Optimistic Robust Optimization With Applications To Machine Learning

Robust Optimization has traditionally taken a pessimistic, or worst-case viewpoint of uncertainty which is motivated by a desire to find sets of optimal policies that maintain feasibility under a variety of operating conditions. In this paper, we explore an optimistic, or best-case view of uncertainty and show that it can be a fruitful approach. We show that these techniques can be used to address a wide variety of problems. First, we apply our methods in the context of robust linear programming, providing a method for reducing conservatism in intuitive ways that encode economically realistic modeling assumptions. Second, we look at problems in machine learning and find that this approach is strongly connected to the existing literature. Specifically, we provide a new interpretation for popular sparsity inducing non-convex regularization schemes. Additionally, we show that successful approaches for dealing with outliers and noise can be interpreted as optimistic robust optimization problems. Although many of the problems resulting from our approach are non-convex, we find that DCA or DCA-like optimization approaches can be intuitive and efficient

The development, optimisation and testing of an unmanned parafoil launch system

Includes summary.Includes bibliographical references (leaves 70-73).Parafoils have been used in various aerospace, military and sport applications to return both personnel and payloads safely to the ground. Deflection of the trailing edge flaps by means of control lines allows for turn rates of up to 60° per second, which provides superior controllability when compared to conventional round parachutes. This steering ability has led to the development of autonomous control systems that are able to navigate a payload to land in close proximity to a designated landing site. In order to develop an autonomous navigation system a suitable dynamic model of the parafoil with suspended payload is required to determine the parameters and characteristics of the system in free flight. Flexible ram-air inflated parafoils display high sensitivity to atmospheric disturbances which complicates the comparison of measured flight-dynamic data to theoretical models in an open air free flight test. In order to improve the quality of results in studying the flight dynamics of an unmanned parafoil system in free flight, controlled conditions and a repeatable flight path are required to perform data analysis for various trim configurations. This leads to the requirement of a launching system that ensures consistent inflation of the canopy and repeatable launch velocities for various canopy and payload configurations

Developing a curriculum of open educational resources for Linked Data

The EUCLID project is developing an educational curriculum about Linked Data, supported by multimodal Open Educational Resources (OERs) tailored to the real needs of data practitioners. The EUCLID OERs facilitate professional training for data practitioners, who aim to use Linked Data in their daily work. The EUCLID OERs are implemented as a combination of living learning materials and activities (eBook, online courses, webinars, face-to-face training), produced via a rigorous process and validated by the user community through continuous feedback

Data quality predicts care quality: findings from a national clinical audit

Background: Missing clinical outcome data are a common occurrence in longitudinal studies. Data quality in clinical audit is a particular cause for concern. The relationship between departmental levels of missing clinical outcome data and care quality is not known. We hypothesise that completeness of key outcome data in a national audit predicts departmental performance. Methods: The National Clinical Audit for Rheumatoid and Early Inflammatory Arthritis (NCAREIA) collected data on care of patients with suspected rheumatoid arthritis (RA) from early 2014 to late 2015. This observational cohort study collected data on patient demographics, departmental variables, service quality measures including time to treatment, and the key RA clinical outcome measure, disease activity at baseline, and 3 months follow-up. A mixed effects model was conducted to identify departments with high/low proportions of missing baseline disease activity data with the results plotted on a caterpillar graph. A mixed effects model was conducted to assess if missing baseline disease activity predicted prompt treatment. Results: Six thousand two hundred five patients with complete treatment time data and a diagnosis of RA were recruited from 136 departments. 34.3% had missing disease activity at baseline. Mixed effects modelling identified 13 departments with high levels of missing disease activity, with a cluster observed in the Northwest of England. Missing baseline disease activity was associated with not commencing treatment promptly in an adjusted mix effects model, odds ratio 0.50 (95% CI 0.41 to 0.61, p < 0.0001). Conclusions: We have shown that poor engagement in a national audit program correlates with the quality of care provided. Our findings support the use of data completeness as an additional service quality indicator

EUCLID: EdUcational curriculum for the usage of LInked data

Linked Data has established itself as an emerging standard for the publication of structured data over the Web, enjoying amazing growth in terms of the number of organizations committing to use its best practices and technologies for ex- posing and interlinking data sets for seamless exchange, integration, and reuse. More and more ICT ventures offer innovative data management services on top of Linked (Open) Data, creating a demand for data practitioners with a back- ground in semantic technologies. Ensuring the availability of such expertise will prove crucial if European businesses are to reap the full benefits of the advanced data management technology, and the know-how accumulated over the past years by researchers, technology enthusiasts and early adopters in various European countries. EUCLID had a major contribution to this goal by providing a com- prehensive educational curriculum, supported by multi-modal training materials and state-of-the-art eLearning distribution channels, tailored to the real needs of data practitioners. Building upon experience reports from over twenty Linked Data projects with over forty companies and public offices in more than ten countries, complemented by feedback from hundreds of training events, and an in-depth analysis of the community discourse through mailing lists, discussion forums, Twitter, and the blogosphere, the curriculum focuses on techniques and software to integrate, query, and visualize Linked Data, as core areas in which practitioners state to require most assistance. It is realized as a combination of multi-modal learning resources, including an iBook published on iTunes U, and evaluated through webinars, f2f training, and continuous community feedback. By providing these key knowledge-transfer components, EUCLID will not only promote the industrial uptake of Linked Data best practices and technologies, but, most importantly, will contribute to their further development and consol- idation, and support the sustainability of the community, all essential aspects given the rapid pace at which the field has recently advanced

The natural space environment: Effects on spacecraft

The effects of the natural space environments on spacecraft design, development, and operation are the topic of a series of NASA Reference Publications currently being developed by the Electromagnetics and Environments Branch, Systems Analysis and Integration Laboratory, Marshall Space Flight Center. This primer provides an overview of the natural space environments and their effect on spacecraft design, development, and operations, and also highlights some of the new developments in science and technology for each space environment. It is hoped that a better understanding of the space environment and its effect on spacecraft will enable program management to more effectively minimize program risks and costs, optimize design quality, and successfully achieve mission objectives

Residues from cyclododecane consolidation following desalination

This paper is published in the book ‘Subliming Surfaces: Volatile Binding Media in Heritage Conservation’, ed. Christina Rozeik (University of Cambridge Museums, 2018), pp. 101-107.1500 Central and South American archaeological ceramics in the Field Museum of Natural History, Chicago, required desalination treatment. Cyclododecane (CDD) was investigated as a temporary consolidant for extremely friable ceramics during desalination, leading to an investigation of post-sublimation residue. Watch glasses, new unglazed terracotta saucers, and thick potsherds from the archaeological collection were treated and desalinated. No residues were detected after sublimation on watch glasses, the saucers, and archaeological potsherds that did not undergo desalination. Residues were found on all archaeological potsherds that were desalinated. Microscopical study and infrared spectroscopy (ATR-FTIR) indicated the residue to be primarily of biological origin. Its presence could result from the growth within the CDD of bacteria, mould and yeast present in the archaeological ceramic. There was no evidence of CDD remaining in the residue. Residues on desalinated potsherds consolidated with molten CDD were thin, lightly cohesive sheets. The residue could be lifted off with electrostatically charged nylon brush or polyester film. Residues formed in the CDD applied as a solution were less cohesive and could only be removed by brushing. In most cases, some ceramic particles were lost. It was concluded that temporary consolidation with CDD was not useful in desalination treatments