11 research outputs found

    Pairing computation on hyperelliptic curves of genus 2

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    Bilinear pairings have been recently used to construct cryptographic schemes with new and novel properties, the most celebrated example being the Identity Based Encryption scheme of Boneh and Franklin. As pairing computation is generally the most computationally intensive part of any painng-based cryptosystem, it is essential to investigate new ways in which to compute pairings efficiently. The vast majority of the literature on pairing computation focuscs solely on using elliptic curves. In this thesis we investigate pairing computation on supersingular hyperelliptic curves of genus 2 Our aim is to provide a practical alternative to using elliptic curves for pairing based cryptography. Specifically, we illustrate how to implement pairings efficiently using genus 2 curves, and how to attain performance comparable to using elliptic curves. We show that pairing computation on genus 2 curves over F2m can outperform elliptic curves by using a new variant of the Tate pairing, called the r¡j pairing, to compute the fastest pairing implementation in the literature to date We also show for the first time how the final exponentiation required to compute the Tate pairing can be avoided for certain hyperelliptic curves. We investigate pairing computation using genus 2 curves over large prime fields, and detail various techniques that lead to an efficient implementation, thus showing that these curves are a viable candidate for practical use

    Chemical dynamics using wavepacket methods

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    This thesis is concerned with studying chemical dynamics using time-dependent quantum mechanics and in particular using the Fourier method. Various ways of implementing the Fourier method are described, both for calculations in one dimension and for those in many dimensions. The Fourier method is then used to simulate time-resolved femtosecond and picosecond pump-probe experiments, which investigate the B state of the sodium trimer. The simulation is divided into three stages: the initial wavefunction is generated by modelling the effect of the pump laser pulse on the ground state wavefunction of the X state of the sodium trimer; the wavepacket now on the B state is propagated in time; the observables are extracted from the time-dependent wavefunction. The calculations are carried out initially in two dimensions, corresponding to the bending and asymmetric stretch normal modes, and then in three dimensions, i.e. including the symmetric stretch normal mode. The simulation of the time-resolved experiments produced physically plausible results. The correspondence with the experimental results was only fair, but this could be mostly accounted for by the poor quality of the potential energy surfaces used. Thus, even the relatively simple model used to simulate the time-resolved experiments is useful to gain both a qualitative explanation of the results of these experiments and an insight into the dynamics of systems which are in non-stationary states

    SCF-mediated degradation of the two translational regulators, CPB-3 and GLD-1, during oogenesis in C. elegans

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    The development of an organism and its adult homeostasis rely on regulatory mechanisms that control the underlying gene expression programs. In certain biological contexts, such as germ cell development, gene expression regulation is largely executed at the post-­‐transcriptional level. This relies on RNA-­‐binding proteins (RBPs), whose activity and expression are also heavily controlled. While the RNA-­‐binding potential of RBPs is currently of intense scrutiny, surprisingly little is known to date about the molecular mechanisms that control RNA-­‐binding proteins abundance in the context of germ cell development. This work identifies the molecular mechanisms that shape expression patterns of two evolutionarily conserved RNA-­‐binding proteins, CPB-­‐3 and GLD-­‐ 1, which belong to CPEB and STAR protein family, respectively. By focusing on their regulation in the C. elegans germ line, this work reveals an involvement of the proteasome in reducing levels of CPB-­‐3/CPEB and GLD-­‐1/STAR at the pachytene-­‐to-­‐diplotene transition during meiotic prophase I. Furthermore, it documents that CPB-­‐3 and GLD-­‐1 are targeted to proteasomal degradation by a conserved SCF ubiquitin ligase complex that utilises SEL-­‐10/Fbxw7 as a substrate recognition subunit. Importantly, destabilisation of both RBPs is likely triggered by their phosphorylation, which is regulated by the mitogen-­‐activated protein kinase, MPK-­‐1, and restricted to the meiotic timepoint of pachytene exit. Lastly, this work investigates the potential consequences of target mRNA regulation upon delayed RBP degradation. Altogether, the collected data characterise a molecular pathway of CPEB and STAR protein turnover, and suggest that MPK-­‐1 signaling may couple RBP-­‐mediated regulation of gene expression to progression through meiosis during oogenesis

    Applications of hybrid and digital computation methods in aerospace-related sciences and engineering

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    The computing equipment in the engineering systems simulation laboratory of the Houston University Cullen College of Engineering is described and its advantages are summarized. The application of computer techniques in aerospace-related research psychology and in chemical, civil, electrical, industrial, and mechanical engineering is described in abstracts of 84 individual projects and in reprints of published reports. Research supports programs in acoustics, energy technology, systems engineering, and environment management as well as aerospace engineering

    Annual Report of the University, 1970-1971, Volumes 1-3

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    Reports to the President

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    A compilation of annual reports for the 1999-2000 academic year, including a report from the President of the Massachusetts Institute of Technology, as well as reports from the academic and administrative units of the Institute. The reports outline the year's goals, accomplishments, honors and awards, and future plans

    Earth resources: A continuing bibliography, issue 46

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    This bibliography lists 467 reports, articles and other documents introdcued into the NASA scientific and technical information system between April 1 and June 30, 1985. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental cultural resources geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economical analysis

    Bibliography of Lewis Research Center technical publications announced in 1986

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    This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1986. All the publications were announced in the 1986 issues of Scientific and Technical Aerospace Reports (STAR) and/or International Aerospace Abstracts (IAA). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

    Development of an eclectic dictionary for court reporting

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    The purpose of this research was to evaluate the resources available to the field of court reporting in the United States, specifically, the existence of an eclectic dictionary which encompasses all known methodologies and advanced principles; This study reviewed articles, texts, and manuals pertaining to court reporting to ascertain the need for an eclectic dictionary; A questionnaire was prepared and sent to all court reporting program directors of accredited programs in the United States. They were asked to provide their overall philosophy in terms of developing an eclectic dictionary and requested to respond about the need for such a dictionary; From the responses to the survey, an eclectic dictionary was created and included and appended to the study
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