In view of some problems existing in traditional software crowdsourcing tests and Internet of Things device tests, we developed a CrowdIoT crowdsourcing test system for the Internet of Things devices based on a block ...In view of some problems existing in traditional software crowdsourcing tests and Internet of Things device tests, we developed a CrowdIoT crowdsourcing test system for the Internet of Things devices based on a block chain. CrowdIoT uses the core technology of blockchain to focus its testing on physical devices on the Internet of Things. CrowdIoT uses two different testing methods for different testing needs: online testing and offline testing. Online remote testing is our key function and research object. By opening the testing interface of Internet of Things devices to testers, testers can test the devices in the CrowdIoT system interface without having to get the hardware. At the same time, CrowdIoT introduced multi-threaded parallel testing technology to solve the conflict problem of multiple testers competing for hardware resources in online testing. Offline testing, as a supplement to online testing, is to send Internet of Things devices to testers with high credibility in deposit guarantee, so that testers can fully test the hardware devices and dig out as many vulnerabilities of the devices as possible. CrowdIoT has its own complete and scientific credibility system, combined with relevant incentive mechanism, consensus mechanism and connection mechanism, which not only effectively solves the centralization problem existing in traditional crowdsourcing testing platforms, but also solves the pain point of the lack of remote testing of Internet of Things devices in the market. Then it solves the problems of equipment limitation and testing cost limits in the field of Internet of Things equipment testing, and provides a platform for security testing and use for the Internet of Things participants.展开更多
In the mobile crowdsensing of vehicular ad hoc networks (VANETs), in order to improve the amount of data collection, an effective method to attract a large number of vehicles is needed. Therefore, the incentive mechan...In the mobile crowdsensing of vehicular ad hoc networks (VANETs), in order to improve the amount of data collection, an effective method to attract a large number of vehicles is needed. Therefore, the incentive mechanism plays a dominant role in the mobile crowdsensing of vehicular ad hoc networks. In addition, the behavior of providing malicious data by vehicles as data collectors will have a huge negative impact on the whole collection process. Therefore, participants need to be encouraged to provide data honestly to obtain more available data. In order to increase data collection and improve the availability of collected data, this paper proposes an incentive mechanism for mobile crowdsensing in vehicular ad hoc networks named V-IMCS. Specifically, the Stackelberg game model, Lloyd’s clustering algorithm and reputation management mechanism are used to balance the competitive relationship between participants and process the data according to the priority order, so as to improve the amount of data collection and encourage participants to honestly provide data to obtain more available data. In addition, the effectiveness of the proposed mechanism is verified by a series of simulations. The simulation results show that the amount of available data is significantly higher than the existing incentive mechanism while improving the amount of data collection.展开更多
Layered double hydroxides (LDHs), a class of anionic clays consisting of brucite-like host layers and interlayer anions, have been widely investigated in the last decade due to their promising applications in many are...Layered double hydroxides (LDHs), a class of anionic clays consisting of brucite-like host layers and interlayer anions, have been widely investigated in the last decade due to their promising applications in many areas such as catalysis, ion separation and adsorption. Owing to the highly tunable compositi on and uniform distribution of metal cations in the brucite-like layers, as well as the facile exchangeability of intercalated anions, LDHs can be modified and functionalized to form various nanostructures/composites through versatile processes such as anion intercalation and exfoliation, decoration of nanoparticles, selfassembly with other two-dimensional (2D) materials, and controlled growth on conductive supports (e.g., nanowire arrays, nano tubes, 3D foams). In this article, we briefly review the recent advances on both the LDH nano structures and functionalized composites toward the applications in energy conversion, especially for water oxidation.展开更多
In this paper we consider the contextual multi-armed bandit problem for linear payoffs under a risk-averse criterion.At each round,contexts are revealed for each arm,and the decision maker chooses one arm to pull and ...In this paper we consider the contextual multi-armed bandit problem for linear payoffs under a risk-averse criterion.At each round,contexts are revealed for each arm,and the decision maker chooses one arm to pull and receives the corresponding reward.In particular,we consider mean-variance as the risk criterion,and the best arm is the one with the largest mean-variance reward.We apply the Thompson sampling algorithm for the disjoint model,and provide a comprehensive regret analysis for a variant of the proposed algorithm.For T rounds,K actions,and d-dimensional feature vectors,we prove a regret bound of O((1+ρ+1/ρ)d In T ln K/δ√dKT^(1+2∈)ln K/δ1/e)that holds with probability 1-δunder the mean-variance criterion with risk tolerance p,for any 0<ε<1/2,0<δ<1.The empirical performance of our proposed algorithms is demonstrated via a portfolio selection problem.展开更多
A calculation method for the friction coefficient and meshing efficiency of plastic line gear(LG)pair under dry friction conditions was studied theoretically and experimentally,taking a polyoxymethylene parallel line ...A calculation method for the friction coefficient and meshing efficiency of plastic line gear(LG)pair under dry friction conditions was studied theoretically and experimentally,taking a polyoxymethylene parallel line gear pair(POM PLGP)as an example.Firstly,the geometric and mechanical models of PLGP were built by considering the effects of misalignment and loaded deformation under the actual operating condition.Then,the friction coefficient of POM specimens was obtained via the ball-on-disk experiment,of which the value varies between 0.35 and 0.45 under the experimental conditions.The calculation formula for the friction coefficient of POM LG pair was obtained by fitting the friction coefficient of the POM specimens,and the meshing efficiency of POM LG pair was calculated based on the calculation formula for friction coefficient and the meshing efficiency calculation approach.Finally,the meshing efficiency of POM PLGP specimens was measured using a homemade gear meshing efficiency test rig.The experimental results validated the feasibility of the proposed calculation method for the friction coefficient and meshing efficiency of the plastic LG pair.This study provides a method for the calculation of the friction coefficient and meshing efficiency of plastic gear pairs under dry friction conditions.It also provides the basis for the wear calculation of plastic LG pair under dry friction conditions.展开更多
Mucosal vaccines have risen to prominence in the corona virus disease 2019(COVID-19)pandemic due to their ability to elicit both local antibody and tissue-resident T cell responses,affording a dual-layered defense aga...Mucosal vaccines have risen to prominence in the corona virus disease 2019(COVID-19)pandemic due to their ability to elicit both local antibody and tissue-resident T cell responses,affording a dual-layered defense against infection and transmission at respiratory entry sites.While intramuscular vaccines predominantly focus on systemic immunity,mucosal vaccines offer a more nuanced,site-specific approach.However,the field faces a dearth of mucosal vaccine options for respiratory diseases,starkly contrasting to the extensive array of well-characterized injectable vaccines.The unique features of mucosal surfaces necessitate specialized adjuvants and delivery systems,adding complexity to adapting injectable vaccine technologies for mucosal applications.Here,we review the recent insights into the specificities of respiratory mucosal immunology that provide a foundation for future innovations besides the emerging vaccine platforms,newly discovered adjuvants,and vaccine delivery systems,which may open promising avenues for developing mucosal vaccines targeting respiratory pathogens.展开更多
文摘In view of some problems existing in traditional software crowdsourcing tests and Internet of Things device tests, we developed a CrowdIoT crowdsourcing test system for the Internet of Things devices based on a block chain. CrowdIoT uses the core technology of blockchain to focus its testing on physical devices on the Internet of Things. CrowdIoT uses two different testing methods for different testing needs: online testing and offline testing. Online remote testing is our key function and research object. By opening the testing interface of Internet of Things devices to testers, testers can test the devices in the CrowdIoT system interface without having to get the hardware. At the same time, CrowdIoT introduced multi-threaded parallel testing technology to solve the conflict problem of multiple testers competing for hardware resources in online testing. Offline testing, as a supplement to online testing, is to send Internet of Things devices to testers with high credibility in deposit guarantee, so that testers can fully test the hardware devices and dig out as many vulnerabilities of the devices as possible. CrowdIoT has its own complete and scientific credibility system, combined with relevant incentive mechanism, consensus mechanism and connection mechanism, which not only effectively solves the centralization problem existing in traditional crowdsourcing testing platforms, but also solves the pain point of the lack of remote testing of Internet of Things devices in the market. Then it solves the problems of equipment limitation and testing cost limits in the field of Internet of Things equipment testing, and provides a platform for security testing and use for the Internet of Things participants.
文摘In the mobile crowdsensing of vehicular ad hoc networks (VANETs), in order to improve the amount of data collection, an effective method to attract a large number of vehicles is needed. Therefore, the incentive mechanism plays a dominant role in the mobile crowdsensing of vehicular ad hoc networks. In addition, the behavior of providing malicious data by vehicles as data collectors will have a huge negative impact on the whole collection process. Therefore, participants need to be encouraged to provide data honestly to obtain more available data. In order to increase data collection and improve the availability of collected data, this paper proposes an incentive mechanism for mobile crowdsensing in vehicular ad hoc networks named V-IMCS. Specifically, the Stackelberg game model, Lloyd’s clustering algorithm and reputation management mechanism are used to balance the competitive relationship between participants and process the data according to the priority order, so as to improve the amount of data collection and encourage participants to honestly provide data to obtain more available data. In addition, the effectiveness of the proposed mechanism is verified by a series of simulations. The simulation results show that the amount of available data is significantly higher than the existing incentive mechanism while improving the amount of data collection.
基金supported by the National Natural Science Foundation of China(Grant Nos.21505050,51672109)the Dispatch of Faculty Abroad of the University of Jinan+2 种基金the Natural Science Foundation of Shandong Province(Grant No.ZR2016FM30)supported in part by the WPI-MANA,Ministry of Education,Culture,Sports,Science and Technology,Japansupport from JSPS KAKENNHI(18H03869)
文摘Layered double hydroxides (LDHs), a class of anionic clays consisting of brucite-like host layers and interlayer anions, have been widely investigated in the last decade due to their promising applications in many areas such as catalysis, ion separation and adsorption. Owing to the highly tunable compositi on and uniform distribution of metal cations in the brucite-like layers, as well as the facile exchangeability of intercalated anions, LDHs can be modified and functionalized to form various nanostructures/composites through versatile processes such as anion intercalation and exfoliation, decoration of nanoparticles, selfassembly with other two-dimensional (2D) materials, and controlled growth on conductive supports (e.g., nanowire arrays, nano tubes, 3D foams). In this article, we briefly review the recent advances on both the LDH nano structures and functionalized composites toward the applications in energy conversion, especially for water oxidation.
基金support by the Air Force Office of Scientific Research under Grant FA9550-19-1-0283 and Grant FA9550-22-1-0244National Science Foundation under Grant DMS2053489.
文摘In this paper we consider the contextual multi-armed bandit problem for linear payoffs under a risk-averse criterion.At each round,contexts are revealed for each arm,and the decision maker chooses one arm to pull and receives the corresponding reward.In particular,we consider mean-variance as the risk criterion,and the best arm is the one with the largest mean-variance reward.We apply the Thompson sampling algorithm for the disjoint model,and provide a comprehensive regret analysis for a variant of the proposed algorithm.For T rounds,K actions,and d-dimensional feature vectors,we prove a regret bound of O((1+ρ+1/ρ)d In T ln K/δ√dKT^(1+2∈)ln K/δ1/e)that holds with probability 1-δunder the mean-variance criterion with risk tolerance p,for any 0<ε<1/2,0<δ<1.The empirical performance of our proposed algorithms is demonstrated via a portfolio selection problem.
基金The authors gratefully acknowledge the support from the National Natural Science Foundation of China(No.51575191)2019 Guangzhou Technology Project(No.201904010368).
文摘A calculation method for the friction coefficient and meshing efficiency of plastic line gear(LG)pair under dry friction conditions was studied theoretically and experimentally,taking a polyoxymethylene parallel line gear pair(POM PLGP)as an example.Firstly,the geometric and mechanical models of PLGP were built by considering the effects of misalignment and loaded deformation under the actual operating condition.Then,the friction coefficient of POM specimens was obtained via the ball-on-disk experiment,of which the value varies between 0.35 and 0.45 under the experimental conditions.The calculation formula for the friction coefficient of POM LG pair was obtained by fitting the friction coefficient of the POM specimens,and the meshing efficiency of POM LG pair was calculated based on the calculation formula for friction coefficient and the meshing efficiency calculation approach.Finally,the meshing efficiency of POM PLGP specimens was measured using a homemade gear meshing efficiency test rig.The experimental results validated the feasibility of the proposed calculation method for the friction coefficient and meshing efficiency of the plastic LG pair.This study provides a method for the calculation of the friction coefficient and meshing efficiency of plastic gear pairs under dry friction conditions.It also provides the basis for the wear calculation of plastic LG pair under dry friction conditions.
基金funded by the Emergency Key Program of Guangzhou Laboratory (grant No.EKPG21-21 to Hua Peng).
文摘Mucosal vaccines have risen to prominence in the corona virus disease 2019(COVID-19)pandemic due to their ability to elicit both local antibody and tissue-resident T cell responses,affording a dual-layered defense against infection and transmission at respiratory entry sites.While intramuscular vaccines predominantly focus on systemic immunity,mucosal vaccines offer a more nuanced,site-specific approach.However,the field faces a dearth of mucosal vaccine options for respiratory diseases,starkly contrasting to the extensive array of well-characterized injectable vaccines.The unique features of mucosal surfaces necessitate specialized adjuvants and delivery systems,adding complexity to adapting injectable vaccine technologies for mucosal applications.Here,we review the recent insights into the specificities of respiratory mucosal immunology that provide a foundation for future innovations besides the emerging vaccine platforms,newly discovered adjuvants,and vaccine delivery systems,which may open promising avenues for developing mucosal vaccines targeting respiratory pathogens.
