14,459 research outputs found
Quantum Algorithms for Boolean Equation Solving and Quantum Algebraic Attack on Cryptosystems
Decision of whether a Boolean equation system has a solution is an NPC
problem and finding a solution is NP hard. In this paper, we present a quantum
algorithm to decide whether a Boolean equation system FS has a solution and
compute one if FS does have solutions with any given success probability. The
runtime complexity of the algorithm is polynomial in the size of FS and the
condition number of FS. As a consequence, we give a polynomial-time quantum
algorithm for solving Boolean equation systems if their condition numbers are
small, say polynomial in the size of FS. We apply our quantum algorithm for
solving Boolean equations to the cryptanalysis of several important
cryptosystems: the stream cipher Trivum, the block cipher AES, the hash
function SHA-3/Keccak, and the multivariate public key cryptosystems, and show
that they are secure under quantum algebraic attack only if the condition
numbers of the corresponding equation systems are large. This leads to a new
criterion for designing cryptosystems that can against the attack of quantum
computers: their corresponding equation systems must have large condition
numbers
Is admiration a source of indeterminacy when the speed of habit formation is finite?
In an economy where the time preference rate is sufficiently decreasing in individual consumption, Chen and Hsu (2007) find that a consumption admiration effect can be a source of local indeterminacy, whereby average consumption flows exert a positive external effect on an individual's utility. In our paper, average consumption habits externally increase an individual's utility. The increase in average consumption habits is the difference between average consumption flows and existing average consumption habits adjusted for by the speed of the consumption habit formation. The model in Chen and Hsu (2007) is a special case that emerges only when the speed of habit formation is infinite. In our general model, an admiration effect is no longer a source of equilibrium indeterminacy unless the speed of consumption habit formation is infinite.Neoclassical growth model, consumption habit externalities, indeterminacy
From patterned response dependency to structured covariate dependency: categorical-pattern-matching
Data generated from a system of interest typically consists of measurements
from an ensemble of subjects across multiple response and covariate features,
and is naturally represented by one response-matrix against one
covariate-matrix. Likely each of these two matrices simultaneously embraces
heterogeneous data types: continuous, discrete and categorical. Here a matrix
is used as a practical platform to ideally keep hidden dependency among/between
subjects and features intact on its lattice. Response and covariate dependency
is individually computed and expressed through mutliscale blocks via a newly
developed computing paradigm named Data Mechanics. We propose a categorical
pattern matching approach to establish causal linkages in a form of information
flows from patterned response dependency to structured covariate dependency.
The strength of an information flow is evaluated by applying the combinatorial
information theory. This unified platform for system knowledge discovery is
illustrated through five data sets. In each illustrative case, an information
flow is demonstrated as an organization of discovered knowledge loci via
emergent visible and readable heterogeneity. This unified approach
fundamentally resolves many long standing issues, including statistical
modeling, multiple response, renormalization and feature selections, in data
analysis, but without involving man-made structures and distribution
assumptions. The results reported here enhance the idea that linking patterns
of response dependency to structures of covariate dependency is the true
philosophical foundation underlying data-driven computing and learning in
sciences.Comment: 32 pages, 10 figures, 3 box picture
The Minimal GUT with Inflaton and Dark Matter Unification
Giving up the solutions to the fine-tuning problems, we propose the
non-supersymmetric flipped model based on the minimal
particle content principle, which can be constructed from the four-dimensional
models, five-dimensional orbifold models, and local F-theory
models. To achieve gauge coupling unification, we introduce one pair
of vector-like fermions, which form complete
representation. Proton lifetime is around years, neutrino
masses and mixing can be explained via seesaw mechanism, baryon asymmetry can
be generated via leptogenesis, and vacuum stability problem can be solved as
well. In particular, we propose that inflaton and dark matter particle can be
unified to a real scalar field with symmetry, which is not an axion and
does not have the non-minimal coupling to gravity. Such kind of scenarios can
be applied to the generic scalar dark matter models. Also, we find that the
vector-like particle corrections to the masses can be about 6.6%, while
their corrections to the and masses are negligible.Comment: 5 pages, 4 figures;V2: published versio
Out-of-distribution forgetting: vulnerability of continual learning to intra-class distribution shift
Continual learning (CL) is an important technique to allow artificial neural
networks to work in open environments. CL enables a system to learn new tasks
without severe interference to its performance on old tasks, i.e., overcome the
problems of catastrophic forgetting. In joint learning, it is well known that
the out-of-distribution (OOD) problem caused by intentional attacks or
environmental perturbations will severely impair the ability of networks to
generalize. In this work, we reported a special form of catastrophic forgetting
raised by the OOD problem in continual learning settings, and we named it
out-of-distribution forgetting (OODF). In continual image classification tasks,
we found that for a given category, introducing an intra-class distribution
shift significantly impaired the recognition accuracy of CL methods for that
category during subsequent learning. Interestingly, this phenomenon is special
for CL as the same level of distribution shift had only negligible effects in
the joint learning scenario. We verified that CL methods without dedicating
subnetworks for individual tasks are all vulnerable to OODF. Moreover, OODF
does not depend on any specific way of shifting the distribution, suggesting it
is a risk for CL in a wide range of circumstances. Taken together, our work
identified an under-attended risk during CL, highlighting the importance of
developing approaches that can overcome OODF
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