Catálogo de publicaciones - revistas

<jats:p>Cryptographic algorithms have been used not only to create robust ciphertexts but also to generate cryptograms that, contrary to the classic goal of cryptography, are meant to be broken. These cryptograms, generally called puzzles, require the use of a certain amount of resources to be solved, hence introducing a cost that is often regarded as a time delay—though it could involve other metrics as well, such as bandwidth. These powerful features have made puzzles the core of many security protocols, acquiring increasing importance in the IT security landscape. The concept of a puzzle has subsequently been extended to other types of schemes that do not use cryptographic functions, such as CAPTCHAs, which are used to discriminate humans from machines. Overall, puzzles have experienced a renewed interest with the advent of Bitcoin, which uses a CPU-intensive puzzle as proof of work. In this article, we provide a comprehensive study of the most important puzzle construction schemes available in the literature, categorizing them according to several attributes, such as resource type, verification type, and applications. We have redefined the term puzzle by collecting and integrating the scattered notions used in different works, to cover all the existing applications. Moreover, we provide an overview of the possible applications, identifying key requirements and different design approaches. Finally, we highlight the features and limitations of each approach, providing a useful guide for the future development of new puzzle schemes.</jats:p>

<jats:p>Due to technology scaling and harsh environments, a wide range of fault-tolerant techniques exists to deal with the error occurrences. Selecting a fault-tolerant technique is not trivial, whereas more than the necessary overhead is usually inserted during the system design. To avoid over-designing, it is necessary to have an in-depth understanding of the available design options. However, an exhaustive listing is neither possible to create nor efficient to use due to its prohibitive size. In this work, we present a top-down binary tree classification for error detection and correction techniques. At each split, the design space is clearly divided into two complementary parts using one single attribute, compared with existing classifications that use splits with multiple attributes. A leaf inherits all the attributes of its ancestors from the root to the leaf. A technique is decomposed into primitive components, each one belonging to a different leaf. The single attribute splits can be used to efficiently compare the techniques and to prune the incompatible parts of the design space during the design of a technique. This essential single attribute division of the design space is required for the improvement of the techniques and for novel contributions to the fault-tolerance domain.</jats:p>

<jats:p>The model of membrane computing, also known under the name of P systems, is a bio-inspired large-scale parallel computing paradigm having a good potential for the design of massively parallel algorithms. For its implementation it is very natural to choose hardware platforms that have important inherent parallelism, such as field-programmable gate arrays (FPGAs) or compute unified device architecture (CUDA)-enabled graphic processing units (GPUs). This article performs an overview of all existing approaches of hardware implementation in the area of P systems. The quantitative and qualitative attributes of FPGA-based implementations and CUDA-enabled GPU-based simulations are compared to evaluate the two methodologies.</jats:p>

<jats:p>Multi-core devices are envisioned to support the development of next-generation safety-critical systems, enabling the on-chip integration of functions of different criticality. This integration provides multiple system-level potential benefits such as cost, size, power, and weight reduction. However, safety certification becomes a challenge and several fundamental safety technical requirements must be addressed, such as temporal and spatial independence, reliability, and diagnostic coverage. This survey provides a categorization and overview at different device abstraction levels (nanoscale, component, and device) of selected key research contributions that support the compliance with these fundamental safety requirements.</jats:p>

<jats:p>In this article, we encompass an analysis of the recent advances in parallel genetic algorithms (PGAs). We have selected these algorithms because of the deep interest in many research fields for techniques that can face complex applications where running times and other computational resources are greedily consumed by present solvers, and PGAs act then as efficient procedures that fully use modern computational platforms at the same time that allow the resolution of cutting-edge open problems. We have faced this survey on PGAs with the aim of helping newcomers or busy researchers who want to have a wide vision on the field. Then, we discuss the most well-known models and their implementations from a recent (last six years) and useful point of view: We discuss on highly cited articles, keywords, the venues where they can be found, a very comprehensive (and new) taxonomy covering different research domains involved in PGAs, and a set of recent applications. We also introduce a new vision on open challenges and try to give hints that guide practitioners and specialized researchers. Our conclusion is that there are many advantages to using these techniques and lots of potential interactions to other evolutionary algorithms; as well, we contribute to creating a body of knowledge in PGAs by summarizing them in a structured way, so the reader can find this article useful for practical research, graduate teaching, and as a pedagogical guide to this exciting domain.</jats:p>

<jats:p>Attribute-based encryption (ABE) for cloud computing access control is reviewed in this article. A taxonomy and comprehensive assessment criteria of ABE are first proposed. In the taxonomy, ABE schemes are assorted into key-policy ABE (KP-ABE) schemes, ciphertext-policy ABE (CP-ABE) schemes, anti-quantum ABE schemes, and generic constructions. In accordance with cryptographically functional features, CP-ABE is further divided into nine subcategories with regard to basic functionality, revocation, accountability, policy hiding, policy updating, multi-authority, hierarchy, offline computation, and outsourced computation. In addition, a systematical methodology for discussing and comparing existing ABE schemes is proposed. For KP-ABE and each type of CP-ABE, the corresponding access control scenario is presented and explained by concrete examples. Specifically, the syntax of ABE is given followed by the adversarial model and security goals. ABE schemes are discussed according to the design strategies and special features and are compared in the light of the proposed assessment criteria with respect to security and performance. Compared to related state-of-the-art survey papers, this article not only provides a broader 12 categories of ABE schemes, but also makes a more comprehensive and holistic comparison. Finally, a number of open research challenges in ABE are pointed out.</jats:p>

<jats:p> As a recent innovation, network functions virtualization (NFV)—with its core concept of replacing hardware middleboxes with software network functions (NFs) implemented in commodity servers—promises cost savings and flexibility benefits. However, transitioning NFs from special-purpose hardware to commodity servers has turned out to be more challenging than expected, as it inevitably incurs performance penalties due to bottlenecks in both software and hardware. To achieve performance comparable to hardware middleboxes, there is a strong demand for a speedup in NF processing, which plays a crucial role in the success of NFV. In this article, we study the performance challenges that exist in general-purpose servers and simultaneously summarize the typical performance bottlenecks in NFV. Through reviewing the progress in the field of <jats:italic>NFV acceleration</jats:italic> , we present a new taxonomy of the state-of-the-art efforts according to various acceleration approaches. We discuss the surveyed works and identify the respective advantages and disadvantages in each category. We then discuss the products, solutions, and projects emerged in industry. We also present a gap analysis to improve current solutions and highlight promising research trends that can be explored in the future. </jats:p>

<jats:p> The Internet of Things (IoT) paradigm is being rapidly adopted for the creation of smart environments in various domains. The IoT-enabled cyber-physical systems associated with smart city, healthcare, Industry 4.0 and Agtech handle a huge volume of data and require data processing services from different types of applications in real time. The Cloud-centric execution of IoT applications barely meets such requirements as the Cloud datacentres reside at a multi-hop distance from the IoT devices. <jats:italic>Fog computing</jats:italic> , an extension of Cloud at the edge network, can execute these applications closer to data sources. Thus, Fog computing can improve application service delivery time and resist network congestion. However, the Fog nodes are highly distributed and heterogeneous, and most of them are constrained in resources and spatial sharing. Therefore, efficient management of applications is necessary to fully exploit the capabilities of Fog nodes. In this work, we investigate the existing application management strategies in Fog computing and review them in terms of architecture, placement and maintenance. Additionally, we propose a comprehensive taxonomy and highlight the research gaps in Fog-based application management. We also discuss a perspective model and provide future research directions for further improvement of application management in Fog computing. </jats:p>

<jats:p>Machine Learning (ML) and Internet of Things (IoT) are complementary advances: ML techniques unlock the potential of IoT with intelligence, and IoT applications increasingly feed data collected by sensors into ML models, thereby employing results to improve their business processes and services. Hence, orchestrating ML pipelines that encompass model training and implication involved in the holistic development lifecycle of an IoT application often leads to complex system integration. This article provides a comprehensive and systematic survey of the development lifecycle of ML-based IoT applications. We outline the core roadmap and taxonomy and subsequently assess and compare existing standard techniques used at individual stages.</jats:p>

<jats:p>The maintenance of efficient and robust overlay networks is one of the most fundamental and reoccurring themes in networking. This article presents a survey of state-of-the-art algorithms to design and repair overlay networks in a distributed manner. In particular, we discuss basic algorithmic primitives to preserve connectivity, review algorithms for the fundamental problem of graph linearization, and then survey self-stabilizing algorithms for metric and scalable topologies. We also identify open problems and avenues for future research.</jats:p>