1,121 research outputs found

    Malleable Coding with Fixed Reuse

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    In cloud computing, storage area networks, remote backup storage, and similar settings, stored data is modified with updates from new versions. Representing information and modifying the representation are both expensive. Therefore it is desirable for the data to not only be compressed but to also be easily modified during updates. A malleable coding scheme considers both compression efficiency and ease of alteration, promoting codeword reuse. We examine the trade-off between compression efficiency and malleability cost-the difficulty of synchronizing compressed versions-measured as the length of a reused prefix portion. Through a coding theorem, the region of achievable rates and malleability is expressed as a single-letter optimization. Relationships to common information problems are also described

    Malleable coding for updatable cloud caching

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    In software-as-a-service applications provisioned through cloud computing, locally cached data are often modified with updates from new versions. In some cases, with each edit, one may want to preserve both the original and new versions. In this paper, we focus on cases in which only the latest version must be preserved. Furthermore, it is desirable for the data to not only be compressed but to also be easily modified during updates, since representing information and modifying the representation both incur cost. We examine whether it is possible to have both compression efficiency and ease of alteration, in order to promote codeword reuse. In other words, we study the feasibility of a malleable and efficient coding scheme. The tradeoff between compression efficiency and malleability cost-the difficulty of synchronizing compressed versions-is measured as the length of a reused prefix portion. The region of achievable rates and malleability is found. Drawing from prior work on common information problems, we show that efficient data compression may not be the best engineering design principle when storing software-as-a-service data. In the general case, goals of efficiency and malleability are fundamentally in conflict.This work was supported in part by an NSF Graduate Research Fellowship (LRV), Grant CCR-0325774, and Grant CCF-0729069. This work was presented at the 2011 IEEE International Symposium on Information Theory [1] and the 2014 IEEE International Conference on Cloud Engineering [2]. The associate editor coordinating the review of this paper and approving it for publication was R. Thobaben. (CCR-0325774 - NSF Graduate Research Fellowship; CCF-0729069 - NSF Graduate Research Fellowship)Accepted manuscrip

    Gene alterations at Drosophila inversion breakpoints provide prima facie evidence for natural selection as an explanation for rapid chromosomal evolution

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    <p>Abstract</p> <p>Background</p> <p>Chromosomal inversions have been pervasive during the evolution of the genus Drosophila, but there is significant variation between lineages in the rate of rearrangement fixation. <it>D. mojavensis</it>, an ecological specialist adapted to a cactophilic niche under extreme desert conditions, is a chromosomally derived species with ten fixed inversions, five of them not present in any other species.</p> <p>Results</p> <p>In order to explore the causes of the rapid chromosomal evolution in <it>D. mojavensis</it>, we identified and characterized all breakpoints of seven inversions fixed in chromosome 2, the most dynamic one. One of the inversions presents unequivocal evidence for its generation by ectopic recombination between transposon copies and another two harbor inverted duplications of non-repetitive DNA at the two breakpoints and were likely generated by staggered single-strand breaks and repair by non-homologous end joining. Four out of 14 breakpoints lay in the intergenic region between preexisting duplicated genes, suggesting an adaptive advantage of separating previously tightly linked duplicates. Four out of 14 breakpoints are associated with transposed genes, suggesting these breakpoints are fragile regions. Finally two inversions contain novel genes at their breakpoints and another three show alterations of genes at breakpoints with potential adaptive significance.</p> <p>Conclusions</p> <p><it>D. mojavensis </it>chromosomal inversions were generated by multiple mechanisms, an observation that does not provide support for increased mutation rate as explanation for rapid chromosomal evolution. On the other hand, we have found a number of gene alterations at the breakpoints with putative adaptive consequences that directly point to natural selection as the cause of <it>D. mojavensis </it>rapid chromosomal evolution.</p

    Digital Image Access & Retrieval

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    The 33th Annual Clinic on Library Applications of Data Processing, held at the University of Illinois at Urbana-Champaign in March of 1996, addressed the theme of "Digital Image Access & Retrieval." The papers from this conference cover a wide range of topics concerning digital imaging technology for visual resource collections. Papers covered three general areas: (1) systems, planning, and implementation; (2) automatic and semi-automatic indexing; and (3) preservation with the bulk of the conference focusing on indexing and retrieval.published or submitted for publicatio

    From holism to compositionality: memes and the evolution of segmentation, syntax, and signification in music and language

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    Steven Mithen argues that language evolved from an antecedent he terms “Hmmmmm, [meaning it was] Holistic, manipulative, multi-modal, musical and mimetic”. Owing to certain innate and learned factors, a capacity for segmentation and cross-stream mapping in early Homo sapiens broke the continuous line of Hmmmmm, creating discrete replicated units which, with the initial support of Hmmmmm, eventually became the semantically freighted words of modern language. That which remained after what was a bifurcation of Hmmmmm arguably survived as music, existing as a sound stream segmented into discrete units, although one without the explicit and relatively fixed semantic content of language. All three types of utterance – the parent Hmmmmm, language, and music – are amenable to a memetic interpretation which applies Universal Darwinism to what are understood as language and musical memes. On the basis of Peter Carruthers’ distinction between ‘cognitivism’ and ‘communicativism’ in language, and William Calvin’s theories of cortical information encoding, a framework is hypothesized for the semantic and syntactic associations between, on the one hand, the sonic patterns of language memes (‘lexemes’) and of musical memes (‘musemes’) and, on the other hand, ‘mentalese’ conceptual structures, in Chomsky’s ‘Logical Form’ (LF)

    The Piratical Ethos: Textual Activity and Intellectual Property in Digital Environments

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    The Piratical Ethos: Textual Activity and Intellectual Property in Digital Environments examines the definition, function, and application of intellectual property in contexts of electronically mediated social production. With a focus on immaterial production - or the forms of coordinated social activity employed to produce knowledge and information in the networked information economy - this project ultimately aims to demonstrate how current intellectual property paradigms must be rearticulated for an age of digital (re)production. By considering the themes of Piracy , Intellectual Property , and Distributed Social Production this dissertation provides an overview of the current state of peer production and intellectual property in the Humanities and Writing Studies. Next, this project develops and implements a communicational-mediational research methodology to theorize how both discursive and material data lend themselves to a more nuanced understanding of the ways that technologies of communication and coordination effect attitudes toward intellectual property. After establishing both a methodology and an interdisciplinary grounding for the themes of the work, this dissertation presents a grounded theoretic analysis of piratical discourse to reveal what I call the piratical ethos , or the guiding attitudes of individuals actively contesting intellectual property in piratical acts of distributed social production. Congruently, this work also investigates the material dynamics of piratical activity by analyzing the cultural-historical activity systems wherein piratical subjectivity emerges, emphasizing the agenic capacity of interfacial technologies at the scales of user and system. Exploring the attitudes of piratical subjects and the technological genres that mediate piratical activity, I contend that the conclusions drawn from The Piratical Ethos can assist Writing Studies researchers with developing novel methodologies to study the intersections of intellectual property and distributed social production in digital worlds

    User-Driven Change enabled by Malleable Information Technology

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    Malleable technologies promise almost infinite applications for organizations. Users can utilize the generic functionalities of such technologies to support personal tasks or combine and adapt them to create custom artefacts and, hence, shape organizational routines. Although users have a crucial part in the transition from generic potentials to effective use of malleable technologies, we know little about processes and factors that facilitate users in this endeavor and how created artefacts evolve over time. This dissertation presents three studies, which target these research gaps. The studies draw on affordance theory, cognitive load theory, routine theory and momentum of change and apply qualitative and quantitative methods to the case of a malleable technology implementation project in an organization. The results suggest that users perceive and actualize afforded potentials of malleable technologies through different processes, which depend on user characteristics and local environmental factors. Moreover, the longitudinal observations show that users often perform a series of changes, when they form custom artefacts from malleable technologies. The intensity of these changes can be described as momentum that depends on factors like the existing artefact or the embeddedness of the related routine. Overall, the dissertation findings open the black box of user-driven change under malleable technology and help to explain variations in the created momentum of change

    Totalizing institutions, critique and resistance

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    Drawing on Deleuze’s ‘Postscript on Control Societies’, our initial focus in this article will be on the role of institutions within societies of control, an analysis which brings Deleuze into the orbit of Ervin Goffman’s famous ethnographic work on total institutions. This cross-comparative analysis of Deleuze and Goffman (also montaged with Foucault’s important work on disciplinary institutions) will allow us to show how institutions of control function by sequencing dividuals across institutional domains in a continual process of totalization. Inspired by James Williams’s recent work on the ‘process philosophy of signs’, we then argue that a critique of totalizing institutions can be positively articulated as a process oriented challenge to algorithmic technologies and as a counter-sequencing of institutional control. We conclude with some reflections upon the emergent modes of resistance that challenge both institutional and technological control and we will proffer criteria for assessing such practices in relation to the two-sided nature of critique they enact, both processual and counter-sequential
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