10,403 research outputs found
Collaborative similarity analysis of multilayer developer-project bipartite network
To understand the multiple relations between developers and projects on
GitHub as a whole, we model them as a multilayer bipartite network and analyze
the degree distributions, the nearest neighbors' degree distributions and their
correlations with degree, and the collaborative similarity distributions and
their correlations with degree. Our results show that all degree distributions
have a power-law form, especially, the degree distribution of projects in
watching layer has double power-law form. Negative correlations between nearest
neighbors' degree and degree for both developers and projects are observed in
both layers, exhibiting a disassortative mixing pattern. The collaborative
similarity of both developers and projects negatively correlates with degree in
watching layer, while a positive correlations is observed for developers in
forking layer and no obvious correlation is observed for projects in forking
layer
Formal Consistency Checking over Specifications in Natural Languages
Early stages of system development involve outlining desired features such as
functionality, availability, or usability. Specifications are derived from
these features that concretize vague ideas presented in natural languages. The
challenge for the validation of specifications arises from the syntax and
semantic gap between different representations and the need of automatic tools.
In this paper, we present a requirement-consistency maintenance framework to
produce consistent representations. The first part is the automatic translation
from natural languages describing functionalities to formal logic with an
abstraction of time. It extends pure syntactic parsing by adding semantic
reasoning and the support of partitioning input and output variables. The
second part is the use of synthesis techniques to examine if the requirements
are consistent in terms of realizability. When the process fails, the formulas
that cause the inconsistency are reported to locate the problem.Comment: 8 pages, 2 figure
Testing Autonomous Systems with Believed Equivalence Refinement
Continuous engineering of autonomous driving functions commonly requires
deploying vehicles in road testing to obtain inputs that cause problematic
decisions. Although the discovery leads to producing an improved system, it
also challenges the foundation of testing using equivalence classes and the
associated relative test coverage criterion. In this paper, we propose believed
equivalence, where the establishment of an equivalence class is initially based
on expert belief and is subject to a set of available test cases having a
consistent valuation. Upon a newly encountered test case that breaks the
consistency, one may need to refine the established categorization in order to
split the originally believed equivalence into two. Finally, we focus on
modules implemented using deep neural networks where every category partitions
an input over the real domain. We establish new equivalence classes by guiding
the new test cases following directions suggested by its k-nearest neighbors,
complemented by local robustness testing. The concept is demonstrated in a
lane-keeping assist module indicating the potential of our proposed approach
Accelerating adiabatic quantum transfer for three-level -type structure systems via picture transformation
In this paper, we investigate the quantum transfer for the system with
three-level -type structure, and construct a shortcut to the adiabatic
passage via picture transformation to speed up the evolution. We can design the
pulses directly without any additional couplings. Moreover, by choosing
suitable control parameters, the Rabi frequencies of pulses can be expressed by
the linear superpositions of Gaussian functions, which could be easily realized
in experiments. Compared with the previous works using the stimulated Raman
adiabatic passage, the quantum transfer can be significantly accelerated with
the present scheme.Comment: 16 pages, 5 figures, has been accepted by Annals of Physic
Optimal shortcut approach based on an easily obtained intermediate Hamiltonian
We present a general approach to speed up the adiabatic process without
adding the traditional counterdiabatic driving (CD) Hamiltonian. The strategy
is to design an easy-to-get intermediate Hamiltonian to connect the original
Hamiltonian and final transitionless Hamiltonian. With final transitionless
Hamiltonian, the same target can be achieved as in the adiabatic process
governed by the original Hamiltonian, but in a shorter time. We apply the
present approach to a three-level system, and the result shows that the final
transitionless Hamiltonian usually has the same structure as the original
Hamiltonian but with different time-dependent coefficients, allowing speedup to
be achieved in a much easier way compared to previous methods.Comment: 12 pages,8 figures, has been accepted for publication as a Regular
Article in Physical Review
Coherent control in quantum open systems: An approach for accelerating dissipation-based quantum state generation
In this paper, we propose an approach to accelerate the dissipation dynamics
for quantum state generation with Lyapunov control. The strategy is to add
target-state-related coherent control fields into the dissipation process to
intuitively improve the evolution speed. By applying the current approach,
without losing the advantages of dissipation dynamics, the target stationary
states can be generated in a much shorter time as compared to that via
traditional dissipation dynamics. As a result, the current approach containing
the advantages of coherent unitary dynamics and dissipation dynamics allows for
significant improvement in quantum state generation.Comment: 5 pages, 6 figures, has been accepted as a regular article in
Physical Review A and revised according to some suggestion
Distributed Priority Synthesis and its Applications
Given a set of interacting components with non-deterministic variable update
and given safety requirements, the goal of priority synthesis is to restrict,
by means of priorities, the set of possible interactions in such a way as to
guarantee the given safety conditions for all possible runs. In distributed
priority synthesis we are interested in obtaining local sets of priorities,
which are deployed in terms of local component controllers sharing intended
next moves between components in local neighborhoods only. These possible
communication paths between local controllers are specified by means of a
communication architecture. We formally define the problem of distributed
priority synthesis in terms of a multi-player safety game between players for
(angelically) selecting the next transition of the components and an
environment for (demonically) updating uncontrollable variables; this problem
is NP-complete. We propose several optimizations including a solution-space
exploration based on a diagnosis method using a nested extension of the usual
attractor computation in games together with a reduction to corresponding SAT
problems. When diagnosis fails, the method proposes potential candidates to
guide the exploration. These optimized algorithms for solving distributed
priority synthesis problems have been integrated into our VissBIP framework. An
experimental validation of this implementation is performed using a range of
case studies including scheduling in multicore processors and modular robotics.Comment: 1. Timestamp the joint work "Distributed Priority Synthesis" from
four institutes (Verimag, TUM, ISCAS, fortiss). 2. This version (v.2) updates
related work in distributed synthesi
Arbitrary quantum state engineering in three-state systems via Counterdiabatic driving
A scheme for arbitrary quantum state engineering (QSE) in three-state systems
is proposed. Firstly, starting from a set of complete orthogonal time-dependent
basis with undetermined coefficients, a time-dependent Hamiltonian is derived
via Counterdiabatic driving for the purpose of guiding the system to attain an
arbitrary target state at a predefined time. Then, on request of the assumed
target states, two single-mode driving protocols and a multi-mode driving
protocol are proposed as examples to discuss the validity of the QSE scheme.
The result of comparison between single-mode driving and multi-mode driving
shows that multi-mode driving seems to have a wider rang of application
prospect because it can drive the system to an arbitrary target state from an
arbitrary initial state also at a predefined time even without the use of
microwave fields for the transition between the two ground states. Moreover,
for the purpose of discussion in the scheme's feasibility in practice, a
polynomial ansatz as the simplest exampleis used to fix the pulses. The result
shows that the pulses designed to implement the protocols are not hard to be
realized in practice. At the end, QSE in higher-dimensional systems is also
discussed in brief as a generalization example of the scheme.Comment: 16 pages, 13 figures, has been accepted by Scientific Report
Method for constructing shortcuts to adiabaticity by a substitute of counterdiabatic driving terms
We propose an efficientmethod to construct shortcuts to adiabaticity through
designing a substitute Hamiltonian to try to avoid the defect in which the
speed-up protocol' Hamiltonian may involve terms which are difficult to realize
in practice. We show that as long as the counterdiabatic coupling terms-even
only some of them-have been nullified by the additional Hamiltonian, the
corresponding shortcuts to the adiabatic process could be constructed and the
adiabatic process would be sped up. As an application example, we apply this
method to the popular Landau-Zener model for the realization of fast population
inversion. The results show that in both Hermitian and non-Hermitian systems,
we can design different additional Hamiltonians to replace the traditional
counterdiabatic driving Hamiltonian to speed up the process. This method
provides many choices for designing additional terms of the Hamiltonian such
that one can choose a realizable model in practice.Comment: 11pages, 6 figures, has been accepted for publication as a Regular
Article in Physicial Review
Architecting Dependable Learning-enabled Autonomous Systems: A Survey
We provide a summary over architectural approaches that can be used to
construct dependable learning-enabled autonomous systems, with a focus on
automated driving. We consider three technology pillars for architecting
dependable autonomy, namely diverse redundancy, information fusion, and runtime
monitoring. For learning-enabled components, we additionally summarize recent
architectural approaches to increase the dependability beyond standard
convolutional neural networks. We conclude the study with a list of promising
research directions addressing the challenges of existing approaches
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