For the dynamic demand assessment of bridge structures under ship impact loading,it may be prudent to adopt analytical models which permit rapid analysis with reasonable accuracy.Herein,a nonlinear dynamic macro-eleme...For the dynamic demand assessment of bridge structures under ship impact loading,it may be prudent to adopt analytical models which permit rapid analysis with reasonable accuracy.Herein,a nonlinear dynamic macro-element is proposed and implemented to quantify the demand of bridge substructures subjected to ship collisions.In the proposed nonlinear macro-element,a combination of an elastic-plastic spring and a dashpot in parallel is employed to describe the mechanical behavior of ship-bows with strain rate effects.Based on the analytical model using the proposed macro-element,a typical substructure under 5000 deadweight tonnage(DWT) ship collision is discussed.Our analyses indicate that the responses of the structure using the nonlinear macro-element agree with the results from the high resolution model,but the efficiency and feasibility of the proposed method increase significantly in practical applications.Furthermore,comparisons between some current design codes(AASHTO,JTGD60-2004,and TB10002.1-2005) and the developed dynamic analysis method suggest that these design codes may be improved,at least to consider the effect of dynamic amplification on structural demand.展开更多
Purpose:The main objective of this work is to show the potentialities of recently developed approaches for automatic knowledge extraction directly from the universities’websites.The information automatically extracte...Purpose:The main objective of this work is to show the potentialities of recently developed approaches for automatic knowledge extraction directly from the universities’websites.The information automatically extracted can be potentially updated with a frequency higher than once per year,and be safe from manipulations or misinterpretations.Moreover,this approach allows us flexibility in collecting indicators about the efficiency of universities’websites and their effectiveness in disseminating key contents.These new indicators can complement traditional indicators of scientific research(e.g.number of articles and number of citations)and teaching(e.g.number of students and graduates)by introducing further dimensions to allow new insights for“profiling”the analyzed universities.Design/methodology/approach:Webometrics relies on web mining methods and techniques to perform quantitative analyses of the web.This study implements an advanced application of the webometric approach,exploiting all the three categories of web mining:web content mining;web structure mining;web usage mining.The information to compute our indicators has been extracted from the universities’websites by using web scraping and text mining techniques.The scraped information has been stored in a NoSQL DB according to a semistructured form to allow for retrieving information efficiently by text mining techniques.This provides increased flexibility in the design of new indicators,opening the door to new types of analyses.Some data have also been collected by means of batch interrogations of search engines(Bing,www.bing.com)or from a leading provider of Web analytics(SimilarWeb,http://www.similarweb.com).The information extracted from the Web has been combined with the University structural information taken from the European Tertiary Education Register(https://eter.joanneum.at/#/home),a database collecting information on Higher Education Institutions(HEIs)at European level.All the above was used to perform a clusterization of 79 Italian universities based on structural and digital indicators.Findings:The main findings of this study concern the evaluation of the potential in digitalization of universities,in particular by presenting techniques for the automatic extraction of information from the web to build indicators of quality and impact of universities’websites.These indicators can complement traditional indicators and can be used to identify groups of universities with common features using clustering techniques working with the above indicators.Research limitations:The results reported in this study refers to Italian universities only,but the approach could be extended to other university systems abroad.Practical implications:The approach proposed in this study and its illustration on Italian universities show the usefulness of recently introduced automatic data extraction and web scraping approaches and its practical relevance for characterizing and profiling the activities of universities on the basis of their websites.The approach could be applied to other university systems.Originality/value:This work applies for the first time to university websites some recently introduced techniques for automatic knowledge extraction based on web scraping,optical character recognition and nontrivial text mining operations(Bruni&Bianchi,2020).展开更多
The human microbiome project（HMP） promoted further understanding of human oral microbes. However, research on the human oral microbiota has not made as much progress as research on the gut microbiota. Currently, the...The human microbiome project（HMP） promoted further understanding of human oral microbes. However, research on the human oral microbiota has not made as much progress as research on the gut microbiota. Currently, the causal relationship between the oral microbiota and oral diseases remains unclear, and little is known about the link between the oral microbiota and human systemic diseases. To further understand the contribution of the oral microbiota in oral diseases and systemic diseases, a Human Oral Microbiome Database（HOMD） was established in the US. The HOMD includes 619 taxa in 13 phyla, and most of the microorganisms are from American populations. Due to individual differences in the microbiome, the HOMD does not reflect the Chinese oral microbial status. Herein, we established a new oral microbiome database—the Oral Microbiome Bank of China（OMBC,http：//www.sklod.org/ombc）. Currently, the OMBC includes information on 289 bacterial strains and 720 clinical samples from the Chinese population, along with lab and clinical information. The OMBC is the first curated description of a Chinese-associated microbiome; it provides tools for use in investigating the role of the oral microbiome in health and diseases, and will give the community abundant data and strain information for future oral microbial studies.展开更多
The most important reference in Italian legislation concerning interventions in favour of people with disabilities came about with Law 104 from February 5th 1992 in which the most important rights for disabled people ...The most important reference in Italian legislation concerning interventions in favour of people with disabilities came about with Law 104 from February 5th 1992 in which the most important rights for disabled people were established. This law led to a new vision,the person with disabilities is no longer seen only a subject needing help but as a person who has the right to live his life in the best possible way that his condition allows him to and thus,it is society's duty and that of the Government,to do everything possible to remove invalidating causes,to promote a disabled person's autonomy and to realise his best social integration possible. To implement what is foreseen by this law it was necessary to activate different important interventions,two of which are very significant:the realisation of Guidelines from the Ministry of Health on rehabilitation activities in which the aims are defined on how rehabilitation should be implemented and how it should be organised on a national level and at a community level. Law 68 from March 12th 1999 decreed the full rights of people with disability to be integrated into the workplace. In the article we will also report some significant data concerning the results of the applications of the law.展开更多
Hydrogen(H_(2))is currently of strategic importance in the pursuit of a decarbonized,environmentally benign,sustainable global energy system;however,the explosive nature of H2 requires leakage monitoring to ensure saf...Hydrogen(H_(2))is currently of strategic importance in the pursuit of a decarbonized,environmentally benign,sustainable global energy system;however,the explosive nature of H2 requires leakage monitoring to ensure safe application in industry.Therefore,H_(2) gas sensors with a high sensitivity and fast response across a wide concentration range are crucial yet technically challenging.In this work,we demonstrate a new type of MEMS differential thermopile gas sensor for the highly sensitive,rapid detection of trace H_(2) gas in air.Facilitated by a unique MiS fabrication technique,pairs of single-crystalline silicon thermopiles(i.e.,sensing and reference thermopiles)are batch fabricated with high-density single-crystalline silicon thermocouples,yielding an outstanding temperature sensitivity at the sub-mK level.Such devices ensure the detection of miniscule temperature changes due to the catalytic reaction of H_(2) with a detection limit as low as~1 ppm at an operating temperature of 120℃.The MEMS differential thermopiles also exhibit a wide linear detection range(1 ppm-2%,more than four orders of magnitude)and fast response and recovery times of 1.9 s and 1.4 s,respectively,when detecting 0.1%H_(2) in air.Moreover,the sensors show good selectivity against common combustible gases and volatile organics,good repeatability,and long-term stability.The proposed MEMS thermopile H_(2) sensors hold promise for the trace detection and early warning of H_(2) leakage in a wide range of application.展开更多
This paper presents a disturbance observer-based linear quadratic Gaussian(LQG)control strategy to stabilize the flexible spacecraft considering the vibration suppression of flexible appendages using an orthogonal clu...This paper presents a disturbance observer-based linear quadratic Gaussian(LQG)control strategy to stabilize the flexible spacecraft considering the vibration suppression of flexible appendages using an orthogonal cluster of magnetically suspended reaction sphere actuators.The nonlinear dynamic equation of a flexible satellite is given and then linearized using the Jacobian method to get a linear state-space model.The dynamic equation of the reaction sphere actuators is derived by considering 2 virtual gimbals.A new steering law is designed to produce the tilt angle commands of orthogonal reaction sphere actuators.The proposed disturbance observer-based LQG considers process disturbances and measurement noises,and performs a trade-off search between control efforts and regulation performance.Numerical simulations are performed to evaluate the proposed strategies for an attitude stabilization scenario,and the results illustrate that the disturbances are effectively mitigated.展开更多
基金supported by the Ministry of Science and Technology of China (No. SLDRCE 09-B-08)the National Natural Science Foundation of China (Nos. 50978194 and 90915011)+1 种基金the Kwang-Hua Fund for College of Civil Engineering,Tongji Universitythe Fund of National Engineering and Research Center for Highways in Mountain Area (No. gsgzj-2010-01),China
文摘For the dynamic demand assessment of bridge structures under ship impact loading,it may be prudent to adopt analytical models which permit rapid analysis with reasonable accuracy.Herein,a nonlinear dynamic macro-element is proposed and implemented to quantify the demand of bridge substructures subjected to ship collisions.In the proposed nonlinear macro-element,a combination of an elastic-plastic spring and a dashpot in parallel is employed to describe the mechanical behavior of ship-bows with strain rate effects.Based on the analytical model using the proposed macro-element,a typical substructure under 5000 deadweight tonnage(DWT) ship collision is discussed.Our analyses indicate that the responses of the structure using the nonlinear macro-element agree with the results from the high resolution model,but the efficiency and feasibility of the proposed method increase significantly in practical applications.Furthermore,comparisons between some current design codes(AASHTO,JTGD60-2004,and TB10002.1-2005) and the developed dynamic analysis method suggest that these design codes may be improved,at least to consider the effect of dynamic amplification on structural demand.
基金This work is developed with the support of the H2020 RISIS 2 Project(No.824091)and of the“Sapienza”Research Awards No.RM1161550376E40E of 2016 and RM11916B8853C925 of 2019.This article is a largely extended version of Bianchi et al.(2019)presented at the ISSI 2019 Conference held in Rome,2–5 September 2019.
文摘Purpose:The main objective of this work is to show the potentialities of recently developed approaches for automatic knowledge extraction directly from the universities’websites.The information automatically extracted can be potentially updated with a frequency higher than once per year,and be safe from manipulations or misinterpretations.Moreover,this approach allows us flexibility in collecting indicators about the efficiency of universities’websites and their effectiveness in disseminating key contents.These new indicators can complement traditional indicators of scientific research(e.g.number of articles and number of citations)and teaching(e.g.number of students and graduates)by introducing further dimensions to allow new insights for“profiling”the analyzed universities.Design/methodology/approach:Webometrics relies on web mining methods and techniques to perform quantitative analyses of the web.This study implements an advanced application of the webometric approach,exploiting all the three categories of web mining:web content mining;web structure mining;web usage mining.The information to compute our indicators has been extracted from the universities’websites by using web scraping and text mining techniques.The scraped information has been stored in a NoSQL DB according to a semistructured form to allow for retrieving information efficiently by text mining techniques.This provides increased flexibility in the design of new indicators,opening the door to new types of analyses.Some data have also been collected by means of batch interrogations of search engines(Bing,www.bing.com)or from a leading provider of Web analytics(SimilarWeb,http://www.similarweb.com).The information extracted from the Web has been combined with the University structural information taken from the European Tertiary Education Register(https://eter.joanneum.at/#/home),a database collecting information on Higher Education Institutions(HEIs)at European level.All the above was used to perform a clusterization of 79 Italian universities based on structural and digital indicators.Findings:The main findings of this study concern the evaluation of the potential in digitalization of universities,in particular by presenting techniques for the automatic extraction of information from the web to build indicators of quality and impact of universities’websites.These indicators can complement traditional indicators and can be used to identify groups of universities with common features using clustering techniques working with the above indicators.Research limitations:The results reported in this study refers to Italian universities only,but the approach could be extended to other university systems abroad.Practical implications:The approach proposed in this study and its illustration on Italian universities show the usefulness of recently introduced automatic data extraction and web scraping approaches and its practical relevance for characterizing and profiling the activities of universities on the basis of their websites.The approach could be applied to other university systems.Originality/value:This work applies for the first time to university websites some recently introduced techniques for automatic knowledge extraction based on web scraping,optical character recognition and nontrivial text mining operations(Bruni&Bianchi,2020).
基金supported by the National Key R&D Program of China(2017YFC0840100 and 2017YFC0840107)the Key Project for Frontier Research of Science and Technology Department of Sichuan Province(2016JY0006 to X.Z.)the National Natural Science Foundation of China(81670978 and 81430011 to X.Z,81470746 and 81772275 to G.L,81700963 to X.P)
文摘The human microbiome project（HMP） promoted further understanding of human oral microbes. However, research on the human oral microbiota has not made as much progress as research on the gut microbiota. Currently, the causal relationship between the oral microbiota and oral diseases remains unclear, and little is known about the link between the oral microbiota and human systemic diseases. To further understand the contribution of the oral microbiota in oral diseases and systemic diseases, a Human Oral Microbiome Database（HOMD） was established in the US. The HOMD includes 619 taxa in 13 phyla, and most of the microorganisms are from American populations. Due to individual differences in the microbiome, the HOMD does not reflect the Chinese oral microbial status. Herein, we established a new oral microbiome database—the Oral Microbiome Bank of China（OMBC,http：//www.sklod.org/ombc）. Currently, the OMBC includes information on 289 bacterial strains and 720 clinical samples from the Chinese population, along with lab and clinical information. The OMBC is the first curated description of a Chinese-associated microbiome; it provides tools for use in investigating the role of the oral microbiome in health and diseases, and will give the community abundant data and strain information for future oral microbial studies.
文摘The most important reference in Italian legislation concerning interventions in favour of people with disabilities came about with Law 104 from February 5th 1992 in which the most important rights for disabled people were established. This law led to a new vision,the person with disabilities is no longer seen only a subject needing help but as a person who has the right to live his life in the best possible way that his condition allows him to and thus,it is society's duty and that of the Government,to do everything possible to remove invalidating causes,to promote a disabled person's autonomy and to realise his best social integration possible. To implement what is foreseen by this law it was necessary to activate different important interventions,two of which are very significant:the realisation of Guidelines from the Ministry of Health on rehabilitation activities in which the aims are defined on how rehabilitation should be implemented and how it should be organised on a national level and at a community level. Law 68 from March 12th 1999 decreed the full rights of people with disability to be integrated into the workplace. In the article we will also report some significant data concerning the results of the applications of the law.
基金support by the National Key R&D Program of China(2021YFB3200800,2021YFB3201302)National Natural Science Foundation of China(61974155,61831021,62104241,62271473,U21A20500)+3 种基金Science and Technology Innovation Plani of Shanghai(19510744600)Scientific Instrument Project of the Chinese Academy of Sciences(YJKYYQ20210024)Shanghai Pujiang Program(20PJ1415600)Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(ZYYCXTD-D-202002,ZYYCXTD-D-202003).
文摘Hydrogen(H_(2))is currently of strategic importance in the pursuit of a decarbonized,environmentally benign,sustainable global energy system;however,the explosive nature of H2 requires leakage monitoring to ensure safe application in industry.Therefore,H_(2) gas sensors with a high sensitivity and fast response across a wide concentration range are crucial yet technically challenging.In this work,we demonstrate a new type of MEMS differential thermopile gas sensor for the highly sensitive,rapid detection of trace H_(2) gas in air.Facilitated by a unique MiS fabrication technique,pairs of single-crystalline silicon thermopiles(i.e.,sensing and reference thermopiles)are batch fabricated with high-density single-crystalline silicon thermocouples,yielding an outstanding temperature sensitivity at the sub-mK level.Such devices ensure the detection of miniscule temperature changes due to the catalytic reaction of H_(2) with a detection limit as low as~1 ppm at an operating temperature of 120℃.The MEMS differential thermopiles also exhibit a wide linear detection range(1 ppm-2%,more than four orders of magnitude)and fast response and recovery times of 1.9 s and 1.4 s,respectively,when detecting 0.1%H_(2) in air.Moreover,the sensors show good selectivity against common combustible gases and volatile organics,good repeatability,and long-term stability.The proposed MEMS thermopile H_(2) sensors hold promise for the trace detection and early warning of H_(2) leakage in a wide range of application.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102174 and 12232011)the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(Nanjing University of Aeronautics and astronautics)(Grant No.MCMS-I-0122K01).
文摘This paper presents a disturbance observer-based linear quadratic Gaussian(LQG)control strategy to stabilize the flexible spacecraft considering the vibration suppression of flexible appendages using an orthogonal cluster of magnetically suspended reaction sphere actuators.The nonlinear dynamic equation of a flexible satellite is given and then linearized using the Jacobian method to get a linear state-space model.The dynamic equation of the reaction sphere actuators is derived by considering 2 virtual gimbals.A new steering law is designed to produce the tilt angle commands of orthogonal reaction sphere actuators.The proposed disturbance observer-based LQG considers process disturbances and measurement noises,and performs a trade-off search between control efforts and regulation performance.Numerical simulations are performed to evaluate the proposed strategies for an attitude stabilization scenario,and the results illustrate that the disturbances are effectively mitigated.
