Collaborative actuation of wireless sensor and actuator networks for the agriculture industry.

This paper investigates the deployment of collaborative estimation and actuation scheme of wireless sensor and actuator networks for the agriculture industry. In our proposed scheme, sensor nodes conduct a local estimation based on the Kalman filter for enhancing the estimation stability and further transmit data to the actuator nodes under a multi-rate transmission mode for enhancing the overall energy efficiency of the wireless network. Considering the mutual effect of related clusters, a collaborative actuation scheme of actuator nodes is integrated into our proposed scheme for improving the estimation accuracy and convergence speed. With an accurate estimation of the changes in the environmental parameters, combining the fuzzy neural network with the PID control algorithm, the actuator exerts reliable control over the environmental parameters. Performance evaluations and simulation analysis conducted based on the effects of temperature demonstrate the effectiveness of our proposed scheme in controlling the greenhouse environmental changes for in the agriculture industry.N/

Enhancing Ultrasonic Echoes of Sediment Layer Based on 2 nd Iterative Passive Time Reversal Mirror

Abstract: The amplitude difference of the sediment layer’s echoes is always so large that the acoustic time difference becomes much difficult to get correctly. The existing methods of time varying enhancement for the multipath signal like ultrasonic echo have some limits in de-noising or practical application. This paper employs the second Iterative Passive Time Reversal Mirror to accomplish time varying enhancement for the ultrasonic signal. According the principle of measuring the sediment thickness in borehole by ultrasonic, the paper has established the system model to describe the processing of ultrasonic transmitting through the mud-sediment media, and simplified the channel in a linear, space-invariant, time-invariant multipath channel with two paths. Based on the model, the process of enhancing echoes of sediment layer by 2 nd Iterative Passive Time Reversal Mirror is presented. Using the echoes of sediment with different thickness obtained in lab circumstance, two typical experiments to enhance the echoes have been taken. From the two experiments ’ results we can see, 2 nd Iterative Passive Time Reversal Mirror is sure to give the later arrival echo bigger gain than to the earlier one, thus reduce the amplitude difference of the two echoes. Copyright © 2014 IFSA Publishing, S. L

Enhancing Ultrasonic Echoes of Sediment Layer Based on 2nd Iterative Passive Time Reversal Mirror

The amplitude difference of the sediment layer’s echoes is always so large that the acoustic time difference becomes much difficult to get correctly. The existing methods of time varying enhancement for the multipath signal like ultrasonic echo have some limits in de-noising or practical application. This paper employs the second Iterative Passive Time Reversal Mirror to accomplish time varying enhancement for the ultrasonic signal. According the principle of measuring the sediment thickness in borehole by ultrasonic, the paper has established the system model to describe the processing of ultrasonic transmitting through the mud-sediment media, and simplified the channel in a linear, space-invariant, time-invariant multipath channel with two paths. Based on the model, the process of enhancing echoes of sediment layer by 2nd Iterative Passive Time Reversal Mirror is presented. Using the echoes of sediment with different thickness obtained in lab circumstance, two typical experiments to enhance the echoes have been taken. From the two experiments’ results we can see, 2nd Iterative Passive Time Reversal Mirror is sure to give the later arrival echo bigger gain than to the earlier one, thus reduce the amplitude difference of the two echoes

Tunability and enlargement of omnidirectional transmission frequency range in a photonic heterostructure containing Dirac semimetal

In this study, We theoretically realized the enlargement of the photonic crystal band gap by a photonic heterostructure containing Dirac semimetal layer. At the same time, since the dielectric constant of the Dirac semimetal changes with its Fermi level, based on this characteristic, we have realized the adjustment of the band gap of the enlarged photonic crystal. Comparing a single photonic crystal with a heterostructure photonic crystal, it is found that the photonic band gap of the heterostructure photonic crystal is significantly enlarged, and then the effects of different incident angles and polarized waves on the photonic band gap are analyzed. Based on the above properties, it has potential applications in tunable photonic crystal devices

Application of a Saddle-Type Eddy Current Sensor in Steel Ball Surface-Defect Inspection

Steel ball surface-defect inspection was performed by using a new saddle-type eddy current sensor (SECS), which included a saddle coil and a signal conditioning circuit. The saddle coil was directly wound on the steel ball’s outer bracket in a semi-circumferential direction. Driven by a friction wheel, the test steel ball rotated in a one-dimensional direction, such that the steel ball surface was fully scanned by the SECS. There were two purposes for using the SECS in the steel ball inspection system: one was to reduce the complexity of the unfolding wheel of the surface deployment mechanism, and the other was to reduce the difficulty of sensor processing and installation. Experiments were carried out on bearing steel balls in diameter of 8 mm with three types of representative and typical defects by using the SECS, and the results showed that the inspection system can detect surface defects as small as 0.05 mm in width and 0.1 mm in depth with high-repetition detection accuracy, and the detection efficiency of 5 pcs/s, which meet the requirement for inspecting ISO grade 10 bearing steel balls. The feasibility of detecting steel ball surface defects by SECS was verified

A two-stage classification method for borehole-wall images with support vector machine

<div><p>Analyzing geological drilling hole images acquired by Axial View Panoramic Borehole Televiewer (APBT) is a key step to explore the geological structure in a geological exploration. Conventionally, the borehole images are examined by technicians, which is inefficient and subjective. In this paper, three dominant types of borehole-wall images on coal-rock mass structure, namely, border images, fracture images and intact rock mass images are mainly studied. The traditional image classification methods based on unified feature extraction algorithm and single classifier is not effect for the borehole images. Therefore, this paper proposes a novel two-stage classification approach to improve the classification performance of borehole images. In the first-stage classification, the border images are identified from three kinds of images based on texture features and gray-scale histograms features. For the remaining two types of images, in the second-stage classification, Gabor filter is first applied to segment the region of interest (ROI) (such as microfracture, absciss layer and horizontal cracks, etc.) and the central interference region. Then, using the same feature vector after eliminating the central interference region, fracture images are separated from intact rock mass images. We test our two-stage classification system with real borehole images. The results of experimental show that the two-stage classification method can effectively classify three major borehole-wall images with the correction rate of 95.55% in the first stage and 95% in the second stage.</p></div

Classification accuracy of different kernel functions.

<p>Classification accuracy of different kernel functions.</p

License Plate Detection with Shallow and Deep CNNs in Complex Environments

License plate detection is a challenging problem due to the large visual variations in complex environments, such as motion blur, occlusion, and lighting changes. An advanced discriminative model is needed to accurately segment license plates from the backgrounds. However, effective models for the problem tend to be computationally prohibitive. To address these two conflicting challenges, we propose to detect license plate based on two CNNs, a shallow CNN and a deep CNN. The shallow CNN is used to quickly remove most of the background regions to reduce the computation cost, and the deep CNN is used to detect license plate in the remaining regions. These two CNNs are trained end to end and are complementary to each other to guarantee the detection precision with low computation cost. Experimental results show that the proposed method is promising for license plate detection

Calibration of Ultrasonic Transducer Based on Ultrasonic Logging Instrument for Shaft Sinking

High-precision logging equipment is critical for measuring the borehole diameter and drilling offset in coal mining and petroleum drilling. We propose a module composition and positioning principle for an ultrasonic transducer based on an ultrasonic logging instrument for shaft sinking by drilling (ULISSD) for calculating the reflection distance. The logging distance, which is the primary performance index of a logging system, is determined by using the self-reception sensitivity and error of the ultrasonic transducer in a downhole system. To measure the error between the piezoelectric element of the transducer and the rubber seal of the borehole logging system, we developed an ultrasonic-transducer error-calibration device and a calibration method for a central-air-return-shaft-drilling project. This calibration device can eliminate the inherent error of the transducer and calculate the rate of propagation with high accuracy. The measurement error is reduced by approximately 1.5 mm; thus, the ULISSD measurement accuracy can be effectively improved in central-air-return-shaft drilling