242,377 research outputs found
Dynamic Protocol Reverse Engineering a Grammatical Inference Approach
Round trip engineering of software from source code and reverse engineering of software from binary files have both been extensively studied and the state-of-practice have documented tools and techniques. Forward engineering of protocols has also been extensively studied and there are firmly established techniques for generating correct protocols. While observation of protocol behavior for performance testing has been studied and techniques established, reverse engineering of protocol control flow from observations of protocol behavior has not received the same level of attention. State-of-practice in reverse engineering the control flow of computer network protocols is comprised of mostly ad hoc approaches. We examine state-of-practice tools and techniques used in three open source projects: Pidgin, Samba, and rdesktop . We examine techniques proposed by computational learning researchers for grammatical inference. We propose to extend the state-of-art by inferring protocol control flow using grammatical inference inspired techniques to reverse engineer automata representations from captured data flows. We present evidence that grammatical inference is applicable to the problem domain under consideration
Remote Macroscopic Entanglement on a Photonic Crystal Architecture
The outstanding progress in nanostructure fabrication and cooling
technologies allows what was unthinkable a few decades ago: bringing
single-mode mechanical vibrations to the quantum regime. The coupling between
photon and phonon excitations is a natural source of nonclassical states of
light and mechanical vibrations, and its study within the field of cavity
optomechanics is developing lightning-fast. Photonic crystal cavities are
highly integrable architectures that have demonstrated the strongest
optomechanical coupling to date, and should therefore play a central role for
such hybrid quantum state engineering. In this context, we propose a realistic
heralding protocol for the on-chip preparation of remotely entangled mechanical
states, relying on the state-of-the-art optomechanical parameters of a
silicon-based nanobeam structure. Pulsed sideband excitation of a Stokes
process, combined with single photon detection, allows writing a delocalised
mechanical Bell state in the system, signatures of which can then be read out
in the optical field. A measure of entanglement in this protocol is provided by
the visibility of a characteristic quantum interference pattern in the emitted
light.Comment: 8 pages, 5 Figure
Extracting Protocol Format as State Machine via Controlled Static Loop Analysis
Reverse engineering of protocol message formats is critical for many security
applications. Mainstream techniques use dynamic analysis and inherit its
low-coverage problem -- the inferred message formats only reflect the features
of their inputs. To achieve high coverage, we choose to use static analysis to
infer message formats from the implementation of protocol parsers. In this
work, we focus on a class of extremely challenging protocols whose formats are
described via constraint-enhanced regular expressions and parsed using
finite-state machines. Such state machines are often implemented as complicated
parsing loops, which are inherently difficult to analyze via conventional
static analysis. Our new technique extracts a state machine by regarding each
loop iteration as a state and the dependency between loop iterations as state
transitions. To achieve high, i.e., path-sensitive, precision but avoid path
explosion, the analysis is controlled to merge as many paths as possible based
on carefully-designed rules. The evaluation results show that we can infer a
state machine and, thus, the message formats, in five minutes with over 90%
precision and recall, far better than state of the art. We also applied the
state machines to enhance protocol fuzzers, which are improved by 20% to 230%
in terms of coverage and detect ten more zero-days compared to baselines
Picosecond coherent electron motion in a silicon single-electron source
Understanding ultrafast coherent electron dynamics is necessary for
application of a single-electron source to metrological standards, quantum
information processing, including electron quantum optics, and quantum sensing.
While the dynamics of an electron emitted from the source has been extensively
studied, there is as yet no study of the dynamics inside the source. This is
because the speed of the internal dynamics is typically higher than 100 GHz,
beyond state-of-the-art experimental bandwidth. Here, we theoretically and
experimentally demonstrate that the internal dynamics in a silicon
singleelectron source comprising a dynamic quantum dot can be detected,
utilising a resonant level with which the dynamics is read out as
gate-dependent current oscillations. Our experimental observation and
simulation with realistic parameters show that an electron wave packet
spatially oscillates quantum-coherently at 200 GHz inside the source.
Our results will lead to a protocol for detecting such fast dynamics in a
cavity and offer a means of engineering electron wave packets. This could allow
high-accuracy current sources, high-resolution and high-speed
electromagnetic-field sensing, and high-fidelity initialisation of flying
qubits
NMR as evaluation strategy for cellular uptake of nanoparticles
Advanced nanostructured materials, such as gold nanoparticles, magnetic nanoparticles, and multifunctional materials, are nowadays used in many state-of-the-art biomedical application. However, although the engineering in this field is very advanced, there remain some fundamental problems involving the interaction mechanisms between nanostructures and cells or tissues. Here we show the potential of 1H NMR in the investigation of the uptake of two different kinds of nanostructures, that is, maghemite and gold nanoparticles, and of a chemotherapy drug (Temozolomide) in glioblastoma tumor cells. The proposed experimental protocol provides a new way to investigate the general problem of cellular uptake for a variety of biocompatible nanostructures and drugs. © 2014 American Chemical Society
Evidence in Requirements Engineering: A Systematic Literature Review Protocol
Requirements Engineering (RE) is recognized as one of the critical phases in software development. RE has its own journals and conferences where lots of work has been published. As the area is maturing, increasingly large numbers of empirically supported studies have been reported in RE. There is a need to synthesize evidence based RE literature. We plan to systematically investigate evidence based RE studies to see and report state of the art in evidence based RE reported research. This paper aims at providing a systematic literature review (SLR) protocol to describe a process for synthesizing the empirically supported work in the area of RE that will eventually present a state of the art of the field. This SLR intends to not only summarize the empirical data regarding RE but will also be helpful for various practitioners in this field to find out areas of RE rich in terms of tools, techniques, frameworks, models and guidelines to aid in their work. It will also facilitate RE researchers to identify knowledge gaps to recognize needs and chances for future research directions in this field
Shortcuts to adiabaticity in superconducting circuits for fast multi-partite state generation
Shortcuts to adiabaticity provides a flexible method to accelerate and
improve a quantum control task beyond adiabatic criteria. Here we propose the
reverse-engineering approach to design the longitudinal coupling between a set
of qubits coupled to several field modes, for achieving a fast generation of
multi-partite quantum gates in photonic or qubit-based architecture. We show
that the enhancing generation time is at the nanosecond scale that does not
scale with the number of system components. In addition, our protocol does not
suffer noticeable detrimental effects due to the dissipative dynamics. Finally,
the possible implementation is discussed with the state-of-the-art circuit
quantum electrodynamics architecture.Comment: 11 pages, 8 figure
Microfluidic cell engineering on high-density microelectrode arrays for assessing structure-function relationships in living neuronal networks
Neuronal networks in dissociated culture combined with cell engineering
technology offer a pivotal platform to constructively explore the relationship
between structure and function in living neuronal networks. Here, we fabricated
defined neuronal networks possessing a modular architecture on high-density
microelectrode arrays (HD-MEAs), a state-of-the-art electrophysiological tool
for recording neural activity with high spatial and temporal resolutions. We
first established a surface coating protocol using a cell-permissive hydrogel
to stably attach polydimethylsiloxane microfluidic film on the HD-MEA. We then
recorded the spontaneous neural activity of the engineered neuronal network,
which revealed an important portrait of the engineered neuronal
network--modular architecture enhances functional complexity by reducing the
excessive neural correlation between spatially segregated modules. The results
of this study highlight the impact of HD-MEA recordings combined with cell
engineering technologies as a novel tool in neuroscience to constructively
assess the structure-function relationships in neuronal networks.Comment: 18 pages, 5 figure
Photocatalytic nitrogen reduction to ammonia: Insights into the role of defect engineering in photocatalysts
Engineering of defects in semiconductors provides an effective protocol for improving photocatalytic N2 conversion efficiency. This review focuses on the state-of-the-art progress in defect engineering of photocatalysts for the N2 reduction toward ammonia. The basic principles and mechanisms of thermal catalyzed and photon-induced N2 reduction are first concisely recapped, including relevant properties of the N2 molecule, reaction pathways, and NH3 quantification methods. Subsequently, defect classification, synthesis strategies, and identification techniques are compendiously summarized. Advances of in situ characterization techniques for monitoring defect state during the N2 reduction process are also described. Especially, various surface defect strategies and their critical roles in improving the N2 photoreduction performance are highlighted, including surface vacancies (i.e., anionic vacancies and cationic vacancies), heteroatom doping (i.e., metal element doping and nonmetal element doping), and atomically defined surface sites. Finally, future opportunities and challenges as well as perspectives on further development of defect-engineered photocatalysts for the nitrogen reduction to ammonia are presented. It is expected that this review can provide a profound guidance for more specialized design of defect-engineered catalysts with high activity and stability for nitrogen photochemical fixation
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