104 research outputs found

    Contribution to the construction of fingerprinting and watermarking schemes to protect mobile agents and multimedia content

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    The main characteristic of fingerprinting codes is the need of high error-correction capacity due to the fact that they are designed to avoid collusion attacks which will damage many symbols from the codewords. Moreover, the use of fingerprinting schemes depends on the watermarking system that is used to embed the codeword into the content and how it honors the marking assumption. In this sense, even though fingerprinting codes were mainly used to protect multimedia content, using them on software protection systems seems an option to be considered. This thesis, studies how to use codes which have iterative-decoding algorithms, mainly turbo-codes, to solve the fingerprinting problem. Initially, it studies the effectiveness of current approaches based on concatenating tradicioanal fingerprinting schemes with convolutional codes and turbo-codes. It is shown that these kind of constructions ends up generating a high number of false positives. Even though this thesis contains some proposals to improve these schemes, the direct use of turbo-codes without using any concatenation with a fingerprinting code as inner code has also been considered. It is shown that the performance of turbo-codes using the appropiate constituent codes is a valid alternative for environments with hundreds of users and 2 or 3 traitors. As constituent codes, we have chosen low-rate convolutional codes with maximum free distance. As for how to use fingerprinting codes with watermarking schemes, we have studied the option of using watermarking systems based on informed coding and informed embedding. It has been discovered that, due to different encodings available for the same symbol, its applicability to embed fingerprints is very limited. On this sense, some modifications to these systems have been proposed in order to properly adapt them to fingerprinting applications. Moreover the behavior and impact over a video produced as a collusion of 2 users by the YouTube’s s ervice has been s tudied. We have also studied the optimal parameters for viable tracking of users who have used YouTube and conspired to redistribute copies generated by a collusion attack. Finally, we have studied how to implement fingerprinting schemes and software watermarking to fix the problem of malicious hosts on mobile agents platforms. In this regard, four different alternatives have been proposed to protect the agent depending on whether you want only detect the attack or avoid it in real time. Two of these proposals are focused on the protection of intrusion detection systems based on mobile agents. Moreover, each of these solutions has several implications in terms of infrastructure and complexity.Els codis fingerprinting es caracteritzen per proveir una alta capacitat correctora ja que han de fer front a atacs de confabulació que malmetran una part important dels símbols de la paraula codi. D'atra banda, la utilització de codis de fingerprinting en entorns reals està subjecta a que l'esquema de watermarking que gestiona la incrustació sigui respectuosa amb la marking assumption. De la mateixa manera, tot i que el fingerprinting neix de la protecció de contingut multimèdia, utilitzar-lo en la protecció de software comença a ser una aplicació a avaluar. En aquesta tesi s'ha estudiat com aplicar codis amb des codificació iterativa, concretament turbo-codis, al problema del rastreig de traïdors en el context del fingerprinting digital. Inicialment s'ha qüestionat l'eficàcia dels enfocaments actuals en la utilització de codis convolucionals i turbo-codis que plantegen concatenacions amb esquemes habituals de fingerprinting. S'ha demostrat que aquest tipus de concatenacions portaven, de forma implícita, a una elevada probabilitat d'inculpar un usuari innocent. Tot i que s'han proposat algunes millores sobre aquests esquemes , finalment s'ha plantejat l'ús de turbocodis directament, evitant així la concatenació amb altres esquemes de fingerprinting. S'ha demostrat que, si s'utilitzen els codis constituents apropiats, el rendiment del turbo-descodificador és suficient per a ser una alternativa aplicable en entorns amb varis centenars d'usuaris i 2 o 3 confabuladors . Com a codis constituents s'ha optat pels codis convolucionals de baix ràtio amb distància lliure màxima. Pel que fa a com utilitzar els codis de fingerprinting amb esquemes de watermarking, s'ha estudiat l'opció d'utilitzar sistemes de watermarking basats en la codificació i la incrustació informada. S'ha comprovat que, degut a la múltiple codificació del mateix símbol, la seva aplicabilitat per incrustar fingerprints és molt limitada. En aquest sentit s'ha plantejat algunes modificacions d'aquests sistemes per tal d'adaptar-los correctament a aplicacions de fingerprinting. D'altra banda s'ha avaluat el comportament i l'impacte que el servei de YouTube produeix sobre un vídeo amb un fingerprint incrustat. A més , s'ha estudiat els paràmetres òptims per a fer viable el rastreig d'usuaris que han confabulat i han utilitzat YouTube per a redistribuir la copia fruït de la seva confabulació. Finalment, s'ha estudiat com aplicar els esquemes de fingerprinting i watermarking de software per solucionar el problema de l'amfitrió maliciós en agents mòbils . En aquest sentit s'han proposat quatre alternatives diferents per a protegir l'agent en funció de si és vol només detectar l'atac o evitar-lo en temps real. Dues d'aquestes propostes es centren en la protecció de sistemes de detecció d'intrusions basats en agents mòbils. Cadascuna de les solucions té diverses implicacions a nivell d'infrastructura i de complexitat.Postprint (published version

    Circular economy design visioning: exploring industrial and urban symbiosis in South African cities.

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    Doctoral Degree. University of KwaZulu-Natal, Durban.Cities of tomorrow will be at the coalface of the complex challenges posed by climate change, e.g. resource scarcity. Climate change adaptation strategies will include circular economy (CE) practices (e.g. industrial and urban symbiosis) to increase the rate of recycling technical nutrients, in turn improving the resource efficiency of cities. The study investigates industrial and urban symbiosis in South Africa. In doing so, exploring technology enabled (i.e. cyber-physical-social ecosystems) CE solutions to designing out waste in South African cities. One of the key contributions of the research is the comprehensive synthesis and testing of an iterative problem structuring, theory building and design visioning (problem-theory-design) continuum to inform CE experimentation. A mixed methods design visioning approach is developed through an experiential and iterative design practice nested in a network of interdisciplinary theoretical constructs: 1) philosophical construct – Ecological Literacy (systems thinking), 2) techno-economic construct – Third Industrial Revolution (internet-of-things enabled general purpose technology platform), and Circular Economy (industrial and urban symbiosis), and 3) design construct – properties of Ecodesign derived from the dynamic renewable design of natural ecosystems. The research argues that to construct a meaningful CE transition experiment, a logical starting point is to distil key findings from a theoretically embedded case study to inform the design of a virtual experiment and simulation sketch. Through an embedded multiple case study approach the research investigates complex resource recovery dynamics in two key waste economy sub-sectors; industrial waste management and urban informal recycling sectors in the province of KwaZulu-Natal (KZN). The case studies provide an integrated method (i.e. synthesising quantitative and qualitative knowledge) for holistic and high-resolution problem structuring. From a systems thinking perspective, key leverage points (i.e. data, information sharing and infrastructure) are identified for potential policy and technology intervention. Learnings from the case studies inform policy recommendations and CE innovation. The findings from the industrial symbiosis (IS) case study illustrate that firms and supply chain networks recognise the environmental importance of improving industrial waste management practices, however they are locked-in to end-of-pipe solutions. Firms highlighted regulation, price sensitivity, customer pressure and top management as key drivers of pro-environmental behaviour change (e.g. waste beneficiation). The findings highlight the unrealised IS potential in the South vi Durban Basin. In addition, revealing significant barriers to IS, i.e. lack of information sharing between firms and a weak regulatory environment. To increase the detection, matching and emergence of IS relationships will command the dynamic co-production of codified resource flow data; herein a big data analytics approach can be employed to construct open source platforms for interfirm information (e.g. residual resource flows) sharing and knowledge production – an industrial commons internet. The urban symbiosis case study explores the informal recycling sector in KZN analysing the instrumental role of waste pickers as primary looping agents in recovering recyclable materials from post-consumer waste and increasing the supply of recyclable materials (e.g. cardboard, paper, plastic and metal) in the secondary resources economy. Waste pickers are an important link in recycling value chains; sorting, gathering and manually transporting recyclable materials to buy-back-centres and informal collection pick up points. The case study investigates how their efficiency can be improved to stimulate greater positive environmental impacts, create decent employment opportunities, and reduce waste management costs for municipalities. The findings from the case study on waste pickers are extrapolated in a CE design visioning exercise. From a systems level perspective, the research culminates in the sketch of a virtual circular city experiment; a cyber-physical social ecosystem (CPSE) designed to increase recycling rates in cities by addressing the infrastructural needs of waste pickers. The hardware, software and social ecosystem is built out of an internet-of-things (IoT) platform. Firstly, the IoT enabled infrastructural system improves material recovery efficiencies (of post-consumer recyclable materials) by increasing connectivity between waste pickers and waste collectors. Increased connectivity allows for looping and aggregating material stock and flow data. Secondly, the integrated hardware and software infrastructure provides an automated, digitised and decentralised buy-back-transfer service – delivered through connected and solar-powered collection nodes strategically distributed throughout the city in a mesh network configuration. Thirdly, the digital platform aggregates big data and employs advanced analytics to generate actionable residual resource intelligence, consequently enabling evidence-based decision making by key stakeholders, e.g. government agencies, industry associations, recyclers and material reprocessors. To further the research agenda, the next step is structuring a real-world transition experiment based on the virtual circular city design experiment, defined as, the internet-of-waste pickers (IoWP)

    Spatial aspects of mobile ad hoc collaboration

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    Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2003.Includes bibliographical references (p. 72-76).Traditionally, communication devices are designed to overcome distance in space or time. How can personal mobile tools augment local interaction and promote spontaneous collaboration between users in proximity? Mobile ad hoc collaboration is an emerging framework that attempts to answer this question. This thesis reviews current research in mobile ad hoc collaboration, explores its precedents in art, and examines the enabling wireless communication and location sensing technology. It then proceeds to consider location, proximity and spatial organization as major factors in the development of interfaces and applications within the framework. The importance of seamless transitions between face-to-face communication and mediated communication is emphasized, and the principle of ad hoc communication group formation on the basis of proximity is proposed. The principle is demonstrated in a prototype wearable system for synchronous voice messaging.by Ivan Sergeyevich Chardin.S.M

    Blue sky legislation

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    Thesis (M.A.)--University of Kansas, Economics, 1916. ; Includes bibliographical references

    Pastoralism and Development in Africa

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    Once again, the Horn of Africa has been in the headlines. And once again the news has been bad: drought, famine, conflict, hunger, suffering and death. The finger of blame has been pointed in numerous directions: to the changing climate, to environmental degradation, to overpopulation, to geopolitics and conflict, to aid agency failures, and more. But it is not all disaster and catastrophe. Many successful development efforts at ‘the margins’ often remain hidden, informal, sometimes illegal; and rarely in line with standard development prescriptions. If we shift our gaze from the capital cities to the regional centres and their hinterlands, then a very different perspective emerges. These are the places where pastoralists live. They have for centuries struggled with drought, conflict and famine. They are resourceful, entrepreneurial and innovative peoples. Yet they have been ignored and marginalised by the states that control their territory and the development agencies who are supposed to help them. This book argues that, while we should not ignore the profound difficulties of creating secure livelihoods in the Greater Horn of Africa, there is much to be learned from development successes, large and small. This book will be of great interest to students and scholars with an interest in development studies and human geography, with a particular emphasis on Africa. It will also appeal to development policy-makers and practitioners

    Dutkat: A Privacy-Preserving System for Automatic Catch Documentation and Illegal Activity Detection in the Fishing Industry

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    United Nations' Sustainable Development Goal 14 aims to conserve and sustainably use the oceans and their resources for the benefit of people and the planet. This includes protecting marine ecosystems, preventing pollution, and overfishing, and increasing scientific understanding of the oceans. Achieving this goal will help ensure the health and well-being of marine life and the millions of people who rely on the oceans for their livelihoods. In order to ensure sustainable fishing practices, it is important to have a system in place for automatic catch documentation. This thesis presents our research on the design and development of Dutkat, a privacy-preserving, edge-based system for catch documentation and detection of illegal activities in the fishing industry. Utilising machine learning techniques, Dutkat can analyse large amounts of data and identify patterns that may indicate illegal activities such as overfishing or illegal discard of catch. Additionally, the system can assist in catch documentation by automating the process of identifying and counting fish species, thus reducing potential human error and increasing efficiency. Specifically, our research has consisted of the development of various components of the Dutkat system, evaluation through experimentation, exploration of existing data, and organization of machine learning competitions. We have also implemented it from a compliance-by-design perspective to ensure that the system is in compliance with data protection laws and regulations such as GDPR. Our goal with Dutkat is to promote sustainable fishing practices, which aligns with the Sustainable Development Goal 14, while simultaneously protecting the privacy and rights of fishing crews

    Pastoralism and Development in Africa

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    Once again, the Horn of Africa has been in the headlines. And once again the news has been bad: drought, famine, conflict, hunger, suffering and death. The finger of blame has been pointed in numerous directions: to the changing climate, to environmental degradation, to overpopulation, to geopolitics and conflict, to aid agency failures, and more. But it is not all disaster and catastrophe. Many successful development efforts at ‘the margins’ often remain hidden, informal, sometimes illegal; and rarely in line with standard development prescriptions. If we shift our gaze from the capital cities to the regional centres and their hinterlands, then a very different perspective emerges. These are the places where pastoralists live. They have for centuries struggled with drought, conflict and famine. They are resourceful, entrepreneurial and innovative peoples. Yet they have been ignored and marginalised by the states that control their territory and the development agencies who are supposed to help them. This book argues that, while we should not ignore the profound difficulties of creating secure livelihoods in the Greater Horn of Africa, there is much to be learned from development successes, large and small. This book will be of great interest to students and scholars with an interest in development studies and human geography, with a particular emphasis on Africa. It will also appeal to development policy-makers and practitioners

    The cooperative movement in the Jaffna district of Sri Lanka from 1911 to 1970.

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    Using the problem analysis method advanced by Professor Brian Holmes, the study looks into the politico—economic and sociocultural factors that gave special significance to the Cooperative Movement in the Jaffna District of Sri Lanka when it was introduced nation—wide at the beginning of this century. With an intellectual tradition going back to at least five centuries and intensive educational activity by Christian missionaries since Portuguese times (1590), Jaffna enjoyed a lead over the rest of the country in the matter of educational provision and overall attainment. English education serving as a catalyst to raise the aspirations of the people, they naturally looked to new opportunities to better their economic prospects. The expanding public service, both in Ceylon as well as in Malaya and Singapore, opened new avenues of employment. The increasing demand for English education was met by a system of grant—aid to mission schools, which was exploited adequately by the people of Jaffna who were aware of the value of education, English education in particular, and were also amenable, by virtue of their socio—cultural orientation, to the new mores of English culture. The introduction of the Cooperative Credit Movement in 1911 came as a boon to the subsistence farmers of Jaffna who had been exploited for generations under traditional institutions. The cooperative credit societies, in addition to their contribution to the economic life of the community, also served as schools of democracy, as well as the training ground for leadership at the village level. l Under the leadership of the English educated, mainly teachers, lawyers and Malayan—returned pensioners, supervisory institutions were established at an early stage to foster the development of the Cooperative Movement, in particular the Jaffna Cooperative Provincial Bank (Secondary) and the Northern Division Cooperative Federation (Tertiary). While examining the conditions necessary for cooperative development, the study focuses on the policies of the Northern Cooperative Movement, including an evaluation of the educational policies and programmes of the Northern Division Cooperative Federation

    Constructing legitimacy?

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    How are agroecological transitions and rural development alternatives experienced by farmers and rural activists? To explore this broad issue, Claire Lagier examines how agroecology’s legitimacy is constructed and contested within the base membership and transnational networks of Brazil’s Landless Workers’ Movement (MST). The MST’s politics of land redistribution—as well as campaigning for sustainable rural livelihoods and education—have attracted significant attention worldwide, as have the food sovereignty alliance La Via Campesina’s agroecological training centres. However, few ethnographic studies have focused on the lived experiences of several generations of activists as they struggle to generate ecological transitions in the food system. Addressing this gap, Lagier’s study draws on intensive fieldwork carried out in Brazil in 2017–2018 alongside farmers living in a settlement affiliated with the MST, as well as young Latin American food sovereignty activists taking part in agroecological education. Claire Lagier defended her PhD thesis in Environmental Humanities at LMU Munich's Rachel Carson Center for Environment and Society in June 2019. Her doctoral work was funded by ENHANCE Marie-Curie ITN (2015-2018). She is currently based in Rio de Janeiro, Brazil
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