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On convergence of covariance matrix of empirical Bayes hyper-parameter estimator

Control Theory and Technology 2024年第2期22卷 149-162页

作者： yue ju Biqiang Mu Tianshi Chen School of Data Science and Shenzhen Research Institute of Big Data The Chinese University of Hong KongShenzhenShenzhen518172GuangdongChina Division of Decision and Control Systems School of Electrical Engineering and Computer ScienceKTH Royal Institute of Technology10044StockholmSweden Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and System ScienceChinese Academy of SciencesBeijing100190China

Regularized system identification has become the research frontier of system identification in the past *** related core subject is to study the convergence properties of various hyper-parameter estimators as the sample size goes to *** this paper,we consider one commonly used hyper-parameter estimator,the empirical Bayes(EB).Its convergence in distribution has been studied,and the explicit expression of the covariance matrix of its limiting distribution has been ***,what we are truly interested in are factors contained in the covariance matrix of the EB hyper-parameter estimator,and then,the convergence of its covariance matrix to that of its limiting distribution is *** general,the convergence in distribution of a sequence of random variables does not necessarily guarantee the convergence of its covariance ***,the derivation of such convergence is a necessary complement to our theoretical analysis about factors that influence the convergence properties of the EB hyper-parameter *** this paper,we consider the regularized finite impulse response(FIR)model estimation with deterministic inputs,and show that the covariance matrix of the EB hyper-parameter estimator converges to that of its limiting ***,we run numerical simulations to demonstrate the efficacy of ourtheoretical results.

关键词： Regularized system identification Hyper-parameter estimator Empirical Bayes Convergence of covariance matrix

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Paraffin–CaCl_(2)·6H_(2)O dosage effects on the strength and heat transfer characteristics of cemented tailings backfill

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 60-70页

作者： hai Li Aibing Jin Shuaijun Chen Yiqing Zhao You ju Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine University of Science and Technology BeijingBeijing 100083China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China

The challenge of high temperatures in deep mining remains harmful to the health of workers and their production efficiency The addition of phase change materials (PCMs) to filling slurry and the use of the cold storage function of these materials to reduce downhole temperatures is an effective approach to alleviate the aforementioned ***–CaCl_(2)·6H_(2)O composite PCM was prepared in the *** composition,phase change latent heat,thermal conductivity,and cemented tailing backfill (CTB) compressive strength of the new material were *** heat transfer characteristics and endothermic effect of the PCM were simulated using Fluent *** results showed the following:(1) The new paraffin–CaCl_(2)·6H_(2)O composite PCM improved the thermal conductivity of native paraffin while avoiding the water solubility of CaCl_(2)·6H_(2)O.(2) The calculation formula of the thermal conductivity of CaCl_(2)·6H_(2)O combined with paraffin was deduced,and the reasons were explained in principle.(3) The“enthalpy–mass scale model”was applied to calculate the phase change latent heat of nonreactive composite PCMs.(4)The addition of the paraffin–CaCl_(2)·6H_(2)O composite PCM reduced the CTB strength but increased its heat absorption *** research can give a theoretical foundation for the use of heat storage backfill in green mines.

关键词： paraffin–CaCl_(2)·6H_(2)O heat transfer simulation heat calculation phase change material-based backfill latent heat of formula

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Diagnostic accuracy and its affecting factors of dual-source CT for assessment of coronary stents patency and in-stent restenosis

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Chinese Medical Journal 2012年第11期125卷 1936-1940页

作者： ZHANG Xing-hua YANG Li WU Jian ju hai-yue ZHANG Fan HE Bin CHEN Yun-dai Department of Radiology People＇s Liberation Army General Hospital Beijing 100853 China Department of Cardiology People＇s Liberation Army General Hospital Beijing 100853 China

Background In-stent restenosis is a common complication after stent implantation. However, the assessment of stent lumen in computed tomography （CT） coronary angiography is limited by multiple factors. Our study aimed to evaluate the accuracy and the suspected affecting factors in diagnosing coronary in-stent restenosis by dual-source CT （DSCT） compared with coronary angiography. Methods One hundred and fifteen stents in 50 patients were evaluated with DSCT before coronary angiography for the detection of coronary in-stent restenosis （〉 50% luminal narrowing）. Patency of each stent was analyzed by two independent expert radiologists blinded to the results of coronary angiography. The relationship between diagnostic accuracy and the suspected factors including age, body mass index （BMI）, heart rate, variation of heart rate, radiation dose, image quality, location and stent characteristics （type, material, diameter, length and strut thickness） was assessed with both univariate and multivariate analysis. The fitting of a Logistic regression model was evaluated using a receiver operating characteristic （ROC） curve. Results Mean stent diameter was （2.9±0.4） mm. Sensitivity, specificity, positive and negative predictive values and accuracy of DSCT in detection of in-stent restenosis were 69.2%, 91.2%, 50.0%, 95.9%, and 88.7%, respectively. In a subgroup of stents with a diameter 〉3.0 mm, sensitivity, specificity, positive and negative predictive values and accuracy were 100.0%, 96.5%, 75.0%, 100.0%, and 96.8%, respectively. Stent diameter 〈3.0 mm and poor image quality were associated with poor diagnostic accuracy （P 〈0.05）. The area under curve of ROC was 0.79. Conclusion DSCT can provide high accuracy for the assessment of in-stent restenosis in stents with a diameter 〉3.0 mm, and can play an important role in ruling out in-stent restenosis.

关键词： tomography, X-Ray computed, stents coronary restenosis coronary angiography

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Experimental and theoretical insight into carbamazepine degradation by chlorine-based advanced oxidation processes:Efficiency,energy consumption,mechanism and DBPs formation

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Journal of Environmental Sciences 2024年第5期139卷 72-83页

作者： Chunwei Liu Zuo Tong How yue ju Li Feng Xuefeng Ren Mohamed Gamal El-Din Key Laboratory ofCoal Processing and Efficient Utilization of Ministry of Education School of Chemical Engineering and TechnologyChina University of Mining and TechnologyJiangsu 221116China Department of Civil and Environmental Engineering University of AlbertaEdmonton T6G 1H9AlbertaCanada School of Environment and Spatial Informatics China University of Mining and TechnologyJiangsu 221116China Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation ofhainan Province School of Ecology and EnvironmentHainan UniversityHainan 570228China

Chlorine has been widely used in different advanced oxidation processes(AOPs)for micropollutants *** this study,different chlorine-based AOPs,namely medium pressure(MP)UV/chlorine,low pressure(LP)UV/chlorine,and in-situ chlorination,were compared for carbamazepine(CBZ)removal efficiency,energy consumption,and disinfection by-products(DBPs)*** three processes could achieve nearly 100%CBZ removal,while the reaction time needed by in-situ chlorination was double the time required by UV/chlorine *** energy consumed per magnitude of CBZ removed(EE/O)of MP UV/chlorine was 13 times higher than that of LP UV/chlorine,and relative to that of in-situ chlorination ***,MP and LP UV/chlorine processes generated one to two orders of magnitude more hydroxyl radicals(^(·)OH)and reactive chlorine species(RCS)than in-situ ***,RCS were the dominant reactive species,contributing to 78.3%,75.6%,and 71.6% of CBZ removal in MP,LP UV/chlorine,and in-situ chlorination,*** to the Gibbs free energy barriers between CBZ and RCS/^(·)OH calculated based on density functional theory(DFT),RCS had more reaction routes with CBZ and showed lower energy barrier in the main CBZ degradation pathways like epoxidation and formation of *** applied to secondary wastewater effluent,UV/chlorine and in-situ chlorination produced overall DBPs ranging from 104.77 to 135.41μg/***,the production of chlorate during UV/chlorine processes was 15 times higher than that during in-situ chlorination.

关键词： UV/chlorine In-situ chlorination Energy efficiency Role of reactive species DFT calculation Disinfection by-products

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双呼吸导航门控高分辨黑血磁共振序列冠状动脉管壁成像

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中国医学科学院学报 2013年第3期35卷 305-310页

作者：具海月杨立程流泉蔡祖龙中国人民解放军总医院放射科北京100853

目的探讨相位排序自动门控窗选择(PAWS)及同时多重容积(SMV)算法双呼吸导航门控高分辨黑血磁共振(MR)序列对冠状动脉管壁的显示效能。方法志愿者21名,行右冠状动脉(RCA)及左前降支(LAD)横断面高分辨黑血MR检查,将图像质量进行定性分级(0... 详细信息

目的探讨相位排序自动门控窗选择(PAWS)及同时多重容积(SMV)算法双呼吸导航门控高分辨黑血磁共振(MR)序列对冠状动脉管壁的显示效能。方法志愿者21名,行右冠状动脉(RCA)及左前降支(LAD)横断面高分辨黑血MR检查,将图像质量进行定性分级(0级=无法评价,1级=较差,2级=较好,3级=很好)。排除0级和1级图像,2级和3级进一步测量RCA和/或LAD管壁厚度,两者差异采用独立样本t检验进行评价。结果全部38幅图像中,14幅为2级,17幅为3级,RCA及LAD管壁厚度分别为(0.94±0.16)和(0.89±0.15)mm,差异无统计学意义(t=-0.790,P>0.05)。结论 PAWS及SMV算法双呼吸导航门控高分辨黑血MR序列在冠状动脉管壁成像方面具有初步临床应用价值和可行性。

关键词：导航黑血磁共振成像高分辨冠状动脉管壁成像

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比较相位排序自动门控窗选择及同时多重容积算法双呼吸导航门控与屏气二维双反转恢复快速自旋回波黑血心脏MR序列的成像质量

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中国医学影像技术 2011年第7期27卷 1503-1507页

作者：具海月杨立程流泉蔡祖龙中国人民解放军总医院放射科

目的探讨分别采用相位排序自动门控窗选择(PAWS)及同时多重容积(SMV)算法双呼吸导航门控与屏气二维双反转恢复快速自旋回波(2DNAV DIR FSE,2DBH DIR FSE)黑血心脏MR序列的图像质量,评价前者的临床应用可行性及价值。方法对15名健康成年... 详细信息

目的探讨分别采用相位排序自动门控窗选择(PAWS)及同时多重容积(SMV)算法双呼吸导航门控与屏气二维双反转恢复快速自旋回波(2DNAV DIR FSE,2DBH DIR FSE)黑血心脏MR序列的图像质量,评价前者的临床应用可行性及价值。方法对15名健康成年志愿者分别进行2DNAV DIR FSE及2DBH DIR FSE黑血MR心脏成像,对比评价两个序列对应层面的图像质量(定性评价及定量分析)。结果 2名医师评估2DNAV DIR FSE序列图像质量的一致性较好(Kappa=0.573,P<0.01);2名医师对2DNAV DIR FSE序列相对诊断可信性主观评分显著相关(r=0.733,P<0.01)。2DNAV DIR FSE序列各层面图像左心室心肌、心腔信噪比及左心室心肌/心腔对比噪声比均低于2DBH DIRFSE序列(t=-15.847、-18.399、-14.824,P均<0.05)。结论采用PAWS及SMV算法的2DNAV DIR FSE黑血MR序列对于屏气配合差的患者优势明显,但对屏气配合良好者不宜作为首选。

关键词：黑血技术磁共振成像信噪比对比噪声比

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Multiple factors influencing high-purity indium electrolytic refining

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Chinese Journal of Chemical Engineering 2024年第7期71卷 148-160页

作者： Hong-Qiang Fan Fei Li Hong-Xing Zheng Wu-ji Pan Mei-Zhen Wu Yashar Behnamian ju-Bo Peng Dong-hai Lin State Key Laboratory of Advanced Special Steel&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Shanghai Engineering Research Center for Integrated Circuits and Advanced Display Materials Shanghai UniversityShanghai 200444China Research&Development Center Yunnan Tin Group(Holding)Limited CompanyKunming 650032China Department of Chemical and Materials Engineering University of AlbertaEdmonton T6G 2V4AlbertaCanada School of Energy and Materials Shanghai Key Laboratory of Engineering Materials Application and EvaluationShanghai Polytechnic UniversityShanghai 201209China

The effects of various contaminants in the electrolytic refinement of indium were investigated using a glow discharge mass spectrometer(GDMS).The effects of several factors such as the indium ion(In3+)concentration,the sodium chloride(NaCl)concentration,the current density,the gelatin concentration,the pH,and the electrode distance,were *** variations in impurity levels concerning gelatin concentration were *** the gelatin and In3+concentration were moderately positively correlated with the Pb *** Sb concentration was associated positively with the NaCl concentration,while the Ti concentration had an adverse correlation with the NaCl *** Bi element content was positively linked to the electrode *** the current density increased,Cu,Pb,and Bi impurities initially rose and then eventually ***,a critical current density of 45 A·m^(-2) was identified in this behavior.

关键词： High-purity indium Electrolysis Multiple factors Electrochemistry Purification

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脑动脉和静脉增强曲线最高值及增强峰值对CT灌注参数及其信噪比的影响

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中华放射学杂志 2007年第7期41卷 687-691页

作者：具海月高思佳徐克王强中国医科大学附属第一医院放射科

目的探讨脑动、静脉增强曲线最高值及增强峰值对 CT 灌注参数及其图像信噪比(SNR)的影响。方法 17例患者行多层螺旋 CT(MSCT)脑灌注扫描后经灌注软件后处理,每一病例处理6次,生成不同的动、静脉增强曲线。记录每次生成的动、静脉曲线最... 详细信息

目的探讨脑动、静脉增强曲线最高值及增强峰值对 CT 灌注参数及其图像信噪比(SNR)的影响。方法 17例患者行多层螺旋 CT(MSCT)脑灌注扫描后经灌注软件后处理,每一病例处理6次,生成不同的动、静脉增强曲线。记录每次生成的动、静脉曲线最高值和增强峰值及同侧脑白质、灰质感兴趣区(ROI)内灌注参数,即脑血流量(CBF)、脑血容量(cBV)、平均通过时间(MTT)和表面通透性(PS)的平均值,并由参数平均值除以相应标准差,计算相应 SNR。应用 SPSS 10.0软件包对数据进行 Pearson 相关分析及配对 t 检验。结果 (1)白质平均 SNR_(CBF)为1.61±0.36,灰质为3.01±1.14;白质平均 SNR_(CBV)为2.47±0.66,灰质为3.68±1.12;白质平均 SNR_(MTT)为1.54±0.33,灰质为2.53±0.84;白质平均 SNR_(ps)为0.50±0.16,灰质为0.62±0.21。动、静脉曲线最高值及增强峰值与白质和灰质平均 SNR_(CBF)、SNR(CBV) 及 SNR_(MTT) 值(r 值介于0.332～0.922,P 值均0.05)。(2)高、低静脉组之间平均 CBF、CBV 及 PS 值的差异均有统计学意义(t 值介于3.830～5.337,P 值均0.05)及高、低动脉组之间所有灌注参数平均值( t 值介于-0.987～1.197,P 值均>0.05)差异均无统计学意义。结论动、静脉曲线最高值及增强峰值对脑CT 灌注图像 SNR 的影响具有统计学意义;静脉曲线最高值及增强峰值对灌注参数平均值的影响具有统计学意义;图像后处理时应该将动、静脉曲线调高以提高灌注参数的准确性及图像 SNR。

关键词：脑血管循环体层摄影术 x线计算机灌注局部因素分析统计学

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Clinical analysis of patients with deep sternal wound infection-induced sepsis:a retrospective cohort study

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Emergency and Critical Care Medicine 2024年第2期4卷 67-73页

作者： Bin Song Zhentian Cui Hongyan ju yue Sun Dandan Liu Guanggang Li Department of Critical Care 7th Medical Center of Chinese PLA General HospitalBeijingChina Department of Cardiac and Macrovascular Surgery 7th Medical Center of Chinese PLA General HospitalBeijingChina

Background:This study aimed to summarize the clinical characteristics of patients with deep sternal wound infection-induced sepsis after median sternotomy and improve the treatment outcomes of infection-related ***:A retrospective cohort study was conducted on 21 patients with deep sternal wound infection-induced sepsis after median sternotomy who were admitted to the Department of Critical *** clinical manifestations,laboratory test results,infection control,and organ and nutritional support of the patients were summarized,and the follow-up data were ***:The primary symptoms of deep sternal wound infection-induced sepsis included dyspnea,high fever,chills,and altered state of *** test results revealed increased inflammatory markers and decreased oxygenation *** and liver function injury were observed in 8 and 4 patients,respectively;18 and 12 patients demonstrated elevated D-dimer and N-terminal Pro B type natriuretic peptide levels,*** the 8 patients whose wound secretions tested positive for bacteria,Acinetobacter baumannii and Staphylococcus aureus infections were present in 6 and 2 patients,*** of the 6 patients whose blood cultures tested positive for bacteria demonstrated Candida albicans *** patients received ventilator-assisted ventilation and 2 patients received renal replacement *** all the 21 patients,17 were cured,2 died,and 2 were ***:Postmedian sternotomy sepsis attributed to a deep sternal wound infection usually results from a preexisting *** most prominent clinical manifestation is dyspnea,which is sometimes accompanied by the impairment of organ *** prevention,proper nutrition support,and maintenance of healthy organ function are the cornerstones for successful treatment outcomes.

关键词： Clinical analysis Deep sternal wound infection Sepsis

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Federated Offline Reinforcement Learning with Proximal Policy Evaluation

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Chinese Journal of Electronics 2024年

作者： Sheng yue Yongheng DENG Guanbo WANG ju REN Yaoxue ZHANG Department of Computer Science and Technology BNRist Tsinghua University Zhongguancun Laboratory

Offline reinforcement learning (RL) has gathered increasing attention in recent years, which seeks to learn policies from static datasets without active online exploration. However, the existing offline RL approaches often require a large amount of pre-collected data and hence are hardly implemented by a single agent in practice. Inspired by the advancement of federated learning (FL), this paper studies federated offline reinforcement learning(FORL), whereby multiple agents collaboratively carry out offline policy learning with no need to share their raw trajectories. Clearly, a straightforward solution is to simply retrofit the off-the-shelf offline RL methods for FL, whereas such an approach easily overfits individual datasets during local updating, leading to instability and subpar performance. To overcome this challenge, we propose a new FORL algorithm, named model-free (MF)-FORL, thatexploits novel “proximal local policy evaluation” to judiciously push up action values beyond local data support, enabling agents to capture the individual information without forgetting the aggregated knowledge. Further, we introduce a model-based variant, MB-FORL, capable of improving the generalization ability and computational efficiency via utilizing a learned dynamics model. We evaluate the proposed algorithms on a suite of complex and high-dimensional offline RL benchmarks, and the results demonstrate significant performance gains over the baselines.

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