62,382 research outputs found
MonALISA : A Distributed Monitoring Service Architecture
The MonALISA (Monitoring Agents in A Large Integrated Services Architecture)
system provides a distributed monitoring service. MonALISA is based on a
scalable Dynamic Distributed Services Architecture which is designed to meet
the needs of physics collaborations for monitoring global Grid systems, and is
implemented using JINI/JAVA and WSDL/SOAP technologies. The scalability of the
system derives from the use of multithreaded Station Servers to host a variety
of loosely coupled self-describing dynamic services, the ability of each
service to register itself and then to be discovered and used by any other
services, or clients that require such information, and the ability of all
services and clients subscribing to a set of events (state changes) in the
system to be notified automatically. The framework integrates several existing
monitoring tools and procedures to collect parameters describing computational
nodes, applications and network performance. It has built-in SNMP support and
network-performance monitoring algorithms that enable it to monitor end-to-end
network performance as well as the performance and state of site facilities in
a Grid. MonALISA is currently running around the clock on the US CMS test Grid
as well as an increasing number of other sites. It is also being used to
monitor the performance and optimize the interconnections among the reflectors
in the VRVS system.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 8 pages, pdf. PSN MOET00
Towards Adaptable and Adaptive Policy-Free Middleware
We believe that to fully support adaptive distributed applications,
middleware must itself be adaptable, adaptive and policy-free. In this paper we
present a new language-independent adaptable and adaptive policy framework
suitable for integration in a wide variety of middleware systems. This
framework facilitates the construction of adaptive distributed applications.
The framework addresses adaptability through its ability to represent a wide
range of specific middleware policies. Adaptiveness is supported by a rich
contextual model, through which an application programmer may control precisely
how policies should be selected for any particular interaction with the
middleware. A contextual pattern mechanism facilitates the succinct expression
of both coarse- and fine-grain policy contexts. Policies may be specified and
altered dynamically, and may themselves take account of dynamic conditions. The
framework contains no hard-wired policies; instead, all policies can be
configured.Comment: Submitted to Dependable and Adaptive Distributed Systems Track, ACM
SAC 200
Organization of Multi-Agent Systems: An Overview
In complex, open, and heterogeneous environments, agents must be able to
reorganize towards the most appropriate organizations to adapt unpredictable
environment changes within Multi-Agent Systems (MAS). Types of reorganization
can be seen from two different levels. The individual agents level
(micro-level) in which an agent changes its behaviors and interactions with
other agents to adapt its local environment. And the organizational level
(macro-level) in which the whole system changes it structure by adding or
removing agents. This chapter is dedicated to overview different aspects of
what is called MAS Organization including its motivations, paradigms, models,
and techniques adopted for statically or dynamically organizing agents in MAS.Comment: 12 page
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Intelligent multimedia communication for enhanced medical e-collaboration in back pain treatment
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2004 SAGE PublicationsRemote, multimedia-based, collaboration in back pain treatment is an option which only recently has come to the attention of clinicians and IT providers. The take-up of such applications will inevitably depend on their ability to produce an acceptable level of service over congested and unreliable public networks. However, although the problem of multimedia application-level performance is closely linked to both the user perspective of the experience as well as to the service provided by the underlying network, it is rarely studied from an integrated viewpoint. To alleviate this problem, we propose an intelligent mechanism that integrates user-related requirements with the more technical characterization of quality of service, obtaining a priority order of low-level quality of service parameters, which would ensure that user-centred quality of perception is maintained at an optimum level. We show how our framework is capable of suggesting appropriately tailored transmission protocols, by incorporating user requirements in the remote delivery of e-health solutions
An Open Framework for Integrating Widely Distributed Hypermedia Resources
The success of the WWW has served as an illustration of how hypermedia functionality can enhance access to large amounts of distributed information. However, the WWW and many other distributed hypermedia systems offer very simple forms of hypermedia functionality which are not easily applied to existing applications and data formats, and cannot easily incorporate alternative functions which would aid hypermedia navigation to and from existing documents that have not been developed with hypermedia access in mind. This paper describes the extension to a distributed environment of the open hypermedia functionality of the Microcosm system, which is designed to support the provision of hypermedia access to a wide range of source material and application, and to offer straightforward extension of the system to incorporate new forms of information access
DIAMOnDS - DIstributed Agents for MObile & Dynamic Services
Distributed Services Architecture with support for mobile agents between
services, offer significantly improved communication and computational
flexibility. The uses of agents allow execution of complex operations that
involve large amounts of data to be processed effectively using distributed
resources. The prototype system Distributed Agents for Mobile and Dynamic
Services (DIAMOnDS), allows a service to send agents on its behalf, to other
services, to perform data manipulation and processing. Agents have been
implemented as mobile services that are discovered using the Jini Lookup
mechanism and used by other services for task management and communication.
Agents provide proxies for interaction with other services as well as specific
GUI to monitor and control the agent activity. Thus agents acting on behalf of
one service cooperate with other services to carry out a job, providing
inter-operation of loosely coupled services in a semi-autonomous way. Remote
file system access functionality has been incorporated by the agent framework
and allows services to dynamically share and browse the file system resources
of hosts, running the services. Generic database access functionality has been
implemented in the mobile agent framework that allows performing complex data
mining and processing operations efficiently in distributed system. A basic
data searching agent is also implemented that performs a query based search in
a file system. The testing of the framework was carried out on WAN by moving
Connectivity Test agents between AgentStations in CERN, Switzerland and NUST,
Pakistan.Comment: 7 pages, 4 figures, CHEP03, La Jolla, California, March 24-28, 200
A general purpose programming framework for ubiquitous computing environments
It is important to note that the need to support ad-hoc and potentially mobile arrangements of devices in ubiquitous environments does not fit well within the traditional client/server architecture. We believe peer-to-peer communication offers a preferable alternative due to its decentralised nature, removing dependence on individual nodes. However, this choice adds to the complexity of the developers task. In this paper, we describe a two-tiered approach to address this problem: A lower tier employing peer-to-peer interactions for managing the network infrastructure and an upper tier providing a mobile agent based programming framework. The result is a general purpose framework for developing ubiquitous applications and services, where the underlying complexity is hidden from the developer. This paper discusses our on-going work; presenting our design decisions, features supported by our framework, and some of the challenges still to be addressed in a complex programming environment
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