Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data...Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data that mooring system designers aim to acquire.To address the need for long-term continuous monitoring of mooring tension in deep-sea marine environments,this paper presents a mooring cable tension monitoring method based on the principle of direct mechanical measurement.The developed tension monitoring sensors were installed and applied in the mooring system of the"Yongle"scientific experimental platform.Over the course of one year,a substantial amount of in-situ tension monitoring data was obtained.Under wave heights of up to 1.24 m,the mooring tension on the floating platform reached 16.5 tons.Through frequency domain and time domain analysis,the spectral characteristics of mooring tension,including waveinduced force,slow drift force,and mooring cable elastic restoring force,were determined.The mooring cable elastic restoring force frequency was approximately half of that of the wave signal.Due to the characteristics of the hinge connection structure of the dual module floating platform,under some specific working conditions the wave-induced force was the maximum of the three different frequency forces,and restoring force was the smallest.展开更多
On 20 April 1994,China made its first o!cial full-function connection to the World Wide Web through a 64-kilobyte international leased line,marking the country’s formal entry into the global digital age.The year 2024...On 20 April 1994,China made its first o!cial full-function connection to the World Wide Web through a 64-kilobyte international leased line,marking the country’s formal entry into the global digital age.The year 2024 marked the 30th anniversary of the country’s entry into the internet era.展开更多
Taking the cooperation between China and Pakistan as an example,this paper expounds on the current situation,governance concept,obstacles to cooperation,and differentiated policies of Western countries in the areas of...Taking the cooperation between China and Pakistan as an example,this paper expounds on the current situation,governance concept,obstacles to cooperation,and differentiated policies of Western countries in the areas of cybersecurity,the role of new e-commerce platforms,and digital sovereignty of BRICS countries.It aims to promote inter-governmental cooperation through civil dialogue and lead information technology cooperation among developing countries through the BRICS mechanism,as well as to collaborate to establish guidelines for global cybersecurity,new e-commerce platforms,and digital sovereignty.展开更多
In recent years,gig economy jobs-particularly those of food delivery and ride-hailing drivers-have rapidly emerged as a significant force in the labor market,reflecting the deep integration of China’s digital and rea...In recent years,gig economy jobs-particularly those of food delivery and ride-hailing drivers-have rapidly emerged as a significant force in the labor market,reflecting the deep integration of China’s digital and real economies.This paper examines how digital platforms that support the gig economy exercise directionality and dominance in labor matching,where the platform dictates which consumers workers serve,rather than allowing independent choice.While this platform-led matching may appear to limit consumer and worker autonomy,it actually arises from the platform’s central role in information flow and its technological capabilities,serving as a foundation for the platform’s ability to create large-scale employment through cross-side network effects.Using a theoretical model that integrates digital platforms,labor markets,and product markets,the paper explores how the efficiency of targeted matching affects employment creation.In the early stages of gig economy development,when targeted matching efficiency is low,improvements in assignment efficiency lead to a net increase in gig employment,worker income,and overall social welfare.However,in the later stages,as targeted matching efficiency improves,the potential for monopoly abuse by incumbent platforms may trigger a crowding-out effect,leading to unemployment,income inequality between platforms and workers,and higher commission fees.While fostering competition within platform markets offers benefits,policymakers should avoid excessively low entry barriers,as these can negatively impact incumbent platforms’decisions regarding labor,pricing,and technology investment.展开更多
With the growing importance of wearable and portable electronics in modern society and industry,researchers from all over the world have reported on advances in energy harvesting and self-powered sensing technologies....With the growing importance of wearable and portable electronics in modern society and industry,researchers from all over the world have reported on advances in energy harvesting and self-powered sensing technologies.The current review discusses recent developments in triboelectric platforms from a manufacturing perspective,including material,design,application,and industrialization.Manufacturing is an essential component of both industry and technology.The use of a proper manufacturing process enables cutting-edge technology in a lab-scale stage to progress to commercialization and popularization with scalability,availability,commercial advantage,and consistent quality.Furthermore,much literature has emphasized that the most powerful advantage of the triboelectric platform is its wide range of available materials and simple working mechanism,both of which are important characteristics in manufacturing engineering.As a result,different manufacturing processes can be implemented as needed.Because the practical process can have a synergetic effect on the fundamental development,resulting in the growth of both,the development of the triboelectric platform from the standpoint of manufacturing engineering can be further advanced.However,research into the development of a productive manufacturing process is still in its early stages in the field of triboelectric platforms.This review looks at the various manufacturing technologies used in previous studies and discusses the potential benefits of the appropriate process for triboelectric platforms.Given its unique strength,which includes a diverse material selection and a simple working mechanism,the triboelectric platform can use a variety of manufacturing technologies and the process can be optimized as needed.Numerous research groups have clearly demonstrated the triboelectric platform's advantages.As a result,using appropriate manufacturing processes can accelerate the technological advancement of triboelectric platforms in a variety of research and industrial fields by allowing them to move beyond the lab-scale fabrication stage.展开更多
With the rapid development of the Internet and e-commerce,e-commerce platforms have accumulated huge amounts of user behavior data.The emergence of big data technology provides a powerful means for in-depth analysis o...With the rapid development of the Internet and e-commerce,e-commerce platforms have accumulated huge amounts of user behavior data.The emergence of big data technology provides a powerful means for in-depth analysis of these data and insight into user behavior patterns and preferences.This paper elaborates on the application of big data technology in the analysis of user behavior on e-commerce platforms,including the technical methods of data collection,storage,processing and analysis,as well as the specific applications in the construction of user profiles,precision marketing,personalized recommendation,user retention and churn analysis,etc.,and discusses the challenges and countermeasures faced in the application.Through the study of actual cases,it demonstrates the remarkable effectiveness of big data technology in enhancing the competitiveness of e-commerce platforms and user experience.展开更多
Online learning has taken root and with the advancement in technology more and more educators are embracing online learning.During the COVID-19 pandemic,with total shut down of face-to-face learning,the Kenyan governm...Online learning has taken root and with the advancement in technology more and more educators are embracing online learning.During the COVID-19 pandemic,with total shut down of face-to-face learning,the Kenyan government had moved learning online and remotely.To find out on how learners in remote areas were experiencing learning during the COVID-19 pandemic,a study was carried out using rapid ethnography design.Five final year secondary students were sampled.Data was collected through interviews,observations,and document analysis.This paper reports on the findings of online and remote learning platforms,which were available,accessed,and preferred by the learners in remote areas of Kenya during the pandemic.It also highlights the importance of e-learning platforms in addressing learning experiences and success.展开更多
The purpose of this study is to analyze factors affecting the purchasing behavior of low-income Vietnamese on e-commerce platforms.700 questionnaires were dispersed among universities,coffee shops,and Facebook communi...The purpose of this study is to analyze factors affecting the purchasing behavior of low-income Vietnamese on e-commerce platforms.700 questionnaires were dispersed among universities,coffee shops,and Facebook community groups in Vietnam.Respondents to the questionnaires were consumers of those places in Vietnam,which were randomly selected.Finally,SEM analysis was used on the data to test the hypotheses of the study.The study identified that“Subjective norms”and“Consumer attitudes”have no effect on shopping behavior on e-commerce platforms,while“Perceived behavioral control”is most affected and“Perceived risks”are least affected on shopping behavior.展开更多
This study examined the development of technician teams on large-scale instrument platforms in universities,using the State Key Laboratory of Natural and Biomimetic Drugs in the Peking University School of Pharmaceuti...This study examined the development of technician teams on large-scale instrument platforms in universities,using the State Key Laboratory of Natural and Biomimetic Drugs in the Peking University School of Pharmaceutical Sciences as a case study.Data were collected through questionnaire surveys and interviews conducted in 2017,followed by a questionnaire survey in 2023,offering both subjective and objective insights.The evolution of the platform’s technician team over the past 5 years was analyzed,highlighting key experiences and identifying ongoing challenges.Recommendations to enhance technician team development include recruiting skilled faculty,clearly defining job responsibilities,and refining the assessment and incentive systems.展开更多
To address the widespread challenges of insufficient classroom participation,difficulty maintaining learning interest,and inaccurate learning outcome assessment in existing teaching models,this study introduces a hybr...To address the widespread challenges of insufficient classroom participation,difficulty maintaining learning interest,and inaccurate learning outcome assessment in existing teaching models,this study introduces a hybrid and dual-teacher classroom model.Based on big data and online platforms,this study constructs a music teaching resource system that integrates online micro-lessons,real-time interaction,virtual choirs,collaborative composition,and learning behavior tracking to enhance the openness and personalization of teaching.Through comparative experiments,the study focuses on changes in student knowledge acquisition,musical skills,learning interest,and classroom engagement.Results show that the experimental group significantly outperforms the control group in terms of improvement in knowledge test scores,rhythm and pitch performance,task completion rate,and scores on the learning motivation questionnaire.Differences are particularly prominent in interaction frequency and the expressiveness of the work.The study shows that Group A demonstrates significant improvement in all three dimensions:interest increases from 3.1 to 4.2;autonomous learning motivation increases from 3.0 to 4.1;emotional engagement increases from 3.2 to 4.3,demonstrating strong positive effects.Experimental Group B shows the greatest improvement,with interest increasing from 3.0 to 4.5,autonomous learning motivation from 2.9 to 4.4,and emotional engagement from 3.1 to 4.6,indicating the most significant improvements in learning attitudes and emotions.展开更多
This paper presents an overview of the recent developments in hybrid wind-wave energy.With the focus on floating concepts,the possible configurations introduced in the literature are categorized and depicted,and the m...This paper presents an overview of the recent developments in hybrid wind-wave energy.With the focus on floating concepts,the possible configurations introduced in the literature are categorized and depicted,and the main conclusions obtained from the references are summarized.Moreover,offshore wind and wave resources are discussed in terms of complementarity and supplementarity,offering a new perspective to developing hybrid wind-wave energy systems that look for synergies not limited to maximizing power output.Then,the feasibility of the concepts under development is discussed in detail,with focus on technical feasibility,dynamic feasibility and limitations of the methods employed.The hybrid configurations that surpassed the experimental validation phase are highlighted,and the experimental results are summarized.By compiling more than 40 floating wind turbine concepts,new relations are drawn between power,wind turbine dimensions,platforms’draft and displacement,which are further related to the payload allowance of the units to accommodate wave devices and onboard power take-off systems.Bearing in mind that it is a challenge to model the exact dynamics of hybrid floating wind-wave platforms,this paper elucidates the current research gaps,limitations and future trends in the field.Lastly,based on the overview and topics discussed,several major conclusions are drawn concerning hybrid synergies,dynamics and hydrodynamics of hybrid platforms,feasibility of concepts,among other regards.展开更多
The paper presents an innovative approach to studying the reuse of a decommissioned natural gas production platformfor the seasonal storage and extraction of a hydrogen-methane(H2-CH4)mixture froma depleted reservoir....The paper presents an innovative approach to studying the reuse of a decommissioned natural gas production platformfor the seasonal storage and extraction of a hydrogen-methane(H2-CH4)mixture froma depleted reservoir.The reuse plan involves removing outdated equipment from the platform’s decks while retaining essential components such as wellheads and separators.Exploiting a depleted reservoir for the injection of an H_(2)-CH_(4) mixture requires a thorough understanding of its specific characteristics.This paper focuses on the engineering approach adopted in the basic design phase for such a conversion,providing recommendations and HSE guidelines.Given the hazardous nature of substances like hydrogen in the gas mixture,the paper also examines potential risk scenarios,particularly those involving containment loss.A qualitative and quantitative assessment of these risks is conducted to evaluate their impact on the structure and equipment.The results of this assessment serve as a foundation for later studies on layout optimization and domino effect prevention.Additionally,some critical scenarios are simulated using an innovative approach known as the Source Box Accident Model(SBAM),which was proposed in previous works.SBAM leverages Computational Fluid Dynamics(CFD)but decouples the accidental phenomenon into a release phase and a dispersion phase.This method overcomes the challenges conventional CFD tools face in assessing congested plant configurations,providing more precise estimations of gas cloud behavior.The simulation results indicate that the released gas remains within the platform deck domain,and the flammable cloud is significantly smaller than what traditional,simplified tools predict.展开更多
1.Introduction Due to the continuous progress in surgical methodologies and the swift evolution of surgical tools,minimally invasive procedures have emerged as the dominant approach in urologic oncology surgeries.Nota...1.Introduction Due to the continuous progress in surgical methodologies and the swift evolution of surgical tools,minimally invasive procedures have emerged as the dominant approach in urologic oncology surgeries.Notably,robot-assisted surgery(RAS)has led to its extensive adoption in the surgical management of urinary system tumors due to its enhanced maneuverability,precision in suturing,and anastomotic capabilities.展开更多
In response to the problems of unclear distribution of deep-water pre-salt carbonate reservoirs and formation conditions of large oil fields in the Santos passive continental margin basin,based on comprehensive utiliz...In response to the problems of unclear distribution of deep-water pre-salt carbonate reservoirs and formation conditions of large oil fields in the Santos passive continental margin basin,based on comprehensive utilization of geological,seismic,and core data,and reconstruction of Early Cretaceous prototype basin and lithofacies paleogeography,it is proposed for the first time that the construction of pre-salt carbonate build-ups was controlled by two types of isolated platforms:inter-depression fault-uplift and intra-depression fault-high.The inter-depression fault-uplift isolated platforms are distributed on the present-day pre-salt uplifted zones between depressions,and are built on half-and fault-horst blocks that were inherited and developed in the early intra-continental and inter-continental rift stages.The late intra-continental rift coquinas of the ITP Formation and the early inter-continental rift microbial limestones of the BVE Formation are continuously constructed;intra-depression fault-high isolated platforms are distributed in the current pre-salt depression zones,built on the uplifted zones formed by volcanic rock build-ups in the early prototype stage of intra-continental rifts,and only the BVE microbial limestones are developed.Both types of limestones formed into mound-shoal bodies,that have the characteristics of large reservoir thickness and good physical properties.Based on the dissection of large pre-salt oil fields discovered in the Santos Basin,it has been found that both types of platforms could form large-scale combined structural-stratigraphic traps,surrounded by high-quality lacustrine and lagoon source rocks at the periphery,and efficiently sealed by thick high-quality evaporite rocks above,forming the optimal combination of source,reservoir and cap in the form of“lower generation,middle storage,and upper cap”,with a high degree of oil and gas enrichment.It has been found that the large oil fields are all bottom water massive oil fields with a unified pressure system,and they are all filled to the spill-point.The future exploration is recommended to focus on the inter-depression fault-uplift isolated platforms in the western uplift zone and the southern section of eastern uplift zones,as well as intra-depression fault-high isolated platforms in the central depression zone.The result not only provides an important basis for the advanced selection of potential play fairways,bidding of new blocks,and deployment of awarded exploration blocks in the Santos Basin,but also provides a reference for the global selection of deep-water exploration blocks in passive continental margin basins.展开更多
The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has b...The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has been considered for this purpose,its monitoring accuracy is relatively low.Moreover,the influence of background noise on the dynamic monitoring accuracy of GNSS-PPP remains unclear.Hence,it is imperative to further validate the feasibility of GNSS-PPP for deformation monitoring of offshore platforms.To address these concerns,vibration table tests with different amplitudes and frequencies are conducted.The results demonstrate that GNSS-PPP can effectively monitor horizontal vibration displacement as low as±30 mm,which is consistent with GNSS-RTK.Furthermore,the spectral characteristic of background noise in GNSS-PPP is similar to that of GNSS-RTK(Real Time Kinematic).Building on this observation,an improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)has been proposed to de-noise the data and enhance the dynamic monitoring accuracy of GNSS-PPP.Field monitoring application research is also undertaken,successfully extracting and analyzing the dynamic deformation of an offshore platform structure under environmental excitation using GNSS-PPP monitoring in conjunction with improved CEEMDAN de-noising.By comparing the de-noised dynamic deformation trajectories of the offshore platform during different periods,it is observed that the platform exhibits reversible alternating vibration responses under environmental excitation,with more pronounced displacement deformation in the direction of load action.The research results confirm the feasibility and potential of GNSS-PPP for dynamic deformation monitoring of offshore platforms.展开更多
The outbreak of COVID-19 has drawn great attention around the world.SARS-CoV-2 is a highly infectious virus with occult transmission by many mutations and a long incubation period.In particular,the emergence of asympt...The outbreak of COVID-19 has drawn great attention around the world.SARS-CoV-2 is a highly infectious virus with occult transmission by many mutations and a long incubation period.In particular,the emergence of asymptomatic infections has made the epidemic even more severe.Therefore,early diagnosis and timely management of suspected cases are essential measures to control the spread of the virus.Developing simple,portable,and accurate diagnostic techniques for SARS-CoV-2 is the key to epidemic prevention.The advantages of point-of-care testing technology make it play an increasingly important role in viral detection and screening.This review summarizes the point-of-care testing platforms developed by nucleic acid detection,immunological detection,and nanomaterial-based biosensors detection.Furthermore,this paper provides a prospect for designing future highly accurate,cheap,and convenient SARS-CoV-2 diagnostic technology.展开更多
Public Map Service Platforms(PMSPs)provide embedded map services in domains such as forests and rivers.Users from different domains(Domain Users)prefer specific spatial features,and extracting the Browsing Interests o...Public Map Service Platforms(PMSPs)provide embedded map services in domains such as forests and rivers.Users from different domains(Domain Users)prefer specific spatial features,and extracting the Browsing Interests of Domain Users(BIDUs)can help elucidate users’access intentions and provide suitable recommendations.Previous research has found that access frequency of spatial features is an indicator of users’browsing interests;however,highfrequency spatial features are sparsely distributed,resulting in inaccurate extraction of browsing interests.Our objective is to model the spatial co-occurrence of spatial features and employ BIDUs extraction to address this limitation.First,to extract spatial features in tiles,we proposed a k-nearest neighbor method for Point-of-Interest(POI)extraction and a template-based method for Land Uses/Land Covers extraction.Then,we developed the word2vec model to construct a POI semantic space to quantify spatial co-occurrence and employed multi-domain user classification to verify its effectiveness.Finally,a combined word2vec and singular value decomposition model is proposed to perform topic extraction as a representation of BIDUs.Compared with the baseline models,the proposed model integrates spatial co-occurrence from massive POIs to achieve high-accuracy BIDU extraction.Our findings can help construct domain user profiles and support the development of intelligent PMSPs.展开更多
Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes uncontrollable.PMs remaining permanently in a singularity are beneficial...Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes uncontrollable.PMs remaining permanently in a singularity are beneficial for linearto-rotary motion conversion.Griffis-Duffy(GD)platform is a mobile structure admitting a Bricard motion.In this paper,we present a coordinate-free approach to the design of generalized GD platforms,which consists in determining the shape and attachment of both the moving platform and the fixed base.The generalized GD platform is treated as a combination of six coaxial single-loop mechanisms under the same constraints.Owing to the inversion,hidden in the geometric structure of these single-loop mechanisms,the mapping from a line to a circle establishes the geometric transformation between the fixed base and the moving platform based on the center of inversion,and describes the shape and attachment of the generalized GD platform.Moreover,the center of inversion not only identifies the location of rotation axis,but also affects the shape of the platform mechanism.A graphical construction of generalized GD platforms using inversion,proposed in the paper,provides geometrically feasible solutions of the manipulator design for the requirement of the location of rotation axis.展开更多
In the era of the Internet,various network platforms have evolved into new hubs for information dissemination.Currently,China has established a platform-centered content regulation framework,wherein platforms proactiv...In the era of the Internet,various network platforms have evolved into new hubs for information dissemination.Currently,China has established a platform-centered content regulation framework,wherein platforms proactively enforce content regulations in accordance with legal censorship obligations.Additionally,platform policies and user agreements augment their authority in content regulation.The platforms can achieve cost-effective and highly efficient content regulation by leveraging their strategic advantages enabled by their own technical capabilities and extensive coverage.The platform self-regulation model,however,still faces challenges.First,accurately evaluating content remains a formidable task;second,ensuring effective platform publicity through self-regulation poses difficulties;third,users may potentially face disadvantages due to the platform’s right of self-regulation;and fourth,digital copyright owners face challenges when defending digital copyright disputes under the safe harbor rule.Therefore,it is imperative to establish,review,and revise the legal framework for content regulation of network platforms in order to enhance the efficiency of their governance systems.The formulation of the legal framework for content regulation of network platforms may encompass the following aspects:rationalizing obligations pertaining to platform content regulations,enhancing supervision over platform self-regulation,and establishing a dual-track responsibility system for digital copyright content regulation.This will ensure a harmonious balance among public interests,users’personal rights and interests,and commercial benefits through regulating the content on network platforms.展开更多
The semi-rigid pile-supported composite foundation is widely used in highway projects due to its effectiveness in increasing the bearing capacity and stability of foundations.It is crucial to understand the stress dis...The semi-rigid pile-supported composite foundation is widely used in highway projects due to its effectiveness in increasing the bearing capacity and stability of foundations.It is crucial to understand the stress distribution across the embankment width and the behaviour of unreinforced foundations.Thus,five centrifuge tests were conducted to examine the bearing and deformation behaviours of NPRS(Non-Connected Piled Raft Systems)and GRPS(GeosyntheticReinforced Pile-Supported systems)with varying substratum stiffness,then a comparative analysis was conducted on embankment settlement,pressures underneath the embankments,and axial forces along the piles.The results indicated that greater substratum stiffness correlates with reduced settlement and deformation at various depths.Deformation occurring 5 meters from the embankment toe includes settlement in NPRS and upward movement in GRPS.The potential sliding surface is primarily located within the embankment in NPRS,whereas it may extend through both the embankment and foundation in GRPS.The pile-soil stress ratio and efficiency in NPRS are higher than in GRPS across the embankment.The axial force borne by end-bearing piles is significantly greater than that by floating piles.As the buried depth increases,the axial force in GRPS initially rises then declines,whereas in NPRS,it remains relatively constant within a certain range before decreasing.This study aids in assessing the applicability of composite foundations in complex railway environments and provides a reference for procedural measures under similar conditions.展开更多
文摘Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data that mooring system designers aim to acquire.To address the need for long-term continuous monitoring of mooring tension in deep-sea marine environments,this paper presents a mooring cable tension monitoring method based on the principle of direct mechanical measurement.The developed tension monitoring sensors were installed and applied in the mooring system of the"Yongle"scientific experimental platform.Over the course of one year,a substantial amount of in-situ tension monitoring data was obtained.Under wave heights of up to 1.24 m,the mooring tension on the floating platform reached 16.5 tons.Through frequency domain and time domain analysis,the spectral characteristics of mooring tension,including waveinduced force,slow drift force,and mooring cable elastic restoring force,were determined.The mooring cable elastic restoring force frequency was approximately half of that of the wave signal.Due to the characteristics of the hinge connection structure of the dual module floating platform,under some specific working conditions the wave-induced force was the maximum of the three different frequency forces,and restoring force was the smallest.
文摘On 20 April 1994,China made its first o!cial full-function connection to the World Wide Web through a 64-kilobyte international leased line,marking the country’s formal entry into the global digital age.The year 2024 marked the 30th anniversary of the country’s entry into the internet era.
文摘Taking the cooperation between China and Pakistan as an example,this paper expounds on the current situation,governance concept,obstacles to cooperation,and differentiated policies of Western countries in the areas of cybersecurity,the role of new e-commerce platforms,and digital sovereignty of BRICS countries.It aims to promote inter-governmental cooperation through civil dialogue and lead information technology cooperation among developing countries through the BRICS mechanism,as well as to collaborate to establish guidelines for global cybersecurity,new e-commerce platforms,and digital sovereignty.
基金supported by the National Social Science Fund of China(NSSFC)General Project“Research on the Mechanism of Monopoly Formation and Anti-Monopoly Regulation from the Perspective of Digital Economy”(Grant No.22BJY116)the Guangdong Provincial Natural Science Fund for Distinguished Young Scholars“Research on Carbon Trading Mechanisms under the Generalized Carbon Leakage Risk”(Grant No.2023B1515020068)the National Natural Science Foundation of China(NSFC)Key Project“Research on the Theory,Mechanism and Model of State-Owned Capital Mergers and Acquisitions”(Grant No.72132010).
文摘In recent years,gig economy jobs-particularly those of food delivery and ride-hailing drivers-have rapidly emerged as a significant force in the labor market,reflecting the deep integration of China’s digital and real economies.This paper examines how digital platforms that support the gig economy exercise directionality and dominance in labor matching,where the platform dictates which consumers workers serve,rather than allowing independent choice.While this platform-led matching may appear to limit consumer and worker autonomy,it actually arises from the platform’s central role in information flow and its technological capabilities,serving as a foundation for the platform’s ability to create large-scale employment through cross-side network effects.Using a theoretical model that integrates digital platforms,labor markets,and product markets,the paper explores how the efficiency of targeted matching affects employment creation.In the early stages of gig economy development,when targeted matching efficiency is low,improvements in assignment efficiency lead to a net increase in gig employment,worker income,and overall social welfare.However,in the later stages,as targeted matching efficiency improves,the potential for monopoly abuse by incumbent platforms may trigger a crowding-out effect,leading to unemployment,income inequality between platforms and workers,and higher commission fees.While fostering competition within platform markets offers benefits,policymakers should avoid excessively low entry barriers,as these can negatively impact incumbent platforms’decisions regarding labor,pricing,and technology investment.
基金supported by the National Research Foundation of Korea(NRF)(No.2021R1C1C2009703)supported by the National Research Foundation of Korea(NRF)Grant funded by the Korea government(MSIT)(RS-2024-00344920)supported by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)Grant funded by the Ministry of Trade,Industry and Energy of Korea(No.RS2023-00244330)。
文摘With the growing importance of wearable and portable electronics in modern society and industry,researchers from all over the world have reported on advances in energy harvesting and self-powered sensing technologies.The current review discusses recent developments in triboelectric platforms from a manufacturing perspective,including material,design,application,and industrialization.Manufacturing is an essential component of both industry and technology.The use of a proper manufacturing process enables cutting-edge technology in a lab-scale stage to progress to commercialization and popularization with scalability,availability,commercial advantage,and consistent quality.Furthermore,much literature has emphasized that the most powerful advantage of the triboelectric platform is its wide range of available materials and simple working mechanism,both of which are important characteristics in manufacturing engineering.As a result,different manufacturing processes can be implemented as needed.Because the practical process can have a synergetic effect on the fundamental development,resulting in the growth of both,the development of the triboelectric platform from the standpoint of manufacturing engineering can be further advanced.However,research into the development of a productive manufacturing process is still in its early stages in the field of triboelectric platforms.This review looks at the various manufacturing technologies used in previous studies and discusses the potential benefits of the appropriate process for triboelectric platforms.Given its unique strength,which includes a diverse material selection and a simple working mechanism,the triboelectric platform can use a variety of manufacturing technologies and the process can be optimized as needed.Numerous research groups have clearly demonstrated the triboelectric platform's advantages.As a result,using appropriate manufacturing processes can accelerate the technological advancement of triboelectric platforms in a variety of research and industrial fields by allowing them to move beyond the lab-scale fabrication stage.
文摘With the rapid development of the Internet and e-commerce,e-commerce platforms have accumulated huge amounts of user behavior data.The emergence of big data technology provides a powerful means for in-depth analysis of these data and insight into user behavior patterns and preferences.This paper elaborates on the application of big data technology in the analysis of user behavior on e-commerce platforms,including the technical methods of data collection,storage,processing and analysis,as well as the specific applications in the construction of user profiles,precision marketing,personalized recommendation,user retention and churn analysis,etc.,and discusses the challenges and countermeasures faced in the application.Through the study of actual cases,it demonstrates the remarkable effectiveness of big data technology in enhancing the competitiveness of e-commerce platforms and user experience.
文摘Online learning has taken root and with the advancement in technology more and more educators are embracing online learning.During the COVID-19 pandemic,with total shut down of face-to-face learning,the Kenyan government had moved learning online and remotely.To find out on how learners in remote areas were experiencing learning during the COVID-19 pandemic,a study was carried out using rapid ethnography design.Five final year secondary students were sampled.Data was collected through interviews,observations,and document analysis.This paper reports on the findings of online and remote learning platforms,which were available,accessed,and preferred by the learners in remote areas of Kenya during the pandemic.It also highlights the importance of e-learning platforms in addressing learning experiences and success.
文摘The purpose of this study is to analyze factors affecting the purchasing behavior of low-income Vietnamese on e-commerce platforms.700 questionnaires were dispersed among universities,coffee shops,and Facebook community groups in Vietnam.Respondents to the questionnaires were consumers of those places in Vietnam,which were randomly selected.Finally,SEM analysis was used on the data to test the hypotheses of the study.The study identified that“Subjective norms”and“Consumer attitudes”have no effect on shopping behavior on e-commerce platforms,while“Perceived behavioral control”is most affected and“Perceived risks”are least affected on shopping behavior.
文摘This study examined the development of technician teams on large-scale instrument platforms in universities,using the State Key Laboratory of Natural and Biomimetic Drugs in the Peking University School of Pharmaceutical Sciences as a case study.Data were collected through questionnaire surveys and interviews conducted in 2017,followed by a questionnaire survey in 2023,offering both subjective and objective insights.The evolution of the platform’s technician team over the past 5 years was analyzed,highlighting key experiences and identifying ongoing challenges.Recommendations to enhance technician team development include recruiting skilled faculty,clearly defining job responsibilities,and refining the assessment and incentive systems.
文摘To address the widespread challenges of insufficient classroom participation,difficulty maintaining learning interest,and inaccurate learning outcome assessment in existing teaching models,this study introduces a hybrid and dual-teacher classroom model.Based on big data and online platforms,this study constructs a music teaching resource system that integrates online micro-lessons,real-time interaction,virtual choirs,collaborative composition,and learning behavior tracking to enhance the openness and personalization of teaching.Through comparative experiments,the study focuses on changes in student knowledge acquisition,musical skills,learning interest,and classroom engagement.Results show that the experimental group significantly outperforms the control group in terms of improvement in knowledge test scores,rhythm and pitch performance,task completion rate,and scores on the learning motivation questionnaire.Differences are particularly prominent in interaction frequency and the expressiveness of the work.The study shows that Group A demonstrates significant improvement in all three dimensions:interest increases from 3.1 to 4.2;autonomous learning motivation increases from 3.0 to 4.1;emotional engagement increases from 3.2 to 4.3,demonstrating strong positive effects.Experimental Group B shows the greatest improvement,with interest increasing from 3.0 to 4.5,autonomous learning motivation from 2.9 to 4.4,and emotional engagement from 3.1 to 4.6,indicating the most significant improvements in learning attitudes and emotions.
基金supported by the Portuguese Foundation for Science and Technology(Fundação para a Ciência e Tecnologia-FCT)it contributes to the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineering(Grant No.UIDB/UIDP/00134/2020)funded the first author for his PhD Scholarship(Grant No.SFRH/BD/145602/2019).
文摘This paper presents an overview of the recent developments in hybrid wind-wave energy.With the focus on floating concepts,the possible configurations introduced in the literature are categorized and depicted,and the main conclusions obtained from the references are summarized.Moreover,offshore wind and wave resources are discussed in terms of complementarity and supplementarity,offering a new perspective to developing hybrid wind-wave energy systems that look for synergies not limited to maximizing power output.Then,the feasibility of the concepts under development is discussed in detail,with focus on technical feasibility,dynamic feasibility and limitations of the methods employed.The hybrid configurations that surpassed the experimental validation phase are highlighted,and the experimental results are summarized.By compiling more than 40 floating wind turbine concepts,new relations are drawn between power,wind turbine dimensions,platforms’draft and displacement,which are further related to the payload allowance of the units to accommodate wave devices and onboard power take-off systems.Bearing in mind that it is a challenge to model the exact dynamics of hybrid floating wind-wave platforms,this paper elucidates the current research gaps,limitations and future trends in the field.Lastly,based on the overview and topics discussed,several major conclusions are drawn concerning hybrid synergies,dynamics and hydrodynamics of hybrid platforms,feasibility of concepts,among other regards.
基金funded by the Italian Ministry of Environment and Energy Security(MASE)-Direzione Generale per le Fonti energetiche e Titoli Abilitativi(DGFTA).
文摘The paper presents an innovative approach to studying the reuse of a decommissioned natural gas production platformfor the seasonal storage and extraction of a hydrogen-methane(H2-CH4)mixture froma depleted reservoir.The reuse plan involves removing outdated equipment from the platform’s decks while retaining essential components such as wellheads and separators.Exploiting a depleted reservoir for the injection of an H_(2)-CH_(4) mixture requires a thorough understanding of its specific characteristics.This paper focuses on the engineering approach adopted in the basic design phase for such a conversion,providing recommendations and HSE guidelines.Given the hazardous nature of substances like hydrogen in the gas mixture,the paper also examines potential risk scenarios,particularly those involving containment loss.A qualitative and quantitative assessment of these risks is conducted to evaluate their impact on the structure and equipment.The results of this assessment serve as a foundation for later studies on layout optimization and domino effect prevention.Additionally,some critical scenarios are simulated using an innovative approach known as the Source Box Accident Model(SBAM),which was proposed in previous works.SBAM leverages Computational Fluid Dynamics(CFD)but decouples the accidental phenomenon into a release phase and a dispersion phase.This method overcomes the challenges conventional CFD tools face in assessing congested plant configurations,providing more precise estimations of gas cloud behavior.The simulation results indicate that the released gas remains within the platform deck domain,and the flammable cloud is significantly smaller than what traditional,simplified tools predict.
基金supported by grants from the National Natural Science Foundation of China(No.82172741 to Ye D)Shanghai Municipal Health Bureau(No.2020CXJQ03 to Ye D)Xuhui District Hospital Local Cooperation Project(No.23XHYD-14 to Ye D).
文摘1.Introduction Due to the continuous progress in surgical methodologies and the swift evolution of surgical tools,minimally invasive procedures have emerged as the dominant approach in urologic oncology surgeries.Notably,robot-assisted surgery(RAS)has led to its extensive adoption in the surgical management of urinary system tumors due to its enhanced maneuverability,precision in suturing,and anastomotic capabilities.
基金Supported by the National Science and Technology Major Project(2016ZX05029001)CNPC Science and Technology Project(2019D-4310)。
文摘In response to the problems of unclear distribution of deep-water pre-salt carbonate reservoirs and formation conditions of large oil fields in the Santos passive continental margin basin,based on comprehensive utilization of geological,seismic,and core data,and reconstruction of Early Cretaceous prototype basin and lithofacies paleogeography,it is proposed for the first time that the construction of pre-salt carbonate build-ups was controlled by two types of isolated platforms:inter-depression fault-uplift and intra-depression fault-high.The inter-depression fault-uplift isolated platforms are distributed on the present-day pre-salt uplifted zones between depressions,and are built on half-and fault-horst blocks that were inherited and developed in the early intra-continental and inter-continental rift stages.The late intra-continental rift coquinas of the ITP Formation and the early inter-continental rift microbial limestones of the BVE Formation are continuously constructed;intra-depression fault-high isolated platforms are distributed in the current pre-salt depression zones,built on the uplifted zones formed by volcanic rock build-ups in the early prototype stage of intra-continental rifts,and only the BVE microbial limestones are developed.Both types of limestones formed into mound-shoal bodies,that have the characteristics of large reservoir thickness and good physical properties.Based on the dissection of large pre-salt oil fields discovered in the Santos Basin,it has been found that both types of platforms could form large-scale combined structural-stratigraphic traps,surrounded by high-quality lacustrine and lagoon source rocks at the periphery,and efficiently sealed by thick high-quality evaporite rocks above,forming the optimal combination of source,reservoir and cap in the form of“lower generation,middle storage,and upper cap”,with a high degree of oil and gas enrichment.It has been found that the large oil fields are all bottom water massive oil fields with a unified pressure system,and they are all filled to the spill-point.The future exploration is recommended to focus on the inter-depression fault-uplift isolated platforms in the western uplift zone and the southern section of eastern uplift zones,as well as intra-depression fault-high isolated platforms in the central depression zone.The result not only provides an important basis for the advanced selection of potential play fairways,bidding of new blocks,and deployment of awarded exploration blocks in the Santos Basin,but also provides a reference for the global selection of deep-water exploration blocks in passive continental margin basins.
基金financially supported by the National Key R&D Program of China(Grant No.2022YFB4200705)the National Natural Science Foundation of China(Grant No.52109146)。
文摘The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has been considered for this purpose,its monitoring accuracy is relatively low.Moreover,the influence of background noise on the dynamic monitoring accuracy of GNSS-PPP remains unclear.Hence,it is imperative to further validate the feasibility of GNSS-PPP for deformation monitoring of offshore platforms.To address these concerns,vibration table tests with different amplitudes and frequencies are conducted.The results demonstrate that GNSS-PPP can effectively monitor horizontal vibration displacement as low as±30 mm,which is consistent with GNSS-RTK.Furthermore,the spectral characteristic of background noise in GNSS-PPP is similar to that of GNSS-RTK(Real Time Kinematic).Building on this observation,an improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)has been proposed to de-noise the data and enhance the dynamic monitoring accuracy of GNSS-PPP.Field monitoring application research is also undertaken,successfully extracting and analyzing the dynamic deformation of an offshore platform structure under environmental excitation using GNSS-PPP monitoring in conjunction with improved CEEMDAN de-noising.By comparing the de-noised dynamic deformation trajectories of the offshore platform during different periods,it is observed that the platform exhibits reversible alternating vibration responses under environmental excitation,with more pronounced displacement deformation in the direction of load action.The research results confirm the feasibility and potential of GNSS-PPP for dynamic deformation monitoring of offshore platforms.
基金supported by the National Key R&D Program of China(No.2021YFC2301100)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB30000000)+3 种基金the National Natural Science Foundation of China(No.61890940)the Chongqing Bayu Scholar Program(No.DP2020036)Program of Shanghai Academic Research Leaders(No.23XD1420200)Fudan University。
文摘The outbreak of COVID-19 has drawn great attention around the world.SARS-CoV-2 is a highly infectious virus with occult transmission by many mutations and a long incubation period.In particular,the emergence of asymptomatic infections has made the epidemic even more severe.Therefore,early diagnosis and timely management of suspected cases are essential measures to control the spread of the virus.Developing simple,portable,and accurate diagnostic techniques for SARS-CoV-2 is the key to epidemic prevention.The advantages of point-of-care testing technology make it play an increasingly important role in viral detection and screening.This review summarizes the point-of-care testing platforms developed by nucleic acid detection,immunological detection,and nanomaterial-based biosensors detection.Furthermore,this paper provides a prospect for designing future highly accurate,cheap,and convenient SARS-CoV-2 diagnostic technology.
基金supported by the National Natural Science Foundation of China[grant numbers:U20A209141771426]Zhizhuo Research Fund on Spatial-Temporal Artificial Intelligence[grant number ZZJJ202204]LIESMARS Special Research Funding.
文摘Public Map Service Platforms(PMSPs)provide embedded map services in domains such as forests and rivers.Users from different domains(Domain Users)prefer specific spatial features,and extracting the Browsing Interests of Domain Users(BIDUs)can help elucidate users’access intentions and provide suitable recommendations.Previous research has found that access frequency of spatial features is an indicator of users’browsing interests;however,highfrequency spatial features are sparsely distributed,resulting in inaccurate extraction of browsing interests.Our objective is to model the spatial co-occurrence of spatial features and employ BIDUs extraction to address this limitation.First,to extract spatial features in tiles,we proposed a k-nearest neighbor method for Point-of-Interest(POI)extraction and a template-based method for Land Uses/Land Covers extraction.Then,we developed the word2vec model to construct a POI semantic space to quantify spatial co-occurrence and employed multi-domain user classification to verify its effectiveness.Finally,a combined word2vec and singular value decomposition model is proposed to perform topic extraction as a representation of BIDUs.Compared with the baseline models,the proposed model integrates spatial co-occurrence from massive POIs to achieve high-accuracy BIDU extraction.Our findings can help construct domain user profiles and support the development of intelligent PMSPs.
基金Supported by National Natural Science Foundation of China (Grant Nos.U1813221,52075015)Personnel Startup Project of Zhejiang A&F University Scientific Research Development Foundation of China (Grant No.2024LFR015)。
文摘Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes uncontrollable.PMs remaining permanently in a singularity are beneficial for linearto-rotary motion conversion.Griffis-Duffy(GD)platform is a mobile structure admitting a Bricard motion.In this paper,we present a coordinate-free approach to the design of generalized GD platforms,which consists in determining the shape and attachment of both the moving platform and the fixed base.The generalized GD platform is treated as a combination of six coaxial single-loop mechanisms under the same constraints.Owing to the inversion,hidden in the geometric structure of these single-loop mechanisms,the mapping from a line to a circle establishes the geometric transformation between the fixed base and the moving platform based on the center of inversion,and describes the shape and attachment of the generalized GD platform.Moreover,the center of inversion not only identifies the location of rotation axis,but also affects the shape of the platform mechanism.A graphical construction of generalized GD platforms using inversion,proposed in the paper,provides geometrically feasible solutions of the manipulator design for the requirement of the location of rotation axis.
基金This paper is a phased achievement of the key project of the Chongqing Municipal Education Commission entitled“Research on Establishment of Regional Legal Framework for Rural Revitalization”(Project No.23SKJD033)the university-level project of Southwest University of Political Science&Law entitled“A Comparative Study on Legislation for Agricultural and Rural Modernization”(Project No.DFLF2020Y12).
文摘In the era of the Internet,various network platforms have evolved into new hubs for information dissemination.Currently,China has established a platform-centered content regulation framework,wherein platforms proactively enforce content regulations in accordance with legal censorship obligations.Additionally,platform policies and user agreements augment their authority in content regulation.The platforms can achieve cost-effective and highly efficient content regulation by leveraging their strategic advantages enabled by their own technical capabilities and extensive coverage.The platform self-regulation model,however,still faces challenges.First,accurately evaluating content remains a formidable task;second,ensuring effective platform publicity through self-regulation poses difficulties;third,users may potentially face disadvantages due to the platform’s right of self-regulation;and fourth,digital copyright owners face challenges when defending digital copyright disputes under the safe harbor rule.Therefore,it is imperative to establish,review,and revise the legal framework for content regulation of network platforms in order to enhance the efficiency of their governance systems.The formulation of the legal framework for content regulation of network platforms may encompass the following aspects:rationalizing obligations pertaining to platform content regulations,enhancing supervision over platform self-regulation,and establishing a dual-track responsibility system for digital copyright content regulation.This will ensure a harmonious balance among public interests,users’personal rights and interests,and commercial benefits through regulating the content on network platforms.
基金financially supported by the National Natural Science Foundation of China(Nos.51878577 and 52378463)the Natural Science Foundation of Shandong Provincial,China(No.ZR2022ME042)the School-Enterprise Cooperation Program of China Railway 14th Bureau Group Co.(QTHT-HGLCHSD-00052)。
文摘The semi-rigid pile-supported composite foundation is widely used in highway projects due to its effectiveness in increasing the bearing capacity and stability of foundations.It is crucial to understand the stress distribution across the embankment width and the behaviour of unreinforced foundations.Thus,five centrifuge tests were conducted to examine the bearing and deformation behaviours of NPRS(Non-Connected Piled Raft Systems)and GRPS(GeosyntheticReinforced Pile-Supported systems)with varying substratum stiffness,then a comparative analysis was conducted on embankment settlement,pressures underneath the embankments,and axial forces along the piles.The results indicated that greater substratum stiffness correlates with reduced settlement and deformation at various depths.Deformation occurring 5 meters from the embankment toe includes settlement in NPRS and upward movement in GRPS.The potential sliding surface is primarily located within the embankment in NPRS,whereas it may extend through both the embankment and foundation in GRPS.The pile-soil stress ratio and efficiency in NPRS are higher than in GRPS across the embankment.The axial force borne by end-bearing piles is significantly greater than that by floating piles.As the buried depth increases,the axial force in GRPS initially rises then declines,whereas in NPRS,it remains relatively constant within a certain range before decreasing.This study aids in assessing the applicability of composite foundations in complex railway environments and provides a reference for procedural measures under similar conditions.
