End-to-End QoS Support for a Medical Grid Service Infrastructure

Quality of Service support is an important prerequisite for the adoption of Grid technologies for medical applications. The GEMSS Grid infrastructure addressed this issue by offering end-to-end QoS in the form of explicit timeliness guarantees for compute-intensive medical simulation services. Within GEMSS, parallel applications installed on clusters or other HPC hardware may be exposed as QoS-aware Grid services for which clients may dynamically negotiate QoS constraints with respect to response time and price using Service Level Agreements. The GEMSS infrastructure and middleware is based on standard Web services technology and relies on a reservation based approach to QoS coupled with application specific performance models. In this paper we present an overview of the GEMSS infrastructure, describe the available QoS and security mechanisms, and demonstrate the effectiveness of our methods with a Grid-enabled medical imaging service

A service-oriented Grid environment with on-demand QoS support

Grid Computing entstand aus der Vision für eine neuartige Recheninfrastruktur, welche darauf abzielt, Rechenkapazität so einfach wie Elektrizität im Stromnetz (power grid) verfügbar zu machen. Der entsprechende Zugriff auf global verteilte Rechenressourcen versetzt Forscher rund um den Globus in die Lage, neuartige Herausforderungen aus Wissenschaft und Technik in beispiellosem Ausmaß in Angriff zu nehmen. Die rasanten Entwicklungen im Grid Computing begünstigten auch Standardisierungsprozesse in Richtung Harmonisierung durch Service-orientierte Architekturen und die Anwendung kommerzieller Web Services Technologien. In diesem Kontext ist auch die Sicherung von Qualität bzw. entsprechende Vereinbarungen über die Qualität eines Services (QoS) wichtig, da diese vor allem für komplexe Anwendungen aus sensitiven Bereichen, wie der Medizin, unumgänglich sind. Diese Dissertation versucht zur Entwicklung im Grid Computing beizutragen, indem eine Grid Umgebung mit Unterstützung für QoS vorgestellt wird. Die vorgeschlagene Grid Umgebung beinhaltet eine sichere Service-orientierte Infrastruktur, welche auf Web Services Technologien basiert, sowie bedarfsorientiert und automatisiert HPC Anwendungen als Grid Services bereitstellen kann. Die Grid Umgebung zielt auf eine kommerzielle Nutzung ab und unterstützt ein durch den Benutzer initiiertes, fallweises und dynamisches Verhandeln von Serviceverträgen (SLAs). Das Design der QoS Unterstützung ist generisch, jedoch berücksichtigt die Implementierung besonders die Anforderungen von rechenintensiven und zeitkritischen parallelen Anwendungen, bzw. Garantien f¨ur deren Ausführungszeit und Preis. Daher ist die QoS Unterstützung auf Reservierung, anwendungsspezifische Abschätzung und Preisfestsetzung von Ressourcen angewiesen. Eine entsprechende Evaluation demonstriert die Möglichkeiten und das rationale Verhalten der QoS Infrastruktur. Die Grid Infrastruktur und insbesondere die QoS Unterstützung wurde in Forschungs- und Entwicklungsprojekten der EU eingesetzt, welche verschiedene Anwendungen aus dem medizinischen und bio-medizinischen Bereich als Services zur Verfügung stellen. Die EU Projekte GEMSS und Aneurist befassen sich mit fortschrittlichen HPC Anwendungen und global verteilten Daten aus dem Gesundheitsbereich, welche durch Virtualisierungstechniken als Services angeboten werden. Die Benutzung von Gridtechnologie als Basistechnologie im Gesundheitswesen ermöglicht Forschern und Ärzten die Nutzung von Grid Services in deren Arbeitsumfeld, welche letzten Endes zu einer Verbesserung der medizinischen Versorgung führt.Grid computing emerged as a vision for a new computing infrastructure that aims to make computing resources available as easily as electric power through the power grid. Enabling seamless access to globally distributed IT resources allows dispersed users to tackle large-scale problems in science and engineering in unprecedented ways. The rapid development of Grid computing also encouraged standardization, which led to the adoption of a service-oriented paradigm and an increasing use of commercial Web services technologies. Along these lines, service-level agreements and Quality of Service are essential characteristics of the Grid and specifically mandatory for Grid-enabling complex applications from certain domains such as the health sector. This PhD thesis aims to contribute to the development of Grid technologies by proposing a Grid environment with support for Quality of Service. The proposed environment comprises a secure service-oriented Grid infrastructure based on standard Web services technologies which enables the on-demand provision of native HPC applications as Grid services in an automated way and subject to user-defined QoS constraints. The Grid environment adopts a business-oriented approach and supports a client-driven dynamic negotiation of service-level agreements on a case-by-case basis. Although the design of the QoS support is generic, the implementation emphasizes the specific requirements of compute-intensive and time-critical parallel applications, which necessitate on-demand QoS guarantees such as execution time limits and price constraints. Therefore, the QoS infrastructure relies on advance resource reservation, application-specific resource capacity estimation, and resource pricing. An experimental evaluation demonstrates the capabilities and rational behavior of the QoS infrastructure. The presented Grid infrastructure and in particular the QoS support has been successfully applied and demonstrated in EU projects for various applications from the medical and bio-medical domains. The EU projects GEMSS and Aneurist are concerned with advanced e-health applications and globally distributed data sources, which are virtualized by Grid services. Using Grid technology as enabling technology in the health domain allows medical practitioners and researchers to utilize Grid services in their clinical environment which ultimately results in improved healthcare

Multimodal and multidimensional geodata interaction and visualization

This PhD proposes the development of a Science Data Visualization System, SdVS, that analyzes and presents different kinds of visualizing and interacting techniques with Geo-data, in order to deal with knowledge about Geo-data using GoogleEarth. After that, we apply the archaeological data as a case study, and, as a result, we develop the Archaeological Visualization System, ArVS, using new visualization paradigms and Human-Computer-Interaction techniques based on SdVS. Furthermore, SdVS provides guidelines for developing any other visualization and interacting applications in the future, and how the users can use SdVS system to enhance the understanding and dissemination of knowledge

Job-Management in einem Grid-System, realisiert als Web-Servlet und MIDlet

Grid-Systeme sind durch ihren dezentralen Charakter bestimmt. Eine zentrales Job- und User-Management ist daher nicht vorgesehen. Diverse Szenarien sprechen jedoch für dessen Sinnhaftigkeit. Der Job-Manager ermöglicht eine Visualisierung der Nutzung von Diensten in dem Vienna Grid Environment (VGE). Das VGE ist ein Software-System zur Realisierung einer Grid-Umgebung und wurde vom Institut für Scientific Computing der Universität Wien entwickelt. Der Job-Manager bietet die Möglichkeit, auf einfache Weise Jobs in einem Grid-System zu zentralisieren bzw. zu visualisieren und gemeinsam zu verwalten. Die Nutzung von Services bzw. die daraus resultierenden Jobs werden protokolliert und relevante Job-Daten persistent gespeichert. Jobs von mehreren Clients gestartet, können gemeinsam mit dem Job-Manager administriert werden; d.h. den aktuellen Status abfragen, auf die Ergebnisse zugreifen bzw. den Job abbrechen. Der Job-Manager ermöglicht dem Benutzer, seine Jobs oder die Jobs von anderen Benutzern, für die er berechtigt ist, zu administrieren. Eine Benutzerverwaltung ist eine zusätzliche Funktionalität, durch die eine Authentifizierung des Benutzers ermöglicht wird. Der Job-Manager ist in zwei Ausprägungen realisiert: als Web-Client und als Client für mobile Endgeräte. Der Client für mobile Endgeräte, auch als „Personal Job Manager“ bezeichnet, ermöglicht einem Benutzer, die durch ihn initiierten Jobs „over-the-air“ zu administrieren. Zur Realisierung des Job-Managers wurden Technologien wie Web Services, SOAP, WSDL und UDDI als auch die Übertragung von Attachments durch MIME, DIME und MTOM behandelt. Grid-Systeme, WSRF, OGSA-DAI, sind weitere, untersuchte Technologieschwerpunkte, ebenso wie die Realisierung von Java-Applikationen für mobile Endgeräte

Service-Oriented Ad Hoc Grid Computing

Subject of this thesis are the design and implementation of an ad hoc Grid infrastructure. The vision of an ad hoc Grid further evolves conventional service-oriented Grid systems into a more robust, more flexible and more usable environment that is still standards compliant and interoperable with other Grid systems. A lot of work in current Grid middleware systems is focused on providing transparent access to high performance computing (HPC) resources (e.g. clusters) in virtual organizations spanning multiple institutions. The ad hoc Grid vision presented in this thesis exceeds this view in combining classical Grid components with more flexible components and usage models, allowing to form an environment combining dedicated HPC-resources with a large number of personal computers forming a "Desktop Grid". Three examples from medical research, media research and mechanical engineering are presented as application scenarios for a service-oriented ad hoc Grid infrastructure. These sample applications are also used to derive requirements for the runtime environment as well as development tools for such an ad hoc Grid environment. These requirements form the basis for the design and implementation of the Marburg ad hoc Grid Environment (MAGE) and the Grid Development Tools for Eclipse (GDT). MAGE is an implementation of a WSRF-compliant Grid middleware, that satisfies the criteria for an ad hoc Grid middleware presented in the introduction to this thesis. GDT extends the popular Eclipse integrated development environment by components that support application development both for traditional service-oriented Grid middleware systems as well as ad hoc Grid infrastructures such as MAGE. These development tools represent the first fully model driven approach to Grid service development integrated with infrastructure management components in service-oriented Grid computing. This thesis is concluded by a quantitative discussion of the performance overhead imposed by the presented extensions to a service-oriented Grid middleware as well as a discussion of the qualitative improvements gained by the overall solution. The conclusion of this thesis also gives an outlook on future developments and areas for further research. One of these qualitative improvements is "hot deployment" the ability to install and remove Grid services in a running node without interrupt to other active services on the same node. Hot deployment has been introduced as a novelty in service-oriented Grid systems as a result of the research conducted for this thesis. It extends service-oriented Grid computing with a new paradigm, making installation of individual application components a functional aspect of the application. This thesis further explores the idea of using peer-to-peer (P2P networking for Grid computing by combining a general purpose P2P framework with a standard compliant Grid middleware. In previous work the application of P2P systems has been limited to replica location and use of P2P index structures for discovery purposes. The work presented in this thesis also uses P2P networking to realize seamless communication accross network barriers. Even though the web service standards have been designed for the internet, the two-way communication requirement introduced by the WSRF-standards and particularly the notification pattern is not well supported by the web service standards. This defficiency can be answered by mechanisms that are part of such general purpose P2P communication frameworks. Existing security infrastructures for Grid systems focus on protection of data during transmission and access control to individual resources or the overall Grid environment. This thesis focuses on security issues within a single node of a dynamically changing service-oriented Grid environment. To counter the security threads arising from the new capabilities of an ad hoc Grid, a number of novel isolation solutions are presented. These solutions address security issues and isolation on a fine-grained level providing a range of applicable basic mechanisms for isolation, ranging from lightweight system call interposition to complete para-virtualization of the operating systems

Cost-effective resource management for distributed computing

Current distributed computing and resource management infrastructures (e.g., Cluster and Grid) suffer from a wide variety of problems related to resource management, which include scalability bottleneck, resource allocation delay, limited quality-of-service (QoS) support, and lack of cost-aware and service level agreement (SLA) mechanisms. This thesis addresses these issues by presenting a cost-effective resource management solution which introduces the possibility of managing geographically distributed resources in resource units that are under the control of a Virtual Authority (VA). A VA is a collection of resources controlled, but not necessarily owned, by a group of users or an authority representing a group of users. It leverages the fact that different resources in disparate locations will have varying usage levels. By creating smaller divisions of resources called VAs, users would be given the opportunity to choose between a variety of cost models, and each VA could rent resources from resource providers when necessary, or could potentially rent out its own resources when underloaded. The resource management is simplified since the user and owner of a resource recognize only the VA because all permissions and charges are associated directly with the VA. The VA is controlled by a ’rental’ policy which is supported by a pool of resources that the system may rent from external resource providers. As far as scheduling is concerned, the VA is independent from competitors and can instead concentrate on managing its own resources. As a result, the VA offers scalable resource management with minimal infrastructure and operating costs. We demonstrate the feasibility of the VA through both a practical implementation of the prototype system and an illustration of its quantitative advantages through the use of extensive simulations. First, the VA concept is demonstrated through a practical implementation of the prototype system. Further, we perform a cost-benefit analysis of current distributed resource infrastructures to demonstrate the potential cost benefit of such a VA system. We then propose a costing model for evaluating the cost effectiveness of the VA approach by using an economic approach that captures revenues generated from applications and expenses incurred from renting resources. Based on our costing methodology, we present rental policies that can potentially offer effective mechanisms for running distributed and parallel applications without a heavy upfront investment and without the cost of maintaining idle resources. By using real workload trace data, we test the effectiveness of our proposed rental approaches. Finally, we propose an extension to the VA framework that promotes long-term negotiations and rentals based on service level agreements or long-term contracts. Based on the extended framework, we present new SLA-aware policies and evaluate them using real workload traces to demonstrate their effectiveness in improving rental decisions

Support for flexible and transparent distributed computing

Modern distributed computing developed from the traditional supercomputing community rooted firmly in the culture of batch management. Therefore, the field has been dominated by queuing-based resource managers and work flow based job submission environments where static resource demands needed be determined and reserved prior to launching executions. This has made it difficult to support resource environments (e.g. Grid, Cloud) where the available resources as well as the resource requirements of applications may be both dynamic and unpredictable. This thesis introduces a flexible execution model where the compute capacity can be adapted to fit the needs of applications as they change during execution. Resource provision in this model is based on a fine-grained, self-service approach instead of the traditional one-time, system-level model. The thesis introduces a middleware based Application Agent (AA) that provides a platform for the applications to dynamically interact and negotiate resources with the underlying resource infrastructure. We also consider the issue of transparency, i.e., hiding the provision and management of the distributed environment. This is the key to attracting public to use the technology. The AA not only replaces user-controlled process of preparing and executing an application with a transparent software-controlled process, it also hides the complexity of selecting right resources to ensure execution QoS. This service is provided by an On-line Feedback-based Automatic Resource Configuration (OAC) mechanism cooperating with the flexible execution model. The AA constantly monitors utility-based feedbacks from the application during execution and thus is able to learn its behaviour and resource characteristics. This allows it to automatically compose the most efficient execution environment on the fly and satisfy any execution requirements defined by users. Two policies are introduced to supervise the information learning and resource tuning in the OAC. The Utility Classification policy classifies hosts according to their historical performance contributions to the application. According to this classification, the AA chooses high utility hosts and withdraws low utility hosts to configure an optimum environment. The Desired Processing Power Estimation (DPPE) policy dynamically configures the execution environment according to the estimated desired total processing power needed to satisfy users’ execution requirements. Through the introducing of flexibility and transparency, a user is able to run a dynamic/normal distributed application anywhere with optimised execution performance, without managing distributed resources. Based on the standalone model, the thesis further introduces a federated resource negotiation framework as a step forward towards an autonomous multi-user distributed computing world

Simulated Annealing

The book contains 15 chapters presenting recent contributions of top researchers working with Simulated Annealing (SA). Although it represents a small sample of the research activity on SA, the book will certainly serve as a valuable tool for researchers interested in getting involved in this multidisciplinary field. In fact, one of the salient features is that the book is highly multidisciplinary in terms of application areas since it assembles experts from the fields of Biology, Telecommunications, Geology, Electronics and Medicine