Abstract:

Compared with the conventional broadside imaging mode used in traditional low-frequency radar, the high squint mode of airborne terahertz Synthetic Aperture Radar(SAR) can fully exploit its advantages of high-resolution and high-frame-rate, enables high-definition dynamic imaging of the forward squint area and significantly expands the platform's dynamic sensing range. In the broadside mode, terahertz SAR can achieve a larger Doppler bandwidth with a smaller aperture, resulting in relatively small range migration and comparatively simpler imaging processing. However, in the high squint mode, the increase in aperture length and the highly space-variant characteristics of range migration greatly raise the difficulty of motion compensation. To address this issue, this paper investigates high-squint terahertz SAR imaging techniques, employing a joint estimation method using system parameters and echo data to achieve high-precision motion parameter estimation and motion compensation. Based on airborne terahertz radar measured data, high-resolution imaging is achieved at a squint angle of 70°, with a resolution better than 0.2 m. Compared with conventional imaging methods, the proposed imaging algorithm achieves a reduction in Peak Side Lobe Ratio(PSLR) of 16.53 dB and a reduction in image entropy of 39.9%.

Abstract:

Object detection technology enhances the decision-making efficiency of intelligent systems through real-time localization and accurate classification, playing a vital role in traffic monitoring, industrial inspection, and medical image analysis. Heterogeneous image fusion-based detection integrates multimodal data such as Synthetic Aperture Radar(SAR), infrared, and visible images, effectively overcoming single-modality limitations and providing more comprehensive feature representations, thereby achieving superior detection performance. This paper systematically investigates heterogeneous image fusion strategies for object detection and their adaptation to various detection frameworks. Specifically, it introduces fusion strategies at the point, region, feature, and multi-level, analyzes their technical characteristics, and examines their application within single-stage and two-stage detection frameworks along with their respective advantages and limitations. Furthermore, it synthesizes state-of-the-art approaches for joint optimization of fusion and detection. Finally, commonly used datasets and evaluation metrics are presented, along with promising application prospects in intelligent transportation, industrial inspection, and smart healthcare.

Abstract:

To rapidly acquire target position information and achieve high-precision imaging detection of targets in the forward-downward-looking scenario of a flying platform, this paper proposes a real-time imaging algorithm for terahertz-band Synthetic Aperture Radar(SAR) applicable to dive scenarios, based on a forward-downward-looking three-dimensional imaging model under the uniform linear array mode. The algorithm simplifies signal processing through reasonable approximations to reduce computational complexity, thereby enabling rapid three-dimensional scene reconstruction. The feasibility of the algorithm is verified through a simulation platform, and the algorithm is mapped to a high-speed parallel Field-Programmable Gate Array(FPGA) hardware architecture. By comparing the FPGA processing results with the simulation results, the feasibility and real-time performance of the algorithm in an actual hardware system are further validated.

Abstract:

Based on YOLOV8, a specialized algorithm named Synthetic Aperture Radar(SAR)-You Only Look Once(YOLO) is developed for small target detection in SAR images. The proposed architecture incorporates a Pyramid Multi-Scale Feature Aggregation(PMSFA) module, an Efficient Multi-Scale Feature Fusion(FPSConv) module, and a Lightweight Shared Detection Convolutional Head(LSDECD) into the native YOLOV8 framework. The proposed algorithm is validated by using both a self-constructed SAR image small target detection dataset and publicly available datasets. Ablation studies demonstrate the effectiveness of the three introduced modules. Comparative experiments further indicate that the proposed SAR-YOLO algorithm significantly improves small target detection accuracy compared to other object detection methods: the key metric mAP50 is increased by 11.93%, while the detection time per frame is reduced to 18 ms. The proposed algorithm provides a robust, accurate, and real-time detection framework for small target detection in SAR images.

Abstract:

To address the cross-modal registration challenges between Synthetic Aperture Radar(SAR) and optical images, which arise from differences in imaging mechanisms, noise characteristics, and textures—particularly the difficulties in feature extraction from low-texture SAR images, significant domain disparities, and high computational costs of existing methods—this study proposes an improved algorithm named EnhancedXFeat based on the Accelerated Features(XFeat) network. The algorithm enhances the ability to preserve shallow-level details and distinguish deep-level semantics by doubling the number of channels in key modules of the backbone network; introduces a cross-modal dual-branch structure to independently process modality-specific features; and applies a dual attention mechanism twice. These designs effectively resolve the domain difference issue and improve the performance of feature extraction and fusion for low-texture images. Comparative experimental results on a self-constructed dataset demonstrate that EnhancedXFeat outperforms mainstream algorithms significantly: the average number of detected feature points reaches 37.0, which is much higher than 4.3 of Scale-Invariant Feature Transform(SIFT), 6.2 of Oriented FAST and Rotated BRIEF(ORB), and 17.9 of Optical-SAR Match Net(OSMNet); the matching accuracy achieves 88.1%, remarkably superior to 9.2% of SIFT,12.7% of ORB, 68.0% of OSMNet and 68.7% of VGG-16; meanwhile, the single-operation time is controlled to 0.801 2 s, achieving a favorable balance between accuracy and efficiency. The conclusion indicates that EnhancedXFeat effectively improves the accuracy and robustness of SAR-optical image registration through its targeted design, and its lightweight architecture provides an efficient and reliable solution for multi-source remote sensing image registration applications in resource-constrained environments.

Abstract:

The terahertz(THz) band(0.1~10 THz) has become a key technology direction for future wireless communications due to its large bandwidth and high-speed transmission characteristics. In this paper, a 300 GHz terahertz wireless communication system is designed and implemented based on an all-electronics scheme. Compared with photonics-aided approaches, this system offers advantages of simple structure and low complexity. Through the construction of an experimental platform, wireless transmission tests over 50 m are completed. Residual blocks are incorporated into the One-Dimension Convolutional Neural Network(1D-CNN) in the experiments, which can effectively avoid gradient vanishing and enhance signal equalization performance. The effects of transmission rate and different neural network signal recovery schemes on system performance are analyzed in detail. Meanwhile, the relationship among the number of 1D-CNN neurons, the depth of hidden layers, and transmission performance is discussed. The proposed 1D-CNN signal recovery method effectively compensates for nonlinear effects in the system, reducing the system Bit Error Rate(BER) from 4.6×10^-3 to 1.4×10^-3.

Abstract:

As the cornerstone of information technology, the semiconductor industry relies on doping the surface of intrinsic semiconductor wafers as one of its core processes to fabricate high-performance optoelectronic devices and integrated circuits. To improve production efficiency and ensure device quality, there is an urgent need to develop a rapid, non-contact, and non-destructive technique for extracting doping layer thickness and doping concentration parameters. This paper proposes a method that utilizes Fabry-Perot resonance spectroscopy to calculate the doping layer thickness and doping concentration of semiconductor wafers. Based on electromagnetic wave scattering matrix theory, this method enables efficient numerical calculations of the terahertz transmission, reflection, and absorption spectra of semiconductor wafers. By constructing a correlation model between doping layer thickness, doping concentration, and Fabry-Perot resonance spectra, it provides a theoretical foundation for fitting experimental spectra and extracting doping parameters with high precision. This method is expected to offer an efficient, non-destructive detection means for quality control and process optimization in semiconductor manufacturing.

Abstract:

To meet the requirements of miniaturization, low profile, polarization switching, and wide-angle scanning for satellite communication receiving terminals, a novel K-band antenna array is designed. Switchable circular polarization is synthesized in the magneto-electric dipole antenna element through dual linear polarizations. By constructing a double-layer patch, uniformly distributed metallic vias, and "П" shaped orthogonal grounded feeding structure, it attains 20% relative bandwidth with less than -22 dB isolation. The element maintains stable wide-beam radiation patterns across the entire frequency band, exhibiting an Axial Ratio(AR) below 3 dB within ±65° beam coverage. An 8×8 antenna array is constructed by integrating the antenna unit with a multi-stage sequential rotation feeding technique. Simulation results demonstrate that within a scanning range of ±60°, the K-band array achieves a gain exceeding 17.8 dBic and an AR below 3.6 dB, indicating excellent circular polarization beam scanning capability. The antenna array features a compact structure and lightweight design, making it suitable for mobile millimeter-wave satellite communication receiving terminals.

Abstract:

Based on a 0.25 μm GaN High-Electron-Mobility Transistor(HEMT) process platform on SiC substrate, a compact, high-power, high-efficiency Microwave Monolithic Integrated Circuit(MMIC) Power Amplifier(PA) is designed using electro-thermal co-design and microwave device/circuit simulation techniques. Based on output power requirements and load-pull characteristics,the dimensions and optimum impedances of the transistors at each stage are determined. According to the circuit gain requirements, a three-stage cascaded configuration is adopted, with total gate width ratios of 1:3.6:16 for the pre-driver, driver, and final stages, respectively. Through electro-thermal co-design, the die layout is optimized to reduce thermal coupling effects and enhance the heat dissipation capability of the circuit. By employing electromagnetic parasitic parameter extraction technology, a compact circuit layout is achieved with a chip size of 2.7 mm×5.6 mm. Test results demonstrate that the power amplifier achieves a saturated output power greater than 46.5 dBm, a Power-Added Efficiency (PAE) greater than 42%, and a saturated power gain greater than 26.5 dB over the 14~18 GHz frequency band. Owing to its excellent electrical performance, it is suitable for wide applications in communications and electronic countermeasures.

Abstract:

To address the insufficient near-field coupling efficiency in traditional Passive Intermodulation(PIM) test systems, a compact near-field coupling test board operating at 2.6 GHz has been designed and fabricated. The board employs a Substrate-Integrated Waveguide(SIW) architecture and incorporates, for the first time, an adjustable rectangular-slot structure whose dimensions can be optimized to match different materials under test, thereby markedly enhancing the near-field test intensity. While maintaining stable RF electrical performance, the board achieves a high test sensitivity of -170 dBc with a measurement deviation kept within 3 dB. Experimental results demonstrate that the compact geometry is especially suited for evaluating the PIM characteristics of common microscale conductive materials, offering excellent repeatability and stability. The proposed design provides an effective test method for material-level PIM investigations and holds significant value for PIM analysis of components and materials used in mobile-communication systems.

Abstract:

To address the spectrum resource contention issue in heterogeneous wireless networks, a priority-based spectrum interference analysis and adaptive optimization method is proposed. A dual-layer heterogeneous communication system model considering spatiotemporal characteristics is constructed. An interference quantification mechanism integrating time-frequency overlap and Signal-to-Interference Ratio(SIR) evaluation is established, and a weighted interference evaluation model accounting for device priority is proposed. On this basis, a parameter-adaptive Particle Swarm Optimization(PSO) algorithm is designed to achieve dynamic optimal allocation of spectrum resources. Simulation results demonstrate that the proposed method reduces the overall system interference level by an average of 63.3% while ensuring the communication quality of high-priority devices, with the suppression effect on severe interference reaching 81.4%. Compared with existing methods, the proposed approach exhibits significant advantages in both interference suppression and computational efficiency, providing a novel technical solution for spectrum management in complex electromagnetic environments.

Abstract:

Existing track association models are mostly designed for target association tasks in specific scenarios. When target maneuvering patterns become highly variable or the number of targets fluctuates significantly, these models tend to suffer from degraded association accuracy or extensive missed detections. To address the need for real-time perception of track target attributes in multi-target scenarios, this paper proposes a track association model based on multi-scenario threshold switching. The applicable scenarios and limitations of various track association algorithms are analyzed. Simulation verification is conducted to identify the advantageous performance intervals of different track association algorithms under varying scene densities and noise environments, thereby determining environmental thresholds. During practical operation, the track association model with better performance is selected and switched according to current environmental parameters, enabling more accurate and efficient target attribute classification. Experimental results demonstrate that the proposed threshold-switching track association model achieves a comprehensive Correlation Accuracy Rate(CAR) of 98.16%, maintains an association processing time within 1 s for 50 targets, and keeps the comprehensive Missed Detection Rate(MDR) below 17%.

Abstract:

To mitigate the communication interruption problem caused by plasma encountered by hypersonic vehicles, a channel equalization method based on channel prediction is proposed. By investigating the correlation between reflected and transmitted signals, the relationship between transmitted and reflected signals is established; the reflected signal is utilized to predict plasma channel parameters in real time, and corresponding adaptive adjustment strategies are formulated based on the prediction results to counteract the impact of plasma parasitic modulation effects. The phase shift induced by plasma causes special rotation of the constellation diagram for phase-modulated signals, but exerts no significant influence on the main frequency range of frequency-modulated signals; moreover, frequency-modulated signals employ non-coherent demodulation, rendering the phase effect negligible. Consequently, Frequency-Modulated(FM) signals are less affected by plasma. Under the frequency modulation scheme, this paper leverages reflected signals to predict plasma channel characteristics in real time, and compensates for the attenuation caused by plasma parasitic modulation effects on transmitted signals through an adaptive power amplifier at the transmitting modulation stage. Simulation results demonstrate that, compared with non-adaptive modulation schemes, the algorithm adopting adaptive modulation to compensate for channel effects can effectively improve bit error performance.

Abstract:

Effective choice of the solution is essential to achieve a real-time, bi-directional(full- duplex) communication of the smart grid. The Power Line Carrier(PLC) technology provides a low-cost solution, which suits China's own national conditions. In this paper, the advantages of OFDM PLC modulation technology are introduced. A PLC module of system model is established through the analysis of the input impedance under the low-voltage power line channel. The high-speed PLC module based on low-voltage Power Line is also designed according to the studies of power line channel. The results show that the design of the PLC module has featured high receiving sensitivity and anti-noise ability.

Abstract:

With the development of Internet applications, users’ demand for bandwidth is soaring sharply. Meanwhile，along with the development of broadband access technology, the endpoint can also adopt multiple network accesses. But due to one-way communication of traditional Transmission Control Protocol(TCP)，the waste of resources will exist. To this end，IETF has specifically proposed Multi-Path TCP(MPTCP) to implement TCP multiplexing，thereby enhancing the efficiency and robustness. This paper gives a review of the IETF’s research on MPTCP，including MPTCP architecture, routing and congestion control, aiming to provide a reference for deeply studying.

Abstract:

Traditional methods and instruments are not able to measure the true Root Mean Square(RMS) of distortion sine wave or non-sine signal accurately. This article introduces a method to measure the true RMS of any high frequency signal by using the true RMS measurement IC，AD536A，designed by AD corporation. The paper analyses the difference between the RMS measured by the average measure method and the true RMS in theory. It explains the disadvantages of current RMS measure method，and presents the design of true RMS measure circuit. The experiment results prove that the proposed method and circuit can measure the true RMS of any high frequency signal accurately.

Abstract:

Terahertz(THz) optoelectronics has promoted the development of the THz generation, transparent control, and detection methods，and hastened many devices in the past decades. Especially, THz metamaterials and metasurfaces will exhibit extraordinary electromagnetic response when the subwavelength scale metal structure is excited by the THz illumination. Therefore, they have been applied to the devices such as wave beam shaper, waveguide, and modulator etc. The THz metamaterials and metasurfaces also show the potential applications in the research fields such as sensors, communications, and radars. In this paper, the works about the spectrum and wavefront modulation with THz metadevices carried out in our group are summarized. The basic theory and corresponding experiment results for different devices are introduced. It is expected these works can pave the avenue of the application of the THz metadevices.

Abstract:

Aiming at the problems in existing underground personnel positioning systems, an assisted positioning method based on pedestrian dead reckoning is proposed. Low-cost Inertial Measurement Unit(IMU) and magnetometer are employed to constitute a stable Attitude Heading Reference System (AHRS). The theory of inertial navigation is utilized, an algorithm for step detection is described, and Zero velocity Update(ZUPT) is adopted for velocity and position estimation to compose a pedestrian dead reckoning system. An experiment is performed in the corridor of a laboratory building to emulate the underground mine road environment. The experimental results demonstrate that the dead reckoning performs well and this method is an effective complement to existing underground positioning by improving the positioning accuracy.

Abstract:

The requirements for micro stress measurement of strain gauge are high precision，high linearity，high stability and high gain. One kind of differential amplifier circuit with excellent performance was designed. Some skillful techniques were adopted to avoid common voltage in the circuit and to reduce the temperature drift. The gain linearity is about 0.01%，and its Common-Mode Rejection Ratio(CMRR) is about 129 dB under work conditions.

Abstract:

The background requirements of the fuze antenna in terahertz spectrum as well as its advantages and disadvantages are introduced. The working principles and application characteristics of dielectric lens antenna in terahertz frequency are analyzed in order to implement the terahertz fuze antenna. The longitudinal size of H plane horn antenna can be reduced effectively by using fuze antenna formed by an H plane horn with dielectric lens antenna. The terahertz fuze antenna with different beam angles is achieved by focal technology of lens. The feasibility of the technology solution is verified through simulation.

Abstract:

According to the requirements of safe, simple and nondestructive radiation effect investigation of semiconductor devices, the method of laser simulation was proposed and greatly promoted. Compared with large-scale facilities, laser simulation has various unique advantages. It helps understand the ionization radiation effect in depth and is an effective low-cost, table-top supplement for the hardness assurance. Its research shows great significance for radiation effect study in both theory and practice. In this paper, the basic principles of the interactions of γ and laser with semiconductor devices are firstly presented. Then the physical basics and characteristics of laser simulation are given, with the research progress review followed. The existing problems of current research are deeply discussed providing with feasible research approaches. In the end, necessary research contents in the future are proposed.

Abstract:

Ultra-wideband(UWB) communication shows its advantages of fast data transfer(100 Mb/s or above) in a relatively short distance(typically below 10 m) with relatively weak power consumption (energy spectrum below -41.3 dBm/MHz). Integrated with Multiple Input Multiple Output(MIMO) technology, channel capacity could be further enhanced. As a critical link in the ultrawideband communication，UWB antenna needs extra efforts in design optimization to boost the performance of the whole system. UWB antenna is defined as the antenna whose bandwidth exceeds 500 MHz or relative bandwidth greater than 20%. This paper takes the most representative Vivaldi antenna as a show case for multi-objective optimization design with statistical methods. The optimized miniaturized antenna(sized130 mm×100 mm) shows a -10 dB bandwidth of 2.4 GHz. The design method provides guidance in common wideband，multi-parameter antenna design.

Abstract:

Radio Frequency IDentification(RFID) series Radio Frequency(RF) card has been applied widely because of its stability，reliability and easy operation features. Aiming at multiple protocols，such as ISO14443 protocol，ISO15693 protocol and Tag-it protocol，this study proposed a new type of circuit design based on Advanced RISC Machine(ARM) for the RFID series RF card reader. The data stream encryption was implemented by using peripheral device in the operation. The system composition，working principle and work flow were introduced. Then，the detailed circuit design of the RF network and encryption hardware were presented，and the test and analysis for the design were performed. The results showed that the circuit could accurately read, write and encrypt various types of card within effective range.

Abstract:

The design of code tracking loop is a key sector of the realization of noncoherent spectrum spread receiver. In order to realize the code tracking in noncoherent spectrum spread receiver, an energy-normalization digital delay-locked loop was designed, the structure of the loop and the calculating procedure of loop parameters were introduced. The characteristic of noncoherent spectrum spread was analyzed first，and then the key point of the loop design was pointed out. Based on this, the design and realization methods of code loop discriminator, loop filter, early and lag code generator were expatiated. A set of specific loop parameters were introduced as well. Modelsim simulation results and FPGA actual measured data prove the precise code tracking ability of the design.

Abstract:

The application of CORDIC(COordinate Rotation DIgital Computing) arithmetic in solving transcendental function has become popular in modern engineering. A brief introduction of CORDIC arithmetic was given in this study. Taking the hyperbolic sine and cosine functions as examples, the method of realizing the arithmetic in FPGA was presented and simulated on ISE(Integrated Software Environment) platform. The result showed this arithmetic was of good precision and instantaneity because of using pipeline. This arithmetic has great practical value in some applications. In addition, a curve of the relationship between the iterative number and the error obtained by the Matlab simulation of the arithmetic can help designers planning the number of iterations for practical applications.

Abstract:

The implementation of TCP/IP protocol stack on TM320DM642 platform could provide technological support for the application of multimedia embedded systems to networks. Both the function of TM320DM642 chip and the hierarchical structure of LWIP(Light Weight Internet Protocol) were analyzed. Network communications for TM320DM642 systems were implemented by the transplantation of LWIP, not by a solution scheme of NDK(Network Developer’s Kit). Testing examples verified the effectiveness of the LWIP transplanted method.

Abstract:

This article introduces a new type of high speed，multi-modulated digital modulator with adjustable center frequency and bit rate features. It can realize the Quadrature Phase Shift Keying(QPSK) and 16QAM(Quadrature Amplitude Modulation) with 80 MHz center frequency and 7.936 5 MHz bandwidth. The general-purpose modulation arithmetic based on software radio，symbol mapping and the realization of pulse shaping filter are discussed. The measuring results demonstrate that the modulation scheme meets the requirements of practicability and general utilization.

Abstract:

High-speed data acquisition system is an important component in modern radar signal processing. A design of high-speed data acquisition system based on band-pass sampling was presented and applied to the signal processing of wideband receiver. The Virtex Series FPGA was used as the main platform to control the high-speed ADC08D1000 for completing data acquisition, transmission，storage and signal processing. High-speed First Input First Output(FIFOs) were selected as the storage devices to implement data rate conversion. The system realized the software and hardware design，and test results verified the feasibility of the solution.

Abstract:

The Spatial Light Modulation(SLM) technology has been widely applied to the fields of threshold switch, high speed optical interconnection and optical logic operations, which demands good performance on the real-time and fast optical signal addressing. Compared with Electro-Addressing SLM(EA-SLM), Optically-Addressing SLM(OA-SLM) shows great advantages of fast speed and high resolution by parallel addressing. Nevertheless, how to achieve fast and stable optically addressing is the key point in practice. Based on ZnO thin film as a photoconductive layer, Liquid Crystal OASLM(LC-OASLM) is designed and fabricated; the modulation of the readout light intensity and phase distribution in the two-dimensional space is achieved effectively.

Abstract:

The corresponding solutions are proposed to tackle with the disadvantages of conventional oilfield Geographic Information System(GIS), including inconvenience of Client/Server(C/S) mode operation and maintenance, being unable to perform real-time online Point of Interest(POI) rendering, being incapable of segmentation and location according to regions, etc. An oilfield information query system of Browser/Serve(B/S) framework based on AJAX+JSON+HTML5 is designed and implemented. Experimental results show that the POI real-time rendering and regional segmentation improve on their interactivities, and the experiences of users are enriched, which meets the actual requirements of oilfield development. This work has paved the way for the development of diversified network services.

Abstract:

A detector can achieve quick response when it is much smaller than the wavelength of the source signal in THz wave band at the expense of signal coupling capability．Therefore, an antenna is applied to collect signals in order to enhance the signal coupling capability of the detector．The properties of antenna determine the frequency response band，the sensitivity and other parameters of the detector directly. A planar-integrated antenna is adopted for signal acquisition in the Nb5N6 microbolometer detector, which is fabricated by lithography，lift-off and other processes of micro-fabrication. The Nb5N6 microbolometer is placed in the center of the planar antenna. Aiming for the center frequency of 0.32 THz, a special capacitive coupling design is proposed to improve the signal coupling capability．

Abstract:

A double gate setting with priority of Doppler velocity and the Extended Kalman Filter(EKF) based Multiple Hypothesis Tracking(MHT) algorithm are proposed in order to realize Multiple Targets Tracking(MTT) in High Frequency(HF) ground-wave radar, and to effectively improve the performance of MTT by using the Doppler measurement. In the EKF based MHT, parameters obtained in the EKF are adopted directly to calculate the probability of each hypothesis. A simulation scene is built, and the EKF based MHT algorithm is compared with the one which assumes that the Doppler measurement is independent from the radius measurement. Simulation results show that the double gate setting helps induce number of clutter, and the EKF-based MHT algorithm is better than the other one under dense environments of HF ground-wave radar with stronger track-catching and false-alarm-filtering ability and higher efficiency.

Abstract:

The single-channel blind separation of GMSK(Gaussian Minimum Shift Keying) mixing signals is researched. The GMSK mixing signals can not be separated by the Per-Survivor Processing (PSP) algorithm directly, therefore, linear approximation processing of the GMSK signal is considered, which enables GMSK signal to be separated by the PSP algorithm. This algorithm separates the GMSK mixing signals by maximum likelihood estimation in the joint space of the symbol sequential and the channel parameters, reserves the best path and outputs the symbol pairs to get the separated signals. Simulation results show that the bit error rate performance produced by the PSP algorithm on separating the GMSK mixing signals is slightly better than that produced by the particle filtering algorithm; and the complexity of the proposed PSP algorithm is much smaller.

Abstract:

A new usage of Hough Transform is introduced in this paper.Firstly,the position and scope of the license plate is located and the image that contains the license plate is picked up.Then, a two-stage Hough transform algorithm is applied to the image to cal

Abstract:

A forward secure strong proxy signature scheme is proposed on the basis of the proxy signature schemes and forward secure schemes.The security of the proposed scheme relies on the difficulty of solving discrete logarithm problems and the difficulty of com

Abstract:

Wavelet denoising is an important application of wavelet analysis in engineering.The keys of wavelet denoising,namely how to select threshold and how to utilize the threshold to dispose wavelet coefficients,are introduced.Via the noised simulated signal e

Abstract:

Based on three generally accepted basic hypotheses, the definition of environmental factor and restricting conditions of constant failure mechanism are discussed.The research status and common study methods of environmental factor are reviewed. Finally, a

Abstract:

For completing the scheme of hard target smart fuze, several factors influencing the outputting acceleration of the high-G accelerometer such as target material, impact angle, impact velocity, the fixed position of accelerometer, carry plane etc., are put