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Definability and Textural Rough Set Algebras
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作者 DIKER Murat 《浙江海洋学院学报(自然科学版)》 CAS 2010年第5期428-439,共12页
In this paper,a counterpart of definability is studied in texture spaces.The concept of textural complete field is defined and the relations with textural definable sets are investigated.If a texture is discrete,then ... In this paper,a counterpart of definability is studied in texture spaces.The concept of textural complete field is defined and the relations with textural definable sets are investigated.If a texture is discrete,then textural definability coincides with definability.Using this fact,we obtain some basic results for definability in rough set algebras.Further,we discuss on definability for fuzzy rough sets considering textural fuzzy direlations. 展开更多
关键词 Approximation operator complete field of sets definability direlation fuzzy rough set rough set textural complete field of sets textural rough set texture space
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A Decentralized and TCAM-Aware Failure Recovery Model in Software Defined Data Center Networks
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作者 Suheib Alhiyari Siti Hafizah AB Hamid Nur Nasuha Daud 《Computers, Materials & Continua》 SCIE EI 2025年第1期1087-1107,共21页
Link failure is a critical issue in large networks and must be effectively addressed.In software-defined networks(SDN),link failure recovery schemes can be categorized into proactive and reactive approaches.Reactive s... Link failure is a critical issue in large networks and must be effectively addressed.In software-defined networks(SDN),link failure recovery schemes can be categorized into proactive and reactive approaches.Reactive schemes have longer recovery times while proactive schemes provide faster recovery but overwhelm the memory of switches by flow entries.As SDN adoption grows,ensuring efficient recovery from link failures in the data plane becomes crucial.In particular,data center networks(DCNs)demand rapid recovery times and efficient resource utilization to meet carrier-grade requirements.This paper proposes an efficient Decentralized Failure Recovery(DFR)model for SDNs,meeting recovery time requirements and optimizing switch memory resource consumption.The DFR model enables switches to autonomously reroute traffic upon link failures without involving the controller,achieving fast recovery times while minimizing memory usage.DFR employs the Fast Failover Group in the OpenFlow standard for local recovery without requiring controller communication and utilizes the k-shortest path algorithm to proactively install backup paths,allowing immediate local recovery without controller intervention and enhancing overall network stability and scalability.DFR employs flow entry aggregation techniques to reduce switch memory usage.Instead of matching flow entries to the destination host’s MAC address,DFR matches packets to the destination switch’s MAC address.This reduces the switches’Ternary Content-Addressable Memory(TCAM)consumption.Additionally,DFR modifies Address Resolution Protocol(ARP)replies to provide source hosts with the destination switch’s MAC address,facilitating flow entry aggregation without affecting normal network operations.The performance of DFR is evaluated through the network emulator Mininet 2.3.1 and Ryu 3.1 as SDN controller.For different number of active flows,number of hosts per edge switch,and different network sizes,the proposed model outperformed various failure recovery models:restoration-based,protection by flow entries,protection by group entries and protection by Vlan-tagging model in terms of recovery time,switch memory consumption and controller overhead which represented the number of flow entry updates to recover from the failure.Experimental results demonstrate that DFR achieves recovery times under 20 milliseconds,satisfying carrier-grade requirements for rapid failure recovery.Additionally,DFR reduces switch memory usage by up to 95%compared to traditional protection methods and minimizes controller load by eliminating the need for controller intervention during failure recovery.Theresults underscore the efficiency and scalability of the DFR model,making it a practical solution for enhancing network resilience in SDN environments. 展开更多
关键词 Software defined networking failure detection failure recovery RESTORATION protection TCAM size
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A Survey of Link Failure Detection and Recovery in Software-Defined Networks
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作者 Suheib Alhiyari Siti Hafizah AB Hamid Nur Nasuha Daud 《Computers, Materials & Continua》 SCIE EI 2025年第1期103-137,共35页
Software-defined networking(SDN)is an innovative paradigm that separates the control and data planes,introducing centralized network control.SDN is increasingly being adopted by Carrier Grade networks,offering enhance... Software-defined networking(SDN)is an innovative paradigm that separates the control and data planes,introducing centralized network control.SDN is increasingly being adopted by Carrier Grade networks,offering enhanced networkmanagement capabilities than those of traditional networks.However,because SDN is designed to ensure high-level service availability,it faces additional challenges.One of themost critical challenges is ensuring efficient detection and recovery from link failures in the data plane.Such failures can significantly impact network performance and lead to service outages,making resiliency a key concern for the effective adoption of SDN.Since the recovery process is intrinsically dependent on timely failure detection,this research surveys and analyzes the current literature on both failure detection and recovery approaches in SDN.The survey provides a critical comparison of existing failure detection techniques,highlighting their advantages and disadvantages.Additionally,it examines the current failure recovery methods,categorized as either restoration-based or protection-based,and offers a comprehensive comparison of their strengths and limitations.Lastly,future research challenges and directions are discussed to address the shortcomings of existing failure recovery methods. 展开更多
关键词 Software defined networking failure detection failure recovery RESTORATION PROTECTION
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AI-Defined Mobility in Spotlight at 2025 Shanghai Auto Show--China is leading the development of the next generation intelligent-vehicle technologies
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作者 LI YIN 《ChinAfrica》 2025年第6期59-59,共1页
The 2025 Shanghai Auto Show reaffirmed its role as one of the world’s most influential automotive industry events,offering a panoramic view of the future shaped by intelligent and electrified vehicles.With over 200 n... The 2025 Shanghai Auto Show reaffirmed its role as one of the world’s most influential automotive industry events,offering a panoramic view of the future shaped by intelligent and electrified vehicles.With over 200 new models on display-85 percent of them new energy vehicles-this year’s show spotlighted how the global auto industry is pivoting rapidly towards an era of software-defined and AI-powered mobility. 展开更多
关键词 shanghai auto show software defined mobility ai defined mobility intelligent vehicle technologies ai powered mobility new energy vehicles intelligent electrified vehicles
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The Rise of Song Studies:A Reflection of the Continuity and Creativity of Chinese Civilization
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作者 Cai Fanglu Xiao Yujie 《Contemporary Social Sciences》 2025年第1期102-119,共18页
Continuity is the foremost defining characteristic of Chinese civilization.It ensures that the evolution of this civilization respects the fine traditions and stays on the right course throughout its creative course.M... Continuity is the foremost defining characteristic of Chinese civilization.It ensures that the evolution of this civilization respects the fine traditions and stays on the right course throughout its creative course.Meanwhile,creativity imparts ceaseless vitality to this civilization,serving as the intrinsic propulsive force that fuels its evolution.The rise of Song Studies marks one of the symbolic events in the transformation in the Chinese ideological and cultural realm.It encapsulates the dialectical unity between continuity and creativity that characterizes Chinese civilization.Song Studies adhere to the traditional classic interpretations,center the core values around“benevolence,”and pursue the way of sages,which reflect the continuity of Chinese civilization.They also embody creativity.This is manifested in the emergence of a new academic spirit that emphasizes the seeking of truth and reason,a new academic ethos that involves questioning classics in the process of their dissemination and interpreting them with one’s own insight,as well as the fusion of philosophical speculation with social practice.Conducting an integrated analysis of the defining characteristics of Chinese civilization and the rise of Song Studies helps us gain a thorough understanding of the dialectical unity between the continuity and creativity of Chinese civilization through the interactions between history and reality.It also enables us to effectively address the relationship between inheritance and transformation,as well as between maintaining core values and pursuing creativity throughout its ongoing development. 展开更多
关键词 defining characteristic of Chinese civilization CONTINUITY CREATIVITY Song Studies CONFUCIANISM Confucian orthodoxy
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Echo contrast medium:How the use of contrast echocardiography(ultrasound contrast agents)can improve patient care
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作者 Kevan English 《World Journal of Methodology》 2025年第3期32-37,共6页
Conventional echocardiography can sometimes pose a challenge to diagnosis due to sub-optimal images.Ultrasound contrast agents(UCAs)have been shown to drastically enhance imaging quality,particularly depicting the lef... Conventional echocardiography can sometimes pose a challenge to diagnosis due to sub-optimal images.Ultrasound contrast agents(UCAs)have been shown to drastically enhance imaging quality,particularly depicting the left ventricular endocardial borders.Their use during echocardiography has become a valuable tool in non-invasive diagnostics.UCAs provide higher-quality images that may ultimately reduce the length of hospital stays and improve patient care.The higher cost associated with UCAs in many situations has been an impediment to frequent use.However,when used as an initial diagnostic test,UCA during rest echocardiogram is more cost-effective than the traditional diagnostic approach,which frequently includes multiple tests and imaging studies to make an accurate diagnosis.They can be easily performed across multiple patient settings and provide optimal images that allow clinicians to make sound medical decisions.This consequently allows for better diagnostic accuracies and improvement in patient care. 展开更多
关键词 Ultrasound contrast agents ECHOCARDIOGRAPHY Myocardial perfusion ULTRASOUND Left ventricle OPTISON DEFINITY SONAZOID Lumason
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THE RELATIVE VOLUME FUNCTION AND THE CAPACITY OF SPHERE ON ASYMPTOTICALLY HYPERBOLIC MANIFOLDS
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作者 Xiaoshang JIN 《Acta Mathematica Scientia》 2025年第3期755-770,共16页
Following the work of Li-Shi-Qing, we propose the definition of the relative volume function for an AH manifold. It is not a constant function in general and we study the regularity of this function. We use this funct... Following the work of Li-Shi-Qing, we propose the definition of the relative volume function for an AH manifold. It is not a constant function in general and we study the regularity of this function. We use this function to provide an accurate characterization of the height of the geodesic defining function for the AH manifold with a given boundary metric. Furthermore, it is shown that such functions are uniformly bounded from below at infinity and the bound only depends on the dimension. In the end, we apply this function to study the capacity of balls in AH manifolds and demonstrate that the “relative p—capacity function” coincides with the relative volume function under appropriate curvature conditions. 展开更多
关键词 conformally compact relative volume geodesic defining function capacity
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Association between PM_(2.5)Chemical Constituents and Preterm Birth:The Undeniable Role of Preconception H19 Gene Variation
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作者 Yalong Wang Panpan Sun +8 位作者 Xinying Wang Junxi Zhang Xiangyu Yu Jian Chai Ruo Du Wenyi Liu Fangfang Yu Yue Ba Guoyu Zhou 《Biomedical and Environmental Sciences》 2025年第8期1016-1022,共7页
Preterm birth(PTB),defined as delivery before 37 weeks of gestation,is the most common adverse pregnancy outcome[1].PTB is a global health concern,with an estimated 13.4 million cases in 2020[1],accounting for more th... Preterm birth(PTB),defined as delivery before 37 weeks of gestation,is the most common adverse pregnancy outcome[1].PTB is a global health concern,with an estimated 13.4 million cases in 2020[1],accounting for more than one in 10 births worldwide.Compared to full-term births,PTBs are associated with a higher risk of short-and long-term complications,including bronchopulmonary dysplasia,necrotizing enterocolitis,visual impairment,and cerebral injuries[2].Despite substantial research efforts to prevent PTB,the global PTB rate has shown little improvement over the past decade[1].Therefore,identifying additional risk factors remains a critical goal in preventing PTB. 展开更多
关键词 preterm birth H gene variation chemical constituents PM PRECONCEPTION bronchopulmonary dysplasianecrotizing preterm birth ptb defined
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A Dynamic SDN-Based Address Hopping Model for IoT Anonymization
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作者 Zesheng Xi Chuan He +1 位作者 Yunfan Wang Bo Zhang 《Computer Modeling in Engineering & Sciences》 2025年第8期2545-2565,共21页
The increasing reliance on interconnected Internet of Things(IoT)devices has amplified the demand for robust anonymization strategies to protect device identities and ensure secure communication.However,traditional an... The increasing reliance on interconnected Internet of Things(IoT)devices has amplified the demand for robust anonymization strategies to protect device identities and ensure secure communication.However,traditional anonymization methods for IoT networks often rely on static identity models,making them vulnerable to inference attacks through long-term observation.Moreover,these methods tend to sacrifice data availability to protect privacy,limiting their practicality in real-world applications.To overcome these limitations,we propose a dynamic device identity anonymization framework using Moving Target Defense(MTD)principles implemented via Software-Defined Networking(SDN).In our model,the SDN controller periodically reconfigures the network addresses and routes of IoT devices using a constraint-aware backtracking algorithmthat constructs new virtual topologies under connectivity and performance constraints.This address-hopping scheme introduces continuous unpredictability at the network layer dynamically changing device identifiers,routing paths,and even network topology which thwarts attacker reconnaissance while preserving normal communication.Experimental results demonstrate that our approach significantly reduces device identity exposure and scan success rates for attackers compared to static networks.Moreover,the dynamic schememaintains high data availability and network performance.Under attack conditions it reduced average communication delay by approximately 60% vs.an unprotected network,with minimal overhead on system resources. 展开更多
关键词 Device anonymization address hopping moving target defense software defined networking cyber resilience
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A Comprehensive Study of Resource Provisioning and Optimization in Edge Computing
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作者 Sreebha Bhaskaran Supriya Muthuraman 《Computers, Materials & Continua》 2025年第6期5037-5070,共34页
Efficient resource provisioning,allocation,and computation offloading are critical to realizing lowlatency,scalable,and energy-efficient applications in cloud,fog,and edge computing.Despite its importance,integrating ... Efficient resource provisioning,allocation,and computation offloading are critical to realizing lowlatency,scalable,and energy-efficient applications in cloud,fog,and edge computing.Despite its importance,integrating Software Defined Networks(SDN)for enhancing resource orchestration,task scheduling,and traffic management remains a relatively underexplored area with significant innovation potential.This paper provides a comprehensive review of existing mechanisms,categorizing resource provisioning approaches into static,dynamic,and user-centric models,while examining applications across domains such as IoT,healthcare,and autonomous systems.The survey highlights challenges such as scalability,interoperability,and security in managing dynamic and heterogeneous infrastructures.This exclusive research evaluates how SDN enables adaptive policy-based handling of distributed resources through advanced orchestration processes.Furthermore,proposes future directions,including AI-driven optimization techniques and hybrid orchestrationmodels.By addressing these emerging opportunities,thiswork serves as a foundational reference for advancing resource management strategies in next-generation cloud,fog,and edge computing ecosystems.This survey concludes that SDN-enabled computing environments find essential guidance in addressing upcoming management opportunities. 展开更多
关键词 Cloud computing edge computing fog computing resource provisioning resource allocation computation offloading optimization techniques software defined network
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Research on Railway 5G-R Comprehensive Data Transmission Platform and Security Strategy
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作者 ZUO Zihui LIU Shipeng +2 位作者 ZHANG Ziliang ZHANG Hongchuan ZHENG Mingda(Translated) 《Chinese Railways》 2025年第1期37-43,共7页
5G-R is the main type of next-generation mobile communication system for railways,offering highly reliable broadband data transmission services for intelligent railway operations.In the light of meeting the bearing de... 5G-R is the main type of next-generation mobile communication system for railways,offering highly reliable broadband data transmission services for intelligent railway operations.In the light of meeting the bearing demands of the 5G-R network,a comprehensive data transmission platform is proposed.This platform enables unified accession for various data service systems and applies Software Defined Network(SDN)technology for dynamic routing selection and high-effective data forwarding.Based on shared key lightweight access authentication technology,two-way identity authentication is performed for mobile terminals and network-side devices,ensuring the legitimacy verification of heterogeneous terminals within the application domain. 展开更多
关键词 5G-R comprehensive data transmission platform intelligent railway Software Defined Network(SDN) access authentication
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Analysis on the Use of Special Use Level of Antibiotics among Inpatients in a Hospital
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作者 Yufen XIA Wen PENG +2 位作者 Fan FENG Liang YANG Ying LIN 《Agricultural Biotechnology》 2025年第1期53-56,61,共5页
[Objectives]This study was conducted to promote the rational use of special use level of antibiotics in clinic and delay the emergence of drug resistance.[Methods]The application of antibiotics for special use among i... [Objectives]This study was conducted to promote the rational use of special use level of antibiotics in clinic and delay the emergence of drug resistance.[Methods]The application of antibiotics for special use among inpatients of a hospital in 2019 was analyzed.The data in the drug information management system of the hospital were queried,and the collected expert consultation records of special-use antibiotics were sorted out.Indicators including the use rate of special-use antibiotics,antibiotic use density(AUD),defined daily dose system(DDDs)and defined daily dose system cost(DDDc)of each drug,the annual pathogen detection rate,disease distribution and pathogenic microorganism detection were summarized and analyzed for inpatients in the hospital retrospectively.[Results]In 2019,the average annual use rate of special-use antibiotics in the hospital was 1.53%,and the average annual use density was 1.59 DDDs.The antibiotics with the top three DDDs were imipenem and cilastatin,meropenem and cefepime.The antibiotics with the top three DDDc were voriconazole dispersible tablets,voriconazole for injection,and meropenem for injection.The average annual detection rate of microorganisms was 85.77%.The diseases were mainly diagnosed as respiratory infections such as pneumonia and secondary infections after radiotherapy and chemotherapy before medication,and the detected pathogens were mainly Candida and its subspecies,Escherichia coli,and Klebsiella and its subspecies.[Conclusions]The clinical use of special-use antibiotics in the hospital was basically reasonable,but there were still some problems.It is necessary to increase management efforts,strengthen training for relevant medical personnel,and provide management ideas for further standardizing the use of antibiotics in the hospital. 展开更多
关键词 ANTIBIOTICS Special use level Rational use of drugs Antibiotic use density Defined daily dose system Microbial inspection
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Reflections on recent advances in component-based Chinese medicine
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作者 Zi-Bin Lu 《Integrative Medicine Discovery》 2025年第13期1-2,共2页
Component-based Chinese Medicine(CCM)stands as a pivotal endeavor in modernizing traditional Chinese medicine(TCM).By integrating classical TCM theories with modern scientific methodologies,CCM aims to achieve herbal ... Component-based Chinese Medicine(CCM)stands as a pivotal endeavor in modernizing traditional Chinese medicine(TCM).By integrating classical TCM theories with modern scientific methodologies,CCM aims to achieve herbal formulas with“defined components,clarified mechanisms,and controllable quality.”This approach not only transitions TCM development from empirical tradition to evidence-based science but also positions it for global recognition.Drawing on recent advancements in CCM,this editorial explores key insights and challenges shaping its trajectory. 展开更多
关键词 modernizing traditional chinese medicine tcm clarified mechanisms modern scientific methodologiesccm component based Chinese medicine traditional Chinese medicine defined components evidence based science herbal formulas
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Right ventricular myocardial infarction due to low-voltage electric shock:a case report
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作者 Nalan Kozaci İhsan Danış +2 位作者 Ali Kemal Erenler Tayfun Anıl Demir Mustafa Avci 《Journal of Geriatric Cardiology》 2025年第12期995-997,共3页
Severe injuries due to electricity are rare,but when they occur,they may cause life-threatening conditions.In order to define the severity of electrical injuries,the most widely used classification is voltage power.In... Severe injuries due to electricity are rare,but when they occur,they may cause life-threatening conditions.In order to define the severity of electrical injuries,the most widely used classification is voltage power.Injuries are mainly classified into two categories as low voltage electrical injuries(LVEI)(<1000 V)and high voltage electrical injuries(>1000 V).Fatal injuries have been reported mostly after high-voltage electric shock.Low-voltage electricity current rarely causes severe trauma and complications. 展开更多
关键词 low voltage electrical injuries lvei high voltage electrical injuries voltage power right ventricular myocardial infarction low voltage electric shock classification electrical injuries severe electrical injuries define severity electrical injuriesthe
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一种新型的LTE-A网络切换认证协议 被引量:6
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作者 陈昕 宋亚鹏 刘志强 《电子学报》 EI CAS CSCD 北大核心 2017年第2期485-491,共7页
针对典型蜂窝网络LTE-A网络的切换认证问题,本文通过引入SDN(Software Defined Network,软件定义网络),提出了软件定义LTE-A异构网络架构,在中心控制器中共享UE(User Equipment,用户设备)的安全上下文信息,以实现简化切换认证过程,提高... 针对典型蜂窝网络LTE-A网络的切换认证问题,本文通过引入SDN(Software Defined Network,软件定义网络),提出了软件定义LTE-A异构网络架构,在中心控制器中共享UE(User Equipment,用户设备)的安全上下文信息,以实现简化切换认证过程,提高认证效率的目标.中心控制器的加入,使蜂窝与核心网通信时需要增加一次信令开销,而LTE-A网络的标准切换认证方法过于复杂,应用在软件定义LTE-A异构网络中,会产生较多的信令开销.基于代理签名的切换认证方法,使UE在验证身份时不用经过核心网,减少了信令开销.在安全性相同的情况下,基于椭圆曲线的加密体系比基于RSA的加密体系计算量更小,有利于减少中心控制器的计算压力.本文采用椭圆曲线代理签名方法,提出了一种新型的切换认证协议,并运用着色Petri网进行建模和仿真分析.仿真结果表明,该协议是有效的,且安全性更高. 展开更多
关键词 LTE-A 切换认证 SDN(Software Defined Network) 椭圆曲线代理签名 着色Petir网
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求时滞Volterra积分系统最优控制问题近似解的一个迭代算法 被引量:1
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作者 潘立平 《数学年刊(A辑)》 CSCD 北大核心 2012年第3期267-290,共24页
对一类典型的复杂系统—含多个非线性时滞的Volterra积分系统,给出其控制作用受限(硬约束)最优控制问题近似解的一个迭代算法,证明了该算法是well-defined的,并在一定的条件下证得了算法的收敛性.
关键词 时滞Volterra积分系统 近似最优控制 迭代算法 Well—Defined 收敛性
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基于云网络的SDN运维节能系统 被引量:1
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作者 张梅琼 《软件》 2021年第12期174-176,共3页
随着云网络的快速发展,其所提供的云计算和云存储服务,打破了传统物理存储和计算资源的局限制,为人们提供了更加灵活和可扩展性的云应用。本文基于云网络、采用数控分离及可编程的SDN技术综合设计了基于云网络的SDN绿色运维系统。本系... 随着云网络的快速发展,其所提供的云计算和云存储服务,打破了传统物理存储和计算资源的局限制,为人们提供了更加灵活和可扩展性的云应用。本文基于云网络、采用数控分离及可编程的SDN技术综合设计了基于云网络的SDN绿色运维系统。本系统使用RYU控制器,实现了拓扑自动发现、流量监控、网络性能评估、主动节能等模块。同时,本文所设计的系统引入代数连通度作为衡量拓扑连通性指标评估网络稳定性,在保证网络性能稳定的前提实现了基于云网络的SDN运维管理和绿色节能运行系统。 展开更多
关键词 云网络 SDN(Software Define Network) RYU 能效
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Causality Is Logically Definable—Toward an Equilibrium-Based Computing Paradigm of Quantum Agent and Quantum Intelligence (QAQI) (Survey and Research) 被引量:1
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作者 Wen-Ran Zhang Karl E. Peace 《Journal of Quantum Information Science》 2014年第4期227-268,共42页
A survey on agents, causality and intelligence is presented and an equilibrium-based computing paradigm of quantum agents and quantum intelligence (QAQI) is proposed. In the survey, Aristotle’s causality principle an... A survey on agents, causality and intelligence is presented and an equilibrium-based computing paradigm of quantum agents and quantum intelligence (QAQI) is proposed. In the survey, Aristotle’s causality principle and its historical extensions by David Hume, Bertrand Russell, Lotfi Zadeh, Donald Rubin, Judea Pearl, Niels Bohr, Albert Einstein, David Bohm, and the causal set initiative are reviewed;bipolar dynamic logic (BDL) is introduced as a causal logic for bipolar inductive and deductive reasoning;bipolar quantum linear algebra (BQLA) is introdused as a causal algebra for quantum agent interaction and formation. Despite the widely held view that causality is undefinable with regularity, it is shown that equilibrium-based bipolar causality is logically definable using BDL and BQLA for causal inference in physical, social, biological, mental, and philosophical terms. This finding leads to the paradigm of QAQI where agents are modeled as quantum enssembles;intelligence is revealed as quantum intelligence. It is shown that the enssemble formation, mutation and interaction of agents can be described as direct or indirect results of quantum causality. Some fundamental laws of causation are presented for quantum agent entanglement and quantum intelligence. Applicability is illustrated;major challenges are identified in equilibriumbased causal inference and quantum data mining. 展开更多
关键词 CAUSALITY and definability CAUSAL LOGIC CAUSAL Algebra QUANTUM AGENT QUANTUM INTELLIGENCE QUANTUM Non-Locality QUANTUM LOGIC Gate Energy-Information Conservation Laws of Causation CPT Symmetry Mind-Body Unification Growing and Aging QUANTUM Biology QUANTUM Data Mining
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可编程的网络——软件定义网络(续) 被引量:1
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作者 吴承治 罗正华 《现代传输》 2013年第5期72-79,共8页
本文描述了软件定义网络(SDN)的需求、概念及关键技术,重点分析了SDN的网络结构、OpenFlow模型和OpenFlow交换机。最后,讨论了SDN的应用。
关键词 软件定义网络(Software Defined Network SDN) OpenFlow 应用编程接口(API) 自服务指配(self-service provisioning)
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非线性光学晶体K_(3.0)Li_(2.0)Nb_(5.0)O_(15.0)的生长
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作者 宋有庭 倪代秦 吴星 《人工晶体学报》 EI CAS CSCD 北大核心 2000年第S1期65-,共1页
Potassium lithium niobate single crystal with a dimension of 20mm×15mm×30mm was grown by EFG technique in our laboratory.Compared with Czochralski method for the growth of KLN crystals,EFG technique possesse... Potassium lithium niobate single crystal with a dimension of 20mm×15mm×30mm was grown by EFG technique in our laboratory.Compared with Czochralski method for the growth of KLN crystals,EFG technique possesses the following merits.Crack of crystals can be weakened during the lowering of temperature and the crystals free of crack can be obtained.The crystals have no rotation,the growth striation caused by the rotation of the crystals can be eliminated.With action of capillary from a die hole,the convective effect of melt at solid liquid interface can be reduced,therefore the homogeneity of crystals is better than that of crystals obtained by Czochralski method.The growth striation parallels each other and is perpendicular to the growth direction,so the good blue SHG can be obtained when ground wave goes through the KLN crystals.Since capillary force does not fully counteract the convective effect,the inhomogeneity of crystals can’t completely be eliminated.The low SHG conversion efficiency of KLN crystals is mainly caused by inhomogeneneity of crystals.For the growth of incongruent melting crystals,the growth rate is limited by the rejection of impurity,this also makes homogeneity of composition become bad.In the growth of KLN crystals by EFG technique,the fluctuation of the temperature at solid liquid interface should be enough small,and the film thickness of melt should be proper.Too thick film of melt makes the process of crystal growth unstable;too thin film of melt can lead to the constitutional supercooling. 展开更多
关键词 nonlinear optical crystal K 3.0 Li 2.0 Nb 5.0 O 15.0 crystal growth edge defined film fed growth technique
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