyright IEEE 201

Nested Distributed Model Predictive Control

We propose a distributed model predictive control approach for linear time-invariant systems coupled via dynamics. The proposed approach uses the tube MPC concept for robustness to handle the disturbances induced by mutual interactions between subsystems; however, the main novelty here is to replace the conventional linear disturbance rejection controller with a second MPC controller, as is done in tube-based nonlinear MPC. In the distributed setting, this has the advantages that the disturbance rejection controller is able to consider the plans of neighbours, and the reliance on explicit robust invariant sets is removed