At present, inversing wind vector from aircraft trajectory captured by automatic dependent surveillance-broadcast (ADS-B) is one of the main solutions to obtain wind field in aviation meteorology. However, some algori...
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To improve the test efficiency of inertial navigation components and meet the measurement requirements of multi-type signal output. This paper proposes a dual-mode inertial navigation data acquisition system based on ...
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Collecting resting-state electroencephalography (RSEEG) data is time-consuming and data sets are therefore often small. Because many machine learning (ML) algorithms work better with ample data, researchers looking to...
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ISBN:
(纸本)9798350324471
Collecting resting-state electroencephalography (RSEEG) data is time-consuming and data sets are therefore often small. Because many machine learning (ML) algorithms work better with ample data, researchers looking to use RSEEG and ML to develop diagnostic models have used oversampling methods that may seem to contradict averaging methods used in conventional electroencephalography (EEG) research to improve the signal-to-noise ratio. Using eyes open (EO) and eyes closed (EC) recordings from 3 different research groups, we investigated the effect of different averaging and oversampling methods on classification metrics when classifying people with Parkinson's disease (PD) and controls. Both EC and EO recordings were used due to differences found between these methods. Our results indicated that grouping 58 electrodes into regions-of-interest (ROI) based on anatomical location is preferable to using single electrodes. Furthermore, although recording EO data led to slightly better classification, the number of data points for each participant was reduced and recordings for three participants entirely lost during pre-processing due to a higher level of artefacts than in the EC data.
This paper is concerned with the problem of target geo-location when using forward-looking vehicular-mounted sensors for landmine detection. Intermediate and downward-looking sensors may also be used, but the geolocat...
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ISBN:
(纸本)0819440892
This paper is concerned with the problem of target geo-location when using forward-looking vehicular-mounted sensors for landmine detection. Intermediate and downward-looking sensors may also be used, but the geolocation problem is most complex for the forward-looking sensor. A nonlinear state model for the vehicle is developed and a Kalman filter is combined with the available measurements to estimate the vehicle position and attitude. Knowledge of the sensors specifications along with information as to the location and orientation of the sensor on the vehicle combined with knowledge of the vehicle position and attitude make it possible for one to compute the sensor field-of-view or footprint. Given this, one can then analyze sensor frames and for any detected mines, convert their locations from sensor-frame coordinates to ground coordinates. The vehicle model, the Kalman filter equations, the coordinate transformations and other algorithms required for geo-locating any detected mines are presented and implemented in a simulation. Actual data collected at a test site is then used as input to the simulation. The simulation results indicate that for forward-looking sensors mine geo-location can in fact be accomplished. The actual position estimates are shown to have precision (ellipses of 0.9 confidence level) of less than 0.25 meters for the particular data used. Precise geo-location is one of the essential elements for mine neutralization.
Online feedback-based rating systems are gaining popularity. Dealing with unfair ratings in such systems has been recognized as an important but difficult problem. This problem is challenging especially when the numbe...
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Recent years have seen an increased interest in the use of open-architecture, PC-based controllers for robotic and mechatronic systems. Although such systems give increased flexibility and performance at low unit cost...
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ISBN:
(纸本)9789728865849
Recent years have seen an increased interest in the use of open-architecture, PC-based controllers for robotic and mechatronic systems. Although such systems give increased flexibility and performance at low unit cost, the use of commercial processors and memory devices can be problematic from a safety perspective as they lack many of the built-in integrity testing features that are typical of more specialised equipment. Previous research has shown that the rate of undetected corruptions in industrial PC memory devices is large enough to be of concern in systems where the correct functioning of equipment is vital. In this paper the mechanisms that may lead to such corruptions and the level of risk is examined. A simple, portable and highly effective software library is also presented in this paper that can reduce the impact of such memory errors. The effectiveness of the library is verified in a small example.
Electromagnetic signals from piezoelectric targets in the earth can be generated using seismic sources and measured with electric or magnetic field receivers. The signals are typically small compared to the ambient el...
Electromagnetic signals from piezoelectric targets in the earth can be generated using seismic sources and measured with electric or magnetic field receivers. The signals are typically small compared to the ambient electromagnetic noise and are difficult to identify in unprocessed records. Three dataprocessing algorithms involving stacking, low-pass filtering, and sinusoid subtraction have been developed to enhance the signal-to-noise ratio of piezoelectric data acquired during field experiments. In addition, an analytic modelling technique has been developed to investigate the relationship between seismic and piezoelectric signals.
The stacking technique, designed for use with repetitive seismic sources, employs a robust triggering algorithm that enables it to be used effectively even when the trigger signal is poor. High frequency noise is attenuated using a zero phase frequency domain low-pass filter with variable cut-off frequency and slope. The sinusoid subtraction technique is used to remove powerline noise which occurs at frequencies of 60 Hz and its harmonics. The amplitude and phase of each harmonic are estimated by calculating the Fourier series coefficients for that frequency. A sinusoid having the estimated amplitude and phase is then subtracted from the data to remove the harmonic. Remarkable improvements in the signal-to-noise ratio have been achieved by sinusoid subtraction as powerline noise levels typically exceed piezoelectric signal amplitudes by factors ranging from five to a few hundred times.
For purposes of analytic modelling, a piezoelectric target is represented by a number of spheres each of which become independently polarized during the passage of a spherical elastic wave. The electric potential at a point in a uniform conductive medium surrounding the target is estimated by summing the potentials due to each of the polarized spheres. It is shown that the form of the electric potential time series generated by a uniformly polarized targe
This paper introduces to you a kind of micro-instrumentation composed of the sensor, the condition amplifier, the A/D converter, the memory, the controller, the interface circuit and the cell. It is of small size, cap...
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This paper introduces to you a kind of micro-instrumentation composed of the sensor, the condition amplifier, the A/D converter, the memory, the controller, the interface circuit and the cell. It is of small size, capable of working under high impact acceleration and high environmental temperatures. It is of very low power consumption, leadless and can be situated into the body of an object being measured, for example, in the piston of a working engine, on details rotating with high speed, several kilometers deep in an oil-well, in the flighting projectile, on the gearing gear and in the bore core of a firing artillery. Suitable for any situations in which it is difficult to set leads, it records signals needed during the working process of the objects being measured and then is taken out after the process finishes and the data of it can be read and processed by a computer. This article means to reveal the configuration principle of the device and to discuss fundamentals of memorized testing and measuring, accuracy guarantee, ASIC and some typical examples.
In this paper, the problem of target location is investigated in the distributed multiple-input multiple-output (MIMO) radar based on coherent processing. At the modelling stage, the distributed MIMO radar is divided ...
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ISBN:
(数字)9798331515669
ISBN:
(纸本)9798331515676
In this paper, the problem of target location is investigated in the distributed multiple-input multiple-output (MIMO) radar based on coherent processing. At the modelling stage, the distributed MIMO radar is divided into three separated subarrays, where both transmit and receive functions are used in subarrays 1 and 3, while only receive function is adopted in subarray 2. Furthermore, a small frequency increment is introduced among different antenna elements in the subarray 1, in the meantime, a phase modulating operation is performed for various antenna elements in the subarray 3. In this respect, the target location performance can be improved significantly by means of the transmit modulation in subarrays 1 and 3. Under the circumstances, the model of target location is established, and a two-step estimation technology is shown, where a small location sector with respect to targets are firstly obtained, and the accurate location are further estimated. Specifically, in order to reduce the computational cost required by the multi-dimensional search procedures, an alternating procedure is developed by a sequence of 1-D searches obtained alternating between the optimization over each variable keeping the other fixed. Numerical results corroborate the effectiveness of the developed methods for the target location with distributed MIMO radar based on coherent processing.
A new coherent Doppler lidar engine has been developed for wind sensing. This new sub-system is consist of a compact optical transceiver board stacking on a FPGA based signal processor board which has small foot print...
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A new coherent Doppler lidar engine has been developed for wind sensing. This new sub-system is consist of a compact optical transceiver board stacking on a FPGA based signal processor board which has small foot print of 26 × 10cm. In the optical transceiver board a pulsed serrodyning transmitter combined with a heterodyning receiver using commercial off the shelf components of the digital coherent optical communication. In the signal processor board, a system on chip embedded processors and a FPGA is used for not only controlling the optical transceiver but also executing lidar dataprocessing without any external host computer, leading to realization of an ultra-compact wind sensing system. Preliminary experiments of line of sight wind velocities with this new lidar sub-system also presented for demonstration.
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