59,098 research outputs found
A low power UART design based on asynchronous techniques
pre-printAbstract-Universal Asynchronous Receiver Transmitter (UART) implements serial communication between peripherals and remote embedded systems. The UART protocol is defined based on fixed frequencies with a sampling method to achieve robustness under reasonable frequency variations between systems. Such design specifications are natural for clocked domains. This work investigates whether this simple clocked hardware protocol can be advantageously implemented using asynchronous design techniques. A full duplex clocked and asynchronous UART are implemented and compared. The asynchronous design results in average power of about one fourth that of the clocked design under standard operating modes
Towards experimental entanglement connection with atomic ensembles in the single excitation regime
We present a protocol for performing entanglement connection between pairs of
atomic ensembles in the single excitation regime. Two pairs are prepared in an
asynchronous fashion and then connected via a Bell measurement. The resulting
state of the two remaining ensembles is mapped to photonic modes and a reduced
density matrix is then reconstructed. Our observations confirm for the first
time the creation of coherence between atomic systems that never interacted, a
first step towards entanglement connection, a critical requirement for quantum
networking and long distance quantum communications
Stabilization of positive switched systems with time-varying delays under asynchronous switching
This paper investigates the state feedback stabilization problem for a class of positive switched systems with time-varying delays under asynchronous switching in the frameworks of continuous-time and discrete-time dynamics. The so-called asynchronous switching means that the switches between the candidate controllers and system modes are asynchronous. By constructing an appropriate co-positive type Lyapunov-Krasovskii functional and further allowing the functional to increase during the running time of active subsystems, sufficient conditions are provided to guarantee the exponential stability of the resulting closed-loop systems, and the corresponding controller gain matrices and admissible switching signals are presented. Finally, two illustrative examples are given to show the effectiveness of the proposed methods
Distance Education Research in Adult Education Journals: A Content Analysis
This study examines adult-centered distance education research articles in two adult education journals: Adult Education Quarterly and the American Journal of Distance Education. Results show that studies of delivery modes and systems; i.e., asynchronous and synchronous modes, learning management systems, television and Web delivery, and course design were most prevalent in both journals. Among topics of interest to adult educators, the self-directed nature of distance learning was predominant. Other topics traditionally associated with adult education, such as access, equity, and social change themes in distance education, were least prevalent in both journals
AFTI/F-16 digital flight control system experience
The Advanced Flighter Technology Integration (AFTI) F-16 program is investigating the integration of emerging technologies into an advanced fighter aircraft. The three major technologies involved are the triplex digital flight control system; decoupled aircraft flight control; and integration of avionics, pilot displays, and flight control. In addition to investigating improvements in fighter performance, the AFTI/F-16 program provides a look at generic problems facing highly integrated, flight-crucial digital controls. An overview of the AFTI/F-16 systems is followed by a summary of flight test experience and recommendations
Holistic engineering design : a combined synchronous and asynchronous approach
To aid the creation and through-life support of large, complex engineering products, organizations are placing a greater emphasis on constructing complete and accurate records of design activities. Current documentary approaches are not sufficient to capture activities and decisions in their entirety and can lead to organizations revisiting and in some cases reworking design decisions in order to understand previous design episodes. Design activities are undertaken in a variety of modes; many of which are dichotomous, and thus each require separate documentary mechanisms to capture information in an efficient manner. It is possible to identify the modes of learning and transaction to describe whether an activity is aimed at increasing a level of understanding or whether it involves manipulating information to achieve a tangible task. The dichotomy of interest in this paper is that of synchronous and asynchronous working, where engineers may work alternately as part of a group or as individuals and where different forms of record are necessary to adequately capture the processes and rationale employed in each mode. This paper introduces complimentary approaches to achieving richer representations of design activities performed synchronously and asynchronously, and through the undertaking of a design based case study, highlights the benefit of each approach. The resulting records serve to provide a more complete depiction of activities undertaken, and provide positive direction for future co-development of the approaches
Associative cued asynchronous BCI induces cortical plasticity in stroke patients
OBJECTIVE: We propose a novel cueâbased asynchronous brainâcomputer interface(BCI) for neuromodulation via the pairing of endogenous motor cortical activity with the activation of somatosensory pathways. METHODS: The proposed BCI detects the intention to move from singleâtrial EEG signals in real time, but, contrary to classic asynchronousâBCI systems, the detection occurs only during time intervals when the patient is cued to move. This cueâbased asynchronousâBCI was compared with two traditional BCI modes (asynchronousâBCI and offline synchronousâBCI) and a control intervention in chronic stroke patients. The patients performed ankle dorsiflexion movements of the paretic limb in each intervention while their brain signals were recorded. BCI interventions decoded the movement attempt and activated afferent pathways via electrical stimulation. Corticomotor excitability was assessed using motorâevoked potentials in the tibialisâanterior muscle induced by transcranial magnetic stimulation before, immediately after, and 30âmin after the intervention. RESULTS: The proposed cueâbased asynchronousâBCI had significantly fewer false positives/min and false positives/true positives (%) as compared to the previously developed asynchronousâBCI. Linearâmixedâmodels showed that motorâevoked potential amplitudes increased following all BCI modes immediately after the intervention compared to the control condition (pâ<0.05). The proposed cueâbased asynchronousâBCI resulted in the largest relative increase in peakâtoâpeak motorâevoked potential amplitudes(141%â±â33%) among all interventions and sustained it for 30âmin(111%â±â33%). INTERPRETATION: These findings prove the high performance of a newly proposed cueâbased asynchronousâBCI intervention. In this paradigm, individuals receive precise instructions (cue) to promote engagement, while the timing of brain activity is accurately detected to establish a precise association with the delivery of sensory input for plasticity induction
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