最新刊期
卷 46 ， 期 9 ， 2018
- 摘要：Inverse synthetic aperture radar (ISAR) imaging for long range small/stealthy target plays an important role in the field of national defense surveillance. However, the performances of the traditional envelop-based range alignment method dramatically degrade due to low signal-to-noise ratio (SNR) of received echo signal, which leads to the inapplicability for the subsequent phase adjustment or azimuth focus. In this paper, a parametric-based approach is proposed to perform joint range alignment and phase adjustment. To that end, translational motion is modeled as multi-component polynomial phase signal (PPS), and inspired by the fact that all the scatterers in the moving target experience the same translational range history, the phase difference (PD) operation and Keystone transform (KT) are utilized to transform the energy of all the scatterers into one range cell. Second, a coherently integrated cubic phase function (CICPF) is developed to focus the energy of all the scatterers onto a peak point, from which the polynomial coefficients can be obtained accurately to realize the translational motion compensation in low SNR environment. Finally, theoretical analysis and experimental results are also provided to validate the effectiveness of the proposed method.关键词：inverse synthetic aperture radar (ISAR);low signal-to-noise ratio (SNR);phase differencing (PD);Keystone transform (KT);coherent integrated cubic phase function (CICPF)444|611|5更新时间：2025-07-16
- 摘要：The SMC (Secure Multiparty Computation) of the location relation between rational numbers and intervals, and that between two rational intervals has been investigated. As an important branch of the confidential scientific computing, this problem was widely applied in database matching, positioning search, etc. However, there still exist many problems, for example, current solutions to the location relation between rational numbers are low efficiency and the research on the location relation between two rational intervals is limited. In order to address the above gaps, firstly, we use polynomials to represent the interval, and convert the problem into determining the scalar product signs of two integer vectors. Thus, the new protocol of the problem between rational number and interval is worked out. Secondly, with the proposed scheme as the basic module, we construct the protocol of the location relation between two rational intervals. Finally, the theoretical analysis and experimental results prove that our protocols are safe and efficient, and we give the application of millionaire problem and computational geometry problem in rational domain.关键词：cryptography;secure multiparty computation;rational number;rational interval;database matching;positioning search;millionaire problem;computation geometry448|463|2更新时间：2025-07-16
- 摘要：Due to the time-varying of the channel and the huge round-trip delay, the application of adaptive coding and modulation (ACM) technique is greatly limited in the mobile satellite environment. In order to solve this problem, an ACM method using partial channel information is proposed based on the characteristics of the line-of-sight component between uplink and downlink, which satisfy the approximate reciprocity in mobile satellite communication. This paper presents an optimized ACM strategy and power allocation method with the constraint of the average transmit power and the average bit error rate, which overcome the limitations of existing adaptation. At the same time, the simulation results also show the effectiveness of the proposed method.关键词：mobile satellite communication;adaptive coding and modulation;shadowed Rice model;transmission delay;partial channel information;spectral efficiency288|250|4更新时间：2025-07-16
- 摘要：Evaporation duct helps in the over-the-horizon operating of the communication, radar systems, etc. at the microwave frequency band. In addition, it causes abnormal blind areas, too. Therefore, the evaporation duct situation acquisition is the key to seize the mastery of the electromagnetic. However, if the density of the sensor is increased to improve the sensing resolution, the cost is high and the improvement is limited. Compressed sensing (CS) provides the theoretical basis for the awareness of evaporation duct, which is recovered from a small number of low speed measurements. The blind adaptive Karhunen-Loéve transform (BAKLT) pursuit is able to fully exploit the sparsity and reconstruct the time and space situation of the evaporation duct. The analysis and simulation demonstrate that the BAKLT evaporation duct situational awareness accuracy is better than that of the control group using discrete cosine transform. The reconstructed result of the proposed method is able to reach the reconstructed SNR level of 30dB saving 90% of the sampling resources, and provides the compression basis for the full time global evaporation duct situation acquisition.关键词：compressed sensing;evaporation duct;principal component analysis;sparse representation;signal reconstruction;reconstruction algorithm;matching pursuit;wireless sensor network164|194|1更新时间：2025-07-16
- 摘要：Stream ciphers based on nonlinear feedback shift register are used in information security of hardware restricted devices such as smart cards, radio frequency identification (RFID) and wireless sensor network. Typical examples of these ciphers are Trivium, Grain v1 and Mickey. Previous algorithms of full diffusion have disadvantages such as few analyzing rounds and indistinct dependent relationship. This paper proposes an algorithm for full diffusion of stream cipher based on nonlinear feedback shift register. The internal states of cipher are represented as linear sets and nonlinear sets. Then round functions of stream cipher are converted to operations of sets. So we can estimate the lower bound of rounds which a stream cipher needs to reach full nonlinear diffusion. Using this algorithm, this paper presents an improved one bit differential distinguisher of Trivium and a real-time attack on full rounds of Trivium-B. Moreover, this method can provide certain theory basis for the design of this kind of stream cipher.关键词：stream cipher;nonlinear feedback shift register;security index of stream ciphers;full diffusion;Trivium;distinguishing attack;divide-and-conquer attack323|439|2更新时间：2025-07-16
- 摘要：Prior works on detection of typosquatting abuse are based on the calculation of edit distance between domains. They do not fully utilize the context information of domains, and usually give many false positive results for short domains. Actively crawling much related information of the given domains can help improving the results, but introduce a heavy overhead. Therefore, we design a lightweight detecting strategy based on domain names, and introduce the bi-directional long short-term memory (LSTM) model to make full use of the domain context information. Furthermore, we give a locality sensitive hashing function for domain names, in order to increase the speed of typosquatting abuse detection over large-scale domain sets. Experimental results on a real data set show that the proposed method can overcome the shortcomings of edit distance based methods, and can detect typosquatting abuse efficiently.关键词：typosquatting domain;edit distance;bi-directional LSTM;context information;locality sensitive hashing271|267|4更新时间：2025-07-16
- 摘要：Object tracking is one of the most important area of computer vision. In order to track the object whose appearance changes dramatically in complex scene, we propose a tracking algorithm based on the convolutional neural network. The network of our tracker has two parts: the feature extraction layer and the adaptive classifier layer. At the beginning, we train a fully-connected layer, a softmax layer and the linear relationship between feature and position of these samples. Next, we define a reliability of the tracking result. If the result is reliable, we will adjust the result location according to its features. Finally, in the network training process, we select the negative samples with max classifying scores in each iteration. The strategy could improve distinguishability of our tracker. Experiments on OTB50 show that our tracker could achieve state-of-the-art performance.关键词：object tracking;neural network;computer vision;machine learning513|871|17更新时间：2025-07-16
- 摘要：In this paper, the closed-form impedance model is provided for an arbitrary orthogonal polyline coil using vertex position-shape description. Firstly, the second order vector potential (SOVP) formula is used for the description of the electromagnetic fields produced by a filamentary rectangular coil. And the scalar potential of the rectangular coil is derived with an integral item described by the position factors and shape factors of the four vertexes of the rectangle. Secondly, two important properties of the shape factors are deduced, with which the analytical expressions of scalar potential can be generalized to the case of arbitrary orthogonal polyline coils. The analytical impedance expressions of arbitrary orthogonal polyline coils are finally derived and applied to a rectangular spiral coil. The theoretical results are compared with the experimental measurements. The comparison results show that the calculated and measured values are in good agreement. The proposed method greatly simplifies the modeling process compared with existing rectangle description method.关键词：impedance model;eddy-current testing;orthogonal polyline coil;second order vector potential;vertex position-shape description168|150|1更新时间：2025-07-16
- 摘要：AEGIS, an authenticated stream cipher, is one of fifteen third-round candidates of CAESAR competition (Competition for Authenticated Encryption: Security, Applicability, and Robustness). Three AEGIS versions: AEGIS-128、AEGIS-256 and AEGIS-128L are recommended in different internal state and key sizes. This paper proposes two types of weak state for AEGIS-256 and AEGIS-128L respectively. The probabilities of these types of weak state are greater than the existing results. And based on those analyses, a forgery attack on AEGIS-256 is introduced. Indeed, we present internal states with the corresponding plaintexts, in which the tags are 0. As for AEGIS-128L, we attain the information leakage of encryption. Finally, we give brief analysis of what is responsible for weak states. To the best of our knowledge, except for design document, there is no cryptanalysis on weak state of AEGIS proposed until now. Therefore, our work is significant for CAESAR competition.关键词：CAESAR;AEGIS;weak states;forgery attack185|245|1更新时间：2025-07-16
- 摘要：Noise are one of the main reasons for biased frequency estimation of ANF (Adaptive Notch Filter). Noise will greatly affect the performance of ANF frequency estimation method under low SNR. When analyzing the ANF statistical performance, some linear approximation methods for ANF transfer function will degrade, the performance of ANF frequency estimation method cannot be evaluated precisely. So the noise statistical performances of mean and variance after different transform are analyzed by using correlation function and power spectrum method. Noise statistical performance results are used for performance analysis of ANF frequency estimation method, meanwhile a theoretical analysis foundation is established to improve the accuracy of ANF frequency estimation method. The performances of ANF frequency estimation method are compared by the theoretical values and the actual values, which show the effectiveness of the noise analysis method, and the steady-state performance of frequency estimation can be estimated approximately.关键词：sinusoidal signal;Noise analysis;adaptive notch filter;frequency estimation167|208|1更新时间：2025-07-16
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Sampling-Precision-Switching-Based Idle Listening Scheme for Millimeter-Wave Wireless Communications
摘要：In this paper, a novel energy-efficiency sampling-precision-switching-based idle listening scheme is proposed for millimeter-wave wireless communications to achieve the target that the power consumption of idle listening is irrelevant to that of the energy-consuming analog-to-digital converter (ADC) required by the demodulation of receiver. To be more specific, in the idle listening phase, the receiver enables ultra-low power 1-bit ADC as well as the proposed 1-bit-sampling-precision generalized likelihood ratio test (GLRT) detector to capture the arrival of data packet; once capturing it successfully, the receiver switches to an original high-precision ADC and demodulate this packet, which maintains the demodulation performance. Meanwhile, the false-alarm probability (FAP) and miss-detection probability (MDP) expressions of the packet detector of the proposed scheme are derived and subsequently validated. Simulation results show that the proposed scheme can significantly reduce the power consumption of idle listening and obtains the effective packet-detection performance, compared with the existing schemes.关键词：millimeter-wave wireless communications;idle listening;packet-arrival detection;generalized likelihood ratio test (GLRT);energy-efficiency186|181|0更新时间：2025-07-16 - 摘要：In mobile social networks, in order to ensure the privacy of users in the process of friend matching, a privacy protection scheme for multiple keys is proposed. Proxy re-encryption technology is utilized to encrypt the user's key into ciphertext, expand friend matching access policy conditions and ensure no leakage of the ciphertext of user privacy during the process of transformation. The employed encryption technology of random ciphertext components can realize the hidden information of the plainntext, and improve the crack difficulty of the attacker. Multiple encrypted files decryption problem is solved by data signature technology, which are not considered by previous works. Security and experimental analysis show that this scheme can achieve CPA (Chosen Plaintext Attack) security, ensure the privacy of friend discovery, and that is more effective than existing solutions.关键词：multi-key confusion;proxy re-encryption;data signature;privacy-preserving191|211|0更新时间：2025-07-16
- 摘要：The scalar multiplication algorithms for non-supersingular elliptic curves have been widely studied. In contrast, the endomorphism ring of supersingular elliptic curve is an order in a definite quaternion algebra, which is not commutative. This paper focuses on a class of supersingular elliptic curves of j-invariant zero in characteristic greater than 3. We make analysis of the structures of its endomorphism ring and quotient ring. Further we study the properties of integer expansion according to this class of curves. Based on this representation, a scalar multiplication algorithm is proposed. We demonstrate that the representation is essentially the p-adic expansion in theory when a suitable digit set is chosen. The experimental results show that compared with the method of 4-NAF, the p-adic method improves the efficiency of scalar multiplication of more than 100%.关键词：supersingular elliptic curve;quaternion algebra;endomorphism ring;Frobenius endomorphism;τ-adic expansion132|138|0更新时间：2025-07-16
- 摘要：Counting triangles in a graph is an important step to calculate the clustering coefficient and the transitivity ratio of the network. Under the background of big data, the sampling method is the main method used in triangle counting. However, two problems of spatiotemporal costs and computing errors are very difficult. An approximate triangle counting algorithm based on Markov chain in the graph stream is proposed. Treating the window as processing unit of graph stream, it uses Markov chain to implement dynamic adaptation of memory and to reduce error ratio while sampling. Compared with other algorithms, the proposed algorithm can drop the error rate by 2~4 times, and the time consumption has a great improvement.关键词：triangle;graph streaming;Markov chain;big data;Spark154|142|1更新时间：2025-07-16
- 摘要：The dual-band predistortion models suffer from high complexity and non-adaptability of optimization algorithms. To address this issue, this paper proposes an adaptive optimization algorithm for dual-band predistortion model with reduced complexity. We use dual-band general memory polynomial (DB-GMP) as the predistortion model where all basis function terms of the original DB-GMP model are sorted by orthogonal matching pursuit algorithm. In each iteration, all selected basis function terms help to construct an alternative model. We then derive the Bayesian information criterion (BIC) when output vector elements of the DB-GMP model are with non-independent identical distributions, and the model with smallest BIC value is treated as the optimized model. Finally, we achieve the proposed algorithm without the information of model sparsity and fitting error threshold. Simulation results show that compared with the original DB-GMP model, the coefficient number of the optimized model is reduced by more than 75%, while both the models after predistortion have almost the same level of adjacent channel power ratio and normalized mean squared error, leading to good predistortion performance.关键词：power amplifier;predistortion;sparsity;orthogonal matching pursuit;Bayesian information criterion86|180|2更新时间：2025-07-16
- 摘要：GF-3 is the first quad-polarized spaceborne SAR (Synthetic Aperture Radar) of China and it is one of the most advanced quad-polarized spaceborne SARs. In-orbit calibration is very essential for reliably and quantitatively measuring, and system calibration has been performed during the first three months since launch. A design concept of quad-polarized transponder is proposed. Based on the data obtained using the novel quad-polarized transponders developed for GF-3 during the calibration campaign, this paper analyzes some performances of GF-3 SAR such as the azimuth antenna pattern, the characteristic of SAR pulse and the polarization isolation in azimuth. The analysis result shows that the performances of GF-3 are quite well. Furthermore, the performances of the transponders are validated using the quad-polarized image result. It is proved that the transponders not only can provide various types of scattering matrix but also have a perfect performance of reference point target and the polarization isolation.关键词：GF-3;SAR;transponder;polarimetric calibration131|221|1更新时间：2025-07-16
- 摘要：Ad hoc opportunistic communication has become a hotspot with the popularity of various mobile multimedia intelligent terminals. However, the opportunistic communication style among mobile nodes cannot satisfy the growing of multimedia transmission. Aiming to the issues of opportunistic networking and video content transmission, based on the opportunistic network communication capability calculation, we proposed a method of calculating the optimal size of video fragment. The method could maximize the use of network communication capabilities. After that, a video routing and scheduling algorithm is proposed to receive video fragments progressively, and to create fragment priority model which results to uniform fragments distribution at destination node. The experimental results show that the proposed methods can make efficient video content preview and transmission in challenging communication environment, and can support the related video content transmission in wireless mobile environment.关键词：opportunistic networks;fragment transmission;scheduling algorithm114|162|2更新时间：2025-07-16
- 摘要：A novel method to construct rotation symmetric resilient functions with q variables is proposed over GF(p) by using a Latin square with maximum cycle structure. This method is based on the equivalence between resilient functions and Large sets of orthogonal arrays. Additionally, an example is given to demonstrate that some rotation symmetric resilient functions with q variables can be constructed by the method presented in this paper, while these functions cannot be determined according to the earlier constructions over the finite field GF(p).关键词：cryptography;rotation symmetric functions;balanced functions;resilient functions;l-value support table158|156|0更新时间：2025-07-16
- 摘要：In through-the-wall imaging (TWI), the target image is often buried in the reflections of the wall and other clutter waves, and the target image cannot be obtained. The subspace technique has an impact on the target information when the clutter is suppressed. This paper presents the delay lock loop tracking-and-subtraction method to mitigate the clutter in TWI, and the time delay of the wall echo and direct wave is estimated and eliminated. It is widely used in the disaster rescue, hostage rescue, and city street battle. The results, compared with the average elimination method and subspace method, show that the proposed method can effectively suppress the clutter. The improvement factor (IF) of the target image is enhanced and the excellent target image is obtained.关键词：through-the-wall imaging (TWI);target detection;clutter mitigation;delay lock loop (DLL);Signal reconstruction;Improvement factor256|190|0更新时间：2025-07-16
- 摘要：There are the characters of large data, strong effectiveness and complex environment in a single-frame image of illegal encroaching vehicles, the detection of illegal encroaching vehicles requires amount of experimental work and labor. In the process of positioning license plates, people cannot avoid some interference such as experience, fatigue, which results in missing and misplacing license plates. The computer-assisted location algorithm of license plates is proposed from the perspective of visual perception, and used the method of multiple scales in this paper. Simulating the visual perception principle, the computer successively focused to the license plate area according to vehicle characteristics, texture features, and color characteristics scale. We put forward a complete license plate positioning process for the single-frame image and propose an accurate location algorithm for license plate area based on boundary pair. The experiments on real traffic images show that the proposed algorithm has a higher accuracy rate when the image is acquired from the head or rear of vehicles, and is consistent with the process of human visual perception, and can detect multiple license plates on the single image at the same time. But further study need to be carried in the situation of too dark environment, too bright light or color distortion.关键词：computer assisted location;visual perception;license plate;multi-scale;boundary pair121|272|5更新时间：2025-07-16
- 摘要：Over a power-limited additive white Gaussian noise channel (AWGN), the transmission performance can achieve the channel capacity when the input follows Gaussian distribution. Therefore, this paper found a promising ununiform-APSK (Amplitude Phase Shift Keying) constellation mapping "4+12F-APSK" which is optimized by the binary switching algorithm (BSA) using Harmonic mean after feedback to be the cost function, and presented a joint demodulation and decoding method based on high-performance code-modulation mapping to approach the channel capacity efficiently. In BICM-ID (Bit Interleaved Coded Modulation-Iterative Decoding), simulation results show that, in Rayleigh fading channel at BER (Bit Error Rate) of ten to the negative five, the proposed method outperforms the traditional rectangle 16QAM (Quadrature Amplitude Modulation) mapping as MESW (Maximum Squared Euclidean Weight), GRAY and SP (Set Partitioning) by 0.6dB at least; in AWGN channel at BER of ten to the negative three, this number is 0.3dB compared with MSEW and GRAY mapping. Moreover, both in Rayleigh and AWGN channels, the proposed method has 1dB~2dB performance gain compared with the other ununiform-16APSK mappings. It has a wide range of applications in resource limited networks such as mobile and broadcast communication.关键词：non-uniformly spaced APSK constellation;mapping optimization;BICM-ID;joint demodulation and decoding116|194|3更新时间：2025-07-16
- 摘要：In this paper, we design a topic-features lattices analysis (TFLA) framework based on objectivity quality dimensions. Firstly, we apply the latent Dirichlet allocation (LDA) approach to get latent topics as topic-features for each goods categories. Secondly, we construct formal background based on the strong relationship between goods categories and topic-features. So we could get generalization and instantiation relationship among the topic-features through formal concept analysis (FCA). We employ domain knowledge and relationships among topic-features to define five objective quality features. Also, we use machine learning methods to build quality evaluation models based on these quality features. Experiment results on actual comment data sets show that our new quality models' prediction results are in agreement with the artificial quality tags in most cases. The best performances could get that the mean absolute error (MAE) is 0.7 and F-measure is 0.5, which is significantly better than the conventional quality prediction model based on support vector machine (SVM) classification.关键词：user comment;data quality;topic features;lattices of topic-features158|415|2更新时间：2025-07-16
- 摘要：In this paper we analyse multiple factors which affect system service time allocation decision, and propose a network coding multi-dimension feature definition model of weight based service time allocation mechanism (FDMW). FDMW construct multi-dimension feature definition model, and adjust system service time allocation decision adeptly. Simulation shows FDMW can optimize system service and promote system efficiency.关键词：network coding;service time;weight103|159|1更新时间：2025-07-16
- 摘要：To improve the tracking accuracy of hypersonic jumping gliding target in near space, a new type of maneuvering tracking model with second order time correlation is put forward based on the characteristic analysis of near space hypersonic vehicle target motion, the key of the model is to model target's acceleration as a zero mean random process with attenuation oscillation autocorrelation, and the state equation of tracking the near space hypersonic jumping gliding target is built; in order to further analyze the adaptability of the model, the system dynamic error steady state value of the model is deduced by combining the Kalman filtering algorithm, and the adaptability of the model is discussed from the point of the model parameters; then the relationship between the two parameters in the model is analyzed to improve the rationality of the model parameters, and the approximate reference interval of the parameters are given. The theoretical analysis shows that the model has the unity of periodicity and attenuation, which is mainly expressed as periodic in a short time, and mainly expressed as exponential decay in a long time, these feature improves the rationality of the description of the motion of near space hypersonic jumping gliding target, in addition, the model has a low system dynamic error steady state value when the theoretical value of the model parameters in tracking the near space hypersonic jumping gliding target are obtained. Simulation results show that the model has a higher tracking accuracy when compared with the existing single noise maneuvering model of the near space hypersonic target; and the rationality of the method of parameterization is explained by comparing the simulation results under different parameters.关键词：near space;hypersonic vehicle;target tracking;maneuvering model;Kalman filtering;system dynamic error139|228|3更新时间：2025-07-16
- 摘要：In the network attack-defense game systems, there are many stochastic factors, such as changes of attack-defense strategy sets and system operating environment. The traditional deterministic game model can not describe the game process of network attack and defense accurately. This paper constructed an attack-defense stochastic evolutionary game model by adapting the nonlinear Itó stochastic differential equations. The model can be applied to analyze the stochastic evolutionary process of network attack and defense. In addition, the stability of the strategy selection of attack and defense was analyzed according to the discriminant theorem of stochastic differential equations. Besides, an algorithm to select the security defense strategies based on stochastic attack-defense evolutionary game model was designed. Finally, the simulations demonstrate that the different intensity influences of stochastic interference on the speed of decision-making evolution of attack and defense. The attackers and defenders are more inclined to choose strong strategies when the game system has great intensity of interference. The model and the method proposed in this paper can provide guidance for attack behavior prediction and defense strategy selection.关键词：network security;network attack-defense;game theory;bounded rationality;evolutionary game;network defense;Itóstochastic differential equation;strategy selection234|291|11更新时间：2025-07-16
- 摘要：With the introduction of network functional virtualization (NFV), operators can provide more flexible services based on general computing and network platforms. This paper investigates the problem of migration and re-deployment of service function chain (SFC) in NFV based operator network. Firstly, this paper analyzes the problem of resource under-utilization and load unbalance in the operator network caused by the dynamic of the flow. Then, based on the consideration of the conditions such as computing resources, network resources and end-to-end restrictions, the mathematical model towards the service delay optimization is formulated, and the NP property of SFC migration and re-deployment problem is proved. Furthermore, a heuristic SFC migration and re-deployment policy is proposed based on genetic algorithm. In-depth experimental result demonstrates that the proposed solution is superior to other solutions in terms of end-to-end delay, the utilization ratio of link bandwidth resource and the utilization ratio of general server by 12.3%, 10.9%, and 15.8%. The results further shows that the resource utilization is effectively improved in the case of guaranteeing the quality of service for flow, through the reasonable deployment of operator network resources.关键词：network function visualization;service function chain;operator network;genetic algorithm181|185|8更新时间：2025-07-16
- 摘要：In radio frequency powered wireless sensor network (RFP-WSN), improving network energy efficiency and throughput is an important topic. A data collection scheme with high energy-efficiency and high throughput is proposed in this paper, which integrates channel allocation, energy threshold and MAC (Medium Access Control) frame block-level retransmission mechanism. In addition, the charging time of nodes, the average energy consumption and the average delay for transmitting a MAC frame, and the energy efficiency and throughput of the network are derived. The network utility function is defined, and the optimization problem (OP) of maximizing network utility is formed. By adjusting the utility coefficient and solving the OP, the optimal energy threshold and the optimal number of blocks per MAC frame can be obtained to maximize the energy efficiency and throughput. The simulation results show that the energy efficiency and throughput of the proposed scheme are higher than that of the existing schemes.关键词：radio-frequency powered communications network;wireless sensor network;data collection;throughput;energy efficiency190|261|0更新时间：2025-07-16
- 摘要：The existing security methods in the cloud such as encryption, access control, and VM isolation can not guarantee end-to-end data security. To address this problem, a double-layer information flow control model is proposed. The definition of key element, centralized and decentralized information flow rules, capability adjustment rules, label propagation rules, and declassification rules of the model are presented. Then, taking the advantages of dynamic taint tracking and virtual machine introspection technologies, a prototype system named IFCloud are designed and implemented. IFCloud achieves information flow tracking and controlling as a service for cloud tenant and provides detection methods against common system attacks such as stack and buffer overflow attack for the cloud provider. Finally, IFCloud is demonstrated to be a flexible and accurate system that tracks and controls the sensitive data flow in the cloud at runtime from the function test results, and it can be applied to protect data security at a fine-grained level for the software as a service cloud.关键词：cloud data security;information flow control model;dynamic taint tracking;virtual machine introspection;stack overflow attack269|179|2更新时间：2025-07-16
- 摘要：This paper presents a set of test methods of analog to digital converter (ADC) dynamic performance, which are used for ADC with high sample rate and large bandwidth in next generation optical transmission system. Based on the analysis of the characteristics of ADC in optical transmission, the following essential problems are solved, including measuring the frequency of sampling clock directly, gathering the output data, calculating the resolution, and correcting the nonlinear error of bandwidth testing. The methods are used in performance evaluation on ultra-high speed ADCs, which are used for high data rate applications, such as optical transmission, radar, satellite, etc. Based on the test results, these methods have solved the key problem of 70GSPS sampling rate 16GHz bandwidth high speed ADC, which can meet the requirement of ADC dynamic performance test used in next generation 400Gbps optical transmission.关键词：ultra-high speed analog to digital converter;next generation optical transmission system;gain compensation;insertion loss cancellation258|329|0更新时间：2025-07-16
- 摘要：In recent years, the study of image super-resolution reconstruction technology has been paid much attention to, because it can improve image recognition accuracy and recognition ability. One of the difficult problems is how to ensure the reconstruction quality of image edge texture area. In this paper, a single image super-resolution reconstruction approach based on wavelet domain is proposed. Firstly, the non-subsampled wavelet transform (NSWT) is applied to the input image, according to the multi-directionality of wavelet transform, three kinds of multi-angle templates are proposed, and each subband contour is estimated by total variation model (TV model) to determine its optimal direction. Then, the multi-angle templates and bicubic B-spline interpolation are used to interpolate the subbands. Finally, the non-subsampled wavelet inverse transform is implemented. This approach makes edge information and texture information of the reconstructed images more precise, and overcomes some deficiencies such as edge blurring, edge serration, as well as distortion of texture region, caused by traditional interpolation reconstruction approaches, such as bilinear interpolation and bicubic interpolation, etc. The quality of reconstructed image is improved. This approach can be used in image monitoring, remote sensing image analysis, medical image processing, and so on. A large number of simulation experiments verify the effectiveness of the proposed approach.关键词：non-subsampled wavelet transform;contour template;variational calculus model;directional interpolation;super-resolution reconstruction;Edge;high-frequency subbands;multi-angle;template matrix310|321|7更新时间：2025-07-16
- 摘要：To determine the population size of multi-objective particle swarm optimization algorithm (MOPSO), an improved MOPSO, based on the convergence speed and diversity, named CD-MOPSO, is proposed. Firstly, the fitness function of population size, which is developed by the convergence speed and diversity during the evolutionary process, is used to describe the relationship between the population size and the performance of MOPSO. Secondly, according to the fitness function, an adaptive adjustment method is designed to update the population size of MOPSO dynamically. Finally, the proposed CD-MOPSO is tested on the ZDT benchmark optimization problems and applied to a real optimization problem of urban pipe networks. The experimental results show that the proposed CD-MOPSO can adjust the population size automatically according to the problem, compared with the performance of NSGA, MOPSO, SPEA2 and EMDS-MOPSO, CD-MOPSO has faster convergence speed with better optimization results.关键词：multi-objective particle swarm optimization algorithm (MOPSO);population size;adaptive adjustment method;dynamic adjustment;fitness function;convergence speed;diversity;benchmark test functions;urban pipe networks optimization354|345|1更新时间：2025-07-16
- 摘要：Based on the concept of diversity gain, MIMO (Multiple Input Multiple Output) radar has obvious advantages over phased array radar in target detection, parameter estimation, multi-target discrimination and interference identification and suppression. Angle estimation is the core of parameter estimation and also the prerequisite for radar to locate and track spatial targets. A high-resolution and low computational complexity 2-D DOD (Two Dimensional Direction-of-Departure) and 2-D DOA (Two Dimensional Direction-of-Arrival) estimation algorithm based on double L-shaped arrays for bistatic MIMO radar is presented. By performing the eigen-decomposition of the matched array data, the array manifold can be estimated. Furthermore, we can obtain the closed-form solution of the 2-D DOD and 2-D DOA. The proposed method has similar estimation performance with 2-D ESPRIT (Two Dimensional Estimating Signal Parameters via Rotational Invariance Techniques) and the computational complexity is about one third of it. The estimated 2-D DOD and 2-D DOA could be paired automatically. Numerical simulation results show that the proposed method achieves a high-precision four dimensional angle estimation with low computational complexity.关键词：phased array radar;MIMO radar;target detection;parameter estimation;2-D DOD;2-D DOA;double L-shaped arrays236|177|2更新时间：2025-07-16
- 摘要：When subjected to flexing, conventional metallic structures can crease, fatigue, and eventually fail mechanically with a catastrophic loss of conductivity and functionality. A flexible frequency reconfigurable coplanar waveguide-fed (CPW) antenna consisting of four split-ring resonators (SRRs) with different radii is presented to solve the problem. The SU-8 negative mold structure is fabricated with microfluidic channel by ultraviolet lithography (UV lithography), and then the PDMS (PolyDiMethylSiloxane) is used to cast for the SU-8 microfluidic to obtain a PDMS positive mold structure. Finally, the liquid metal alloy was injected into the microfluidic channels of PDMS. Changing the pass state of the SRRs by mechanical pressure, the antenna can be reconstructed at multiple frequencies within the range of 1GHz~6GHz. The proposed antenna can meet the communication requirement of WLAN, Wi-MAX and C-band. The combined properties of the fluid and the elastomeric substrate result in a flexible and durable antenna that is well suited for simple means of integrating electronic devices on curved surfaces, such as wearable devices and artificial skins.关键词：flexible liquid metal antenna;coplanar waveguide (CPW);split-ring resonators (SRR);ultraviolet lithography;polydimethylsiloxane (PDMS);frequency reconfigurable;WLAN/WiMAX;curved surfaces195|285|0更新时间：2025-07-16
- 摘要：Compared with classical electromagnetic (EM) waves, the vortex electromagnetic wave carrying orbital angular momentum (OAM) has higher dimensional information-modulation freedom, which paves the way to the OAM's applications in radar target detection and imaging. Firstly, the concept of vortex EM wave and the radiation field in linear polarization are introduced. Subsequently, the principles of the vortex-EM-wave-based radar imaging and detection are presented. The advantages over traditional radar detection technology are analyzed and elaborated. Moreover, the development history and research actuality of the EM vortex imaging and the rotational Doppler frequency detection are overviewed. Especially, the generation technique of vortex EM waves for radar detection purposes is summarized. Finally, by viewing the prospects for the applications of vortex EM waves, some scientific problems in the development of vortex-EM-wave-based radar are proposed.关键词：vortex electromagnetic wave;orbital angular momentum;novel radar paradigm;electromagnetic vortex imaging;rotational Doppler detection439|649|8更新时间：2025-07-16
- 摘要：Uniform circular array (UCA) can generate vortex wave with orbital angular momentum (OAM) in microwave band, this paper studies the effects of the coupling among the units on the OAM modes. The effects are evaluated by analysis and numerical computation based on momentum method (MoM). The results show that, if the coupling among units is rotational symmetry, then the coupling will not affect the generation of the OAM-carrying vortex wave. But if the coupling among units is not rotational symmetry, then the coupling will affect it. The effects is influenced by the mode number, the radius of the UCA, and the azimuth location of the field. Based on the characteristics used in the paper, even if the distance between the neighboring units is larger than two wavelengths, the mode number can be changed by more than 14%. It is significant for UCA design for vortex wave generation.关键词：vortex wave;orbital angular momentum (OAM);uniform circular array (UCA);coupling128|181|0更新时间：2025-07-16
- 摘要：A single-phase full-bridge soft-switching inverter with passive device-assisted commutation is proposed to improve conversion efficiency of the single-phase full-bridge inverter. The soft-switching action of the switch devices is achieved by adding an auxiliary resonant circuit to bridge arms of the inverter. There is no auxiliary switch device in the auxiliary resonant circuit but few passive devices such as inductances, capacitances, diodes, and so on, which is helpful to reduce the cost of the auxiliary circuit and can't complicate the control strategy of the inverter. In addition, freewheeling of load current can be realized via the auxiliary circuit and the distortion ratio of output current waveforms of the inverter is reduced when the inverter is in the dead state, which reduces the effect of dead-time on the output current of the inverter. The operation process of the circuit is analyzed in detail. The experimental verification is carried out on a 4kW one-phase laboratory prototype. Experimental results verify that the switch devices of the inverter can achieve soft-switching in both light load and full load, the distortion ratio of output current waveforms of the inverter is improved. Therefore, the single-phase full-bridge soft-switching topology with passive device-assisted commutation has an important significance for improving the performance of inverter.关键词：inverter;passive;soft-switching;dead-time;switching loss169|134|7更新时间：2025-07-16
- 摘要：In order to establish the mathematical integration model of the pyroelectric infrared (PIR) sensor mechanism and the characteristics of human body thermal radiation and understand the relationship on PIR sensor between the human body thermal radiation and induction and the human characteristics, this paper studied the working principle of the PIR sensor and the laws of mobile body induction in the PIR sensing regions. The mapping relationship between human characteristics and mechanism of PIR sensing is deduced, which reveals the intrinsic logical connection between induction data and the human radiation source and PIR sensors characteristics. The experimental data show that the higher the human body radiation temperature is, the greater the radiation energy per unit area and the detected voltage amplitude will be; the faster the velocity is, the smaller the detected voltage amplitude will be; the bigger the human body is, the larger the detected voltage amplitude and the radiation area will be. At the same time, the experimental results also verify the correctness and validity of the proposed mathematical model.关键词：PIR (pyroelectric infrared radial) sensor;principle of pyroelectricsensing;sensing model;pyroelectric characteristics of human body94|172|0更新时间：2025-07-16
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