Graffiti Networks: A Subversive, Internet-Scale File Sharing Model

The proliferation of peer-to-peer (P2P) file sharing protocols is due to their efficient and scalable methods for data dissemination to numerous users. But many of these networks have no provisions to provide users with long term access to files after the initial interest has diminished, nor are they able to guarantee protection for users from malicious clients that wish to implicate them in incriminating activities. As such, users may turn to supplementary measures for storing and transferring data in P2P systems. We present a new file sharing paradigm, called a Graffiti Network, which allows peers to harness the potentially unlimited storage of the Internet as a third-party intermediary. Our key contributions in this paper are (1) an overview of a distributed system based on this new threat model and (2) a measurement of its viability through a one-year deployment study using a popular web-publishing platform. The results of this experiment motivate a discussion about the challenges of mitigating this type of file sharing in a hostile network environment and how web site operators can protect their resources

Is Content Publishing in BitTorrent Altruistic or Profit-Driven

BitTorrent is the most popular P2P content delivery application where individual users share various type of content with tens of thousands of other users. The growing popularity of BitTorrent is primarily due to the availability of valuable content without any cost for the consumers. However, apart from required resources, publishing (sharing) valuable (and often copyrighted) content has serious legal implications for user who publish the material (or publishers). This raises a question that whether (at least major) content publishers behave in an altruistic fashion or have other incentives such as financial. In this study, we identify the content publishers of more than 55k torrents in 2 major BitTorrent portals and examine their behavior. We demonstrate that a small fraction of publishers are responsible for 66% of published content and 75% of the downloads. Our investigations reveal that these major publishers respond to two different profiles. On one hand, antipiracy agencies and malicious publishers publish a large amount of fake files to protect copyrighted content and spread malware respectively. On the other hand, content publishing in BitTorrent is largely driven by companies with financial incentive. Therefore, if these companies lose their interest or are unable to publish content, BitTorrent traffic/portals may disappear or at least their associated traffic will significantly reduce

Application of advanced technology to space automation

Automated operations in space provide the key to optimized mission design and data acquisition at minimum cost for the future. The results of this study strongly accentuate this statement and should provide further incentive for immediate development of specific automtion technology as defined herein. Essential automation technology requirements were identified for future programs. The study was undertaken to address the future role of automation in the space program, the potential benefits to be derived, and the technology efforts that should be directed toward obtaining these benefits

Intraplate deformation, stress in the lithosphere and the driving mechanism for plate motions

During this period work was carried out on three fronts relevant to the understanding of intraplate deformation, stress in the lithosphere, and the driving mechanisms for plate motions: (1) observational constraints, using GPS geodesy on the deformation in the region of the boundry between the Pacific and North American plates in central and southern California; (2) numerical modeling of the effects of temperature dependent lithospheric viscosity on the stress and strain history of extensional regimes; and (3) improvement of estimates of mantle viscosity variation, the long-wave-length density variations in the mantle, and the topography of the core-mantel boundary from modeling of geoid anomalies, nutation, and changes in length of day. These projects are described in more detail, followed by a discussion of meetings attended and a list of abstracts and papers submitted and/or published

Smartphone and Mobile Territories - Technical Knowledge Transformed into an Object Producing New Territorial Layers: An Experience in the City of Strasbourg

The “smartphone” is one of the individualized technical objects of the 21st century. This object is like a tool for socio-spatial reading of the territories thanks to the Internet of Things. The integration of geolocalised information with the Internet of Things opens the way to apprehend actual heritage of the cities in different ways. The relationship between digital and physical mobility in mapping physical territories in a sensitive way has been investigated only in a few studies and there is controversy about its predictors. Therefore we aimed to investigate the relationships between the invisible and non-visible elements of territories and users with their networks. We hypothesized that the circulations of 10 participants during 7 days in Strasbourg would enable us to trace a sample of images of the collective memory of the city relevant to its architecture and urbanity. The study is done by sending screenshots of the applications in use in the public space for at least three times in a day during a period of 1 week in the city of Strasbourg. The participants recorded also their daily journeys during this week via applications "Open GPS Tracker" or "Open GPX Tracker" (two open source applications). At the end of each day, they sent us both screenshots and open tracker gpx files of their journey and a total of 70 journeys were analysed. Afterwards the paths of the participants with their digital activities have been correlated by superimposing cartographically physical places frequented and digital activities carried out on each journey. By digital activities we considered all activities related to the use of smartphones, these activities may be related to the internet or not but they are categorically achievable through smartphones (messaging, communications applications, entertainment, etc.). We observed that the flow elements, such as public transport, constituted a good physical place where the diversity of digital activities was increased. Furthermore we saw that the nature of the subject's presence in the public space (rest, passage, movement via the different systems of transport, etc.) was associated with his/her digital movements. Moreover, some physical locations were more appropriate for digital activities than the others interestingly. Our work with a modest sample offered clues of the emergence of these new layers by the use of technological devices. Global computer knowledge is transformed into a mobile technical object and shared worldwide via smartphones. These objects are not just mere results of global knowledge, but they also produce socio-territorial knowledge by revealing the relations between the invisible or non-visible elements of territories and users. In other words, the people’s digital and physical mobility with new individualized objects forms new layers of territories that we name Mobile Territories. We found and illustrated with many attractive examples, for the first time, that the nature of the digital activities of the participants is shaped according to their physical location and own speed. And vice-versa, the physical location appeared to be augmented according to digital activities. By establishing connections between the digital activities and physical location, we understood that the both are moving in accordance with their relationships. Possible readings of the morphological and social characteristics of cities via layers of Mobile Territories, the consequences and the effects of these invisible layers would be remarkable for planners and architects

A review of microgrid development in the United States – A decade of progress on policies, demonstrations, controls, and software tools

Microgrids have become increasingly popular in the United States. Supported by favorable federal and local policies, microgrid projects can provide greater energy stability and resilience within a project site or community. This paper reviews major federal, state, and utility-level policies driving microgrid development in the United States. Representative U.S. demonstration projects are selected and their technical characteristics and non-technical features are introduced. The paper discusses trends in the technology development of microgrid systems as well as microgrid control methods and interactions within the electricity market. Software tools for microgrid design, planning, and performance analysis are illustrated with each tool's core capability. Finally, the paper summarizes the successes and lessons learned during the recent expansion of the U.S. microgrid industry that may serve as a reference for other countries developing their own microgrid industries