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This paper proposes and designs a switching cell using paralleled gallium nitride (GaN) high-electron-mobility transistor (HEMTs) in the minimized, symmetric power and gate loops. Based on the design, 1Ω gate resistor was successfully applied to speed up the switching transient. The switching cell can be easy to replace on the mother board thanks to the pluggable connector and the cell owns unique...
Extract Method is a widely used refactoring operation to improve method comprehension and maintenance. Much research has been done to extract codefragments within the method body to form a new method. Criteria used for identifying extractable code is usually centered around degrees of cohesiveness, coupling and length of the method. However, automatic method extraction techniques have not been highly...
Multiple-choice (MC) question is an important form of test to assess the students' academic achievement, especially in the e-learning applications. However, the classical evaluation metrics on MC questions (such as the correctness ratio) only consider the correctness of the final selection but ignore the solving progress of the testee. In the existing literature, the eye-tracking based visual attention...
Classroom observations have been widely used in education over the past couple of decades to measure effective teaching practice. The traditional observation methods rely on human observers, which are short of scalability and objectivity. In this paper, we implement a kind of automatic behavior measurement system, which utilizes the Microsoft Kinect devices to record the students' performance in classroom...
Localization method based on position fingerprint can effectively solve the problems such as high dependence of model and low positioning accuracy in robot auditory system. However, this method requires a large number of reference points to achieve high precision positioning. To solve the problem of low precision under low fingerprint density, a position fingerprint localization method based on linear...
Output voltage of renewable energy resources, such as fuel and solar cells, varies widely with load and environmental condition, so a DC-DC converter should be suitable for wide input-voltage range application and be with low input ripple current. An integrated boost three-phase half-bridge converter is proposed. The boost and three-phase half-bridge converters are integrated to reduce number of switches...
Nowadays, entrepreneurship is drawing more and more attention all over China. Many policies are carried out to promote entrepreneurship and innovation. As the vital implementation subjects of entrepreneurship education, universities are providing strong fiscal, policy support and human resources for students' entrepreneurship practices, launching courses on entrepreneurship as well as encouraging...
Passive spectrum monitoring is important for network diagnosis and radio frequency management in spectrum-sharing wireless networks, i.e., cognitive radio network. Most of the related work focused on the sniffer-channel assignment problem, i.e, assigning proper operational channel to wireless sniffers with the aim of tracking and capturing the target signals or data packets. These approaches were...
Single-stage buck-boost gird-connected inverter is widely used in distributed generation systems because of low cost and high efficiency. However, shoot-through problem exists, so reliability of the system is reduced. In addition, output voltage of renewable energy resources varies widely with load and environmental condition, so voltage stress of switches is high in wide input-voltage range application...
In this paper, a solar panel utilized as a photodetector with simultaneous energy harvesting is proposed in visible light communication (VLC). The solar cell is a self-styled passive device, which can convert optical signals into electrical signals. The generated energy can potentially be used to power user terminals or at least to prolong operation time. This work is an important step towards the...
We experimentally demonstrate a feedback-assisted 1.08 Gb/s orbital angular momentum (OAM)-based underwater-to-air wireless optical link with a floating mirror for beam steering. The experimental results show favorable performance of the proposed feedback scheme in the present of the change of water level.
A pulse amplitude modulation with 4 levels (PAM-4), generated by optical superimposition, is first proposed and experimentally demonstrated for visible light communication (VLC). It can overcome the shortcomings of the PAM-4 signals generated in the electrical domain, with enhanced tolerance to the modulation nonlinearities of a light emitting diode (LED). A proof-of-concept experiment employing two...
Directly modulated semiconductor lasers for underwater wireless optical communication (UWOC) have limitations in output power and beam quality. Diode-pumped solid-state lasers (DPSSLs) have the merits of long lifetime, high stability, large power and good beam quality, which are promising to realize long-each UWOC. We compose a DPSSL with discrete components and measure its key parameters. The bandwidth...
This paper studied downlink multicasting in a wirelessly powered communication network, where multiple energy-constrained relay nodes collaboratively assist the transmissions from a multi-antenna hybrid access point (HAP) to multiple receivers in the downlink. Each relay is equipped with a single antenna and capable of energy harvesting (EH) from the HAP's RF signals in a power splitting protocol...
With the longer period during future manned space missions, the effective implementation of on-orbit maintenance and repair is a necessary means to guarantee the whole life cycle availability of equipment in space. In this paper, we conducted an investigation for on-orbit maintenance and security resource strategies of the International Space Station and other space equipment. And we made a brief...
Due to the increasing complexity of web and client application's structure, security problem has become more and more critical. Among all the threats reported, SQL Injection Attacks (SQLIAs) have always been top-ranked in recent years, and network logs, which are very important for the detection of SQLIA, are often utilized to analyze the user's attacking behaviors. However, the collection of network...
We experimentally demonstrate an underwater wireless optical communication (UWOC) with 1.4-Gbaud 16-QAM signal using Gaussian mode, orbital angular momentum (OAM) mode and Bessel mode at the wavelength of 532 nm. Underwater bubbles effect is also studied and the BER performance is measured.
This paper proposes an initial alignment approach for strapdown inertial navigation system with external information from Doppler velocity logs, aimed at improving navigated accuracy. Based on kalman filtering theory, we make an analysis comparison between two different error models according to simulation results. Then, we respectively discuss the effects that measured velocity errors, height channel...
We demonstrate for the first time dual-channel all-optical AND logic operations based on intra-modal four-wave mixing (FWM) for on-off keying (OOK) signals in a multimode silicon waveguide. Correct temporal waveform sequences and clear eye-diagrams are presented to confirm the AND logic operations in this proof-of-concept work.
Based on fresh random challenge response authentication and key agreement, access control, priority control mechanisms, this paper puts forward a security protection communication protocol to guarantee the data transmission security of electricity acquisition terminal and the acquisition host. From the angle of attack detection, this proposed protocol was proved that can resists replay attack, counterfeit...
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