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A Throughput-Driven Scheduling Algorithm of Differentiated Service for Web Cluster 被引量:1
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作者 YAN Cai-rong SHEN Jun-yi PENG Qin-ke WAN Yong-quan 《Wuhan University Journal of Natural Sciences》 EI CAS 2006年第1期88-92,共5页
Requests distribution is an key technology for Web cluster server. This paper presents a throughput-driven scheduling algorithm (TDSA). The algorithm adopts the throughput of cluster back-ends to evaluate their load... Requests distribution is an key technology for Web cluster server. This paper presents a throughput-driven scheduling algorithm (TDSA). The algorithm adopts the throughput of cluster back-ends to evaluate their load and employs the neural network model to predict the future load so that the scheduling system features a self-learning capability and good adaptability to the change of load. Moreover, it separates static requests from dynamic requests to make full use of the CPU resources and takes the locality of requests into account to improve the cache hit ratio. Experimental re suits from the testing tool of WebBench^TM show better per formance for Web cluster server with TDSA than that with traditional scheduling algorithms. 展开更多
关键词 Web cluster server throughput-driven scheduling algorithm differentiated service
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ECC:Edge Collaborative Caching Strategy for Differentiated Services Load-Balancing 被引量:1
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作者 Fang Liu Zhenyuan Zhang +1 位作者 Zunfu Wang Yuting Xing 《Computers, Materials & Continua》 SCIE EI 2021年第11期2045-2060,共16页
Due to the explosion of network data traffic and IoT devices,edge servers are overloaded and slow to respond to the massive volume of online requests.A large number of studies have shown that edge caching can solve th... Due to the explosion of network data traffic and IoT devices,edge servers are overloaded and slow to respond to the massive volume of online requests.A large number of studies have shown that edge caching can solve this problem effectively.This paper proposes a distributed edge collaborative caching mechanism for Internet online request services scenario.It solves the problem of large average access delay caused by unbalanced load of edge servers,meets users’differentiated service demands and improves user experience.In particular,the edge cache node selection algorithm is optimized,and a novel edge cache replacement strategy considering the differentiated user requests is proposed.This mechanism can shorten the response time to a large number of user requests.Experimental results show that,compared with the current advanced online edge caching algorithm,the proposed edge collaborative caching strategy in this paper can reduce the average response delay by 9%.It also increases the user utility by 4.5 times in differentiated service scenarios,and significantly reduces the time complexity of the edge caching algorithm. 展开更多
关键词 Edge collaborative caching differentiated service cache replacement strategy load balancing
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AN ADAPTIVE AQM TO PROVIDE DELAY GUARANTEES FOR DIFFERENTIATED SERVICES 被引量:1
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作者 Yang Zongkai Liu Wei +1 位作者 He Jianhua Chou Chuntung 《Journal of Electronics(China)》 2005年第6期619-631,共13页
RIO(RED with IN and OUT) is the primary queue management mechanism proposed for assured forwarding in the DiffServ (Differentiated Service) framework. Although RIO can generally provide bandwidth guarantees, its queui... RIO(RED with IN and OUT) is the primary queue management mechanism proposed for assured forwarding in the DiffServ (Differentiated Service) framework. Although RIO can generally provide bandwidth guarantees, its queuing delay is sensitive to the traffic load. This paper presents a qualitative explanation for its origin. As a solution, an Adaptive RIO for Delay (ARIO-D) is proposed to provide guaranteed delay for multimedia traffic. Simulation results show that by trading loss for delay, ARIO-D can effectively improve the robustness of RIO under different and dynamic traffic, and provide stable and differentiated performance of queuing delay without any degradation in performance of throughput. 展开更多
关键词 differentiated services Adaptive RIO (RED with IN and OUT) Delay guarantees
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Differentiated payments for environmental services schemes: A methodology proposal
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作者 Carlos R.AGUILAR-GóMEZ Sergio FRANCO-MAASS Tizbe T.ARTEAGA-REYES 《Journal of Mountain Science》 SCIE CSCD 2018年第8期1693-1710,共18页
Payment schemes for environmental services face serious budget constraints in Mexico. Payments are equally distributed among forest owners, and the governmental agencies that make payments to beneficiaries do not eval... Payment schemes for environmental services face serious budget constraints in Mexico. Payments are equally distributed among forest owners, and the governmental agencies that make payments to beneficiaries do not evaluate the amount of environmental services produced by forested areas. This lack of evaluation could lead to economic and environmental deficiencies that restrict the possible benefits of such programmes. In general, these programmes do not achieve their conservation objectives, and local beneficiaries are not involved in the design or application of these programmes. Similarly, the Payments for Hydrological Environmental Services(PHES) programme of the State of Mexico, Mexico, makes equal payments to beneficiaries of forested areas considering tree density. The objective of the present work was to create a methodology for determining differentiated payments schemes for hydrological environmental services, prioritising areas that contribute the most to groundwater recharge and promote the participation of society. In the Nevado de Toluca Natural Protected Area, the environmental criteria of forest type, tree density and aquifer overexploitation as well as social participation were considered in a multi-criteria analysis implemented in a Geographic Information System. A methodology was developed to determine differentiated payments based on specific forest characteristics that influence the potential capacity of forests to recharge groundwater reserves in addition to the level of social participation. In particular, social participation is key as it could ensure the viability of PHES programmes as conservation alternatives in forested areas with high groundwater recharge potential. 展开更多
关键词 differentiated payments Environmental services Mountain systems Multi-criteria analysis Social participation
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Research of MPLS traffic engineering over differentiated services
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作者 Yang Hu, Yang Yang, and Weidong HaoInformation Engineering School, University of Science and Technology Beijing, Beijing 100083, China 《Journal of University of Science and Technology Beijing》 CSCD 2002年第6期474-477,共4页
An approach to traffic engineering that uses differentiated services (DS) andmulti-protocol label switching (MPLS) to provide quantitative network quality of service (QoS)guarantees over an IP network was proposed. Th... An approach to traffic engineering that uses differentiated services (DS) andmulti-protocol label switching (MPLS) to provide quantitative network quality of service (QoS)guarantees over an IP network was proposed. The traffic associated with assured forwarding (AF)Per-Hop behavior (PHB) in differentiated services enabled IP network was modeled. Furthermore, theeffect of such traffic on network resources with die objective of developing efficient trafficengineering methodologies was analyzed and the optimization problem relating to traffic engineeringin DS networks with an MPLS core was formulated. The service received by TCP and UDP flows when theyshare either a link or a MPLS traffic trunk was also compared and found that in order to benefitfrom traffic engineering, MPLS trunks should be implemented end-end (first router to last router).If some part of the network is MPLS trunk-unaware, the benefits are reduced or eliminated. 展开更多
关键词 MPLS differentiated services QOS traffic engineering
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On service differentiation in mobile Ad Hoc networks 被引量:1
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作者 张顺亮 叶澄清 《Journal of Zhejiang University Science》 EI CSCD 2004年第9期1087-1094,共8页
A network model is proposed to support service differentiation for mobile Ad Hoc networks by combining a fully distributed admission control approach and the DIFS based differentiation mechanism of IEEE802.11. It can ... A network model is proposed to support service differentiation for mobile Ad Hoc networks by combining a fully distributed admission control approach and the DIFS based differentiation mechanism of IEEE802.11. It can provide different kinds of QoS (Quality of Service) for various applications. Admission controllers determine a committed bandwidth based on the reserved bandwidth of flows and the source utilization of networks. Packets are marked when entering into networks by markers according to the committed rate. By the mark in the packet header, intermediate nodes handle the received packets in different manners to provide applications with the QoS corresponding to the pre-negotiated profile. Extensive simulation experiments showed that the proposed mechanism can provide QoS guarantee to assured service traffic and increase the channel utilization of networks. 展开更多
关键词 Mobile Ad Hoc networks IEEE802.11 DIFS service differentiation QoS (Quality of service)
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A New Self-Adapting Admission Control Algorithm for Differential Service in Web Clusters
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作者 LIUAn-feng CHENZhi-gang LONGGuo-ping 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第5期749-754,共6页
A new admission control algorithm considering the network self-similar access characteristics is proposed. Taking advantage of the mathematical model of the network traffic admission control which can effectively over... A new admission control algorithm considering the network self-similar access characteristics is proposed. Taking advantage of the mathematical model of the network traffic admission control which can effectively overcome the self-similar characteristics of the network requests, through the scheduling of the differential service qucue based on priority while at the same time taking into account various factors including access characteristics of requests, load information, etc, smoothness of the admission control is ensured by the algorithm proposed in this paper. We design a non-linear self-adapting control algorithm by introducing an exponential admission function, thus overcomes the negative aspects introduced by static threshold parameters. Simulation results show that the scheme proposed in this paper can effectively improve the resource utilization of the clusters, while at the same time protecting the service with high priority. Our simulation results also show that this algorithm can improve system stability and reliability too. Key words Web cluster - admission control - differential service - self-similar - self-adapting CLC number TP 393 Foundation item: Supported by the National Natural Science Foundation of China (10375024) and the Hunan Natural Science Foundation of China(03JJY4054)Biography: LIU An-feng(1971-), male, Ph. D candidate, majoring in network computing, Web QoS. 展开更多
关键词 Web cluster admission control differential service SELF-SIMILAR self-adapting
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Optimization Model Proposal for Traffic Differentiation in Wireless Sensor Networks
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作者 Adisa Haskovic Dzubur Samir Causevic +3 位作者 Belma Memic Muhamed Begovic Elma Avdagic-Golub Alem Colakovic 《Computers, Materials & Continua》 SCIE EI 2024年第10期1059-1084,共26页
Wireless sensor networks(WSNs)are characterized by heterogeneous traffic types(audio,video,data)and diverse application traffic requirements.This paper introduces three traffic classes following the defined model of h... Wireless sensor networks(WSNs)are characterized by heterogeneous traffic types(audio,video,data)and diverse application traffic requirements.This paper introduces three traffic classes following the defined model of heterogeneous traffic differentiation in WSNs.The requirements for each class regarding sensitivity to QoS(Quality of Service)parameters,such as loss,delay,and jitter,are described.These classes encompass real-time and delay-tolerant traffic.Given that QoS evaluation is a multi-criteria decision-making problem,we employed the AHP(Analytical Hierarchy Process)method for multi-criteria optimization.As a result of this approach,we derived weight values for different traffic classes based on key QoS factors and requirements.These weights are assigned to individual traffic classes to determine transmission priority.This study provides a thorough comparative analysis of the proposed model against existing methods,demonstrating its superior performance across various traffic scenarios and its implications for future WSN applications.The results highlight the model’s adaptability and robustness in optimizing network resources under varying conditions,offering insights into practical deployments in real-world scenarios.Additionally,the paper includes an analysis of energy consumption,underscoring the trade-offs between QoS performance and energy efficiency.This study presents the development of a differentiated services model for heterogeneous traffic in wireless sensor networks,considering the appropriate QoS framework supported by experimental analyses. 展开更多
关键词 Wireless Sensor Networks(WSNs) traffic differentiation traffic classes Quality of services(QoS) multi-criteria optimization Analytical Hierarchy Process(AHP)
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Improvements on Analytical Models for IEEE 802.11e EDCF Differential Services
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作者 张连波 方旭明 单瑛 《Journal of Southwest Jiaotong University(English Edition)》 2006年第3期218-222,共5页
Zhu introduced typical analytical models to simulate the 802. 11e EDCF channel access protocol. But our analysis indicates that there are some inaccurate derivations in his presentation. This paper intends to improve ... Zhu introduced typical analytical models to simulate the 802. 11e EDCF channel access protocol. But our analysis indicates that there are some inaccurate derivations in his presentation. This paper intends to improve analytical model with some corrections. Furthermore, for the probability of the channel being busy pb in Zhu's model, different points and analysis method are proposed. When the network is under saturation condition, the new results about the probabilities of collision and channel busy, transmission probabilities, successful transmission probabilities, throughput and MAC layer latency are presented. 展开更多
关键词 802.11e HDCF PERFORMANCE ANALYSIS differential services
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一种基于Web Service的分级QoS的研究与实现 被引量:12
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作者 徐明伟 胡春明 +1 位作者 刘旭东 马殿富 《计算机研究与发展》 EI CSCD 北大核心 2005年第4期669-675,共7页
随着WebService技术的广泛应用,QoS成为一个非常重要的问题.以服务响应时间为QoS参数,验证了一种基于WebService的分级QoS方法,提出了目标时间预设模型,并针对优化问题提出一种基于动态规划的解决方法,并实现了原型系统.实验数据表明这... 随着WebService技术的广泛应用,QoS成为一个非常重要的问题.以服务响应时间为QoS参数,验证了一种基于WebService的分级QoS方法,提出了目标时间预设模型,并针对优化问题提出一种基于动态规划的解决方法,并实现了原型系统.实验数据表明这种方法有效地控制了负载平衡,实现了服务分级. 展开更多
关键词 WEB服务质量 服务分级 服务水平协商 权重循环 响应时间 WEB服务
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Spatial Pattern and Heterogeneity of Port & Shipping Service Enterprises in the Yangtze River Delta,2002–2016
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作者 CAO Youhui JIANG Ziran +2 位作者 YE Shilin WU Wei LIANG Shuangbo 《Chinese Geographical Science》 SCIE CSCD 2019年第3期474-487,共14页
Using the ‘theoretical hypothesis—empirical study—case verification' method, this paper studies the spatial distribution and differentiation of port & shipping service enterprises(PSSE), as well as the vari... Using the ‘theoretical hypothesis—empirical study—case verification' method, this paper studies the spatial distribution and differentiation of port & shipping service enterprises(PSSE), as well as the variation process and underlying mechanism in the Yangtze River Delta(YRD). First, through inductive and deductive reasoning, we propose the following hypothesis: the regional distribution of different types of PSSE would show different spatial agglomeration-decentralization tendency; and there would be distinct regional differentiation in the industrial structure of the enterprises. Second, based on data obtained from enterprises, empirical research is conducted using Gini coefficient and spatial interpolation simulation methods. Results show that: 1) The overall enterprise distribution is decentralized within a city. 2) Different types of enterprises show different spatial agglomeration-decentralization tendencies. At 3000 m×3000 m grid scale, there is an agglomeration tendency along seas and rivers in the spatial distribution of enterprises. Shanghai has been identified consistently as a hot spot. 3) There is significant regional differentiation in 12 port cities with respect to the industrial structures of enterprises. Finally, the transportization and the increase of shipping service demand, the globalization and the expansion of multinational corporate activities, the hierarchization and the cooperation among port cities as well as the decentralization and the behavioral difference between the central and local states can be seen as main driving mechanism of the spatial phenomenon. 展开更多
关键词 PORT & SHIPPING service ENTERPRISES spatial distribution regional differentiation HUB PORT city YANGTZE River Delta
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The Ghana Project in Psychiatry: A Systematic Description of the Mental Health Services
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作者 Michael Atakora Mdala Ibrahim Emmanuel Asampong 《Open Journal of Psychiatry》 2020年第4期141-170,共30页
<strong>Introduction: </strong>Mental health is a neglected field within the health care system in Ghana. Studies and public education focusing on mental health remain low, leading to poor knowledge and aw... <strong>Introduction: </strong>Mental health is a neglected field within the health care system in Ghana. Studies and public education focusing on mental health remain low, leading to poor knowledge and awareness of mental health among the population. <strong>Objective:</strong> The overall aim of this study was to provide a systematic description of mental health services in Ghana. <strong>Methods:</strong> A snowball technique was used to select a total of 42 mental health professionals from six hospitals for interviews. A structured questionnaire was used for data collection. <strong>Results:</strong> Major findings of this study include inadequate human and material resources;poor knowledge of mental health among the population;weak coordination between general practitioners and mental health professionals;inadequate mental health services in schools and prisons. Additionally, 54.8% of respondents reported limited mental health educational materials, and most schools (54.8%) lacking trained resident mental health professionals. The main interventions for service delivery are taking over activities of daily living by nurses, problem assessment, and psychological interventions which achieved the same results (69%). A tendency to consult faith-based healers and prayer camps;a lack of mental health research capacity, specifically research focusing on policies;and weakness in the organization and decentralization of mental health services in Ghana are among the common challenges to seeking care. <strong>Conclusion: </strong>Public mental health education on available resources and services is important. Capacity research focusing on dissemination and implementation of mental health policies can serve as the basis for addressing mental health challenges and improving service delivery in Ghana. 展开更多
关键词 Mental Health service RESOURCES ORGANIZATION DECENTRALIZATION differentiATION
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“差序格局”特征社会网络对养老服务消费行为的影响 被引量:1
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作者 马跃如 黄尧 袁红艳 《湖南大学学报(社会科学版)》 北大核心 2024年第3期43-54,共12页
基于实地调研数据可知,“差序格局”特征社会网络对老年人养老服务消费行为的影响结果主要有:在自我与家庭层面,收入水平和子女态度是影响老年人养老服务消费意愿转化的核心因素。在社会网络层面,以广场舞、太极拳等集体性文化娱乐活动... 基于实地调研数据可知,“差序格局”特征社会网络对老年人养老服务消费行为的影响结果主要有:在自我与家庭层面,收入水平和子女态度是影响老年人养老服务消费意愿转化的核心因素。在社会网络层面,以广场舞、太极拳等集体性文化娱乐活动为代表的弱关系社会参与活动对养老服务消费意愿与行为的积极影响比以亲友关系为代表的强关系社会参与更明显,强关系在涉及日常生活安排和状态改变的养老服务消费决策中发挥重要作用。异质性分析表明:女性、高受教育程度、城市地区人群的养老服务消费意愿转化能力更强;自我层面与社会网络层面对养老服务消费行为的影响呈现出显著的城乡差异。据此,我国在实践中可通过挖掘弱关系社交核心节点带动作用、制定差异化的需求管理策略,带动潜在客群的消费行为。 展开更多
关键词 养老服务消费 差序格局 社会嵌入 弱关系
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高质量发展导向下大城市社会空间分异格局及调控策略——以广州为例 被引量:2
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作者 魏宗财 兰志懿 +2 位作者 唐琦婧 袁奇峰 黄铎 《中国名城》 2024年第2期41-51,共11页
城市社会空间分异是城乡规划领域的经典议题。以广州市为例,根据人口普查数据和人群画像数据等,聚焦城市内部各街区,通过对居住空间类型与社会群体分布和公共服务设施配置的关联分析,深入探究中心城区社会空间分异特征及现存问题,进而... 城市社会空间分异是城乡规划领域的经典议题。以广州市为例,根据人口普查数据和人群画像数据等,聚焦城市内部各街区,通过对居住空间类型与社会群体分布和公共服务设施配置的关联分析,深入探究中心城区社会空间分异特征及现存问题,进而提出城市社会空间高质量均衡发展的调控策略。研究发现,广州市中心城区在居住空间类型方面以商品房街区和城中村街区为主,老旧街区占比较小,呈现出明显的居住空间分异特征,且三类街区的居民在年龄、受教育程度、收入、消费水平等社会经济特征方面差异显著;各类公共服务设施供给水平在不同社会群体及三类街区之间亦表现出明显的不均衡性;在城市历史发展惯性、城市规划引导、房地产发展的共同影响下,广州市中心城区呈现出“圈层+斑块”的社会空间结构。为缓解中国快速城镇化进程中大城市出现的社会空间维度不均衡发展的问题,从可负担住房保障和公共服务设施布局两方面提出相关调控策略,为推动城市高质量发展提供研究支撑。 展开更多
关键词 社会空间分异 居住空间 公共服务设施 广州
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新能源汽车动力电池压差故障及维修技术探析 被引量:3
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作者 吴飞 宋文艳 王佳俊 《内燃机与配件》 2024年第3期75-77,共3页
新能源汽车动力电池压差故障是一种常见的故障问题,该故障会严重影响电池性能,不利于新能源汽车正常行驶。为解决这一问题,通过对新能源汽车动力电池压差故障与维修技术进行了分析,首先,简单介绍了新能源汽车的特点,其次,分析了新能源... 新能源汽车动力电池压差故障是一种常见的故障问题,该故障会严重影响电池性能,不利于新能源汽车正常行驶。为解决这一问题,通过对新能源汽车动力电池压差故障与维修技术进行了分析,首先,简单介绍了新能源汽车的特点,其次,分析了新能源汽车动力电池压差故障问题,包括相应的故障类型、故障原因等,最后,对新能源汽车动力电池压差故障诊断与维修技术进行了分析,系统汇总了新能源汽车动力电池压差故障诊断技术,讨论了相关的维修技术,希望能够为相关研究提供一定的参考。 展开更多
关键词 新能源汽车 动力电池 压差故障 诊断 维修
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基于策略图的三维位置隐私发布算法研究
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作者 尹春勇 贾续康 《信息网络安全》 CSCD 北大核心 2024年第4期602-613,共12页
随着移动智能终端的普及,基于位置服务(Location-Based Services,LBS)的应用迎来了爆发式增长,高层室内建筑是位置服务的重要应用场景之一。然而现有的位置隐私保护算法大多适用于二维位置数据,面向大型室内三维场景的位置隐私保护研究... 随着移动智能终端的普及,基于位置服务(Location-Based Services,LBS)的应用迎来了爆发式增长,高层室内建筑是位置服务的重要应用场景之一。然而现有的位置隐私保护算法大多适用于二维位置数据,面向大型室内三维场景的位置隐私保护研究尚且不足,并且缺乏可个性化定制的三维隐私策略。针对该问题,文章提出了一种基于策略图的三维位置隐私发布算法。首先,设计一种基于可定制策略图的位置隐私保护框架,可根据具体场景需求动态定制适合的隐私策略;其次,设计两种面向三维的差分隐私变体机制,结合定制策略图,实现三维场景下的位置隐私保护;最后,在三维数据集上进行仿真实验,实验结果表明,与其他三维位置隐私保护算法相比,文章所提算法具有更好的稳定性和效用性。 展开更多
关键词 高层室内场景 三维位置隐私 策略图 差分隐私 基于位置服务
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三维激光扫描技术在隧道运营状态评价中的应用
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作者 吴乃龙 王钰双 《城市勘测》 2024年第4期176-179,183,共5页
为评价地铁隧道运营状态,该文利用三维激光扫描点云数据,通过对点云数据预处理、椭圆模型拟合,结合隧道差异沉降测量成果,获取隧道结构几何尺寸变化病害;通过对隧道现状病害判读分析,得到隧道外观病害。根据病害检测成果结合隧道设计资... 为评价地铁隧道运营状态,该文利用三维激光扫描点云数据,通过对点云数据预处理、椭圆模型拟合,结合隧道差异沉降测量成果,获取隧道结构几何尺寸变化病害;通过对隧道现状病害判读分析,得到隧道外观病害。根据病害检测成果结合隧道设计资料,对隧道结构状况和行车影响进行评价。最后,以福州地铁6号线林樟区间现状检测项目为例,结合隧道运营状态评价方法对其进行了评价。 展开更多
关键词 三维激光 病害检测 差异沉降 服役评价
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京津风沙源生态系统服务时空分布及冷热点分析 被引量:1
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作者 常瑨予 武志涛 +4 位作者 李琪 梁寒雪 杜自强 雷添杰 孙斌 《水土保持学报》 CSCD 北大核心 2024年第3期216-226,共11页
[目的]为明晰京津风沙源区生态系统服务时空格局特征及识别其冷热点,评估京津风沙源区实施生态工程后的生态效益及生态影响。[方法]基于京津风沙源区2000—2017年的遥感、气象、土壤、土地利用等数据,利用CASA(carnegie-ames-stanford a... [目的]为明晰京津风沙源区生态系统服务时空格局特征及识别其冷热点,评估京津风沙源区实施生态工程后的生态效益及生态影响。[方法]基于京津风沙源区2000—2017年的遥感、气象、土壤、土地利用等数据,利用CASA(carnegie-ames-stanford approach)模型、InVEST(integrated valuation of ecosystem services and trade offs)模型、RWEQ(revised wind erosion equation)模型和RUSLE(revised universal soil loss equation)模型分别估算产水量、土壤保持、固碳和防风固沙服务,采用Getis-Ord Gi~*统计指数方法,识别京津风沙源区生态系统服务冷热点区域。[结果](1)2000—2017年各项生态系统服务功能均呈现上升趋势,4项生态系统服务功能的高值区集中在研究区的东南部,低值区集中在研究区的西北部。(2)2000—2017年4项生态系统服务均在京津风沙源西南部的鄂尔多斯高原沙化土地治理区出现明显的热点面积增加现象;固碳服务热点区域面积显著增加,其中,浑善达克-科尔沁沙地沙化土地治理区和坝上高原及华北北部丘陵山地水源涵养治理区的冷点区域向热点区域转化;产水服务冷热点面积占比没有明显变化,热点区主要集中在研究区南部坝上高原及华北北部丘陵山地水源涵养治理区,冷点区分布较为零散;防风固沙服务冷点区域面积增加;土壤保持服务冷热点区域面积占比很小且变化不大,区域土壤保持供给能力比较平均。(3)多重生态系统服务结果显示,研究区东南部区域能够提供2项及以上的高值生态系统服务功能,属于重点生态系统服务功能供给区,约占整个研究区15.5%。(4)2000—2017年林地4项生态系统服务热点面积占比较高,草地和林地的固碳服务功能热点面积显著增加,林地可提供较高的综合生态系统服务功能。[结论]京津风沙源治理工程的实施使得区域内总体生态系统服务功能提升。研究结果可为评估京津风沙源治理工程恢复成效提供一定科学数据,最终实现京津地区生态环境的可持续发展。 展开更多
关键词 生态系统服务 热点分析 时空分异 京津风沙源
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车联网中基于位置语义的差分隐私保护方法 被引量:1
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作者 解杉杉 刘海龙 赵国生 《小型微型计算机系统》 CSCD 北大核心 2024年第4期984-990,共7页
车联网中车辆获取基于位置服务时需要提供真实的位置信息,导致用户的轨迹隐私存在泄漏风险.针对车联网轨迹隐私保护中未考虑位置语义信息及生成的虚假轨迹可用性低问题,提出一种基于位置语义的差分隐私轨迹保护方法.首先,根据语义流行... 车联网中车辆获取基于位置服务时需要提供真实的位置信息,导致用户的轨迹隐私存在泄漏风险.针对车联网轨迹隐私保护中未考虑位置语义信息及生成的虚假轨迹可用性低问题,提出一种基于位置语义的差分隐私轨迹保护方法.首先,根据语义流行度和信息熵计算出真实位置对隐私预算的敏感程度,并设计实时隐私等级计算算法,同时搭建差分隐私模型实时分配隐私预算.然后划分语义Voronoi地图,对具有相同语义的虚假位置使用K-means算法进行聚类,并使用Hausdorff距离衡量轨迹相似度,以提升轨迹的可用性.在真实数据集上的仿真实验表明,所提方法与其他差分隐私保护方法相比轨迹可用性有明显的提升. 展开更多
关键词 车联网 基于位置服务 轨迹隐私 位置语义 差分隐私
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DiffServ Over MPLS模型实现机制研究 被引量:9
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作者 喻钢 吴产乐 +2 位作者 朱怀东 徐崴 吴梦晓 《武汉大学学报(理学版)》 CAS CSCD 北大核心 2003年第1期59-62,共4页
讨论了DiffServOverMPLS模型以及模型的实现机制 ,给出了DiffServOverMPLS模型中标记交换边缘路由器LER和标记交换路由器LSR的实现框架 ,详细论述了框架中的各组件的功能 .
关键词 diffserv OVER MPLS模型 实现机制 多协议标记交换 区分服务 逐跳行为 服务映射 PHB调度类 IP网络
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