Asia
How China could beat the West in the deadly race for AI weapons
Chinese People's Liberation Army (PLA) Air Force officers march past Tiananmen Square in a show of military strength Last month, some of the biggest names in technology signed a pledge promising not to develop lethal autonomous weapons. Coming just after the recent employee-led protest over Google's Project Maven, some have praised these initiatives as ethical and moral victories. For Sandro Gaycken, a senior advisor to Nato, such initiatives are supremely complacent and risk granting authoritarian states an asymmetric advantage. "These naive hippy developers from Silicon Valley don't understand – the CIA should force them," says Gaycken, founder of the digital society institute at ESMT, a Berlin-based business school. Gaycken's hard advice reveals a schism emerging in the future development of AI for military purposes. On the one side are those that believe pursuing the development of military AI will lead to an unstoppable arms race. On the other side, people like Gaycken believe the AI arms-race has already begun.
New design of the Rubik's cube lets you battle other players online using Bluetooth
One of the world's oldest and most popular toys is getting a face-lift. Israel-based startup Particula has unveiled its spin on the Rubik's cube, dubbed the GoCube, that can connect to your phone and enables users to play against other people. It marks a major step up from when the original Rubik's cube, developed by Hungarian sculptor Erno Rubik, was first released in 1974. Since then, over 350 million Rubik's cubes have been sold worldwide. Israel-based startup Particula has unveiled its spin on the Rubik's cube, dubbed the GoCube (pictured), that can connect to your phone and enables users to play against other people The GoCube syncs up with smartphones and tablets using a Bluetooth connection, giving users access to the Battle feature, which lets them'play friends (or enemies) across the world, according to Particula.
Why Google's censored search engine for China is an ethical minefield
The Great Firewall of China is the largest-scale internet censorship operation in the world. The Chinese state says the firewall is there to promote societal harmony within an increasing population of billions of people. It considers the internet in China as part of its sovereign territory. Eight years ago, Google withdrew from China, pulling its search and other services out because of country's limits to freedom of speech. But it is now planning to relaunch a heavily censored version of its services in China, according to a whistleblower who spoke to online news website The Intercept.
Policy Optimization as Wasserstein Gradient Flows
Zhang, Ruiyi, Chen, Changyou, Li, Chunyuan, Carin, Lawrence
Policy optimization is a core component of reinforcement learning (RL), and most existing RL methods directly optimize parameters of a policy based on maximizing the expected total reward, or its surrogate. Though often achieving encouraging empirical success, its underlying mathematical principle on {\em policy-distribution} optimization is unclear. We place policy optimization into the space of probability measures, and interpret it as Wasserstein gradient flows. On the probability-measure space, under specified circumstances, policy optimization becomes a convex problem in terms of distribution optimization. To make optimization feasible, we develop efficient algorithms by numerically solving the corresponding discrete gradient flows. Our technique is applicable to several RL settings, and is related to many state-of-the-art policy-optimization algorithms. Empirical results verify the effectiveness of our framework, often obtaining better performance compared to related algorithms.
Does Hamiltonian Monte Carlo mix faster than a random walk on multimodal densities?
Mangoubi, Oren, Pillai, Natesh S., Smith, Aaron
Hamiltonian Monte Carlo (HMC) is a very popular and generic collection of Markov chain Monte Carlo (MCMC) algorithms. One explanation for the popularity of HMC algorithms is their excellent performance as the dimension $d$ of the target becomes large: under conditions that are satisfied for many common statistical models, optimally-tuned HMC algorithms have a running time that scales like $d^{0.25}$. In stark contrast, the running time of the usual Random-Walk Metropolis (RWM) algorithm, optimally tuned, scales like $d$. This superior scaling of the HMC algorithm with dimension is attributed to the fact that it, unlike RWM, incorporates the gradient information in the proposal distribution. In this paper, we investigate a different scaling question: does HMC beat RWM for highly $\textit{multimodal}$ targets? We find that the answer is often $\textit{no}$. We compute the spectral gaps for both the algorithms for a specific class of multimodal target densities, and show that they are identical. The key reason is that, within one mode, the gradient is effectively ignorant about other modes, thus negating the advantage the HMC algorithm enjoys in unimodal targets. We also give heuristic arguments suggesting that the above observation may hold quite generally. Our main tool for answering this question is a novel simple formula for the conductance of HMC using Liouville's theorem. This result allows us to compute the spectral gap of HMC algorithms, for both the classical HMC with isotropic momentum and the recent Riemannian HMC, for multimodal targets.
Fuzzy Clustering to Identify Clusters at Different Levels of Fuzziness: An Evolutionary Multi-Objective Optimization Approach
Gupta, Avisek, Datta, Shounak, Das, Swagatam
Fuzzy clustering methods identify naturally occurring clusters in a dataset, where the extent to which different clusters are overlapped can differ. Most methods have a parameter to fix the level of fuzziness. However, the appropriate level of fuzziness depends on the application at hand. This paper presents Entropy $c$-Means (ECM), a method of fuzzy clustering that simultaneously optimizes two contradictory objective functions, resulting in the creation of fuzzy clusters with different levels of fuzziness. This allows ECM to identify clusters with different degrees of overlap. ECM optimizes the two objective functions using two multi-objective optimization methods, Non-dominated Sorting Genetic Algorithm II (NSGA-II), and Multiobjective Evolutionary Algorithm based on Decomposition (MOEA/D). We also propose a method to select a suitable trade-off clustering from the Pareto front. Experiments on challenging synthetic datasets as well as real-world datasets show that ECM leads to better cluster detection compared to the conventional fuzzy clustering methods as well as previously used multi-objective methods for fuzzy clustering.
A Survey on Surrogate Approaches to Non-negative Matrix Factorization
Motivated by applications in hyperspectral imaging we investigate methods for approximating a high-dimensional non-negative matrix $\mathbf{\mathit{Y}}$ by a product of two lower-dimensional, non-negative matrices $\mathbf{\mathit{K}}$ and $\mathbf{\mathit{X}}.$ This so-called non-negative matrix factorization is based on defining suitable Tikhonov functionals, which combine a discrepancy measure for $\mathbf{\mathit{Y}}\approx\mathbf{\mathit{KX}}$ with penalty terms for enforcing additional properties of $\mathbf{\mathit{K}}$ and $\mathbf{\mathit{X}}$. The minimization is based on alternating minimization with respect to $\mathbf{\mathit{K}}$ or $\mathbf{\mathit{X}}$, where in each iteration step one replaces the original Tikhonov functional by a locally defined surrogate functional. The choice of surrogate functionals is crucial: It should allow a comparatively simple minimization and simultaneously its first order optimality condition should lead to multiplicative update rules, which automatically preserve non-negativity of the iterates. We review the most standard construction principles for surrogate functionals for Frobenius-norm and Kullback-Leibler discrepancy measures. We extend the known surrogate constructions by a general framework, which allows to add a large variety of penalty terms. The paper finishes by deriving the corresponding alternating minimization schemes explicitely and by applying these methods to MALDI imaging data.
A Hybrid Recommender System for Patient-Doctor Matchmaking in Primary Care
Han, Qiwei, Ji, Mengxin, de Troya, Inigo Martinez de Rituerto, Gaur, Manas, Zejnilovic, Leid
Primary care serves as patients' first point of contact with the healthcare system and is a continuing focal point of comprehensive, accessible, and community-based care [1]. More than just a gate-keeping process for specialist referrals, it has been widely recognized for its focus on caring for the longterm health of patients rather than solely for treating specific diseases or conditions. As such, primary care helps deliver more equitable health outcomes across populations and meets 80-90% of individuals' health needs throughout their lives [2]. To this end, a recent special report from the Economist stated that "good primary care is an essential precondition for a decent healthcare system" [3]. The World Health Organization (WHO) emphasized several defining features for effective and socially productive primary care, including comprehensiveness, person-centeredness, and continuity of care [4]. In particular, person-centeredness refers to the "clinical method of participatory democracy" that allows patients to participate in decisions that affect their health.
On feature selection and evaluation of transportation mode prediction strategies
Etemad, Mohammad, Junior, Amilcar Soares, Matwin, Stan
Transportation modes prediction is a fundamental task for decision making in smart cities and traffic management systems. Traffic policies designed based on trajectory mining can save money and time for authorities and the public. It may reduce the fuel consumption and commute time and moreover, may provide more pleasant moments for residents and tourists. Since the number of features that may be used to predict a user transportation mode can be substantial, finding a subset of features that maximizes a performance measure is worth investigating. In this work, we explore wrapper and information retrieval methods to find the best subset of trajectory features. After finding the best classifier and the best feature subset, our results were compared with two related papers that applied deep learning methods and the results showed that our framework achieved better performance. Furthermore, two types of cross-validation approaches were investigated, and the performance results show that the random cross-validation method provides optimistic results.
$\alpha$-Approximation Density-based Clustering of Multi-valued Objects
Zhilin Zhang Abstract Multi-valued data are commonly found in many real applications. During the process of clustering multi-valued data, most existing methods use sampling or aggregation mechanisms that cannot reflect the real distribution of objects and their instances and thus fail to obtain high-quality clusters. In this paper, a concept ofα -approximation distance is introduced to measure the connectivity between multi-valued objects by taking account of the distribution of the instances. An α -approximation density-based clustering algorithm (DBCMO) is proposed to efficiently cluster the multi-valued objects by using global and local R* tree structures. To speed up the algorithm, four pruning rules on the tree structures are implemented. Empirical studies on synthetic and real datasets demonstrate that DBCMO can efficiently and effectively discover the multi-valued object clusters. A comparison with two existing methods further shows that DBCMO can better handle a continuous decrease in the cluster density and detect clusters of varying density. Keywords Multi-valued objects· α -Approximation· Density-based· Clustering 1 Introduction Multi-valued data (Zhang et al. 2010), including multi-instance data and uncertain data, are commonly found in many real applications. The check-in data of location-based social networks are one example. Each user is an object, and he/she can have multiple check-in records associated with different temporal and spatial information. The observation data of dynamic objects, such as seismic activity, sea floor bathymetry, and sea height, are other examples. Since the states of observed objects change constantly, the limited observation data can only reveal the objects' states with a certain probability. The clustering of multi-valued objects is the process of grouping objects into different partitions based on similarity measurements or connectivity calculations. Based on the mechanism used for measuring similarity or connectivity, the clustering algorithms for multi-valued objects can be divided into two main categories: aggregation-based clustering and sampling-based clustering. Aggregation-based clustering methodology first transfers the multi-valued objects into single-valued objects with an aggregation function (e.g. the mean). After that, various traditional clustering algorithms can be applied directly. Sampling-based methods obtain a sequence of sample points for each object using sampling techniques. And then the distance density function or the expected distance of two objects can be computed with the multiple discrete distance values from the samples. Both aggregation and sampling are useful in reducing computational cost, especially when there is large number of values for objects. However, determination of a proper aggregation function or sampling strategy is not trivial.