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Generic Ontology Design Patterns at Work
Krieg-Brückner, Bernd, Mossakowski, Till, Neuhaus, Fabian
Generic Ontology Design Patterns, GODPs, are defined in Generic DOL, an extension of DOL, the Distributed Ontology, Model and Specification Language, and implemented using Heterogeneous Tool Set. Parameters such as classes, properties, individuals, or whole ontologies may be instantiated with arguments in a host ontology. The potential of Generic DOL is illustrated with GODPs for an example from the literature, namely the Role design pattern. We also discuss how larger GODPs may be composed by instantiating smaller GODPs.
Modeling AGI Safety Frameworks with Causal Influence Diagrams
Everitt, Tom, Kumar, Ramana, Krakovna, Victoria, Legg, Shane
One of the primary goals of AI research is the development of artificial agents that can exceed human performance on a wide range of cognitive tasks, in other words, artificial general intelligence (AGI). Although the development of AGI has many potential benefits, there are also many safety concerns that have been raised in the literature [Bostrom, 2014; Everitt et al., 2018; Amodei et al., 2016]. Various approaches for addressing AGI safety have been proposed [Leike et al., 2018; Christiano et al., 2018; Irving et al., 2018; Hadfield-Menell et al., 2016; Everitt, 2018], often presented as a modification of the reinforcement learning (RL) framework, or a new framework altogether. Understanding and comparing different frameworks for AGI safety can be difficult because they build on differing concepts and assumptions. For example, both reward modeling [Leike et al., 2018] and cooperative inverse RL [Hadfield-Menell et al., 2016] are frameworks for making an agent learn the preferences of a human user, but what are the key differences between them?
Cooperative Lane Changing via Deep Reinforcement Learning
Wang, Guan, Hu, Jianming, Li, Zhiheng, Li, Li
In this paper, we study how to learn an appropriate lane changing strategy for autonomous vehicles by using deep reinforcement learning. We show that the reward of the system should consider the overall traffic efficiency instead of the travel efficiency of an individual vehicle. In summary, cooperation leads to a more harmonic and efficient traffic system rather than competition
Customer Segmentation of Wireless Trajectory Data
Karlsen, Matthew R, Moschoyiannis, Sotiris K.
Wireless trajectory data consists of a number of (time, point) entries where each point is associated with a particular wireless device (WAP or BLE beacon) tied to a location identifier, such as a place name. A trajectory relates to a particular mobile device. Such data can be clustered `semantically' to identify similar trajectories, where similarity relates to non-geographic characteristics such as the type of location visited. Here we present a new approach to semantic trajectory clustering for such data. The approach is applicable to interpreting data that does not contain geographical coordinates, and thus contributes to the current literature on semantic trajectory clustering. The literature does not appear to provide such an approach, instead focusing on trajectory data where latitude and longitude data is available. We apply the techniques developed above in the context of the Onward Journey Planner Application, with the motivation of providing on-line recommendations for onward journey options in a context-specific manner. The trajectories analysed indicate commute patterns on the London Underground. Points are only recorded for communication with WAP and BLE beacons within the rail network. This context presents additional challenge since the trajectories are `truncated', with no true origin and destination details. In the above context we find that there are a range of travel patterns in the data, without the existence of distinct clusters. Suggestions are made concerning how to approach the problem of provision of on-line recommendations with such a data set. Thoughts concerning the related problem of prediction of journey route and destination are also provided.
Data Cleansing for Models Trained with SGD
Hara, Satoshi, Nitanda, Atsushi, Maehara, Takanori
Data cleansing is a typical approach used to improve the accuracy of machine learning models, which, however, requires extensive domain knowledge to identify the influential instances that affect the models. In this paper, we propose an algorithm that can suggest influential instances without using any domain knowledge. With the proposed method, users only need to inspect the instances suggested by the algorithm, implying that users do not need extensive knowledge for this procedure, which enables even non-experts to conduct data cleansing and improve the model. The existing methods require the loss function to be convex and an optimal model to be obtained, which is not always the case in modern machine learning. To overcome these limitations, we propose a novel approach specifically designed for the models trained with stochastic gradient descent (SGD). The proposed method infers the influential instances by retracing the steps of the SGD while incorporating intermediate models computed in each step. Through experiments, we demonstrate that the proposed method can accurately infer the influential instances. Moreover, we used MNIST and CIFAR10 to show that the models can be effectively improved by removing the influential instances suggested by the proposed method.
Quantum-Inspired Support Vector Machine
Ding, Chen, Bao, Tian-Yi, Huang, He-Liang
Support vector machine (SVM) is a particularly powerful and flexible supervised learning model that analyze data for both classification and regression, whose usual complexity scales polynomially with the dimension and number of data points. Inspired by the quantum SVM, we present a quantum-inspired classical algorithm for SVM using fast sampling techniques. In our approach, we develop a general method to approximately calculate the kernel function and make classification via carefully sampling the data matrix, thus our approach can be applied to various types of SVM, such as linear SVM, poly-kernel SVM and soft SVM. Theoretical analysis shows one can find the supported hyperplanes on a data set which we have sampling access, and thus make classification with arbitrary success probability in logarithmic runtime, matching the runtime of the quantum SVM.
Bayesian Optimisation over Multiple Continuous and Categorical Inputs
Ru, Binxin, Alvi, Ahsan S., Nguyen, Vu, Osborne, Michael A., Roberts, Stephen J
Efficient optimisation of black-box problems that comprise both continuous and categorical inputs is important, yet poses significant challenges. We propose a new approach, Continuous and Categorical Bayesian Optimisation (CoCaBO), which combines the strengths of multi-armed bandits and Bayesian optimisation to select values for both categorical and continuous inputs. We model this mixed-type space using a Gaussian Process kernel, designed to allow sharing of information across multiple categorical variables, each with multiple possible values; this allows CoCaBO to leverage all available data efficiently. We extend our method to the batch setting and propose an efficient selection procedure that dynamically balances exploration and exploitation whilst encouraging batch diversity. We demonstrate empirically that our method outperforms existing approaches on both synthetic and real-world optimisation tasks with continuous and categorical inputs.
A multi-task U-net for segmentation with lazy labels
Ke, Rihuan, Bugeau, Aurélie, Papadakis, Nicolas, Schuetz, Peter, Schönlieb, Carola-Bibiane
The need for labour intensive pixel-wise annotation is a major limitation of many fully supervised learning methods for image segmentation. In this paper, we propose a deep convolutional neural network for multi-class segmentation that circumvents this problem by being trainable on coarse data labels combined with only a very small number of images with pixel-wise annotations. We call this new labelling strategy 'lazy' labels. Image segmentation is then stratified into three connected tasks: rough detection of class instances, separation of wrongly connected objects without a clear boundary, and pixel-wise segmentation to find the accurate boundaries of each object. These problems are integrated into a multitask learning framework and the model is trained end-to-end in a semi-supervised fashion. The method is applied on a dataset of food microscopy images. We show that the model gives accurate segmentation results even if exact boundary labels are missing for a majority of the annotated data. This allows more flexibility and efficiency for training deep neural networks that are data hungry in a practical setting where manual annotation is expensive, by collecting more lazy (rough) annotations than precisely segmented images.
Effective degrees of freedom for surface finish defect detection and classification
Arnqvist, Natalya Pya, Ngendangenzwa, Blaise, Lindahl, Eric, Nilsson, Leif, Yu, Jun
One of the primary concerns of product quality control in the automotive industry is an automated detection of defects of small sizes on specular car body surfaces. A new statistical learning approach is presented for surface finish defect detection based on spline smoothing method for feature extraction and $k$-nearest neighbour probabilistic classifier. Since the surfaces are specular, structured lightning reflection technique is applied for image acquisition. Reduced rank cubic regression splines are used to smooth the pixel values while the effective degrees of freedom of the obtained smooths serve as components of the feature vector. A key advantage of the approach is that it allows reaching near zero misclassification error rate when applying standard learning classifiers. We also propose probability based performance evaluation metrics as alternatives to the conventional metrics. The usage of those provides the means for uncertainty estimation of the predictive performance of a classifier. Experimental classification results on the images obtained from the pilot system located at Volvo GTO Cab plant in Ume{\aa}, Sweden, show that the proposed approach is much more efficient than the compared methods.
Pushing the Limits of Importance Sampling through Iterative Moment Matching
Paananen, Topi, Piironen, Juho, Bürkner, Paul-Christian, Vehtari, Aki
The accuracy of an integral approximation via Monte Carlo sampling depends on the distribution of the integrand and the existence of its moments. In importance sampling, the choice of the proposal distribution markedly affects the existence of these moments and thus the accuracy of the obtained integral approximation. In this work, we present a method for improving the proposal distribution that applies to complicated distributions which are not available in closed form. The method iteratively matches the moments of a sample from the proposal distribution to their importance weighted moments, and is applicable to both standard importance sampling and self-normalized importance sampling. We apply the method to Bayesian leave-one-out cross-validation and show that it can significantly improve the accuracy of model assessment compared to regular Monte Carlo sampling or importance sampling when there are influential observations. We also propose a diagnostic method that can estimate the convergence rate of any Monte Carlo estimator from a finite random sample.