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The purpose of this research is to develop a high-efficiency, low-cost, and easy-to-use tracking system for vehicles, and it is expected that the system can be extended to areas such as service robots, autonomous driving, and manufacturing. In this paper, we introduced an object detection algorithm based on convolutional neural networks to realize face recognition, which has better efficiency and robustness than traditional machine learning methods. With the concept of edge computing, we deployed the model on the local embedded system to improve the information transmission and security issues of cloud computing. In order to realize the tracking system, this paper builds a mecanum-wheel vehicle with omnidirectional mobility, and proposes a parallel-cascade PID controller architecture based on the mecanum-wheel vehicle. The fixed distance linear tracking control can be realized through the dual-loop feedback control of distance and yaw angle; moreover, the vehicle slipping which is caused by difference rotation speed can be improved. Finally, through algorithm optimization, controller parameter adjustment, and system integration, an omnidirectional mobile vehicle with recognition and tracking functions is realized. The experiment results indicate that the system is stable and robust during actual operation. [ABSTRACT FROM AUTHOR]

The predicting correction technique (PCT) is proposed to achieve an adaptive on-time control for ripple-based buck converters. The switching frequency $f_{{\rm SW}}$ variation is suppressed when the PCT technique considers complete parasitic resistances of the components and devices. Even without extra clock-controlled circuits and current sensing circuits, the buck converter operates with a nearly constant $f_{{\rm SW}}$ over a wide load range. Parasitic resistances almost cause no influence and restriction on $f_{{\rm SW}}$. Only input voltage is used to predict the adaptive on-time. Measurement results show only 0.32% in $\Delta f_{{\rm SW}}/f_{{\rm SW}}$ and 5.7 kHz/A in $\Delta f_{{\rm SW}}/\Delta I_{{\rm LOAD}}$ in case of 1.4 A load current change and $f_{{\rm SW}}$ is 2.5 MHz. Consequently, a pseudo-constant $f_{{\rm SW}}$ with well-defined noise spectrum strongly benefits the solution of electromagnetic interference (EMI) for system-on-a-chip (SoC) applications. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, synchronization of Sprott chaotic systems and its application in secure communication are presented. We first utilize a proportional-integral-derivative (PID) control scheme to solve the synchronization problem of chaotic systems. Then for the purpose of application to secure communication, a state signal of the analog chaotic system is converted to a digital train with variable pulse width (square wave with random frequency) by voltage controlled oscillator (VCO). The original digital message is masked by the digital train generated from VCO in the chaotic transmitter via a logical exclusive-OR (XOR) operation and it can be successfully recovered by another VCO and XOR operation at the chaotic receiver due to the synchronization. To verify the system performance, basic electronic components containing operational amplifiers (OPAs), resistors and capacitors are used to implement the proposed PID-based chaotic secure communication system. Finally, the experimental results validate the proposed chaotic communication approach. [Copyright &y& Elsevier]

Polylactide (PLA) was mixed with poly(vinylidene fluoride) (PVDF) and spun into nonwoven mats via electrospinning technique using a co-solvent system of N,N-dimethylformamide (DMF) and acetone. The resulting mats were subject to characterization including contact angle, infrared spectrometry (IR), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), tensile test, and examined using scanning electron microscope (SEM). With such a co-solvent system, the viscosity was measured, and the average fiber diameter achievable without beads for PLA, PLA/PVDF, and PVDF mats was 252 nm, 209 nm, and 355 nm, respectively. Infrared spectra showed that electrospinning can induce crystallization of PVDF. Both α and β phases were observed from the IR and WAXD results. From the results of DSC, the PLA/PVDF mats exhibited higher melting temperature but lower crystallinity than both PLA and PVDF. The tensile strength of PLA/PVDF was lower than those of PLA and PVDF. By applying stretching during eletrospinning, the ratio of strength in machine direction (MD) to that in cross direction (CD) was increased to 2. In addition, electrospun PLA/PVDF mats exhibited higher cell proliferation for L929 fibroblasts than both PLA and PVDF mats. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the evolutionary programming (EP)-based proportional-integral-derivative (PID) control design is presented for synchronization of chaotic systems with application in secure communication. A PID controller is developed via the EP algorithm. By using the EP algorithm, optimal control gains in PID controlled chaotic systems are derived such that a performance index of integrated absolute error (IAE) is as minimal as possible. Moreover, as an application, the proposed EP-based PID control scheme is then applied to a chaotic secure communication system. To verify the system performance, basic electronic components containing OPA, resistor and capacitor elements are used to implement the proposed PID-based chaotic secure communication system. Finally, both simulation results and the circuit experiments demonstrate the proposed PID scheme’s success in the communication application. [Copyright &y& Elsevier]

Abstract: This article describes a highly accurate and instant-response ultrasonic system for measuring air temperature using multi-frequency continuous waves (MFCW). The proposed system uses a method heretofore applied only to radio frequency distance measurement but not to air-based ultrasonic systems. The method presented here is based upon the comparative phase shifts generated by three continuous ultrasonic waves of different but closely spaced frequencies. It uses the ultrasonic measurement of the changes in the speed of sound in the air to determine the temperature of bulk air. The changes in the speed of sound are calculated from phase shift of multi-frequency continuous wave. In our experiment, in a temperature-controlled chamber, we placed two 40kHz ultrasonic transducers face to face with a constant distance in between. We use MFCW of 40/41.8/42kHz. A single-chip microprocessor-based signal generator and phase detector are used to record and calculate phase shift and temperature. In a proof-of-concept experiment, it is accurate to ±0.4°C from 0 to 80°C with 0.05% resolution and temperature changes are instantly reflected within 100ms. [Copyright &y& Elsevier]

A novel technique for transmission of information through visible light communication (VLC) is developed in this study. A light-emitting diode is used as the light source at the transmitting side to send the encrypted information. At the receiving side, a light sensor, OPT-101, is used to receive the light signals that carry the encrypted information. The Arduino Due microcontroller board is used for digital signal processing at both the transmitting and receiving sides. Furthermore, to prevent the transmitted message from being intercepted, two chaotic systems, a master and a slave, with a synchronization controller are designed to obtain the transmitted audio signals. The design enables not only a VLC system with the light transmission path as a straight line (so that data cannot be stolen) but also the encryption of the audio signals with the chaotic system (Rössler system) to enhance data transmission security. The effectiveness of this system is then experimentally verified. [ABSTRACT FROM AUTHOR]

Abstract: Background: Falling onto the outstretched hand is a major cause of upper extremity injury. The overall objectives of this study were to develop an experimental model for elbow load during a simulated fall onto one-armed arrest using three different forearm axially rotated postures as alternative fall arrest strategies. Additionally, the relationship between the elbow flexion angle and different axially rotated postures were also investigated. Methods: Fifteen healthy young male Taiwanese graduate students with an average age of 23years were studied. Subjects performed a one-armed arrest of a 5cm fall onto a force plate. Each subject fell onto the force plate with his forearm 45° axial externally rotated (ER), non-rotated (NR), and 45° axial internally rotated (IR) postures. Kinematics and kinetics of the upper extremity were calculated and analyzed by using laboratory-developed motion analysis procedures. Findings: The valgus–varus shear forces in the ER group were 1.4 times greater than the NR group, and 2.7 times greater than the IR group. The elbow joint remained at almost full extension in the ER (3.9°) group, while elbow flexion angle was observed in the NR (24.6°) and IR (40.3°) groups. Interpretation: A fall onto the outstretched hand with an externally rotated forearm should be avoided in order to reduce excessive valgus–varus shear force on the elbow joint. Knowledge of elbow kinematics and kinetics during a forward fall with various forearm axially rotated posture may be helpful in preventing injuries. [Copyright &y& Elsevier]

Abstract: Cytosolic phospholipase A2 (cPLA2) plays a pivotal role in mediating agonist-induced arachidonic acid release for prostaglandin (PG) synthesis during stimulation with interleukin-1β (IL-1β). However, the mechanisms underlying IL-1β-induced cPLA2 expression and PGE2 synthesis by canine tracheal smooth muscle cells (CTSMCs) have not been defined. IL-1β induced cPLA2 protein and mRNA expression, PGE2 production, and phosphorylation of p42/p44 MAPK, p38 MAPK (ATF2), and JNK (c-Jun) in a time- and concentration-dependent manner, determined by Western blotting, RT-PCR, and ELISA, which was attenuated by the inhibitors of MEK1/2 (U0126), p38 MAPK (SB202190), and JNK (SP600125), or transfection with dominant negative mutants of MEK1/2, p38, and JNK, respectively. Furthermore, IL-1β-induced cPLA2 expression and PGE2 synthesis was inhibited by a selective NF-κB inhibitor (helenalin) or transfection with dominant negative mutants of NF-κB inducing kinase (NIK), IκB kinase (IKK)-α, and IKK-β. Consistently, IL-1β stimulated both IκB-α degradation and NF-κB translocation into nucleus in these cells. NF-κB translocation was blocked by helenalin, but not by U0126, SB202190, and SP600125. MAPKs together with NF-κB-activated p300 recruited to cPLA2 promoter thus facilitating the binding of NF-κB to cPLA2 promoter region and expression of cPLA2 mRNA. IL-1β-induced cPLA2 expression and PGE2 production was inhibited by actinomycin D and cycloheximide, indicating the involvement of transcriptional and translational events in these responses. These results suggest that in CTSMCs, IL-1β-induced cPLA2 expression and PGE2 synthesis was independently mediated through activation of MAPKs and NF-κB pathways and was connected to p300 recruitment and activation. [Copyright &y& Elsevier]

Abstract: This study used batch reactors to characterize the rates and mechanisms of elemental release during the interaction of a single bacterial species (Burkholderia fungorum) with Columbia River Flood Basalt at T =28°C for 36 days. We primarily examined the release of Ca, Mg, P, Si, and Sr under a variety of biotic and abiotic conditions with the aim of evaluating how actively metabolizing bacteria might influence basalt weathering on the continents. Four days after inoculating P-limited reactors (those lacking P in the growth medium), the concentration of viable planktonic cells increased from ∼104 to 108 CFU (Colony Forming Units)/mL, pH decreased from ∼7 to 4, and glucose decreased from ∼1200 to 0μmol/L. Mass-balance and acid–base equilibria calculations suggest that the lowered pH resulted from either respired CO2, organic acids released during biomass synthesis, or H+ extrusion during uptake. Between days 4 and 36, cell numbers remained constant at ∼108 CFU/mL and pH increased to ∼5. Purely abiotic control reactors as well as control reactors containing inert cells (∼108 CFU/mL) showed constant glucose concentrations, thus confirming the absence of biological activity in these experiments. The pH of all control reactors remained near-neutral, except for one experiment where the pH was initially adjusted to 4 but rapidly rose to 7 within 2 days. Over the entire 36 day period, P-limited reactors containing viable bacteria yielded the highest Ca, Mg, Si, and Sr release rates. Release rates inversely correlate with pH, indicating that proton-promoted dissolution was the dominant reaction mechanism. Both biotic and abiotic P-limited reactors displayed low P concentrations. Chemical analyses of bacteria collected at the end of the experiments, combined with mass-balances between the biological and fluid phases, demonstrate that the absence of dissolved P in the biotic reactors resulted from microbial P uptake. The only P source in the basalt is a small amount of apatite (∼1.2%), which occurs as needles within feldspar grains and glass. We therefore conclude that B. fungorum utilized apatite as a P source for biomass synthesis, which stimulated elemental release from coexisting mineral phases via pH lowering. The results of this study suggest that actively metabolizing bacteria have the potential to influence elemental release from basalt in continental settings. [Copyright &y& Elsevier]

To broaden the application of antibacterial catalysts, ZnO/Ag 2 O composite thin films with different Ag 2 O contents have been successfully synthesized on non-woven fabric at room temperature by radio frequency (RF) sputtering with a single ceramic target formed by hot pressing ZnO/Ag 2 O nanocomposite powder in Ar atmosphere at 180 °C for 30 min. The composite thin films were also sputtered on glass substrates for characterizations. The best sputtering condition was found with the Ar/O 2 gas flow ratio at 7:1 to obtain pure Ag 2 O thin film. The deposition of Ag 2 O nanoparticles on commercially available ZnO particles was also confirmed by HR-TEM prior to hot pressing for synthesizing ceramic targets. In this work, an appropriate amount of Ag 2 O incorporated in the composite film was endeavored by forming p – n junction to lower the cost without decreasing bactericidal ability of composite film. The amount of 45 wt% Ag 2 O in composite thin film to provide bactericidal effect was found to be as good as pure Ag 2 O. The feasibility in bactericide is due to the light sensitization of low bandgap Ag 2 O and the formation of nano p – n heterojunction between p-type Ag 2 O and n-type ZnO for efficient photo carrier separation. The dependence of antibacterial effect of ZnO/Ag 2 O thin films on the Ag 2 O content is demonstrated and elucidated in this work. [ABSTRACT FROM AUTHOR]

The dynamic bootstrap voltage (DBV) technique is proposed to keep high efficiency over wide ranges of load currents for high-power universal serial bus devices. The silicon area of the embedded power management with the DBV technique in the system-on-a-chip can be effectively reduced to 50% of the conventional design with a P-type high-side power MOSFET. Test chips fabricated in 0.25-μm CMOS process showed a 92% peak efficiency from 1 mA to 1 A. The maximum driving current was higher than 5 A, and the efficiency was 88%. Compared with the efficiency of the converter without the DBV technique, the efficiency of the converter with DBV technique was improved by about 28%. [ABSTRACT FROM PUBLISHER]