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Multi-view Subspace Clustering via Partition Fusion
Lv, Juncheng, Kang, Zhao, Wang, Boyu, Ji, Luping, Xu, Zenglin
Multi-view clustering is an important approach to analyze multi-view data in an unsupervised way. Among various methods, the multi-view subspace clustering approach has gained increasing attention due to its encouraging performance. Basically, it integrates multi-view information into graphs, which are then fed into spectral clustering algorithm for final result. Orthogonal to current work, we propose to fuse multi-view information in a partition space, which enhances the robustness of Multi-view clustering. Specifically, we generate multiple partitions and integrate them to find the shared partition. The proposed model unifies graph learning, generation of basic partitions, and view weight learning. We have conducted comprehensive experiments on benchmark datasets and our empirical results verify the effectiveness and robustness of our approach. Introduction In many real-world problems, data are collected from different sources in diverse domains or described by various feature collectors [1, 2, 3, 4, 5]. To process these kinds of data, a number of multi-view learning algorithms have been developed [8, 9, 10, 11, 12].
Towards Understanding the Spectral Bias of Deep Learning
Cao, Yuan, Fang, Zhiying, Wu, Yue, Zhou, Ding-Xuan, Gu, Quanquan
An intriguing phenomenon observed during training neural networks is the spectral bias, where neural networks are biased towards learning less complex functions. The priority of learning functions with low complexity might be at the core of explaining generalization ability of neural network, and certain efforts have been made to provide theoretical explanation for spectral bias. However, there is still no satisfying theoretical result justifying the underlying mechanism of spectral bias. In this paper, we give a comprehensive and rigorous explanation for spectral bias and relate it with the neural tangent kernel function proposed in recent work. We prove that the training process of neural networks can be decomposed along different directions defined by the eigenfunctions of the neural tangent kernel, where each direction has its own convergence rate and the rate is determined by the corresponding eigenvalue. We then provide a case study when the input data is uniformly distributed over the unit sphere, and show that lower degree spherical harmonics are easier to be learned by over-parameterized neural networks.
On Classifying Sepsis Heterogeneity in the ICU: Insight Using Machine Learning
Ibrahim, Zina, Wu, Honghan, Hamoud, Ahmed, Stappen, Lukas, Dobson, Richard, Agarossi, Andrea
Tel: 44 (0) 758 285 9501 Mesh Term s Machine Learning, Sepsis Syndrome Word Count: 2,000 AB STRACT Current machine learning models aiming to predict sepsis from Electronic Health Records (EHR) do not account for the heterogeneity of the condition, despite its e me r ging importance in prognosis and treatment. This work demonstrate s the added value of stratifying the types of organ dysfunction observed in patients who develop sepsis in the ICU in improving the ability to recognise patients at risk of sepsis from their EHR data. Using an ICU dataset of 13,728 records, we identify clinically significant sepsis subpopulations with distinct organ dysfunction patterns . Classification experiments using Random Forest, Gradient Boost Trees and Support Vector Machines, aiming to distinguish patients who develop sepsis in the ICU from those who do not, show that features selected using sepsis subpopulations as background knowledge yield a superior performance regardless of the classification model used. Our findings can steer mach ine learning efforts towards more personalised models for complex conditions including sepsis.
A Quasi-Newton Method Based Vertical Federated Learning Framework for Logistic Regression
Yang, Kai, Fan, Tao, Chen, Tianjian, Shi, Yuanming, Yang, Qiang
Data privacy and security becomes a major concern in building machine learning models from different data providers. Federated learning shows promise by leaving data at providers locally and exchanging encrypted information. This paper studies the vertical federated learning structure for logistic regression where the data sets at two parties have the same sample IDs but own disjoint subsets of features. Existing frameworks adopt the first-order stochastic gradient descent algorithm, which requires large number of communication rounds. To address the communication challenge, we propose a quasi-Newton method based vertical federated learning framework for logistic regression under the additively homomorphic encryption scheme. Our approach can considerably reduce the number of communication rounds with a little additional communication cost per round. Numerical results demonstrate the advantages of our approach over the first-order method.
A Contextual-Bandit Approach to Online Learning to Rank for Relevance and Diversity
Li, Chang, Feng, Haoyun, de Rijke, Maarten
Online learning to rank (LTR) focuses on learning a policy from user interactions that builds a list of items sorted in decreasing order of the item utility. It is a core area in modern interactive systems, such as search engines, recommender systems, or conversational assistants. Previous online LTR approaches either assume the relevance of an item in the list to be independent of other items in the list or the relevance of an item to be a submodular function of the utility of the list. The former type of approach may result in a list of low diversity that has relevant items covering the same aspects, while the latter approaches may lead to a highly diversified list but with some non-relevant items. In this paper, we study an online LTR problem that considers both item relevance and topical diversity. We assume cascading user behavior, where a user browses the displayed list of items from top to bottom and clicks the first attractive item and stops browsing the rest. We propose a hybrid contextual bandit approach, called CascadeHybrid, for solving this problem. CascadeHybrid models item relevance and topical diversity using two independent functions and simultaneously learns those functions from user click feedback. We derive a gap-free bound on the n-step regret of CascadeHybrid. We conduct experiments to evaluate CascadeHybrid on the MovieLens and Yahoo music datasets. Our experimental results show that CascadeHybrid outperforms the baselines on both datasets.
Ontologies for the Virtual Materials Marketplace
Horsch, Martin Thomas, Chiacchiera, Silvia, Seaton, Michael A., Todorov, Ilian T., Šindelka, Karel, Lísal, Martin, Andreon, Barbara, Kaiser, Esteban Bayro, Mogni, Gabriele, Goldbeck, Gerhard, Kunze, Ralf, Summer, Georg, Fiseni, Andreas, Brüning, Hauke, Schiffels, Peter, Cavalcanti, Welchy Leite
The Virtual Materials Marketplace (VIMMP) project, which develops an open platform for providing and accessing services related to materials modelling, is presented with a focus on its ontology development and data technology aspects. Within VIMMP, a system of marketplace-level ontologies is developed to characterize services, models, and interactions between users; the European Materials and Modelling Ontology (EMMO), which is based on mereotopology following Varzi and semiotics following Peirce, is employed as a top-level ontology. The ontologies are used to annotate data that are stored in the ZONTAL Space component of VIMMP and to support the ingest and retrieval of data and metadata at the VIMMP marketplace frontend.
Towards Building a Multilingual Sememe Knowledge Base: Predicting Sememes for BabelNet Synsets
Qi, Fanchao, Chang, Liang, Sun, Maosong, Ouyang, Sicong, Liu, Zhiyuan
A sememe is defined as the minimum semantic unit of human languages. Sememe knowledge bases (KBs), which contain words annotated with sememes, have been successfully applied to many NLP tasks. However, existing sememe KBs are built on only a few languages, which hinders their widespread utilization. To address the issue, we propose to build a unified sememe KB for multiple languages based on BabelNet, a multilingual encyclopedic dictionary. We first build a dataset serving as the seed of the multilingual sememe KB. It manually annotates sememes for over $15$ thousand synsets (the entries of BabelNet). Then, we present a novel task of automatic sememe prediction for synsets, aiming to expand the seed dataset into a usable KB. We also propose two simple and effective models, which exploit different information of synsets. Finally, we conduct quantitative and qualitative analyses to explore important factors and difficulties in the task. All the source code and data of this work can be obtained on https://github.com/thunlp/BabelNet-Sememe-Prediction.
A Dataset Schema for Cooperative Learning from Demonstration in Multi-robots Systems
Simões, Marco A. C., da Silva, Robson Marinho, Nogueira, Tatiane
To achieve these common goals, agents in a MAS should be capable of interacting with other agents, not simply by exchanging data, but by engaging as in social activities, such as those people participate in their daily lives: cooperation, coordination, negotiation, and the like. In MASs, agents are assumed to be autonomous - capable of making independent decisions about to do in order to satisfy their design objectives, and thus they need mechanisms that allow them to synchronize and to coordinate their activities at run time [31]. Although one of the main issues in MASs is the agents' coordination structure, this is not hard-wired at design time, as MASs are typically in standard concurrent/distributed systems. One well-known strategy for coordination in MAS is the design of multi-agent coordinated plans [7][35][36][33][14] that include, not only usual agents' actions defined by their effectors, but also communication actions to achieve the necessary synchronization and coordination. To represent communication actions, some specific languages were created, e.g.
ALFRED: A Benchmark for Interpreting Grounded Instructions for Everyday Tasks
Shridhar, Mohit, Thomason, Jesse, Gordon, Daniel, Bisk, Yonatan, Han, Winson, Mottaghi, Roozbeh, Zettlemoyer, Luke, Fox, Dieter
We present ALFRED (Action Learning From Realistic Environments and Directives), a benchmark for learning a mapping from natural language instructions and egocentric vision to sequences of actions for household tasks. Long composition rollouts with non-reversible state changes are among the phenomena we include to shrink the gap between research benchmarks and real-world applications. ALFRED consists of expert demonstrations in interactive visual environments for 25k natural language directives. These directives contain both high-level goals like "Rinse off a mug and place it in the coffee maker." and low-level language instructions like "Walk to the coffee maker on the right." ALFRED tasks are more complex in terms of sequence length, action space, and language than existing vision-and-language task datasets. We show that a baseline model designed for recent embodied vision-and-language tasks performs poorly on ALFRED, suggesting that there is significant room for developing innovative grounded visual language understanding models with this benchmark.
A Simulation Model for Pedestrian Crowd Evacuation Based on Various AI Techniques
Muhammed, Danial A., Saeed, Soran A. M., Rashid, Tarik A.
This paper attempts to design an intelligent simulation model for pedestrian crowd evacuation. For this purpose, the cellular automata (CA) was fully integrated with fuzzy logi c, the k th nearest neighbors ( K NN), and some statistical equations. In this model, each pedestrian was assigned a specific speed, according to his/her physical, biological and emotional features. The emergency behavior and evacuation efficiency of each pedestrian were evaluated by coupling his/her speed with various elements, such as environment, pedestrian distribution and familiarity with the exits. These elements all have great impacts on the ev acuation process. Several experiments were carried out to verify the performance of the model in different emergency scenarios. The results show that the proposed model can predict the evacuation time and emergency behavior in various types of building int eriors and pedestrian distributions. The research provides a good reference to the design of building evacuation systems.