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Recently Terahertz (THz) radiation from laser-produced plasmas has attracted much interest since plasmas can work at an arbitrarily high laser intensity. We will present the generation of strong THz radiation from femtosecond and picosecond relativistic laser-plasma interactions. THz pulses with energies up to >200 μJ/sr have been demonstrated. The temporal waveform, polarization, and angular distribution...
The impact of both maximal ratio combining (MRC) and relay selection on the physical layer security in wireless communication systems is studied by analyzing some important factors, including the probability characteristic of the legitimate receiver (Bob) and malicious eavesdropper (Eve)'s end-to-end signal-to-noise ratio (SNR), the secrecy outage probability, and the average secrecy channel capacity...
In order to obtain the accurate exposure time in real-time for an on-board camera in different urban environments, the proposed algorithm divides captured image into 5 ×5 sub-areas, calculates each sub-area's average brightness value to get a histogram, analyzes the peak value distribution in histogram to determine what environments the automobile is in. According to the environment the automobile...
Aiming at the task completion and parameters optimization of modular robot when single joint failed, a fault-tolerant trajectory optimization method is proposed in this paper. At first, three fault tolerance performance functions are proposed based on the assessment of joint velocity jumps in different viewpoints. Then, the path planning method using the gradient of the manipulability is introduced...
In mobile Internet era, wireless traffic has become a rare resource and there is no effective ways for users to share their unused traffic with each other. This paper introduces a system solution requiring no sophisticated hardware. An incentive mechanism is designed and implemented in a novel system named Traffic Sharing Platform (TSP) for mobile users, which can optimize network resource configuration...
Because of the limited space and enormous forces in the human foot, researchers generally simplified the foot as a rigid body in the development of lower extremity exoskeletons and biped humanoid robots, which led to unsatisfying performance on flexibility and auto-stability. In this paper, we propose a novel parallel mechanism with seven degrees of freedom (DOF) to realize the main possible movements...
A wearable gait analysis system has been developed for ambulatory measurement of gait in long-term experiments and daily life applications. Based on the measurement results of the developed system in a dynamic validation experiment, we trained neural networks for the estimation of joint angle, joint force, and joint moment using the ground reaction forces (GRFs) and moments in the gait analysis. These...
The relevant problems of software process deviation are increasingly paid attention to, because software processes are subject to permanent dynamic evolution during software process enactment. In Process- centered Software Engineering Environments (PSEE), the enacted software process model is always inconsistence with the observed process obtained by PSEE. In order to address this problem, this paper...
Generally, dimensionality reduction methods, such as Principle Component Analysis (PCA) and Negative Matrix Factorization (NMF), are always applied as the preprocessing part in hyperspectral image classification so as to classify the constituent elements of every pixel in the scene efficiently. The results, however, would suffer the loss of detailed information inevitably. In this paper, deep learning...
Aiming at the velocity jump caused by joint failure of manipulator, a method is proposed to reduce velocity jumps in both Cartesian space and joint space. Based on the analysis of velocity jump, the reduction problem is turned into an optimization problem of finding the best compensation vector for joint velocity. The gradient of the reduced manipulability is applied to represent the weight for joint...
Communication protocol reverse engineering has played an important role in the field of network security. Inferring protocol state machine for unknown protocol is a part of protocol specifications mining. This paper proposed a novel approach in the mining of unknown binary protocol state machine. It allows to automatically generating the state models for binary protocol by listening to network traces...
In this paper, a new miniaturized ultra-wideband (UWB) antenna fed by coplanar waveguide (CPW) is proposed. Gear-shaped structures are employed around the circular disc radiator to impove the current distribution for the antenna miniaturization. Moreover, the gear-shaped structures can produce a wide impedance bandwidth and miniaturization structure. The antenna exhibits a wider bandwidth characteristic...
Mobile Internet access has become the norm rather than an exception in our daily lives, resulting in a large proportion of traffic attributed to mobile devices. To enhance the mobility support in Internet architecture, many research initiatives have devoted to investigating Named Data Networking (NDN) as the fundamental paradigm for the future Internet. NDN supports the consumer mobility by re-issuing...
It has great significance to analyze the kinematics reliability of the manipulator, which can reflect the motion performance comprehensively. In paper, kinematics reliability of manipulator is discussed, and the mathematical description is derived when the manipulator is kinematics reliable. Taking elasticity factors into account, a multi-level model for the pose (position and posture) accuracy of...
Creating and reasoning with goal models is useful for capturing, understanding, and communicating about requirements in the early stages of information system (re)development. However, the utility of goal models is greatly enhanced when an awareness of system intentions can feed into other stages in the requirements analysis process (e.g. requirements elaboration, validation, planning), and can be...
Most of existing network testbeds can only support the experimentation of L2∼L4 forwarding protocols, leaving the evaluation of L4∼L7 applications still a tremendous challenge. This paper pioneers to present the design of sea-cloud innovation environment (SCIE) based on the software defined networking (SDN) and network functions virtualization (NFV) paradigms to support adaptive service-oriented experimentation,...
During grid faults, grid codes required wind turbine (WT) to provide dynamic reactive support within tens of ms as well as maintain grid connection continuously, namely low voltage ride through (LVRT). But owing to the limited DC bus voltage, the rotor side convertor in doubly fed induction generator (DFIG) cannot actually output sufficient voltage to provide reactive support until the rotor-side...
The JUNA cryptosystem is a new kind of multivariable public-key cryptosystem, which is evolved from REESSE1+. The security of a JUNA or REESSE1+ plaintext is based on the anomalous subset product problem (ASPP). An ASPP can be transformed to a special subset sum problem (SSP), and such a SSP is an anomalous subset sum problem (ASSP). An ASSP from REESSE1+ is of low-density, and one from JUNA is of...
This paper proposed an improved control strategy for doubly fed induction generator (DFIG) to enhance its low voltage ride-through (LVRT) capability. Under serious grid faults, the rotor side induced electromotive force (EMF) would exceed the maximum output voltage of the rotor side converter (RSC), leading to over-currents and runaway of DFIG and RSC. To address this issue, a LVRT control strategy...
In order to protect the converters in a doubly fed induction generator (DFIG) based wind turbine during grid fault, a crowbar is the commonly used protection method to realize low voltage ride through (LVRT). Conventionally, the transient process of DFIG with the crowbar is analyzed in an analogous manner to a squirrel-cage induction motor (SCIM). But the crowbar resistance is usually large enough...
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