老年人跌倒检测算法的研究现状

近些年,老年人的健康问题越来越受到重视,跌倒作为影响老年人健康安全问题的主要原因之一,其研究热度一直居高不下,高质量的跌倒检测算法层出不穷.总结了跌倒检测的研究意义和现有的热门研究方法,分别从单一算法和混合算法的角度概述基于阈值、机器学习与深度学习三个方面的跌倒检测算法,介绍各算法的检测方式、判定方式、总体性能和各类单...     

不平衡数据分类方法综述

随着信息技术的快速发展,各领域的数据正以前所未有的速度产生并被广泛收集和存储,如何实现数据的智能化处理从而利用数据中蕴含的有价值信息已成为理论和应用的研究热点.数据分类作为一种基础的数据处理方法,已广泛应用于数据的智能化处理.传统分类方法通常假设数据类别分布均衡且错分代价相等,然而,现实中的数据通常具有不平衡特性,即某一类的样本数量要小于其他类的样本数量,且少数类具有更高错分代价.当利用传统的分类算法处理不平衡数据时,由于多数类和少数类在数量上的倾斜,以总体分类精度最大为目标会使得分类模型偏向于多数类而忽略少数类,造成少数类的分类精度较低.如何针对不平衡数据分类问题设计分类算法,同时保证不平衡数据中多数类与少数类的分类精度,已成为机器学习领域的研究热点,并相继出现了一系列优秀的不平衡数据分类方法.鉴于此,对现有的不平衡数据分类方法给出较为全面的梳理,从数据预处理层面、特征层面和分类算法层面总结和比较现有的不平衡数据分类方法,并结合当下机器学习的研究热点,探讨不平衡数据分类方法存在的挑战.最后展望不平衡数据分类未来的研究方向.     

The use of machine learning and deep learning algorithms in functional magnetic resonance imaging—A systematic review

Functional Magnetic Resonance Imaging (fMRI) is presently one of the most popular techniques for analysing the dynamic states in brain images using various kinds of algorithms. From the last decade, there is an exponential rise in the use of the machine and deep learning algorithms of artificial intelligence for analysing fMRI data. However, it is a big challenge for every researcher to choose a suitable machine or deep learning algorithm for analysing fMRI data due to the availability of a large number of algorithms in the literature. It takes much time for each researcher to know about the various approaches and algorithms which are in use for fMRI data. This paper provides a review in a systematic manner for the present literature of fMRI data that makes use of the machine and deep learning algorithms. The major goals of this review paper are to (a) identify machine learning and deep learning research trends for the implementation of fMRI; (b) identify usage of Machine Learning Algorithms and deep learning in fMRI, and (c) help new researchers based on fMRI to put their new findings appropriately in existing domain of fMRI research. The results of this systematic review identified various fMRI studies and classified them based on fMRI types, mental diseases, use of machine learning and deep learning algorithms. The authors have provided the studies with the best performance of machine learning and deep learning algorithms used in fMRI. The authors believe that this systematic review will help incoming researchers on fMRI in their future works.     

Data properties and the performance of sentiment classification for electronic commerce applications

Sentiment classification has played an important role in various research area including e-commerce applications and a number of advanced Computational Intelligence techniques including machine learning and computational linguistics have been proposed in the literature for improved sentiment classification results. While such studies focus on improving performance with new techniques or extending existing algorithms based on previously used dataset, few studies provide practitioners with insight on what techniques are better for their datasets that have different properties. This paper applies four different sentiment classification techniques from machine learning (Naïve Bayes, SVM and Decision Tree) and sentiment orientation approaches to datasets obtained from various sources (IMDB, Twitter, Hotel review, and Amazon review datasets) to learn how different data properties including dataset size, length of target documents, and subjectivity of data affect the performance of those techniques. The results of computational experiments confirm the sensitivity of the techniques on data properties including training data size, the document length and subjectivity of training /test data in the improvement of performances of techniques. The theoretical and practical implications of the findings are discussed.     

特征选择方法综述

特征选择作为一个数据预处理过程,在数据挖掘、模式识别和机器学习中有着重要地位。通过特征选择,可以降低问题的复杂度,提高学习算法的预测精度、鲁棒性和可解释性。介绍特征选择方法框架,重点描述生成特征子集、评价准则两个过程;根据特征选择和学习算法的不同结合方式对特征选择算法分类,并分析各种方法的优缺点;讨论现有特征选择算法存在的问题,提出一些研究难点和研究方向。     

对抗样本生成及攻防技术研究

基于对抗样本的攻击方法是机器学习算法普遍面临的安全挑战之一。以机器学习的安全性问题为出发点,介绍了当前机器学习面临的隐私攻击、完整性攻击等安全问题,归纳了目前常见对抗样本生成方法的发展过程及各自的特点,总结了目前已有的针对对抗样本攻击的防御技术,最后对提高机器学习算法鲁棒性的方法作了进一步的展望。     

Comparing extended classifier system and genetic programming for financial forecasting: an empirical study

As a broad subfield of artificial intelligence, machine learning is concerned with the development of algorithms and techniques that allow computers to learn. These methods such as fuzzy logic, neural networks, support vector machines, decision trees and Bayesian learning have been applied to learn meaningful rules; however, the only drawback of these methods is that it often gets trapped into a local optimal. In contrast with machine learning methods, a genetic algorithm (GA) is guaranteeing for acquiring better results based on its natural evolution and global searching. GA has given rise to two new fields of research where global optimization is of crucial importance: genetic based machine learning (GBML) and genetic programming (GP). This article adopts the GBML technique to provide a three-phase knowledge extraction methodology, which makes continues and instant learning while integrates multiple rule sets into a centralized knowledge base. Moreover, the proposed system and GP are both applied to the theoretical and empirical experiments. Results for both approaches are presented and compared. This paper makes two important contributions: (1) it uses three criteria (accuracy, coverage, and fitness) to apply the knowledge extraction process which is very effective in selecting an optimal set of rules from a large population; (2) the experiments prove that the rule sets derived by the proposed approach are more accurate than GP.     

基于强化学习的温度感知多核任务调度

随着计算机中内核数量的增多,温度感知的多核任务调度算法成为计算机系统中的一个研究热点.近几年机器学习在各个领域展现出巨大的潜力,很多基于机器学习的系统温度管理研究工作应运而生.其中强化学习因其较强的自适应性,被广泛的运用于温度感知的任务调度算法中.然而目前基于强化学习的温度感知任务调度算法系统建模不够准确,很难做到温度、性能和复杂度的较好权衡.因此,本文提出一种新的基于强化学习的多核温度感知调度算法-ReLeTA,在新的算法中提出了更全面的状态建模方式和更加有效的奖励函数,从而帮助系统进一步降低温度.实验部分通过三个不同的真实计算机平台验证所提方法,实验结果表明了本文所提出方法的有效性以及可扩展性,相比现有方法ReLeTA可以更好的控制系统温度.     

An extensive evaluation of seven machine learning methods for rainfall prediction in weather derivatives

Regression problems provide some of the most challenging research opportunities in the area of machine learning, and more broadly intelligent systems, where the predictions of some target variables are critical to a specific application. Rainfall is a prime example, as it exhibits unique characteristics of high volatility and chaotic patterns that do not exist in other time series data. This work’s main impact is to show the benefit machine learning algorithms, and more broadly intelligent systems have over the current state-of-the-art techniques for rainfall prediction within rainfall derivatives. We apply and compare the predictive performance of the current state-of-the-art (Markov chain extended with rainfall prediction) and six other popular machine learning algorithms, namely: Genetic Programming, Support Vector Regression, Radial Basis Neural Networks, M5 Rules, M5 Model trees, and k-Nearest Neighbours. To assist in the extensive evaluation, we run tests using the rainfall time series across data sets for 42 cities, with very diverse climatic features. This thorough examination shows that the machine learning methods are able to outperform the current state-of-the-art. Another contribution of this work is to detect correlations between different climates and predictive accuracy. Thus, these results show the positive effect that machine learning-based intelligent systems have for predicting rainfall based on predictive accuracy and with minimal correlations existing across climates.     

Applying machine learning techniques for scaling out data quality algorithms in cloud computing environments

Deduplication is the task of identifying the entities in a data set which refer to the same real world object. Over the last decades, this problem has been largely investigated and many techniques have been proposed to improve the efficiency and effectiveness of the deduplication algorithms. As data sets become larger, such algorithms may generate critical bottlenecks regarding memory usage and execution time. In this context, cloud computing environments have been used for scaling out data quality algorithms. In this paper, we investigate the efficacy of different machine learning techniques for scaling out virtual clusters for the execution of deduplication algorithms under predefined time restrictions. We also propose specific heuristics (Best Performing Allocation, Probabilistic Best Performing Allocation, Tunable Allocation, Adaptive Allocation and Sliced Training Data) which, together with the machine learning techniques, are able to tune the virtual cluster estimations as demands fluctuate over time. The experiments we have carried out using multiple scale data sets have provided many insights regarding the adequacy of the considered machine learning algorithms and proposed heuristics for tackling cloud computing provisioning.     

Random walk-based fuzzy linear discriminant analysis for dimensionality reduction

Dealing with high-dimensional data has always been a major problem with the research of pattern recognition and machine learning, and linear discriminant analysis (LDA) is one of the most popular methods for dimensionality reduction. However, it suffers from the problem of being too sensitive to outliers. Hence to solve this problem, fuzzy membership can be introduced to enhance the performance of algorithms by reducing the effects of outliers. In this paper, we analyze the existing fuzzy strategies and propose a new effective one based on Markov random walks. The new fuzzy strategy can maintain high consistency of local and global discriminative information and preserve statistical properties of dataset. In addition, based on the proposed fuzzy strategy, we then derive an efficient fuzzy LDA algorithm by incorporating the fuzzy membership into learning. Theoretical analysis and extensive simulations show the effectiveness of our algorithm. The presented results demonstrate that our proposed algorithm can achieve significantly improved results compared with other existing algorithms.     

网络入侵检测技术综述

随着互联网时代的发展,内部威胁、零日漏洞和DoS攻击等攻击行为日益增加,网络安全变得越来越重要,入侵检测已成为网络攻击检测的一种重要手段。随着机器学习算法的发展,研究人员提出了大量的入侵检测技术。本文对这些研究进行了综述。首先,简要介绍了当前的网络安全形势,并给出了入侵检测技术及系统在各个领域的应用。然后,从数据来源、检测技术和检测性能三个方面对入侵检测相关技术和系统进行已有研究工作的总结与评价,其中,检测技术重点论述了传统机器学习、深度学习、强化学习、可视化分析技术等方法。最后,讨论了当前研究中出现的问题并展望该技术的未来发展方向和前景。本文希望能为该领域的研究人员提供一些有益的思考。     

The journey of graph kernels through two decades

In the real world all events are connected. There is a hidden network of dependencies that governs behavior of natural processes. Without much argument it can be said that, of all the known data-structures, graphs are naturally suitable to model such information. But to learn to use graph data structure is a tedious job as most operations on graphs are computationally expensive, so exploring fast machine learning techniques for graph data has been an active area of research and a family of algorithms called kernel based approaches has been famous among researchers of the machine learning domain. With the help of support vector machines, kernel based methods work very well for learning with Gaussian processes. In this survey we will explore various kernels that operate on graph representations. Starting from the basics of kernel based learning we will travel through the history of graph kernels from its first appearance to discussion of current state of the art techniques in practice.     

Machine Learning for Cataract Classification/Grading on Ophthalmic Imaging Modalities: A Survey

Cataracts are the leading cause of visual impairment and blindness globally. Over the years, researchers have achieved significant progress in developing state-of-the-art machine learning techniques for automatic cataract classification and grading, aiming to prevent cataracts early and improve clinicians’ diagnosis efficiency. This survey provides a comprehensive survey of recent advances in machine learning techniques for cataract classification/grading based on ophthalmic images. We summarize existing literature from two research directions: conventional machine learning methods and deep learning methods. This survey also provides insights into existing works of both merits and limitations. In addition, we discuss several challenges of automatic cataract classification/grading based on machine learning techniques and present possible solutions to these challenges for future research.

     

深度学习典型目标检测算法的改进综述

目标检测是机器视觉领域内最具挑战性的任务之一,深度学习则是目标检测最主流的实现方法.近年来,深度学习理论及技术的快速发展,使得基于深度学习的目标检测算法取得了巨大进展,学者从数据处理、网络结构、损失函数等多方面入手,提出了一系列对于目标检测算法的改进方式.针对典型目标检测算法的改进方式进行综述.归纳了常用数据集和性能评...     

从心理学数据中发现可理解的模式

近年来,机器学习技术常被用于分析心理学数据,以期从数据中找出有价值的模式,更好地刻画和调整人们的心理行为。提出采用二次学习风范的规则生成算法,结合规则学习算法的在模式理解性方面的优势和集成学习、支持向量机等高性能算法在泛化性能上的优势,从心理学数据中发现准确且易于理解的模式。实验表明,采用二次学习风范的规则生成算法在泛化性能上显著高于传统的规则生成算法,且在许多情况下,其输出规则的可理解性亦优于传统的规则生成算法。     

小样本困境下的深度学习图像识别综述

图像识别是图像研究领域的核心问题,解决图像识别问题对人脸识别、自动驾驶、机器人等各领域研究都有重要意义.目前广泛使用的基于深度神经网络的机器学习方法,已经在鸟类分类、人脸识别、日常物品分类等图像识别数据集上达到了超过人类的水平,同时越来越多的工业界应用开始考虑基于深度神经网络的方法,以完成一系列图像识别业务.但是深度学...     

机器学习算法在中医诊疗中的研究综述

机器学习算法包括传统机器学习算法和深度学习算法。传统机器学习算法在中医诊疗领域中的应用研究较多,为探究中医辩证规律提供了参考,也为中医诊疗过程的客观化提供了依据。与此同时,随着其在多个领域不断取得成功,深度学习算法在中医诊疗中的价值越来越多地得到业界的重视。通过对中医诊疗领域中使用到的传统机器学习算法与深度学习算法进行述评,总结了两类算法在中医领域中的研究与应用现状,分析了两类算法的特点以及对中医的应用价值,以期为机器学习算法在中医诊疗领域的进一步研究提供参考。     

Social big data: Recent achievements and new challenges

Big data has become an important issue for a large number of research areas such as data mining, machine learning, computational intelligence, information fusion, the semantic Web, and social networks. The rise of different big data frameworks such as Apache Hadoop and, more recently, Spark, for massive data processing based on the MapReduce paradigm has allowed for the efficient utilisation of data mining methods and machine learning algorithms in different domains. A number of libraries such as Mahout and SparkMLib have been designed to develop new efficient applications based on machine learning algorithms. The combination of big data technologies and traditional machine learning algorithms has generated new and interesting challenges in other areas as social media and social networks. These new challenges are focused mainly on problems such as data processing, data storage, data representation, and how data can be used for pattern mining, analysing user behaviours, and visualizing and tracking data, among others. In this paper, we present a revision of the new methodologies that is designed to allow for efficient data mining and information fusion from social media and of the new applications and frameworks that are currently appearing under the “umbrella” of the social networks, social media and big data paradigms.