Jorge Raúl Ardenghi

Extending an SSI Cluster for Resource Discovery in Grid Computing

Grid technologies enable large-scale sharing of resources within formal or informal consortia of individuals and/or virtual organizations. In these settings, the discovery, characterization, and monitoring of resources, services, and computations can be challenging due to the considerable diversity, large numbers, dynamic behavior, and geographical distribution of the entities in which a user might be interested. Hence, information services are a vital part of any grid software infrastructure, providing fundamental mechanisms for discovery and monitoring, and thus for planning and adapting application behavior. This paper proposes a resource discovery system for grid computing with fault-tolerant capabilities starting from an SSI clustering operating system. The proposed system uses dynamic leader-determination and registration mechanisms to automatically recover from nodes and network failures. The system is centralized and uses dynamic (or soft-state) registration to detect and recover from failures. Provisional or backup leader determination provides tolerance and recovery in the event of the leader node failing. The system was tested against a control network modeled after existing grid computing resource discovery components, such as Globus monitoring and discovery system (MDS). In various failure scenarios, the proposed system showed better resilience and performance than the control system

A Novel Algorithm for Indirect Reputation-Based Grid Resource Management

Component-based programming has been applied to address the requirements of applications in high performance computing (HPC). The usual service connectors of commercial component models do not fit some requirements of HPC, mainly regarding the support of parallelism, however. This paper looks at extensions to the usual notion of service connector to meet such requirements, using the # component model as a substratum, evidencing its expressiveness.A computational grid is a distributed infrastructure that appears to the end user as one large computing resource across organization boundaries. Grid technologies enable large-scale sharing of resources within formal or informal consortia of individuals and/or institutions, usually called virtual organizations. In these settings, the discovery, characterization, management, and monitoring of resources, services, and computations can be challenging due to the considerable diversity, large numbers, dynamic behavior, and geographical distribution of the entities in which a user might be interested. Trust is one of the biggest concerns in the grid resource management field. Grid systems can employ reputation mechanisms in order to provide this essential trust, but not usually without incurring in certain additional costs that negate the potential performance gains offered by grid computing technologies. Moreover, current reputation mechanisms are not appropriate for resource management in large-scale systems. In this paper, we present a new reputation model for resource management based on a economy model. Also we demonstrate how it can by employed to add trust into algorithms for grid scheduling. Finally, we simulate the proposed resource management algorithm in order to verify its effectiveness.

Government Data Interoperability: a Case Study from Academia

Data interoperability allows information sharing between different organizations, both public and private, for mutual benefits. This paper presents a case study providing an initial level of government data interoperability. SIGEVA is a set of applications for the management and evaluation of researchers and projects in the National Research Council (CONICET) in Argentina. The relevance of the case relies on promoting overcoming barriers in data exchange, although it exhibits several drawbacks. The case study is analyzed focusing in data interoperability; particularly in how to model a middleware to improve data interoperability between organizations with heterogeneous software applications. We show that data interoperability between organizations is a tendency to improve the activities of end-user, breaking down information silos. Furthermore, the solution requires to consider the levels of interoperability and barriers during the development process. Finally, in view of the detected problem, we propose a data interoperability solution with the properties of ensuring semantic consistency and overcoming heterogeneity.

ROLE PROCESSES FOR SHARING A RESOURCE BETWEEN A GROUP OF PROCESSES

Distributed systems are in continuous growth and new requirements emerge. Initially, in multiprogramming, the mutual exclusion problem was the aim to solve. Then, different extensions and variations come up, like k-mutual exclusion, and group mutual exclusion. In this paper, the proposal is based on an extension to group mutual exclusion (GME) where processes join a group with a role (shared, exclusive) in each stage. The properties that must guarantee a solution to GME are: mutual exclusion, bounded delay, progress and concurrency. For this extension, it requires a new property: role mutual exclusion. A general model to solve the problem is composed of two players: groups and processes. This model can be applied to the different communication mechanisms (shared memory, messages). Examples of implementations based on messages, and shared memory are presented. The shared memory proposed solution is based on an adaptive bakery algorithm.

On Indirect Reputation-Based Grid Resource Management

Grid technologies enable large-scale sharing of resources within formal or informal consortia of individuals and/or institutions, usually called virtual organizations.In these settings, the discovery, characterization,management, and monitoring of resources,services, and computations can be challenging due to the considerable diversity, large numbers, dynamic behavior,and geographical distribution of the entities in which a user might be interested.Trust is one of the biggest concerns in the grid resource management field. Grid systems can employ reputation mechanisms in order to provide this essential trust, but not usually without incurring in certain additional costs that negate the potential performance gains offered by grid computing technologies. Moreover,current reputation mechanisms are not appropriate for resource management in large-scale systems (generally used in P2P).In this paper, we present a new reputation model for resource management based on a economy model, which can be employed to add trust into algorithms for grid scheduling. Finally, we simulate the proposed resource management algorithm in order to verify its effectiveness.

Un modelo para el análisis de la confiabilidad de Ethernet Industrial en topología de anillo

Industrial Ethernet is been increasingly used for applications of automatization, either in manufacturing or processes industries. Besides the requirements of bandwidth, and real time traffic handling, these environments also present very strong requirements about reliability, due to the inherent risks of such activities. The ring topology is adequate for this type of networks, because it has a redundant connection that provides for a given fault tolerance. In the present work the reliability of Industrial Ethernet on ring topology is analyzed, with the aim to obtain useful results to the network design and selection of components, and also to allow to estimate the needed repairs. In the first step, the proposed model only considers the links, in order to analyze the reliability of the communication between switches. Later, the switches are included in order to analyze the reliability of the communication between field devices of through the network. The response time for the solution of a fault is one of the basic components of the considered model.

Descubrimiento de Recursos en un Entorno Grid mediante Ontolog´ıas

Las tecnolog´ias Grid permiten el uso compartido de recursos heterog´eneos que se encuentran dise- minados geogr´aficamente en una WAN o en Internet. La infraestructura determinada por el uso de estas tecnolog´ias (computaci´on grid) es solamente una parte de un escenario m´as amplio en el que tambi´en se incluye el manejo de informaci´on y soporte para el procesamiento de conocimiento por parte de los procesos distribuidos. Esta visi´on m´as amplia es adoptada por la grid sem´antica [6] que se describe como una extensi´on de la computaci´on grid donde la informaci´on y los servicios son descriptos de forma bien definida, permitiendo trabajar a las personas y a las computadoras de una manera m´as cooperativa. En este art´iculo se analizan las recientes propuestas en el manejo de ontolog´ias para describir de forma sem´antica los recursos que forman parte del entorno grid, lo cu´al facilita la localizaci´on de los mismos cuando las aplicaciones necesitan de ellos, y se exploran las posibilidades de desarrollo de m´odulos que hagan uso de bases de conocimiento. De esta forma, es posible extender arquitecturas grid existentes con el fin de hacer m´as eficiente la tarea de descubrir recursos en la web y componerlos en forma inteligente.

Latin American Perspectives on Grid Computing, from Bahia Blanca, Argentina

A computational grid is a distributed infrastructure that appears to the end user as one large computing resource across organization boundaries. Grid technologies enable large-scale sharing of resources within formal or informal consortia of individuals and/or institutions, usually called virtual organizations. In these settings, the discovery, characterization, and monitoring of resources, services, and computations can be challenging due to the considerable diversity, large numbers, dynamic behavior, and geographical distribution of the entities in which a user might be interested. This work explores the grid computing current state and perspectives in Latin America. In particular, we describe potential grid application areas and the experiences of our group in this promising field of research. Also, considering that grid trends are showing the importance of grid services we also identify some limitations and future research directions on this domain.

Telemedicina: aprovechando las tecnologías para favorecer el impacto social

En general la palabra telemedicina se asocia con cuestiones muy complejas y sofisticadas, como por ejemplo la realizacion de una cirugia a distancia, en la que estan involucrados sistemas de comunicacion, visualizacion y robotica basados en tecnologias de punta y de costos muy elevados. Si bien este tipo de aplicaciones es una de las mas notorias dentro del campo de la telemedicina, tiene por ahora un costo muy elevado y un impacto social muy bajo. Si se plantea como un objetivo de la telemedicina acercar lacatencion medica a poblaciones alejadas de los centros urbanos, y que por lo general cuentan con recursos economicos limitados, el punto de vista es otro. En lugar de buscar el desarrollo de nuevas tecnologias de punta se debe tratar de aprovechar y potenciar las tecnologias existentes. Como la base de cualquier sistema de telemedicina es la infraestructura de comunicaciones, en el presente trabajo se analizan las posibilidades de algunas tecnologias de comunicacion e incluso la complementacion entre ellas.