174 research outputs found
QR code based authentication method for IoT applications using three security layers
A quick response code-based authentication method (QRAM) is proposed. QRAM is applicable for lots of internet of things (IoT) applications. QRAM aims to verify requests of such an access to IoT applications. Requests are made using a quick response code (QRC). To authenticate contents of QRC, users will scan QRC to access IoT applications. To authenticate contents of QRC, three procedures are applied. QRAM contributes to IoT automatic access systems or smart applications in terms of authentication and safety of access. QRAM is evaluated in term of security factors (e.g., authentication). Computation time of authentication procedures for several IoT applications has become a considerable issue. QRAM aims to reduce computation time consumed to authenticate each QRC. Some authentication techniques still face difficulties when an IoT application requires fast response to users; therefore, QRAM aims to enhance so to meet real-time applications. Thus, QRAM is compared to several competitive methods used to verify QRC in term of computation time. Results confirmed that QRAM is faster than other competitive techniques. Besides, results have shown a high level of complexity in term of decryption time needed to deduce private contents of QRC. QRAM also is robust against unauthorized requests of access
Development of a fuzzy qualitative risk assessment model applied to construction industry
Dissertação para obtenção do Grau de Doutor em
Engenharia IndustrialThe construction industry is plagued by occupational risky situations and poor working conditions. Risk Assessment for Occupational Safety (RAOS) is the first and key step to achieve adequate safety levels, particularly to support decision-making in safety programs.
Most construction safety efforts are applied informally under the premise that simply allocating more resources to safety management will improve safety on site. Moreover, there are many traditional methods to address RAOS, but few have been adapted and validated for use in the construction industry, thus producing poor results.
The contribution of this dissertation is a qualitative fuzzy RAOS model, tailored for the construction industry, named QRAM (Qualitative Risk Assessment Model). QRAM is based on four dimensions: Safety Climate Adequacy, (work accidents) Severity Factors, (work accidents) Possibility Factors and Safety Barriers Effectiveness.
The risk assessment is based on real data collected by observation of reality, interviews with workers, foreman and engineers and consultation of site documents (working procedures, reports of work accident investigation, etc.), avoiding the use of data obtained by statistical tecnhiques.
To rating each parameter it was defined qualitative evaluators - linguistic variables - which allow to perform a user-friendly knowledge elicitation.
QRAM was, firstly evaluated by “peer” review, with 12 safety experts from Brazil (2), Bulgaria (1), Greece (3), Turkey (3) and Portugal (3), and then, evaluated by comparing QRAM with other RAOS tecnhiques and methods.
The safety experts , concluded that: a) QRAM is a versatile tool for occupational safety risk assessment on construction sites; b) the specific checklists for knowledge elicitation are a good decision aid and, c) the use of linguistic variables is a better way to make the risk assessments process more objective and reliable.Fundação para a Ciência e Tecnologia - PhD Scholarship SFRH/BD/39610/200
Design of the control logic for StarT-Voyager
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 61).by Daniel L. Rosenband.M.Eng
The prospects of quantum computing in computational molecular biology
Quantum computers can in principle solve certain problems exponentially more
quickly than their classical counterparts. We have not yet reached the advent
of useful quantum computation, but when we do, it will affect nearly all
scientific disciplines. In this review, we examine how current quantum
algorithms could revolutionize computational biology and bioinformatics. There
are potential benefits across the entire field, from the ability to process
vast amounts of information and run machine learning algorithms far more
efficiently, to algorithms for quantum simulation that are poised to improve
computational calculations in drug discovery, to quantum algorithms for
optimization that may advance fields from protein structure prediction to
network analysis. However, these exciting prospects are susceptible to "hype",
and it is also important to recognize the caveats and challenges in this new
technology. Our aim is to introduce the promise and limitations of emerging
quantum computing technologies in the areas of computational molecular biology
and bioinformatics.Comment: 23 pages, 3 figure
A quantum active learning algorithm for sampling against adversarial attacks
Adversarial attacks represent a serious menace for learning algorithms and
may compromise the security of future autonomous systems. A theorem by Khoury
and Hadfield-Menell (KH), provides sufficient conditions to guarantee the
robustness of machine learning algorithms, but comes with a caveat: it is
crucial to know the smallest distance among the classes of the corresponding
classification problem. We propose a theoretical framework that allows us to
think of active learning as sampling the most promising new points to be
classified, so that the minimum distance between classes can be found and the
theorem KH used. Additionally, we introduce a quantum active learning algorithm
that makes use of such framework and whose complexity is polylogarithmic in the
dimension of the space, , and the size of the initial training data ,
provided the use of qRAMs; and polynomial in the precision, achieving an
exponential speedup over the equivalent classical algorithm in and .
This algorithm may be nevertheless `dequantized' reducing the advantage to
polynomial.Comment: Contains an additional dequantization appendix E that does not appear
in the published versio
Implementation of the Density-functional Theory on Quantum Computers with Linear Scaling with respect to the Number of Atoms
Density-functional theory (DFT) has revolutionized computer simulations in
chemistry and material science. A faithful implementation of the theory
requires self-consistent calculations. However, this effort involves repeatedly
diagonalizing the Hamiltonian, for which a classical algorithm typically
requires a computational complexity that scales cubically with respect to the
number of electrons. This limits DFT's applicability to large-scale problems
with complex chemical environments and microstructures. This article presents a
quantum algorithm that has a linear scaling with respect to the number of
atoms, which is much smaller than the number of electrons. Our algorithm
leverages the quantum singular value transformation (QSVT) to generate a
quantum circuit to encode the density-matrix, and an estimation method for
computing the output electron density. In addition, we present a randomized
block coordinate fixed-point method to accelerate the self-consistent field
calculations by reducing the number of components of the electron density that
needs to be estimated.
The proposed framework is accompanied by a rigorous error analysis that
quantifies the function approximation error, the statistical fluctuation, and
the iteration complexity. In particular, the analysis of our self-consistent
iterations takes into account the measurement noise from the quantum circuit.
These advancements offer a promising avenue for tackling large-scale DFT
problems, enabling simulations of complex systems that were previously
computationally infeasible
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