797,373 research outputs found
Virtual Site as an aid to first-year learning
Courses run by the School of the Built Environment have a range of entry requirements that enable diverse students and those with lower academic qualifications to gain entry. This results in a particular challenge for the Documentation & Estimating module, which is a very practical, skillsand competence-based module. It is delivered to large tutorial cohorts of mixed courses, abilities, ages and experience. Many students need one-toone guidance to understand what, practically, they have to do. They are given the theory first in a lecture and then have practical tutorials to carry out assessed exercises with limited tutor contact time. The module includes some basic surveying techniques and a levelling exercise which involves the transfer of a level from an assumed benchmark to establish a temporary benchmark some distance away. Many students have problems with computation of results. In spite of a careful introduction and explanation of the use of the instruments and techniques, many students find it difficult to visualise what is happening
Fast formulas for computing cryptographic pairings
The most powerful known primitive in public-key cryptography is undoubtedly elliptic curve pairings. Upon their introduction just over ten years ago the computation of pairings was far too slow for them to be considered a practical option.
This resulted in a vast amount of research from many mathematicians and computer scientists around the globe aiming to improve this computation speed. From the use of modern results in algebraic and arithmetic geometry to the application of foundational number theory that dates back to the days of Gauss and Euler, cryptographic pairings have since experienced a great deal of improvement. As a result, what was an extremely expensive computation that took several minutes is now a high-speed operation that takes less than a millisecond.
This thesis presents a range of optimisations to the state-of-the-art in cryptographic pairing computation. Both through extending prior techniques, and introducing several novel ideas of our own, our work has contributed to recordbreaking pairing implementations
A FPGA system for QRS complex detection based on Integer Wavelet Transform
Due to complexity of their mathematical computation, many QRS detectors are implemented in software and cannot operate in real time. The paper presents a real-time hardware based solution for this task. To filter ECG signal and to extract QRS complex it employs the Integer Wavelet Transform. The system includes several components and is incorporated in a single FPGA chip what makes it suitable for direct embedding in medical instruments or wearable health care devices. It has sufficient accuracy (about 95%), showing remarkable noise immunity and low cost. Additionally, each system component is composed of several identical blocks/cells what makes the design highly generic. The capacity of today existing FPGAs allows even dozens of detectors to be placed in a single chip. After the theoretical introduction of wavelets and the review of their application in QRS detection, it will be shown how some basic wavelets can be optimized for easy hardware implementation. For this purpose the migration to the integer arithmetic and additional simplifications in calculations has to be done. Further, the system architecture will be presented with the demonstrations in both, software simulation and real testing. At the end, the working performances and preliminary results will be outlined and discussed. The same principle can be applied with other signals where the hardware implementation of wavelet transform can be of benefit
The Brown-York mass of black holes in Warped Anti-de Sitter space
We give a direct computation of the mass of black holes in Warped Anti-de
Sitter space (WAdS) in terms of the Brown-York stress-tensor at the boundary.
This permits to explore to what extent the holographic renormalization
techniques can be applied to such type of deformation of AdS. We show that,
despite some components of the boundary stress-tensor diverge and resist to be
regularized by the introduction of local counterterms, the precise combination
that gives the quasilocal energy density yields a finite integral. The result
turns out to be in agreement with previous computations of the black hole mass
obtained with different approaches. This is seen to happen both in the case of
Topologically Massive Gravity and of the so-called New Massive Gravity. Here,
we focus our attention on the latter. We observe that, despite other conserved
charges diverge in the near boundary limit, the finite part in the large radius
expansion captures the physically relevant contribution. We compute the black
hole angular momentum in this way and we obtain a result that is in perfect
agreement with previous calculations.Comment: 8 pages. v2 discussion and appendix added, references added. To
appear in JHE
Relational Expressions for Data Transformation and Computation
Separate programming models for data transformation (declarative) and
computation (procedural) impact programmer ergonomics, code reusability and
database efficiency. To eliminate the necessity for two models or paradigms, we
propose a small but high-leverage innovation: the introduction of complete
relations into the relational database. Complete relations and the discipline
of constraint programming, which concerns them, are founded on the same algebra
as relational databases. We claim that by synthesising the relational database
of Codd and Date, with the results of the constraint programming community, the
relational model holistically offers programmers a single declarative paradigm
for both data transformation and computation, reusable code with computations
that are indifferent to what is input and what is output, and efficient
applications with the query engine optimising and parallelising all levels of
data transformation and computation.Comment: 12 pages, 4 tables. To be published in the proceedings of the
Shepherding Track of the 2023 Australasian Database Conference Melbourne (Nov
1-3
Optimization of supply diversity for the self-assembly of simple objects in two and three dimensions
The field of algorithmic self-assembly is concerned with the design and
analysis of self-assembly systems from a computational perspective, that is,
from the perspective of mathematical problems whose study may give insight into
the natural processes through which elementary objects self-assemble into more
complex ones. One of the main problems of algorithmic self-assembly is the
minimum tile set problem (MTSP), which asks for a collection of types of
elementary objects (called tiles) to be found for the self-assembly of an
object having a pre-established shape. Such a collection is to be as concise as
possible, thus minimizing supply diversity, while satisfying a set of stringent
constraints having to do with the termination and other properties of the
self-assembly process from its tile types. We present a study of what we think
is the first practical approach to MTSP. Our study starts with the introduction
of an evolutionary heuristic to tackle MTSP and includes results from extensive
experimentation with the heuristic on the self-assembly of simple objects in
two and three dimensions. The heuristic we introduce combines classic elements
from the field of evolutionary computation with a problem-specific variant of
Pareto dominance into a multi-objective approach to MTSP.Comment: Minor typos correcte
A supersymmetric exotic field theory in (1+1) dimensions. One loop soliton quantum mass corrections
We consider one loop quantum corrections to soliton mass for the
supersymmetric extension of the (1+1)-dimensional scalar field theory with the
potential . First, we compute
the one loop quantum soliton mass correction of the bosonic sector. To do that,
we regularize implicitly such quantity by subtracting and adding its
corresponding tadpole graph contribution, and use the renormalization
prescription that the added term vanishes with the corresponding counterterms.
As a result we get a finite unambiguous formula for the soliton quantum mass
corrections up to one loop order. Afterwards, the computation for the
supersymmetric case is extended straightforwardly and we obtain for the one
loop quantum correction of the SUSY kink mass the expected value previously
derived for the SUSY sine-Gordon and models. However, we also have
found that for a particular value of the parameters, contrary to what was
expected, the introduction of supersymmetry in this model worsens ultraviolet
divergences rather than improving them.Comment: 16 pages, 8 figures; Major modifications included to match version
published in JHE
Output privacy in secure multiparty computation
Abstract. In secure multiparty computation, a set of mutually mistrusting players engage in a protocol to compute an arbitrary, publicly known polynomial-sized function of the party’s private inputs, in a way that does not reveal (to an adversary controlling some of the players) any knowledge about the remaining inputs, beyond what can be deduced from the obtained output(s). Since its introduction by Yao [39], and Goldreich, Micali and Wigderson [29], this powerful paradigm has received a lot of attention. All throughout, however, very little attention has been given to the privacy of the players ’ outputs. Yet, disclosure of (part of) the output(s) may have serious consequences for the overall security of the application e.g., when the computed output is a secret key; or when the evaluation of the function is part of a larger computation, so that the function’s output(s) will be used as input(s) in the next phase. In this work, we define the notion of private-output multiparty computation. This newly revised notion encompasses (as a particular case) the classical definition and allows a set of players to jointly compute the output of a common function in such a way that the execution of the protocol reveals no information (to an adversary controlling some of the players) about (some part of) the outputs (other than what follows from the description of the function itself). Next, we formall
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