Quality Of Service Specification Research Articles

A Review on Modern Spectrum Sensing and Assignment Techniques in CRN

Cognitive radio (CR) is ascending as an advanced technology with the aim of utilizing the unused spectrum bands in an opportunistic and dynamic way. Fixed spectrum allocation done by government based agencies leads to underutilization of resources. The segments of spectrum bands that are unused, are called “spectrum holes” or “white spaces”. The solution to this issue is provided by implementing CR technology. It allows users to determine the unused bands in spectrum, choose the suitable one (depending on availability and accessibility of the spectrum) and use them in the best way possible. Spectrum assignment plays a vital role in minimizing any possibility of interference between secondary and primary users. Because of the varying parameters of available spectrum along with the different QoS specifications of various networks, CR technology raise a range of challenges. Spectrum management functions should tackle these problems and ensure that the CR network runs smoothly. This article therefore presents a brief survey on CR networks, its architecture and other relevant functionalities like spectrum sensing, spectrum decision, spectrum sharing, and spectrum mobility.

WDM Network Issues: QOT Impairments, Dynamic Bandwidth Allocation, Modeling and Monitoring Schemes based on ML

Machine Learning (ML) has recently drawn the interest of both academics and professionals in the optical networking area to solve several problems. This trend has been triggered largely by the vast amount of available data (i.e., signal strength metrics, network alerts, etc.) and the large range of optimization criteria available in today's optical networks (such as modulation format, light path routes, transport wavelength, etc.). WDM systems are popular in the telecommunications industry. It increases network bandwidth without laying more cable. WDM technology in optical communication transports multiple optical carrier signals on a single fibre using various wavelengths of laser light. Wavelength division multiplexing (WDM) is an efficient strategy for leveraging the wide bandwidth of optical fibres to meet the rapid rise in demand for bandwidth on the Internet. WDM plays an essential role in both core and access networks in the communication network and faces various issues like its network performance is affected due to QoT impairments, Dynamic Bandwidth Allocation problem, Modeling, and Monitoring issues. Physical impairments are an issue in WDM and can cause calls to be blocked if the transmission quality is calculated in terms of minimum bit-error-rate. Dynamic allocation of bandwidth in WDM provides a crucial challenge for the effective and equal usage of the passive optical network upstream bandwidth when supporting the QoS specifications of various traffic groups. Fast attack monitoring can prevent the failure of vast volumes of data on all-optical networks. So, monitoring and modeling in a WDM network is also a critical issue. To solve these issues in WDM networks, more intelligence resources in scalable optical networks are necessary. ML techniques are demonstrating superiority in solving these issues. In this paper, a small detail about the WDM network is presented. Then, some WDM issues like QOT impairments, Dynamic Bandwidth Allocation, and modeling and monitoring are discussed, and then, in the next section focus on some ML techniques for solving these issues are presented.

Customer-Oriented Quality of Service Management Method for the Future Intent-Based Networking

The rapid development and spread of communication technologies is now becoming a global information revolution. Customers have a need for communication services, which could be flexibly configured in accordance with their Quality of Experience (QoE) requirements. Realizing the close connection between customer experience and profitability, the service provider has been placing more and more attention on customer experience and QoE. The traditional quality of service management method based on SLA (Service Level Agreement) is not sufficient as a means to provide QoE-related contracts between service providers and customers. The current SLA method is mostly limited and focused on technical aspects of QoS (Quality of Service). Furthermore, they do not follow on the network the principles and semantic approach to the QoS specification for a communication service using QoE parameters. In this paper, we propose a customer-oriented quality of service management method for future IBN (Intent-Based Networking). It is based on a new QoE metric on a scale from 1 to 5, which allows one to take into account the commercial value of e-services for customers. Based on this approach, the network configuration and functionality of network equipment automatically changes depending on customer requirements. To implement the new method of service quality management, an algorithm for routing data packets in the network was developed, taking into account the current load of the forecast path. The algorithm of billing system functioning in conditions of customer-oriented quality management in telecommunication networks has been created. To investigate the effectiveness of the proposed method of service quality management with the traditional SLA method, we developed a simulation network model with the implementation of two approaches. By conducting a simulation, it was determined that the proposed method gives an average gain of 2–5 times for the criterion of the number of customers who require high quality of experience of the service.

Managing QoS of Internet-of-Things Services Using Blockchain

Owing to the exponential growth of Internet of Things (IoTs), ensure that the Quality of Service (QoS) over IoT becomes challenges at the network edge or on cloud. The traditional mechanisms for QoS measurements rely on the centralized trusted third parties who use specialized agents to collect data and measure the performances of services. However, these mechanisms are ineffective to deal with highly dynamic and distributed nature of IoT-based services. Moreover, the dynamism of QoS needs to collect, update, and access reliable quality relevant data frequently, while lacking trust becomes a major hurdle for data utilization. It is our argument that the QoS measurement of IoT-based services would be decentralized and the trusts be built from collectively trusted subnetworks. In this paper, we propose to integrate the blockchain technologies (BCT) with a multi-agent approach to warrantee the trustiness of real-time data for the measurement of QoS in the IoT environment. The proposed approach is verified by some demonstrative examples in addressing QoS specification patterns commonly found in service-based applications (SBAs), where qualitative analyses are conducted for the evaluation of the patterns.

Energy Efficient Approach in Wireless Sensor Networks Using Game Theoretic Approach and Ant Colony Optimization

In the cluster based wireless sensor network architecture, an effective way to optimize the energy consumption is to implement an energy efficient scheme amongst the participating nodes for major activities such as construction of the hierarchical structure on the regular interval and the data communication from a node to the base station. This paper proposes an energy efficient approach for a cluster based wireless sensor network architecture by employing the game theory and ant colony optimization technique. Initially, the proposed work forms various clusters within the network and thereafter, the coalitions are formed using the proposed algorithm based on the game theory. The proposed algorithm considers the extent of spatially correlated sensed data that are generated by neighbouring nodes in order to form a coalition within a cluster. The proposed coalition scheme reduces the number of transmissions across the network. It is compared with the competing clustering protocols. The simulation results confirm that the proposed algorithm achieves the increased network lifetime under the specified quality of service specification (QSS). The results of the proposed work are compared with that obtained through the existing low energy adaptive clustering hierarchy (LEACH) and the deterministic stable election protocols (D-SEP). The overall improvement gain achieved by the proposed work is 31% and 10% at specified QSS, when compared with the LEACH and the D-SEP protocols respectively. Thus, the simulation results obtained in the proposed work confirm their superiority over the LEACH and the D-SEP protocols.

Transaction history-based web service composition for uncertain QoS

The QoS-aware web service composition WSC problem constructs a composite web service with the optimal accumulated QoS value. In the real world, this problem encounters some challenges. First, while most QoS-aware WSC techniques make their decisions based on the QoS information published by each service provider, the actual QoS performance at run-time may be inconsistent with the QoS specification due to the dynamic execution environment and intentional/unintentional error in the QoS declaration. Another obstacle is that the QoS-aware WSC problem for large scale instances is intractable to solve since the problem corresponds to a global optimisation problem. Toward these challenges, we propose a novel QoS-aware WSC method based on the real service transaction history of web services, which employs the anytime algorithm technique. In the experiment, our proposal can deal with the uncertain QoS efficiently and identify composite web services with high quality much earlier than the optimal algorithm.

Aggregated Quantified Response Time Matrix Formulation (ARMF) - A New Quality of Service Paradigm Technique

Workflow management system, a technique that manages different types of processes/jobs gathered as a workflow, ensures that each task in the workflow is accomplished to proceed further. When the process happens between two parties, the client and the server, a binding agreement or contract is defined specifying the Quality of Service (QoS) metrics such as products/services to be delivered, the deadlines and the cost of services. The goal of QoS is to select the appropriate web services for the customers achieve their goals. The existing service applications pretend to be a self-contained unit of functionalities that requests and retrieve a qualified service using service oriented architecture. But they face difficulties in identifying the right quality of a service based on functionality. Hence the major factor in QoS specification is QoS modeling, which involves the task of identifying the factors suitable for a functional requirement. QoS-aware service composition significantly affects the quality of a composite service and hence enormous research has been performed in this area. However, existing methods are restricted to predefined workflows, which can sustain the limitations. The limitations include the lack of guarantee for the optimality on overall QoS, satisfaction of customers and the completeness of finding a composite service solution. The proposed approach uses an Aggregated Quantified Response time Matrix Formulation (ARMF) methodology. The ARMF predicts the unknown QoS values by implementing two algorithms, the Aggregated Quantified Matrix Formulation (AQMF) Technique and the Optimal Incremental Multi-Attributes property Filtering (OIMF). It provides the user-response matrix where every entry in the matrix depicts the QoS value of the service opted by the user. The experimental results show that the proposed approach largely outperforms the existing techniques in terms of quality and efficiency required for the customer services.

Saas Quality of Service Attributes

Software as a Service (SaaS) is one of the cloud computing branch and it is rapidly growing. Quality of Service (QoS) for SaaS cloud is considered as an important concern among researchers. The QoS specification, particularly, for SaaS is known as a big gap in current researches. Therefore, in this study, the main QoS attributes for SaaS consisting of 33 attributes have been reviewed. The results show a comprehensive specification of QoS attributes for SaaS which cover more aspects of QoS for SaaS excluding the business perspective. The attributes then have been classified in terms of both user and provider perspectives and can be useful as a guideline for both users and providers.

QoS within Business Grid Quality of Service (BGQoS)

Differences in domain QoS requirements have been an obstacle to utilising Grid Computing for main stream applications. While the resource could potentially provide potentially vital services as well as providing significant computing and storage capabilities, the lack of high level QoS specification capabilities has proven to be a hindrance. Business Grid Quality of Service (BGQoS) is a QoS model for business-oriented applications on Grid computing systems. BGQoS defines QoS at a high level facilitating an easier request model for the Grid Resource Consumer (GRC) and eliminates confusion for the Grid Resource Provider in supplying the appropriate resources to meet the GRC requirements. It offers high level QoS specification within multi-domain environments in a flexible manner. Employing component separation and dynamic QoS calculation, it provides the necessary tools and execution environment for a scalable set of requirements tailoring to specific domain demands and requirements. Moreover, through reallocation, the model provides the insurance that all QoS requirements are met throughout the execution period, including migrating tasks to different resources if necessary. This process is not random and adheres to a set of conditions which ensures that task execution and resource allocation happen when and in accordance with execution requirements. This paper focuses on BGQoS’ flexibility and QoS capability. More specifically, the concentration is on core operations within BGQoS and the methods used in order to deliver a sustained level of QoS which meets the GRC’s requirements while being versatile and flexible such that it can be tailored to specific domains. This paper also presents an experimental evaluation of BGQoS. The evaluation investigates the behaviour and performance of the separate operations and components within BGQoS, and moreover, it presents an investigation and comparison between the different operations and their effect on the full model.

A Geometric Backoff Time Distribution of IEEE 802.11 DCF: An Analytical Study

Today’s networks, including WLANs, transport different classes of service. A service differentiation is then essential to provide QoS. However, IEEE 802.11 for WLANs was primarily designed for best effort traffic and did not provide QoS specifications. IEEE 802.11e MAC has been then described to support QoS in WLAN. In this paper, we propose a new scheme for service differentiation which is based on the 802.11 standard and requires minor modifications. In fact, we act on DCF which uses the backoff procedure to solve contention in WLANs. For this scheme, we use, instead of the uniform distribution, a geometric distribution for random backoff time selection. Using a multi-class system, we propose three parametrizations of the geometric distribution which imply different dynamic differentiation modes and we provide an analytical study, using a Markov chain model, to compare our differentiation modes. We discuss our numerical results which give the performances evaluation of the proposed mechanism in term of throughput and delay.

A semantic approach for QoS specification of communication services using QoE parameters

Abstract Various operations related to Quality of Service (QoS) management in communication networks require the clients/users to specify the quality level of the network service. The current QoS proposals adopt a fixed set of performance parameters at the network level to specify quality levels, avoiding dealing with the problem of heterogeneity among QoS parameters and metrics during the service management. However, in several situations where humans are the end-users of the service, the quality level should be specified using Quality of Experience (QoE) parameters, more natural for humans than network performance parameters. On the other hand, the QoS specification using QoE parameters is not sufficient to the service providers; they must translate QoE parameters into network parameters. This paper proposes a semantic approach to the automatic QoE/QoS mapping using the Network QoS Ontology (NetQoSOnt), offering automatic and extensible translation between QoE and QoS parameters. The use of our proposal is illustrated by supporting a voice over IP service negotiation.

Cross‐layer packet scheduler for QoS support over Digital Video Broadcasting‐Second Generation broadband satellite systems

SUMMARYThis article presents a cross‐layer packet scheduler to provide end‐to‐end QoS guarantees for Digital Video Broadcasting‐Second Generation (DVB‐S2) broadband satellite systems. The scheduler design is based on a cross‐layer mechanism defined between the physical and the network layer. It includes an algorithm to guarantee the required QoS specifications established in the service level agreement. The algorithm calculation depends basically on two parameters: the available bandwidth present in a DVB‐S2 satellite link and the QoS requirements of each traffic class defined by the satellite operator. The cross‐layer scheduler's operation is demonstrated using the NS‐2 simulator tool. The results show that the proposed mechanism maximizes the bandwidth utilization while enforcing the priority level of each service class when an extreme reduction of bandwidth caused by rain events is experienced. Copyright © 2012 John Wiley & Sons, Ltd.

A probabilistic strategy for temporal constraint management in scientific workflow systems

AbstractIn scientific workflow systems, it is critical to ensure the timely completion of scientific workflows. Therefore, temporal constraints as a type of QoS (Quality of Service) specification are usually required to be managed in scientific workflow systems. Specifically, temporal constraint management includes two basic tasks: setting temporal constraints at workflow build‐time and updating temporal constraints at workflow run‐time. For constraint setting, the current work mainly adopts user‐specified temporal constraints without considering the system performance. Hence, it may result in frequent temporal violations which deteriorate the overall workflow execution effectiveness. As regards constraint updating, although not well investigated, so far is in fact of great importance to workflow management tasks such as workflow scheduling and exception handling. In this paper, with a systematic analysis of the above issues, we propose a probabilistic strategy for temporal constraint management which utilizes a novel probability‐based temporal consistency model. Specifically for constraint setting, a negotiation process between the client and the service provider is designed to support the setting of coarse‐grained temporal constraints and then automatically derive the fine‐grained temporal constraints; for constraint updating, the probability time deficit/redundancy propagation process is proposed to update run‐time fine‐grained temporal constraints when workflow execution is either ahead of or behind the schedule. The effectiveness of our strategy is demonstrated through a case study on an example scientific workflow process in our scientific workflow system. Copyright © 2011 John Wiley & Sons, Ltd.

Load Shedding in Mobile Systems with MobiQual

In location-based, mobile continual query (CQ) systems, two key measures of quality-of-service (QoS) are: freshness and accuracy. To achieve freshness, the CQ server must perform frequent query reevaluations. To attain accuracy, the CQ server must receive and process frequent position updates from the mobile nodes. However, it is often difficult to obtain fresh and accurate CQ results simultaneously, due to 1) limited resources in computing and communication and 2) fast-changing load conditions caused by continuous mobile node movement. Hence, a key challenge for a mobile CQ system is: How do we achieve the highest possible quality of the CQ results, in both freshness and accuracy, with currently available resources? In this paper, we formulate this problem as a load shedding one, and develop MobiQual—a QoS-aware approach to performing both update load shedding and query load shedding. The design of MobiQual highlights three important features. 1) Differentiated load shedding: We apply different amounts of query load shedding and update load shedding to different groups of queries and mobile nodes, respectively. 2) Per-query QoS specification: Individualized QoS specifications are used to maximize the overall freshness and accuracy of the query results. 3) Low-cost adaptation: MobiQual dynamically adapts, with a minimal overhead, to changing load conditions and available resources. We conduct a set of comprehensive experiments to evaluate the effectiveness of MobiQual. The results show that, through a careful combination of update and query load shedding, the MobiQual approach leads to much higher freshness and accuracy in the query results in all cases, compared to existing approaches that lack the QoS-awareness properties of MobiQual, as well as the solutions that perform query-only or update-only load shedding.

QoS Specification in Software Architecture for QoS-aware Applications

QoS-aware applications have become urgently demanded especially in service oriented computing environment. Specifying software architectures of QoS-aware applications is not a trivial task because such architectures are complex and dynamic, evolving at runtime according to QoS values and changes. To specify architectures of QoS-aware applications requires to solve two problems i.e. how to specify QoS in the architectures and how to specify the dynamism of the architectures. The dynamism of the architectures can be modelled with primitive actions of Archware π-ADL. In this paper, through the definition of QoS enhanced architecture styles, π-ADL is extended with QoS specifications to facilitate the architecture modelling of QoS-aware applications, in which QoS specifications are handled as first class entities. The QoS-based architectural mismatch check is developed to detect some QoS violations at the stage of architecture design. A case study is given to illustrate how to describe QoS-aware architectures and how to do the QoS-based architectural mismatch check.

A Semantics and Data-Driven Biomedical Multimedia Software System

Developing a large-scale biomedical multimedia software system is always a challenging task: Satisfaction of sundry and stringent biomedical multimedia related requirements and standards; Heterogeneous software deployment and communication environments; and tangling correlation between data/contents and software functionalities, among others. This paper introduces a novel biomedical multimedia software system developed under Service-Oriented Architecture (SOA). Such a system takes the advantage of interoperability of SOA to solve the heterogeneity and correlation problems. The paper also classifies the system into services, annotation, ontologies, semantics matching, and QoS optimization aspects which may potentially solve the requirements problem: By establishing data ontology with respect to data properties, contents, QoS, and biomedical regulations and expanding service ontology to describe more functional and QoS specifications supported by services, appropriate services for processing biomedical multimedia data may be discovered, performed, tuned up or replaced as needed. Lastly, a biomedical education project that improves the performance of feature extraction and classification processed afterwards is introduced to illustrate the advantages of our software system developed under SOA.

End-to-end quality of service specification and mapping: The third party approach

This article addresses an open issue of end-to-end service specification and mapping in next generation networks. A centralized approach has been considered, via the third party agent that manages negotiation process in a group of domains. We suggest a general structure of the service specification form, which contains technical parameters related with a particular service request. Relying on such general form, we further propose and evaluate an efficient algorithm for service class selection. The algorithm selects the most appropriate class for each domain by determining the closest conformance between the required and offered service level. We also present a numerical example that demonstrates operating of the algorithm. Performance evaluation has been performed on the prototype implementation. Results of the analysis have pointed out the following important advantages of our approach: fairness in resource consumption, flexibility in class selection according to specific management policy and adaptability to different quality of service models.

Efficient multimedia transmission using adaptive packet bursting for wireless LANs

In addition to an unprecedented 600 Mb/s physical data rate in upcoming standards with greater than 1 Gb/s being considered for future systems, 802.11 has evolved from its earlier incarnations to become a ubiquitous, high-throughput wireless access technology utilized in heterogeneous networks. Although capable of advanced QoS provisioning, commercial 802.11 implementations often support only a subset of QoS specifications, utilize manufacturer-specific QoS enhancements, or use sub-optimal MAC reference specifications with limited capability in achieving optimal system throughput and QoS provisioning. Although more efficient ARQ modes have been defined in the 802.11e and imminent 802.11n amendment standards, opportunities exist within this framework for further optimization through dynamic adaptation of key ARQ-related parameters, which is out of scope of current 802.11 standard specifications. Considering such opportunities, this article presents a novel adaptive ARQ scheme designed to improve the quality and reliability of multimedia transmission through the real-time adaptation of the maximum packet burst size and actual ARQ mode employed. Comprehensive simulation studies show that this scheme can potentially improve the QoS and throughput performance of multimedia traffic in both existing and future 802.11 wireless LANs.

Efficient Packets Management over Wireless Heterogeneous Networks

With the wireless technology becoming more and more mature, uncountable numbers of wireless networks are used worldwide. Hence, QoS (Quality of Service) has become the most important topic that have to be seriously considered, such as the jitter, the packet loss ratio and the transmission rate. In this paper, we propose an EPM (Efficient Packets Management) mechanism to improve the transmission quality in the wireless heterogeneous networks. The heterogeneous architecture which we propose is based upon the ”WiMAX” (Worldwide Interoperability for Microwave Access) and the Wi-Fi with QoS specification (802.11e). We also propose a heterogeneous gateway named the Arbitrative Classify Gateway (AC-Gateway) in the wireless heterogeneous environment, and cooperate with our derived EPM mechanism to classify the streaming data from the media center, or the voice data from another base station (BS) according to the privilege. The packets will be scheduled efficiently and transmit correctly. Based on the architecture we propose, the transmission quality will be raised. Finally, we will give some powerful simulation results to prove our architecture works.

QoS-Driven Service Selection and Composition Using Quantitative Constraint Automata

Assuring Quality of Service (QoS) properties is critical in Service-Oriented Application (SOA) development. In this paper, we present an approach for specifying the QoS properties of services along multiple dimensions and selecting services for their composition in a way that optimizes the QoS of the result. We apply the integration of concerns paradigm to allow combined specification of QoS and functional properties by using Quantitative Constraint Automata, which integrate QoS aspects into service-oriented application development processes, mainly for service selection and composition.