Catálogo de publicaciones - revistas

<jats:p>Internet geolocation technology aims to determine the physical (geographic) location of Internet users and devices. It is currently proposed or in use for a wide variety of purposes, including targeted marketing, restricting digital content sales to authorized jurisdictions, and security applications such as reducing credit card fraud. This raises questions about the veracity of claims of accurate and reliable geolocation. We provide a survey of Internet geolocation technologies with an emphasis on adversarial contexts; that is, we consider how this technology performs against a knowledgeable adversary whose goal is to evade geolocation. We do so by examining first the limitations of existing techniques, and then, from this base, determining how best to evade existing geolocation techniques. We also consider two further geolocation techniques which may be of use even against adversarial targets: (1) the extraction of client IP addresses using functionality introduced in the 1.5 Java API, and (2) the collection of round-trip times using HTTP refreshes. These techniques illustrate that the seemingly straightforward technique of evading geolocation by relaying traffic through a proxy server (or network of proxy servers) is not as straightforward as many end-users might expect. We give a demonstration of this for users of the popular Tor anonymizing network.</jats:p>

<jats:p>Reputation systems provide mechanisms to produce a metric encapsulating reputation for a given domain for each identity within the system. These systems seek to generate an accurate assessment in the face of various factors including but not limited to unprecedented community size and potentially adversarial environments.</jats:p> <jats:p>We focus on attacks and defense mechanisms in reputation systems. We present an analysis framework that allows for the general decomposition of existing reputation systems. We classify attacks against reputation systems by identifying which system components and design choices are the targets of attacks. We survey defense mechanisms employed by existing reputation systems. Finally, we analyze several landmark systems in the peer-to-peer domain, characterizing their individual strengths and weaknesses. Our work contributes to understanding (1) which design components of reputation systems are most vulnerable, (2) what are the most appropriate defense mechanisms and (3) how these defense mechanisms can be integrated into existing or future reputation systems to make them resilient to attacks.</jats:p>

<jats:p>An emerging area of research studies the complexity of constraint satisfaction problems under restricted constraint languages. This article gives a self-contained, contemporary presentation of Schaefer's theorem on Boolean constraint satisfaction, the inaugural result of this area, as well as analogs of this theorem for quantified formulas. Our exposition makes use of and may serve as an introduction to logical and algebraic tools that have recently come into focus.</jats:p>

<jats:p>The past two decades have seen a growing interest in methods for anonymous communication on the Internet, both from the academic community and the general public. Several system designs have been proposed in the literature, of which a number have been implemented and are used by diverse groups, such as journalists, human rights workers, the military, and ordinary citizens, to protect their identities on the Internet.</jats:p> <jats:p>In this work, we survey the previous research done to design, develop, and deploy systems for enabling private and anonymous communication on the Internet. We identify and describe the major concepts and technologies in the field, including mixes and mix networks, onion routing, and Dining Cryptographers networks. We will also review powerful traffic analysis attacks that have motivated improvements and variations on many of these anonymity protocols made since their introduction. Finally, we will summarize some of the major open problems in anonymous communication research and discuss possible directions for future work in the field.</jats:p>

<jats:p>We present a survey of research into automated and semiautomated computer systems for expressive performance of music. We will examine the motivation for such systems and then examine the majority of the systems developed over the last 25 years. To highlight some of the possible future directions for new research, the review uses primary terms of reference based on four elements: testing status, expressive representation, polyphonic ability, and performance creativity.</jats:p>

<jats:p>Degradation of devices has become a major issue for processor design due to continuous device shrinkage and current density increase. Transistors and wires suffer high stress, and failures may appear in the field. In particular, wires degrade mainly due to electromigration when driving current. Techniques to mitigate electromigration to some extent have been proposed from the circuit point of view, but much effort is still required from the microarchitecture side to enable wire scaling in future technologies.</jats:p> <jats:p>This survey brings to the microarchitecture community a comprehensive study of the causes and implications of electromigration in digital circuits and describes the challenges that must be faced to mitigate electromigration by means of microarchitectural solutions.</jats:p>

<jats:p>Smart meeting systems, which record meetings and analyze the generated audio--visual content for future viewing, have been a topic of great interest in recent years. A successful smart meeting system relies on various technologies, ranging from devices and algorithms to architecture. This article presents a condensed survey of existing research and technologies, including smart meeting system architecture, meeting capture, meeting recognition, semantic processing, and evaluation methods. It aims at providing an overview of underlying technologies to help understand the key design issues of such systems. This article also describes various open issues as possible ways to extend the capabilities of current smart meeting systems.</jats:p>

<jats:p>Achieving uniform access to media objects in heterogeneous media repositories requires dealing with the problem of metadata interoperability. Currently there exist many interoperability techniques, with quite varying potential for resolving the structural and semantic heterogeneities that can exist between metadata stored in distinct repositories. Besides giving a general overview of the field of metadata interoperability, we provide a categorization of existing interoperability techniques, describe their characteristics, and compare their quality by analyzing their potential for resolving various types of heterogeneities. Based on our work, domain experts and technicians get an overview and categorization of existing metadata interoperability techniques and can select the appropriate approach for their specific metadata integration scenarios. Our analysis explicitly shows that metadata mapping is the appropriate technique in integration scenarios where an agreement on a certain metadata standard is not possible.</jats:p>

<jats:p>The increasing relevance of areas such as real-time and embedded systems, pervasive computing, hybrid systems control, and biological and social systems modeling is bringing a growing attention to the temporal aspects of computing, not only in the computer science domain, but also in more traditional fields of engineering.</jats:p> <jats:p>This article surveys various approaches to the formal modeling and analysis of the temporal features of computer-based systems, with a level of detail that is also suitable for nonspecialists. In doing so, it provides a unifying framework, rather than just a comprehensive list of formalisms.</jats:p> <jats:p>The article first lays out some key dimensions along which the various formalisms can be evaluated and compared. Then, a significant sample of formalisms for time modeling in computing are presented and discussed according to these dimensions. The adopted perspective is, to some extent, historical, going from “traditional” models and formalisms to more modern ones.</jats:p>