In this article, we report on the creation of a publicly available, common evaluation framework for Violent Scenes Detection (VSD) in Hollywood and YouTube videos. We propose a robust data set, the VSD96, with more than 96 hours of video of various genres, annotations at different levels of detail (e.g., shot-level, segment-level), annotations of mid-level concepts (e.g., blood, fire), various pre-computed multi-modal descriptors, and over 230 system output results as baselines. This is the most comprehensive data set available to this date tailored to the VSD task and was extensively validated during the MediaEval benchmarking campaigns. Furthermore, we provide an in-depth analysis of the crucial components of VSD algorithms, by reviewing the capabilities and the evolution of existing systems (e.g., overall trends and outliers, the influence of the employed features and fusion techniques, the influence of deep learning approaches). Finally, we discuss the possibility of going beyond state-of-the-art performance via an ad-hoc late fusion approach. Experimentation is carried out on the VSD96 data. We provide the most important lessons learned and gained insights. The increasing number of publications using the VSD96 data underline the importance of the topic. The presented and published resources are a practitioner's guide and also a strong baseline to overcome, which will help researchers for the coming years in analyzing aspects of audio-visual affect and violence detection in movies and videos.

Everyday digital tasks can highly benefit from systems that recommend the right information to use at the right time. However, existing solutions typically support only specific applications and tasks. In this demo, we showcase EntityBot, a system that captures context across application boundaries and recommends information entities related to the current task. The user’s digital activity is continuously monitored by capturing all content on the computer screen using optical character recognition. This includes all applications and services being used and specific to individuals’ computer usages such as instant messaging, emailing, web browsing, and word processing. A linear model is then applied to detect the user’s task context to retrieve entities such as applications, documents, contact information, and several keywords determining the task. The system has been evaluated with real-world tasks, demonstrating that the recommendation had an impact on the tasks and led to high user satisfaction.

Recommender systems can support everyday digital tasks by retrieving and recommending useful information contextually. This is becoming increasingly relevant in services and operating systems. Previous research often focuses on specific recommendation tasks with data captured from interactions with an individual application. The quality of recommendations is also often evaluated addressing only computational measures of accuracy, without investigating the usefulness of recommendations in realistic tasks. The aim of this work is to synthesize the research in this area through a novel approach by (1) demonstrating comprehensive digital activity monitoring, (2) introducing entity-based computing and interaction, and (3) investigating the previously overlooked usefulness of entity recommendations and their actual impact on user behavior in real tasks. The methodology exploits context from screen frames recorded every 2 seconds to recommend information entities related to the current task. We embodied this methodology in an interactive system and investigated the relevance and influence of the recommended entities in a study with participants resuming their real-world tasks after a 14-day monitoring phase. Results show that the recommendations allowed participants to find more relevant entities than in a control without the system. In addition, the recommended entities were also used in the actual tasks. In the discussion, we reflect on a research agenda for entity recommendation in context, revisiting comprehensive monitoring to include the physical world, considering entities as actionable recommendations, capturing drifting intent and routines, and considering explainability and transparency of recommendations, ethics, and ownership of data.

A significant fraction of information searches are motivated by the user’s primary task . An ideal search engine would be able to use information captured from the primary task to proactively retrieve useful information. Previous work has shown that many information retrieval activities depend on the primary task in which the retrieved information is to be used, but fairly little research has been focusing on methods that automatically learn the informational intents from the primary task context. We study how the implicit primary task context can be used to model the user’s search intent and to proactively retrieve relevant and useful information. Data comprising of logs from a user study, in which users are writing an essay, demonstrate that users’ search intents can be captured from the task and relevant and useful information can be proactively retrieved. Data from simulations with several datasets of different complexity show that the proposed approach of using primary task context generalizes to a variety of data. Our findings have implications for the design of proactive search systems that can infer users’ search intent implicitly by monitoring users’ primary task activities.

The affective content of a movie is often considered to be largely determined by its style and aesthetics. Recently, studies have attempted to estimate affective movie content with computational features, but results have been mixed, one of the main reasons being a lack of data on perceptual stylistic and aesthetic attributes of film, which would provide a ground truth for the features. The distinctions between energetic and tense arousal as well as perceived and felt affect are also often neglected. In this study, we present a data set of ratings by 73 viewers of 83 stylistic, aesthetic, and affective attributes for a selection of movie clips containing complete scenes taken from mainstream movies. The affective attributes include the temporal progression of perceived and felt valence and arousal within the clips. The data set is aimed to be used to train algorithms that predict viewer assessments based on low-level computational features. With this data set, we performed a baseline study modeling the relation between a large selection of low-level computational features (i.e., visual, auditory, and temporal) and perceptual stylistic, aesthetic, and affective attributes of movie clips. Two algorithms were compared in a realistic prediction scenario: linear regression and the neural-network-based Extreme Learning Machine (ELM). Felt and perceived affect as well as stylistic attributes were shown to be equally easy to predict, whereas the prediction of aesthetic attributes failed. The performance of the ELM predictor was overall found to be slightly better than the linear regression. A feature selection experiment illustrated that features from all low-level computational modalities, visual, auditory and temporal, contribute to the prediction of the affect assessments. We have made our assessment data and extracted computational features publicly available.

Many emerging application areas in video and image processing require large-scale visual concept detection. Examples include content-based indexing of online user-generated videos and 24/7 archival of TV broadcasts. The current state of the art in concept detection uses bag-of-visual-words features with computationally heavy exponential kernel classifiers. We argue that this classifier approach is not feasible for large-scale real-time applications, and propose instead to use combinations of approximate additive kernel classifiers. By using explicit kernel maps and the power mean SVM, followed by fusion of classifiers trained on different features, we achieve high retrieval precision while retaining real-time performance for large sets of concepts. This paper presents a series of experiments with the large-scale TRECVID 2012 video database and the commonly used Fifteen Scene Categories image database. We show significantly improved retrieval performance over standard linear classifiers, and by late fusion over several visual features, the approximative additive kernels outperform any single exponential kernel in only a fraction of the detection time.