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In a wireless body area networks (WBAN) with integrated sensor hubs, the proposed MAC protocol is a TDMA-based schedule used in active superframe interleaving and beacon shifting defined by the IEEE 802.15.6 standard. It considers the human dynamics and traffic information to meet the different QoS requirements of each sensor, improve bandwidth utilization and reduces packet collisions within networks...
In this paper, a single inductor-single sensor based photovoltaic optimizer with an optimal current point tracking strategy is proposed. With only one inductor, one sensor and one MPPT unit, this optimizer can not only make all submodules output their individual maximum powers, but also utilize the least components compared with current solutions, greatly reducing the size and cost of photovoltaic...
With the progress of the network and technology, the perfect combination of mobile intelligent terminal and internet, people are increasingly dependent on intelligent terminals. So, it was very necessary of a model for assessing the security performance of mobile intelligent terminals, especially to establish the objective model of the security performance of mobile intelligent terminal. In this paper,...
In this paper, two dimensional angle estimation using a new array structure named separate nested acoustic vector sensor (AVS) array is studied. Unlike traditional AVS array, where the pressure sensor and velocity sensors are collocated in space, the separate nested AVS array has two separate and nested subarrays including the pressure sensor array and the velocity vector sensor array. With the extended...
In recent years, the wireless body area network (WBAN) has become a heated topic in research, but its quality of service (QoS) has not received enough attention. The two operation modes of IEEE802.15.4 are analyzed, and the slotted CSMA/CA mechanism is found more suitable for the WBAN. With the simulation tool OPNET the network delays are proved to change in accordance with the parameter values of...
Social data from online social networks is expanding rapidly as the number of users and articles posted increases, making public opinion analysis a greater challenge. Real-time topic detection is a key part of public opinion analysis. The complex data processing involved in traditional clustering and text categorization can lead to time delays in topic detection. In this paper we construct similar...
It is well known that over-voltage induced by re-ignition is dangerous for the safety and stable operation of power system. The objective of this paper is to determine the effect of load parameters on multiple re-ignitions due to dielectric breakdown in vacuum circuit breakers after interruption of small inductive currents at short gaps. A sheath development model was used to analyze the dielectric...
Lithium ion batteries play vital roles in the development of electric vehicles (EVs). To shorten charging time, increase charging efficiency and reduce battery temperature variation, multi-segment charging (MSC) strategy is studied in this paper. Compared to constant current (CC) charging, MSC divides charging process into several segments according to fast charging theory. Taguchi method is applied...
As the power source of electric vehicles, lithium-ion batteries directly affect the performance and life of electric vehicles. The charging strategy of lithium-ion battery directly affects the charging speed, energy consumption and life of the battery. In view of above problems, the multi-segment constant current charging strategy of lithium-ion battery is designed and the particle swarm optimization...
In this paper, direction of arrival (DOA) estimation using sum co-array of coprime arrays is studied. The array geometry can be represented as the kronecker product of those of two coprime arrays. This array structure can reduce the aperture loss when extracting the subarrays, which are jointly used to achieve high resolution and unique DOA estimation via low computational propagator method. Compare...
The rapid proliferation of devices of the Internet of Things requires a vast network of heterogeneous devices to maintain the ability to communicate rapidly and seamlessly. The transition to delay sensitive Tactile Internet applications would demand on a new information and communications infrastructure. In our previous work, we have proposed a fast Location basEd Source Switching (LESS) mechanism...
PV systems are influenced by disproportionate impacts on energy production due to mismatch cases frequently. The occurrence of multiple maximum power points (MPPs) adds complexity to the tracking process in different PV systems. However, current Maximum Power Point Tracking (MPPT) techniques exhibit limited performance. This paper introduces an Enhanced simulated annealing (ESA) based GMPPT technique...
Shunt active power filters (SAPF) generally compensate harmonic current of centralized non-linear loads, which may cause undesired economical burden for networks with distributed harmonic sources. This paper proposed an SAPF predictive control method based on online impedance measurement which can suppress the network-wide harmonics systematically in an optimized way.
As a dedicated solar radio interferometer, the MingantU SpEctral RadioHeliograph (MUSER) generates massive observational data in the frequency range from 400 MHz to 15 GHz. The image quality depends strongly on the phase calibration and imaging algorithms. And, clean, which are really extraordinarily time consumption deconvolution operations, is an essential step to get high-quality images. In this...
A phase-sensitive optical time domain reflectometry sensing system based on Ultra-weak FBG Array using double pulses is proposed. The principle of this sensing system is elaborated. A series of simulations are carried out to optimize the parameters to increase the sensing distance of this system. The parameters contain reflectivity of UWFBG, the interval between adjacent UWFBGs and pulse width. The...
Time delay estimation in multipath environments is important for many applications in the fields of radar, sonar, communication and so on. In this paper, we propose a method based on compressed sensing for time delay estimation. In the proposed method, the signal in time domain is first converted into frequency domain, which tends to convert the problem to a parameter estimation of sinusoidal signals...
Power devices short circuit or open circuit fault can have serious impact on the reliability of the photovoltaic inverter system during the operational process. On the basis of analysis of the fault characteristics and types with neutral point clamped three-level photovoltaic inverter as the research object, fault diagnosis logic is given. Fault tolerant control strategy for three-level photovoltaic...
Petrochemical hydrogenation unit has often been operated under high-temperature, high-pressure or critical hydrogen condition, probably resulting in severe accident such as leaking, fire and explosion. The reasonable emergency response program is an important guarantee for controlling the spread of risk and reducing the consequence of accident. There are a lot of database files in petrochemical units,...
This paper presents a novel method for joint frequency and angle estimation of incoming signals. Two-layers compressed sensing method is used to obtain direction wave number and frequency parameters respectively. The algorithm provides high resolution and accuracy in both frequency and direction of arrival (DOA) estimation over the frequency range under the condition of small signal to noise ratio...
This paper proposes a feature fusion based method for JPEG double compression detection. When extracting the fusion features, the Markov model of the first digits of DCT coefficients and the difference of adjacent coefficients extracted from JPEG images are fused to a big feature vector, and then the Sammon mapping method is applied for dimensionality reduction. Finally, the Support Vector Machine...
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