Catálogo de publicaciones - revistas

<jats:p>Inter-connected cloud computing is an inherent evolution of Cloud Computing. Numerous benefits provided by connecting clouds have garnered attraction from the academic as well as the industry sector. Just as every new evolution faces challenges, inter-connected clouds have their own set of challenges such as security, monitoring, authorization and identity management, vendor lock-in, and so forth. This article considers the vendor lock-in problem, which is a direct consequence of the lack of interoperability and portability. An extensive literature review by surveying more than 120 papers has been done to analyze and categorize various solutions suggested in literature for solving the interoperability and portability issues of inter-connected clouds. After categorizing the solutions, the literature has been mapped to a specific solution and a comparative analysis of the papers under the same solution has been done. The term “inter-connected clouds” has been used generically in this article to refer to any collaboration of clouds which may be from the user side (Multi-clouds or Aggregated service by Broker) or the provider side (Federated clouds or Hybrid clouds). Lastly, two closely related issues (Brokers and Meta-scheduling) and the remaining challenges of inter-connected clouds are discussed.</jats:p>

<jats:p>Ray tracing has long been considered as the next-generation technology for graphics rendering. Recently, there has been strong momentum to adopt ray tracing--based rendering techniques on consumer-level platforms due to the inability of further enhancing user experience by increasing display resolution. On the other hand, the computing workload of ray tracing is still overwhelming. A 10-fold performance gap has to be narrowed for real-time applications, even on the latest graphics processing units (GPUs). As a result, hardware acceleration techniques are critical to delivering a satisfying level performance while at the same time meeting an acceptable power budget. A large body of research on ray-tracing hardware has been proposed over the past decade. This article is aimed at providing a timely survey on hardware techniques to accelerate the ray-tracing algorithm. First, a quantitative profiling on the ray-tracing workload is presented. We then review hardware techniques for the main functional blocks in a ray-tracing pipeline. On such a basis, the ray-tracing microarchitectures for both ASIC and processors are surveyed by following a systematic taxonomy.</jats:p>

<jats:p>Activity recognition aims to provide accurate and opportune information on people’s activities by leveraging sensory data available in today’s sensory rich environments. Nowadays, activity recognition has become an emerging field in the areas of pervasive and ubiquitous computing. A typical activity recognition technique processes data streams that evolve from sensing platforms such as mobile sensors, on body sensors, and/or ambient sensors. This article surveys the two overlapped areas of research of activity recognition and data stream mining. The perspective of this article is to review the adaptation capabilities of activity recognition techniques in streaming environment. Categories of techniques are identified based on different features in both data streams and activity recognition. The pros and cons of the algorithms in each category are analysed, and the possible directions of future research are indicated.</jats:p>

<jats:p>The provisioning of an efficient ultra-large scalable distributed storage system for expanding cloud applications has been a challenging job for researchers in academia and industry. In such an ultra-large-scale storage system, data are distributed on multiple storage nodes for performance, scalability, and availability. The access to this distributed data is through its metadata, maintained by multiple metadata servers. The metadata carries information about the physical address of data and access privileges. The efficiency of a storage system highly depends on effective metadata management. This research presents an extensive systematic literature analysis of metadata management techniques in storage systems. This research work will help researchers to find the significance of metadata management and important parameters of metadata management techniques for storage systems. Methodical examination of metadata management techniques developed by various industry and research groups is described. The different metadata distribution techniques lead to various taxonomies. Furthermore, the article investigates techniques based on distribution structures and key parameters of metadata management. It also presents strengths and weaknesses of individual existing techniques that will help researchers to select the most appropriate technique for specific applications. Finally, it discusses existing challenges and significant research directions in metadata management for researchers.</jats:p>

<jats:p>Digital advances have transformed the face of automatic music generation since its beginnings at the dawn of computing. Despite the many breakthroughs, issues such as the musical tasks targeted by different machines and the degree to which they succeed remain open questions. We present a functional taxonomy for music generation systems with reference to existing systems. The taxonomy organizes systems according to the purposes for which they were designed. It also reveals the inter-relatedness amongst the systems. This design-centered approach contrasts with predominant methods-based surveys and facilitates the identification of grand challenges to set the stage for new breakthroughs.</jats:p>

<jats:p>Recently, multimedia researchers have added several so-called new media to the traditional multimedia components (e.g., olfaction, haptic, and gustation). Evaluating multimedia user-perceived Quality of Experience (QoE) is already non-trivial and the addition of multisensorial media components increases this challenge. No standardized methodology exists to conduct subjective quality assessments of multisensorial media applications. To date, researchers have employed different aspects of audiovisual standards to assess user QoE of multisensorial media applications and thus, a fragmented approach exists. In this article, the authors highlight issues researchers face from numerous perspectives including applicability (or lack of) existing audiovisual standards to evaluate user QoE and lack of result comparability due to varying approaches, specific requirements of olfactory-based multisensorial media applications, and novelty associated with these applications. Finally, based on the diverse approaches in the literature and the collective experience of authors, this article provides a tutorial and recommendations on the key steps to conduct olfactory-based multisensorial media QoE evaluation.</jats:p>

<jats:p>Complex event recognition (CER) applications exhibit various types of uncertainty, ranging from incomplete and erroneous data streams to imperfect complex event patterns. We review CER techniques that handle, to some extent, uncertainty. We examine techniques based on automata, probabilistic graphical models, and first-order logic, which are the most common ones, and approaches based on Petri nets and grammars, which are less frequently used. Several limitations are identified with respect to the employed languages, their probabilistic models, and their performance, as compared to the purely deterministic cases. Based on those limitations, we highlight promising directions for future work.</jats:p>

<jats:p>The Smart Home concept integrates smart applications in the daily human life. In recent years, Smart Homes have increased security and management challenges due to the low capacity of small sensors, multiple connectivity to the Internet for efficient applications (use of big data and cloud computing), and heterogeneity of home systems, which require inexpert users to configure devices and micro-systems. This article presents current security and management approaches in Smart Homes and shows the good practices imposed on the market for developing secure systems in houses. At last, we propose future solutions for efficiently and securely managing the Smart Homes.</jats:p>

<jats:p>Mainly focused on solving abstraction problems, programming paradigms limit language expressiveness, thus leaving unexplored natural language descriptions that are implicitly expressive. Several authors have developed tools for programming with a natural language subset limited to specific domains to deal with the ambiguity occurring with artificial intelligence technique use. This article presents a review of tools and languages with naturalistic features and highlights the problems that authors have resolved and those they have not addressed, going on to discuss the fact that a “naturalistic” language based on a well-defined model is not reported.</jats:p>

<jats:p>Modeling pedestrian dynamics and their implementation in a computer are challenging and important issues in the knowledge areas of transportation and computer simulation. The aim of this article is to provide a bibliographic outlook so that the reader may have quick access to the most relevant works related to this problem. We have used three main axes to organize the article’s contents: pedestrian models, validation techniques, and multiscale approaches. The backbone of this work is the classification of existing pedestrian models; we have organized the works in the literature under five categories, according to the techniques used for implementing the operational level in each pedestrian model. Then the main existing validation methods, oriented to evaluate the behavioral quality of the simulation systems, are reviewed. Furthermore, we review the key issues that arise when facing multiscale pedestrian modeling, where we first focus on the behavioral scale (combinations of micro and macro pedestrian models) and second on the scale size (from individuals to crowds). The article begins by introducing the main characteristics of walking dynamics and its analysis tools and concludes with a discussion about the contributions that different knowledge fields can make in the near future to this exciting area.</jats:p>