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Fast approximate maximum likelihood period estimation from incomplete timing data

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Chinese Journal of Aeronautics 2013年第2期26卷 435-441页

作者： Ye Haohuan Liu Zheng jiang wenli College of Electronic Science & Engineering National University of Defense Technology

To estimate the period of a periodic point process from noisy and incomplete observations, the classical periodogram algorithm is modified. The original periodogram algorithm yields an estimate by performing grid search of the peak of a spectrum, which is equivalent to the periodogram of the periodic point process, thus its performance is found to be sensitive to the chosen grid spacing. This paper derives a novel grid spacing formula, after finding a lower bound of the width of the spectral mainlobe. By employing this formula, the proposed new estimator can determine an appropriate grid spacing adaptively, and is able to yield approximate maximum likelihood estimate （MLE） with a computational complexity of O（n2）. Experimental results prove that the proposed estimator can achieve better trade-off between statistical accuracy and complexity, as compared to existing methods. Simulations also show that the derived grid spacing formula is also applicable to other estimators that operate similarly by grid search.

关键词： Grid search Maximum likelihood period estimation Periodic point process Periodogram Pulse repetition frequency

A Linear-correction Least-squares Approach for Geolocation Using FDOA Measurements Only

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Chinese Journal of Aeronautics 2012年第5期25卷 709-714页

作者： LI Jinzhou GUO Fucheng jiang wenli School of Electronic Science and Engineering National University of Defense TechnologyChangsha 410073China

A linear-correction least-squares（LCLS） estimation procedure is proposed for geolocation using frequency difference of arrival （FDOA） measurements only. We first analyze the measurements of FDOA, and further derive the Cramer-Rao lower bound （CRLB） of geoloeation using FDOA measurements. For the localization model is a nonlinear least squares（LS） estimator with a nonlinear constrained, a linearizing method is used to convert the model to a linear least squares estimator with a nonlinear con- strained. The Gauss-Newton iteration method is developed to conquer the source localization problem. From the analysis of solving Lagrange multiplier, the algorithm is a generalization of linear-correction least squares estimation procedure under the condition of geolocation using FDOA measurements only. The algorithm is compared with common least squares estimation. Comparisons of their estimation accuracy and the CRLB are made, and the proposed method attains the CRLB. Simulation re- sults are included to corroborate the theoretical development.

关键词： signal processing frequency difference of arrival Cramer-Rao lower bound linear-correction least-squares Gauss-Newton iteration method Lagrange multiplier

Reconstruction of Multifunction Radar Search Plan Based on Multiple Sequence Alignment

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Chinese Journal of Electronics 2014年第1期23卷 213-218页

作者： MA Shuang LIU Zheng jiang wenli College of Electronic Science and Engineering National University of Defense Technology

Multifunction radar(MFR) is a sophisticated sensor which could perform several different functions simultaneously. The problems of deciphering the signals of MFR and inferring the information of its capabilities have posed a great challenge to the Electronic intelligence(ELINT) society. In this paper, we propose a method to reconstruct MFR's search plan from its signals by drawing lessons from the bioinformatics approach"Multiple sequence alignment(MSA)", which is used extensively for gene analysis. In the method, the signal of MFR is represented as a structured task sequence, and is segmented into several blocks according to the inherent periodicity of the search plan. Then, these blocks are aligned optimally to distinguish the tasks relevant to the search function from the others. Simulation results show that the proposed method is applicable and effective.

关键词： Multifunction radar Search plan Multiple sequence alignment Electronic intelligence

Source localization and calibration using TDOA and FDOA measurements in the presence of sensor location uncertainty

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Science China(Information Sciences) 2014年第4期57卷 156-167页

作者： LI JinZhou GUO FuCheng jiang wenli School of Electronics Science and Engineering National University of Defense Technology

Source localization accuracy is very sensitive to sensor location *** paper performs analysis and develops a solution for locating a moving source using time difference of arrival(TDOA)and frequency difference of arrival(FDOA)measurements with the use of a calibration *** a Gaussian random signal model,we first derive the Cram′er-Rao lower bound(CRLB)for source location estimate in this *** we analyze the differential calibration technique which is commonly used in Global Positioning *** is indicated that the differential calibration cannot attain the CRLB accuracy in most cases.A closed-form solution is then proposed which takes a calibration emitter into account to reduce sensor location *** is shown analytically that under some mild approximations,our approach is able to reach the CRLB *** simulations are included to corroborate the theoretical developments.

关键词： source localization calibration time difference of arrival(TDOA) frequency difference of arrival(FDOA) sensor location uncertainty Cram′er-Rao lower bound(CRLB)

DOA estimation and mutual coupling calibration with the SAGE algorithm

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Chinese Journal of Aeronautics 2014年第6期27卷 1538-1543页

作者： Xiong Kunlai Liu Zhangmeng Liu Zheng jiang wenli College of Electronic Science and Engineering National University of Defense Technology

In this paper, a novel algorithm is presented for direction of arrival（DOA） estimation and array self-calibration in the presence of unknown mutual coupling. In order to highlight the relationship between the array output and mutual coupling coefficients, we present a novel model of the array output with the unknown mutual coupling coefficients. Based on this model, we use the space alternating generalized expectation-maximization（SAGE） algorithm to jointly estimate the DOA parameters and the mutual coupling coefficients. Unlike many existing counterparts, our method requires neither calibration sources nor initial calibration information. At the same time,our proposed method inherits the characteristics of good convergence and high estimation precision of the SAGE algorithm. By numerical experiments we demonstrate that our proposed method outperforms the existing method for DOA estimation and mutual coupling calibration.

关键词： Array self-calibration Convergence Direction of arrival estima-tion Mutual coupling Space alternating generalized expectation-maximization algorithm

体素内不相干运动直方图参数预测直肠癌神经周围浸润

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中国医学影像技术 2025年第1期41卷 99-103页

作者：张长江陈峻帆黄豆豆蒋雯丽罗银灯重庆医科大学附属第二医院放射科重庆400010

目的观察体素内不相干运动(IVIM)直方图参数预测直肠癌神经周围浸润(PNI)的价值。方法回顾性分析55例直肠癌患者,根据有无PNI将其分为阳性组(n=23)与阴性组(n=32);基于MR IVIM图像分别获取表观扩散系数(ADC)、灌注分数(f)、真实扩散系数... 详细信息

目的观察体素内不相干运动(IVIM)直方图参数预测直肠癌神经周围浸润(PNI)的价值。方法回顾性分析55例直肠癌患者,根据有无PNI将其分为阳性组(n=23)与阴性组(n=32);基于MR IVIM图像分别获取表观扩散系数(ADC)、灌注分数(f)、真实扩散系数(D)及伪扩散系数(D^(*))直方图参数,包括均值(mean)、偏度(skewness)、峰度(kurtosis)、熵(entropy),以及第25、50、75百分位数(25th、50th、75th),并进行组间比较。将组间差异有统计学意义的参数纳入二元逐步logistic回归分析,筛选预测直肠癌PNI状态的独立因素,构建联合参数模型;绘制受试者工作特征曲线,计算曲线下面积(AUC),评估各IVIM直方图参数及联合参数模型预测直肠癌PNI的效能。结果阳性组ADC_(mean)、ADC_(25th)、ADC_(50th)、ADC_(75th)、f_(mean)、f_(25th)、f_(50th)、f_(75th)及D_(entropy)^(*)均低于阴性组(P均<0.05);以上述参数预测直肠癌PNI阳性的AUC分别为0.693、0.665、0.701、0.675、0.831、0.847、0.835、0.722及0.785。基于f_(25th)及D_(entropy)^(*)构建的联合参数模型预测直肠癌PNI阳性的敏感度、特异度及AUC分别为95.65%、65.63%及0.897。结论利用IVIM直方图参数可有效预测直肠癌PNI。

关键词：直肠肿瘤磁共振成像体素内不相干运动

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Load Balancing Algorithm of Controller Based on SDN Architecture Under Machine Learning

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Journal of Systems Science and Information 2020年第6期11卷 578-588页

作者： Siyuan LIANG wenli jiang Fangli ZHAO Feng ZHAO Shaanxi Key Laboratory of Information Communication Network and Security Xi’an University of Posts&TelecommunicationsXi’an 710121China

With the rapid development of cloud computing and other related services,higher requirements are put forward for network transmission and *** to the inherent distributed characteristics of traditional networks,machine learning technology is diffcult to be applied and deployed in network *** emergence of SDN technology provides new opportunities and challenges for the application of machine learning technology in network management.A load balancing algorithm of Internet of things controller based on data center SDN architecture is *** Bayesian network is used to predict the degree of load congestion,combining reinforcement learning algorithm to make optimal action decision,self-adjusting parameter weight to adjust the controller load congestion,to achieve load balance,improve network security and stability.

关键词： software defined networks(SDN) Bayesian network reinforcement learning

Hydrocarbon Generation Characteristics of Source Rocks from Different Saline Environments in the Dongpu Depression,Bohai Bay Basin,China

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Acta Geologica Sinica(English Edition) 2021年第4期95卷 1260-1278页

作者： LI Wendu ZHANG Pengyuan jiang Fujie ZHANG Yunxian HUANG Renda XU Tianwu ZHOU Yongshui LI Longlong jiang wenli State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development Beijing 100083China State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing 102249China Basin and Reservoir Research Center China University of Petroleum(Beijing)Beijing 102249China Zhongyuan Oilfield Branch SINOPECPuyangHenan 457001China Wuxi Research Institute of Petroleum Geology Sinopec Petroleum Exploration&Production Research InstituteWuxiJiangsu 214000China Strategy Research Center of Oil and Gas Resources Ministry of Land and ResourcesBeijing 100034China

The Dongpu Depression is a secondary salt-bearing tectonic unit in the Bohai Bay Basin,eastern *** depositional environment of this depression regarding its Paleogene strata is clearly different in plane,including the saltwater environment(SE)in the north,the freshwater environment(FE)in the south and the brackish water environment(BE)in the *** result of oil and gas exploration in the Dongpu Depression shows that more than 90%of the proven oil reserves are distributed in the northern saltwater *** studies indicate that the organic geochemistry characteristics and the hydrocarbon generation capacity of the source rocks are very clearly diverse under different environments,which results in the significant differences in the proved reserves between the north and the *** order to further explore the differences in the hydrocarbon generation capacity of the source rocks under distinct depositional environments and the mechanism of their occurrence,three samples from different depositional environments(W18-5 for SE,H7-18 for BE,CH9 for FE)were used for confined gold tube pyrolysis *** results show that the CH4 yields of W18-5,H7-18 and CH9 increase with increasing temperature,the maximum yields being 405.62 mg/g TOC,388.56 mg/g TOC and 367.89 mg/g TOC,*** liquid hydrocarbon yields of W18-5,H7-18 and CH9 firstly increase with increasing temperature and then decrease after the critical *** maximum yields of C6-14 are 149.54 mg/g TOC,140.18 mg/g TOC and 116.94 mg/g TOC,the maximum yields of C14+being 852.4 mg/g TOC,652.6 mg/g TOC and 596.41 mg/g TOC,respectively for W18-5,H7-18 and *** summarize,the order of hydrocarbon potential from high to low is W18-5,H7-18 and *** this basis,through analyzing the influencing factors of hydrocarbon differences,this paper reveals that the saltwater environment is characterized by 4 factors:higher salinity,halophilic algae,high paleo-productivity and a strongly

关键词： sapropelite exinite gold-tube pyrolysis experiment hydrocarbon generation evolutionary model Dongpu Depression Bohai Bay Basin

A novel nine gene signature integrates stemness characteristics associated with prognosis in hepatocellular carcinoma

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BIOCELL 2021年第6期45卷 1425-1448页

作者： XINGHONG YAO CHENGQUAN LU JUNYI SHEN wenli jiang YAN QIU YE ZENG LIANG LI Institute of Biomedical Engineering West China School of Basic Medical Sciences&Forensic MedicineSichuan UniversityChengdu610041China Department of Radiation Oncology Sichuan Cancer Hospital&InstituteSchool of Medicine of University of Electronic Science and Technology of ChinaChengdu610041China Jinzhou City Center for Disease Control and Prevention Jinzhou121000China

Cancer stem cells(CSCs)are heterogeneous with self-renewal and differentiation *** mRNA expression-based stemness index(mRNAsi)described the similarity between tumor cells and CSCs,which is positively associated with the poor prognosis of cancer ***,the key prognostic genes related to mRNAsi in hepatocellular carcinoma(HCC)remains unclear.A 9-gene signature related to mRNAsi and HCC prognosis including PSMG3,SNRPD1,DTYMK,PIGU,NME1,TXNL4A,IPO4,PES1,and REXO4 was *** expression of this signature indicates poor prognosis of *** was an independent prognostic factor of HCC,which was significantly associated with progression of *** them,DTYMK and NME1 enriched in pyrimidine metabolism,SNRPD1 and TXNL4A enriched in spliceosome and PIGU enriched in glycosyl phosphatidylinositol(GPI)-anchor biosynthesis *** levels of IPO4,NME1,PES1,PIGU and SNRPD1 were closely associated with metastasis of HCC,and low levels of IPO4,PIGU and REOX4 were significantly associated with sorafenib resistance of *** expression of the 9-gene signature was negatively correlated with the stromal cell infiltration,and positively correlated with specific immune subtypes-related to angiogenesis,M1/M2 macrophage polarization,and M2 *** 9-gene signature was negatively correlated with the stroma,and SNRPD1 and TXNL4 were positively correlated with immune ***1 was negatively correlated with tumor ***,a 9-gene signature related to mRNAsi and poor prognosis in HCC were identified,which can be used as biomarkers for the diagnosis of HCC and functional mechanism exploration of CSCs in *** genes such as IPO4 and PIGU might drive the transition of tumor cells into CSCs which possibly controls the balance between metastasis and drug resistance in *** challenge on balance between metastasis and drug resistance for tumor therapy was firstly reported by the present study.

关键词： Stemness index Hepatocellular carcinoma Prognosis Microenvironment