资源管理是网格计算研究领域中的一项重要研究点,目前的研究工作大多致力于解决异构性问题,对于在交付无缝QoS(quality of service)前提下提高资源分配性能方面还缺乏深入的研究.而且,目前对网格QoS的研究集中于将多媒体网络QoS的相关...资源管理是网格计算研究领域中的一项重要研究点,目前的研究工作大多致力于解决异构性问题,对于在交付无缝QoS(quality of service)前提下提高资源分配性能方面还缺乏深入的研究.而且,目前对网格QoS的研究集中于将多媒体网络QoS的相关成果融入网格体系架构中以提供对网格QoS的支持,而缺少对网格QoS的特性进行系统化的研究与归纳.为此,提出了网格QoS的层次结构模型,并对其中承上启下的虚拟组织层QoS参数进行了新的分类和测量;然后,利用SNAP(service negotiation and acquisition protocol)协议对基于网格QoS层次结构模型的网格QoS参数的映射转换过程进行了分析;最后,设计了网格资源管理仿真系统,并运用相关的网格QoS的研究改进了现有的Min-Min算法.仿真实验结果表明,基于QoS的网格资源管理可以在满足用户QoS需求下,有效地提高网格资源的利用率和服务请求的成功率.展开更多
In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/ser...In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/server setting is proposed, which uses pairings on certain elliptic curves. We show that the newly proposed key agreement protocol is practical and of great efficiency, meanwhile, it satisfies every desired security require ments for key agreement protocols.展开更多
Certificateless public key cryptography was introduced to overcome the key escrow limitation of the identity-based cryptography. It combines the advantages of the identity-based cryptography and the traditional PKI. M...Certificateless public key cryptography was introduced to overcome the key escrow limitation of the identity-based cryptography. It combines the advantages of the identity-based cryptography and the traditional PKI. Many certificateless public key encryption and signature schemes have been proposed. However, the key agreement in CL-PKE is seldom discussed. In this paper, we present a new certificateless two party authentication key agreement protocol and prove its security attributes. Compared with the existing protocol, our protocol is more efficient.展开更多
Precipitation-related extremes are among the most impact-relevant consequences of a warmer climate,particularly for China,a region vulnerable to global warming and with a large population.Understanding the impacts and...Precipitation-related extremes are among the most impact-relevant consequences of a warmer climate,particularly for China,a region vulnerable to global warming and with a large population.Understanding the impacts and risks induced by future extreme precipitation changes is critical for mitigation and adaptation planning.Here,extreme precipitation changes under different levels of global warming and their associated impacts on populations in China are investigated using multimodel climate projections from the Coupled Model Intercomparison Project Phase 5 and population projections under Shared Socioeconomic Pathways.Heavy precipitation would intensify with warming across China at a rate of 6.52%(5.22%-8.57%)per degree of global warming.The longest dry spell length would increase(decrease)south(north)of-34°N.The low warming target of the Paris Agreement could substantially reduce the extreme precipitation related impacts compared to higher warming levels.For the area weighted average changes,the intensification in wet extremes could be reduced by 3.22%,9.42%and 16.70%over China,and the lengthening of dry spells could be reduced by 0.72%,4.75%and 5.31%in southeastern China,respectively,if global warming is limited to 1.5℃as compared to 2,3 and 4℃The Southeastern China is the hotspot of enhanced impacts due to the dense population.The impacts on populations induced by extreme precipitation changes are dominated by climate change,while future population redistribution plays a minor role.展开更多
This paper investigates the controllability of multi-agent systems based on agreement protocols. First, for a group of single-integrator agents, the controllability is studied in a unified framework for both networks ...This paper investigates the controllability of multi-agent systems based on agreement protocols. First, for a group of single-integrator agents, the controllability is studied in a unified framework for both networks with leader-following structure and networks with undirected graph. Some new necessary/sufficient conditions for the controllability of networks of single-integrator agents are established. Second, we prove that, under the same topology and same prescribed leaders, a network of high-order dynamic agents is completely controllable if and only if so is a network of single-integrator agents. Third, how the selection of leaders and the coupling weights of graphs affect the controllability is analyzed. Finally, some numerical simulations are presented to demonstrate the effectiveness of the theoretical results.展开更多
目的通过对3种血压测量方法进行比较,为家庭自测血压用于临床和科研积累经验和科学数据。方法利用"代用盐对高血压患者及其家庭成员降压效果随机双盲对照试验研究"中收集的同一研究对象(n=220)不同方法获得血压(门诊血压、家...目的通过对3种血压测量方法进行比较,为家庭自测血压用于临床和科研积累经验和科学数据。方法利用"代用盐对高血压患者及其家庭成员降压效果随机双盲对照试验研究"中收集的同一研究对象(n=220)不同方法获得血压(门诊血压、家庭自测血压和动态血压)测量数据,以动态血压数据作为参照,比较家庭血压及门诊血压与动态血压的一致性。干预前,217人3种血压测量方法数据均合格;干预结束时,189人3种血压测量方法数据均合格;将干预前和干预结束时测量合格的数据合并分析(n=406)。利用Bland-Altman对3种测量方法测得的血压水平进行组内一致性检验,并进行Person相关性分析;利用McNemar卡方检验比较3种方法的个体内一致率。结果门诊血压、动态血压和家庭自测血压3种方法测得的血压水平(收缩压/舒张压)分别为(149.5±16.4)/ (87.2±9.5)、(137.8±17.1)/(83.2±10.3)和(138.0±14.2)/(82.4±9.3)mm Hg。家庭血压与动态血压的相关性优于门诊血压与动态血压的相关性,相关系数(收缩压/舒张压)分别为(0.55/0.62)和(0.36/0.46)。以动态血压为参照,家庭自测血压水平与动态血压(收缩压/舒张压)差异无统计学意义(-0.2/-0.7 mm Hg,P>0.05),而门诊血压水平显著高于动态血压水平(11.7/4.0 mm Hg,P<0.05);家庭自测血压的收缩压个体内差异显著优于门诊血压(≤|5| mm Hg为28.3%vs 1 6.5%,P<0.05;≤|10| mm Hg为49.7%vs 33.5%,P<0.05),舒张压个体差异略高于门诊血压,但差异无统计学意义(P>0.05)。结论与动态血压测量值相比,家庭自测血压比门诊血压更准确。展开更多
AIM:To validate the usefulness of screening endoscopy findings for predictingHelicobacter pylori (H. pylori) infection status. METHODS:H. pylori infection status was determined by histology, serology, and the urea bre...AIM:To validate the usefulness of screening endoscopy findings for predictingHelicobacter pylori (H. pylori) infection status. METHODS:H. pylori infection status was determined by histology, serology, and the urea breast test in 77 consecutive patients who underwent upper endoscopy. Based on the findings, patients were categorized as H. pylori -uninfected, -infected, or -eradicated cases. Using six photos of certain sites in the stomach per case, we determined the presence or absence of the following endoscopic findings:regular arrangement of collecting venules (RAC), linear erythema, hemorrhage, fundic gland polyp (FGP), atrophic change, rugal hyperplasia, edema, spotty erythema, exudate, xanthoma, and mottled patchy erythema (MPE). The diagnostic odds ratio (DOR) and inter-observer agreement (Kappa value) for these 11 endoscopic findings used in the determination of H. pylori infection status were calculated. RESULTS:Of the 77 patients [32 men and 45 women; mean age (SD), 39.7 (13.4) years] assessed, 28 were H. pylori uninfected, 28 were infected, and 21 were eradicated. DOR values were significantly high (< 0.05) for the following H. pylori cases:uninfected cases with RAC (11.5), linear erythema (24.5), hemorrhage (4.1), and FGP (34.5); for infected cases with atrophic change (8.67), rugal hyperplasia (15.8), edema (14.2), spotty erythema (11.5), and exudate (3.52); and for eradicated cases with atrophic change (32.4) and MPE (103.0). Kappa values were excellent for FGP (0.93), good for RAC (0.63), hemorrhage (0.79), atrophic change (0.74), and MPE (0.75), moderate for linear erythema (0.51), rugal hyperplasia (0.49), edema (0.58), spotty erythema (0.47), and exudate (0.46), and poor for xanthoma (0.19). CONCLUSION:The endoscopic findings of RAC, hemorrhage, FGP, atrophic change, and MPE will be useful for predicting H. pylori infection status.展开更多
Pursuant to the Paris Agreement,China committed itself to peak its carbon emissions by around 2030 and to increase the non-fossil share ofprimary energy to 20%at the same time.The government has supported the internat...Pursuant to the Paris Agreement,China committed itself to peak its carbon emissions by around 2030 and to increase the non-fossil share ofprimary energy to 20%at the same time.The government has supported the international agreement by setting and strengthening the domesticpolicy targets for an earlier peak and faster reduction,aiming to contain the average global temperature increase to well below 2℃.We developa Kaya Inequality method to assess the time of peak and pace of reduction of China's energy-related CO2emissions based on the national energypolicy targets for 2030.We find that,despite the minor fluctuations,the current plateau essentially represents the peak emissions and should entera phase of steady decline by around 2025,given current trends in energy consumption and decarbonization.Such developments would beconsistent with the strengthened national policy target to achieve 50%of renewable power generation by 2030.However,the basic policy targetsea 20%share of non-fossil energy and 6 Gtce in total energy consumption by 2030ewould be insufficient to peak carbon emissions by around 2030.The synergy and interplay between domestic policy target setting and international climate commitments shed light on the need to elevatenational climate ambitions under the Paris Agreement and beyond.展开更多
文摘资源管理是网格计算研究领域中的一项重要研究点,目前的研究工作大多致力于解决异构性问题,对于在交付无缝QoS(quality of service)前提下提高资源分配性能方面还缺乏深入的研究.而且,目前对网格QoS的研究集中于将多媒体网络QoS的相关成果融入网格体系架构中以提供对网格QoS的支持,而缺少对网格QoS的特性进行系统化的研究与归纳.为此,提出了网格QoS的层次结构模型,并对其中承上启下的虚拟组织层QoS参数进行了新的分类和测量;然后,利用SNAP(service negotiation and acquisition protocol)协议对基于网格QoS层次结构模型的网格QoS参数的映射转换过程进行了分析;最后,设计了网格资源管理仿真系统,并运用相关的网格QoS的研究改进了现有的Min-Min算法.仿真实验结果表明,基于QoS的网格资源管理可以在满足用户QoS需求下,有效地提高网格资源的利用率和服务请求的成功率.
基金Supported bythe National Natural Science Foundationof China (60225007 ,60572155) the Science and Technology ResearchProject of Shanghai (04DZ07067)
文摘In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/server setting is proposed, which uses pairings on certain elliptic curves. We show that the newly proposed key agreement protocol is practical and of great efficiency, meanwhile, it satisfies every desired security require ments for key agreement protocols.
基金Supported by the National Natural Science Foundation of China (19501032)
文摘Certificateless public key cryptography was introduced to overcome the key escrow limitation of the identity-based cryptography. It combines the advantages of the identity-based cryptography and the traditional PKI. Many certificateless public key encryption and signature schemes have been proposed. However, the key agreement in CL-PKE is seldom discussed. In this paper, we present a new certificateless two party authentication key agreement protocol and prove its security attributes. Compared with the existing protocol, our protocol is more efficient.
基金jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20060102)the International Partnership Program of Chinese Academy of Sciences(134111KYSB20160031)+2 种基金the National Natural Science Foundation of China(41330423,41905064)China Postdoctoral Science Foundation(2018M641450)the support from the Jiangsu Collaborative Innovation Center for Climate Change.
文摘Precipitation-related extremes are among the most impact-relevant consequences of a warmer climate,particularly for China,a region vulnerable to global warming and with a large population.Understanding the impacts and risks induced by future extreme precipitation changes is critical for mitigation and adaptation planning.Here,extreme precipitation changes under different levels of global warming and their associated impacts on populations in China are investigated using multimodel climate projections from the Coupled Model Intercomparison Project Phase 5 and population projections under Shared Socioeconomic Pathways.Heavy precipitation would intensify with warming across China at a rate of 6.52%(5.22%-8.57%)per degree of global warming.The longest dry spell length would increase(decrease)south(north)of-34°N.The low warming target of the Paris Agreement could substantially reduce the extreme precipitation related impacts compared to higher warming levels.For the area weighted average changes,the intensification in wet extremes could be reduced by 3.22%,9.42%and 16.70%over China,and the lengthening of dry spells could be reduced by 0.72%,4.75%and 5.31%in southeastern China,respectively,if global warming is limited to 1.5℃as compared to 2,3 and 4℃The Southeastern China is the hotspot of enhanced impacts due to the dense population.The impacts on populations induced by extreme precipitation changes are dominated by climate change,while future population redistribution plays a minor role.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 60674050, 60736022, 10972002, 60774089)the 11-5 Project(Grant No. A2120061303)
文摘This paper investigates the controllability of multi-agent systems based on agreement protocols. First, for a group of single-integrator agents, the controllability is studied in a unified framework for both networks with leader-following structure and networks with undirected graph. Some new necessary/sufficient conditions for the controllability of networks of single-integrator agents are established. Second, we prove that, under the same topology and same prescribed leaders, a network of high-order dynamic agents is completely controllable if and only if so is a network of single-integrator agents. Third, how the selection of leaders and the coupling weights of graphs affect the controllability is analyzed. Finally, some numerical simulations are presented to demonstrate the effectiveness of the theoretical results.
文摘目的通过对3种血压测量方法进行比较,为家庭自测血压用于临床和科研积累经验和科学数据。方法利用"代用盐对高血压患者及其家庭成员降压效果随机双盲对照试验研究"中收集的同一研究对象(n=220)不同方法获得血压(门诊血压、家庭自测血压和动态血压)测量数据,以动态血压数据作为参照,比较家庭血压及门诊血压与动态血压的一致性。干预前,217人3种血压测量方法数据均合格;干预结束时,189人3种血压测量方法数据均合格;将干预前和干预结束时测量合格的数据合并分析(n=406)。利用Bland-Altman对3种测量方法测得的血压水平进行组内一致性检验,并进行Person相关性分析;利用McNemar卡方检验比较3种方法的个体内一致率。结果门诊血压、动态血压和家庭自测血压3种方法测得的血压水平(收缩压/舒张压)分别为(149.5±16.4)/ (87.2±9.5)、(137.8±17.1)/(83.2±10.3)和(138.0±14.2)/(82.4±9.3)mm Hg。家庭血压与动态血压的相关性优于门诊血压与动态血压的相关性,相关系数(收缩压/舒张压)分别为(0.55/0.62)和(0.36/0.46)。以动态血压为参照,家庭自测血压水平与动态血压(收缩压/舒张压)差异无统计学意义(-0.2/-0.7 mm Hg,P>0.05),而门诊血压水平显著高于动态血压水平(11.7/4.0 mm Hg,P<0.05);家庭自测血压的收缩压个体内差异显著优于门诊血压(≤|5| mm Hg为28.3%vs 1 6.5%,P<0.05;≤|10| mm Hg为49.7%vs 33.5%,P<0.05),舒张压个体差异略高于门诊血压,但差异无统计学意义(P>0.05)。结论与动态血压测量值相比,家庭自测血压比门诊血压更准确。
基金Supported by A Grant from the National Center for Global Health and Medicine
文摘AIM:To validate the usefulness of screening endoscopy findings for predictingHelicobacter pylori (H. pylori) infection status. METHODS:H. pylori infection status was determined by histology, serology, and the urea breast test in 77 consecutive patients who underwent upper endoscopy. Based on the findings, patients were categorized as H. pylori -uninfected, -infected, or -eradicated cases. Using six photos of certain sites in the stomach per case, we determined the presence or absence of the following endoscopic findings:regular arrangement of collecting venules (RAC), linear erythema, hemorrhage, fundic gland polyp (FGP), atrophic change, rugal hyperplasia, edema, spotty erythema, exudate, xanthoma, and mottled patchy erythema (MPE). The diagnostic odds ratio (DOR) and inter-observer agreement (Kappa value) for these 11 endoscopic findings used in the determination of H. pylori infection status were calculated. RESULTS:Of the 77 patients [32 men and 45 women; mean age (SD), 39.7 (13.4) years] assessed, 28 were H. pylori uninfected, 28 were infected, and 21 were eradicated. DOR values were significantly high (< 0.05) for the following H. pylori cases:uninfected cases with RAC (11.5), linear erythema (24.5), hemorrhage (4.1), and FGP (34.5); for infected cases with atrophic change (8.67), rugal hyperplasia (15.8), edema (14.2), spotty erythema (11.5), and exudate (3.52); and for eradicated cases with atrophic change (32.4) and MPE (103.0). Kappa values were excellent for FGP (0.93), good for RAC (0.63), hemorrhage (0.79), atrophic change (0.74), and MPE (0.75), moderate for linear erythema (0.51), rugal hyperplasia (0.49), edema (0.58), spotty erythema (0.47), and exudate (0.46), and poor for xanthoma (0.19). CONCLUSION:The endoscopic findings of RAC, hemorrhage, FGP, atrophic change, and MPE will be useful for predicting H. pylori infection status.
基金This project is supported by National Natural ScienceFoundation of China Innovative Research Groups Program‘Research on Chinese Public Policy Theory and GovernanceMechanism’(71721002)The Clean DevelopmentMechanism Funding Program‘Study on the Possibility ofChina's Early Emission Peak in the Context of Global Low-Carbon Development’(2013081)。
文摘Pursuant to the Paris Agreement,China committed itself to peak its carbon emissions by around 2030 and to increase the non-fossil share ofprimary energy to 20%at the same time.The government has supported the international agreement by setting and strengthening the domesticpolicy targets for an earlier peak and faster reduction,aiming to contain the average global temperature increase to well below 2℃.We developa Kaya Inequality method to assess the time of peak and pace of reduction of China's energy-related CO2emissions based on the national energypolicy targets for 2030.We find that,despite the minor fluctuations,the current plateau essentially represents the peak emissions and should entera phase of steady decline by around 2025,given current trends in energy consumption and decarbonization.Such developments would beconsistent with the strengthened national policy target to achieve 50%of renewable power generation by 2030.However,the basic policy targetsea 20%share of non-fossil energy and 6 Gtce in total energy consumption by 2030ewould be insufficient to peak carbon emissions by around 2030.The synergy and interplay between domestic policy target setting and international climate commitments shed light on the need to elevatenational climate ambitions under the Paris Agreement and beyond.
