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A unified Minorization-Maximization approach for estimation of general mixture models
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作者 HUANG Xi-fen LIU Deng-ge +1 位作者 ZHOU Yun-peng ZHU Fei 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第2期343-362,共20页
The mixed distribution model is often used to extract information from heteroge-neous data and perform modeling analysis.When the density function of mixed distribution is complicated or the variable dimension is high... The mixed distribution model is often used to extract information from heteroge-neous data and perform modeling analysis.When the density function of mixed distribution is complicated or the variable dimension is high,it usually brings challenges to the parameter es-timation of the mixed distribution model.The application of MM algorithm can avoid complex expectation calculations,and can also solve the problem of high-dimensional optimization by decomposing the objective function.In this paper,MM algorithm is applied to the parameter estimation problem of mixed distribution model.The method of assembly and decomposition is used to construct the substitute function with separable parameters,which avoids the problems of complex expectation calculations and the inversion of high-dimensional matrices. 展开更多
关键词 MM algorithm mixed distribution model parameter estimation assembly decomposition tech-nology parameter separation
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负离子纺织品的检测方法及应用 被引量:8
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作者 莫世清 陈衍夏 +2 位作者 施亦东 李征然 肖红艳 《染整技术》 CAS 2010年第5期42-47,共6页
主要介绍了目前国内外负离子纺织品的检测方法和研究进展,在总结课题组阶段性工作的基础上,针对目前纺织品负离子性能测试系统和检测方法提出进一步的研究设想。
关键词 负离子纺织品 检测
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竹炭纤维舒适功能针织产品的开发 被引量:3
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作者 裘玉英 《上海纺织科技》 北大核心 2011年第2期18-19,25,共3页
根据竹炭纤维与棉纤维混纺纱线的特点设计了不同的针织物组织,确定了合适的染前处理和染色工艺,并通过测试不同组织针织物的各项服用性能,包括悬垂性、透气性、吸湿排汗性和顶破强力,比较后认为,纬平针组织具有良好的透气性和悬垂性,其... 根据竹炭纤维与棉纤维混纺纱线的特点设计了不同的针织物组织,确定了合适的染前处理和染色工艺,并通过测试不同组织针织物的各项服用性能,包括悬垂性、透气性、吸湿排汗性和顶破强力,比较后认为,纬平针组织具有良好的透气性和悬垂性,其他性能也符合规定要求,由此开发出了具有良好负离子释放功能以及穿着舒适的针织产品。 展开更多
关键词 针织物 竹炭纤维 染色 整理 负离子
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A Complete Technique in Improving Quality and Production Efficiency of Juglans regia in Gongshan Derung and Nu Autonomous County
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作者 赵廷松 范志远 +5 位作者 腊叁富 邹伟烈 和玉德 潘莉 杜春花 刘娇 《Agricultural Science & Technology》 CAS 2017年第3期524-525,533,共3页
We applied water releasing from rootstocks technique and Juglans sigillata in Yangbi was pruned in the shape of opened-heart or round-heart shape. By bal- anced fertilization, survival rate of grafted walnuts can be i... We applied water releasing from rootstocks technique and Juglans sigillata in Yangbi was pruned in the shape of opened-heart or round-heart shape. By bal- anced fertilization, survival rate of grafted walnuts can be improved. We reviewed technologies to enhance walnut quality and production efficiency in Gongshan Derung and Nu Autonomous County for reference. 展开更多
关键词 Gongshan Juglans sigillata Quality and efficiency improvement tech-nology
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基于半导体制冷高效热回收装置的研究 被引量:2
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作者 杜芳莉 白大雨 房晓平 《西安航空学院学报》 2014年第1期70-73,90,共5页
从笔记本电脑散热难的问题出发,初步设计了以半导体制冷技术为基础,利用热端回收装置有效解决笔记本电脑散热问题。通过在实际应用中进行测试和试运行,实践证明该系统设计的合理性和可行性。而且通过该热回收装置有效提高了半导体制冷... 从笔记本电脑散热难的问题出发,初步设计了以半导体制冷技术为基础,利用热端回收装置有效解决笔记本电脑散热问题。通过在实际应用中进行测试和试运行,实践证明该系统设计的合理性和可行性。而且通过该热回收装置有效提高了半导体制冷效率及热量的高效利用。在此基础上融合了负离子空气清新技术,利用负离子的良好功能,给上网者提供了良好健康环境。并为解决小型设备散热提出了新的思路。 展开更多
关键词 半导体制冷 热回收装置 温差 负离子技术
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永磁端引出溅射PIG源进展
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作者 于金祥 任晓堂 宋执中 《原子能科学技术》 EI CAS CSCD 北大核心 1996年第5期434-438,共5页
介绍了永磁端引出溅射PIG离子源的进展状况,通常它可用于引出气体的与金属的单或多电荷离子,在20-30kV的引出电压下,可引出mA级的气体离子和数十微安的金属离子,功耗小于50W。同时也可用于直接引出某些电子亲合势较... 介绍了永磁端引出溅射PIG离子源的进展状况,通常它可用于引出气体的与金属的单或多电荷离子,在20-30kV的引出电压下,可引出mA级的气体离子和数十微安的金属离子,功耗小于50W。同时也可用于直接引出某些电子亲合势较强的气体元素,如H、O、F等的负离子。当采用LaB6阴极,在15-20kV的引出电压下,引出的总束流中,H-离子>50μA,0-离子接近1.4mA和F-离子可达1.8mA,功耗分别为40、50和75W左右。 展开更多
关键词 永磁 PIG 离子源 端引出 加速器
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Endoscopic tools for the diagnosis and evaluation of celiac disease 被引量:5
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作者 Gianluca Ianiro Antonio Gasbarrini Giovanni Cammarota 《World Journal of Gastroenterology》 SCIE CAS 2013年第46期8562-8570,共9页
Celiac disease(CD)is an autoimmune disease of the small bowel induced by ingestion of wheat,rye and barley.Current guidelines indicate histological analysis on at least four duodenal biopsies as the only way to diagno... Celiac disease(CD)is an autoimmune disease of the small bowel induced by ingestion of wheat,rye and barley.Current guidelines indicate histological analysis on at least four duodenal biopsies as the only way to diagnose CD.These indications are based on the conception of the inability of standard endoscopy to make diagnosis of CD and/or to drive biopsy sampling.Over the last years,technology development of endoscopic devices has greatly ameliorated the accuracy of macroscopic evaluation of duodenal villous pattern,increasing the diagnostic power of endoscopy of CD.The aim of this paper is to review the new endoscopic tools and procedures proved to be useful in the diagnosis of CD,such as chromoendoscopy,Fujinon Intelligent Chromo Endoscopy,Narrow Band Imaging,Optical Coherence Tomography,Water-Immersion Technique,confocal laser endomicroscopy,high-resolution magnification endoscopy,capsule endoscopy and I-Scan technology. 展开更多
关键词 CELIAC disease MALABSORPTION syndrome DUODENUM Diagnostic techniques and proceduresEndoscopy CHROMOENDOSCOPY Fujinon intelligent chromo ENDOSCOPY Narrow band imaging Optical coherence tomography Water-immersion technique Confocal laser ENDOMICROSCOPY High-resolution mag-nification ENDOSCOPY Capsule ENDOSCOPY I-scan tech-nology
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The Mechanism of Negative-ion Generation of Natural Fiber Fabrics
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作者 毕鹏宇 陈跃华 李汝勤 《Journal of Donghua University(English Edition)》 EI CAS 2007年第3期354-356,共3页
Generally there are three kinds of substances used as negative-ion generator in textiles, natural silicate minerals (ceramic/tourmaline), natural rare-earth minerals and natural sediment with ultra-fine pores. Based... Generally there are three kinds of substances used as negative-ion generator in textiles, natural silicate minerals (ceramic/tourmaline), natural rare-earth minerals and natural sediment with ultra-fine pores. Based on different additive, the mechanism of negative-ion generation is largely divided into three kinds, the piezoelectricity and pyroelectricity of tourmaline crystal, air ionization caused by low-level radiation and breaking up of the clusters of moisture in air when going through the ultra-free pores of natural sediment. In this paper, the negative-ion generating properties of natural fiber fabrics-cctton, wool, silk and linen were first proposed. By some kind of physical stimulation, rubbing or vibrating, natural fiber fabrics without any additive could also emit negative ions. Considering that the piezoelectric effect was observed in wool fibers, silk fibers and cellulose fibers, the piezoelectricity was studied as a mechanism of negative-ion generation of natural fiber fabrics. Another possible mechanism was the tribeelectricity produced by the sense of ntbbtng or vibrating and tip discharge of hairiness. The Final experiment results verified that the latter would be the main reason, and the electrolytic dissociation of moisture was also contributing to negative-ion generation. 展开更多
关键词 MECHANISM negativeion natural fiber PIEZOELECTRICITY TRIBOELECTRICITY
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OPKH: A Lightweight Online Approach to Protecting Kernel Hooks in Kernel Modules
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作者 田东海 李轩涯 +1 位作者 胡昌振 闫怀志 《China Communications》 SCIE CSCD 2013年第11期15-23,共9页
Kernel hooks are very important con- trol data in OS kernel. Once these data are com- promised by attackers, they can change the control flow of OS kemel's execution. Previ- ous solutions suffer from limitations in t... Kernel hooks are very important con- trol data in OS kernel. Once these data are com- promised by attackers, they can change the control flow of OS kemel's execution. Previ- ous solutions suffer from limitations in that: 1) some methods require modifying the source code of OS kernel and kernel modules, which is less practical for wide deployment; 2) other methods cannot well protect the kernel hooks and function return addresses inside kernel mo- dules whose memory locations cannot be pre- determined. To address these problems, we propose OPKH, an on-the-fly hook protection system based on the virtualization technology. Compared with previous solutions, OPKH off- ers the protected OS a fully transparent envi- ronment and an easy deployment. In general, the working procedure of OPKH can be di- vided into two steps. First, we utilise the me- mory virtualization for offiine profiling so that the dynamic hooks can be identified. Second, we exploit the online patching technique to in- strument the hooks for run-time protection. The experiments show that our system can pro- tect the dynamic hooks effectively with mini- mal performance overhead. 展开更多
关键词 kernel hook virtualization tech-nology online patching
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Performance Evaluation of Motor Insurance Companies: Panel Data Evidence from Nigeria
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作者 G. U. Ugwuanyim D. E. Onwuegbuchunam +1 位作者 D. C. Bartholomew C. C. Anikpe 《Journal of Transportation Technologies》 2021年第3期325-334,共10页
This paper evaluated performance of motor insurance companies in Nigeria. The objectives were to determine the following: 1) significant effects of claims settlements on motor insurance firms’ earned premium;2) diffe... This paper evaluated performance of motor insurance companies in Nigeria. The objectives were to determine the following: 1) significant effects of claims settlements on motor insurance firms’ earned premium;2) differences in managerial/technological capabilities among the companies and 3) effects of policy (or time effect) on insurance firms’ output within the study </span><span style="font-family:Verdana;">period. Panel data obtained for this study comprised operational data on</span><span style="font-family:Verdana;"> premium earned and direct claims settlement by these companies over a period </span><span style="font-family:Verdana;">of six (6) years. Using panel data statistical models, we found that direct</span><span style="font-family:Verdana;"> claims settlement negatively affected insurance companies’ earned premium. Also, </span><span style="font-family:Verdana;">significant differences in technological and managerial capabilities were </span><span style="font-family:Verdana;">found to exist among the companies, though only one company exhibited this heterogeneity. Besides, there were no policy impacts (or time effect) on vehicle insurance firms’ output in the study period. Policy implications of the results were discussed. 展开更多
关键词 Motor Insurance Premium Earned Claims Settlement Managerial and tech-nological Performance Fixed Effects Regression
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The Research on Competitive Technology Alliance Innovation Risk Formation Mechanism: A Resource-based and Capability-based View
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作者 CHEN Hong CHANG Yu +1 位作者 ZHANG Ding-ning ZHAN An-ling 《International Journal of Plant Engineering and Management》 2013年第2期111-119,共9页
Enterprises engaging in collaboration with competitors can increase their technological diversity and release a new product innovation, but also full of challenges. This complexity of co-opetition relationship require... Enterprises engaging in collaboration with competitors can increase their technological diversity and release a new product innovation, but also full of challenges. This complexity of co-opetition relationship requirements academia and enterprises to clarify the problem of competitive technology alliance risk formation mechanism, making the risk control to dispose. Based on the perspective of resources and capabilities, this paper firstly puts forward the double helix model of alliances' evolution on resources and capabilities ; then, with the deepe- ning of the cooperation, this evolutionary process leads to different innovation risk: opportunism, R and D inte- gration risk and flexible loss risk; next, analyzing the corresponding management path and constructing the conceptual framework of risk management mechanism to help enterprise using the co-opetition relationship to reduce risk and improve the potential competitive advantage. 展开更多
关键词 resource and capability perspective innovation risk generation mechanism the competitive tech-nology alliance
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