Leaf Bagging: A novel meta heuristic optimization based framework for leaf identification

Automated plant recognition based on leaf images is a challenging task among the researchers from several fields. This task requires distinguishing features derived from leaf images for assigning class label to a leaf image. There are several methods in literature for extracting such distinguishing features. In this paper, we propose a novel automated framework for leaf identification. The proposed framework works in multiple phases i.e. pre-processing, feature extraction, classification using bagging approach. Initially, leaf images are pre-processed using image processing operations such as boundary extraction and cropping. In the feature extraction phase, popular nature inspired optimization algorithms viz. Spider Monkey Optimization (SMO), Particle Swarm Optimization (PSO) and Gray Wolf Optimization (GWO) have been exploited for reducing the dimensionality of features. In the last phase, a leaf image is classified by multiple classifiers and then output of these classifiers is combined using majority voting. The effectiveness of the proposed framework is established based on the experimental results obtained on three datasets i.e. Flavia, Swedish and self-collected leaf images. On all the datasets, it has been observed that the classification accuracy of the proposed method is better than the individual classifiers. Furthermore, the classification accuracy for the proposed approach is comparable to deep learning based method on the Flavia dataset.

     

Hybrid deep learning model for answering visual medical questions

Due to the increase in electronic documents containing medical information, the search for specific information is often complex and time-consuming. This has prompted the development of new tools designed to address this issue. Automated visual question/answer (VQA) systems are becoming more challenging to develop. These are computer programs that take images and questions as input and then combine all inputs to generate text-based answers. Due to the enormous amount of question and the limited number of specialists, many issues stay unanswered. It’s possible to solve this problem by using automatic question classifiers that guide queries to experts based on their subject preferences. For these purposes, we propose a VQA approach based on a hybrid deep learning model. The model consists of three steps: (1) the classification of medical questions based on a BERT model; (2) image and text feature extraction using a deep learning model, more specifically the extraction of medical image features by a hybrid deep learning model; and (3) text feature extraction using a Bi-LSTM model. Finally, to predict the appropriate answer, our approach uses a KNN model. Additionally, this study examines the influence of the Adam, AdaGrad, Stochastic gradient descent and RMS Prop optimization techniques on the performance of the network. As a consequence of the studies, it was shown that Adam and SGD optimization algorithms consistently produced higher outcomes. Experiments using the ImageCLEF 2019 dataset revealed that the suggested method increases BLEU and WBSS values considerably.

     

基于依存关系的问句理解与问句分类

问句理解是问答系统的首要过程,问句分类是问句理解的主要组成部分,它在问答系统中具有非常重要的作用,因为问句类型有助于在文档中定位和抽取答案。问句分类的目标是基于预期的答案类型,准确地分类问句。本文提出依存关系规则与统计方法相结合,实现了基于依存关系的中文问句理解与问句分类机制。实验表明：支持向量机结合依存关系的特征抽取方法,获得了较高问句分类正确率。     

Bayesian hypothesis testing for pattern discrimination in brain decoding

Research in cognitive neuroscience and in brain–computer interfaces (BCI) is frequently concerned with finding evidence that a given brain area processes, or encodes, given stimuli. Experiments based on neuroimaging techniques consist of a stimulation protocol presented to a subject while his or her brain activity is being recorded. The question is then whether there is enough evidence of brain activity related to the stimuli within the recorded data. Finding a link between brain activity and stimuli has recently been proposed as a classification task, called brain decoding. A classifier that can accurately predict which stimuli were presented to the subject provides support for a positive answer to the question. However, it is only the answer for a given data set and the question still remains whether it is a general rule that will apply also to new data. In this paper we try to reliably answer the neuroscientific question about the presence of a significant link between brain activity and stimuli once we have the classification results. The proposed method is based on a Beta-Binomial model for the population of generalization errors of classifiers from multi-subject studies within the Bayesian hypothesis testing framework. We present an application on nine brain decoding investigations from a real functional magnetic resonance imaging (fMRI) experiment about the relation between mental calculation and eye movements.     

Unsupervised feature selection with graph learning via low-rank constraint

Feature selection is one of the most important machine learning procedure, and it has been successfully applied to make a preprocessing before using classification and clustering methods. High-dimensional features often appear in big data, and it’s characters block data processing. So spectral feature selection algorithms have been increasing attention by researchers. However, most feature selection methods, they consider these tasks as two steps, learn similarity matrix from original feature space (may be include redundancy for all features), and then conduct data clustering. Due to these limitations, they do not get good performance on classification and clustering tasks in big data processing applications. To address this problem, we propose an Unsupervised Feature Selection method with graph learning framework, which can reduce the redundancy features influence and utilize a low-rank constraint on the weight matrix simultaneously. More importantly, we design a new objective function to handle this problem. We evaluate our approach by six benchmark datasets. And all empirical classification results show that our new approach outperforms state-of-the-art feature selection approaches.     

基于知网的中文问题自动分类

问答系统应能用准确、简洁的答案回答用户用自然语言提出的问题。问题分类是问答系统所要处理的第一步,分类结果的正确率直接影响后续工作的进行。本文提出了一种使用知网作为语义资源选取分类特征,并使用最大熵模型进行分类的新方法。该方法以问题的疑问词、句法结构、疑问意向词、疑问意向词在知网中的首义原作为分类特征。实验结果表明,在知网中选取的首义原能很好的表达问题焦点词的语义信息,可作为问题分类的一个主要特征。该方法能显著地提高问题分类的精度,大类和小类的分类精度分别达到了92.18%和83.86%。     

Computationally efficient scoring of activity using demographics and connectivity of entities

Consider a collection of entities, where each may have some demographic properties, and where the entities may be linked in some kind of, perhaps social, network structure. Some of these entities are “of interest”—we call them active. What is the relative likelihood of each of the other entities being active? AFDL, Activity from Demographics and Links, is an algorithm designed to answer this question in a computationally-efficient manner. AFDL is able to work with demographic data, link data (including noisy links), or both; and it is able to process very large datasets quickly. This paper describes AFDL’s feature extraction and classification algorithms, gives timing and accuracy results obtained for several datasets, and offers suggestions for its use in real-world situations.     

图像灰度密度分布计算模型及肺结节良恶性分类

提出一种基于密度分布的特征评估算法,同时引入模式识别模型来评估该方法的效率。首先,从肺部肿瘤图像中随机提取像素块集,通过K-均值聚类算法将其分为10类,根据CT图像中肺结节像素值和聚类中心的关系,提取出10维特征向量,利用随机森林分类器进行模型训练,进而判断肺结节良恶性水平。通过CT图像公开数据集LIDC-IDRI实验表明分类平均精度达到0.900 8。实验结果对比分析表明,提出的特征表达方法具有更优的分类效果和更高的鲁棒性。     

CEVCLUS: evidential clustering with instance-level constraints for relational data

Recent advances in clustering consider incorporating background knowledge in the partitioning algorithm, using, e.g., pairwise constraints between objects. As a matter of fact, prior information, when available, often makes it possible to better retrieve meaningful clusters in data. Here, this approach is investigated in the framework of belief functions, which allows us to handle the imprecision and the uncertainty of the clustering process. In this context, the EVCLUS algorithm was proposed for partitioning objects described by a dissimilarity matrix. It is extended here so as to take pairwise constraints into account, by adding a term to its objective function. This term corresponds to a penalty term that expresses pairwise constraints in the belief function framework. Various synthetic and real datasets are considered to demonstrate the interest of the proposed method, called CEVCLUS, and two applications are presented. The performances of CEVCLUS are also compared to those of other constrained clustering algorithms.     

Unsupervised feature selection based on kernel fisher discriminant analysis and regression learning

In this paper, we propose a new feature selection method called kernel fisher discriminant analysis and regression learning based algorithm for unsupervised feature selection. The existing feature selection methods are based on either manifold learning or discriminative techniques, each of which has some shortcomings. Although some studies show the advantages of two-steps method benefiting from both manifold learning and discriminative techniques, a joint formulation has been shown to be more efficient. To do so, we construct a global discriminant objective term of a clustering framework based on the kernel method. We add another term of regression learning into the objective function, which can impose the optimization to select a low-dimensional representation of the original dataset. We use L_2,1-norm of the features to impose a sparse structure upon features, which can result in more discriminative features. We propose an algorithm to solve the optimization problem introduced in this paper. We further discuss convergence, parameter sensitivity, computational complexity, as well as the clustering and classification accuracy of the proposed algorithm. In order to demonstrate the effectiveness of the proposed algorithm, we perform a set of experiments with different available datasets. The results obtained by the proposed algorithm are compared against the state-of-the-art algorithms. These results show that our method outperforms the existing state-of-the-art methods in many cases on different datasets, but the improved performance comes with the cost of increased time complexity.

     

A framework for cost-based feature selection

Over the last few years, the dimensionality of datasets involved in data mining applications has increased dramatically. In this situation, feature selection becomes indispensable as it allows for dimensionality reduction and relevance detection. The research proposed in this paper broadens the scope of feature selection by taking into consideration not only the relevance of the features but also their associated costs. A new general framework is proposed, which consists of adding a new term to the evaluation function of a filter feature selection method so that the cost is taken into account. Although the proposed methodology could be applied to any feature selection filter, in this paper the approach is applied to two representative filter methods: Correlation-based Feature Selection (CFS) and Minimal-Redundancy-Maximal-Relevance (mRMR), as an example of use. The behavior of the proposed framework is tested on 17 heterogeneous classification datasets, employing a Support Vector Machine (SVM) as a classifier. The results of the experimental study show that the approach is sound and that it allows the user to reduce the cost without compromising the classification error.     

Subspace learning for unsupervised feature selection via matrix factorization

Dimensionality reduction is an important and challenging task in machine learning and data mining. Feature selection and feature extraction are two commonly used techniques for decreasing dimensionality of the data and increasing efficiency of learning algorithms. Specifically, feature selection realized in the absence of class labels, namely unsupervised feature selection, is challenging and interesting. In this paper, we propose a new unsupervised feature selection criterion developed from the viewpoint of subspace learning, which is treated as a matrix factorization problem. The advantages of this work are four-fold. First, dwelling on the technique of matrix factorization, a unified framework is established for feature selection, feature extraction and clustering. Second, an iterative update algorithm is provided via matrix factorization, which is an efficient technique to deal with high-dimensional data. Third, an effective method for feature selection with numeric data is put forward, instead of drawing support from the discretization process. Fourth, this new criterion provides a sound foundation for embedding kernel tricks into feature selection. With this regard, an algorithm based on kernel methods is also proposed. The algorithms are compared with four state-of-the-art feature selection methods using six publicly available datasets. Experimental results demonstrate that in terms of clustering results, the proposed two algorithms come with better performance than the others for almost all datasets we experimented with here.     

IntensityPatches and RegionPatches for image recognition

In this paper, we propose a framework for defining feature extraction techniques, called Pixel Clustering. It is an extension of feature extraction with Wavelets. We propose two linear feature extraction techniques using Pixel Clustering: IntensityPatches and RegionPatches. We assess the methods in color and grayscale image datasets: two face datasets and two object datasets. The proposed methods present a short computation time for feature extraction and high accuracy compared with linear feature extraction methods and other state-of-the-art feature extraction techniques.     

一种用于处理高维稀疏数据的半监督聚类算法

半监督聚类是近年来研究的热点,传统的方法是在无监督算法的基础上加入有限的背景知识来提高聚类性能.然而大多数半监督聚类技术都基于邻近或密度,难以处理高维数据,因此必须将约减的特征加入到半监督聚类过程中.为解决此问题,提出了一种新的半监督聚类算法框架.该算法利用样本约束传递性进行预处理,然后将特征投影到低维空间实现降维,最终用半监督算法对约减后的样本进行聚类.通过实验同现行主要降维方法进行了比较,说明此方法能有效地处理高维数据,聚类效果良好.     

问题分类的计算模型研究

问题分类是问答系统技术处理的基础与核心，它决定答案抽取的范围和方法，进而影响整个系统的性能。本文提出了一个基于贝叶斯理论的问题分类计算模型，并给出其详细算法。研究分析了问句内部结构与问题类型之间的关系，将基于疑问词的2-gram组合和问句特征项同义近义扩展应用到具体计算中。实验表明，效果较为理想。     

Generalized re-weighting local sampling mean discriminant analysis

Despite the general success in the pattern recognition community, linear discriminant analysis (LDA) has four intrinsic drawbacks. In this paper, we propose a new feature extraction algorithm, namely, local sampling mean discriminant analysis (LSMDA), to make up for the first three drawbacks, and a generalized re-weighting (GRW) framework to make up for the fourth drawback. Extensive experiments are conducted on both synthetic and real-world datasets to evaluate the classification performance of our work. The experimental results demonstrate the effectiveness of both LSMDA and the GRW framework in classifications.     

基于句法结构特征分析及分类技术的答案提取算法

由于中文自然语言处理的特点和困难以及相应的语言处理基础资源的相对缺乏,使得国外一些成熟技术和研究成果不能直接应用到中文问答系统中.为此,针对中文事实型问答系统,提出一种新的基于句法结构特征分析及分类技术的答案提取算法,该方法将答案提取问题看成是候选答案的分类问题,即将候选答案分类为正确和错误两类.首先,该方法根据与问题类型所对应的候选答案的类型信息,从文本片断中提取出候选答案及其在句子中的简单特征和句法结构特征;然后利用这些特征训练分类器;最后用训练得到的分类器判别候选答案是否为正确答案.针对中文事实性问题,该方法与目前典型的基于模式匹配的中文答案提取算法相比,准确率提升6.2%,MRR提升9.7%.     

A survey: facial micro-expression recognition

Facial expression recognition plays a crucial role in a wide range of applications of psychotherapy, security systems, marketing, commerce and much more. Detecting a macro-expression, which is a direct representation of an ‘emotion,’ is a relatively straight-forward task. Playing a pivotal role as macro-expressions, micro-expressions are more accurate indicators of a train of thought or even subtle, passive or involuntary thoughts. Compared to macro-expressions, identifying micro-expressions is a much more challenging research question because their time spans are narrowed down to a fraction of a second, and can only be defined using a broader classification scale. This paper is an all-inclusive survey-cum-analysis of the various micro-expression recognition techniques. We analyze the general framework for micro-expression recognition system by decomposing the pipeline into fundamental components, namely face detecting, pre-processing, facial feature detection and extraction, datasets, and classification. We discuss the role of these elements and highlight the models and new trends that are followed in their design. Moreover, we provide an extensive analysis of micro-expression recognition systems by comparing their performance. We also discuss the new deep learning features that can, in the near future, replace the hand-crafted features for facial micro-expression recognition. This survey has been developed, focusing on the methodologies applied, databases used, performance regarding recognition accuracy and comparing these to distil the gaps in the efficiencies, future scope, and research potentials. Through this survey, we intend to look into this problem and develop a comprehensive and efficient recognition scheme. This study allows us to identify open issues and to determine future directions for designing real-world micro-expression recognition systems.     

基于深度神经网络的图像碎片化信息问答算法

大量结构无序、内容片面的碎片化信息以文本、图像、视频、网页等不同模态的形式,高度分散存储在不同数据源中,现有的研究通过构建视觉问答系统(visual question answering, VQA),实现对多模态碎片化信息的提取、表达和理解.视觉问答任务给定与图像相关的一个问题,推理相应的答案.在视觉问答任务的基本背景下,以设计出完备的图像碎片化信息问答的框架与算法为目标,重点研究包括图像特征提取、问题文本特征提取、多模态特征融合和答案推理的模型与算法.构建深度神经网络模型提取用于表示图像与问题信息的特征,结合注意力机制与变分推断方法关联图像与问题2种模态特征并推理答案.实验结果表明：该模型能够有效提取和理解多模态碎片化信息,并提高视觉问答任务的准确率.