From Enabling to Ensuring Grid Workflows

For the grid workflow system include a large of candidate services, the activity scheduling in workflow’s ex-ecution base on quality of service (QoS) constraints can pro-vide optimal service for users. This paper established the QoS’s parameter system with applied technology of grid workflow, and introduced the each parameter’s calculation model of activity’s QoS, the grid work-flow’s QoS estimation method based on the basic flow control structures defined by the abstract grid workflow language (AGWL). The experimental results show that the calculation method in this paper can estimate stably QoS parameter values of grid workflow combining with the multi candidate services, and, can provide a reasonable basis for process scheduling based on QoS constraints.

Currently the research on the grid workflow scheduling algorithms commonly suffer by one or several of the following drawbacks: grid workflow model of directed acyclic graph (DAG), not enough considerations of multi-dimensional Quality of Service (QoS) parameters and single objective optimal scheduling. Based on abstract grid workflow language (AGWL) model, this paper presents an algorithm for multi-objective optimal grid workflow scheduling with QoS constraints, which make uses of an improved NSGA-II algorithm. Theoretical analysis and experimental results indicate the feasibility and efficiency of the algorithm.KeywordsQuality of service (QoS)grid workflow schedulingNSGA-II

We propose a control method for high quality and highly effective video multicasting to satisfy various QoS requirements of clients. Our method employs an MPEG-2 hierarchical coding technique for that purpose. Further, flow aggregation is introduced to achieve application level QoS (Quality of Service) guarantees. Our method can guarantee the network level QoS only if underlying networks provide some guaranteed services as in ATM, Intserv and Diffserv. We investigate the effectiveness and applicability of our method on networks with various QoS guarantees.

In this paper, we propose an energy efficient user association scheme for uplink heterogeneous networks with machine-to-machine (M2M) and human-to-human (H2H) coexistence. A group based random access protocol is designed for massive number of machine-type-communications (MTC) user equipments' (UEs) transmissions. A user association problem for UEs' energy efficiency maximization is formulated considering the HTC UEs' quality of service (QoS) guarantees and load balance among multiple BSs, simultaneously. A distributed iterative algorithm is developed to solve the optimization problem. In addition, the convergence of the proposed algorithm is proved. Simulation results show that our proposed scheme outperforms other schemes in terms of energy efficiency and QoS guarantees.

ETXOP: A resource allocation protocol for QoS-sensitive services provisioning in 802.11 networks

Grid workflow applications are emerging as an important new alternative to develop truly distributed applications for the grid platform. The modeling of grid workflow system is a challenging task, due to the high degree of autonomy and heterogeneity of the cooperative organizations under distributed environments. This paper presents a formal specification methodology for grid workflow modeling which is founded upon the Pi-Calculus process algebra. This method works well for characterizing the behaviors and interactions of the grid workflow processes that belong to different organizations in terms of the semantics of Pi-Calculus.

In order to support mutimedia data transfers, the underlying network should support quality of service (QoS) guarantees. The QoS guarantees by the network and the associated systems (hardware/software) is a complex task. In this talk, I’ll outline the various issues related to the QoS in the Internet environment. The notion of QoS routing will be described in detail. Various options for routing and their associated overheads will be presented. Implementation issues will also be discussed.

We introduce a variety of mechanisms to enable scalable, adaptive, and reliable quality of service (QoS) guarantees across heterogeneous networking environments. The resultant scalable resource reservation scheme (SRRS) is the first resource management scheme that provides efficient fault protection based on the virtual reservation mechanism and a penalty-based adaptable reservation mechanism, so that QoS can continue to be guaranteed in the presence of faults without wasting expensive network resources unnecessarily. Based on the proposed geographical reservation mechanism and virtual IP addressing, SRRS can enable QoS guarantees in ad hoc mobile wireless networks. Also, resource reservation and allocation in SRRS are adaptive to the networking environments so that wireless QoS-guarantee issues can be resolved in the presence of mobility, making SRRS suitable for wireless mobile networks. We evaluate the performance of SRRS based on simulation and analysis, and show that SRRS can achieve considerably lower blocking rates as compared to previous reservation protocols.

The Grid can be seen as a collection of services each of which performs some functionality. Grid users often submit their applications in the form of workflows with certain Quality of Service (QoS) requirements imposed on the workflows. These workflows detail the composition of Grid services and the level of service required from the Grid. This paper addresses workload allocation techniques for Grid workflows. We model a Grid service as a G/G/1 queue and minimise failures (QoS requirement violation) of jobs by solving a mixed-integer non-linear program (MINLP). The novel approach is evaluated through an experimental simulation and the results confirm that the proposed workload allocation strategy performs considerably better in terms of satisfying QoS requirements of Grid workflows than scheduling algorithms that don?t employ such workload allocation techniques.

Many important scientific and engineering problems may be solved by combining multiple applications in the form of a Grid workflow. We consider that for the wide acceptance of Grid technology it is important that the user has the possibility to express requirements on Quality of Service (QoS) at workflow specification time. However, most of the existing workflow languages lack constructs for QoS specification. In this paper we present an approach for high level workflow specification that considers a comprehensive set of QoS requirements. Besides performance related QoS, it includes economical, legal and security aspects. For instance, for security or legal reasons the user may express the location affinity regarding Grid resources on which certain workflow tasks may be executed. Our QoS-aware workflow system provides support for the whole workflow life cycle from specification to execution. Workflow is specified graphically, in an intuitive manner, based on a standard visual modeling language. A set of QoS-aware service-oriented components is provided for workflow planning to support automatic constraint-based service negotiation and workflow optimization. For reducing the complexity of workflow planning, we introduce a QoS-aware workflow reduction technique. We illustrate our approach with a real-world workflow for maxillo facial surgery simulation.

Third generation (3G) wireless networks have been designed to provide high speed data services on both forward and reverse links. In addition to increased data capacity they also support QoS (quality of service) guarantees for user applications. Users may run multiple applications (service instances) simultaneously and QoS guarantees must be assured for one or more of them. In order to maintain these QoS guarantees for each user's service instance, the radio resources assigned to the mobile must be adjusted in real time. However, the forward packet data channel in 3G systems are time-shared among all mobiles. Furthermore, the forward link channel conditions of the mobile changes over time. This implies that the forward link throughput available to the mobile is stochastic. In this paper, we address the linkage between the application demands (i.e., based on the QoS attribute guarantees) and the available channel capacity (i.e., resources assigned by the scheduler) and present a simple solution to the problem.

Grid workflow applications are emerging as one of the most interesting programming models for the Grid. In this paper we present a novel approach for graphically modeling and describing Grid workflow applications based on the Unified Modeling Language (UML). Our approach provides a graphic representation of Grid applications based on a widely accepted standard (UML) that is more amenable than pure textual-oriented specifications (such as XML). We describe some of the most important elements for modeling control flow, data flow, synchronization, notification, and constraints. We also introduce new features that have not been included by other Grid workflow specification languages which includes broadcast and parallel loops. Our UML-based graphical editor Teuta provides the corresponding tool support. We demonstrate our approach by describing a UML-based Grid workflow model for an advanced 3D medical image reconstruction application.

Applications communicating over connectionless networks, such as IP, cannot obtain per-connection Quality of Service (QoS) guarantees. In contrast, the connection-oriented nature of the ATM layer and its per-virtual-circuit QoS guarantees are visible to a native-mode ATM application. We describe the design and implementation of operating system and signaling support for native-mode applications, independent of the semantics of the protocol layers or of the signaling protocol. The work was done in the context of a Unix-like operating system and the Xunet 2 wide-area high-speed ATM network. The IPC-based interface between an application and the signaling entity allows processes to request parameterized virtual circuits, and the signaling-kernel interface allows resources to be reclaimed from prematurely terminating processes. We also built a simple encapsulation layer over raw IP that allows any host with IP access to send AAL frames into the wide-area network with little performance degradation. Our design makes it simple to port existing TCP/IP socket applications to a native-mode ATM protocol stack and also enables interoperation of existing IP networks with our ATM network. Our experience has been positive - the design is robust, easily extendible and scales well with the number of open connections.

Using GENI for experimental evaluation of Software Defined Networking in smart grids

To support Quality of service (QoS)‐sensitive applications like real‐time video streaming in IEEE 802.11 networks, a MAC layer extension for QoS, IEEE 802.11e, has been recently ratified as a standard. This MAC layer solution, however, addresses only the issue of prioritized access to the wireless medium and leaves such issues as QoS guarantee and admission control to the traffic control systems at the higher layers. This paper presents an IP‐layer traffic control system for IEEE 802.11 networks based on available bandwidth estimation. We build an analytical model for estimating the available bandwidth by extending an existing throughput computation model, and implement a traffic control system that provides QoS guarantees and admission control by utilizing the estimated available bandwidth information. We have conducted extensive performance evaluation of the proposed scheme via both simulations and measurements in the real test‐bed. The experiment results show that our estimation model and traffic control system work accurately and effectively in various network load conditions without IEEE 802.11e. The presence of IEEE 802.11e will allow even more efficient QoS provision, as the proposed scheme and the MAC layer QoS support will complement each other. Copyright © 2006 John Wiley & Sons, Ltd.