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The resonant stability problems of LCL filter have become big challenges for grid-connected inverter in weak grid. This paper takes the effect of non-minimum phase time delay on the ratio between resonance frequency and sampling frequency into account and use it to design the LCL filter. Both LCL resonance frequency and inverter-side inductor and filter capacitor related L1C resonance frequency are...
E-health is one of the domains which will need more and more IoT solutions in the future, as it requires short delays for life-dependency situations and safe local storage spaces for privacy matters. The emergency context demands efficient communication and computing capacities, and the cloud vision as well as traditional TCP/IP way of communication cannot really suit these requirements. New approaches...
Joint pushing and proactive caching holds the promise of significantly increasing the throughput and decreasing the latency of content-centric wireless networks. In this work, we import the pushing and caching mechanism into a traditional packet-oriented network for decreasing the average queueing delay. Since the decreasing relies on extra costs paid for the pushing-caching mechanism, such as the...
The failure rate of doubly-fed induction generators (DFIG) for wind turbine generations was relatively higher than that of direct-driven generators, according to statistical data from some wind power industries. The rotor insulation was a relatively weak part of the insulation system for DFIG because it was normally subjected to a PWM impulse voltage during the long-time operation. In this paper,...
As a meaningful and typical application scenario of Internet of Things (IoT), Internet of Vehicles (IoV) has attracted a lot of attentions to solve the increasingly severe problem of traffic congestion and safety issues in smart city. Information-centric networks (ICN) is a main stream of next generation network because of its content based forwarding strategy and in-network caching properties. Many...
Here we demonstrate, to the best of our knowledge, a tunable 1.5 μm narrow linewidth fiber ring laser using a temperature tuning π-phase shifted fiber Bragg grating (π-PSFBG) for the first time. The π-PSFBG is employed as both a narrow band filter and a wavelength tuning component by a thermo electric cooler (TEC). The tuning range of the laser is 1.29 nm with the precision of 14 pm/°C, and the maximum...
This paper discusses design and parameters identification of a flexible joint robot (FJR) with 2 degrees of freedom. Design of a compact series elastic actuator (SEA) and hardware architecture of FJR, with each joint implemented an SEA, is introduced. To obtain relatively accurate parameters value in dynamic model of FJR, some identification methods of each term are detailed.
In the analysis of plastic packaging SiP product failure, we should not only consider the plastic material and techniques inherent problems, but also the problem that SiP products have a lot of materials, complex structure, and small surface bonding. A type of plastic packaging SiP module function failure after reflow soldering, through appearance inspection, pin electrical characteristic test, X-ray...
A distributed temperature sensor (DTS) utilizing two mode fibers as the sensing fiber is proposed and experimentally demonstrated for long range temperature measurement. Compared with the few mode fiber (FMF) based DTS reported previously, the temperature resolution has been improved to be 1.7 °C at 10 km and 6.0 °C at 20 km, respectively.
We demonstrate a few mode fiber based Raman distributed temperature sensor with wavelet-denoising technique and optimized sensing link. Temperature sensing over 25 km with 3m/7.5 °C spatial /temperature resolution is achieved.
We present VidedWhisfer, a novel approach for unsupervised video representation learning, in which video sequence is treated as a self-supervision entity based on the observation that the sequence encodes video temporal dynamics (e.g., object movement and event evolution). Specifically, for each video sequence, we use a pre-learned visual dictionary to generate a sequence of high-level semantics,...
Nowadays, mobile devices are pervasively used by almost everyone. The majority of mobile devices use embedded-Multi Media Cards (eMMC) as storage. However, the crash-proof mechanism of existing I/O stack has not fully exploited the features of eMMC. In some real usage scenarios, the legacy data persistence procedure may dramatically degrade performance of the system. In response to this, this paper...
Rate-Distortion Optimized Quantization (RDOQ) brings significant improvement of coding performance in High Efficiency Video Coding (HEVC). However, it results in high computational complexity to determine the best quantization levels for each transform coefficient when applying rate and distortion optimization operation. In this paper, we firstly proposed an efficient way to skip the all zero coding...
Traditional internet architecture is challenged and it cannot satisfy the growing demand of todays networks. Information-centric Networks (ICN) is regarding as a promising replacement to meet this trend. The main characteristic in ICN is Content Store (CS), which is used to enable users to retrieve data from nearby nodes instead of remote server. However, with the limited storage capacity of routers,...
The composite insulations consisting of epoxy resin vanish and barrier material are widely used in the insulation system of wind turbine generator (WTG). The insulation system would withstand either the repetitive impulse or the AC stress, and electrical treeing is thought as one of the main contributing factors to the degradation of polymers. In this paper, electrical tree tests in composite insulation...
In order to investigate the effect of adding micro- and nano- inorganic particles in the polymer on the morphology and dielectric properties, the low density polyethylene (LDPE) was used as the matrix, the inorganic micro and nano silicon dioxide (SiO2) were selected as inorganic fillers, origin LDPE and M-SiO2 and N-SiO2 and MN-SiO2 composite materials were respectively prepared by melt blending,...
To overcome the deficiencies of discharge measurement method in open channel, BP neural network (BPNN) is applied in fitting stage-discharge calculation, based on which design a multi cross-section stage-discharge method. BPNN-based single stage-discharge fitting model and BPNN-based dual stage-discharge fitting model were established as the research objects. The stage-discharge data of open channel...
Verification of programs in code-level has attracted more and more attentions since the cost is high to extract models from source code. Most of the approaches available for code-level verification are carried on by inserting assertions into programs and then checking whether the assertions are violated. But in this way, only safety properties can be verified, other temporal properties of programs...
We demonstrate a distributed temperature sensor based on quasi-single mode (QSM) Raman scattering in few mode fibers (FMFs). The FMF allows much larger input pump power before the initiate of stimulated Raman scattering compared with the standard single mode fiber (SSMF) and mitigates the detrimental differential mode group delay (DMGD) existing in the conventional multimode fiber (MMF) based Raman...
A novel Mach-Zehnder interferometer (MZl) based on a pair of long period fiber gratings (LPGs) in an embedded-core hollow optical fiber (ECOF) are proposed and demonstrated experimentally. Two similar LPGs with peak attenuation of approximately 3dB are fabricated in an ECOF by using high-frequency CO2 laser to form an in-fiber MZI. The dependences of the resonant peak on the temperature and the axial...
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