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Patient Similarity Analysis with Longitudinal Health Data
Allam, Ahmed, Dittberner, Matthias, Sintsova, Anna, Brodbeck, Dominique, Krauthammer, Michael
Healthcare professionals have long envisioned using the enormous processing powers of computers to discover new facts and medical knowledge locked inside electronic health records. These vast medical archives contain time-resolved information about medical visits, tests and procedures, as well as outcomes, which together form individual patient journeys. By assessing the similarities among these journeys, it is possible to uncover clusters of common disease trajectories with shared health outcomes. The assignment of patient journeys to specific clusters may in turn serve as the basis for personalized outcome prediction and treatment selection. This procedure is a non-trivial computational problem, as it requires the comparison of patient data with multi-dimensional and multi-modal features that are captured at different times and resolutions. In this review, we provide a comprehensive overview of the tools and methods that are used in patient similarity analysis with longitudinal data and discuss its potential for improving clinical decision making.
Deep Ensembles on a Fixed Memory Budget: One Wide Network or Several Thinner Ones?
Chirkova, Nadezhda, Lobacheva, Ekaterina, Vetrov, Dmitry
One of the generally accepted views of modern deep learning is that increasing the number of parameters usually leads to better quality. The two easiest ways to increase the number of parameters is to increase the size of the network, e.g. width, or to train a deep ensemble; both approaches improve the performance in practice. In this work, we consider a fixed memory budget setting, and investigate, what is more effective: to train a single wide network, or to perform a memory split -- to train an ensemble of several thinner networks, with the same total number of parameters? We find that, for large enough budgets, the number of networks in the ensemble, corresponding to the optimal memory split, is usually larger than one. Interestingly, this effect holds for the commonly used sizes of the standard architectures. For example, one WideResNet-28-10 achieves significantly worse test accuracy on CIFAR-100 than an ensemble of sixteen thinner WideResNets: 80.6% and 82.52% correspondingly. We call the described effect the Memory Split Advantage and show that it holds for a variety of datasets and model architectures.
Know Your Clients' behaviours: a cluster analysis of financial transactions
Thompson, John R. J., Feng, Longlong, Reesor, R. Mark, Grace, Chuck
In Canada, financial advisors and dealers are required by provincial securities commissions and self-regulatory organizations--charged with direct regulation over investment dealers and mutual fund dealers--to respectively collect and maintain Know Your Client (KYC) information, such as their age or risk tolerance, for investor accounts. With this information, investors, under their advisor's guidance, make decisions on their investments which are presumed to be beneficial to their investment goals. Our unique dataset is provided by a financial investment dealer with over 50,000 accounts for over 23,000 clients. We use a modified behavioural finance recency, frequency, monetary model for engineering features that quantify investor behaviours, and machine learning clustering algorithms to find groups of investors that behave similarly. We show that the KYC information collected does not explain client behaviours, whereas trade and transaction frequency and volume are most informative. We believe the results shown herein encourage financial regulators and advisors to use more advanced metrics to better understand and predict investor behaviours.
Simulation-Based Inference for Global Health Decisions
de Witt, Christian Schroeder, Gram-Hansen, Bradley, Nardelli, Nantas, Gambardella, Andrew, Zinkov, Rob, Dokania, Puneet, Siddharth, N., Espinosa-Gonzalez, Ana Belen, Darzi, Ara, Torr, Philip, Baydin, Atılım Güneş
This is fomenting the development of comprehensive modelling The COVID-19 pandemic has highlighted the importance and simulation to support the design of health interventions of in-silico epidemiological modelling in predicting and policies, and to guide decision-making in a variety of the dynamics of infectious diseases to inform health system domains [22, 49]. For example, simulations health policy and decision makers about suitable prevention have provided valuable insight to deal with public health and containment strategies. Work in this setting problems such as tobacco consumption in New Zealand [50], involves solving challenging inference and control and diabetes and obesity in the US [58]. They have been problems in individual-based models of ever increasing used to explore policy options such as those in maternal and complexity. Here we discuss recent breakthroughs antenatal care in Uganda [44], and applied to evaluate health in machine learning, specifically in simulation-based reform scenarios such as predicting changes in access to inference, and explore its potential as a novel venue primary care services in Portugal [21]. Their applicability for model calibration to support the design and evaluation in informing the design of cancer screening programmes of public health interventions. To further stimulate has been also discussed [42, 23]. Recently, simulations have research, we are developing software interfaces that informed the response to the COVID-19 outbreak [19].
Simultaneous imputation and disease classification in incomplete medical datasets using Multigraph Geometric Matrix Completion (MGMC)
Vivar, Gerome, Kazi, Anees, Burwinkel, Hendrik, Zwergal, Andreas, Navab, Nassir, Ahmadi, Seyed-Ahmad
Large-scale population-based studies in medicine are a key resource towards better diagnosis, monitoring, and treatment of diseases. They also serve as enablers of clinical decision support systems, in particular Computer Aided Diagnosis (CADx) using machine learning (ML). Numerous ML approaches for CADx have been proposed in literature. However, these approaches assume full data availability, which is not always feasible in clinical data. To account for missing data, incomplete data samples are either removed or imputed, which could lead to data bias and may negatively affect classification performance. As a solution, we propose an end-to-end learning of imputation and disease prediction of incomplete medical datasets via Multigraph Geometric Matrix Completion (MGMC). MGMC uses multiple recurrent graph convolutional networks, where each graph represents an independent population model based on a key clinical meta-feature like age, sex, or cognitive function. Graph signal aggregation from local patient neighborhoods, combined with multigraph signal fusion via self-attention, has a regularizing effect on both matrix reconstruction and classification performance. Our proposed approach is able to impute class relevant features as well as perform accurate classification on two publicly available medical datasets. We empirically show the superiority of our proposed approach in terms of classification and imputation performance when compared with state-of-the-art approaches. MGMC enables disease prediction in multimodal and incomplete medical datasets. These findings could serve as baseline for future CADx approaches which utilize incomplete datasets.
Echo State Networks trained by Tikhonov least squares are L2({\mu}) approximators of ergodic dynamical systems
Hart, Allen G, Hook, James L, Dawes, Jonathan H P
Echo State Networks (ESNs) are a class of single-layer recurrent neural networks with randomly generated internal weights, and a single layer of tuneable outer weights, which are usually trained by regularised linear least squares regression. Remarkably, ESNs still enjoy the universal approximation property despite the training procedure being entirely linear. In this paper, we prove that an ESN trained on a sequence of scalar observations from an ergodic dynamical system (with invariant measure {\mu}) using Tikhonov least squares will approximate future observations of the dynamical system in the L2({\mu}) norm. We call this the ESN Training Theorem. We demonstrate the theory numerically by training an ESN using Tikhonov least squares on a sequence of scalar observations of the Lorenz system, and compare the invariant measure of these observations with the invariant measure of the future predictions of the autonomous ESN.
Thompson Sampling for Combinatorial Semi-bandits with Sleeping Arms and Long-Term Fairness Constraints
Huang, Zhiming, Xu, Yifan, Hu, Bingshan, Wang, Qipeng, Pan, Jianping
We study the combinatorial sleeping multi-armed semi-bandit problem with long-term fairness constraints~(CSMAB-F). To address the problem, we adopt Thompson Sampling~(TS) to maximize the total rewards and use virtual queue techniques to handle the fairness constraints, and design an algorithm called \emph{TS with beta priors and Bernoulli likelihoods for CSMAB-F~(TSCSF-B)}. Further, we prove TSCSF-B can satisfy the fairness constraints, and the time-averaged regret is upper bounded by $\frac{N}{2\eta} + O\left(\frac{\sqrt{mNT\ln T}}{T}\right)$, where $N$ is the total number of arms, $m$ is the maximum number of arms that can be pulled simultaneously in each round~(the cardinality constraint) and $\eta$ is the parameter trading off fairness for rewards. By relaxing the fairness constraints (i.e., let $\eta \rightarrow \infty$), the bound boils down to the first problem-independent bound of TS algorithms for combinatorial sleeping multi-armed semi-bandit problems. Finally, we perform numerical experiments and use a high-rating movie recommendation application to show the effectiveness and efficiency of the proposed algorithm.
Evo* 2020 -- Late-Breaking Abstracts Volume
Mora, A. M., Esparcia-Alcázar, A. I.
This volume contains the Late-Breaking Abstracts submitted to the Evo* 2020 Conference, that took place online, from 15 to 17 of April 2020. These papers where presented as short talks and also at the poster session of the conference together with other regular submissions. All of them present ongoing research and preliminary results investigating on the application of different approaches of Bioinspired Methods (mainly Evolutionary Computation) to different problems, most of them real world ones.
Rolling Horizon NEAT for General Video Game Playing
Perez-Liebana, Diego, Alam, Muhammad Sajid, Gaina, Raluca D.
This paper presents a new Statistical Forward Planning (SFP) method, Rolling Horizon NeuroEvolution of Augmenting Topologies (rhNEAT). Unlike traditional Rolling Horizon Evolution, where an evolutionary algorithm is in charge of evolving a sequence of actions, rhNEAT evolves weights and connections of a neural network in real-time, planning several steps ahead before returning an action to execute in the game. Different versions of the algorithm are explored in a collection of 20 GVGAI games, and compared with other SFP methods and state of the art results. Although results are overall not better than other SFP methods, the nature of rhNEAT to adapt to changing game features has allowed to establish new state of the art records in games that other methods have traditionally struggled with. The algorithm proposed here is general and introduces a new way of representing information within rolling horizon evolution techniques.
Cognitive Amplifier for Internet of Things
Huang, Bing, Bouguettaya, Athman, Neiat, Azadeh Ghari
With the emergence of IoT, there is a rising interest in applying Internet of Things (IoT) technology in the smart homes for making occupants' life more convenient. The convenience is underpinned by the principle of the least effort, i.e. the premise that humans would usually want to achieve goals with the least cognitive and physical efforts [2]. IoT refers to the networked interconnection of everyday things, which are augmented with capabilities such as sensing, actuating, and communication [21]. The availability of IoT devices including switch sensors, infrared motion sensors, pressure sensor, wearable sensors, accelerators, temperature, humidity, and light sensors have the potential to realize the convenience. It is a challenge that IoT devices are highly diverse in supporting infrastructure such as different programming language and communication protocols [5].