Europe
Boosting Search Guidance in Problems with Semantic Attachments
Bernardini, Sara (Royal Holloway, University of London) | Fox, Maria (King's College London) | Long, Derek (King's College London) | Piacentini, Chiara (University of Toronto)
Most applications of planning to real problems involve complex and often non-linear equations, including matrix operations. PDDL is ill-suited to express such calculations since it only allows basic operations between numeric fluents. To remedy this restriction, a generic PDDL planner can be connected to a specialised advisor, which equips the planner with the ability to carry out sophisticated mathematical operations. Unlike related techniques based on semantic attachment, our planner is able to exploit an approximation of the numeric information calculated by the advisor to compute informative heuristic estimators. Guided by both causal and numeric information, our planning framework outperforms traditional approaches, especially against problems with numeric goals. We provide evidence of the power of our solution by successfully solving four completely different problems.
This Is a Solution! (... But Is It Though?) - Verifying Solutions of Hierarchical Planning Problems
Behnke, Gregor (Ulm University) | Hรถller, Daniel (Ulm University) | Biundo, Susanne (Ulm University)
Plan-Verification is the task of determining whether a plan is a solution to a given planning problem. Any plan verifier has, apart from showing that verifying plans is possible in practice, a wide range of possible applications. These include mixed-initiative planning, where a user is integrated into the planning process, and local search, e.g., for post-optimising plans or for plan repair. In addition to its practical interest, plan verification is also a problem worth investigating for theoretical reasons. Recent work showed plan verification for hierarchical planning problems to be NP-complete, as opposed to classical planning where it is in P. As such, plan verification for hierarchical planning problem was โ until now โ not possible. We describe the first plan verifier for hierarchical planning. It uses a translation of the problem into a SAT formula. Further we conduct an empirical evaluation, showing that the correct output is produced within acceptable time.
A State-Space Acyclicity Property for Exponentially Tighter Plan Length Bounds
Abdulaziz, Mohammad (The Australian National University and Data61) | Gretton, Charles (HIVERY) | Norrish, Michael (The Australian National University and Data61)
We investigate compositional bounding of transition system diameters, with application in bounding the lengths of plans. We establish usefully-tight bounds by exploiting acyclicity in state-spaces. We provide mechanised proofs in HOL4 of the validity of our approach. Evaluating our bounds in a range of benchmarks, we demonstrate exponentially tighter upper bounds compared to existing methods. Treating both solvable and unsolvable benchmark problems, we also demonstrate the utility of our bounds in boosting planner performance. We enhance an existing planning procedure to use our bounds, and demonstrate significant coverage improvements, both compared to the base planner, and also in comparisons with state-of-the-art systems.
$\nu$-net: Deep Learning for Generalized Biventricular Cardiac Mass and Function Parameters
Winther, Hinrich B, Hundt, Christian, Schmidt, Bertil, Czerner, Christoph, Bauersachs, Johann, Wacker, Frank, Vogel-Claussen, Jens
Background: Cardiac MRI derived biventricular mass and function parameters, such as end-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF), stroke volume (SV), and ventricular mass (VM) are clinically well established. Image segmentation can be challenging and time-consuming, due to the complex anatomy of the human heart. Objectives: This study introduces $\nu$-net (/nju:n$\varepsilon$t/) -- a deep learning approach allowing for fully-automated high quality segmentation of right (RV) and left ventricular (LV) endocardium and epicardium for extraction of cardiac function parameters. Methods: A set consisting of 253 manually segmented cases has been used to train a deep neural network. Subsequently, the network has been evaluated on 4 different multicenter data sets with a total of over 1000 cases. Results: For LV EF the intraclass correlation coefficient (ICC) is 98, 95, and 80 % (95 %), and for RV EF 96, and 87 % (80 %) on the respective data sets (human expert ICCs reported in parenthesis). The LV VM ICC is 95, and 94 % (84 %), and the RV VM ICC is 83, and 83 % (54 %). This study proposes a simple adjustment procedure, allowing for the adaptation to distinct segmentation philosophies. $\nu$-net exhibits state of-the-art performance in terms of dice coefficient. Conclusions: Biventricular mass and function parameters can be determined reliably in high quality by applying a deep neural network for cardiac MRI segmentation, especially in the anatomically complex right ventricle. Adaption to individual segmentation styles by applying a simple adjustment procedure is viable, allowing for the processing of novel data without time-consuming additional training.
Predictive modelling of training loads and injury in Australian football
Carey, David L., Ong, Kok-Leong, Whiteley, Rod, Crossley, Kay M., Crow, Justin, Morris, Meg E.
To investigate whether training load monitoring data could be used to predict injuries in elite Australian football players, data were collected from elite athletes over 3 seasons at an Australian football club. Loads were quantified using GPS devices, accelerometers and player perceived exertion ratings. Absolute and relative training load metrics were calculated for each player each day (rolling average, exponentially weighted moving average, acute:chronic workload ratio, monotony and strain). Injury prediction models (regularised logistic regression, generalised estimating equations, random forests and support vector machines) were built for non-contact, non-contact time-loss and hamstring specific injuries using the first two seasons of data. Injury predictions were generated for the third season and evaluated using the area under the receiver operator characteristic (AUC). Predictive performance was only marginally better than chance for models of non-contact and non-contact time-loss injuries (AUC$<$0.65). The best performing model was a multivariate logistic regression for hamstring injuries (best AUC=0.76). Learning curves suggested logistic regression was underfitting the load-injury relationship and that using a more complex model or increasing the amount of model building data may lead to future improvements. Injury prediction models built using training load data from a single club showed poor ability to predict injuries when tested on previously unseen data, suggesting they are limited as a daily decision tool for practitioners. Focusing the modelling approach on specific injury types and increasing the amount of training data may lead to the development of improved predictive models for injury prevention.
Improving Variational Auto-Encoders using convex combination linear Inverse Autoregressive Flow
Tomczak, Jakub M., Welling, Max
In this paper, we propose a new volume-preserving flow and show that it performs similarly to the linear general normalizing flow. The idea is to enrich a linear Inverse Autoregressive Flow by introducing multiple lower-triangular matrices with ones on the diagonal and combining them using a convex combination. In the experimental studies on MNIST and Histopathology data we show that the proposed approach outperforms other volume-preserving flows and is competitive with current state-of-the-art linear normalizing flow.
The Inflation Technique for Causal Inference with Latent Variables
Wolfe, Elie, Spekkens, Robert W., Fritz, Tobias
The problem of causal inference is to determine if a given probability distribution on observed variables is compatible with some causal structure. The difficult case is when the causal structure includes latent variables. We here introduce the $\textit{inflation technique}$ for tackling this problem. An inflation of a causal structure is a new causal structure that can contain multiple copies of each of the original variables, but where the ancestry of each copy mirrors that of the original. To every distribution of the observed variables that is compatible with the original causal structure, we assign a family of marginal distributions on certain subsets of the copies that are compatible with the inflated causal structure. It follows that compatibility constraints for the inflation can be translated into compatibility constraints for the original causal structure. Even if the constraints at the level of inflation are weak, such as observable statistical independences implied by disjoint causal ancestry, the translated constraints can be strong. We apply this method to derive new inequalities whose violation by a distribution witnesses that distribution's incompatibility with the causal structure (of which Bell inequalities and Pearl's instrumental inequality are prominent examples). We describe an algorithm for deriving all such inequalities for the original causal structure that follow from ancestral independences in the inflation. For three observed binary variables with pairwise common causes, it yields inequalities that are stronger in at least some aspects than those obtainable by existing methods. We also describe an algorithm that derives a weaker set of inequalities but is more efficient. Finally, we discuss which inflations are such that the inequalities one obtains from them remain valid even for quantum (and post-quantum) generalizations of the notion of a causal model.
Drones Can Aid Those Suffering A Cardiac Arrest Before Ambulance Arrives, Researchers Say
If someone has a cardiac arrest, a drone could help before an ambulance arrives. Swedish researchers have been experimenting with drones treating an individual whose heart stops, New Scientist reported. Out-of-hospital cardiac arrest happens to about 55 of 100,000 people in the U.S. annually, with only an 8 percent to 10 percent survival rate. Getting an ambulance in time could save a person's life, but what if first responders take too long? Researchers from the Karolinska Institute looked at an alternative: drones equipped with defibrillators that could aid a person in cardiac arrest if applied quickly.
How AI is improving customer experience and loyalty in retail
The use of artificial intelligence (AI) is expanding across all industries. Forrester predicts that this year alone there will be a 300% increase in investment in artificial intelligence. Companies worldwide are starting to use the power of AI to enhance their capabilities and deliver improved experiences to customers. Retail is an industry where AI use is relatively new, but it is gaining speed due to customer interest. JWT Intelligence research shows that 62% of millennials in the UK say they would appreciate a brand or retailer using AI technology to show more interesting products.
From Zero to Hero in Two Years: Artificial Intelligence to be One of Biggest Digital Disruptors in Supply Chain
Artificial intelligence (AI) has been a part of popular culture for decades, from wreaking havoc in The Terminator movie in the '80s to saving the world in Iron Man 3. While Hollywood loves to highlight the more extreme consequences of AI, the real-life business implications are far more tangible, with the supply chain industry standing front and center as one of the big winners from this game-changing technology. The role of AI within supply chain grew so quickly that in our Future of Supply Chain survey in 2014, we didn't even ask SCM World's community of senior supply chain professionals about its importance. If we jump forward two years to 2016, however, the numbers indicate that people are very much aware of the technology's ability to deliver tangible value within the supply chain industry. In fact, 47 percent of the almost 1,500 respondents to our most recent survey said that AI was both disruptive and important in respect to supply chain strategies.