Recent developments in Digital Loudspeakers have resulted in the introduction of Digital Transducer Arrays (DTA). In most implementations, DTA loudspeakers are driven by PCM encoded audio signals, usually resampled an...
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ISBN:
(纸本)9781604231403
Recent developments in Digital Loudspeakers have resulted in the introduction of Digital Transducer Arrays (DTA). In most implementations, DTA loudspeakers are driven by PCM encoded audio signals, usually resampled and requantised to an appropriate number of bits, in accordance to the number of the transducers constituting the DTA topology. However, given that DTAs generally increase harmonic distortion, especially for off-axis listening positions, optimization in signal encoding and bit-to-transducer assignment, is necessary. Here, a number of novel, alternative strategies are examined, concerning the input signal encoding via PCM-to-PWM conversion, as well as techniques for bit-assignment on the transducers of a DTA. These tests are supported by simulation results and comparisons between these alternative methods, for different operating parameters.
The indoor subarea localization has wide application space in dynamic hotzone identification, indoor layout optimization, store dynamic pricing and crowd flowtrend prediction. The ubiquitous mobile devices provide the...
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The indoor subarea localization has wide application space in dynamic hotzone identification, indoor layout optimization, store dynamic pricing and crowd flowtrend prediction. The ubiquitous mobile devices provide the opportunity for wirelessfingerprinting-based indoor localization services. However, there are two short boardwhere the existing methods have been criticized. One is that a tagging approach requiresa large number of professional surveys for wireless fingerprint construction, whichweakens the scalability of the methods. The other is that the crowdsourcing-basedmethods encounter the cold boot problem in the system initial stage. To address theseissues, the paper proposes a topology optimization approach leveraging the dynamiclogical anchor selection into a subarea localization system. First of all, a newannular-based radio map construction strategy with the feedback selection of logic anchoris designed to release the pressure of site survey. The implementation of this strategyharnesses the characteristics of the indoor building structure and inter subareaoverlapping recognition, without the topology and distribution of physical anchor (e.g.,access points or POIs). Secondly, exploiting the probabilistic support vector machinealgorithm, the target is localized in the corresponding subarea in a real-time ***, the localization error is calibrated with an error recognition ***, massive experiments are implemented on a prototype system. The results showthat the proposed method can decrease the overhead of the system initialization andachieve higher localization accuracy compared with the existing approaches.
Interactions between the solar diurnal tide, semidiurnal tide, internal gravity waves and mean zonal winds in the mesosphere and lower thermosphere are investigated using a quasi-nonlinear time dependent numerical mod...
In recent years, ensemble learning methods show great effectiveness in improving model performance in several applications. Ensemble techniques rely on the incorporation of multiple different models together to get on...
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Different types of mental activity are utilised as an input in Brain-computer Interface (BCI) systems. One such activity type is based on Event-Related Potentials (ERPs). The characteristics of ERPs are not visible in...
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ISBN:
(纸本)1902956648
Different types of mental activity are utilised as an input in Brain-computer Interface (BCI) systems. One such activity type is based on Event-Related Potentials (ERPs). The characteristics of ERPs are not visible in single-trials, thus averaging over a number of trials is necessary before the signals become usable. An improvement in ERP-based BCI operation and system usability could be obtained if the use of single-trial ERP data was possible. The method of Independent Component Analysis (ICA) can be utilised to separate single-trial recordings of ERP data into components that correspond to ERP characteristics, background electroencephalogram (EEG) activity and other components with non-cerebral origin. Choice of specific components and their use to reconstruct "denoised" single-trial data could improve the signal quality, thus allowing the successful use of single-trial data without the need for averaging. This paper assesses single-trial ERP signals reconstructed using a selection of estimated components from the application of ICA on the raw ERP data. Signal improvement is measured using Contrast-To-Noise measures. It was found that such analysis improves the signal quality in all single-trials.
Fault isolation in dynamical systems is a challenging task due to modeling uncertainty and measurement noise,interactive effects of multiple faults and fault *** paper proposes a unified approach for isolation of mult...
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Fault isolation in dynamical systems is a challenging task due to modeling uncertainty and measurement noise,interactive effects of multiple faults and fault *** paper proposes a unified approach for isolation of multiple actuator or sensor faults in a class of nonlinear uncertain dynamical *** and sensor fault isolation are accomplished in two independent modules,that monitor the system and are able to isolate the potential faulty actuator(s)or sensor(s).For the sensor fault isolation(SFI)case,a module is designed which monitors the system and utilizes an adaptive isolation threshold on the output residuals computed via a nonlinear estimation scheme that allows the isolation of single/multiple faulty sensor(s).For the actuator fault isolation(AFI)case,a second module is designed,which utilizes a learning-based scheme for adaptive approximation of faulty actuator(s)and,based on a reasoning decision logic and suitably designed AFI thresholds,the faulty actuator(s)set can be *** effectiveness of the proposed fault isolation approach developed in this paper is demonstrated through a simulation example.
Silicon photonics is a promising technology to address the demand for dense and integrated nextgeneration optical interconnections due to its complementary-metal-oxide-semiconductor(CMOS) ***, one of the key building ...
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Silicon photonics is a promising technology to address the demand for dense and integrated nextgeneration optical interconnections due to its complementary-metal-oxide-semiconductor(CMOS) ***, one of the key building blocks, the silicon modulator, suffers from several drawbacks, including a limited bandwidth, a relatively large footprint, and high power consumption. The graphene-based silicon modulator, which benefits from the excellent optical properties of the two-dimensional graphene material with its unique band structure,has significantly advanced the above critical figures of merit. In this work, we review the state-of-the-art graphenebased silicon modulators operating in various mechanisms, i.e., thermal-optical, electro-optical, and plasmonic. It is shown that graphene-based silicon modulators possess the potential to have satisfactory characteristics in intra-and inter-chip connections.
There have two effective ways to improve the overall efficiency of the object-based distributed storage system, one is network caching technology and the other is metadata server cluster load balancing strategy. Under...
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This article describes the first implementation of a hardware architecture that solves the problem of collision detection for an arbitrarily complex collection of arbitrarily complex objects in a visual simulation sys...
This article describes the first implementation of a hardware architecture that solves the problem of collision detection for an arbitrarily complex collection of arbitrarily complex objects in a visual simulation system in real time. Resolving all collisions between N moving objects in real-time requires O(N2) calculations are performed every frame time. One possibility is to have one central processor performing all the calculations. This quickly reaches a performance limit. Alternatively, N processors can each do O(N) calculations, since moving objects only require calculations to be performed relative to themselves. Moreover, only active objects need to do calculations. The hardware architecture described in this article uses this calculation partitioning to solve the collision detection problem. There are a number of collision detection chips per active object, which compare that active object's polygons against all other polygons within the pilot's 360-degrees viewing range. The number of collision detection chips per active object is proportional to the polygon complexity of an object-not the number of objects in the scenario. Further, we describe the model governing the collision detection hardware design and how the hardware is to be incorporated in the visual simulation system.
This work presents a technique of changing timbres of sounds by manipulating harmonic envelopes in spectral bands, called Cross-Vocoding. The spectrum of the source sound is divided into fairly narrow bands, and the s...
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