EOR Defined as Key Problem

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Threshold-Based Software-Defined Networking(SDN)Solution for Healthcare Systems against Intrusion Attacks

The healthcare sector holds valuable and sensitive data.The amount of this data and the need to handle,exchange,and protect it,has been increasing at a fast pace.Due to their nature,software-defined networks(SDNs)are widely used in healthcare systems,as they ensure effective resource utilization,safety,great network management,and monitoring.In this sector,due to the value of thedata,SDNs faceamajor challengeposed byawide range of attacks,such as distributed denial of service(DDoS)and probe attacks.These attacks reduce network performance,causing the degradation of different key performance indicators(KPIs)or,in the worst cases,a network failure which can threaten human lives.This can be significant,especially with the current expansion of portable healthcare that supports mobile and wireless devices for what is called mobile health,or m-health.In this study,we examine the effectiveness of using SDNs for defense against DDoS,as well as their effects on different network KPIs under various scenarios.We propose a threshold-based DDoS classifier(TBDC)technique to classify DDoS attacks in healthcare SDNs,aiming to block traffic considered a hazard in the form of a DDoS attack.We then evaluate the accuracy and performance of the proposed TBDC approach.Our technique shows outstanding performance,increasing the mean throughput by 190.3%,reducing the mean delay by 95%,and reducing packet loss by 99.7%relative to normal,with DDoS attack traffic.

Deployment Strategy for Multiple Controllers Based on the Aviation On-Board Software-Defined Data Link Network

In light of the escalating demand and intricacy of services in contemporary terrestrial,maritime,and aerial combat operations,there is a compelling need for enhanced service quality and efficiency in airborne cluster communication networks.Software-Defined Networking(SDN)proffers a viable solution for the multifaceted task of cooperative communication transmission and management across different operational domains within complex combat contexts,due to its intrinsic ability to flexibly allocate and centrally administer network resources.This study pivots around the optimization of SDN controller deployment within airborne data link clusters.A collaborative multi-controller architecture predicated on airborne data link clusters is thus proposed.Within this architectural framework,the controller deployment issue is reframed as a two-fold problem:subdomain partition-ing and central interaction node selection.We advocate a subdomain segmentation approach grounded in node value ranking(NDVR)and a central interaction node selection methodology predicated on an enhanced Artificial Fish Swarm Algorithm(AFSA).The advanced NDVR-AFSA(Node value ranking-Improved artificial fish swarm algorithm)algorithm makes use of a chaos algorithm for population initialization,boosting population diversity and circumventing premature algorithm convergence.By the integration of adaptive strategies and incorporation of the genetic algorithm’s crossover and mutation operations,the algorithm’s search range adaptability is enhanced,thereby increasing the possibility of obtaining globally optimal solutions,while concurrently augmenting cluster reliability.The simulation results verify the advantages of the NDVR-IAFSA algorithm,achieve a better load balancing effect,improve the reliability of aviation data link cluster,and significantly reduce the average propagation delay and disconnection rate,respectively,by 12.8%and 11.7%.This shows that the optimization scheme has important significance in practical application,and can meet the high requirements of modern sea,land,and air operations to aviation airborne communication networks.

Open-Source Software Defined Networking Controllers:State-of-the-Art,Challenges and Solutions for Future Network Providers

Software Defined Networking(SDN)is programmable by separation of forwarding control through the centralization of the controller.The controller plays the role of the‘brain’that dictates the intelligent part of SDN technology.Various versions of SDN controllers exist as a response to the diverse demands and functions expected of them.There are several SDN controllers available in the open market besides a large number of commercial controllers;some are developed tomeet carrier-grade service levels and one of the recent trends in open-source SDN controllers is the Open Network Operating System(ONOS).This paper presents a comparative study between open source SDN controllers,which are known as Network Controller Platform(NOX),Python-based Network Controller(POX),component-based SDN framework(Ryu),Java-based OpenFlow controller(Floodlight),OpenDayLight(ODL)and ONOS.The discussion is further extended into ONOS architecture,as well as,the evolution of ONOS controllers.This article will review use cases based on ONOS controllers in several application deployments.Moreover,the opportunities and challenges of open source SDN controllers will be discussed,exploring carriergrade ONOS for future real-world deployments,ONOS unique features and identifying the suitable choice of SDN controller for service providers.In addition,we attempt to provide answers to several critical questions relating to the implications of the open-source nature of SDN controllers regarding vendor lock-in,interoperability,and standards compliance,Similarly,real-world use cases of organizations using open-source SDN are highlighted and how the open-source community contributes to the development of SDN controllers.Furthermore,challenges faced by open-source projects,and considerations when choosing an open-source SDN controller are underscored.Then the role of Artificial Intelligence(AI)and Machine Learning(ML)in the evolution of open-source SDN controllers in light of recent research is indicated.In addition,the challenges and limitations associated with deploying open-source SDN controllers in production networks,how can they be mitigated,and finally how opensource SDN controllers handle network security and ensure that network configurations and policies are robust and resilient are presented.Potential opportunities and challenges for future Open SDN deployment are outlined to conclude the article.

Review of Load Balancing Mechanisms in SDN-Based Data Centers

With the continuous expansion of the data center network scale, changing network requirements, and increasing pressure on network bandwidth, the traditional network architecture can no longer meet people’s needs. The development of software defined networks has brought new opportunities and challenges to future networks. The data and control separation characteristics of SDN improve the performance of the entire network. Researchers have integrated SDN architecture into data centers to improve network resource utilization and performance. This paper first introduces the basic concepts of SDN and data center networks. Then it discusses SDN-based load balancing mechanisms for data centers from different perspectives. Finally, it summarizes and looks forward to the study on SDN-based load balancing mechanisms and its development trend.

Multipath Selection Algorithm Based on Dynamic Flow Prediction

Traditional traffic management techniques appear to be incompetent in complex data center networks, so proposes a load balancing strategy based on Long Short-Term Memory (LSTM) and quantum annealing by Software Defined Network (SDN) to dynamically predict the traffic and comprehensively consider the current and predicted load of the network in order to select the optimal forwarding path and balance the network load. Experiments have demonstrated that the algorithm achieves significant improvement in both system throughput and average packet loss rate for the purpose of improving network quality of service.

Cryopreservation of cynomolgus monkey (Macacafascicularis)spermatozoa in a chemically defined extender

Aim:To establish a method for cynomolgus monkey sperm cryopreservation in a chemically defined extender. Methods:Semen samples were collected by electro-ejaculation from four sexually mature male cynomolgus monkeys. The spermatozoa were frozen in straws by liquid nitrogen vapor using egg-yolk-free Tes-Tris (mTTE) synthetic extender and glycerol as cryoprotectant.The effects of glycerol concentration (1%,3 %,5 %,10 % and 15 % [v/v]) and its equilibration time (10 min,30 min,60 min and 90 min) on post-thaw spermatozoa were examined by sperm motility and sperm head membrane integrity.Results:The post-thaw motility and head membrane integrity of spermatozoa were significantly higher (P<0.05) for 5 % glycerol (42.95±2.55 and 50.39±2.42,respectively) than those of the other groups (1%:19.19±3.22 and 24.84±3.64;3 %:34.23±3.43 and 41.37±3.42;10 %: 15.68±2.36 and 21.39±3.14;15 %:7.47±1.44 and 12.90±2.18).The parameters for 30 min equilibration (42.95±2.55 and 50.39±2.42) were better (P<0.05) than those of the other groups (10 min:31.33±3.06 and 38. 98±3.31;60 min:32.49±3.86 and 40.01±4.18;90 min:31.16±3.66 and 38.30±3.78).Five percent glycerol and 30 min equilibration yielded the highest post-thaw sperm motility and head membrane integrity.Conclusion: Cynomolgus monkey spermatozoa can be successfully cryopreserved in a chemically defined extender,which is related to the concentration and the equilibration time of glycerol.

Blockchain-Based Secure Distributed Control for Software Defined Optical Networking

Software defined optical networking(SDON)is a critical technology for the next generation network with the advantages of programmable control and etc.As one of the key issues of SDON,the security of control plane has also received extensive attention,especially in certain network scenarios with high security requirement.Due to the existence of vulnerabilities and heavy overhead,the existing firewalls and distributed control technologies cannot solve the control plane security problem well.In this paper,we propose a distributed control architecture for SDON using the blockchain technique(BlockCtrl).The proposed BlockCtrl model introduces the advantages of blockchain into SDON to achieve a high-efficiency fault tolerant control.We have evaluated the performance of our proposed architecture and compared it to the existing models with respect to various metrics including processing rate,recovery latency and etc.The numerical results show that the BlockCtrl is capable of attacks detection and fault tolerant control in SDON with high performance on resource utilization and service correlation.

A Methodology for Reliability of WSN Based on Software Defined Network in Adaptive Industrial Environment

As communication technology and smart manufacturing have developed, the industrial internet of things(IIo T)has gained considerable attention from academia and industry.Wireless sensor networks(WSNs) have many advantages with broad applications in many areas including environmental monitoring, which makes it a very important part of IIo T. However,energy depletion and hardware malfunctions can lead to node failures in WSNs. The industrial environment can also impact the wireless channel transmission, leading to network reliability problems, even with tightly coupled control and data planes in traditional networks, which obviously also enhances network management cost and complexity. In this paper, we introduce a new software defined network(SDN), and modify this network to propose a framework called the improved software defined wireless sensor network(improved SD-WSN). This proposed framework can address the following issues. 1) For a large scale heterogeneous network, it solves the problem of network management and smooth merging of a WSN into IIo T. 2) The network coverage problem is solved which improves the network reliability. 3) The framework addresses node failure due to various problems, particularly related to energy consumption.Therefore, it is necessary to improve the reliability of wireless sensor networks, by developing certain schemes to reduce energy consumption and the delay time of network nodes under IIo T conditions. Experiments have shown that the improved approach significantly reduces the energy consumption of nodes and the delay time, thus improving the reliability of WSN.

Optimal investment for the defined-contribution pension with stochastic salary under a CEV model

In this paper, we study the optimal investment strategy of defined-contribution pension with the stochastic salary. The investor is allowed to invest in a risk-free asset and a risky asset whose price process follows a constant elasticity of variance model. The stochastic salary follows a stochastic differential equation, whose instantaneous volatility changes with the risky asset price all the time. The HJB equation associated with the optimal investment problem is established, and the explicit solution of the corresponding optimization problem for the CARA utility function is obtained by applying power transform and variable change technique. Finally, we present a numerical analysis.

Analysis of Cardiovascular Risk Factors in Newly Defined Stage 1 Hypertension among Chinese on the Basis of the 2017 ACC/AHA Hypertension Guidelines

In 2017,American College of Cardiology(ACC)/American Heart Association(AHA)et al.jointly released the latest guidelines for adult hypertension,exactly including prevention,diagnosis,assess and treatment,in which blood pressure levels greater than 130/80 mm Hg were defined as hypertension[1].Based on these modified guidelines,the morbidity of hypertension in US increased from 32%to 46%.

Naive Echo-State-Network Based Services Awareness Algorithm of Software Defined Optical Networks

As internet services newly emerge with diversity and complexity, great challenges and demands are presented to the Open Flow controlled software defined optical networks(SDON) to achieve better match between services and SDON. With this aim, this paper proposes a naive Echo-State-Network(Naive-ESN) based services awareness algorithm of the software defined optical network, where the naive ESN model adopts the ring topology structure and generates the probability output result to determine the Qo S policy of SDON. Moreover, the Naive-ESN engine is also designed in controller node of SDON to perform services awareness by obtaining service traffic features from data plan, together with some necessary extension of the Open Flow protocol. Test results show that the proposed approach is able to improved services-oriented supporting ability of SDON.

Dynamic Threshold-Based Approach to Detect Low-Rate DDoS Attacks on Software-Defined Networking Controller

The emergence of a new network architecture,known as Software Defined Networking(SDN),in the last two decades has overcome some drawbacks of traditional networks in terms of performance,scalability,reliability,security,and network management.However,the SDN is vulnerable to security threats that target its controller,such as low-rate Distributed Denial of Service(DDoS)attacks,The low-rate DDoS attack is one of the most prevalent attacks that poses a severe threat to SDN network security because the controller is a vital architecture component.Therefore,there is an urgent need to propose a detection approach for this type of attack with a high detection rate and low false-positive rates.Thus,this paper proposes an approach to detect low-rate DDoS attacks on the SDN controller by adapting a dynamic threshold.The proposed approach has been evaluated using four simulation scenarios covering a combination of low-rate DDoS attacks against the SDN controller involving(i)a single host attack targeting a single victim;(ii)a single host attack targeting multiple victims;(iii)multiple hosts attack targeting a single victim;and(iv)multiple hosts attack targeting multiple victims.The proposed approach’s average detection rates are 96.65%,91.83%,96.17%,and 95.33%for the above scenarios,respectively;and its average false-positive rates are 3.33%,8.17%,3.83%,and 4.67%for similar scenarios,respectively.The comparison between the proposed approach and two existing approaches showed that it outperformed them in both categories.

An Integrated Load Balancing Scheme Based on SDN ASR Algorithm

At present,the flow table of the SDN switch is stored in the costly Ternary Content Addressable Memory(TCAM)cache.Due to the cost problem,the number of flow tables that the SDN switch can store is extremely limited,which is far less than the number of traffic,so it is prone to overflow problem,and leads to network paralysis.That has become a bottleneck in restricting the processing capacity of the data center,and will become a weak point focused by attackers.In this paper,we propose an algorithm for the Alarm Switch Remove(ASR)that fully loads the flow table space in SDN,and further put forward an integrated load balancing scheme in SDN.Finally,we use Mininet to verify that the scheme can ease the SDN switch flow table overflow problem and increase network throughput.

Software defined satellite networks:A survey

In recent years,satellite networks have been proposed as an essential part of next-generation mobile communication systems.Software defined networking techniques are introduced in satellite networks to handle the growing challenges induced by time-varying topology,intermittent inter-satellite link and dramatically increased satellite constellation size.This survey covers the latest progress of software defined satellite networks,including key techniques,existing solutions,challenges,opportunities,and simulation tools.To the best of our knowledge,this paper is the most comprehensive survey that covers the latest progress of software defined satellite networks.An open GitHub repository is further created where the latest papers on this topic will be tracked and updated periodically.Compared with these existing surveys,this survey contributes from three aspects:(1)an up-to-date SDN-oriented review for the latest progress of key techniques and solutions in software defined satellite networks;(2)an inspiring summary of existing challenges,new research opportunities and publicly available simulation tools for follow-up studies;(3)an effort of building a public repository to track new results.

ForSA — A New Software Defined Network Architecture Based on ForCES

In recent years, SDN(Software Defined Network) as a new network architecture has become the hot research point. Meanwhile,the well-known Open Flow-based SDN got a lot of attention. But it can't provide a flexible and effective network resource description method.As an open programmable technology, For CES(Forwarding and Control Element Separation)has also been concerned. However, For CES is confined within a single network node and cannot be applied to the entire network. This paper proposes a new architecture — ForS A(ForC ESbased SDN architecture). The architecture is added a configuration layer based on the traditional SDN architecture, which solves the problem that the northbound interface is not clear between the application layer and the control layer in the SDN architecture. ForS A also implements the compatibility within various forwarding devices in the forwarding layer.

Flicker defined form and RareBit measurements lack in specificity of visual pathways

AIM:To evaluate the different visual pathways represented by the Heidelberg Engineering Perimeter flicker defined form and RareBit(magnocellular and parvocellular respectively)in different age-groups and according to the fatigue.METHODS:Totally 64 eyes of 32 healthy subjects were included in the prospective study.Each participant underwent screening—ophthalmic examination including best-corrected visual acuity,anterior and posterior segment assessment,and visual field examination with Heidelberg Edge Perimetry(HEP)-standard automated perimeter(SAP)24-2.They were observed for 2 y previously to the enrollment.This helped to define that the enrolled patients did not bear the glaucoma-developing potential.During the screening and after two years the HEP had been conducted in the standard protocol 24-2 and RareBit perimetry(RBP)in accordance with the manufacturer’s description.Participants were randomly assigned to the groups:flicker defined form(FDF)-first or RBP-first.This defined from which additional visual field test the participant started.Participants were additionally subdivided to younger and older study groups.The effect of subject variables was explored with Mann-Whitney U-test.Testing for the presence of correlations between parameters was performed using the Spearman Rank Order Correlations and confirmed by the parametric tests.For the influence of additional factors,the Kruskal-Wallis test was performed.RESULTS:The positive correlation between meandeviation(MD)and mean hit rate(MHR)and pattern standard deviation(PSD)and standard deviation of MHR(±MHR)were found in younger study group(P=0.005,r=0.481 and P=0.0074,r=0.465),whereas in the older subgroup no correlation was observed.Additionally,the randomization protocol helped in defining the role of fatigue on the HEP-FDF results.Participant for whom the HEPFDF was performed after RareBit had significantly worse results than those for whom the HEP-FDF was first.In the younger group,the MHR and±MHR depend from age in that group(P<0.05,r=0.43 and r=-0.57 respectively)while no age-dependent differences were found in HEPrelated parameters.On the contrary in the older group the MD and PSD varies with age(P<0.05,r=0.47 and r=-0.44 respectively)while the RBP parameters remained unchanged.The questionnaire showed that participants preferred RareBit over HEP-FDF in terms of a duration time,comfort,understanding of the test procedures,and ocular pain(P<0.05).CONCLUSION:The influence of patient’s fatigue should be considered during HEP-FDF examination.An overlap hypothesis should be reevaluated after determining of other factors that affect HEP-FDF and RareBit results.

A Low-Cost Measurement Framework in Software Defined Networks

Software Defined Network (SDN) makes network management more flexible by separating control plane and data plane, centralized control and being programmable. Although, network measurement still remains in primary stage in SDN, it has become an essential research field in SDN management. In this context, this paper presents a low-cost high-accuracy measurement framework to support various network measurement tasks, such as throughput, delay and packet loss rate. In this framework, we only measure per-flow edge switches (the first and the last switches). In addition, a new adaptive sampling algorithm is proposed to significantly improve measurement accuracy and decrease network overhead. Meanwhile, we consider a low-cost topology discovery approach into our framework instead of topology discovery currently implemented by SDN controller frameworks. In order to improve the accuracy of delay, we also join a time threshold value to adjust the time delay. Furthermore, we consider and analyze the balance between measurement overhead and accuracy in several aspects. Last, we utilize POX controller to implement the proposed measurement framework. The effectiveness of our solution is demonstrated through simulations in Mininet and Matlab.

The User-defined Modeling Method of Power System Components Based on RTDS-CBuilder

This paper puts forward a method to design the user-defined component based on the user-defined modeling environment CBuilder of RTDS simulator. And also develops the user-defined component model with algorithm described by C language, visual graphics appearance, and the component function. And it generates the dynamic link library which has the same execution efficiency as that of the included model of RTDS. This paper takes the IEEE type EXST1 static excitation system as an example to build the user-defined component. The closed-loop tests on the user-defined component and the included one of RTDS are performed to examine the accuracy of the proposed method. By comparison, the test results show that the external characteristics of the user-defined component and the included model of RTDS are basically the same in the initialization process, the step process of the terminal voltage reference value and the case of the large disturbance.

Tunable wavelength filters using polymer long-period waveguide gratings based on metal-cladding directly defined technique

In this work, long-period waveguide grating-based tunable wavelength filters using organic–inorganic grafting poly（methyl methacrylate）（PMMA） materials are designed and fabricated by metal-cladding directly defined technique.The thermal stabilities and optical properties of the organic–inorganic grafting PMMA core materials are analyzed. Structures and performance parameters of the waveguide gratings and self-electrode heaters are designed and simulated. The contrast of the filter is about 15 d B and the resonant wavelength can be tuned by different electric powers applied to the metal-cladding self-electrode heaters. The temperature sensitivity is 3.5 nm/℃ and the switching time is about 1 ms. The technique is very suitable for realizing the optoelectronic integrated wavelength-division-multiplexing systems.