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Uncertainty propagation analysis by an extended sparse grid technique
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作者 X.Y.JIA C.JIANG +3 位作者 C.M.FU B.Y.NI C.S.WANG M.H.PING 《机械工程前沿:英文版》 CSCD 2019年第1期33-46,共14页
In this paper,an uncertainty propagation analysis method is developed based on an extended sparse grid technique and maximum entropy principle,aiming at improving the solving accuracy of the high-order moments and hen... In this paper,an uncertainty propagation analysis method is developed based on an extended sparse grid technique and maximum entropy principle,aiming at improving the solving accuracy of the high-order moments and hence the fitting accuracy of the probability density function(PDF)of the system response.The proposed method incorporates the extended Gauss integration into the uncertainty propagation analysis.Moreover,assisted by the Rosenblatt transformation,the various types of extended integration points are transformed into the extended Gauss-Hermite integration points,which makes the method suitable for any type of continuous distribution.Subsequently,within the sparse grid numerical integration framework,the statistical moments of the system response are obtained based on the transformed points.Furthermore,based on the maximum entropy principle,the obtained first four-order statistical moments are used to fit the PDF of the system response.Finally,three numerical examples are investigated to demonstrate the effectiveness of the proposed method,which includes two mathematical problems with explicit expressions and an engineering application with a black-box model. 展开更多
关键词 uncertainty propagation ANALYSIS EXTENDED SPARSE grid maximum entropy principle EXTENDED GAUSS integration Rosenblatt transformation HIGH-ORDER MOMENTS ANALYSIS
Management of pancreatic head adenocarcinoma: From where to where? 预览
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作者 Kemal Dolay Fatma Umit Malya Sami Akbulut 《世界胃肠外科杂志:英文版(电子版)》 2019年第3期143-154,共12页
Pancreatic head adenocarcinoma (PHAC) is one of the most aggressive malignancies, and it has low long-term survival rates. Surgery is the only option for long-term survival. The difficulties associated with PHAC inclu... Pancreatic head adenocarcinoma (PHAC) is one of the most aggressive malignancies, and it has low long-term survival rates. Surgery is the only option for long-term survival. The difficulties associated with PHAC include higher frequencies of regional or distant lymph node metastases and vascular involvement, and positive resection margins in pancreatic and retroperitoneal tissues. Radical resections increase margin negativity and life expectancy;however, the extend of the surgery applied is controversial. Thus, western and eastern centers may use different approaches. Multiorgan, peripancreatic nerve plexus, and vascular resections have been discussed in relation to radical surgery for pancreatic cancer as have the roles of neoadjuvant and adjuvant therapy regimens. Determining the appropriate limits for surgery, standardizing definitions and surgical techniques according to guidelines, and centralizing pancreatic surgery within high-volume institutions to reduce mortality and morbidity rates are among the most important issues to consider. In this review, we evaluate the basic concepts underlying and the roles of radical surgery for PHAC, and lymphadenectomy, nerve plexus, retroperitoneal tissue, vascular, and multivisceral resections, total pancreatectomy, and liver metastases are discussed. 展开更多
关键词 PANCREATIC head cancer Standard PANCREATECTOMY EXTENDED PANCREATECTOMY Regional LYMPHADENECTOMY EXTENDED LYMPHADENECTOMY
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A two-density approach to the general many-body problem and a proof of principle for small atoms and molecules
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作者 Thomas Pope Werner Hofer 《物理学前沿:英文版》 SCIE CSCD 2019年第2期89-96,共8页
An extended electron model fully recovers many of the experimental results of quantum mechanics while it avoids many of the pitfalls and remains generally free of paradoxes. The formulation of the manybody electronic ... An extended electron model fully recovers many of the experimental results of quantum mechanics while it avoids many of the pitfalls and remains generally free of paradoxes. The formulation of the manybody electronic problem here resembles the Kohn Sham formulation of standard density functional theory. However, rather than referring electronic properties to a large set of single electron orbitals, the extended electron model uses only mass density and field components, leading to a substantial increase in computational efficiency. To date, the Hohenberg-Kohn theorems have not been proved for a model of this type, nor has a universal energy functional been presented. In this paper, we address these problems and show that the Hohenberg Kohn theorems do also hold for a density model of this type. We then present a proof^of^concept practical implementation of this method and show that it reproduces the accuracy of more widely used methods on a test-set of small atomic systems, thus paving the way for the development of fast, efficient and accurate codes on this basis. 展开更多
关键词 MANY-BODY condensed matter HARTREE-FOCK DENSITY functional theory extended ELECTRONS
Experimental Evaluation of A New Developed Algorithm for An Autonomous Surface Vehicle and Comparison with Simulink Results 预览
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作者 Hossein MOUSAZADEH Ali KIAPEY 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第3期268-278,共11页
Performing repeatable duties automatically was the dreams of human being for centuries. Although full autonomy has long been dreamed of by visionaries, many researches have been performed for surface vehicles automati... Performing repeatable duties automatically was the dreams of human being for centuries. Although full autonomy has long been dreamed of by visionaries, many researches have been performed for surface vehicles automation since the last century to get close to this dream stepwise. To increase daily working hours and accuracy and reduce cost, operations such as hydrography are susceptible for autonomy. Beside platform topology, installed sensors and energy resources, the core elements of any autonomous surface vehicle are navigation, guidance and control systems. To perform bathymetry operation in autonomy manner, a reliable and robust navigation algorithm is designed and embedded in an autonomous surface vehicle titled Morvarid. Morvarid is a plug-in hybrid solar powered catamaran boat. The developed algorithm is a combination of extended Kalman filter, search ball and potential field approaches. Many experimental field tests are carried out after simulation in Simulink environment. Test results illustrated the algorithm and improved the path followed by reducing SD and RMSE and there is a good correlation between simulation run and experimental tests. 展开更多
关键词 AUTONOMOUS surface vehicle extended KALMAN filter SEARCH ball TRAJECTORY tracking BATHYMETRY
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Extended Fisher-Kolmogorov系统在Direchlet边界条件下的定态分歧 预览
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作者 王英霞 侯芊如 潘志刚 《应用数学进展》 2019年第6期1114-1120,共7页
本文研究了Extended Fisher-Kolmogorov系统在Direchlet边界条件下的分歧问题,利用规范化的Lyapunov-Schmidt约化方法,通过谱分析以及分歧理论,证明了分歧解的存在性并得到了其完整表达式,最后对分歧解的正则性进行了讨论。
关键词 EXTENDED Fisher-Kolmogorov系统 Direchlet边界 Lyapunov-Schmidt约化 分歧解 正则性
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A model-based prognostics method for fatigue crack growth in fuselage panels
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作者 Yiwei WANG Christian GOGU +2 位作者 Nicolas BINAUD Christian BES Jian FU 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第2期396-408,共13页
This paper proposes a model-based prognostics method that couples the Extended Kalman Filter(EKF) and a new developed linearization method. The proposed prognostics method is developed in the context of fatigue crack ... This paper proposes a model-based prognostics method that couples the Extended Kalman Filter(EKF) and a new developed linearization method. The proposed prognostics method is developed in the context of fatigue crack propagation in fuselage panels where the model parameters are unknown and the crack propagation is affected by different types of uncertainties. The coupled method is composed of two steps. The first step employs EKF to estimate the unknown model parameters and the current damage state. In the second step, the proposed efficient linearization method is applied to compute analytically the statistical distribution of the damage evolution path in some future time. A numerical case study is implemented to evaluate the performance of the proposed method. The results show that the coupled EKF-linearization method provides satisfactory results: the EKF algorithm well identifies the model parameters, and the linearization method gives comparable prediction results to Monte Carlo(MC) method while leading to very significant computational cost saving. The proposed prognostics method for fatigue crack growth can be used for developing predictive maintenance strategy for an aircraft fleet, in which case, the computational cost saving is significantly meaningful. 展开更多
关键词 Aircraft FUSELAGE PANELS Extended Kalman filter Fatigue crack propagation LINEARIZATION METHOD MODEL-BASED PROGNOSTICS
Extended state observer-based third-order sliding mode finite-time attitude tracking controller for rigid spacecraft
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作者 Chutiphon PUKDEBOON 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第1期145-163,共19页
In this paper,the attitude tracking control problem for a rigid spacecraft in the presence of system parameter uncertainties and external disturbances is addressed.First,a new nonsingular finite-time sliding surface i... In this paper,the attitude tracking control problem for a rigid spacecraft in the presence of system parameter uncertainties and external disturbances is addressed.First,a new nonsingular finite-time sliding surface is introduced and third-order sliding mode finite-time attitude control law is designed to achieve precise accurate tracking responses and robustness against inertia uncertainties and external disturbances.The stability of the closed-loop system is rigorously proved using the Lyapunov stability theory.Then,a new finite-time extended state observer is established to estimate total disturbances of the system.The extended stated observer-based sliding mode control technique yields improved disturbance rejection and high-precision attitude tracking.Moreover,this control law can avoid the unwinding phenomenon and overcome the input saturation constraint by introducing an auxiliary variable to compensate for the overshooting.A Lyapunov based analysis is provided to guarantee sufficiently small observation error and stabilization of the closed-loop system in finite time.Numerical simulations are conducted to verify the effectiveness of the proposed control method. 展开更多
关键词 THIRD-ORDER SLIDING MODE SLIDING MODE control extended stated observer FINITE-TIME conver-gence UNWINDING phenomenon
Fracture Analysis of Cast Iron Materials with Cracks Based on Elastoplastic Extended Finite Element Method
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作者 Yanjun Chang Qiao Song +2 位作者 Zheng Kuang Keshi Zhang Zhanguang Zheng 《固体力学学报:英文版》 SCIE EI CSCD 2019年第2期201-214,共14页
Based on the ABAQUS platform for finite element analysis, the extended finite element method (XFEM) considering elastoplastic constitutive relationship is developed, by which the displacement discontinuity across the ... Based on the ABAQUS platform for finite element analysis, the extended finite element method (XFEM) considering elastoplastic constitutive relationship is developed, by which the displacement discontinuity across the crack surface and the strong nonlinearity near the crack tip can be described more accurately. The strip specimens with unilateral cracks and central cracks under uniaxial tension are simulated using the XFEM and the FEM, respectively. The J-integral across the crack on each incremen t is calcula ted using the equivale nt domain integral met hod (EDIM), the interaction integral met hod and the FEM, respectively. The effec ts of mesh size and mesh shape near the crack tip, element type and different calculation methods on the accuracy of J-integral are analyzed. The simulation results show that the XFEM is more accurate than the FEM with the same element size and type. The fracture tests of cast iron specimens with unilateral cracks under uniaxial tension are performed, and the J-integral criterion is valid to predict the fracture initiation in numerical simulation. The critical value of J-integral is calculated using the EDIM of the XFEM. The comparisons demonstrate that the simulated elastoplastic load-displacement curves with the XFEM are in good agreement with the experimental results. 展开更多
关键词 J-INTEGRAL Extended FINITE element Elastoplasticity FRACTURE CRITERION
Outcomes of central hepatectomy versus extended hepatectomy 预览
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作者 Jenny Chan Luke Bradshaw +9 位作者 Nezor Houli Laurence Weinberg Marcos V Perini Michael Fink Vijayaragavan Muralidharan Graham Starkey Robert Jones Bao Zhong Wang Christopher Christophi Mehrdad Nikfarjam 《国际肝胆胰疾病杂志:英文版》 SCIE CAS CSCD 2019年第3期249-254,共6页
Background: Central hepatectomy(CH) is more difficult than extended hepatectomy(EH) and is associated with greater morbidity. In this modern era of liver management with aims to prevent posthepatectomy liver failure(P... Background: Central hepatectomy(CH) is more difficult than extended hepatectomy(EH) and is associated with greater morbidity. In this modern era of liver management with aims to prevent posthepatectomy liver failure(PHLF), there is a need to assess outcomes of CH as a parenchyma-sparing procedure for centrally located liver tumors. Methods: A total of 178 major liver resections performed by specialist surgeons from two Australian tertiary institutions between June 2009 and March 2017 were reviewed. Eleven patients had CH and 24 had EH over this study period. Indications and perioperative outcomes were compared between the groups. Results: The main indication for performing CH was colorectal liver metastases. There was no perioperative mortality in the CH group and four(16.7%) in the EH group( P = 0.285). No group differences were found in median operative time [CH vs. EH: 450 min(290–840) vs. 523 min(310–860), P = 0.328], intraoperative blood loss [850 mL(40 0–150 0) vs. 650 mL(10 0–20 0 0), P = 0.746] or patients requiring intraoperative blood transfusion [1(9.1%) vs. 7(30.4%), P = 0.227]. There was a trend towards fewer hepatectomyspecific complications in the CH group [3(27.3%) vs. 13(54.2%), P = 0.167], including PHLF(CH vs. EH: 0 vs. 29.2%, P = 0.072). Median length of stay was similar between groups [CH vs. EH: 9 days(5–23) vs. 12 days(4–85), P = 0.244]. Conclusions: CH has equivalent postoperative outcomes to EH. There is a trend towards fewer hepatectomy-specific complications, including PHLF. In appropriate patients, CH may be considered as a safe parenchyma-sparing alternative to EH. 展开更多
关键词 CENTRAL HEPATECTOMY Mesohepatectomy CENTRAL bisectionectomy CENTRAL bisegmentectomy EXTENDED HEPATECTOMY
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Nuclear matter and neutron star properties with the extendedNambu-Jona-Lasinio model
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作者 陈晏军 《中国物理C:英文版》 SCIE CAS CSCD 2019年第3期82-90,共9页
An extended Nambu-Jona-Lasinio(eNJL) model with nucleons as the degrees of freedom is used to investigate properties of nuclear matter and neutron stars(NSs),including the binding energy and symmetry energy of the nuc... An extended Nambu-Jona-Lasinio(eNJL) model with nucleons as the degrees of freedom is used to investigate properties of nuclear matter and neutron stars(NSs),including the binding energy and symmetry energy of the nuclear matter, the core-crust transition density, and mass-radius relation of NSs. The fourth-order symmetry energy at saturation density is also investigated. When the bulk properties of nuclear matter at saturation density are used to determine the model parameters, the double solutions of parameters are obtained for a given nuclear incompressibility. It is shown that the isovector-vector interaction has a significant influence on the nuclear matter and NS properties, and the sign of isovector-vector coupling constant is critical in the determination of the trend of the symmetry energy and equation of state. The effects of the other model parameters and symmetry energy slope at saturation density are discussed. 展开更多
关键词 NEUTRON STARS nuclear matter EXTENDED Nambu-Jona-Lasinio model SYMMETRY energy
Fast density peak-based clustering algorithm for multiple extended target tracking 预览
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作者 SHEN Xinglin SONG Zhiyong +1 位作者 FAN Hongqi FU Qiang 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第3期435-447,共13页
The key challenge of the extended target probability hypothesis density (ET-PHD) filter is to reduce the computational complexity by using a subset to approximate the full set of partitions. In this paper, the influen... The key challenge of the extended target probability hypothesis density (ET-PHD) filter is to reduce the computational complexity by using a subset to approximate the full set of partitions. In this paper, the influence for the tracking results of different partitions is analyzed, and the form of the most informative partition is obtained. Then, a fast density peak-based clustering (FDPC) partitioning algorithm is applied to the measurement set partitioning. Since only one partition of the measurement set is used, the ET-PHD filter based on FDPC partitioning has lower computational complexity than the other ET-PHD filters. As FDPC partitioning is able to remove the spatially close clutter-generated measurements, the ET-PHD filter based on FDPC partitioning has good tracking performance in the scenario with more clutter-generated measurements. The simulation results show that the proposed algorithm can get the most informative partition and obviously reduce computational burden without losing tracking performance. As the number of clutter-generated measurements increased, the ET-PHD filter based on FDPC partitioning has better tracking performance than other ET-PHD filters. The FDPC algorithm will play an important role in the engineering realization of the multiple extended target tracking filter. 展开更多
关键词 FAST DENSITY peak-based clustering (FDPC) MULTIPLE extended target partition probability hypothesis DENSITY (PHD) filter track.
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Extended Phase Space in the Framework of Holography
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作者 Z.Sherkatghanad B.Mirza +1 位作者 H.Nadi M.Rostami 《理论物理通讯:英文版》 SCIE CAS CSCD 2019年第5期590-598,共9页
We consider a holographic extended phase space in the presence of Reissner-Nordstrom-Anti-de Sitter(RNAdS) and Born-Infeld-Anti-de Sitter(BI-AdS) black holes in the bulk. In this extended phase space the cosmological ... We consider a holographic extended phase space in the presence of Reissner-Nordstrom-Anti-de Sitter(RNAdS) and Born-Infeld-Anti-de Sitter(BI-AdS) black holes in the bulk. In this extended phase space the cosmological constant is investigated as pressure and volume is defined as the codimension one-time slice in the bulk geometry enclosed by the minimal area appearing in the computation of the holographic entanglement entropy. These thermodynamics quantities can serve as probes of the underlying phase transition dictated by black hole thermodynamics, but do not describe different structures. We find that the isocharges on the pressure-volume plane exhibit a Van der Waals-like structure, for RN-AdS black holes in the background. For BI-AdS black holes, we observe the analogy with a Van der Waals liquid-gas system for βQ > 1/2 and Reentrant phase transition for βQ < 1/2 in the holographic extended phase space. The same holographic thermodynamic behavior is observed when we use the fidelity susceptibility as the volume and the cosmological constant as the pressure for RN-AdS black hole in the background. 展开更多
关键词 EXTENDED PHASE space HOLOGRAPHY ENTANGLEMENT entropy PHASE COSMOLOGY
New repairable system model with two types repair based on extended geometric process 预览
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作者 WANG Junyuan YE Jimin XIE Pengfei 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第3期613-623,共11页
A simple repairable system with one repairman is considered. As the system working age is up to a specified time T, the repairman will repair the component preventively, and it will go back to work as soon as the repa... A simple repairable system with one repairman is considered. As the system working age is up to a specified time T, the repairman will repair the component preventively, and it will go back to work as soon as the repair finished. When the system failure, the repairman repair it immediately. The time interval of the preventive repair and the failure correction is described with the extended geometric process. Different from the available replacement policy which is usually based on the failure number or the working age of the system, the bivariate policy (T,N) is considered. The explicit expression of the long-run average cost rate function C(T,N) of the system is derived. Through alternatively minimize the cost rate function C(T,N), the optimal replacement policy (T?,N?) is obtained, and it proves that the optimal policy is unique. Numerical cases illustrate the conclusion, and the sensitivity analysis of the parameters is carried out. 展开更多
关键词 EXTENDED geometric process AVERAGE cost rate REPLACEMENT policy RENEWAL REWARD theorem
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Electromagnetic scattering of charged particles in a strong wind-blown sand electric field
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作者 李兴财 高璇 王娟 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第3期218-222,共5页
Some field experimental results have shown that the moving sands or dust aerosols in nature are usually electrified,and those charged particles also produce a strong electric field in air, which is named as wind-blown... Some field experimental results have shown that the moving sands or dust aerosols in nature are usually electrified,and those charged particles also produce a strong electric field in air, which is named as wind-blown sand electric field.Some scholars have pointed out that the net charge on the particle significantly enhances its electromagnetic(EM) extinction properties, but up to now, there is no conclusive research on the effect of the environmental electric field. Based on the extended Mie theory, the effect of the electric field in a sandstorm on the EM attenuation properties of the charged larger dust particle is studied. The numerical results indicate that the environmental electric field also has a great influence on the particle’s optical properties, and the stronger the electric field, the bigger the effect. In addition, the charged angle, the charge density, and the particle radius all have a specific impact on the charged particle’s optical properties. 展开更多
关键词 wind-blown SAND electric field extended MIE theory CHARGED particle scattering
Efficient derivation of extended pluripotent stem cells from NOD-scid II2rg-/-mice
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作者 Yaqin Du Ting Wang +10 位作者 Jun Xu Chaoran Zhao Haibo Li Yao Fu Yaxing Xu Liangfu Xie Jingru Zhao Weifeng Yang Ming Yin Jinhua Wen Hongkui Deng 《蛋白质与细胞:英文版》 SCIE CAS CSCD 2019年第1期31-42,共12页
Recently we have established a new culture condition enabling the derivation of extended pluripotent stem(EPS)cells,which,compared to conventional pluripotent stem cells,possess superior developmental potential and ge... Recently we have established a new culture condition enabling the derivation of extended pluripotent stem(EPS)cells,which,compared to conventional pluripotent stem cells,possess superior developmental potential and germline competence.However,it remains unclear whether this condition permits derivation of EPS cells from mouse strains that are refractory or non-permissive to pluripotent cell establishment.Here,we show that EPS cells can be robustly generated from non-permissive NOD-sc/d Il2rg 1 mice through de novo derivation from blastocysts.Furthermore,these cells can also be efficiently generated by chemical reprogramming from embryonic NOD-sc/d II2rg-/-fibroblasts.NOD-sc/d II2rg-/-EPS cells can be expanded for more than 20 passages with genomic stability and can be genetically modified through gene targeting.Notably,these cells contribute to both embryonic and extraembryonic lineages in vivo.More importantly,they can produce chimeras and integrate into the E13.5 genital ridge.Our study demonstrates the feasibility of generating EPS cells from refractory mouse strains,which could potentially be a general strategy for deriving mouse pluripotent cells.The generation of NOD-sc/d II2rg-/-Yaqin Du and Ting Wang contributed equally to this work.Electronic supplementary material The online version of this article(https://doi.org/10.1007/s13238-018-0558-z)contains supplementary material,which is available to authorized users.EPS cell lines permits sophisticated genetic modification in NOD-scid II2rg-/-mice,which may greatly advance the optimization of humanized mouse models for biomedical applications. 展开更多
关键词 EXTENDED PLURIPOTENT stem cell NOD-scid II2rg-/-mice EMBRYONIC and extraembryonic LINEAGES chemical REPROGRAMMING
Ionospheric time delay corrections based on the extended single layer model over low latitude region
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作者 Sahithi Karanam D.Venkata Ratnam J.R.K.Kumar Dabbakuti 《大地测量与地球动力学:英文版》 2019年第3期235-240,共6页
Ionospheric delay error is considered to be one of the most prominent factors impacting the Global Navigation Satellite Systems(GNSS) positioning and navigation accuracies. Due to dispersive nature and anisotropic of ... Ionospheric delay error is considered to be one of the most prominent factors impacting the Global Navigation Satellite Systems(GNSS) positioning and navigation accuracies. Due to dispersive nature and anisotropic of the ionosphere above certain regions, the positioning accuracy is seriously affected when using a precision-limited model. In this paper, an attempt has been taken to estimate ionosphere-delays based on Planar Fit(PF) and Spherical Harmonic Function(SHF) models by applying the commonly used single layer Model(SLM) and an extended single layer model(ESLM) which has been explored sparsely over the region. The results show that ESLM of PF and SHF techniques performed better in estimating ionospheric delay compared to the existing SLM model. Although the performance of the ESLM approach is almost comparable to the SLM results during the quiet ionospheric conditions, the ESLM-PF and ESLMSHF models led to respective improvements of 4.66% and 7.14% over the classically used SLM model under the disturbed ionospheric conditions. In view of the uneven variability of equatorial/low latitude ionosphere above the Indian subcontinental region, the suitability of ESLM-PF and ESLM-SHF models has been emphasized and suggested for assessing its completeness and reliableness across other parts of the globe. The output of this work may be useful for high precession GNSS positioning through mitigating the ionospheric delays under quiet as well as varied ionospheric conditions across the low/equatorial latitude regions. 展开更多
关键词 Global Navigation Satellite Systems(GNSS) Planar fit(PF) Spherical HARMONIC Function(SHF) EXTENDED SINGLE layer model(ESLM)
Diversity considerations in wideband radar detection of migrating targets in clutter
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作者 Francois LE CHEVALIER Nikita PETROV 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第4期27-36,共10页
Wideband radars have been proposed for detection of moving targets, with unique capability of non-ambiguous detection due to range migration. Moreover, frequency diversity has long been used for mitigating the fading ... Wideband radars have been proposed for detection of moving targets, with unique capability of non-ambiguous detection due to range migration. Moreover, frequency diversity has long been used for mitigating the fading effects caused by target and clutter fluctuations. The real benefits of wideband radars are difficult to analyze, since they derive from the combined effects of target resolution in range, migration over successive cells of clutter, Doppler resolution and instantaneous bandwidth, and residual ambiguities in Doppler. In order to contribute to a better understanding of the benefits of agile transmissions for detection of moving targets, clutter cancelling performances of wideband radars are examined, demonstrating clear benefits from diversity on clutter and target, primarily – but not only – obtained through target migration effects. Special attention is given to long-range surveillance and tracking, and new results on detection of moving targets in clutter will be provided to demonstrate the effectiveness of these new architectures for small targets detection at long range, in difficult environments. Finally, recommendations for system designs that improve the discrimination of moving targets against fixed and diffuse clutter are presented. 展开更多
关键词 radar extended TARGET frequency DIVERSITY WIDEBAND DETECTION TARGET migration CLUTTER cancelling
Partially known information attack on SM2 key exchange protocol
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作者 Wei WEI Jiazhe CHEN +1 位作者 Dan LI Beibei WANG 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第3期57-70,共14页
SM2 key exchange protocol is a part of the SM2 public key cryptographic algorithm based on elliptic curves which has been issued by Chinese State Cryptography Administration since 2010.Under the guide of Chinese gover... SM2 key exchange protocol is a part of the SM2 public key cryptographic algorithm based on elliptic curves which has been issued by Chinese State Cryptography Administration since 2010.Under the guide of Chinese government,SM2 has been widely used in Chinese commercial applications.This paper gives the first partially known information attack on SM2 key exchange protocol.Our attack is based on a technique modified from the hidden number problem(HNP)which was introduced originally to study the bit security of Diffie-Hellman and related schemes.We present a polynomial-time algorithm which could recover the user's secret key when given about half least significant bits of the two unknown intermediate values in each congruence over about 30 to 40 instances.Compared with the standard HNP,our approach deals with congruence involved two independent unknown variables and each of them possesses the same size as the secret key.Moreover,our results almost coincide with the previous best result among the same field considering the extreme case in which one variant is completely revealed. 展开更多
关键词 SM2 key exchange protocol CRYPTANALYSIS information LEAKAGE LATTICE ATTACK extended hidden number problem
Labeled box-particle CPHD filter for multiple extended targets tracking 预览
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作者 ZOU Zhibin SONG Liping CHENG Xuan 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第1期57-67,共11页
In multiple extended targets tracking, replacing traditional multiple measurements with a rectangular region of the nonzero volume in the state space inspired by the box-particle idea is exactly suitable to deal with ... In multiple extended targets tracking, replacing traditional multiple measurements with a rectangular region of the nonzero volume in the state space inspired by the box-particle idea is exactly suitable to deal with extended targets, without distinguishing the measurements originating from the true targets or clutter. Based on our recent work on extended box-particle probability hypothesis density (ET-BP-PHD) filter, we propose the extended labeled box-particle cardinalized probability hypothesis density (ET-LBP-CPHD) filter, which relaxes the Poisson assumptions of the extended target probability hypothesis density (PHD) filter in target numbers, and propagates not only the intensity function but also cardinality distribution. Moreover, it provides the identity of individual target by adding labels to box-particles. The proposed filter can improve the precision of estimating target number meanwhile achieve targets' tracks. The effectiveness and reliability of the proposed algorithm are verified by the simulation results. 展开更多
关键词 EXTENDED target MULTIPLE TARGETS tracking labled boxparticle cardinalized PROBABILITY HYPOTHESIS density (CPHD).
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Time-varying formation tracking for uncertain second-order nonlinear multi-agent systems
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作者 Mao-peng RAN Li-hua XIE Jun-cheng LI 《信息与电子工程前沿:英文版》 SCIE EI CSCD 2019年第1期76-87,共12页
Our study is concerned with the time-varying formation tracking problem for second-order multi-agent systems that are subject to unknown nonlinear dynamics and external disturbance, and the states of the followers for... Our study is concerned with the time-varying formation tracking problem for second-order multi-agent systems that are subject to unknown nonlinear dynamics and external disturbance, and the states of the followers form a predefined time-varying formation while tracking the state of the leader. The total uncertainty lumps the unknown nonlinear dynamics and the external disturbance, and is regarded as an extended state of the agent. To estimate the total uncertainty, we design an extended state observer(ESO). Then we propose a novel ESO based time-varying formation tracking protocol. It is proved that, under the proposed protocol, the ESO estimation error and the time-varying formation tracking error can be made arbitrarily small. An application to the target enclosing problem for multiple unmanned aerial vehicles(UAVs) verifies the effectiveness and superiority of the proposed approach. 展开更多
关键词 Multi-agent system TIME-VARYING FORMATION FORMATION tracking Nonlinear dynamics Extended state observer(ESO)
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