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Enhancing Multicriteria-Based Recommendations by Alleviating Scalability and Sparsity Issues Using Collaborative Denoising Autoencoder
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作者 S.Abinaya K.Uttej Kumar 《Computers, Materials & Continua》 SCIE EI 2024年第2期2269-2286,共18页
A Recommender System(RS)is a crucial part of several firms,particularly those involved in e-commerce.In conventional RS,a user may only offer a single rating for an item-that is insufficient to perceive consumer prefe... A Recommender System(RS)is a crucial part of several firms,particularly those involved in e-commerce.In conventional RS,a user may only offer a single rating for an item-that is insufficient to perceive consumer preferences.Nowadays,businesses in industries like e-learning and tourism enable customers to rate a product using a variety of factors to comprehend customers’preferences.On the other hand,the collaborative filtering(CF)algorithm utilizing AutoEncoder(AE)is seen to be effective in identifying user-interested items.However,the cost of these computations increases nonlinearly as the number of items and users increases.To triumph over the issues,a novel expanded stacked autoencoder(ESAE)with Kernel Fuzzy C-Means Clustering(KFCM)technique is proposed with two phases.In the first phase of offline,the sparse multicriteria rating matrix is smoothened to a complete matrix by predicting the users’intact rating by the ESAE approach and users are clustered using the KFCM approach.In the next phase of online,the top-N recommendation prediction is made by the ESAE approach involving only the most similar user from multiple clusters.Hence the ESAE_KFCM model upgrades the prediction accuracy of 98.2%in Top-N recommendation with a minimized recommendation generation time.An experimental check on the Yahoo!Movies(YM)movie dataset and TripAdvisor(TA)travel dataset confirmed that the ESAE_KFCM model constantly outperforms conventional RS algorithms on a variety of assessment measures. 展开更多
关键词 Recommender systems multicriteria rating collaborative filtering sparsity issue scalability issue stacked-autoencoder Kernel Fuzzy C-Means Clustering
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Special Issue:Questions&Data for Better Science and Innovation Call for submissions
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《Journal of Data and Information Science》 CSCD 2024年第3期I0002-I0002,共1页
Editors Yang Wang,Xi'an Jiaotong University Dongbo Shi,Shanghai Jiaotong University Ye Sun,University College London Zhesi Shen,National Science Library,CAS Topic of the Special Issue What are the top questions to... Editors Yang Wang,Xi'an Jiaotong University Dongbo Shi,Shanghai Jiaotong University Ye Sun,University College London Zhesi Shen,National Science Library,CAS Topic of the Special Issue What are the top questions towards better science and innovation and the required data to answer these questions? 展开更多
关键词 COLLEGE QUESTIONS issuE
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Leveraging User-Generated Comments and Fused BiLSTM Models to Detect and Predict Issues with Mobile Apps
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作者 Wael M.S.Yafooz Abdullah Alsaeedi 《Computers, Materials & Continua》 SCIE EI 2024年第4期735-759,共25页
In the last decade, technical advancements and faster Internet speeds have also led to an increasing number ofmobile devices and users. Thus, all contributors to society, whether young or old members, can use these mo... In the last decade, technical advancements and faster Internet speeds have also led to an increasing number ofmobile devices and users. Thus, all contributors to society, whether young or old members, can use these mobileapps. The use of these apps eases our daily lives, and all customers who need any type of service can accessit easily, comfortably, and efficiently through mobile apps. Particularly, Saudi Arabia greatly depends on digitalservices to assist people and visitors. Such mobile devices are used in organizing daily work schedules and services,particularly during two large occasions, Umrah and Hajj. However, pilgrims encounter mobile app issues such asslowness, conflict, unreliability, or user-unfriendliness. Pilgrims comment on these issues on mobile app platformsthrough reviews of their experiences with these digital services. Scholars have made several attempts to solve suchmobile issues by reporting bugs or non-functional requirements by utilizing user comments.However, solving suchissues is a great challenge, and the issues still exist. Therefore, this study aims to propose a hybrid deep learningmodel to classify and predict mobile app software issues encountered by millions of pilgrims during the Hajj andUmrah periods from the user perspective. Firstly, a dataset was constructed using user-generated comments fromrelevant mobile apps using natural language processing methods, including information extraction, the annotationprocess, and pre-processing steps, considering a multi-class classification problem. Then, several experimentswere conducted using common machine learning classifiers, Artificial Neural Networks (ANN), Long Short-TermMemory (LSTM), and Convolutional Neural Network Long Short-Term Memory (CNN-LSTM) architectures, toexamine the performance of the proposed model. Results show 96% in F1-score and accuracy, and the proposedmodel outperformed the mentioned models. 展开更多
关键词 Mobile apps issues play store user comments deep learning LSTM bidirectional LSTM
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Mindfulness and mindful parenting:Strategies for preschoolers with behavioral issues
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作者 Yan Zeng Jun-Wen Zhang Jian Yang 《World Journal of Clinical Cases》 SCIE 2024年第31期6447-6450,共4页
The behavior issues of preschoolers are closely related to their parents'parenting styles.This editorial discusses the value and strategies for solving behavior issues in preschoolers from the perspectives of mind... The behavior issues of preschoolers are closely related to their parents'parenting styles.This editorial discusses the value and strategies for solving behavior issues in preschoolers from the perspectives of mindfulness and mindful parenting.We expect that upcoming studies will place greater emphasis on the behavioral concerns of preschoolers and the parenting practices that shape them,particularly focusing on proactive interventions for preschoolers'behavioral issues. 展开更多
关键词 MINDFULNESS Mindful parenting PRESCHOOLERS Behavioral issues Parenting strategies
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Identifying influencing factors and characterizing key issues in urban sustainable development capacity through machine learning
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作者 Houbo Zhou Lijie Gao +1 位作者 Longyu Shi Qiuli Lv 《Chinese Journal of Population,Resources and Environment》 2024年第3期291-304,共14页
In response to the United Nations Sustainable Development Goals and China’s“Dual Carbon”Goals(DCGs means the goals of“Carbon Peak and carbon neutrality”),this paper from the perspective of the construction of Ch... In response to the United Nations Sustainable Development Goals and China’s“Dual Carbon”Goals(DCGs means the goals of“Carbon Peak and carbon neutrality”),this paper from the perspective of the construction of China’s Innovation Demonstration Zones for Sustainable Development Agenda(IDZSDAs),combines carbon emission-related metrics to construct a comprehensive assessment system for Urban Sustainable Development Capacity(USDC).After obtaining USDC assessment results through the assessment system,an approach combining Least Absolute Shrinkage and Selection Operator(LASSO)regression and Random Forest(RF)based on machine learning is proposed for identifying influencing factors and characterizing key issues.Combining Coupling Coordination Degree(CCD)analysis,the study further summarizes the systemic patterns and future directions of urban sustainable development.A case study on the IDZSDAs from 2015 to 2022 reveals that:(1)the combined identification method based on machine learning and CCD models effectively quantifies influencing factors and key issues in the urban sustainable development process;(2)the correspondence between influencing factors and key subsystems identified by the LASSO-RF combination model is generally consistent with the development situations in various cities;and(3)the machine learning-based combined recognition method is scalable and dynamic.It enables decision-makers to accurately identify influencing factors and characterize key issues based on actual urban development needs. 展开更多
关键词 Urban sustainable development capacity SDGs Dual Carbon Goals Factor identification issue characterization Machine learning
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Performance Evaluation of Low-Cost Dual-Frequency GNSS Receivers for Precise Positioning in Senegal: Issues and Challenges
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作者 Diogoye Diouf Oustasse Abdoulaye Sall +1 位作者 Ibrahima Khalil Gueye Fatou Ndiaye 《Journal of Analytical Sciences, Methods and Instrumentation》 2024年第2期23-37,共15页
The development of this technology has favored the advances noted in recent years in the field of precise positioning. It has also paved the way for a wide range of research into the evaluation of their performance an... The development of this technology has favored the advances noted in recent years in the field of precise positioning. It has also paved the way for a wide range of research into the evaluation of their performance and reliability, their potential use in different fields, the improvement of performance and combined systems, etc. Single-frequency GNSS receivers, which for a long time remained the only category of low-cost GNSS receivers, often limited by their level of accuracy (metric) mainly due to their single-frequency nature, have been joined in the last decade by dual-frequency GNSS receivers developed by certain manufacturers of positioning equipment. These receivers now offer possible alternatives to the relatively expensive conventional (topographic quality) or geodetic receivers and. In this study, the performance of these low-cost dual-frequency receivers was evaluated in static and real-time kinematic GNSS positioning modes. Static positioning was carried out on three points with sessions of 2 h and 4 h over three days with antenna swapping (CHC i50, Leica GS14 and Emlid Reach RS2+). Real-time observations were carried out on eleven (11) points in open, poorly open and not at all open environments, in order to assess not only performance but also receiver sensitivity in environments with a high risk of multipath. The results obtained showed an average agreement of 2 cm in planimetry between the low-cost Emlid RS2+ receiver and the Leica GS14 and CHC i50 receivers. The differences in altimetry are nevertheless greater (sometimes up to decimetres for certain points). Real-time positioning results provided an average convergence of around 1 cm on the E, N and H components with the results from the low-cost Emlid Reach RS2+ and Ublox ZED-F9P receivers and the CHC i50 receiver. Analysis of the results obtained has enabled us to highlight the various issues and challenges associated with this new generation of GNSS receivers, with a view to enhancing their appropriation and optimal integration in the professional and research worlds. 展开更多
关键词 Low-Cost GNSS NRTK Precise Positioning issuES CHALLENGES
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Comparative Study on the Policy of Multiplicity Issues in Clinical Trials at Home and Abroad
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作者 Gong Jingran Chang Yingnan +1 位作者 Qiao Jiahui Chen Yuwen 《Asian Journal of Social Pharmacy》 2024年第1期43-49,共7页
Objective To study the content of China’s guiding principles on multiplicity issues in clinical trials,and to provide reference for the revision of China’s relevant guiding principles.Methods Based on ICH E9,the sim... Objective To study the content of China’s guiding principles on multiplicity issues in clinical trials,and to provide reference for the revision of China’s relevant guiding principles.Methods Based on ICH E9,the similarities and differences of the guiding principles of US Food and Drug Administration(FDA),European Medicines Agency(EMA),and National Medical Products Administration(NMPA)on the multiplicity issues in clinical trials were compared one by one.Results and Conclusion In general,NMPA guidelines are based on ICH E9,but in detail,the guidelines of FDA and EMA focus differently on the multiplicity issues.Therefore,NMPA guidelines need to be detailed and comprehensive.NMPA guidelines can be refined by referring to foreign guidelines to improve the practical guiding significance for clinical research and promote the level of domestic clinical trials in line with international standards. 展开更多
关键词 clinical trial multiplicity issue solution strategy
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Anode Interfacial Issues in Solid-State Li Batteries:Mechanistic Understanding and Mitigating Strategies 被引量:2
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作者 Jiacheng Wang Liquan Chen +1 位作者 Hong Li Fan Wu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第4期384-404,共21页
All-solid-state Li metal batteries(ASSLBs)using inorganic solid electrolyte(SE)are considered promising alternatives to conventional Li-ion batteries,offering improved safety and boosted energy density.While significa... All-solid-state Li metal batteries(ASSLBs)using inorganic solid electrolyte(SE)are considered promising alternatives to conventional Li-ion batteries,offering improved safety and boosted energy density.While significant progress has been made on improving the ionic conductivity of SEs,the degradation and instability of Li metal/inorganic SE interfaces have become the critical challenges that limit the coulombic efficiency,power performance,and cycling stability of ASSLBs.Understanding the mechanisms of complex/dynamic interfacial phenomena is of great importance in addressing these issues.Herein,recent studies on identifying,understanding,and solving interfacial issues on anode side in ASSLBs are comprehensively reviewed.Typical issues at Li metal/SE interface include Li dendrite growth/propagation,SE cracking,physical contact loss,and electrochemical reactions,which lead to high interfacial resistance and cell failure.The causes of these issues relating to the chemical,physical,and mechanical properties of Li metal and SEs are systematically discussed.Furthermore,effective mitigating strategies are summarized and their effects on suppressing interfacial reactions,improving interfacial Li-ion transport,maintaining interfacial contact,and stabilizing Li plating/stripping are highlighted.The in-depth mechanistic understanding of interfacial issues and complete investigations on current solutions provide foundations and guidance for future research and development to realize practical application of high-performance ASSLB. 展开更多
关键词 all-solid-state Li metal batteries anode interfacial issues interface protection and modification interfacial reaction and evolution li dendrite growth
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Preface to the Special Issue on the 2019—2023 China National Report on Geodesy 被引量:1
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作者 Yamin Dang 《Journal of Geodesy and Geoinformation Science》 CSCD 2023年第3期F0002-F0002,I0001,共2页
This Special Issue presents the progress of research and development on geodesy in China during the time period from January 2019 to June 2023.It was submitted,on behalf of the Chinese National Committee for Internati... This Special Issue presents the progress of research and development on geodesy in China during the time period from January 2019 to June 2023.It was submitted,on behalf of the Chinese National Committee for International Association of Geodesy(CNC-IAG),to the IAG General Assembly at the 28th IUGG General Assembly held in Berlin,Germany,July 11—20,2023.It is hoped that this national report would be of help for Chinese scientists in exchanging the results and ideas in the research,development and application of geodesy with scientists all over the world. 展开更多
关键词 behalf issuE GEODE
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Call for Papers:Special Issue of China Finance Review International Artificial Intelligence and Finance:Modern Approaches and Implications
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《系统管理学报》 CSSCI CSCD 北大核心 2023年第5期1117-1118,共2页
Special Issue Guest Editors·Michael Gofman,Senior Lecturer in Finance at the Hebrew University of Jerusalem·Zhao Jin,Assistant Professor of Finance,CKGSB Special Issue Information Artificial intelligence(AI)... Special Issue Guest Editors·Michael Gofman,Senior Lecturer in Finance at the Hebrew University of Jerusalem·Zhao Jin,Assistant Professor of Finance,CKGSB Special Issue Information Artificial intelligence(AI)is becoming an increasingly important tool for fund managers,CFOs,regulators,traders,investors,and entrepreneurs.The generative AI revolution that started with the ChatGPT. 展开更多
关键词 BECOMING GENERATIVE issuE
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Call for Papers:Special Issue of China Finance Review International Artificial Intelligence and Finance:Modern Approaches and Implications
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《系统管理学报》 CSSCI CSCD 北大核心 2023年第6期1349-1350,共2页
Special Issue Guest Editors·Michael Gofman,Senior Lecturer in Finance at the Hebrew University of Jerusalem·Zhao Jin,Assistant Professor of Finance,CKGSB Special Issue Information Artificial intelligence (AI... Special Issue Guest Editors·Michael Gofman,Senior Lecturer in Finance at the Hebrew University of Jerusalem·Zhao Jin,Assistant Professor of Finance,CKGSB Special Issue Information Artificial intelligence (AI) is becoming an increasingly important tool for fund managers,CFOs,regulators,traders,investors,and entrepreneurs.The generative AI revolution that started with the ChatGPT,has spurred a gale of creative destruction that poses risks and opportunities to most firms in theworld.This general-purpose technology changes the tools that professional and retail investors use to collect,analyze,and process structured and unstructured data. 展开更多
关键词 BECOMING GENERATIVE issuE
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Meaning in Life and Mental Health Issues in Older Adults:A Meta-Analysis
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作者 Shu Nie Jiyoon Lim +2 位作者 Xintian Xu Lei Zheng Yiqun Gan 《International Journal of Mental Health Promotion》 2023年第9期971-984,共14页
This study aims to be the first to use meta-analysis to explore the relationship between meaning in life(MIL)and mental health issues among older adults.A meta-analysis was conducted using six databases,resulting in 1... This study aims to be the first to use meta-analysis to explore the relationship between meaning in life(MIL)and mental health issues among older adults.A meta-analysis was conducted using six databases,resulting in 16 studies with 5,074 participants in total.The“metacor”and“forestplot”packages in R-Studio were used for data analysis.The total effect was calculated using a random-effects model,with I2=86%in the heterogeneity test.The results showed a moderate negative correlation between MIL and mental health issues among older adults,with an average effect of−0.37.Five potential moderating variables were examined:the conceptualization of MIL(value vs.purpose),region(Asian vs.Western countries),residence status(community vs.nursing home vs.hospital),types of mental health issues,and evaluation methods(clinical vs.non-clinical).The first four had no significant moderating effect.The mean correlation coefficients between mental health issues and value/purpose were−0.49/−0.33;the mean correlation coefficients in Asian countries and Western countries were−0.48 and−0.34;the mean correlation coefficients among participants living in community/nursing home/mixed status were−0.33/−0.40/−0.40;the mean correlation coefficients between MIL and depression/others were−0.37/−0.35;however,the negative relationship between MIL and mental health issues was stronger when non-clinical evaluations(self-report only)were used.Specifically,the mean correlation coefficient for non-clinical evaluations was−0.42 and for clinical evaluations was−0.29.This study is the first meta-analysis to identify the negative correlation between older adults’MIL and mental health issues.Significant moderating effects of evaluation methods were found. 展开更多
关键词 Meaning in life mental health issues DEPRESSION ANXIETY META-ANALYSIS older adults
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Psychological Issues among Women Undergoing Fertility Treatment in a Specialist Fertility Hospital, South East Nigeria
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作者 Johnson Akuma Obuna Monday Nwite Igwe 《Open Journal of Obstetrics and Gynecology》 CAS 2023年第4期681-692,共12页
Introduction: In Nigeria, a major reason for marriage is procreation and married couples look forward to having children within a year or two of marriage. The inability to achieve conception and subsequently have a ch... Introduction: In Nigeria, a major reason for marriage is procreation and married couples look forward to having children within a year or two of marriage. The inability to achieve conception and subsequently have a child among couples may lead to psychological complications. Objective: This study assessed the psychological impact of infertility and its management on women receiving treatment at a Fertility Specialist Hospital in a poor resource setting. Methods: This was a cross-sectional study of 376 consenting married women who sought and received fertility treatment at a private Fertility Specialist Hospital, located at Abakaliki, South-East Nigeria between May 1, 2017 and May 31, 2022. Socio-demographic and Structured questionnaires were administered to the participants over a 5-year period. Results: The mean age of the women at presentation was 36.9 (±7.2 SD) years. The majority of the women (227) presented with secondary infertility accounting for 60.4%, while the rest had primary infertility (χ<sup>2</sup> = 16.18, P = 0.001). Male-only factor infertility accounted for 22.9% of all the infertility cases, female-only factor 21.3% while both (male and female factors co-existing) accounted for 52.7% of all the cases. The commonest cause of infertility in the study was poor sperm parameters (176) accounting for 46.8% of cases, tubal factor 19.1% and anovulatory factor 22.3% (χ<sup>2</sup> = 214.21, P = 0.001). Three hundred and thirty four (88.8%) felt depressed, 266 (70.7%) felt guilty about the past, and 222 (59.0%) had suicidal tendencies because of the infertility ordeal. Two hundred and fifty one (66.8%) felt inferior, 237 (63.0%) cried often and 174 (46.3%) were socially withdrawn. However, 10.4% of the women felt satisfied and well. These negative psychological feelings were statistically significant. Concerning the effect on marriage, the closeness of couples was reduced significantly in 57.7%, 62.8% had reduced coital intimacy, 79.3% had frequent quarrel and misunderstanding, 27.9% had threats of divorce while 4.5% had actually divorced and 11.% separated. However, there was no negative effect of infertility in 8.8% of couples. Conclusion: Psychological issues associated with infertility and its management in women include feelings of depression, guilt feelings, suicidal ideation, weeping episodes, social withdrawal, feelings of inferiority, reduced libido, and poverty of intimacy with frequent quarrels and misunderstanding. Women appear to bear more of the psychological issues associated with infertility. Early marriage on the part of the women, preservation of their reproductive youthful ages, and a better understanding of the concept of infertility by the couple will not only reduce the prevalence of infertility but will also reduce the dangerous psychological issues associated with infertility. 展开更多
关键词 INFERTILITY Psychological issues Fertility Treatment Fertility Hospital NIGERIA
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A STUDY ON THE CHRONOLOGY OF COINAGE ISSUED BY TIGRANES Ⅱ
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作者 Roy Arakelian Maxime K.Yevadian 《Journal of Ancient Civilizations》 2023年第1期21-57,125,126,共39页
The question of Tigranes II's coinage and its chronology is one of the main difficulties for Artaxiad numismatics.These coins account for over half of all coin types issued by all the kings of this dynasty over a ... The question of Tigranes II's coinage and its chronology is one of the main difficulties for Artaxiad numismatics.These coins account for over half of all coin types issued by all the kings of this dynasty over a period of almost two centuries(189 BC-AD 16).The abundance and wide range of types,monograms,legends,and tiara shapes have led to differing and sometimes contradictory classifications. 展开更多
关键词 CHRONOLOGY SOMETIMES issued
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Preface to Special Issue on Towards High Performance Ga_(2)O_(3) Electronics: Epitaxial Growth and Power Devices(Ⅰ)
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作者 Genquan Han Shibing Long +2 位作者 Yuhao Zhang Yibo Wang Zhongming Wei 《Journal of Semiconductors》 EI CAS CSCD 2023年第6期4-6,共3页
There is currently great optimism within the electronics community that gallium oxide(Ga_(2)O_(3)) ultra-wide bandgap semiconductors have unprecedented prospects for eventually revolutionizing a rich variety of power ... There is currently great optimism within the electronics community that gallium oxide(Ga_(2)O_(3)) ultra-wide bandgap semiconductors have unprecedented prospects for eventually revolutionizing a rich variety of power electronic applications. Specially, benefiting from its ultra-high bandgap of around 4.8 eV, it is expected that the emerging Ga_(2)O_(3) technology would offer an exciting platform to deliver massively enhanced device performance for power electronics and even completely new applications. 展开更多
关键词 Epitaxial Growth and Power Devices Preface to Special issue on Towards High Performance Ga_(2)O_(3)Electronics POWER
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National Revival and Workers Liberation in the Polish Issue-The Differences Between Marx and Engels and Proudhonists During the First International
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作者 ZHANG Jiong 《Journal of Philosophy Study》 2023年第11期468-476,共9页
In the international communist movement in the 19th century,the national uprising in Europe and the workers’movement were intertwined,forming a complex historical background.The Polish National Uprising in 1863 becam... In the international communist movement in the 19th century,the national uprising in Europe and the workers’movement were intertwined,forming a complex historical background.The Polish National Uprising in 1863 became a historical opportunity for the establishment of the First International.Although the unity of the British workers and the French workers was the realistic basis of the First International,the French workers showed a vague attitude different from the British workers on the Polish issue.In the first Congress of the First International,the French workers who almost are Proudhonists rejected the issue of supporting the Polish nation against the Tsar Russian oppression.Pierre-Joseph Proudhon did not link the Polish issue with the workers’movement,while he insisted that social and economic issues should not be confused with political reconstruction,and artificially separated national revival from workers’liberation.In order to promote and assist the establishment of the First International,Marx made certain consideration and concessions on national issues in the formulation of its declaration and constitution.Then Engels,commissioned by Marx,made some specific interpretations that they based on the difference between nation and nationality,and adhere it to the international national principle,both clearly shows the Marxism view of nation state,reveals the risk if international communist movement limited to the principle of nationalities,and also further reveals the importance to combine two great cause,national revival and workers liberation. 展开更多
关键词 Polish issue national revival worker liberation the First International Proudhonism
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From Quantitative Issues to Structural Ones: An Interpretation of China's Labor Market 被引量:9
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作者 蔡昉 《China Economist》 2016年第1期92-111,共20页
Based on the latest demographic and labor data, this paper reveals the changes in China's labor supply and demonstrates that China's key employment issues are no longer quantitative contradictions but increasingly h... Based on the latest demographic and labor data, this paper reveals the changes in China's labor supply and demonstrates that China's key employment issues are no longer quantitative contradictions but increasingly have become structural issues related to labor market mismatch. Due to real and potential economic growth rates being consistent, cyclical unemployment is, at least for now, not striking. If traditional policy measures continue to be followed in disregard of frictional and structural attributes of the labor market to increase total employment, not only will China's employment issues persist but new labor market problems may arise as well China should focus on addressing structural unemployment contradictions. 展开更多
关键词 cyclical unemployment frictional unemployment structural unemployment quantitative issues of employment structural issues of unemployment
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中国A股“HOT ISSUE”现象的实证检验 被引量:5
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作者 杨胜刚 曾明贤 《证券市场导报》 CSSCI 北大核心 2006年第2期31-35,共5页
本文用2000年1月到2003年12月IPO的294只A股作为样本,来检验“HotIssue”现象在中国市场的存在性和市场气氛假说在中国市场的适应性。检验结果表明,IPO各月收益率与IPO各月发行数量之间不存在显著的正相关关系,但IPO市场持续的高收益使... 本文用2000年1月到2003年12月IPO的294只A股作为样本,来检验“HotIssue”现象在中国市场的存在性和市场气氛假说在中国市场的适应性。检验结果表明,IPO各月收益率与IPO各月发行数量之间不存在显著的正相关关系,但IPO市场持续的高收益使我们并不能否认“HotIssue”市场的存在;市场气氛假说只能部分地解释A股IPO的高收益率。 展开更多
关键词 新股发行抑价 “Hot issue”市场 市场气氛假说
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基于Over-Issued CRL机制证书状态信息分发方法研究
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作者 刘小红 蒋兴浩 +1 位作者 汤劲松 陈抗生 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2002年第2期224-227,共4页
商用 CA或 PKI系统中主要使用定期颁布证书撤消列表 (CRL )来分发证书状态信息 ,但现有方法主要侧重于对 CRL的时间和空间特性改进 ,而对存储库性能的优化 ,尤其是如何有效降低存储库峰值负荷方面仍有一些未解决的问题 .本文通过对现有... 商用 CA或 PKI系统中主要使用定期颁布证书撤消列表 (CRL )来分发证书状态信息 ,但现有方法主要侧重于对 CRL的时间和空间特性改进 ,而对存储库性能的优化 ,尤其是如何有效降低存储库峰值负荷方面仍有一些未解决的问题 .本文通过对现有方法在存储库性能改进不力的分析 ,提出一个新的基于 Over- Issued CRL机制的证书状态信息分发方法 .它通过改变 Over- Issue发放的时间间隔 ,使得 CRL请求率大幅降低并迅速达到稳态 。 展开更多
关键词 证书撤消列表 公钥基础设施 峰值负荷 Over-issued CRL机制 证书状态信息分发 存储库 网络安全 PKI系统
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基于Over-Issued增量CRL发布机制的研究
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作者 刘强 杨伟 王闵 《计算机测量与控制》 CSCD 2006年第1期114-116,共3页
目前关于公钥基础设施(public key infrastructure)中证书撤销问题的主要解决方案是使用X.509证书撤销列表(CRL)来定期发布证书状态信息;现有的发布机制主要针对提高处理时间,而对存储库性能的优化仍然存在一些问题———CRL存储库峰值... 目前关于公钥基础设施(public key infrastructure)中证书撤销问题的主要解决方案是使用X.509证书撤销列表(CRL)来定期发布证书状态信息;现有的发布机制主要针对提高处理时间,而对存储库性能的优化仍然存在一些问题———CRL存储库峰值负荷过大;通过对增量CRL和Over-Issued CRL模型的分析,给出了一种基于Over-Issued增量CRL机制的证书状态信息发布方法;它结合了上述两种模型的优点,通过改变Over-Issued CRL发布的时间间隔和增量CRL发布窗口大小,有效降低了存储库峰值负荷。 展开更多
关键词 证书撤销列表 增量CRL Over-issued CRL峰值负荷
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