The productivity of medical staff within a polyclinic is not an easy task due to the multiple activities that physicians must perform at the same time: not only healthcare for patients, but also academic activities, s...The productivity of medical staff within a polyclinic is not an easy task due to the multiple activities that physicians must perform at the same time: not only healthcare for patients, but also academic activities, such as scientific research and teaching. Hybrid professionals are healthcare professionals who have to play multiple roles, often not precisely identified. This analysis examines the case study of the University Polyclinic of Messina (Italy) where three university departments and 7 Dipartimenti di Attività Integrate (DAI) are distinguished and physicians (both professors and researchers) are called to reconcile multiple tasks. Given the distinction between university departments and DAIs, the aim of this contribution is to identify the organizational elements that prove to be predictors of scientific efficiency and productivity. To what extent does the inclusion in a DAI or within a university department affect individual incentives? A new dataset is built for the present research containing information on University Polyclinic of Messina physicians (full professors, associate professors, researchers). From the Scopus online database (<a href="https://www.scopus.com/home.uri">https://www.scopus.com/home.uri</a>) individual information relating to the number of publications, the number of citations, h-index was obtained. The latter is used to assess the quality of individual research;in order to evaluate the teaching activity, the number of hours dedicated to didactical activities is taken into account, together with the number of teaching hours required by one’s role. Information related to remuneration and the circumstance of carrying out intramural activities has also been included. A thorough statistical analysis is carried out and the individual groups (DAI and university departments) are compared through the Kruskal Wallis test. Estimating a Poisson Gamma mixture model highlights those variables that are significant predictors of scientific productivity. Attention paid to organizational metho展开更多
Hybrid metal matrix composites (Hmmc) are found to be more superior than the conventional composite materials because of their improved mechanical properties, which can be suited for an extensive range of engineering ...Hybrid metal matrix composites (Hmmc) are found to be more superior than the conventional composite materials because of their improved mechanical properties, which can be suited for an extensive range of engineering applications. Automobile and aerospace industries widely make use of hybrid composites as they possess excellent corrosion, wear resistance, low density, and high strength. This paper displays the strategy to build the hybrid composite utilizing Stir casting Method. Present investigation includes the creation of composites utilizing boron carbide (2%, 4%, 6% volume) and Red mud (2% volume) as the reinforcements and Structural aluminium as the matrix. Experimental investigation of wear analysis of the composites was carried out according to the L9 Taguchi method. The designated number of experiments was accomplished to probe the impact of control factors on the specific wear rate (SWR) of the developed composites. ANOVA was carried out and Wt%. Reinforcement was found to be the decisive factor on the SWR of the developed hybrid composite. The Confirmatory test was successfully carried out and the computed error was found to be varying from 0.878% to 2.58%.展开更多
Some types of renewable energy have been experiencing rapid evolution in recent decades, notably among the energies associated with the oceans, such as wave and current energies. The development of new energy conversi...Some types of renewable energy have been experiencing rapid evolution in recent decades, notably among the energies associated with the oceans, such as wave and current energies. The development of new energy conversion technologies for these two forms of energy has been offering a large number of equipment configurations and plant geometries for energy conversion. This process can be implemented aiming at the result of feasibility studies in places with energy potentials, establishing minimum feasibility limits to be reached. This work aims to contribute in this sense with a feasibility study of a system with ocean wave power plants and with socio-current power plants to be operated on the southern coast of Brazil. This study evaluates a hybrid system with contributions from energy supplies obtained from wave plants and current plants, connected to the grid and supplying the demand of the municipalities in the North Coast region of the State of Rio Grande do Sul, the southernmost state of Brazil. The study was carried out with simulations with the Homer Legacy software, with some adaptations for the simulation of ocean wave plants and ocean current plants. The results indicate that the ocean wave power plants were viable in the vast majority of simulated scenarios, while the ocean current power plants were viable in the scenarios with more intense average ocean current speeds and with more expensive energy acquired from the interconnected system.展开更多
Model updating issues with high-dimensional and strong-nonlinear optimization processes are still unsolved by most optimization methods.In this study,a hybrid methodology that combines the Gaussian-white-noise-mutatio...Model updating issues with high-dimensional and strong-nonlinear optimization processes are still unsolved by most optimization methods.In this study,a hybrid methodology that combines the Gaussian-white-noise-mutation particle swarm optimization(GMPSO),back-propagation neural network(BPNN)and Latin hypercube sampling(LHS)technique is proposed.In this approach,as a meta-heuristic algorithm with the least modification to the standard PSO,GMPSO simultaneously offers convenient programming and good performance in optimization.The BPNN with LHS establishes the meta-models for FEM to accelerate efficiency during the updating process.A case study of the model updating of an actual bridge with no distribution but bounded parameters was carried out using this methodology with two different objective functions.One considers only the frequencies of the main girder and the other considers both the frequencies and vertical displacements of typical points.The updating results show that the methodology is a sound approach to solve an actual complex bridge structure and offers good agreement in the frequencies and mode shapes of the updated model and test data.Based on the shape comparison of the main girder at the finished state with different objective functions,it is emphasized that both the dynamic and static responses should be taken into consideration during the model updating process.展开更多
Summer and winter campaigns for the chemical compositions and sources of nonmethane hydrocarbons(NMHCs)and oxygenated volatile organic compounds(OVOCs)were conducted in Xi’an.Data from 57 photochemical assessment mon...Summer and winter campaigns for the chemical compositions and sources of nonmethane hydrocarbons(NMHCs)and oxygenated volatile organic compounds(OVOCs)were conducted in Xi’an.Data from 57 photochemical assessment monitoring stations for NMHCs and 20 OVOC species were analyzed.Significant seasonal differences were noted for total VOC(TVOC,NMHCs and OVOCs)concentrations and compositions.The campaign-average TVOC concentrations in winter(85.3±60.6 ppbv)were almost twice those in summer(47.2±31.6 ppbv).Alkanes and OVOCs were the most abundant category in winter and summer,respectively.NMHCs,but not OVOCs,had significantly higher levels on weekends than on weekdays.Total ozone formation potential was higher in summer than in winter(by 50%)because of the high concentrations of alkenes(particularly isoprene),high temperature,and high solar radiation levels in summer.The Hybrid Environmental Receptor Model(HERM)was used to conduct source apportionment for atmospheric TVOCs in winter and summer,with excellent accuracy.HERM demonstrated its suitability in a situation where only partial source profile data were available.The HERM results indicated significantly different seasonal source contributions to TVOCs in Xi’an.In particular,coal and biomass burning had contributions greater than half in winter(53.4%),whereas traffic sources were prevalent in summer(53.1%).This study’s results highlight the need for targeted and adjustable VOC control measures that account for seasonal differences in Xi’an;such measures should target not only the severe problem with VOC pollution but also the problem of consequent secondary pollution(e.g.,from ozone and secondary organic aerosols).展开更多
The outbreak of novel coronavirus(COVID-19)attracted worldwide attention.It has posed a significant challenge for the global economies,especially the healthcare sector.Even with a robust healthcare system,countries we...The outbreak of novel coronavirus(COVID-19)attracted worldwide attention.It has posed a significant challenge for the global economies,especially the healthcare sector.Even with a robust healthcare system,countries were not prepared for the ramifications of COVID-19.Several statistical,dynamic,and mathematical models of the COVID-19 outbreak including the SEIR model have been developed to analyze the infection its transmission dynamics.The objective of this research is to use public data to study the properties associated with the COVID-19 pandemic to develop a dynamic hybrid model based on SEIRD and ascertainment rate with automatically selected parameters.The proposed model consists of two parts:the modified SEIRD dynamic model and ARIMA models.We fit SEIRD model parameters against historical values of infected,recovered and deceased population divided by ascertainment rate,which,in turn,is also a parameter of the model.Residuals of the first model for infected,recovered,and deceased populations are then corrected using ARIMA models.The model can analyze the input data in real-time and provide long-and short-term forecasts with confidence intervals.The model was tested and validated on the US COVID statistics dataset from the COVID Tracking Project.For validation,we use unseen recent statistical data.We use five common measures to estimate model prediction ability:MAE,MSE,MLSE,Normalized MAE,and Normalized MSE.We proved a great model ability to make accurate predictions of infected,recovered,and deceased patients.The output of the model can be used by the government,private sectors,and policymakers to reduce health and economic risks significantly improved consumer credit scoring.展开更多
High-performance and low-cost sodium-ion capacitors(SICs)show tremendous potential applications in public transport and grid energy storage.However,conventional SICs are limited by the low specific capacity,poor rate ...High-performance and low-cost sodium-ion capacitors(SICs)show tremendous potential applications in public transport and grid energy storage.However,conventional SICs are limited by the low specific capacity,poor rate capability,and low initial coulombic efficiency(ICE)of anode materials.Herein,we report layered iron vanadate(Fe5V15O39(OH)9·9H2O)ultrathin nanosheets with a thickness of~2.2 nm(FeVO UNSs)as a novel anode for rapid and reversible sodium-ion storage.According to in situ synchrotron X-ray diffractions and electrochemical analysis,the storage mechanism of FeVO UNSs anode is Na+intercalation pseudocapacitance under a safe potential window.The FeVO UNSs anode delivers high ICE(93.86%),high reversible capacity(292 mAh g^−1),excellent cycling stability,and remarkable rate capability.Furthermore,a pseudocapacitor–battery hybrid SIC(PBH-SIC)consisting of pseudocapacitor-type FeVO UNSs anode and battery-type Na3(VO)2(PO4)2F cathode is assembled with the elimination of presodiation treatments.The PBH-SIC involves faradaic reaction on both cathode and anode materials,delivering a high energy density of 126 Wh kg^−1 at 91 W kg^−1,a high power density of 7.6 kW kg^−1 with an energy density of 43 Wh kg−1,and 9000 stable cycles.The tunable vanadate materials with high-performance Na+intercalation pseudocapacitance provide a direction for developing next-generation highenergy capacitors.展开更多
Wearable self-powered systems integrated with energy conversion and storage devices such as solar-charging power units arouse widespread concerns in scientific and industrial realms.However,their applications are hamp...Wearable self-powered systems integrated with energy conversion and storage devices such as solar-charging power units arouse widespread concerns in scientific and industrial realms.However,their applications are hampered by the restrictions of unbefitting size matching between integrated modules,limited tolerance to the variation of input current,reliability,and safety issues.Herein,flexible solar-charging self-powered units based on printed Zn-ion hybrid micro-capacitor as the energy storage module is developed.Unique 3D micro-/nano-architecture of the biomass kelp-carbon combined with multivalent ion(Zn2+)storage endows the aqueous Zn-ion hybrid capacitor with high specific capacity(196.7 mAh g^−1 at 0.1 A g^−1).By employing an in-plane asymmetric printing technique,the fabricated quasi-solid-state Zn-ion hybrid microcapacitors exhibit high rate,long life and energy density up to 8.2μWh cm^−2.After integrating the micro-capacitor with organic solar cells,the derived self-powered system presents outstanding energy conversion/storage efficiency(ηoverall=17.8%),solar-charging cyclic stability(95%after 100 cycles),wide current tolerance,and good mechanical flexibility.Such portable,wearable,and green integrated units offer new insights into design of advanced self-powered systems toward the goal of developing highly safe,economic,stable,and long-life smart wearable electronics.展开更多
With the development of the Internet,technology,and means of communication,the production of tourist data has multiplied at all levels(hotels,restaurants,transport,heritage,tourist events,activities,etc.),especially w...With the development of the Internet,technology,and means of communication,the production of tourist data has multiplied at all levels(hotels,restaurants,transport,heritage,tourist events,activities,etc.),especially with the development of Online Travel Agency(OTA).However,the list of possibilities offered to tourists by these Web search engines(or even specialized tourist sites)can be overwhelming and relevant results are usually drowned in informational"noise",which prevents,or at least slows down the selection process.To assist tourists in trip planning and help them to find the information they are looking for,many recommender systems have been developed.In this article,we present an overview of the various recommendation approaches used in the field of tourism.From this study,an architecture and a conceptual framework for tourism recommender system are proposed,based on a hybrid recommendation approach.The proposed system goes beyond the recommendation of a list of tourist attractions,tailored to tourist preferences.It can be seen as a trip planner that designs a detailed program,including heterogeneous tourism resources,for a specific visit duration.The ultimate goal is to develop a recommender system based on big data technologies,artificial intelligence,and operational research to promote tourism in Morocco,specifically in the Daraa-Tafilalet region.展开更多
In this study,we extend traditional(single-target)hybrid systems to multi-target hybrid systems with a focus on the multi-maneuvering-target tracking system.This system consists of a continuous state,a discrete and sw...In this study,we extend traditional(single-target)hybrid systems to multi-target hybrid systems with a focus on the multi-maneuvering-target tracking system.This system consists of a continuous state,a discrete and switchable state,and a discrete,time-constant,and unique state.By defining a new generalized labeled multi-Bernoulli density,we prove that it is closed under the Chapman-Kolmogorov prediction and Bayes update for multi-target hybrid systems.In other words,we provide the exact derivation of a solution to this system,i.e.,the multi-model generalized labeled multi-Bemoulli filter,which has been developed without strict proof.展开更多
The low catalytic efficiency of redox-active cofactor photoregeneration severely limits the performance of photoenzymatic hybrid systems. Herein, we synthesized thiophene-conjugated porous C3N4 nanosheets(CN-ATCN) exh...The low catalytic efficiency of redox-active cofactor photoregeneration severely limits the performance of photoenzymatic hybrid systems. Herein, we synthesized thiophene-conjugated porous C3N4 nanosheets(CN-ATCN) exhibiting boosted photoregeneration activity of nicotinamide cofactors(NADH and NADPH), which are the most common redox cofactors of oxidoreductases, with regeneration rates of 59.00 μM/min for NADH and 40.99 μM/min for NADPH, ~ 84.3 and 24.7 times higher than those of bulk g-C3N4, respectively. The thin nanosheet structure of CN-ATCN facilitates the exposure of active sites to reactants and favors the diff usion of reactants and products. Upon conjugation of a thiophene moiety into the carbon nitride framework, the optical and photoelectric properties of CN-ATCN were considerably enhanced by an extended π-conjugation system in the frameworks and molecular type II heterojunctions formed between the incorporated and nonincorporated portions of CN-ATCN. Upon coupling NAD(P)H photoregeneration reaction by CN-ATCN with NAD(P)H-dependent enzymatic systems, sustainable synthesis of L-tert-leucine and styrene oxide was achieved with rates of 964 and 14.9 μM/h, respectively.展开更多
文摘The productivity of medical staff within a polyclinic is not an easy task due to the multiple activities that physicians must perform at the same time: not only healthcare for patients, but also academic activities, such as scientific research and teaching. Hybrid professionals are healthcare professionals who have to play multiple roles, often not precisely identified. This analysis examines the case study of the University Polyclinic of Messina (Italy) where three university departments and 7 Dipartimenti di Attività Integrate (DAI) are distinguished and physicians (both professors and researchers) are called to reconcile multiple tasks. Given the distinction between university departments and DAIs, the aim of this contribution is to identify the organizational elements that prove to be predictors of scientific efficiency and productivity. To what extent does the inclusion in a DAI or within a university department affect individual incentives? A new dataset is built for the present research containing information on University Polyclinic of Messina physicians (full professors, associate professors, researchers). From the Scopus online database (<a href="https://www.scopus.com/home.uri">https://www.scopus.com/home.uri</a>) individual information relating to the number of publications, the number of citations, h-index was obtained. The latter is used to assess the quality of individual research;in order to evaluate the teaching activity, the number of hours dedicated to didactical activities is taken into account, together with the number of teaching hours required by one’s role. Information related to remuneration and the circumstance of carrying out intramural activities has also been included. A thorough statistical analysis is carried out and the individual groups (DAI and university departments) are compared through the Kruskal Wallis test. Estimating a Poisson Gamma mixture model highlights those variables that are significant predictors of scientific productivity. Attention paid to organizational metho
文摘Hybrid metal matrix composites (Hmmc) are found to be more superior than the conventional composite materials because of their improved mechanical properties, which can be suited for an extensive range of engineering applications. Automobile and aerospace industries widely make use of hybrid composites as they possess excellent corrosion, wear resistance, low density, and high strength. This paper displays the strategy to build the hybrid composite utilizing Stir casting Method. Present investigation includes the creation of composites utilizing boron carbide (2%, 4%, 6% volume) and Red mud (2% volume) as the reinforcements and Structural aluminium as the matrix. Experimental investigation of wear analysis of the composites was carried out according to the L9 Taguchi method. The designated number of experiments was accomplished to probe the impact of control factors on the specific wear rate (SWR) of the developed composites. ANOVA was carried out and Wt%. Reinforcement was found to be the decisive factor on the SWR of the developed hybrid composite. The Confirmatory test was successfully carried out and the computed error was found to be varying from 0.878% to 2.58%.
文摘Some types of renewable energy have been experiencing rapid evolution in recent decades, notably among the energies associated with the oceans, such as wave and current energies. The development of new energy conversion technologies for these two forms of energy has been offering a large number of equipment configurations and plant geometries for energy conversion. This process can be implemented aiming at the result of feasibility studies in places with energy potentials, establishing minimum feasibility limits to be reached. This work aims to contribute in this sense with a feasibility study of a system with ocean wave power plants and with socio-current power plants to be operated on the southern coast of Brazil. This study evaluates a hybrid system with contributions from energy supplies obtained from wave plants and current plants, connected to the grid and supplying the demand of the municipalities in the North Coast region of the State of Rio Grande do Sul, the southernmost state of Brazil. The study was carried out with simulations with the Homer Legacy software, with some adaptations for the simulation of ocean wave plants and ocean current plants. The results indicate that the ocean wave power plants were viable in the vast majority of simulated scenarios, while the ocean current power plants were viable in the scenarios with more intense average ocean current speeds and with more expensive energy acquired from the interconnected system.
基金National Natural Science Foundation of China under Grant No.51438002the research fund of Jiangsu Province Key Laboratory of Structure Engineering,China under Grant No.ZD1803+3 种基金Natural Science Foundation of Suzhou University of Science and Technology under Grant No.XKQ2018008Natural Science Foundation of Jiangsu Higher Education Institutions of China under Grant No.19KJB560021Science and Technology Project of Jiangsu Construction System under Grant No.2020ZD07Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Model updating issues with high-dimensional and strong-nonlinear optimization processes are still unsolved by most optimization methods.In this study,a hybrid methodology that combines the Gaussian-white-noise-mutation particle swarm optimization(GMPSO),back-propagation neural network(BPNN)and Latin hypercube sampling(LHS)technique is proposed.In this approach,as a meta-heuristic algorithm with the least modification to the standard PSO,GMPSO simultaneously offers convenient programming and good performance in optimization.The BPNN with LHS establishes the meta-models for FEM to accelerate efficiency during the updating process.A case study of the model updating of an actual bridge with no distribution but bounded parameters was carried out using this methodology with two different objective functions.One considers only the frequencies of the main girder and the other considers both the frequencies and vertical displacements of typical points.The updating results show that the methodology is a sound approach to solve an actual complex bridge structure and offers good agreement in the frequencies and mode shapes of the updated model and test data.Based on the shape comparison of the main girder at the finished state with different objective functions,it is emphasized that both the dynamic and static responses should be taken into consideration during the model updating process.
基金This research was supported by the Natural Science Foundation of China(Grant No.41907188)Natural Science Foundation of Shaanxi Province,China(Grant No.2019JQ-386)the China Postdoctoral Science Foundation(Grant No.2019M653658).
文摘Summer and winter campaigns for the chemical compositions and sources of nonmethane hydrocarbons(NMHCs)and oxygenated volatile organic compounds(OVOCs)were conducted in Xi’an.Data from 57 photochemical assessment monitoring stations for NMHCs and 20 OVOC species were analyzed.Significant seasonal differences were noted for total VOC(TVOC,NMHCs and OVOCs)concentrations and compositions.The campaign-average TVOC concentrations in winter(85.3±60.6 ppbv)were almost twice those in summer(47.2±31.6 ppbv).Alkanes and OVOCs were the most abundant category in winter and summer,respectively.NMHCs,but not OVOCs,had significantly higher levels on weekends than on weekdays.Total ozone formation potential was higher in summer than in winter(by 50%)because of the high concentrations of alkenes(particularly isoprene),high temperature,and high solar radiation levels in summer.The Hybrid Environmental Receptor Model(HERM)was used to conduct source apportionment for atmospheric TVOCs in winter and summer,with excellent accuracy.HERM demonstrated its suitability in a situation where only partial source profile data were available.The HERM results indicated significantly different seasonal source contributions to TVOCs in Xi’an.In particular,coal and biomass burning had contributions greater than half in winter(53.4%),whereas traffic sources were prevalent in summer(53.1%).This study’s results highlight the need for targeted and adjustable VOC control measures that account for seasonal differences in Xi’an;such measures should target not only the severe problem with VOC pollution but also the problem of consequent secondary pollution(e.g.,from ozone and secondary organic aerosols).
文摘The outbreak of novel coronavirus(COVID-19)attracted worldwide attention.It has posed a significant challenge for the global economies,especially the healthcare sector.Even with a robust healthcare system,countries were not prepared for the ramifications of COVID-19.Several statistical,dynamic,and mathematical models of the COVID-19 outbreak including the SEIR model have been developed to analyze the infection its transmission dynamics.The objective of this research is to use public data to study the properties associated with the COVID-19 pandemic to develop a dynamic hybrid model based on SEIRD and ascertainment rate with automatically selected parameters.The proposed model consists of two parts:the modified SEIRD dynamic model and ARIMA models.We fit SEIRD model parameters against historical values of infected,recovered and deceased population divided by ascertainment rate,which,in turn,is also a parameter of the model.Residuals of the first model for infected,recovered,and deceased populations are then corrected using ARIMA models.The model can analyze the input data in real-time and provide long-and short-term forecasts with confidence intervals.The model was tested and validated on the US COVID statistics dataset from the COVID Tracking Project.For validation,we use unseen recent statistical data.We use five common measures to estimate model prediction ability:MAE,MSE,MLSE,Normalized MAE,and Normalized MSE.We proved a great model ability to make accurate predictions of infected,recovered,and deceased patients.The output of the model can be used by the government,private sectors,and policymakers to reduce health and economic risks significantly improved consumer credit scoring.
基金This work was financially supported by the National Natural Science Foundation of China(No.22005256)the National Key R&D Program of China(Grant No.2016YFA0202600)the Natural Science Foundation of Fujian Province of China(No.2020J01034).
文摘High-performance and low-cost sodium-ion capacitors(SICs)show tremendous potential applications in public transport and grid energy storage.However,conventional SICs are limited by the low specific capacity,poor rate capability,and low initial coulombic efficiency(ICE)of anode materials.Herein,we report layered iron vanadate(Fe5V15O39(OH)9·9H2O)ultrathin nanosheets with a thickness of~2.2 nm(FeVO UNSs)as a novel anode for rapid and reversible sodium-ion storage.According to in situ synchrotron X-ray diffractions and electrochemical analysis,the storage mechanism of FeVO UNSs anode is Na+intercalation pseudocapacitance under a safe potential window.The FeVO UNSs anode delivers high ICE(93.86%),high reversible capacity(292 mAh g^−1),excellent cycling stability,and remarkable rate capability.Furthermore,a pseudocapacitor–battery hybrid SIC(PBH-SIC)consisting of pseudocapacitor-type FeVO UNSs anode and battery-type Na3(VO)2(PO4)2F cathode is assembled with the elimination of presodiation treatments.The PBH-SIC involves faradaic reaction on both cathode and anode materials,delivering a high energy density of 126 Wh kg^−1 at 91 W kg^−1,a high power density of 7.6 kW kg^−1 with an energy density of 43 Wh kg−1,and 9000 stable cycles.The tunable vanadate materials with high-performance Na+intercalation pseudocapacitance provide a direction for developing next-generation highenergy capacitors.
基金the National Natural Science Foundation of Hubei Province(Grant No.2019CFB110)the fund of the Shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials(Grant No.1-KF-2019).
文摘Wearable self-powered systems integrated with energy conversion and storage devices such as solar-charging power units arouse widespread concerns in scientific and industrial realms.However,their applications are hampered by the restrictions of unbefitting size matching between integrated modules,limited tolerance to the variation of input current,reliability,and safety issues.Herein,flexible solar-charging self-powered units based on printed Zn-ion hybrid micro-capacitor as the energy storage module is developed.Unique 3D micro-/nano-architecture of the biomass kelp-carbon combined with multivalent ion(Zn2+)storage endows the aqueous Zn-ion hybrid capacitor with high specific capacity(196.7 mAh g^−1 at 0.1 A g^−1).By employing an in-plane asymmetric printing technique,the fabricated quasi-solid-state Zn-ion hybrid microcapacitors exhibit high rate,long life and energy density up to 8.2μWh cm^−2.After integrating the micro-capacitor with organic solar cells,the derived self-powered system presents outstanding energy conversion/storage efficiency(ηoverall=17.8%),solar-charging cyclic stability(95%after 100 cycles),wide current tolerance,and good mechanical flexibility.Such portable,wearable,and green integrated units offer new insights into design of advanced self-powered systems toward the goal of developing highly safe,economic,stable,and long-life smart wearable electronics.
文摘With the development of the Internet,technology,and means of communication,the production of tourist data has multiplied at all levels(hotels,restaurants,transport,heritage,tourist events,activities,etc.),especially with the development of Online Travel Agency(OTA).However,the list of possibilities offered to tourists by these Web search engines(or even specialized tourist sites)can be overwhelming and relevant results are usually drowned in informational"noise",which prevents,or at least slows down the selection process.To assist tourists in trip planning and help them to find the information they are looking for,many recommender systems have been developed.In this article,we present an overview of the various recommendation approaches used in the field of tourism.From this study,an architecture and a conceptual framework for tourism recommender system are proposed,based on a hybrid recommendation approach.The proposed system goes beyond the recommendation of a list of tourist attractions,tailored to tourist preferences.It can be seen as a trip planner that designs a detailed program,including heterogeneous tourism resources,for a specific visit duration.The ultimate goal is to develop a recommender system based on big data technologies,artificial intelligence,and operational research to promote tourism in Morocco,specifically in the Daraa-Tafilalet region.
基金Project supported by the National Natural Science Foundation of China(No.61601510)the Young Talent Support Project of China Association for Science and Technology(No.18-JCJQ-QT-008)。
文摘In this study,we extend traditional(single-target)hybrid systems to multi-target hybrid systems with a focus on the multi-maneuvering-target tracking system.This system consists of a continuous state,a discrete and switchable state,and a discrete,time-constant,and unique state.By defining a new generalized labeled multi-Bernoulli density,we prove that it is closed under the Chapman-Kolmogorov prediction and Bayes update for multi-target hybrid systems.In other words,we provide the exact derivation of a solution to this system,i.e.,the multi-model generalized labeled multi-Bemoulli filter,which has been developed without strict proof.
基金supported by the National Key Research and Development Program of China(No.2018YFA0901300)the National Natural Science Foundation of China(No.NSFC 21621004)。
文摘The low catalytic efficiency of redox-active cofactor photoregeneration severely limits the performance of photoenzymatic hybrid systems. Herein, we synthesized thiophene-conjugated porous C3N4 nanosheets(CN-ATCN) exhibiting boosted photoregeneration activity of nicotinamide cofactors(NADH and NADPH), which are the most common redox cofactors of oxidoreductases, with regeneration rates of 59.00 μM/min for NADH and 40.99 μM/min for NADPH, ~ 84.3 and 24.7 times higher than those of bulk g-C3N4, respectively. The thin nanosheet structure of CN-ATCN facilitates the exposure of active sites to reactants and favors the diff usion of reactants and products. Upon conjugation of a thiophene moiety into the carbon nitride framework, the optical and photoelectric properties of CN-ATCN were considerably enhanced by an extended π-conjugation system in the frameworks and molecular type II heterojunctions formed between the incorporated and nonincorporated portions of CN-ATCN. Upon coupling NAD(P)H photoregeneration reaction by CN-ATCN with NAD(P)H-dependent enzymatic systems, sustainable synthesis of L-tert-leucine and styrene oxide was achieved with rates of 964 and 14.9 μM/h, respectively.