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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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Photovoltaic-thermal solar-assisted heat pump systems for building applications:Integration and design methods 被引量:2
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作者 Alessandro Miglioli NiccolòAste +1 位作者 Claudio Del Pero Fabrizio Leonforte 《Energy and Built Environment》 2023年第1期39-56,共18页
The photovoltaic-thermal collector is one of the most interesting technology for solar energy conversion,com-bining electric and thermal energy production in a single device.Vapour-compression heat pump is already con... The photovoltaic-thermal collector is one of the most interesting technology for solar energy conversion,com-bining electric and thermal energy production in a single device.Vapour-compression heat pump is already considered the most suitable clean technology for buildings thermal energy needs.The combination of these two technologies in an integrated“photovoltaic-thermal solar-assisted heat pump”(PVT-SAHP)system allows reaching a high fraction of the building thermal needs covered by renewable energy sources and to improve the performances of both the photovoltaic-thermal collector and the heat pump.The first is cooled down increasing its energy conversion efficiency,while providing low-temperature thermal energy to the second,which benefits from a higher evaporation temperature.The review study presents the state-of-art of photovoltaic-thermal solar-assisted heat pump systems intended to cover thermal energy needs in buildings,with a particular focus on the integration methodologies,the possible configurations,the use of different sources and the design of sub-system components.These issues are addressed by much scientific research,to improve the reliability and applicability of this technology,as an option for the building decarbonization.This study aims to present PVT-SAHP systems in an organic and critical way to propose a useful tool for future research developments.More in detail,the work highlights the fact that the integration of photovoltaic-thermal collectors as evaporator of the heat pump in direct-expansion systems allows the highest heat recovery and performances.However,the distinction of the two circuits lead to more reliable,flexible and robust systems,especially when combined with a second heat source,being able to cover both heating and cooling needs.The implementation of real-time control strategy,as well as the continuous development of the compressor and refrigerant industries is positively influencing this technology,which is receiving more and more attention from scientific research as a suitable solution for nearly zero energy buildings. 展开更多
关键词 Solar-assisted heat pump photovoltaic-thermal collector PVT-SAHP Renewable energy HVAC Technology review
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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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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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Performance analysis of a novel integrated photovoltaic-thermal system by top-surface forced circulation of water 被引量:1
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作者 Md Arman Arefin Mohammad Towhidul Islam +1 位作者 Mohammad Zunaed Khodadad Mostakim 《Clean Energy》 EI 2020年第4期316-327,共12页
Almost 80-90%of energy is wasted as heat(provides no value)in a photovoltaic(PV)panel.An integrated photovoltaic-thermal(PVT)system can utilize this energy and produce electricity simultaneously.In this research,throu... Almost 80-90%of energy is wasted as heat(provides no value)in a photovoltaic(PV)panel.An integrated photovoltaic-thermal(PVT)system can utilize this energy and produce electricity simultaneously.In this research,through energy and exergy analysis,a novel design and methodology of a PVT system are studied and validated.Unlike the common methods,here the collector is located outside the PV panel and connected with pipes.Water passes over the top of the panel and then is forced to the collector by a pump.The effects of different water-mass flow rates on the PV panel and collector,individual and overall efficiency,mass loss,exergetic efficiency are examined experimentally.Results show that the overall efficiency of the system is around five times higher than the individual PV-panel efficiency.The forced circulation of water dropped the panel temperature and increased the panel efficiency by 0.8-1%and exergy by 0.6-1%,where the overall energy efficiency was~81%. 展开更多
关键词 integrated photovoltaic-thermal forced cooling energy analysis exergy analysis flat-plate collector
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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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LINKING CONSTRUCTIVE AND ENERGY INNOVATIONS FOR A NET ZERO-ENERGY BUILDING
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作者 E.Pujadas-Gispert C.C.Korevaar +1 位作者 M.Alsailani S.P.G.Moonen 《Journal of Green Building》 2020年第1期153-184,共32页
This article explains the design,construction and energy strategies of LINQ,a net-zero energy building that was successfully entered into the Solar Decathlon Middle East 2018 held in Dubai.Students of engineering,buil... This article explains the design,construction and energy strategies of LINQ,a net-zero energy building that was successfully entered into the Solar Decathlon Middle East 2018 held in Dubai.Students of engineering,building physics,architecture and urban planning designed,built and operated LINQ.It is mainly powered by solar energy and made of bio-materials.Some of LINQ’s innovations are the ventilated façade with customizable bio-based tiles,the indirect evaporative water cooling system,and the light building integrated photovoltaic-thermal system.LINQ sent more energy to the grid than it drew throughout the competition.However,energy production could have been improved according to simulations and technical specifications.LINQ is a good example of current and future building expectations-combining multiple criteria,strategies,and solutions-to contribute to environmental,social and economic sustainability. 展开更多
关键词 indirect evaporative cooling system bio-based materials building integrated photovoltaic-thermal system solar-powered building thermal mass energy-efficient building Solar Decathlon
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Benchmark assessment of performance indices of a selection of hybrid nanofluids in a hybrid photovoltaic/thermal system
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作者 O.M.Amoo R.O.Fagbenle M.O.Oyewola 《Clean Energy》 EI 2022年第2期247-270,共24页
This research is a study assessing the performance of hybrid nanofluids in hybrid photovoltaic(PV)-thermal systems.This study addresses 10 hybrid nanofluids applied to hybrid PV-thermal systems.The transition to carbo... This research is a study assessing the performance of hybrid nanofluids in hybrid photovoltaic(PV)-thermal systems.This study addresses 10 hybrid nanofluids applied to hybrid PV-thermal systems.The transition to carbon-free energy can mitigate the worst effects of climate change,ensuring that global sustainability is addressed.Clean energy is now responsible for one-third of the global capacity,of which 20%is attributed to solar energy.Renewables continue to be economically viable,with declining costs driving growth.This study aims to compare the yearly performances of a model hybrid PV-thermal system using 10 different hybrid nanofluids.Hybrid nanofluids constitute two or more dissimilar materials stably suspended in a base fluid(e.g.water).MATLAB and COMSOL Multiphysics®computational fluid dynamics software are employed together for the benchmarking assessment with good agreement observed.Various fluid inlet temperatures(Tin∈[300,360]K),nanofluid volume concentrations(φ∈[0,4]%)and storage-tank volumes(V∈[50,300]L)were simulated.The meteorological data applied were those for Lagos,Nigeria(6°27’55.5192”N,3°24’23.2128”E).The assessment based on analytical-numerical solutions reveals that the thermal enhancement by hybrid nanofluids ranges from 6.7%(graphene oxide[GO]-multiwalled carbon nanotube[MWCNT]/water)to 7%(ZnO-Mn-ZnFe2O4/water)forφ=2%and V=300 L.The yearly exergy efficiency ranges from 2.8%(ZnO-Mn-ZnFe2O4/water)to 2.9%(GO-MWCNT/water),also forφ=2%and V=300 L.These findings have implications for a vast range of industrial processes,expanding the knowledge that is critical to a sustainable future. 展开更多
关键词 energy transformation hybrid photovoltaic-thermal(PV/T)system hybrid nanofluids COMSOL Multiphysics® MATLAB ENHANCEMENTS
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