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Leveraging User-Generated Comments and Fused BiLSTM Models to Detect and Predict Issues with Mobile Apps 被引量:1
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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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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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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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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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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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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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基于P2P网络的Over-Issued CRL机制研究 被引量:1
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作者 邱钊 陈明锐 《计算机工程与应用》 CSCD 北大核心 2011年第1期80-82,88,共4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(Certifi-cate Revocation List)来定期发布证书状态信息。现有的发布机制存在CRL存储库峰值负荷过重,导致PKI部署成本过高的问... 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(Certifi-cate Revocation List)来定期发布证书状态信息。现有的发布机制存在CRL存储库峰值负荷过重,导致PKI部署成本过高的问题。通过对Over-Issued CRL模型和P2P技术的分析,给出一种基于P2P网络和Over-Issued CRL发布机制,它结合了上述两种技术的优点,有效降低了CRL存储库峰值负荷。 展开更多
关键词 证书撤销列表 公钥基础设施 过量发布证书撤消列表
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Tense and Aspect Issue of Translator Competence
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作者 张俏 《海外英语》 2011年第2X期154-157,共4页
This essay is a research report, which is based on results of grammatical error analysis and interviews with linguistic teachers. These researches are conducted in four language streams, namely, Chinese, Spanish, Kore... This essay is a research report, which is based on results of grammatical error analysis and interviews with linguistic teachers. These researches are conducted in four language streams, namely, Chinese, Spanish, Korean and Japanese. It will talk about problems identified in all these four language streams, with Chinese as the focus. Although according to various definitions, translation competence includes several parts, which are all required for a professional translator; this essay covers mainly the linguistic competence with tense and aspect issue as the main point. Meanwhile, some major causes of mistakes will be identified, such as interference of mother tongue, lack of second language proficiency. In the end, some possible ways for improvement are presented for reaching what are needed for a professional translator. 展开更多
关键词 TENSE TRANSLATOR ASPECT issue
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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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Special Issue on Machine Fault Diagnostics and Prognostics 被引量:5
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作者 Zhigang Tian Wilson Wang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第6期1283-1284,共2页
Machine components and systems, such as gears, bearings, pipes, cutting tools and turbines, may experience various types of faults, such as breakage, crack, pitting, wear, corrosion. If not being properly monitored an... Machine components and systems, such as gears, bearings, pipes, cutting tools and turbines, may experience various types of faults, such as breakage, crack, pitting, wear, corrosion. If not being properly monitored and treated, such faults can propagate and lead to machinery perfor- mance degradation, malfunction, or even severe compo- nent/system failure. It is significant to reliably detect machinery defects, evaluate their severity, predict the fault propagation trends, and schedule optimized maintenance and inspection activities to prevent unexpected failures. Advances in these areas will support ensuring equipment and production reliability, safety, quality and productivity. 展开更多
关键词 Special issue Machine Fault Diagnostics PROGNOSTICS
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The States-of-arts and Key Scientific Issues on Durability Research of Concrete Structures 被引量:3
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作者 金伟良 赵羽习 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第z1期1-8,共8页
Concrete has traditionally been regarded as a durable material requiring little or no maintenance. However, over the past several decades, a number of durability related problems have emerged and stimulated research i... Concrete has traditionally been regarded as a durable material requiring little or no maintenance. However, over the past several decades, a number of durability related problems have emerged and stimulated research into the factors relating to concrete durability globally. The challenge now facing practicing engineers is how to design and build structures that not only satisfy the specified structural requirements, but also achieve the performance levels required from a durability standpoint. Research works on concrete structural durability have been widely reported in the literature over the last several decades. In this paper, reviews of four stages of research work on durability, i e, environments, materials, components, and structures, were presented. Afterwards, the key scientific issues in this field were also pointed out. 展开更多
关键词 concrete structures DURABILITY state of the art key scientific issues
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Environmental Issues Related to Chemical Fertilizer Use in China 被引量:17
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作者 CAO ZHIHONG (LMCP, Institute of Soil Science, Academia Sinica, P. O. Box 821, Nanjing 210008 China) 《Pedosphere》 SCIE CAS CSCD 1996年第4期289-303,共15页
The current status of chemical fertilizers production and consumption in China as well as their important roles in Chinese modern agriculture are discussed with special concerns to the environmental issues related to ... The current status of chemical fertilizers production and consumption in China as well as their important roles in Chinese modern agriculture are discussed with special concerns to the environmental issues related to chemical fertilizer use. On the one hand, the total amount of chemical fertilizer produced is insufficient to meet the agricultural needs. On the other hand, the production and consumption of chemical fertilizers in China are obviously not balanced. In some areas over application of nitrogen fertilizers and loss of phosphate fertilizer due to soil erosion have resulted in some undesirable environmental problems such as increase of nitrate in water and eutrophication of water bodies. Maximum scientific uses of organic manures in combination with reasonable use of chemical fertilizers are part of good practices not only in increasing soil productivity and keeping sustainable agriculture development but also in mimimizing their detrimental effects on the environment. 展开更多
关键词 chemical fertilizer environmental issues modern agriculture
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Coal mining in northeast India: an overview of environmental issues and treatment approaches 被引量:16
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作者 Mayuri Chabukdhara O. P. Singh 《International Journal of Coal Science & Technology》 EI 2016年第2期87-96,共10页
Northeast India has a good deposit of sub-bituminous tertiary coal. The northeast Indian coals have unusual physico-chemical characteristics such as high sulfur, volatile matter and vitrinite content, and low ash cont... Northeast India has a good deposit of sub-bituminous tertiary coal. The northeast Indian coals have unusual physico-chemical characteristics such as high sulfur, volatile matter and vitrinite content, and low ash content. In addition, many environmental sensitive organic and mineral bound elements such as Fe, Mg, Bi, AI, V, Cu, Cd, Ni, Pb, and Mn etc. remain enriched in these coals. Such characteristics are associated with more severe environmental impacts due to mining and its utilization in coal based industries. Environmental challenges include large scale landscape damage, soil erosion, loss of forest ecosystem and wildlife habitat, air, water and soil pollution. Several physical and chemical methods are reported in literature for the removal of mineral matter, total sulfur and different forms of sulfur from high sulfur coal in northeast India. This paper may help different researchers and stakeholders to understand current state of research in the field. Initiatives may be taken towards sustainable use of coal resources by adopting innovative clean technologies and by implementing effective control measures and regulatory policies. 展开更多
关键词 Northeast India Sub-bituminous coal Environmental issues Innovative technologies Management andregulatory policies
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Preface to the Special Issue on the “Observation,Prediction and Analysis of severe Convection of China”(OPACC) National “973” Project 被引量:8
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作者 Ming XUE 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第10期1099-1101,共3页
China is a country that is frequently affected by severe convective weather. Here, severe convective weather mainly refers to intense local heavy precipitation, thunderstorm-induced gale-force winds including those fr... China is a country that is frequently affected by severe convective weather. Here, severe convective weather mainly refers to intense local heavy precipitation, thunderstorm-induced gale-force winds including those from tornadoes and downbursts, and hail and lightning. These types of severe weather are usually small in spatial scale and rapid in their development, and are therefore difficult to capture by observational networks and are poorly resolved in typical operational numerical weather prediction (NWP) models. Furthermore, many of the important dynamic and physical processes involved are not well understood. Within China, the impacts of severe convective weather rank only after those of landfalling typhoons and widespread heavy precipitation and flooding. Studies (e.g., Zhang and Zhai, 2011) have shown tendencies for an increased frequency in short-duration extreme precipitation during the past several decades over most of eastern China, where the population is most dense. An in-depth understanding of severe convective weather in China, as well as being able to accurately predict it, is clearly of great importance. 展开更多
关键词 PROJECT NATIONAL Preface to the Special issue on the
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Consideration of some key issues of carbon market development in China 被引量:2
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作者 Sizhen Peng Ying Chang Jiutian Zhang 《Chinese Journal of Population,Resources and Environment》 2015年第1期10-15,共6页
The global carbon market has developed rapidly with two significant trends of globalization and financialization.Deriving economic interest is a nation driven-force behind the international climate negotiation and car... The global carbon market has developed rapidly with two significant trends of globalization and financialization.Deriving economic interest is a nation driven-force behind the international climate negotiation and carbon market.According to deeply analyzed relationships between the carbon market and the key subjects of the climate negotiation,this article reveals that promoting the development of the global carbon market is one of the core interests of developed nations.Based on the background of international carbon market development and domestic carbon market pilots,four suggestions to the key issues of China's carbon market are provided.The first is that the goal of China's carbon market should be in line with and contribute to the national objectives and policies addressing climate change.The second is that the Chinese carbon market should mainly target the emission reduction of production-sectors,and contribute to their upgradation and transformation.The third is mat the development of the nation-wide carbon market in China should first take the principle of unbalanced regional development into consideration.The fourth is that linking China's carbon market to the international market should keep steps in line with international opening-up of China's financing system. 展开更多
关键词 CLIMATE NEGOTIATIONS international CARBON MARKET China’s CARBON MARKET key issues
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Introduction to Urban and Community Forestry in the United States of America: History, Accomplishments, Issues and Trends 被引量:3
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作者 Qi Yadong Zhang Zhiqiang 《Forestry Studies in China》 CAS 2003年第4期54-61,共8页
The urban and community forestry movement in the United States has matured over the last 20 years from managing street trees, to understanding the benefits of trees in urban ecosystems, and now to managing urban green... The urban and community forestry movement in the United States has matured over the last 20 years from managing street trees, to understanding the benefits of trees in urban ecosystems, and now to managing urban green infrastructure. This paper introduced the history, development, and major accomplishments of the urban and community forestry movement, highlighted the economic, ecological, environmental, and social values of forests and trees to communities, and discussed issues and trends of the urban and community forestry program in the United States. 展开更多
关键词 urban and community forestry urban forest benefits and values HISTORY accomplishments issueS trends United States
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