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OCLC启动WorldCat Local快速启动计划
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《图书情报工作动态》 2009年第5期28-29,共2页
OCLC正在将世界各地成员馆的信息资源、技术和专家技能结合起来,共同创建全球首个网络规模(Web—scale)的图书馆协作管理服务,即World CatLocal。目前,OCLC推出World CatLocal快速启动计划,从而OCLC成员馆可以率先参与这一协作服... OCLC正在将世界各地成员馆的信息资源、技术和专家技能结合起来,共同创建全球首个网络规模(Web—scale)的图书馆协作管理服务,即World CatLocal。目前,OCLC推出World CatLocal快速启动计划,从而OCLC成员馆可以率先参与这一协作服务模型。 展开更多
关键词 OCLC World 协作管理 服务模型 信息资源 网络规模 成员馆 图书馆
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OCLC发布软件包帮助博物馆交换数据
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《图书情报工作动态》 2009年第5期29-30,共2页
OCLC研究部门日前发布一种软件包,旨在帮助博物馆之间交换对象描述信息并共享数据。美国梅隆基金会(The Andrew W.Mellon Foundation)为基础设施建设项目提供资金,使博物馆数据的交换成为可能。
关键词 OCLC 博物馆 软件包 基础设施建设项目 基金会 信息
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OCLC与HathiTrust合作——提高数字资源的能见度
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《图书情报工作动态》 2009年第3期26-26,F0003,共2页
OCLC将与HathiTrust(美国二十多家大型研究型图书馆组成的联盟,致力于合作开发海量数字资源存储库)开展合作,目的是提高HathiTrust共享数字化存储库中资源的能见度和访问率。
关键词 数字资源存储 合作开发 OCLC 能见度 研究型图书馆 数字化存储
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The R-and AR-indices:Complementing the h-index 被引量:119
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作者 JIN BiHui LIANG LiMing +1 位作者 Ronald ROUSSEAU Leo EGGHE 《Chinese Science Bulletin》 SCIE EI CAS 2007年第6期855-863,共9页
Based on the foundation laid by the h-index we introduce and study the R- and AR-indices. These new indices eliminate some of the disadvantages of the h-index, especially when they are used in combina-tion with the h-... Based on the foundation laid by the h-index we introduce and study the R- and AR-indices. These new indices eliminate some of the disadvantages of the h-index, especially when they are used in combina-tion with the h-index. The R-index measures the h-core’s citation intensity, while AR goes one step further and takes the age of publications into account. This allows for an index that can actually in-crease and decrease over time. We propose the pair (h, AR) as a meaningful indicator for research evaluation. We further prove a relation characterizing the h-index in the power law model. 展开更多
关键词 R指数 AR指数 H指数 G指数 出版物 引文分析
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Overview of advancement and development trend on magnesium alloy 被引量:81
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作者 Tiancai Xu Yan Yang +2 位作者 Xiaodong Peng Jiangfeng Song Fusheng Pan 《Journal of Magnesium and Alloys》 SCIE 2019年第3期536-544,共9页
Magnesium alloys are characterized by their low density(approximately 1.8g/cm3 for magnesium alloys),high strength,large modulus of elasticity,good heat dissipation,good shock absorption,greater ability to withstand i... Magnesium alloys are characterized by their low density(approximately 1.8g/cm3 for magnesium alloys),high strength,large modulus of elasticity,good heat dissipation,good shock absorption,greater ability to withstand impact load than aluminum alloys,good corrosion resistance to organic matter and alkalinity.According to the statistical analysis of literature data collected by Web of Science Core Collection,it can be found that the growth rate of publications on magnesium alloy during 2008-2018 is significantly higher than the overall growth rate of alloy research papers.In the past 11 years,the Web of Science Core Collection has collected 21,440 papers on magnesium alloys,averaging nearly 2000 papers annually,of which 2768 papers were collected in 2018,an increase of 206%over 2008,accounting for more than one fifth o f the total literature on alloy research.Magnesium alloys have become an important lightweight metallic structural material and have been widely studied worldwide.As the only journal focusing on magnesium alloy research which devoted to the coverage and dissemination of global research on magnesium alloys.This article statistically analyzes all the academic articles published by Journal of Magnesium and Alloys(JMA)from 2013 to 2018 and compares them with all the articles containing magnesium alloy in their titles on the Web of Science during this period.The development trends of magnesium alloys are summarized based on these articles,and the influence and academic value of the articles published by JMA are summarized as well.This paper hopes to better realize the value of JMA,help better spread the academic research of magnesium alloys,and promote the development of global magnesium alloy research.©2019 Published by Elsevier B.V.on behalf of Chongqing University. 展开更多
关键词 Magnesium alloy Developing trend Research hotspots IMPACT
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Ulinastatin for acute lung injury and acute respiratory distress syndrome: A systematic review and meta-analysis 被引量:63
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作者 Yu-Xin Leng Shu-Guang Yang +2 位作者 Ya-Han Song Xi Zhu Gai-Qi Yao 《World Journal of Critical Care Medicine》 2014年第1期34-41,共8页
AIM: To investigate the efficacy and safety of ulinastatin for patients with acute lung injury(ALI) and those with acute respiratory distress syndrome(ARDS).METHODS: A systematic review of randomized controlled trials... AIM: To investigate the efficacy and safety of ulinastatin for patients with acute lung injury(ALI) and those with acute respiratory distress syndrome(ARDS).METHODS: A systematic review of randomized controlled trials(RCTs) of ulinastatin for ALI/ARDS was conducted. Oxygenation index, mortality rate [intensive care unit(ICU) mortality rate, 28-d mortality rate] and length of ICU stay were compared between ulinastatin group and conventional therapy group. Meta-analysis was performed by using Rev Man 5.1.RESULTS: Twenty-nine RCTs with 1726 participants were totally included, the basic conditions of which were similar. No studies discussed adverse effect. Oxygenation index was reported in twenty-six studies(1552 patients). Ulinastatin had a significant effect in improving oxygenation [standard mean difference(SMD) = 1.85, 95%CI: 1.42-2.29, P < 0.00001, I2 = 92%]. ICUmortality and 28-d mortality were respectively reported in eighteen studies(987 patients) and three studies(196 patients). We found that ulinastatin significantly decreased the ICU mortality [I2 = 0%, RR = 0.48, 95%CI: 0.38-0.59, number needed to treat(NNT) = 5.06, P < 0.00001], while the 28-d mortality was not significantly affected(I2 = 0%, RR = 0.78, 95%CI: 0.51-1.19, NNT = 12.66, P = 0.24). The length of ICU stay(six studies, 364 patients) in the ulinastatin group was significantly lower than that in the control group(SMD =-0.97, 95%CI:-1.20--0.75, P < 0.00001, I2 = 86%). CONCLUSION: Ulinastatin seems to be effective for ALI and ARDS though most trials included were of poor quality and no information on safety was provided. 展开更多
关键词 ULINASTATIN ACUTE lung injury ACUTE RESPIRATORY DISTRESS syndrome Mortality OXYGENATION index
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A quantitative comparison and analysis on the assessment indicators of greenhouse gases emission 被引量:47
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作者 ZHANG Zhiqiang QU Jiansheng ZENG Jingjing 《Journal of Geographical Sciences》 SCIE CSCD 2008年第4期387-399,共13页
Anthropogenic greenhouse gases (GHG) emission and related global warming issues have been the focus of international communities for some time. The international communities have reached a consensus to reduce anthro... Anthropogenic greenhouse gases (GHG) emission and related global warming issues have been the focus of international communities for some time. The international communities have reached a consensus to reduce anthropogenic GHG emissions and restrain global warming. The quantitative assessment of anthropogenic GHG emissions is the scientific basis to find out the status of global GHG emission, identify the commitments of each country, and arrange the international efforts of GHG emission reduction. Currently the main assessment indicators for GHG emission include national indicator, per capita indicator, per GDP indicator, and international trade indicator etc. The introduction to the above indi- cators is put forward and their merits and demerits are analyzed. Based on the GHG emission data from the World Resource Institute (WRI), the US Energy Information Administration (EIA), and the Carbon Dioxide Information Analysis Center (CDIAC), the results of each indictor are calculated for the world, for the eight G8 industrialized countries (USA, UK, Canada, Japan, Germany, France, Italy and Russia), and the five major developing countries including China, Brazil, India, South Africa and Mexico. The paper points out that all these indicators have some limitations. The Indicator of Industrialized Accumulative Emission per Capita (IAEC) is put forward as the equitable indicator to evaluate the industrialized historical accumulative emission per capita of every country. IAEC indicator can reflect the economic achievement of GHG emission enjoyed by the current generations in every country and their commitments. The analysis of IAEC indicates that the historical accumulative emission per capita in indus- trialized countries such as UK and USA were typically higher than those of the world average and the developing countries. Emission indicator per capita per GDP, consumptive emission indicator and survival emission indicator are also put forward and discussed in the paper. 展开更多
关键词 global warming greenhouse gases (GHG) emission assessment indicator Industrialized Accumulative Emission per Capita (IAEC) emission indicator per capita per GDP
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Effectiveness of exercise in hepatic fat mobilization in nonalcoholic fatty liver disease: Systematic review 被引量:32
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作者 Pegah Golabi Cameron T Locklear +4 位作者 Patrick Austin Sophie Afdhal Melinda Byrns Lynn Gerber Zobair M Younossi 《World Journal of Gastroenterology》 SCIE CAS 2016年第27期6318-6327,共10页
AIM: To investigate the efficacy of exercise interventions on hepatic fat mobilization in non-alcoholic fatty liver disease(NAFLD) patients.METHODS: Ovid-Medline, Pub Med, EMBASE and Cochrane database were searched fo... AIM: To investigate the efficacy of exercise interventions on hepatic fat mobilization in non-alcoholic fatty liver disease(NAFLD) patients.METHODS: Ovid-Medline, Pub Med, EMBASE and Cochrane database were searched for randomized trials and prospective cohort studies in adults aged ≥ 18 which investigated the effects of at least 8 wk of exercise only or combination with diet on NAFLD from 2010 to 2016. The search terms used to identify articles, in which exercise was clearly described by type, duration, intensity and frequency were: "NASH", "NAFLD", "nonalcoholic steatohepatitis", "non-alcoholic fatty liver disease", "fat", "steatosis", "diet", "exercise", "MR spectroscopy" and "liver biopsy". NAFLD diagnosis, as well as the outcome measures, was confirmed by either hydrogen-magnetic resonance spectroscopy(H-MRS) or biopsy. Trials that included dietary interventions along with exercise were accepted if they met all criteria. RESULTS: Eight studies met selection criteria(6 with exercise only, 2 with diet and exercise with a total of 433 adult participants). Training interventions ranged between 8 and 48 wk in duration with a prescribed exercise frequency of 3 to 7 d per week, at intensities between 45% and 75% of VO2 peak. The most commonly used imaging modality was H-MRS and one study utilized biopsy. The effect of intervention on fat mobilization was 30.2% in the exercise only group and 49.8% in diet and exercise group. There was no difference between aerobic and resistance exercise intervention, although only one study compared thetwo interventions. The beneficial effects of exercise on intrahepatic triglyceride(IHTG) were seen even in the absence of significant weight loss. Although combining an exercise program with dietary interventions augmented the reduction in IHTG, as well as improved measures of glucose control and/or insulin sensitivity, exercise only significantly decreased hepatic lipid contents.CONCLUSION: Prescribed exercise in subjects with NAFLD reduces IHTG independent of dietary intervention. 展开更多
关键词 Non-alcoholic FATTY liver disease EXERCISE Diet FAT MOBILIZATION LIFESTYLE modification
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Comparison of the effect and safety of Kuntai capsule and hormone replacement therapy in patients with perimenopausal syndrome:a systematic review and Meta-analysis 被引量:30
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作者 Du Xiaoqin Xu Lin +4 位作者 Wang Lijun Heng Mingli Bu Huaien Hao Yu Tian Jinhui 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2017年第3期279-285,共7页
OBJECTIVE: To assess the effectiveness and safety of Kuntai capsule and hormone replacement therapy in treatment of perimenopausal syndrome.METHODS: Articles were retrieved from the databases Cochrane Database of Syst... OBJECTIVE: To assess the effectiveness and safety of Kuntai capsule and hormone replacement therapy in treatment of perimenopausal syndrome.METHODS: Articles were retrieved from the databases Cochrane Database of Systematic Reviews,Pub Med, Chinese National Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang Database. Only randomized controlled trials were included; 15 trials involving1243 patients were identified from January 2005 to April 2015. A systemic review and Meta-analysis of publications was performed. The review was limit-ed to randomized controlled trials that compared Kuntai capsule and hormone replacement therapy to treat perimenopausal syndrome for at least 3months. The primary outcome assessed was the treatment efficacy at 3 months, including effective rate of Kupperman menopausal scores, Kupperman menopausal scores, and blood estradiol(E2) or blood follicle stimulating hormone(FSH) levels.Other outcomes assessed were safety or adverse events, such as gastrointestinal complaints, breast distending pain, or vaginal bleeding.RESULTS: Kupperman menopausal scores showed no significant difference in effective rate [odds ratio(OR): 1.05, 95% confidence intervals(CI): 0.71 to1.55] and changes in FSH level [mean difference(MD): 2.14, 95% CI:-2.36 to 6.65]. There was a significant statistical difference in Kupperman menopausal scores(MD:-1.14, 95% CI:-2.03 to-0.25)and changes in E2level(MD:-16.41, 95% CI:-18.83to-13.69). There were fewer adverse events in the Kuntai capsule group than in the hormone replacement therapy group(OR: = 0.35, 95% CI: 0.25 to0.48, P < 0.01).CONCLUSION: Compared with hormone replacement therapy, Kuntai capsule can improve perimenopausal symptoms and blood E2 levels, and reduce the incidence of adverse events. 展开更多
关键词 Hormone replacement therapy Peri-menopause POSTMENOPAUSE Drug.related side ef-fects and adverse reactions Randomized con-trolled trial Review
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The state of the science of nurse work environments in the United States: A systematic review 被引量:25
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作者 Holly Wei Kerry A.Sewell +1 位作者 Gina Woody Mary Ann Rose 《International Journal of Nursing Sciences》 2018年第3期287-300,共14页
A healthy nurse work environment is a workplace that is safe,empowering,and satisfying.Many research studies were conducted on nurse work environments in the last decade;however,it lacks an overview of these research ... A healthy nurse work environment is a workplace that is safe,empowering,and satisfying.Many research studies were conducted on nurse work environments in the last decade;however,it lacks an overview of these research studies.The purpose of this review is to identify,evaluate,and summarize the major foci of studies about nurse work environments in the United States published between January 2005 and December 2017 and provide strategies to improve nurse work environments.Databases searched included MEDLINE via PubMed,CINAHL,PsycINFO,Nursing and Allied Health,and the Cochrane Library.The literature search followed the PRISMA guideline.Fifty-four articles were reviewed.Five major themes emerged:1)Impacts of healthy work environments on nurses'outcomes such as psychological health,emotional strains,job satisfaction,and retention;2)Associations between healthy work environments and nurse interpersonal relationships at workplaces,job performance,and productivity;3)Effects of healthy work environments on patient care quality;4)Influences of healthy work environments on hospital accidental safety;and 5)Relationships between nurse leadership and healthy work environments.This review shows that nurses,as frontline patient care providers,are the foundation for patient safety and care quality.Promoting nurse empowerment,engagement,and interpersonal relationships at work is rudimental to achieve a healthy work environment and quality patient care.Healthier work environments lead to more satisfied nurses who will result in better job performance and higher quality of patient care,which will subsequently improve healthcare organizations'financial viability.Fostering a healthy work environment is a continuous effort. 展开更多
关键词 Care quality NURSE Nursing leadership SELF-CARE Work environments
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基于全文内容的学术论文研究方法自动分类研究 被引量:25
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作者 章成志 李卓 储荷婷 《情报学报》 CSSCI CSCD 北大核心 2020年第8期852-862,共11页
对学术论文所采用的研究方法进行自动分类,有助于研究方法使用行为的分析与研究方法的评估,进而为科研人员推荐或选择合适的研究方法提供依据。相比于摘要信息,全文内容包含更多关于研究方法的上下文信息,因此探索基于全文内容的学术论... 对学术论文所采用的研究方法进行自动分类,有助于研究方法使用行为的分析与研究方法的评估,进而为科研人员推荐或选择合适的研究方法提供依据。相比于摘要信息,全文内容包含更多关于研究方法的上下文信息,因此探索基于全文内容的学术论文研究方法自动分类具有重要的意义。本研究以图书情报领域的820篇学术论文全文为研究对象,邀请专家对其研究方法进行标注得到研究方法训练语料;采用多标签分类任务中问题转换法和算法自适应法,将朴素贝叶斯与支持向量机作为问题转换法的底层分类器,构建6种不同的分类模型,同时选用算法自适应法中的ML-KNN模型,分别对论文中使用的研究方法进行自动分类。实验结果表明,相较于学术论文的摘要信息,全文内容在研究方法分类的性能上有较大的提升;朴素贝叶斯算法在问题转换法的分类器链策略中表现最佳,F1值达到0.705;另外结果也表明不同的学术论文研究方法的特征表征能力不同,训练集的规模较少会导致分类的泛化效果差。 展开更多
关键词 研究方法分类 文本分类 全文内容 多标签分类
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Sharing Clinical Trial Data: A Proposal from the International Committee of Medical Journal Editors 被引量:20
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作者 Darren B Taichman Joyce Backus +13 位作者 Christopher Baethge Howard Bauchner Peter W de Leeuw Jeffrey M Drazen John Fletcher Frank Frizelle Irish Groves Abraham Haileamlak Astrid James Christine Laine Larry Peiperl Anja Pinborg Peush Sahni Si-Nan Wu 《Chinese Medical Journal》 SCIE CAS CSCD 2016年第2期127-128,共2页
The International Committee of Medical Journal Editors (ICMJE) believes that there is an ethical obligation to responsibly share data generated by interventional clinical trials because participants have put themsel... The International Committee of Medical Journal Editors (ICMJE) believes that there is an ethical obligation to responsibly share data generated by interventional clinical trials because participants have put themselves at risk. In a growing consensus, many funders around the world - foundations, government agencies, and industry - now mandate data sharing. Here, we outline ICMJE's proposed requirements to help meet this obligation. We encourage feedback on the proposed requirements. Anyone can provide feedback at www. icmje.org by April 18, 2016. 展开更多
关键词 Clinical Trial Data International Committee of Medical Journal Editors Share
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Novel 3-dimensional virtual hepatectomy simulation combined with real-time deformation 被引量:22
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作者 Yukio Oshiro Hiroaki Yano +4 位作者 Jun Mitani Sangtae Kim Jaejeong Kim Kiyoshi Fukunaga Nobuhiro Ohkohchi 《World Journal of Gastroenterology》 SCIE CAS 2015年第34期9982-9992,共11页
AIM:To develop a novel 3-dimensional(3D) virtual hepatectomy simulation software,Liversim,to visualize the real-time deformation of the liver.METHODS:We developed a novel real-time virtual hepatectomy simulation softw... AIM:To develop a novel 3-dimensional(3D) virtual hepatectomy simulation software,Liversim,to visualize the real-time deformation of the liver.METHODS:We developed a novel real-time virtual hepatectomy simulation software program called Liversim. The software provides 4 basic functions:viewing 3D models from arbitrary directions,changing the colors and opacities of the models,deforming the models based on user interaction,and incising the liver parenchyma and intrahepatic vessels based on user operations. From April 2010 through 2013,99 patients underwent virtual hepatectomies that used the conventional software program SYNAPSE VINCENT preoperatively. Between April 2012 and October 2013,11 patients received virtual hepatectomies using the novel software program Liversim; these hepatectomies were performed both preoperatively and at the same that the actual hepatectomy was performed in an operating room. The perioperative outcomes were analyzed between the patients for whom SYNAPSE VINCENT was used and those for whom Liversim wasused. Furthermore,medical students and surgical residents were asked to complete questionnaires regarding the new software.RESULTS:There were no obvious discrepancies(i.e.,the emergence of branches in the portal vein or hepatic vein or the depth and direction of the resection line) between our simulation and the actual surgery during the resection process. The median operating time was 304 min(range,110 to 846) in the VINCENT group and 397 min(range,232 to 497) in the Liversim group(P = 0.30). The median amount of intraoperative bleeding was 510 m L(range,18 to 5120) in the VINCENT group and 470 m L(range,130 to 1600) in the Liversim group(P = 0.44). The median postoperative stay was 12 d(range,6 to 100) in the VINCENT group and 13 d(range,9 to 21) in the Liversim group(P = 0.36). There were no significant differences in the preoperative outcomes between the two groups. Liversim was not found to be clinically inferior to SYNAPSE VINCENT. Both students and surgical residents reported that th 展开更多
关键词 LIVER SURGERY SIMULATION VIRTUAL HEPATECTOMY Real-
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Masked Sentence Model Based on BERT for Move Recognition in Medical Scientific Abstracts 被引量:20
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作者 Gaihong Yu Zhixiong Zhang +1 位作者 Huan Liu Liangping Ding 《Journal of Data and Information Science》 CSCD 2019年第4期42-55,共14页
Purpose:Mo ve recognition in scientific abstracts is an NLP task of classifying sentences of the abstracts into different types of language units.To improve the performance of move recognition in scientific abstracts,... Purpose:Mo ve recognition in scientific abstracts is an NLP task of classifying sentences of the abstracts into different types of language units.To improve the performance of move recognition in scientific abstracts,a novel model of move recognition is proposed that outperforms the BERT-based method.Design/methodology/approach:Prevalent models based on BERT for sentence classification often classify sentences without considering the context of the sentences.In this paper,inspired by the BERT masked language model(MLM),we propose a novel model called the masked sentence model that integrates the content and contextual information of the sentences in move recognition.Experiments are conducted on the benchmark dataset PubMed 20K RCT in three steps.Then,we compare our model with HSLN-RNN,BERT-based and SciBERT using the same dataset.Findings:Compared with the BERT-based and SciBERT models,the F1 score of our model outperforms them by 4.96%and 4.34%,respectively,which shows the feasibility and effectiveness of the novel model and the result of our model comes closest to the state-of-theart results of HSLN-RNN at present.Research limitations:The sequential features of move labels are not considered,which might be one of the reasons why HSLN-RNN has better performance.Our model is restricted to dealing with biomedical English literature because we use a dataset from PubMed,which is a typical biomedical database,to fine-tune our model.Practical implications:The proposed model is better and simpler in identifying move structures in scientific abstracts and is worthy of text classification experiments for capturing contextual features of sentences.Originality/value:T he study proposes a masked sentence model based on BERT that considers the contextual features of the sentences in abstracts in a new way.The performance of this classification model is significantly improved by rebuilding the input layer without changing the structure of neural networks. 展开更多
关键词 Move recognition BERT Masked sentence model Scientific abstracts
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EndNote个人参考文献图书馆简介与基本使用方法 被引量:19
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作者 焦艳平 Su Hanfling +1 位作者 孙彩霞 宋燕菊 《现代图书情报技术》 CSSCI 北大核心 2004年第4期82-84,共3页
介绍了 End Note个人参考文献图书馆的作用、应用环境和创建方法。举例说明了如何将文献输入到 End Note图书馆中的三种方法 :简单的手工输入 ;先保存数据库的检索结果 ,然后再借助于对应的数据库过滤文件进行输入 ;利用不同数据库或 O... 介绍了 End Note个人参考文献图书馆的作用、应用环境和创建方法。举例说明了如何将文献输入到 End Note图书馆中的三种方法 :简单的手工输入 ;先保存数据库的检索结果 ,然后再借助于对应的数据库过滤文件进行输入 ;利用不同数据库或 OPAC系统的联机检索文件来直接检索并输入。介绍了如何对 End Note图书馆进行检索、分类重排和显示的方法 ,以及如何按照常用的引文和参考文献的著录格式 ,将参考文献插入或输出到文本文件中。 展开更多
关键词 ENDNOTE 个人参考文献图书馆 目录管理软件 数据库检索 联机检索 著录格式
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Type Synthesis of Two-Degrees-of-Freedom Rotational Parallel Mechanism with Two Continuous Rotational Axes 被引量:19
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作者 XU Yundou ZHANG Dongsheng +2 位作者 WANG Min YAO Jiantao ZHAO Yongsheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第4期694-702,共9页
The two-rotational-degrees-of-freedom(2R) parallel mechanism(PM) with two continuous rotational axes(CRAs) has a simple kinematic model.It is therefore easy to implement trajectory planning,parameter calibration... The two-rotational-degrees-of-freedom(2R) parallel mechanism(PM) with two continuous rotational axes(CRAs) has a simple kinematic model.It is therefore easy to implement trajectory planning,parameter calibration,and motion control,which allows for a variety of application prospects.However,no systematic analysis on structural constraints of the 2R-PM with two CRAs has been performed,and there are only a few types of 2R-PM with two CRAs.Thus,a theory regarding the type synthesis of the 2R-PM with two CRAs is systematically established.First,combining the theories of reciprocal screw and space geometry,the spatial arrangement relationships of the constraint forces applied to the moving platform by the branches are explored,which give the 2R-PM two CRAs.The different distributions of the constraint forces in each branch are also studied.On the basis of the obtained structural constraints of branches,and considering the geometric relationships of constraint forces in each branch,the appropriate kinematic chains are constructed.Through the reasonable configuration of branch kinematic chains corresponding to every structural constraint,a series of new 2R-PMs with two CRAs are finally obtained. 展开更多
关键词 type synthesis continuous rotational axes two rotational degrees of freedom parallel mechanism constraint force
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Path Planning for Intelligent Robots Based on Deep Q-learning With Experience Replay and Heuristic Knowledge 被引量:18
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作者 Lan Jiang Hongyun Huang Zuohua Ding 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2020年第4期1179-1189,共11页
Path planning and obstacle avoidance are two challenging problems in the study of intelligent robots. In this paper, we develop a new method to alleviate these problems based on deep Q-learning with experience replay ... Path planning and obstacle avoidance are two challenging problems in the study of intelligent robots. In this paper, we develop a new method to alleviate these problems based on deep Q-learning with experience replay and heuristic knowledge. In this method, a neural network has been used to resolve the "curse of dimensionality" issue of the Q-table in reinforcement learning. When a robot is walking in an unknown environment, it collects experience data which is used for training a neural network;such a process is called experience replay.Heuristic knowledge helps the robot avoid blind exploration and provides more effective data for training the neural network. The simulation results show that in comparison with the existing methods, our method can converge to an optimal action strategy with less time and can explore a path in an unknown environment with fewer steps and larger average reward. 展开更多
关键词 Deep Q-learning(DQL) experience replay(ER) heuristic knowledge(HK) path planning
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呈现科研数据知识库:re3data.org注册机制 被引量:15
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作者 Heinz Pampel Paul Vierkant +8 位作者 Frank Scholze Roland Bertelmann Maxi Kindling Jens Klump Hans-Jürgen Goebelbecker Jens Gundlach Peter Schirmbacher Uwe Dierolf 顾立平 《现代图书情报技术》 CSSCI 北大核心 2014年第3期26-34,共9页
科研人员在钻研科研问题与分享科研数据的过程中,需要某种基础设施来确保数据最大程度的获取性、稳定性和可用性。这类基础设施可以统称为科研数据知识库(Research Data Repository,RDR)。自2012年启动的re3data.org项目,主要从事科研... 科研人员在钻研科研问题与分享科研数据的过程中,需要某种基础设施来确保数据最大程度的获取性、稳定性和可用性。这类基础设施可以统称为科研数据知识库(Research Data Repository,RDR)。自2012年启动的re3data.org项目,主要从事科研数据知识库的登记注册,以及为科研人员、科研资助组织、图书馆和出版商等提供有关异构科研数据知识库的全景概述。截至2013年7月,已有400个科研数据知识库向re3data.org登记,其中288个采用re3data.org的信息图标,以协助科研人员遴选合适的知识库,并且存储与重用他们的数据。这篇论文描绘异构RDR的全景,表述机构的、学科的、跨学科的以及项目专业的RDR类型。深入描述re3data.org的特性,以及这套注册系统如何协助科研人员分辨适合存储和搜索科研数据的知识库。 展开更多
关键词 科研数据 科研数据管理 开放获取 机构知识库发展 开放科学 科研数据知识库 信息管理
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Changes of Temperature and Precipitation Extremes in Hengduan Mountains,Qinghai-Tibet Plateau in 1961-2008 被引量:16
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作者 NING Baoying YANG Xiaomei CHANG Li 《Chinese Geographical Science》 SCIE CSCD 2012年第4期422-436,共15页
Variations and trends in extreme climate events are more sensitive to climate change than the mean values, and so have received much attention. In this study, twelve indices of temperature extremes and 11 indices of p... Variations and trends in extreme climate events are more sensitive to climate change than the mean values, and so have received much attention. In this study, twelve indices of temperature extremes and 11 indices of precipita- tion extremes at 32 meteorological stations in Hengduan Mountains were examined for the period 1961-2008. The re- suits reveal statistically significant increases in the temperature of the warmest and coldest nights and in the frequen- cies of extreme warm days and nights. Decreases of the diurnal temperature range and the numbers of frost days and ice days are statistically significant. Regional averages of growing season length also display the trends consistent and significant with warming. At a large proportion of the stations, patterns of temperature extremes are consistent with warming since 1961: warming trends in minimum temperature indices are greater than those relating to maximum temperature. As the center of the Shaluli Mountain, the warming magnitudes decrease from inner to outer. Changes in precipitation extremes is low: trends are difficult to detect against the larger inter-annual and decadal-scale variability of precipitation, and only the wet day precipitation and the regional trend in consecutive dry days are significant at the 0.05 level. It can be concluded that the variation of extreme precipitation events is not obvious in the Hengduan Mountains, however, the regional trends generally decrease from the south to the north. Overall, the spatial distribution of temporal changes of all extreme climate indices in the Hengduan Mountains illustrated here reflects the climatic complexity in mountainous regions. 展开更多
关键词 precipitation temperature climate extremes global warming Hengduan Mountains Qinghai-Tibet Pla-teau
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Characterization and technology of fast reducing roasting for fine iron materials 被引量:15
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作者 罗立群 黄红 余永富 《Journal of Central South University》 SCIE EI CAS 2012年第8期2272-2278,共7页
The features of the techniques of fast reducing roasting (FRR) and conventional magnetic roasting, as well as tremendous demands of iron ores in iron and steel industry of China, were briefly described. The test equ... The features of the techniques of fast reducing roasting (FRR) and conventional magnetic roasting, as well as tremendous demands of iron ores in iron and steel industry of China, were briefly described. The test equipment suitable for FRR of fine-grained materials was introduced. Weakly magnetic materials with grain size of 〈0.30 mm were converted into strongly magnetic materials by FRR for several to dozens of seconds. In a weakly reducing atmosphere and at 740-800 ~C, refractory powder iron material (〈0.30 mm) which is rich in specularite, limonite and Mg-Mn siderite was subjected to FRR for a few seconds to 60 s. Concentrate with iron grade of 55.67%-55.21%, high contents of Mg and Mn in the ore is obtained and the yield of magnetic separation reaches 81.66%-86.57%. The results of X-ray diffraction (XRD) analysis and magnetism detection of the material before and after FRR indicate that weakly magnetic material is mainly converted into strongly magnetic material Fe304 with specific saturation magnetic moment. The efficiency of FRR is consistent with TFe recovery of magnetic separation; meantime, the specific sa^u'ation magnetic moment increases from 33 to 42 times after FRR. Calculations show that speeds of flash magnetic roasting are obtained from several dozen to two or three hundred times, compared with rotary kiln or shaft furnace. This indicates that it is practicable to use the fast reducing roasting technique to improve the comprehensive utilization of iron ore resources. 展开更多
关键词 iron material reducing roasting thermal decomposition X-ray diffraction magnetic property
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