In an era where digital technology is paramount, higher education institutions like the University of Zambia (UNZA) are employing advanced computer networks to enhance their operational capacity and offer cutting-edge...In an era where digital technology is paramount, higher education institutions like the University of Zambia (UNZA) are employing advanced computer networks to enhance their operational capacity and offer cutting-edge services to their academic fraternity. Spanning across the Great East Road campus, UNZA has established one of the most extensive computer networks in Zambia, serving a burgeoning community of over 20,000 active users through a Metropolitan Area Network (MAN). However, as the digital landscape continues to evolve, it is besieged with burgeoning challenges that threaten the very fabric of network integrity—cyber security threats and the imperatives of maintaining high Quality of Service (QoS). In an effort to mitigate these threats and ensure network efficiency, the development of a mobile application to monitor temperatures in the server room was imperative. According to L. Wei, X. Zeng, and T. Shen, the use of wireless sensory networks to monitor the temperature of train switchgear contact points represents a cost-effective solution. The system is based on wireless communication technology and is detailed in their paper, “A wireless solution for train switchgear contact temperature monitoring and alarming system based on wireless communication technology”, published in the International Journal of Communications, Network and System Sciences, vol. 8, no. 4, pp. 79-87, 2015 [1]. Therefore, in this study, a mobile application technology was explored for monitoring of temperatures in the server room in order to aid Cisco device performance. Additionally, this paper also explores the hardening of Cisco device security and QoS which are the cornerstones of this study.展开更多
In recent years, some governments have been working on solutions to transform public administrations and provide high-quality services to users. The United Nations has recommended integrating digital technology into v...In recent years, some governments have been working on solutions to transform public administrations and provide high-quality services to users. The United Nations has recommended integrating digital technology into various aspects of life, including public services. The objective is to offer real-time, high-quality digital services, improve the delivery of public services, enhance their effectiveness and efficiency, while achieving objectives such as transparency, interoperability and citizen satisfaction. However, most governments in developing countries are unable to keep up with this trend. As a result, they often create digital public services that fall short of users’ expectations. This study aims to identify the fundamental factors influencing the quality of service in relation to user satisfaction and to explore the relevance of digital technology in implementing this quality within Cameroon public administrations. To achieve this, we used a qualimetric research method, which included non-directive interviews, questionnaires, and structured observations. The results showed that the public services offered in our study environment did not meet users’ expectations. However, the study identified the fundamental aspects to be considered in providing quality public services connected to user satisfaction, as well as the strengths of digitization in achieving this quality.展开更多
According to Cisco’s Internet Report 2020 white paper,there will be 29.3 billion connected devices worldwide by 2023,up from 18.4 billion in 2018.5G connections will generate nearly three times more traffic than 4G c...According to Cisco’s Internet Report 2020 white paper,there will be 29.3 billion connected devices worldwide by 2023,up from 18.4 billion in 2018.5G connections will generate nearly three times more traffic than 4G connections.While bringing a boom to the network,it also presents unprecedented challenges in terms of flow forwarding decisions.The path assignment mechanism used in traditional traffic schedulingmethods tends to cause local network congestion caused by the concentration of elephant flows,resulting in unbalanced network load and degraded quality of service.Using the centralized control of software-defined networks,this study proposes a data center traffic scheduling strategy for minimization congestion and quality of service guaranteeing(MCQG).The ideal transmission path is selected for data flows while considering the network congestion rate and quality of service.Different traffic scheduling strategies are used according to the characteristics of different service types in data centers.Reroute scheduling for elephant flows that tend to cause local congestion.The path evaluation function is formed by the maximum link utilization on the path,the number of elephant flows and the time delay,and the fast merit-seeking capability of the sparrow search algorithm is used to find the path with the lowest actual link overhead as the rerouting path for the elephant flows.It is used to reduce the possibility of local network congestion occurrence.Equal cost multi-path(ECMP)protocols with faster response time are used to schedulemouse flows with shorter duration.Used to guarantee the quality of service of the network.To achieve isolated transmission of various types of data streams.The experimental results show that the proposed strategy has higher throughput,better network load balancing,and better robustness compared to ECMP under different traffic models.In addition,because it can fully utilize the resources in the network,MCQG also outperforms another traffic scheduling strategy that does rerouting for elephant flows(namely Hedera).Compared withECMPandHedera,MCQGimproves average throughput by 11.73%and 4.29%,and normalized total throughput by 6.74%and 2.64%,respectively;MCQG improves link utilization by 23.25%and 15.07%;in addition,the average round-trip delay and packet loss rate fluctuate significantly less than the two compared strategies.展开更多
On-demand availability and resource elasticity features of Cloud computing have attracted the focus of various research domains.Mobile cloud computing is one of these domains where complex computation tasks are offloa...On-demand availability and resource elasticity features of Cloud computing have attracted the focus of various research domains.Mobile cloud computing is one of these domains where complex computation tasks are offloaded to the cloud resources to augment mobile devices’cognitive capacity.However,the flexible provisioning of cloud resources is hindered by uncertain offloading workloads and significant setup time of cloud virtual machines(VMs).Furthermore,any delays at the cloud end would further aggravate the miseries of real-time tasks.To resolve these issues,this paper proposes an auto-scaling framework(ACF)that strives to maintain the quality of service(QoS)for the end users as per the service level agreement(SLA)negotiated assurance level for service availability.In addition,it also provides an innovative solution for dealing with the VM startup overheads without truncating the running tasks.Unlike the waiting cost and service cost tradeoff-based systems or threshold-rule-based systems,it does not require strict tuning in the waiting costs or in the threshold rules for enhancing the QoS.We explored the design space of the ACF system with the CloudSim simulator.The extensive sets of experiments demonstrate the effectiveness of the ACF system in terms of good reduction in energy dissipation at the mobile devices and improvement in the QoS.At the same time,the proposed ACF system also reduces the monetary costs of the service providers.展开更多
Modernization of armies is a constant process and is driven by intuitive fact that those who do not modernize will become extinct. In last five decades, the development of modern armies has taken place around Colonel ...Modernization of armies is a constant process and is driven by intuitive fact that those who do not modernize will become extinct. In last five decades, the development of modern armies has taken place around Colonel John Boyd’s theory of OODA loop that deals with information superiority. Building a robust, mobile and capable network that could provide for novel appliances and information superiority is the main challenge which modernizers are facing. Network, suitable for future combat operations, and able to transport a vast amount of information on a battlefield, is expensive to build. Every mistake in design and the need to correct those mistakes could halt development in an army for years. Therefore, system dependability analysis during system design phase is needed. In this report, the concept of a future Battle Network System is described. The Report evaluates operational environment of BNS and possible failure reasons of the service, and illustrates the change in BNS Quality of Service due to probable transport layer errors. This paper describes the method of testing the concept of proposed network systems on the drawing board, and emphasizes design points for a new system. Nevertheless, the proposed method is by no means conclusive. Rather, it describes an engineering approach to define the main problems while creating MANET-based networking systems.展开更多
Small cells have been regarded as an appealing technique to boost resource reuse ratio. On the other hand, their large-scale and self-organised tendency would complicate the interference environment of mobile networks...Small cells have been regarded as an appealing technique to boost resource reuse ratio. On the other hand, their large-scale and self-organised tendency would complicate the interference environment of mobile networks. Meanwhile, traffic class is booming in recent years, which leads to higher demand for net- work designers on Quality of Service (QoS) provision, and therefore users' diverse re- quirements may not be guaranteed in sucff'an interference limited scenario. To maximise the number of users with QoS demands as well as resource reuse ratio, we formulate the resource allocation problem into a multi-objective l0 norm form. It is shown to be NP hard, and an iterative method is employed to approach the optimal solution. Because of its limit of being not adaptive to large-scale networks, we also design a heuristic method based on chordal graph, which, however, could result in per- formance loss when the size of networks is small. Finally, by combining these two meth- ods, we devise a hybrid algorithm such that the allocation performs both efficiently and effectively. Simulation results illustrate the performance of our proposed methods in terms of outage probability and resource reuse ratio.展开更多
Cloud computing is providing IT services to its customer based on Service level agreements(SLAs).It is important for cloud service providers to provide reliable Quality of service(QoS)and to maintain SLAs accountabili...Cloud computing is providing IT services to its customer based on Service level agreements(SLAs).It is important for cloud service providers to provide reliable Quality of service(QoS)and to maintain SLAs accountability.Cloud service providers need to predict possible service violations before the emergence of an issue to perform remedial actions for it.Cloud users’major concerns;the factors for service reliability are based on response time,accessibility,availability,and speed.In this paper,we,therefore,experiment with the parallel mutant-Particle swarm optimization(PSO)for the detection and predictions of QoS violations in terms of response time,speed,accessibility,and availability.This paper also compares Simple-PSO and Parallel MutantPSO.In simulation results,it is observed that the proposed Parallel MutantPSO solution for cloud QoS violation prediction achieves 94%accuracy which is many accurate results and is computationally the fastest technique in comparison of conventional PSO technique.展开更多
This paper investigates the routing among autonomous systems (ASs) with quality of service (QoS) requirements. To avoid the intractability of the problem, abstract QoS capability must be informed among ASs, because th...This paper investigates the routing among autonomous systems (ASs) with quality of service (QoS) requirements. To avoid the intractability of the problem, abstract QoS capability must be informed among ASs, because the routhing which constrained QoS has been proved to be nondeterministic polynomial-time (NP) hard even inside an AS. This paper employs the modified Dijkstra algorithm to compute the maximum bottleneck bandwidth inside an AS. This approach lays a basis for the AS-level switching capability on which interdomain advertisement can be performed. Furthermore, the paper models the aggregated traffic in backbone network with fractional Brownian motion (FBM), and by integrating along the time axis in short intervals, a good estimation of the distribution of queue length in the next short intervals can be obtained. The proposed advertisement mechanism can be easily implemented with the current interdomain routing protocols. Numerical study indicates that the presented scheme is effective and feasible.展开更多
An assessment method for the quality of service (QoS) of virtual knowledge communities (VKC) is proposed based on fuzzy theory and analytic hierarchy process (AHP). The QoS is evaluated in terms of Website desig...An assessment method for the quality of service (QoS) of virtual knowledge communities (VKC) is proposed based on fuzzy theory and analytic hierarchy process (AHP). The QoS is evaluated in terms of Website design, reliability, responsiveness, trust, personalization, and information quality. The cognitive QoS and the QoS evaluated by assessors are compared to analyze which QoS of the VKC should be improved urgently and which indicators keep leading positions, and to assist administrators of the VKC on measuring and understanding current status and implementation effect of the QoS.展开更多
This paper empirically evaluates container terminal service attributes. The methodology proposed focuses on statistical control, Based on the concept of service segmentation, the authors employed control charts to cla...This paper empirically evaluates container terminal service attributes. The methodology proposed focuses on statistical control, Based on the concept of service segmentation, the authors employed control charts to classify container terminal services. The purpose of control charts is to allow simple detection of events that are indicative of actual process change. This simple decision can be difficult where the process characteristic is continuously varying, the control chart provides statistically objective criteria of change. When change is detected and considered good its cause should be identified and possibly become the new way of working, where the change is bad then its cause should be identified and eliminated. Both theoretical and practical implications of the research findings are discussed in this paper.展开更多
To guarantee the Quality of Service (QoS) is one of the key objectives of the next generation network.Based on the introduction of the Next Generation Network(NGN) and the definition of QoS,various aspects of QoS are ...To guarantee the Quality of Service (QoS) is one of the key objectives of the next generation network.Based on the introduction of the Next Generation Network(NGN) and the definition of QoS,various aspects of QoS are analyzed in this article,with emphasis on different approaches and business models.It is noted that QoS concerns the parametric network performance parameters and the application “satisfaction” level.展开更多
Mobility and resource-limitedness pose challenging issues to service configuration for quality of service (QoS) management in ubiquitous computing environments. Previous configuration approaches, such as static resour...Mobility and resource-limitedness pose challenging issues to service configuration for quality of service (QoS) management in ubiquitous computing environments. Previous configuration approaches, such as static resource reservation, dynamic resource allocation and single service composition are not valid in the environments. In this study, we present an adaptive service configuration approach. Firstly, we reduce the dynamic configuration process to a control model which aims to achieve the variation of critical QoS on minimal level with less resource cost. Secondly, to deal with different QoS variations, we design two configuration strategies—service chain reconfiguration and QoS parameter adjustment—and implement them based on fuzzy logic control theory. Finally, a configuration algorithm is developed to flexibly employ the two configuration strategies in tune with the error of critical QoS in configuration process. The results of simulation experiments suggest that our approach outper- forms existing configuration approaches in both QoS improvement and resource utilization.展开更多
Active queue management(AQM) is essentially a router buffer management strategy supporting TCP congestion control.Since existing AQM schemes exhibit poor performance and even instability in time delay uncertain networ...Active queue management(AQM) is essentially a router buffer management strategy supporting TCP congestion control.Since existing AQM schemes exhibit poor performance and even instability in time delay uncertain networks,a robust buffer management(RBM) mechanism is proposed to guarantee the quality of service(QoS).RBM consists of a Smith predictor and two independent controllers.The Smith predictor is used to compensate for the round trip time(RTT) delay and to restrain its negative influence on network performance.The main feedback controller and the disturbance rejection controller are designed as proportional-integral (PI) controller and proportional(P) controller by internal model control(IMC) and frequency-domain analysis respectively.By simulation experiments in Netwrok-Simulator-2(NS2),it is demonstrated that RBM can effectively manage the buffer occupation around the target value against time delay and system disturbance. Compared with delay compensation-AQM algorithm(DC-AQM),proportional-integral-derivative(PID) algorithm and random exponential marking(REM) algorithm,the RBM scheme exhibits the superiority in terms of stability, responsiveness and robustness.展开更多
The development of IP-based Internet of Things(IoT)networks would facilitate more effective end-to-end IP network architectures,but it remains a challenge.Network routing needs to be effectively addressed in the IoT e...The development of IP-based Internet of Things(IoT)networks would facilitate more effective end-to-end IP network architectures,but it remains a challenge.Network routing needs to be effectively addressed in the IoT environments of scarce computational and energy resources.Accordingly,the Internet Engineering Task Force(IETF)has specified the IPv6 Routing Protocol for Low Power and Lossy Network(RPL)to provide a bespoke IPv6-based routing framework for IoT networks.However,RPL comes with no Quality of Service(QoS)support which is an essential requirement for many IoT applications.The network research community has introduced a number of research proposals enhancing RPL with different QoS solutions.This paper presents a review of these proposed solutions and aims to establish a firm understanding of recent QoS developments for RPL and possible areas for future IoT routing research.The focus is on comprehending the protocol and networking properties that can affect QoS performance in RPL networks.Consideration is also given to different objective functions developed for addressing varying QoS aspects such as throughput,delay,and packet loss.RPL is also extended in a number of QoS solutions following different approaches at the MAC,network,and application layers.However,there is still a need for further developments to address effective QoS support,particularly for dynamic RPL networks.展开更多
Objective To enhance the quality of medical service for Chinese patients through research of service quality from Chinese medical personnel. Methods Serv Qual scale was used for infection medical staffs randomly by sa...Objective To enhance the quality of medical service for Chinese patients through research of service quality from Chinese medical personnel. Methods Serv Qual scale was used for infection medical staffs randomly by sampling questionnaire in Beijing, Shanghai, Chengdu, Chongqing, Guangzhou and Nanning. The data collected were entered and analyzed using SPSS 20.0. Statistical methods included frequency, factor analysis, reliability analysis, correlation analysis, independent samples t test, one-way analyses of variance, simultaneous regression analysis and structural equation model analysis. Results The Kaiser-Meyer-Olkin value for the factor analysis of the scale was 0.970. The Cronbach's α for the reliability analysis was 0.975. The Pearson correlation coefficients were 0.624-0.874 and statistically significant. Undergraduates felt good, Ph D students felt bad; the doctors felt bad; managers felt good. Standard 5 dimensions of the regression coefficients were positive, including empathy(β = 0.288), reliability(β = 0.241) impacting on perceived service quality mostly. The control ability and stability of the standard error of perceived service quality directly effected value were 0.646 and 0.382, respectively. Conclusions Medical staffs of infectious disease department have poor perception of service quality. Hospitals should improve awareness and of clinicians and deepen the reform of the medical care system.展开更多
Based on service-oriented architecture(SOA),a Bellman-dynamic-programming-based approach of service recovery decision-making is proposed to make valid recovery decisions.Both the attribute and the process of service...Based on service-oriented architecture(SOA),a Bellman-dynamic-programming-based approach of service recovery decision-making is proposed to make valid recovery decisions.Both the attribute and the process of services in the controllable distributed information system are analyzed as the preparatory work.Using the idea of service composition as a reference,the approach translates the recovery decision-making into a planning problem regarding artificial intelligence (AI) through two steps.The first is the self-organization based on a logical view of the network,and the second is the definition of evaluation standards.Applying Bellman dynamic programming to solve the planning problem,the approach offers timely emergency response and optimal recovery source selection,meeting multiple QoS (quality of service)requirements.Experimental results demonstrate the rationality and optimality of the approach,and the theoretical analysis of its computational complexity and the comparison with conventional methods exhibit its high efficiency.展开更多
Cloud computing can be realized by service interoperation and its essence is to provide cloud services through network. The development of effective methods to assure the trustworthiness of service interoperation in c...Cloud computing can be realized by service interoperation and its essence is to provide cloud services through network. The development of effective methods to assure the trustworthiness of service interoperation in cloud environment is a very important problem. The essence of cloud security is trust and trust management. Combining quality of service (QoS) with trust model, this paper constructs a QoS-aware and quantitative trust-model that consists of initial trust value, direct trust value, and recommendatory trust value of service, making the provision, discovery, and aggregation of cloud services trustworthy. Hence, it can assure trustworthiness of service interoperation between users and services or among services in cloud environment. At the same time, based on this model, service discovery method based on QoS-aware and quantitative trust-model (TQoS-WSD) is proposed, which makes a solid trust relationship among service requestor, service provider and service recommender, and users can find trustworthy service whose total evaluation value is higher. Corapared to QoS-based service discovery (QoS-WSD) method, it is proved by the experiment for TQoS-WSD method that more accurate result of service discovery will be achieved by service requestor, while reasonable time cost is increased. Meanwhile, TQoS-WSD method strongly resists the effect of service discovery by untrustworthy QoS values and improves service invocation success-rate and thus assures trustworthiness of services interoperation.展开更多
With the development of the service-oriented computing(SOC),web service has an important and popular solution for the design of the application system to various enterprises.Nowadays,the numerous web services are prov...With the development of the service-oriented computing(SOC),web service has an important and popular solution for the design of the application system to various enterprises.Nowadays,the numerous web services are provided by the service providers on the network,it becomes difficult for users to select the best reliable one from a large number of services with the same function.So it is necessary to design feasible selection strategies to provide users with the reliable services.Most existing methods attempt to select services according to accurate predictions for the quality of service(QoS)values.However,because the network and user needs are dynamic,it is almost impossible to accurately predict the QoS values.Furthermore,accurate prediction is generally time-consuming.This paper proposes a service decision tree based post-pruning prediction approach.This paper first defines the five reliability levels for measuring the reliability of services.By analyzing the quality data of service from the network,the proposed method can generate the training set and convert them into the service decision tree model.Using the generated model and the given predicted services,the proposed method classifies the service to the corresponding reliability level after discretizing the continuous attribute of service.Moreover,this paper applies the post-pruning strategy to optimize the generated model for avoiding the over-fitting.Experimental results show that the proposed method is effective in predicting the service reliability.展开更多
Quality of experience(Qo E), which is very critical for the experience of users in wireless networks, has been extensively studied. However, due to different human perceptions, quantifying the effective capacity of wi...Quality of experience(Qo E), which is very critical for the experience of users in wireless networks, has been extensively studied. However, due to different human perceptions, quantifying the effective capacity of wireless network subject to diverse Qo E is very difficult, which leads to many new challenges regarding Qo E guarantees in wireless networks. In this paper, we formulate the Qo E guarantees model for cellular wireless networks. Based on the model, we convert the effective capacity maximization problem into the equivalent convex optimization problem. Then, we develop the optimal Qo E-driven power allocation scheme, which can maximize the effective capacity. The obtained simulation results verified our proposed power allocation scheme, showing that the effective capacity can be significantly increased compared with that of traditional Qo E guarantees based schemes.展开更多
文摘In an era where digital technology is paramount, higher education institutions like the University of Zambia (UNZA) are employing advanced computer networks to enhance their operational capacity and offer cutting-edge services to their academic fraternity. Spanning across the Great East Road campus, UNZA has established one of the most extensive computer networks in Zambia, serving a burgeoning community of over 20,000 active users through a Metropolitan Area Network (MAN). However, as the digital landscape continues to evolve, it is besieged with burgeoning challenges that threaten the very fabric of network integrity—cyber security threats and the imperatives of maintaining high Quality of Service (QoS). In an effort to mitigate these threats and ensure network efficiency, the development of a mobile application to monitor temperatures in the server room was imperative. According to L. Wei, X. Zeng, and T. Shen, the use of wireless sensory networks to monitor the temperature of train switchgear contact points represents a cost-effective solution. The system is based on wireless communication technology and is detailed in their paper, “A wireless solution for train switchgear contact temperature monitoring and alarming system based on wireless communication technology”, published in the International Journal of Communications, Network and System Sciences, vol. 8, no. 4, pp. 79-87, 2015 [1]. Therefore, in this study, a mobile application technology was explored for monitoring of temperatures in the server room in order to aid Cisco device performance. Additionally, this paper also explores the hardening of Cisco device security and QoS which are the cornerstones of this study.
文摘In recent years, some governments have been working on solutions to transform public administrations and provide high-quality services to users. The United Nations has recommended integrating digital technology into various aspects of life, including public services. The objective is to offer real-time, high-quality digital services, improve the delivery of public services, enhance their effectiveness and efficiency, while achieving objectives such as transparency, interoperability and citizen satisfaction. However, most governments in developing countries are unable to keep up with this trend. As a result, they often create digital public services that fall short of users’ expectations. This study aims to identify the fundamental factors influencing the quality of service in relation to user satisfaction and to explore the relevance of digital technology in implementing this quality within Cameroon public administrations. To achieve this, we used a qualimetric research method, which included non-directive interviews, questionnaires, and structured observations. The results showed that the public services offered in our study environment did not meet users’ expectations. However, the study identified the fundamental aspects to be considered in providing quality public services connected to user satisfaction, as well as the strengths of digitization in achieving this quality.
基金This work is funded by the National Natural Science Foundation of China under Grant No.61772180the Key R&D plan of Hubei Province(2020BHB004,2020BAB012).
文摘According to Cisco’s Internet Report 2020 white paper,there will be 29.3 billion connected devices worldwide by 2023,up from 18.4 billion in 2018.5G connections will generate nearly three times more traffic than 4G connections.While bringing a boom to the network,it also presents unprecedented challenges in terms of flow forwarding decisions.The path assignment mechanism used in traditional traffic schedulingmethods tends to cause local network congestion caused by the concentration of elephant flows,resulting in unbalanced network load and degraded quality of service.Using the centralized control of software-defined networks,this study proposes a data center traffic scheduling strategy for minimization congestion and quality of service guaranteeing(MCQG).The ideal transmission path is selected for data flows while considering the network congestion rate and quality of service.Different traffic scheduling strategies are used according to the characteristics of different service types in data centers.Reroute scheduling for elephant flows that tend to cause local congestion.The path evaluation function is formed by the maximum link utilization on the path,the number of elephant flows and the time delay,and the fast merit-seeking capability of the sparrow search algorithm is used to find the path with the lowest actual link overhead as the rerouting path for the elephant flows.It is used to reduce the possibility of local network congestion occurrence.Equal cost multi-path(ECMP)protocols with faster response time are used to schedulemouse flows with shorter duration.Used to guarantee the quality of service of the network.To achieve isolated transmission of various types of data streams.The experimental results show that the proposed strategy has higher throughput,better network load balancing,and better robustness compared to ECMP under different traffic models.In addition,because it can fully utilize the resources in the network,MCQG also outperforms another traffic scheduling strategy that does rerouting for elephant flows(namely Hedera).Compared withECMPandHedera,MCQGimproves average throughput by 11.73%and 4.29%,and normalized total throughput by 6.74%and 2.64%,respectively;MCQG improves link utilization by 23.25%and 15.07%;in addition,the average round-trip delay and packet loss rate fluctuate significantly less than the two compared strategies.
基金This research work is funded by TEQIP-III under Assistantship Head:1.3.2.2 in PFMS dated 29.06.2021.
文摘On-demand availability and resource elasticity features of Cloud computing have attracted the focus of various research domains.Mobile cloud computing is one of these domains where complex computation tasks are offloaded to the cloud resources to augment mobile devices’cognitive capacity.However,the flexible provisioning of cloud resources is hindered by uncertain offloading workloads and significant setup time of cloud virtual machines(VMs).Furthermore,any delays at the cloud end would further aggravate the miseries of real-time tasks.To resolve these issues,this paper proposes an auto-scaling framework(ACF)that strives to maintain the quality of service(QoS)for the end users as per the service level agreement(SLA)negotiated assurance level for service availability.In addition,it also provides an innovative solution for dealing with the VM startup overheads without truncating the running tasks.Unlike the waiting cost and service cost tradeoff-based systems or threshold-rule-based systems,it does not require strict tuning in the waiting costs or in the threshold rules for enhancing the QoS.We explored the design space of the ACF system with the CloudSim simulator.The extensive sets of experiments demonstrate the effectiveness of the ACF system in terms of good reduction in energy dissipation at the mobile devices and improvement in the QoS.At the same time,the proposed ACF system also reduces the monetary costs of the service providers.
文摘Modernization of armies is a constant process and is driven by intuitive fact that those who do not modernize will become extinct. In last five decades, the development of modern armies has taken place around Colonel John Boyd’s theory of OODA loop that deals with information superiority. Building a robust, mobile and capable network that could provide for novel appliances and information superiority is the main challenge which modernizers are facing. Network, suitable for future combat operations, and able to transport a vast amount of information on a battlefield, is expensive to build. Every mistake in design and the need to correct those mistakes could halt development in an army for years. Therefore, system dependability analysis during system design phase is needed. In this report, the concept of a future Battle Network System is described. The Report evaluates operational environment of BNS and possible failure reasons of the service, and illustrates the change in BNS Quality of Service due to probable transport layer errors. This paper describes the method of testing the concept of proposed network systems on the drawing board, and emphasizes design points for a new system. Nevertheless, the proposed method is by no means conclusive. Rather, it describes an engineering approach to define the main problems while creating MANET-based networking systems.
基金ACKNOWLEDGEMENT First, thanks for the invitation from the organ- isers of IEEE/CIC ICCC 2013 held in Xi'an, China. This work was supported by the Na- tional Natural Science Foundation of China under Grants No. 60972047, No. 61231008 the National Science and Technology Major Project under Grams No. 2011ZX03005-004, No. 2011ZX03004-003, No. 2011ZX03005- 003-03, No. 2013ZX03004007-003+4 种基金 the Shannxi 13115 Project under Grant No. 2010ZDKG-26 the National Basic Research Program of China (973 Program) under Grant No. 2009CB320404 the Program for Changjiang Scholars and Inn- ovative Research Team in University under Gr- ant No. IRT0852 the 111 Project under Grant No. B08038 and the State Key Laboratory Fou- ndation under Grants No. ISN1002005, No. ISN090305.
文摘Small cells have been regarded as an appealing technique to boost resource reuse ratio. On the other hand, their large-scale and self-organised tendency would complicate the interference environment of mobile networks. Meanwhile, traffic class is booming in recent years, which leads to higher demand for net- work designers on Quality of Service (QoS) provision, and therefore users' diverse re- quirements may not be guaranteed in sucff'an interference limited scenario. To maximise the number of users with QoS demands as well as resource reuse ratio, we formulate the resource allocation problem into a multi-objective l0 norm form. It is shown to be NP hard, and an iterative method is employed to approach the optimal solution. Because of its limit of being not adaptive to large-scale networks, we also design a heuristic method based on chordal graph, which, however, could result in per- formance loss when the size of networks is small. Finally, by combining these two meth- ods, we devise a hybrid algorithm such that the allocation performs both efficiently and effectively. Simulation results illustrate the performance of our proposed methods in terms of outage probability and resource reuse ratio.
文摘Cloud computing is providing IT services to its customer based on Service level agreements(SLAs).It is important for cloud service providers to provide reliable Quality of service(QoS)and to maintain SLAs accountability.Cloud service providers need to predict possible service violations before the emergence of an issue to perform remedial actions for it.Cloud users’major concerns;the factors for service reliability are based on response time,accessibility,availability,and speed.In this paper,we,therefore,experiment with the parallel mutant-Particle swarm optimization(PSO)for the detection and predictions of QoS violations in terms of response time,speed,accessibility,and availability.This paper also compares Simple-PSO and Parallel MutantPSO.In simulation results,it is observed that the proposed Parallel MutantPSO solution for cloud QoS violation prediction achieves 94%accuracy which is many accurate results and is computationally the fastest technique in comparison of conventional PSO technique.
文摘This paper investigates the routing among autonomous systems (ASs) with quality of service (QoS) requirements. To avoid the intractability of the problem, abstract QoS capability must be informed among ASs, because the routhing which constrained QoS has been proved to be nondeterministic polynomial-time (NP) hard even inside an AS. This paper employs the modified Dijkstra algorithm to compute the maximum bottleneck bandwidth inside an AS. This approach lays a basis for the AS-level switching capability on which interdomain advertisement can be performed. Furthermore, the paper models the aggregated traffic in backbone network with fractional Brownian motion (FBM), and by integrating along the time axis in short intervals, a good estimation of the distribution of queue length in the next short intervals can be obtained. The proposed advertisement mechanism can be easily implemented with the current interdomain routing protocols. Numerical study indicates that the presented scheme is effective and feasible.
文摘An assessment method for the quality of service (QoS) of virtual knowledge communities (VKC) is proposed based on fuzzy theory and analytic hierarchy process (AHP). The QoS is evaluated in terms of Website design, reliability, responsiveness, trust, personalization, and information quality. The cognitive QoS and the QoS evaluated by assessors are compared to analyze which QoS of the VKC should be improved urgently and which indicators keep leading positions, and to assist administrators of the VKC on measuring and understanding current status and implementation effect of the QoS.
文摘This paper empirically evaluates container terminal service attributes. The methodology proposed focuses on statistical control, Based on the concept of service segmentation, the authors employed control charts to classify container terminal services. The purpose of control charts is to allow simple detection of events that are indicative of actual process change. This simple decision can be difficult where the process characteristic is continuously varying, the control chart provides statistically objective criteria of change. When change is detected and considered good its cause should be identified and possibly become the new way of working, where the change is bad then its cause should be identified and eliminated. Both theoretical and practical implications of the research findings are discussed in this paper.
文摘To guarantee the Quality of Service (QoS) is one of the key objectives of the next generation network.Based on the introduction of the Next Generation Network(NGN) and the definition of QoS,various aspects of QoS are analyzed in this article,with emphasis on different approaches and business models.It is noted that QoS concerns the parametric network performance parameters and the application “satisfaction” level.
基金Project (No. 05SN07114) supported by the International Cooperation Project of the Shanghai Science and Technology Commission of China and the National Research Council of Canada
文摘Mobility and resource-limitedness pose challenging issues to service configuration for quality of service (QoS) management in ubiquitous computing environments. Previous configuration approaches, such as static resource reservation, dynamic resource allocation and single service composition are not valid in the environments. In this study, we present an adaptive service configuration approach. Firstly, we reduce the dynamic configuration process to a control model which aims to achieve the variation of critical QoS on minimal level with less resource cost. Secondly, to deal with different QoS variations, we design two configuration strategies—service chain reconfiguration and QoS parameter adjustment—and implement them based on fuzzy logic control theory. Finally, a configuration algorithm is developed to flexibly employ the two configuration strategies in tune with the error of critical QoS in configuration process. The results of simulation experiments suggest that our approach outper- forms existing configuration approaches in both QoS improvement and resource utilization.
基金the National Natural Science Foundation of China(No.60574081)
文摘Active queue management(AQM) is essentially a router buffer management strategy supporting TCP congestion control.Since existing AQM schemes exhibit poor performance and even instability in time delay uncertain networks,a robust buffer management(RBM) mechanism is proposed to guarantee the quality of service(QoS).RBM consists of a Smith predictor and two independent controllers.The Smith predictor is used to compensate for the round trip time(RTT) delay and to restrain its negative influence on network performance.The main feedback controller and the disturbance rejection controller are designed as proportional-integral (PI) controller and proportional(P) controller by internal model control(IMC) and frequency-domain analysis respectively.By simulation experiments in Netwrok-Simulator-2(NS2),it is demonstrated that RBM can effectively manage the buffer occupation around the target value against time delay and system disturbance. Compared with delay compensation-AQM algorithm(DC-AQM),proportional-integral-derivative(PID) algorithm and random exponential marking(REM) algorithm,the RBM scheme exhibits the superiority in terms of stability, responsiveness and robustness.
文摘The development of IP-based Internet of Things(IoT)networks would facilitate more effective end-to-end IP network architectures,but it remains a challenge.Network routing needs to be effectively addressed in the IoT environments of scarce computational and energy resources.Accordingly,the Internet Engineering Task Force(IETF)has specified the IPv6 Routing Protocol for Low Power and Lossy Network(RPL)to provide a bespoke IPv6-based routing framework for IoT networks.However,RPL comes with no Quality of Service(QoS)support which is an essential requirement for many IoT applications.The network research community has introduced a number of research proposals enhancing RPL with different QoS solutions.This paper presents a review of these proposed solutions and aims to establish a firm understanding of recent QoS developments for RPL and possible areas for future IoT routing research.The focus is on comprehending the protocol and networking properties that can affect QoS performance in RPL networks.Consideration is also given to different objective functions developed for addressing varying QoS aspects such as throughput,delay,and packet loss.RPL is also extended in a number of QoS solutions following different approaches at the MAC,network,and application layers.However,there is still a need for further developments to address effective QoS support,particularly for dynamic RPL networks.
基金supported by the year 2014 Key Research Project of the Party of the Education and Health of Shanghai(NO:201420)Scientific Research in Hospital Construction Project of Chinese Medical Doctor Assoclation
文摘Objective To enhance the quality of medical service for Chinese patients through research of service quality from Chinese medical personnel. Methods Serv Qual scale was used for infection medical staffs randomly by sampling questionnaire in Beijing, Shanghai, Chengdu, Chongqing, Guangzhou and Nanning. The data collected were entered and analyzed using SPSS 20.0. Statistical methods included frequency, factor analysis, reliability analysis, correlation analysis, independent samples t test, one-way analyses of variance, simultaneous regression analysis and structural equation model analysis. Results The Kaiser-Meyer-Olkin value for the factor analysis of the scale was 0.970. The Cronbach's α for the reliability analysis was 0.975. The Pearson correlation coefficients were 0.624-0.874 and statistically significant. Undergraduates felt good, Ph D students felt bad; the doctors felt bad; managers felt good. Standard 5 dimensions of the regression coefficients were positive, including empathy(β = 0.288), reliability(β = 0.241) impacting on perceived service quality mostly. The control ability and stability of the standard error of perceived service quality directly effected value were 0.646 and 0.382, respectively. Conclusions Medical staffs of infectious disease department have poor perception of service quality. Hospitals should improve awareness and of clinicians and deepen the reform of the medical care system.
文摘Based on service-oriented architecture(SOA),a Bellman-dynamic-programming-based approach of service recovery decision-making is proposed to make valid recovery decisions.Both the attribute and the process of services in the controllable distributed information system are analyzed as the preparatory work.Using the idea of service composition as a reference,the approach translates the recovery decision-making into a planning problem regarding artificial intelligence (AI) through two steps.The first is the self-organization based on a logical view of the network,and the second is the definition of evaluation standards.Applying Bellman dynamic programming to solve the planning problem,the approach offers timely emergency response and optimal recovery source selection,meeting multiple QoS (quality of service)requirements.Experimental results demonstrate the rationality and optimality of the approach,and the theoretical analysis of its computational complexity and the comparison with conventional methods exhibit its high efficiency.
基金supported by National Basic Research Program of China (973 Program) (No. 2007CB310801)National Natural Science Foundation of China (No. 60873083, No. 60803025, No. 60970017, No. 60903034, No. 60873225)+3 种基金Natural Science Foundation of Hubei Province for Distinguished Young Scholars (No. 2008CDB351)Natural Science Foundation of Hubei Province (No. 2008ABA358, No. 2008ABA379)Research Fund for the Doctoral Program of Higher Education of China (No. 20070486065)Open Foundation of State Key Laboratory of Software Engineering (No. SKLSE20080718)
文摘Cloud computing can be realized by service interoperation and its essence is to provide cloud services through network. The development of effective methods to assure the trustworthiness of service interoperation in cloud environment is a very important problem. The essence of cloud security is trust and trust management. Combining quality of service (QoS) with trust model, this paper constructs a QoS-aware and quantitative trust-model that consists of initial trust value, direct trust value, and recommendatory trust value of service, making the provision, discovery, and aggregation of cloud services trustworthy. Hence, it can assure trustworthiness of service interoperation between users and services or among services in cloud environment. At the same time, based on this model, service discovery method based on QoS-aware and quantitative trust-model (TQoS-WSD) is proposed, which makes a solid trust relationship among service requestor, service provider and service recommender, and users can find trustworthy service whose total evaluation value is higher. Corapared to QoS-based service discovery (QoS-WSD) method, it is proved by the experiment for TQoS-WSD method that more accurate result of service discovery will be achieved by service requestor, while reasonable time cost is increased. Meanwhile, TQoS-WSD method strongly resists the effect of service discovery by untrustworthy QoS values and improves service invocation success-rate and thus assures trustworthiness of services interoperation.
基金This paper is partially supported by the National Natural Science Foundation of China under Grant No.61972053 and No.61603054by the Scientific Research Foundation of Liaoning Education Department under Grant No.LQ2019016,No.LJ2019015by the Natural Science Foundation of Liaoning Province,China under Grant No.2019-ZD-0505.
文摘With the development of the service-oriented computing(SOC),web service has an important and popular solution for the design of the application system to various enterprises.Nowadays,the numerous web services are provided by the service providers on the network,it becomes difficult for users to select the best reliable one from a large number of services with the same function.So it is necessary to design feasible selection strategies to provide users with the reliable services.Most existing methods attempt to select services according to accurate predictions for the quality of service(QoS)values.However,because the network and user needs are dynamic,it is almost impossible to accurately predict the QoS values.Furthermore,accurate prediction is generally time-consuming.This paper proposes a service decision tree based post-pruning prediction approach.This paper first defines the five reliability levels for measuring the reliability of services.By analyzing the quality data of service from the network,the proposed method can generate the training set and convert them into the service decision tree model.Using the generated model and the given predicted services,the proposed method classifies the service to the corresponding reliability level after discretizing the continuous attribute of service.Moreover,this paper applies the post-pruning strategy to optimize the generated model for avoiding the over-fitting.Experimental results show that the proposed method is effective in predicting the service reliability.
基金supported by National Natural Science Foundation of China(61305134)Specialized Research Fund for the Doctoral Program of Higher Education(20133219120035)
基金supported in part by the National Natural Science Foundation of China(Nos.61771368 and 61671347)Young Elite Scientists Sponsorship Program by CAST(2016QNRC001)
文摘Quality of experience(Qo E), which is very critical for the experience of users in wireless networks, has been extensively studied. However, due to different human perceptions, quantifying the effective capacity of wireless network subject to diverse Qo E is very difficult, which leads to many new challenges regarding Qo E guarantees in wireless networks. In this paper, we formulate the Qo E guarantees model for cellular wireless networks. Based on the model, we convert the effective capacity maximization problem into the equivalent convex optimization problem. Then, we develop the optimal Qo E-driven power allocation scheme, which can maximize the effective capacity. The obtained simulation results verified our proposed power allocation scheme, showing that the effective capacity can be significantly increased compared with that of traditional Qo E guarantees based schemes.