nils-herrmann/clean_scirepeval huggingface dataset:
Graph Embedding Exploiting Subclasses

Recently, subspace learning methods for Dimensionality Reduction (DR), like Subclass Discriminant Analysis (SDA) and Clustering-based Discriminant Analysis (CDA), which use subclass information for the discrimination between the data classes, have attracted much attention. In parallel, important work has been accomplished on Graph Embedding (GE), which is a general framework unifying several subspace learning techniques. In this paper, GE has been extended in order to integrate subclass discriminant information resulting to the novel Subclass Graph Embedding (SGE) framework. The kernelization of SGE is also presented. It is shown that SGE comprises a generalization of the typical GE including subclass DR methods. In this context, the theoretical link of SDA and CDA methods with SGE is established. The efficacy and power of SGE has been substantiated by comparing subclass DR methods versus a diversity of unimodal methods all pertaining to the SGE framework via a series of experiments on various real-world data.
Exploiting symmetry in two-dimensional clustering-based discriminant analysis for face recognition

Subspace learning techniques are among the most popular methods for face recognition. In this paper, we propose a novel face recognition technique for two dimensional subspace learning which is able to exploit the symmetry nature of human faces. We extent the Two Dimensional Clustering based Discriminant Analysis (2DCDA) by incorporating an appropriate symmetry regularizer into its objective function in order to determine symmetric projection vectors. The proposed Symmetric Two Dimensional Clustering based Discriminant Analysis technique has been applied to the face recognition problem. Experimental results showed that the proposed technique achieves better classification performance in comparison to the standard one.
Recent advances in discriminant non-negative Matrix Factorization

Non-negative Matrix Factorization (NMF) is among the most popular subspace methods widely used in a variety of pattern recognition applications. Recently, a discriminant NMF method that incorporates Linear Discriminant Analysis criteria and achieves an efficient decomposition of the provided data to its salient parts has been proposed. An extension of this work specialized for classification, optimized using projected gradients in order to ensure converge to a stationary limit point, resulted in a more efficient method of the latter approach. Assuming multimodality of the underlying data samples distribution and incorporating clustering discriminant inspired constraints into the NMF decomposition cost function, resulted in the Subclass Discriminant NMF algorithm which found to outperform both approaches under real life settings. In this work we review all these methods in the context of various pattern recognition problems using facial images.
Blind robust watermarking schemes for copyright protection of 3D mesh objects

In this paper, two novel methods suitable for blind 3D mesh object watermarking applications are proposed. The first method is robust against 3D rotation, translation, and uniform scaling. The second one is robust against both geometric and mesh simplification attacks. A pseudorandom watermarking signal is cast in the 3D mesh object by deforming its vertices geometrically, without altering the vertex topology. Prior to watermark embedding and detection, the object is rotated and translated so that its center of mass and its principal component coincide with the origin and the z-axis of the Cartesian coordinate system. This geometrical transformation ensures watermark robustness to translation and rotation. Robustness to uniform scaling is achieved by restricting the vertex deformations to occur only along the r coordinate of the corresponding (r, /spl theta/, /spl phi/) spherical coordinate system. In the first method, a set of vertices that correspond to specific angles /spl theta/ is used for watermark embedding. In the second method, the samples of the watermark sequence are embedded in a set of vertices that correspond to a range of angles in the /spl theta/ domain in order to achieve robustness against mesh simplifications. Experimental results indicate the ability of the proposed method to deal with the aforementioned attacks.
Representative Class Vector Clustering-Based Discriminant Analysis

Clustering-based Discriminant Analysis (CDA) is a well-known technique for supervised feature extraction and dimensionality reduction. CDA determines an optimal discriminant subspace for linear data projection based on the assumptions of normal subclass distributions and subclass representation by using the mean subclass vector. However, in several cases, there might be other subclass representative vectors that could be more discriminative, compared to the mean subclass vectors. In this paper we propose an optimization scheme aiming at determining the optimal subclass representation for CDA-based data projection. The proposed optimization scheme has been evaluated on standard classification problems, as well as on two publicly available human action recognition databases providing enhanced class discrimination, compared to the standard CDA approach.
Multimodal Stereoscopic Movie Summarization Conforming to Narrative Characteristics

Video summarization is a timely and rapidly developing research field with broad commercial interest, due to the increasing availability of massive video data. Relevant algorithms face the challenge of needing to achieve a careful balance between summary compactness, enjoyability, and content coverage. The specific case of stereoscopic 3D theatrical films has become more important over the past years, but not received corresponding research attention. In this paper, a multi-stage, multimodal summarization process for such stereoscopic movies is proposed, that is able to extract a short, representative video skim conforming to narrative characteristics from a 3D film. At the initial stage, a novel, low-level video frame description method is introduced (frame moments descriptor) that compactly captures informative image statistics from luminance, color, optical flow, and stereoscopic disparity video data, both in a global and in a local scale. Thus, scene texture, illumination, motion, and geometry properties may succinctly be contained within a single frame feature descriptor, which can subsequently be employed as a building block in any key-frame extraction scheme, e.g., for intra-shot frame clustering. The computed key-frames are then used to construct a movie summary in the form of a video skim, which is post-processed in a manner that also considers the audio modality. The next stage of the proposed summarization pipeline essentially performs shot pruning, controlled by a user-provided shot retention parameter, that removes segments from the skim based on the narrative prominence of movie characters in both the visual and the audio modalities. This novel process (multimodal shot pruning) is algebraically modeled as a multimodal matrix column subset selection problem, which is solved using an evolutionary computing approach. Subsequently, disorienting editing effects induced by summarization are dealt with, through manipulation of the video skim. At the last step, the skim is suitably post-processed in order to reduce stereoscopic video defects that may cause visual fatigue.
Neural representation and learning for multi-view human action recognition

In this paper we propose a novel method aiming at view-independent multi-view action recognition. Instead of combining the information provided by all the cameras forming the camera setup, for action representation and classification, we perform single-view action representation and classification to all the available videos depicting the person under consideration independently. Action representation involves a self organizing neural network training followed by fuzzy vector quantization. Action classification is performed by a feedforward neural network which is trained for view-invariant action recognition. Multiple action classification results combination based on Bayesian learning, in the recognition phase, results to high action recognition accuracy. The performance of the proposed action recognition method is evaluated on two publicly available databases, aiming at different application scenarios.
Exploiting graph embedding in support vector machines

In this paper we introduce a novel classification framework that is based on the combination of the support vector machine classifier and the graph embedding framework. In particular we propose the substitution of the support vector machine kernel with sub-space or sub-manifold kernels, that are constructed based on the graph embedding framework. Our technique combines the very good generalization ability of the support vector machine classifier with the flexibility of the graph embedding framework resulting in improved classification performance. The attained experimental results on several benchmark and real-life data sets, further support our claim of improved classification performance.
Multi-modal label propagation based on a higher order similarity matrix

A novel method is introduced for label propagation on similarity tensors. The proposed method operates on data with multiple representations. A higher order similarity matrix is constructed for describing the relationship between the data representations in different modalities. Then, label propagation is performed on the above mentioned similarity matrix, by extending the state of the art label propagation method with local and global consistency to the case of higher order similarity graphs. The evaluation of the proposed method was performed on two classification tasks: person recognition on facial images extracted from three stereo movies and human action recognition on two data sets consisting of videos downloaded from YouTube. Experimental results showed that the proposed label propagation approach achieves either competitive or better classification accuracy from the state of the art in all classification tasks.
Pairwise facial expression classification

This paper presents a novel facial expression recognition methodology. In order to classify the expression of a test face to one of seven pre-determined facial expression classes, multiple two-class classification tasks are carried out. For each such task, a unique set of features is identified that is enhanced, in terms of its ability to help produce a proper separation between the two specific classes. The selection of these sets of features is accomplished by making use of a class separability measure that is utilized in an iterative process. Fisher's linear discriminant is employed in order to produce the separation between each pair of classes and train each two-class classifier. In order to combine the classification results from all two-class classifiers, the ‘voting’ classifier-decision fusion process is employed. The standard JAFFE database is utilized in order to evaluate the performance of this algorithm. Experimental results show that the proposed methodology provides a good solution to the facial expression recognition problem.
Big Data Analysis for Media Production

A typical high-end film production generates several terabytes of data per day, either as footage from multiple cameras or as background information regarding the set (laser scans, spherical captures, etc). This paper presents solutions to improve the integration of the multiple data sources, and understand their quality and content, which are useful both to support creative decisions on-set (or near it) and enhance the postproduction process. The main cinema specific contributions, tested on a multisource production dataset made publicly available for research purposes, are the monitoring and quality assurance of multicamera set-ups, multisource registration and acceleration of 3-D reconstruction, anthropocentric visual analysis techniques for semantic content annotation, and integrated 2-D-3-D web visualization tools. We discuss as well improvements carried out in basic techniques for acceleration, clustering and visualization, which were necessary to deal with the very large multisource data, and can be applied to other big data problems in diverse application fields.
Robust spatial image watermarking using progressive detection

A novel method for image watermarking robust to geometric distortions is proposed. A binary watermark is embedded in a grayscale or a color host image. The ability of progressive watermark detection enables fast and robust watermark detection even after several geometric distortions of the watermarked image. Simulation results indicate the ability of the proposed method to deal with the aforementioned attacks. Experiments conducted using the Stirmark benchmarking tests, indicate the superiority of the proposed method.
Using deep learning to detect price change indications in financial markets

Forecasting financial time-series has long been among the most challenging problems in financial market analysis. In order to recognize the correct circumstances to enter or exit the markets investors usually employ statistical models (or even simple qualitative methods). However, the inherently noisy and stochastic nature of markets severely limits the forecasting accuracy of the used models. The introduction of electronic trading and the availability of large amounts of data allow for developing novel machine learning techniques that address some of the difficulties faced by the aforementioned methods. In this work we propose a deep learning methodology, based on recurrent neural networks, that can be used for predicting future price movements from large-scale high-frequency time-series data on Limit Order Books. The proposed method is evaluated using a large-scale dataset of limit order book events.
Stereo facial image clustering using double spectral analysis

In this work we proposed a new variant of spectral clustering using double spectral analysis which proved to be able to achieve better clustering results. The present work focuses on the special case of 3D videos and the implication of their use. Various improvements are introduced including the use of stereo over mono videos, the use of double spectral clustering over spectral clustering and the use of multiple representative images per trajectory for more robust trajectory representation. Extended experiments have been conducted in three 3D full feature commercial films which revealed the power of stereo face clustering in comparison with single channel face clustering.
Visual Voice Activity Detection in the Wild

The visual voice activity detection (V-VAD) problem in unconstrained environments is investigated in this paper. A novel method for V-VAD in the wild, exploiting local shape and motion information appearing at spatiotemporal locations of interest for facial video segment description and the bag of words model for facial video segment representation, is proposed. Facial video segment classification is subsequently performed using the state-of-the-art classification algorithms. Experimental results on one publicly available V-VAD dataset denote the effectiveness of the proposed method, since it achieves better generalization performance in unseen users, when compared to the recently proposed state-of-the-art methods. Additional results on a new unconstrained dataset provide evidence that the proposed method can be effective even in such cases in which any other existing method fails.
Exploiting subclass information in one-class support vector machine for video summarization

In this paper, we propose a method for video summarization based on human activity description. We formulate this problem as the one of automatic video segment selection based on a learning process that employs salient video segment paradigms. For this one-class classification problem, we introduce a novel variant of the One-Class Support Vector Machine (OC-SVM) classifier that exploits subclass information in the OC-SVM optimization problem, in order to jointly minimize the data dispersion within each subclass and determine the optimal decision function. We evaluate the proposed approach in three Hollywood movies, where the performance of the proposed SOC-SVM algorithm is compared with that of the OC-SVM. Experimental results denote that the proposed approach is able to outperform OC-SVM-based video segment selection.
Learning Neural Bag-of-Features for Large-Scale Image Retrieval

In this paper, the well-known bag-of-features (BoFs) model is generalized and formulated as a neural network that is composed of three layers: 1) a radial basis function (RBF) layer; 2) an accumulation layer; and 3) a fully connected layer. This formulation allows for decoupling the representation size from the number of used codewords, as well as for better modeling the feature distribution using a separate trainable scaling parameter for each RBF neuron. The resulting network, called retrieval-oriented neural BoF (RN-BoF), is trained using regular back propagation and allows for fast extraction of compact image representations. It is demonstrated that the RN-BoF model is capable of: 1) increasing the object encoding and retrieval speed; 2) reducing the extracted representation size; and 3) increasing the retrieval precision. A symmetry-aware spatial segmentation technique is also proposed to further reduce the encoding time and the storage requirements and allows the method to efficiently scale to large datasets. The proposed method is evaluated and compared to other state-of-the-art techniques using five different image datasets, including the large-scale YouTube Faces database.
Exploiting discriminant information in elastic graph matching

In this paper, we investigate the use of discriminant techniques in the elastic graph matching (EGM) algorithm. First we use discriminant analysis in the feature vectors of the nodes in order to find the most discriminant features. The similarity measure for discriminant feature vectors and the node deformation are combined in a discriminant manner in order to form a local similarity measure between nodes. Moreover, the local similarity values at the nodes of the elastic graph, are weighted by coefficients that are also derived by some discriminant analysis in order to form a total similarity measure between faces. We illustrate the improvements in performance in frontal face verification using a modified multiscale morphological analysis.
View-independent human action recognition based on multi-view action images and discriminant learning

In this paper a novel view-independent human action recognition method is proposed. A multi-camera setup is used to capture the human body from different viewing angles. Actions are described by a novel action representation, the so-called multi-view action image (MVAI), which effectively addresses the camera viewpoint identification problem, i.e., the identification of the position of each camera with respect to the person's body. Linear Discriminant Analysis is applied on the MVAIs in order to to map actions to a discriminant feature space where actions are classified by using a simple nearest class centroid classification scheme. Experimental results denote the effectiveness of the proposed action recognition approach.
Learning Discriminant Person-Specific Facial Models Using Expandable Graphs

In this paper, a novel algorithm for finding discriminant person-specific facial models is proposed and tested for frontal face verification. The most discriminant features of a person's face are found and a deformable model is placed in the spatial coordinates that correspond to these discriminant features. The discriminant deformable models, for verifying the person's identity, that are learned through this procedure are elastic graphs that are dense in the facial areas considered discriminant for a specific person and sparse in other less significant facial areas. The discriminant graphs are enhanced by a discriminant feature selection method for the graph nodes in order to find the most discriminant jet features. The proposed approach significantly enhances the performance of elastic graph matching in frontal face verification
A blind robust watermarking scheme for copyright protection of 3D mesh models

In this paper, a novel method for blind 3D mesh model watermarking applications is proposed. The method is robust against 3D translation, scaling and mesh simplifications. A pseudo-random watermarking signal is casted in the 3D mesh model by geometrically deforming its vertices, without altering the vertex topology. Prior to embedding and detection, a set of simple transforms is applied to the 3D mesh model. Each sample of the watermark sequence is embedded in a set of vertices rather than in a single vertex in order to deal with mesh simplifications. Experimental results indicate the ability of the proposed method to deal with the aforementioned attacks.
Visual object tracking based on the object's salient features with application in automatic nutrition assistance

A novel method for object tracking in videos which can find application in eating and drinking activity recognition is proposed. The query object is detected in the first video frame, extracting a new query image. The initial query image along with the obtained query image are then compared with patches within a determined search region around the position of the detected object in the previous frame. For each image, the local steering kernels are extracted and the similarity between a query image and the patches of the video frame is measured by calculating the cosine similarity. The proposed method finds application in eating and drinking activity recognition.
Multidimensional Sequence Classification Based on Fuzzy Distances and Discriminant Analysis

In this paper, we present a novel method aiming at multidimensional sequence classification. We propose a novel sequence representation, based on its fuzzy distances from optimal representative signal instances, called statemes. We also propose a novel modified clustering discriminant analysis algorithm minimizing the adopted criterion with respect to both the data projection matrix and the class representation, leading to the optimal discriminant sequence class representation in a low-dimensional space, respectively. Based on this representation, simple classification algorithms, such as the nearest subclass centroid, provide high classification accuracy. A three step iterative optimization procedure for choosing statemes, optimal discriminant subspace and optimal sequence class representation in the final decision space is proposed. The classification procedure is fast and accurate. The proposed method has been tested on a wide variety of multidimensional sequence classification problems, including handwritten character recognition, time series classification and human activity recognition, providing very satisfactory classification results.