7,259 research outputs found

    Security and Privacy Problems in Voice Assistant Applications: A Survey

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    Voice assistant applications have become omniscient nowadays. Two models that provide the two most important functions for real-life applications (i.e., Google Home, Amazon Alexa, Siri, etc.) are Automatic Speech Recognition (ASR) models and Speaker Identification (SI) models. According to recent studies, security and privacy threats have also emerged with the rapid development of the Internet of Things (IoT). The security issues researched include attack techniques toward machine learning models and other hardware components widely used in voice assistant applications. The privacy issues include technical-wise information stealing and policy-wise privacy breaches. The voice assistant application takes a steadily growing market share every year, but their privacy and security issues never stopped causing huge economic losses and endangering users' personal sensitive information. Thus, it is important to have a comprehensive survey to outline the categorization of the current research regarding the security and privacy problems of voice assistant applications. This paper concludes and assesses five kinds of security attacks and three types of privacy threats in the papers published in the top-tier conferences of cyber security and voice domain.Comment: 5 figure

    Deep Transfer Learning Applications in Intrusion Detection Systems: A Comprehensive Review

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    Globally, the external Internet is increasingly being connected to the contemporary industrial control system. As a result, there is an immediate need to protect the network from several threats. The key infrastructure of industrial activity may be protected from harm by using an intrusion detection system (IDS), a preventive measure mechanism, to recognize new kinds of dangerous threats and hostile activities. The most recent artificial intelligence (AI) techniques used to create IDS in many kinds of industrial control networks are examined in this study, with a particular emphasis on IDS-based deep transfer learning (DTL). This latter can be seen as a type of information fusion that merge, and/or adapt knowledge from multiple domains to enhance the performance of the target task, particularly when the labeled data in the target domain is scarce. Publications issued after 2015 were taken into account. These selected publications were divided into three categories: DTL-only and IDS-only are involved in the introduction and background, and DTL-based IDS papers are involved in the core papers of this review. Researchers will be able to have a better grasp of the current state of DTL approaches used in IDS in many different types of networks by reading this review paper. Other useful information, such as the datasets used, the sort of DTL employed, the pre-trained network, IDS techniques, the evaluation metrics including accuracy/F-score and false alarm rate (FAR), and the improvement gained, were also covered. The algorithms, and methods used in several studies, or illustrate deeply and clearly the principle in any DTL-based IDS subcategory are presented to the reader

    'Exarcheia doesn't exist': Authenticity, Resistance and Archival Politics in Athens

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    My thesis investigates the ways people, materialities and urban spaces interact to form affective ecologies and produce historicity. It focuses on the neighbourhood of Exarcheia, Athens’ contested political topography par excellence, known for its production of radical politics of discontent and resistance to state oppression and eoliberal capitalism. Embracing Exarcheia’s controversial status within Greek vernacular, media and state discourses, this thesis aims to unpick the neighbourhoods’ socio-spatial assemblage imbued with affect and formed through the numerous (mis)understandings and (mis)interpretations rooted in its turbulent political history. Drawing on theory on urban spaces, affect, hauntology and archival politics, I argue for Exarcheia as an unwavering archival space composed of affective chronotopes – (in)tangible loci that defy space and temporality. I posit that the interwoven narratives and materialities emerging in my fieldwork are persistently – and perhaps obsessively – reiterating themselves and remaining imprinted on the neighbourhood’s landscape as an incessant reminder of violent histories that the state often seeks to erase and forget. Through this analysis, I contribute to understandings of place as a primary ethnographic ‘object’ and the ways in which place forms complex interactions and relationships with social actors, shapes their subjectivities, retains and bestows their memories and senses of historicity

    Simultaneous Localization And Mapping for robots: an experimental analysis using ROS

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    The field of robotics has seen major improvements in the past few decades. One of the most important problem researchers all around the world tried to solve is how to make a mobile robot completely autonomous. One important step to achieve this goal is to create robots that can navigate an unknown environment and, using several sensors, build a map of it, locating themselves on the map. This particular problem takes the name of Simultaneous Localization And Mapping (SLAM) and it is very important for different scenarios, such as a mobile robot that navigates an indoor environment, where GPS location cannot perform well. Theoretically, this problem can be considered solved, since several solutions have been proposed in the literature, but in practice these solutions perform sufficiently well only under particular condition, such as when the environment is static and its dimension is limited. In real world instead, the environment can change, objects can be moved, and external factors can modify the appearance of a place, making the localization of the robot very uncertain. Therefore, in practice, a long-term SLAM is an unsolved problem and it is an open field of research. A practical problem for which a definitive solution hasn’t been proposed yet is the Loop Closure Detection (LCD) issue, that is necessary to achieve a real long-term SLAM, and it is the ability of the robot to recognize places previously visited. There are many solutions proposed in the literature, but it is very challenging for a robot to recognize the same place at different time in the day, or in different seasons, or again when the particular location is not visited for long time. During the years, several practice SLAM solutions have been implemented, but a really long-term SLAM hasn’t been reached yet. In this thesis a comparison is made between two mature SLAM approaches, highlighting their criticalities and possible improvements in view of a long-term SLAM

    The Future of Work and Digital Skills

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    The theme for the events was "The Future of Work and Digital Skills". The 4IR caused a hollowing out of middle-income jobs (Frey & Osborne, 2017) but COVID-19 exposed the digital gap as survival depended mainly on digital infrastructure and connectivity. Almost overnight, organizations that had not invested in a digital strategy suddenly realized the need for such a strategy and the associated digital skills. The effects have been profound for those who struggled to adapt, while those who stepped up have reaped quite the reward.Therefore, there are no longer certainties about what the world will look like in a few years from now. However, there are certain ways to anticipate the changes that are occurring and plan on how to continually adapt to an increasingly changing world. Certain jobs will soon be lost and will not come back; other new jobs will however be created. Using data science and other predictive sciences, it is possible to anticipate, to the extent possible, the rate at which certain jobs will be replaced and new jobs created in different industries. Accordingly, the collocated events sought to bring together government, international organizations, academia, industry, organized labour and civil society to deliberate on how these changes are occurring in South Africa, how fast they are occurring and what needs to change in order to prepare society for the changes.Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) British High Commission (BHC)School of Computin

    AIUCD 2022 - Proceedings

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    L’undicesima edizione del Convegno Nazionale dell’AIUCD-Associazione di Informatica Umanistica ha per titolo Culture digitali. Intersezioni: filosofia, arti, media. Nel titolo è presente, in maniera esplicita, la richiesta di una riflessione, metodologica e teorica, sull’interrelazione tra tecnologie digitali, scienze dell’informazione, discipline filosofiche, mondo delle arti e cultural studies

    Implicaciones evolutivas de la transmisión colectiva de virus

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    Es habitual asumir en virología que las partículas virales dispersan de forma libre e independiente durante su transmisión entre células, tejidos, órganos y hospedadores. Sin embargo, esta visión ha sido cuestionada recientemente por la caracterización de múltiples estrategias que los virus emplean para transmitirse colectivamente. Entre ellas se encuentran las llamadas unidades infecciosas colectivas, que incluyen agregados virales, viriones poliploides, vesículas extracelulares o estructuras específicas como los cuerpos de oclusión; pero también diversos modos de transmisión directa y masiva de viriones entre células. En principio, la agrupación de la progenie viral disminuye el número de unidades infecciosas y, por tanto, la capacidad dispersiva de los virus. En consecuencia, para ser selectivamente favorable, la transmisión colectiva debe proporcionar beneficios que compensen su coste. Debido a que todas estas estrategias incrementan la multiplicidad de infección celular, al margen de la densidad de la población viral y del efecto de los cuellos de botella, los virus podrían beneficiarse de interactuar cooperativamente en coinfección. Por ejemplo, la entrada de múltiples genomas virales en la célula podría acelerar el ciclo infectivo y proporcionar una ventaja al virus para superar barreras tempranas frente a la infección o adelantarse a la respuesta antiviral de la célula. Por otro lado, en este mismo contexto, distintas variantes virales podrían interactuar de forma cooperativa (cooperación heterotípica) a través de la complementación genética, la división de labores o distintos tipos de interacciones sinérgicas. No obstante, interacciones como la dominancia negativa y la interferencia también pueden ocurrir, y podrían frustrar la cooperación y promover el conflicto viral. La teoría de la evolución social, ya aplicada con gran éxito al estudio de microorganismos, representa el marco teórico adecuado para analizar, comprender y predecir la dinámica evolutiva de estas interacciones virales. En esta tesis hemos explorado las implicaciones de la transmisión colectiva para la dinámica replicativa de los virus en coinfección y hemos empleado los agregados que forma el virus de la estomatitis vesicular (VSV) al ser incubado en saliva como modelo de estudio para determinar las consecuencias de la transmisión colectiva sobre la eficacia biológica viral. En primer lugar, hemos desarrollado modelos matemáticos y simulaciones que describen la replicación viral para estudiar la dinámica intracelular de las infecciones colectivas. Estos modelos muestran que la replicación es un proceso cooperativo, pues la entrada de múltiples genomas virales en una misma célula adelanta desproporcionadamente el ciclo infectivo, lo que puede acelerar la liberación de progenie viral e incrementar sinérgicamente el éxito infectivo. Los efectos cooperativos de la replicación residen en la realimentación positiva no lineal que los genomas virales establecen con los productos génicos que codifican, lo cual debería ser una característica común entre los virus. De acuerdo con ello, validamos nuestros resultados en modelos más complejos de virus específicos, pero también experimentalmente, empleando seis virus distintos que infectan mamíferos. En segundo lugar, hemos comparado el crecimiento y la eficacia biológica de los viriones libres de VSV frente a agregados en ocho líneas celulares. Para un mismo número de partículas virales, la agregación tendía a acelerar la liberación de progenie e incrementar la eficacia biológica en competencia en la mayoría de líneas celulares analizadas. Estos efectos no parecían depender de la complementación genética entre mutantes deletéreos de nuestras poblaciones virales, pues la ventaja de agregar se revirtió al incrementar la carga mutacional mediante mutagénesis química. No obstante, correlacionaron negativamente con la permisividad de las células a la infección y positivamente con la capacidad inmunitaria innata de las células, indicando la mayor capacidad de los agregados para superar barreras tempranas frente a la infección. En tercer lugar, utilizamos la evolución experimental para analizar las consecuencias no inmediatas de la agregación. A pesar de mantener un régimen de baja densidad viral, la agregación promovió una invasión rápida de las poblaciones virales por partículas interferentes defectivas (DIPs), que detectamos mediante distintas metodologías (citometría de flujo, secuenciación masiva, ensayos de reducción de título, RT-qPCRs y microscopía electrónica). Por tanto, concluimos que la agregación de VSV produce un aumento inmediato en la eficacia del virus, pero incurre en costes posteriores a causa de la proliferación de DIPs. Este escenario dificulta enormemente la evolución de interacciones cooperativas entre variantes virales y promueve un régimen de transmisión colectiva episódico, por ejemplo, durante la transmisión entre hospedadores.It is commonly assumed in virology that viral particles disperse freely and independently during their transmission between cells, tissues, organs and hosts. However, this view has recently been challenged by the characterization of multiple strategies that viruses use for their collective transmission. These include the so-called collective infectious units, such as viral aggregates, polyploid virions, extracellular vesicles or other specific structures such as occlusion bodies; but also a variety of modes for the direct and massive transmission of virions between cells. In principle, the clustering of viral progeny decreases the number of infectious units and thus the ability of viruses to disperse. Consequently, to be selectively advantageous, collective transmission must provide benefits that offset its cost. Because all of these strategies increase the cellular multiplicity of infection, regardless of viral population density and bottleneck effects, viruses could benefit from cooperatively interacting in coinfection. For example, the entry of multiple viral genomes into the cell could accelerate the infectious cycle and provide an advantage for the virus to overcome early infection barriers or preempt the cellular antiviral response. On the other hand, in this same context, different viral variants could interact in a cooperative manner (heterotypic cooperation) through genetic complementation, division of labor or different types of synergistic interactions. However, interactions such as negative dominance and interference can also occur, and could thwart cooperation and promote viral conflict. The theory of social evolution, which has already been applied with great success to the study of microorganisms, represents the appropriate theoretical framework to analyze, understand and predict the evolutionary dynamics of these viral interactions. In this thesis we have explored the implications of collective transmission for the replicative dynamics of co-infecting viruses and have used viral aggregates formed by incubating vesicular stomatitis virus (VSV) in saliva as a study model to determine the consequences of collective transmission on viral fitness. First, we have developed mathematical models and simulations describing viral replication to study the intracellular dynamics of collective infections. These models show that replication is a cooperative process, as the entry of multiple viral genomes into the same cell disproportionately accelerates the infectious cycle, which in turn can accelerate the release of viral progeny and synergistically increase infectious success. The cooperative effects of replication arise from the nonlinear positive feedback that viral genomes establish with the gene products they encode, which should be a common feature among viruses. Accordingly, we validated our results in more complex models of specific viruses, but also experimentally, using six different mammalian viruses. Second, we compared the growth and fitness of free VSV virions versus aggregates in eight cell lines. For the same number of viral particles, aggregation tended to accelerate progeny release and increase fitness in competition in most of the cell lines tested. These effects did not appear to depend on genetic complementation between deleterious mutants of our viral populations, as the advantage of aggregation was reversed by increasing the mutational load by chemical mutagenesis. However, they correlated negatively with cell permissivity to infection and positively with the innate immune response of the cells, indicating a higher capacity of aggregates to overcome early barriers to infection. Third, we used experimental evolution to analyze the non-immediate consequences of aggregation. Despite maintaining a low viral density regime, aggregation promoted a rapid invasion of viral populations by defective interfering particles (DIPs), which we detected by different methodologies (flow cytometry, deep sequencing, yield reduction assays, RT-qPCRs and electron microscopy). Therefore, we conclude that VSV aggregation results in an immediate increase in virus efficacy, but incurs in long-term costs due to the proliferation of DIPs. This scenario greatly hinders the evolution of cooperative interactions between viral variants and favors an episodic collective transmission regime, for instance, during inter-host transmission

    Joint optimization of depth and ego-motion for intelligent autonomous vehicles

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    The three-dimensional (3D) perception of autonomous vehicles is crucial for localization and analysis of the driving environment, while it involves massive computing resources for deep learning, which can't be provided by vehicle-mounted devices. This requires the use of seamless, reliable, and efficient massive connections provided by the 6G network for computing in the cloud. In this paper, we propose a novel deep learning framework with 6G enabled transport system for joint optimization of depth and ego-motion estimation, which is an important task in 3D perception for autonomous driving. A novel loss based on feature map and quadtree is proposed, which uses feature value loss with quadtree coding instead of photometric loss to merge the feature information at the texture-less region. Besides, we also propose a novel multi-level V-shaped residual network to estimate the depths of the image, which combines the advantages of V-shaped network and residual network, and solves the problem of poor feature extraction results that may be caused by the simple fusion of low-level and high-level features. Lastly, to alleviate the influence of image noise on pose estimation, we propose a number of parallel sub-networks that use RGB image and its feature map as the input of the network. Experimental results show that our method significantly improves the quality of the depth map and the localization accuracy and achieves the state-of-the-art performance

    Estudo do IPFS como protocolo de distribuição de conteúdos em redes veiculares

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    Over the last few years, vehicular ad-hoc networks (VANETs) have been the focus of great progress due to the interest in autonomous vehicles and in distributing content not only between vehicles, but also to the Cloud. Performing a download/upload to/from a vehicle typically requires the existence of a cellular connection, but the costs associated with mobile data transfers in hundreds or thousands of vehicles quickly become prohibitive. A VANET allows the costs to be several orders of magnitude lower - while keeping the same large volumes of data - because it is strongly based in the communication between vehicles (nodes of the network) and the infrastructure. The InterPlanetary File System (IPFS) is a protocol for storing and distributing content, where information is addressed by its content, instead of its location. It was created in 2014 and it seeks to connect all computing devices with the same system of files, comparable to a BitTorrent swarm exchanging Git objects. It has been tested and deployed in wired networks, but never in an environment where nodes have intermittent connectivity, such as a VANET. This work focuses on understanding IPFS, how/if it can be applied to the vehicular network context, and comparing it with other content distribution protocols. In this dissertation, IPFS has been tested in a small and controlled network to understand its working applicability to VANETs. Issues such as neighbor discoverability times and poor hashing performance have been addressed. To compare IPFS with other protocols (such as Veniam’s proprietary solution or BitTorrent) in a relevant way and in a large scale, an emulation platform was created. The tests in this emulator were performed in different times of the day, with a variable number of files and file sizes. Emulated results show that IPFS is on par with Veniam’s custom V2V protocol built specifically for V2V, and greatly outperforms BitTorrent regarding neighbor discoverability and data transfers. An analysis of IPFS’ performance in a real scenario was also conducted, using a subset of STCP’s vehicular network in Oporto, with the support of Veniam. Results from these tests show that IPFS can be used as a content dissemination protocol, showing it is up to the challenge provided by a constantly changing network topology, and achieving throughputs up to 2.8 MB/s, values similar or in some cases even better than Veniam’s proprietary solution.Nos últimos anos, as redes veiculares (VANETs) têm sido o foco de grandes avanços devido ao interesse em veículos autónomos e em distribuir conteúdos, não só entre veículos mas também para a "nuvem" (Cloud). Tipicamente, fazer um download/upload de/para um veículo exige a utilização de uma ligação celular (SIM), mas os custos associados a fazer transferências com dados móveis em centenas ou milhares de veículos rapidamente se tornam proibitivos. Uma VANET permite que estes custos sejam consideravelmente inferiores - mantendo o mesmo volume de dados - pois é fortemente baseada na comunicação entre veículos (nós da rede) e a infraestrutura. O InterPlanetary File System (IPFS - "sistema de ficheiros interplanetário") é um protocolo de armazenamento e distribuição de conteúdos, onde a informação é endereçada pelo conteúdo, em vez da sua localização. Foi criado em 2014 e tem como objetivo ligar todos os dispositivos de computação num só sistema de ficheiros, comparável a um swarm BitTorrent a trocar objetos Git. Já foi testado e usado em redes com fios, mas nunca num ambiente onde os nós têm conetividade intermitente, tal como numa VANET. Este trabalho tem como foco perceber o IPFS, como/se pode ser aplicado ao contexto de rede veicular e compará-lo a outros protocolos de distribuição de conteúdos. Numa primeira fase o IPFS foi testado numa pequena rede controlada, de forma a perceber a sua aplicabilidade às VANETs, e resolver os seus primeiros problemas como os tempos elevados de descoberta de vizinhos e o fraco desempenho de hashing. De modo a poder comparar o IPFS com outros protocolos (tais como a solução proprietária da Veniam ou o BitTorrent) de forma relevante e em grande escala, foi criada uma plataforma de emulação. Os testes neste emulador foram efetuados usando registos de mobilidade e conetividade veicular de alturas diferentes de um dia, com um número variável de ficheiros e tamanhos de ficheiros. Os resultados destes testes mostram que o IPFS está a par do protocolo V2V da Veniam (desenvolvido especificamente para V2V e VANETs), e que o IPFS é significativamente melhor que o BitTorrent no que toca ao tempo de descoberta de vizinhos e transferência de informação. Uma análise do desempenho do IPFS em cenário real também foi efetuada, usando um pequeno conjunto de nós da rede veicular da STCP no Porto, com o apoio da Veniam. Os resultados destes testes demonstram que o IPFS pode ser usado como protocolo de disseminação de conteúdos numa VANET, mostrando-se adequado a uma topologia constantemente sob alteração, e alcançando débitos até 2.8 MB/s, valores parecidos ou nalguns casos superiores aos do protocolo proprietário da Veniam.Mestrado em Engenharia de Computadores e Telemátic
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