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In this paper, the broadband dielectric characteristics of PEEK material used in press pack IGBT devices are measured by the method of frequency-domain dielectric spectroscopy under temperatures from −40 °C to 180 °C and frequencies from 10 mHz to 1 MHz. The mechanism of the broadband dielectric response of PEEK material is analyzed and can be accurately described by dual-relaxation Cole-Cole model. The effects of temperature on broadband dielectric characteristics of PEEK material are analysed with thermal analysis results of Differential Scanning Calorimeter. When the temperature is above the glass transition temperature (153.5 °C), the complex relative permittivity of PEEK material increases sharply. The results of this paper can provide useful references for insulating packaging design of press pack IGBT devices under electrothermal composite stress.

With the significant increase in Topology and Orchestration Specification for cloud applications (TOSCA) orchestration services on the Network Functions Virtualization (NFV) cloud platforms. We apply the TOSCA metadata model to orchestrate NFV virtual applications and implement the orchestration system based on the Network Function Virtualization (NFV) Management And Orchestration (MANO) architecture to deploy these virtual applications to the virtual network function (VNF) as the part of cloud services. The proposed orchestration system uses TOSCA service templates to orchestrate virtual applications without complex schemes. And in the end we evaluate the performance for orchestrating and automating cloud services in our cloud environment.

This paper presents a novel double-fed flux-modulation (DF-FM) machine which offers an effective electric solution for electric vehicle (EV) propulsion. This design can realize adjusted speed and torque transmission without planetary gearbox and brush system in EVs. Main advantages of this design involve high torque density, wide speed range operation and low friction loss. The steady and transient performance of this newly proposed DF-FM machine is analyzed using finite element method (FEM).

We studied the impact of optical pulse coding techniques on Brillouin optical time-domain analysis (BOTDA) systems experimentally. The results show that complementary-coding-based schemes can provide significant enhanced signal-to-noise ratio (SNR) to the BOTDA system. Using complementary coding, the average time can be reduced significantly and so does the measurement time. The complementary-coded pulses with individual pulse duration of 0.1 ns allowed us to realize temperature sensing over 50 m of single-mode fiber with 1-cm spatial resolution.

This paper presents a novel space-time adaptive processor with digital beam forming algorithm based on least mean squares (LMS) method. Furthermore, the omnidirectional optimization principle for the algorithm applied in satellite navigation field is introduced. The algorithm minimizes the deviation of the radiation pattern due to the edge effect of asymmetric substrate in the miniaturization design of antennas. The anti-jamming performance of the introduced algorithm is verified through the experiment of radiation pattern, satellite signal receiving experiment and anti-jamming experiment.

This paper described the design and implementation procedure of Transmission Control Protocol (TCP) hardwiring and TCP offloading engine based on Field Programmable Gate Array (FPGA). The design consists of several modules, and the connection among modules is implemented by buses. The result shows that some functions are realized in this design. The most contribution of this paper is that the design founds the base of Transmission Control Protocol/Internet Protocol (TCP/IP) hardwiring and offloading engine.

There are huge amounts of User Generated Contents (UGCs) consisting of authors' articles of different themes and readers' comments in social networks every day. Generally, an article often gives rise to thousands of readers' comments, which are related to specific points of the originally published article or previous comments. Hence it has suggested the urgent need for automated methods to implement the content linking task, which can also help other related applications, such as information retrieval, summarization and content management. So far content linking is still a relatively new issue. Because of the unsatisfactory of traditional ways based on feature extraction, we look forward to using deeper textual semantic analysis. The Word Embedding model based on deep learning has performed well in Natural Language Processing (NLP), especially in mining deep semantic information recently. Therefore, we study further on the Word Embedding model trained by different neural network models from which we can learn the structure, principles and training ways of the neural network based language models in more depth to complete deep semantic feature extraction. With the aid of the semantic features, we expect to put forward a new method for content linking between comments and their original articles in social networks, and finally verify the validity of the proposed method through experiments and comparison with traditional ways based on feature extraction.

When wireless base station antennas share a tower or site, the electromagnetic compatibility should be considered, one of which is to calculate the antenna isolation. For horizontal isolation, calculation is based on antenna pattern and the traditional far-field boundary is d>2D2/λ. In practical scenarios of antenna co-site, however, antenna distance cannot fit these boundary conditions. Regarding this issue, Magnitude Error on Sphere (MES) is defined as a new indicator of antenna far-field and near-field approach degree. The analysis has shown that the distance boundary in horizontal isolation calculation can be set as d>8λ for typical base station antenna structure. While for vertical isolation calculated by I v (dB)=28+401g(d/λ), the distance boundary can be set as d >4λ.

As has been shown by our testing, the propagation loss (PL) of vertically-polarized (VP) transmitting and horizontally-polarized (HP) receiving is larger than that of VP transmitting and VP receiving, i.e. the cross polarization loss exists. At wireless covered indoor situation, the PL of HP waves is different with that of VP waves, and the difference is traditionally described as near-earth loss. Consider the cross-polarization loss and near earth loss, a 2×2 orthogonal dual-polarization MIMO system has a total receiving power irrelevant of the polarized angle settings, but the balance of the receiving power is dependent on the angle settings. When the receiving setting is +45°/−45° dual-polarization, the two antennas receive equal power, which reaches equilibrium.

Based on a case study example of a voltage-mode controlled half-bridge inverter, this paper illustrates the slow-scale instability and fast-scale instability phenomena mathematically. An average model for slow-scale instability analysis and a discrete-model for fast-scale instability analysis are presented. The main results are illustrated by simulations. It is shown that the slow-scale instability happens as low frequency oscillation anywhere in a cycle, while the fast-scale instability happens as a period-doubling bifurcation in a local zone. The paper is also extended to include the parallel-connected inverters. Parallel-connected inverters have different properties for both slow-scale and fast-scale instability. Using the similar approach as that used for analyzing the single inverter, the relationships between parameters and slow-scale and fast-scale instability of the parallel-connected inverters are derive.

Digital modulation error parameters, such as error vector magnitude EVM, is important in test and measurement of information system. This paper introduces the technology research progress in the metrology of digital modulation error parameters. First, we point out the basic problems existing in the field, which is about traceability and parameter range of calibration, and describe the relevant research, such as the thinking and technology of the `RF waveform metrology'. Then, we highlight the research progress of our team: 1). The metrology method and system for digital demodulation error parameter based on CW combination, which fits BPSK, QPSK, 8PSK, 16QAM, 64QAM modulation: this method can achieve traceability and error setting ability in a wide range, when standard EvmRms is 1.585%, the expanded uncertainty (k=2) is 0.009%. 2). The metrology method and system for digital demodulation error parameter based on analog AM or PM. 3). The metrology method and system for digital demodulation error parameter based on IQ gain imbalance and phase imbalance. 4). The metrology method and system for digital demodulation error parameter based on analog PM in the aspect of GMSK and FSK modulation. 5). The metrology method and system for digital demodulation error parameter based on Baseband waveform design. Based on these methods, our proposal are given as follows: first, establish public metrology standard for digital modulation error parameters; second, develop a new type of instrument "vector signal analyzer calibrator".

The paper addresses the problems about calibration of vector modulation error such as EVM: first, lacks traceability. Second, lack of error setting. To solve the problems, we proposed “CW combination method” three years ago, which is using combination of CW to calibrate vector signal analyzers in the aspect of MPSK modulation. This paper presents the technical improvement of “CW combination method” in 3 terms: 1, improved traceability formulas of MagErrRms and PhaseErrRms, the new formula is more accurate. 2, improvement on operational method and uncertainty analysis. 3. application in the calibration of high-order modulation such as 16QAM, 64QAM. Based on improved “CW combination method”, metrology standard of EVM, MagErrRms and PhaseErr to calibrate Vector Signal Analyzer is established, and expanded combined uncertainty of EvmRms is less than 0.151% in the range of 0~30%.

The paper addresses the problems about calibration of vector modulation error: first, lacks traceability. Second, lack of error setting. To solve the problems in the aspect of FSK demodulation of vector signal analyzer, we propose new solutions to calibrate vector demodulation error, namely, use analog PM signal with certain parameters, to construct an "equivalent FSK signals" with modulation error. The signals' modulation error such as EVM can be traced to PM frequency and modulation index, and is also adjustable within a wide range. This technique can be used for calibrating VSA and Radio Communication Tester in the aspect of FSK Demodulation Error.

This paper analyzed the interference WCDMA signals to digital terrestrial broadcast television receiver, demonstrated that since WCDMA transmitting power control (TPC) mechanisms, in the most serious interference cases, the uplink or downlink interference will be dominant respectively, so in the interference analysis, uplink and downlink interference should be treat respectively, i.e. the case of uplink and downlink as a single interference source should get consideration priority.

MATLAB programs based on Geometrical Optics (GO) theory were used to calculate the standard uncertainty introduced by the ripple of Anechoic Chamber (AC) in OTA (Over The Air) test. The same method was also used to study the influence of various factors, including high directivity measurement antennas and high performance absorbers. In addition, we likewise found that support structures should be carefully designed to reduce their negative influence on OTA Test ripple quality.

At present, most commonly used techniques in video encoding standards are based on motion compensation, discrete cosine and variable length encoding techniques. These techniques have the advance of improving the compression ratio, but at the same time, the compressed data stream will be very sensitive to transmission errors. In the error-prone network, the frame transmission error, which caused by the amount of video data and the noise of transmission channel, will result in a decline in the quality of received video, and affect its viewing effect. Error concealment techniques have the ability to keep the video quality as much as possible in the conditions of not changing the structure of video stream in the case of transmission errors taking place. To reduce the impact of errors on video quality, an adaptive macro-block (MB) size selection error concealment algorithm that based on edge matching rule is proposed in this paper. By means of using the adjacent macro-block information and the edge matching principle to adaptively select MB size, and based on the distribution and the edge direction of the video frame, made use of the spatial correlation of the image to recover the motion vector of corrupted macro-block and keep the edge feature at the same time. The experimental results demonstrate that the proposed algorithm is superior to common used concealment algorithm of H.264 in both subjective and objective quality.

There is complete sampling theory in time domain and frequency domain, sampling in the modulation domain is a new interesting topic. Mathematical analysis and simulation based on FSK signals reveal the rule: If we sample a signal in the modulation domain with rate f ms , the frequency spectrum will extend periodically at the interval f ms , which means harmonics will appear. And further measurement validates the rule. The rule will help to construct a more complete sampling theory contain "time domain", "frequency domain" and "modulation domain"

With the rapid development of network technology and popularity of virtualization, the importance of developing an adaptive management system for such physical and virtual network environment is obvious increasing. Not simply do the demand systems keep the convenience of virtualization, but conform to the hierarchy of system administration. This article presents the Multilayer Virtual Network Management System, integrated the architecture of network virtualization and the features of multilayer network management. The system is implemented by Net FPGA network development platform and provides a solution of network management for a large scale network. Experiments demonstrate the exact execution of Virtual Network through the policies of network flows and the multilayer management of the proposed system.

Wireless power transfer technology via electromagnetic coupling has been widely used in the planar contactless charging platform. In this paper, a current distribution is deduced to ensure axial component of magnetic field is uniformly distributed in the charging region and zero outside the region. Based on continuous current distributions that can generate even axial component of magnetic field, two transmitting coil structures are proposed. The uniformity of the axial component of magnetic field distribution is confirmed by using the simulation tools. In the case of multiple coils in parallel, the magnetic field distribution near the margin of the charging region changes greatly. This paper analyzed the changes of magnetic field in the case of two coils in parallel, and compared the magnetic field distribution with different coil structures.

Fast Multipole Method (FMM) is applied to calculate the backscattering from 1-D Pierson-Moskowitz dynamic conducting sea surfaces and time series of sea clutter scattering amplitude are obtained under different conditions. The best fitting distributions to the sea clutter amplitude for various frequency, incident angles, wind speed and polarization are acquired. Finally, the computing results are analyzed and discussed in detail.

Introduced Barrick's first-order and second-order sea echo section equations of HF radar. Based on the second-order section equation, this paper submits an algorithm to simulate the sea echo spectrum of HF radar. In the polar coordinate, the method decomposes the sea wave-number space from two dimension to one-dimension, and adds up the second-order spectrum from all one-dimension to form the whole second-order spectrum. The simulation algorithm is easy to program and calculate at a higher speed. The simulated results are identification with those using other methods. And in order to adapt to the actual situation in China, JONSWAP sea spectrum Which is different from PM sea spectrum is used in this paper, the sea echo spectrum simulated is more suited to the sea area in China, It's good to extract the sea state parameters from the spectrum.

To solve the problems of voltage fluctuation, flicker, harmonic and long distance transmission caused by offshore large scale wind farm (WF), a wind power integration scheme by using VSC-HVDC system has been proposed. The WF's voltage has kept in stable by the VSC-HVDC system's reactive power control in real time. There is little low-order harmonics and voltage fluctuation because the power has transmitted through the AC-DC-AC convert. Meanwhile, the transmission capacity has been improved by using HVDC technology and without environment problem because of submarine cable. The VSC-HVDC system's control strategy for the offshore WF integration has been described in detail and has been simulated in PSCAD. It can be seem from simulation result that the direct power control (DPC) and double loop control has good performance in VSC-HVDC system's control and the correctness and effectiveness of the integration scheme has also been verified.

Based on saliency region representation of visual scene, a framework for quantifying the semantic similarity of two video scenes is proposed in this paper. Frame-segment key-frame strategy is used to concisely represent video content in temporal domain. Spatio-temporal conspicuity model for basic visual semantics, a neuromorphic model that simulates human visual system, is used to select dynamic and static spatial salient areas. With pattern classification technique, the basic visual semantics are recognized. Then, the similarity of two visual scenes is calculated according to information theoretic similarity principles and Tversky's set-theoretic similarity. Experiment results demonstrate the framework could compute quantitative semantic similarity of two video scenes.

Artificial immune systems are widely studied. The paper analyzed the stimulation and suppression relationship between antibodies and antibodies versus antigen in an idiotypic immune network, and explained the relationship of PID controller parameters in different phases of control process in the view of analysis above. Based on the explanation, the paper presented a PID control scheme with mechanism of idiotypic immune network regulation to adjust the controller parameters dynamically during the antigen suppression. A method was introduced to overcome the hypersensitivity resulted from high antibody concentration under the condition of repeat antigen invasion. The simulation results to some systems show that the scheme could shorten the calculation time and have the systems controlled effectively.

The proliferation of wireless local area network (WLAN) devices has placed a renewed focus on small, integrated, low cost antennas[1]. In this paper, an improved low cost inverted F antenna with two parasitic elements is presented. Compared with conventional inverted F antenna[2], this antenna can produce wider frequency bandwidth by adding parasitic elements. It can be concluded from the good results of VSWR ≪1.3 at 2.4GHz and VSWR ≪1.4 at 2.5GHz, This antenna has great potential in practical application.

The coupling characteristics were investigated for a photonic crystal fiber when an air hole was filled with a material with higher refractive index. Narrow transmission bands were obtained, with the centre wavelength of the passband determined by the value of the refractive index of the filling material.

The design of LDPC decoders with low complexity, high throughput, and good performance is a critical task. A well-known strategy is to design structured codes such as quasi- cyclic LDPC (QC-LDPC) that allow partially-parallel decoders. Sequential schedules, such as Layered Belief-Propagation (LBP), converge faster than the traditional flooding schedule while allowing parallel decoding of QC-LDPC codes. In this paper, we propose a novel low-complexity sequential schedule called Zigzag LBP (Z-LBP). Current LBP schedules do not allow partially- parallel architectures in the regime of high-rate codes with small- to-medium blocklengths. Our proposed algorithm can still be implemented in a partially-parallel manner in this regime. Z-LBP provides the same benefits as LBP including faster convergence speed and lower frame error rates than flooding.

Arbitrary multilayer plate shielding is investigated by equivalent nonuniform transmission line method. A general formula which can be applied to analyze arbitrary multiplayer plate shielding is proposed. This new method utilizes network parameter matrix of nonuniform transmission line to analyze plate shielding effectiveness for the first time. Owing to the discontinuity of nonuniform transmission line, it is fit to model multilayer plates regardless of the reflection between plates. It makes analysis concise and convenient to take material characteristic into account. In addition, matrix presentation is suit for program and can get result in a few seconds. Special cases of double and fourfold shield are calculated. The accuracy of this method has been validated by comparison to other analytical methods.

The discrete models and learning algorithms of artificial immune network are adopted. The mechanism of artificial immune system is combine with the framework of artificial neural network. The method of RBF neural network should be improved for fitting to any complicated system. An algorithm of artificial immune network for pattern recognition is introduced. The parameter-tuned problems are mainly explored about the basis functions; and a formulation is induced. The precision of pattern identifying is greatly improved. When a typical function is used as the simulation object, the experiment results illustrate this algorithm with high accuracy and convergence speed.

Different from the conventional Reverberation Chamber (RC), ?the Source-Stirred RC? has many advantages but still lacks of deep researches till now. Based on the electric field expression for its planar model, this paper firstly demonstrates the rationality of this new method from the point view of Field Uniformity and Probability Density Function.

When two transmission lines are parallel, one line will disturb another due to inductive and capacitive coupling. This paper presents precise formulas for calculating interference in symbolic form. It illustrates relationship between interference and mutual inductance, capacitance, impedance, attenuation, parallel length clearly. Some new work has been done. One most common situation is considered, in which two lines parallel have attenuation and their length are not equal. In addition, some important cases are used to verify the solution.

This paper is concerned with optimization problems in quasi-metric spaces. Many optimization problems such as vector optimization, set-valued optimization, are unified in the quasi-metric space to have a simple expression. In this paper, optimization problems in quasi-metric spaces are put forward firstly, and then the conclusion that infimum of a lower semi-continuous mapping from a compact set to a quasi-metric space can be reached is received. Subsequently, the proposition that there exists an order cone at lest in each asymmetric norm space is proved. In the end, the conclusion is drawn, which an asymmetric norm is determined by a Banach space and an order cone

The induction motor model passive decomposition scheme was presented. A novel controller scheme based on passivity output feedback equivalence was designed to achieve rotor speed and rotor flux norm tracking for the model of induction motor. The control scheme is based on a structural decomposition of the model into two passive subsystems, namely electrical and mechanical subsystem representing the fast and slow dynamics of the machine, respectively. The system was made passive only by means of output feedback, avoiding the sense of the rotor magnetic fluxes. A complete study was made on the strict passivity and global stability properties of the resultant closed-loop system. The system performance was also evaluated by simulation.

This paper presents a new channel equalizer for OFDM-based communication systems. The channel equalizer consists of the adaptive estimation of channel frequency response (CFR) and the signal recovery. CFR is obtained by the two-dimensional linear interpolation of pilots from the frequency axis and the time axis. To avoid the noise enhancement in signal recovery, maximum-likelihood sequence estimation (MLSE) is applied to improve 1.5dB in SNR while using Rayleigh fading channel model with 30Hz Doppler frequency shift. As compared to the linear equalizer without feedback, the division free approach provides more accurate signal recovery in circuit implementation.

Least squares support vector machines (LS-SVM) is a perfect model-learning algorithm with good accuracy and high speed. Previously, many researches have been done on this algorithm in static modeling problems, but not in dynamic ones. In this paper, we try to solve these problems. Through researches, we propose a new kind of online modeling algorithm based on time window in LS-SVM and use it for modeling of complex nonlinear processes. The purpose of this paper is to show its powerful identification performances. The paper first presents the main mechanism of LS-SVM, and then discusses the optimization algorithm of time window and describes the key action of Karush-Kuhn-Tucker (KKT) optimization condition to this algorithm. The current feature of the model has strong relationship with L updated data. KKT optimization condition decides whether to do the retraining at each updating procedure and avoids unnecessary recalculations. LS-SVM provides great help for increasing the speed during the online modeling. Finally, this algorithm is applied to solving a multivariable modeling problem of a typical complex process in calcination kiln. The simulation results show the good prospect of this algorithm on dynamic identifications of complex nonlinear processes.

This paper is concerned with the quasi-pseudo-metrics of measurable classifiers in pattern recognition problems. A quasi-pseudo-metric of measurable classifiers in probability spaces is proposed, which is an average expense between classifiers. The optimal classifiers in subspace and their estimations are investigated and two important examples are discussed in the quasi-pseudo-metric space.

A 3D surface reconstruction method of medical images based on modularization is proposed in this paper. First, an appropriate segmentation method is applied to its slices using features of the original medical image, and the segmentation result is used as the input of "marching cubes" to generate accurate isosurfaces. Then, a voxel-tracing algorithm is developed based on the relativity of triangles of the isosurfaces. Finally, the vertexes are merged according to some constraints. Experimental results demonstrate that the method was efficient and effective.