184 research outputs found
Challenges for orchestration and instance selection of composite services in distributed edge clouds
Today's centralized cloud-computing infrastructures have not been designed with geo-localized, personalized, bandwidth/processing-intensive, real-time applications in mind. High network delay and low throughput can have a significant impact on the user experience. Instead, such services could be deployed in distributed service nodes at the edge of the network, closer to the user. In this paper we focus on composite services of which the components are running in different service nodes. We present a two-layer framework that provides service orchestration and instance selection. We present the orchestration mechanisms to enable the flexible re-use of components across different composite services. For the resolution layer of our framework, we present two modes of operation that combine network and service availability information for efficient per-request instance selection among a multitude of service replicas
Fault Tolerant Adaptive Parallel and Distributed Simulation through Functional Replication
This paper presents FT-GAIA, a software-based fault-tolerant parallel and
distributed simulation middleware. FT-GAIA has being designed to reliably
handle Parallel And Distributed Simulation (PADS) models, which are needed to
properly simulate and analyze complex systems arising in any kind of scientific
or engineering field. PADS takes advantage of multiple execution units run in
multicore processors, cluster of workstations or HPC systems. However, large
computing systems, such as HPC systems that include hundreds of thousands of
computing nodes, have to handle frequent failures of some components. To cope
with this issue, FT-GAIA transparently replicates simulation entities and
distributes them on multiple execution nodes. This allows the simulation to
tolerate crash-failures of computing nodes. Moreover, FT-GAIA offers some
protection against Byzantine failures, since interaction messages among the
simulated entities are replicated as well, so that the receiving entity can
identify and discard corrupted messages. Results from an analytical model and
from an experimental evaluation show that FT-GAIA provides a high degree of
fault tolerance, at the cost of a moderate increase in the computational load
of the execution units.Comment: arXiv admin note: substantial text overlap with arXiv:1606.0731
TRAMMAS: Enhancing Communication in Multiagent Systems
Tesis por compendio[EN] Over the last years, multiagent systems have been proven to be a powerful and versatile paradigm, with a big
potential when it comes to solving complex problems in dynamic and distributed environments, due to their flexible
and adaptive behavior. This potential does not only come from the individual features of agents (such as autonomy,
reactivity or reasoning power), but also to their capability to communicate, cooperate and coordinate in order to
fulfill their goals. In fact, it is this social behavior what makes multiagent systems so powerful, much more than the
individual capabilities of agents.
The social behavior of multiagent systems is usually developed by means of high
level abstractions, protocols and languages, which normally rely on (or at least, benefit from) agents being able to
communicate and interact indirectly. However, in the development process, such high level concepts habitually
become weakly supported, with mechanisms such as traditional messaging, massive broadcasting, blackboard
systems or ad hoc solutions. This lack of an appropriate way to support indirect communication in actual multiagent
systems compromises their potential.
This PhD thesis proposes the use of event tracing as a flexible, effective and efficient support for indirect interaction
and communication in multiagent systems. The main contribution of this thesis is TRAMMAS, a generic, abstract
model for event tracing support in multiagent systems. The model allows all entities in the system to share their
information as trace events, so that any other entity which require this information is able to receive it. Along with
the model, the thesis also presents an abstract architecture, which redefines the model in terms of a set of tracing
facilities that can be then easily incorporated to an actual multiagent platform. This architecture follows a
service-oriented approach, so that the tracing facilities are provided in the same way than other traditional services
offered by the platform. In this way, event tracing can be considered as an additional information provider for
entities in the multiagent system, and as such, it can be integrated from the earliest stages of the development
process.[ES] A lo largo de los últimos años, los sistemas multiagente han demostrado ser un paradigma potente y versátil,
con un gran potencial a la hora de resolver problemas complejos en entornos dinámicos y distribuidos, gracias a
su comportamiento flexible y adaptativo. Este potencial no es debido únicamente a las caracterÃsticas individuales
de los agentes (como son su autonomÃa, y su capacidades de reacción y de razonamiento), sino que también se
debe a su capacidad de comunicación y cooperación a la hora de conseguir sus objetivos. De hecho, por encima
de la capacidad individual de los agentes, es este comportamiento social el que dota de potencial a los sistemas
multiagente.
El comportamiento social de los sistemas multiagente suele desarrollarse empleando abstracciones, protocolos y
lenguajes de alto nivel, los cuales, a su vez, se basan normalmente en la capacidad para comunicarse e
interactuar de manera indirecta de los agentes (o como mÃnimo, se benefician en gran medida de dicha
capacidad). Sin embargo, en el proceso de desarrollo software, estos conceptos de alto nivel son soportados
habitualmente de manera débil, mediante mecanismos como la mensajerÃa tradicional, la difusión masiva, o el uso
de pizarras, o mediante soluciones totalmente ad hoc. Esta carencia de un soporte genérico y apropiado para la
comunicación indirecta en los sistemas multiagente reales compromete su potencial.
Esta tesis doctoral propone el uso del trazado de eventos como un soporte flexible, efectivo y eficiente para la
comunicación indirecta en sistemas multiagente. La principal contribución de esta tesis es TRAMMAS, un modelo
genérico y abstracto para dar soporte al trazado de eventos en sistemas multiagente. El modelo permite a
cualquier entidad del sistema compartir su información en forma de eventos de traza, de tal manera que cualquier
otra entidad que requiera esta información sea capaz de recibirla. Junto con el modelo, la tesis también presenta
una arquitectura {abs}{trac}{ta}, que redefine el modelo como un conjunto de funcionalidades que pueden ser
fácilmente incorporadas a una plataforma multiagente real. Esta arquitectura sigue un enfoque orientado a
servicios, de modo que las funcionalidades de traza son ofrecidas por parte de la plataforma de manera similar a
los servicios tradicionales. De esta forma, el trazado de eventos puede ser considerado como una fuente adicional
de información para las entidades del sistema multiagente y, como tal, puede integrarse en el proceso de
desarrollo software desde sus primeras etapas.[CA] Al llarg dels últims anys, els sistemes multiagent han demostrat ser un paradigma potent i versà til, amb un gran
potencial a l'hora de resoldre problemes complexes a entorns dinà mics i distribuïts, grà cies al seu comportament
flexible i adaptatiu. Aquest potencial no és només degut a les caracterÃstiques individuals dels agents (com són la
seua autonomia, i les capacitats de reacció i raonament), sinó també a la seua capacitat de comunicació i
cooperació a l'hora d'aconseguir els seus objectius. De fet, per damunt de la capacitat individual dels agents, es
aquest comportament social el que dóna potencial als sistemes multiagent.
El comportament social dels sistemes multiagent solen desenvolupar-se utilitzant abstraccions, protocols i
llenguatges d'alt nivell, els quals, al seu torn, es basen normalment a la capacitat dels agents de comunicar-se i
interactuar de manera indirecta (o com a mÃnim, es beneficien en gran mesura d'aquesta capacitat). Tanmateix, al
procés de desenvolupament software, aquests conceptes d'alt nivell son suportats habitualment d'una manera
dèbil, mitjançant mecanismes com la missatgeria tradicional, la difusió massiva o l'ús de pissarres, o mitjançant
solucions totalment ad hoc. Aquesta carència d'un suport genèric i apropiat per a la comunicació indirecta als
sistemes multiagent reals compromet el seu potencial.
Aquesta tesi doctoral proposa l'ús del traçat d'esdeveniments com un suport flexible, efectiu i eficient per a la
comunicació indirecta a sistemes multiagent. La principal contribució d'aquesta tesi és TRAMMAS, un model
genèric i abstracte per a donar suport al traçat d'esdeveniments a sistemes multiagent. El model permet a
qualsevol entitat del sistema compartir la seua informació amb la forma d'esdeveniments de traça, de tal forma que
qualsevol altra entitat que necessite aquesta informació siga capaç de rebre-la. Junt amb el model, la tesi també
presenta una arquitectura abstracta, que redefineix el model com un conjunt de funcionalitats que poden ser
fà cilment incorporades a una plataforma multiagent real. Aquesta arquitectura segueix un enfoc orientat a serveis,
de manera que les funcionalitats de traça són oferides per part de la plataforma de manera similar als serveis
tradicionals. D'aquesta manera, el traçat d'esdeveniments pot ser considerat com una font addicional d'informació
per a les entitats del sistema multiagent, i com a tal, pot integrar-se al procés de desenvolupament software des de
les seues primeres etapes.Búrdalo Rapa, LA. (2016). TRAMMAS: Enhancing Communication in Multiagent Systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61765TESISCompendi
A Taxonomy of Workflow Management Systems for Grid Computing
With the advent of Grid and application technologies, scientists and
engineers are building more and more complex applications to manage and process
large data sets, and execute scientific experiments on distributed resources.
Such application scenarios require means for composing and executing complex
workflows. Therefore, many efforts have been made towards the development of
workflow management systems for Grid computing. In this paper, we propose a
taxonomy that characterizes and classifies various approaches for building and
executing workflows on Grids. We also survey several representative Grid
workflow systems developed by various projects world-wide to demonstrate the
comprehensiveness of the taxonomy. The taxonomy not only highlights the design
and engineering similarities and differences of state-of-the-art in Grid
workflow systems, but also identifies the areas that need further research.Comment: 29 pages, 15 figure
Design and implementation of a multi-agent opportunistic grid computing platform
Opportunistic Grid Computing involves joining idle computing resources in enterprises into a converged high performance commodity infrastructure. The research described in this dissertation investigates the viability of public resource computing in offering a plethora of possibilities through seamless access to shared compute and storage resources. The research proposes and conceptualizes the Multi-Agent Opportunistic Grid (MAOG) solution in an Information and Communication Technologies for Development (ICT4D) initiative to address some limitations prevalent in traditional distributed system implementations. Proof-of-concept software components based on JADE (Java Agent Development Framework) validated Multi-Agent Systems (MAS) as an important tool for provisioning of Opportunistic Grid Computing platforms. Exploration of agent technologies within the research context identified two key components which improve access to extended computer capabilities. The first component is a Mobile Agent (MA) compute component in which a group of agents interact to pool shared processor cycles. The compute component integrates dynamic resource identification and allocation strategies by incorporating the Contract Net Protocol (CNP) and rule based reasoning concepts. The second service is a MAS based storage component realized through disk mirroring and Google file-system’s chunking with atomic append storage techniques. This research provides a candidate Opportunistic Grid Computing platform design and implementation through the use of MAS. Experiments conducted validated the design and implementation of the compute and storage services. From results, support for processing user applications; resource identification and allocation; and rule based reasoning validated the MA compute component. A MAS based file-system that implements chunking optimizations was considered to be optimum based on evaluations. The findings from the undertaken experiments also validated the functional adequacy of the implementation, and show the suitability of MAS for provisioning of robust, autonomous, and intelligent platforms. The context of this research, ICT4D, provides a solution to optimizing and increasing the utilization of computing resources that are usually idle in these contexts
On the Combination of Game-Theoretic Learning and Multi Model Adaptive Filters
This paper casts coordination of a team of robots within the framework of game theoretic learning algorithms. In particular a novel variant of fictitious play is proposed, by considering multi-model adaptive filters as a method to estimate other players’ strategies. The proposed algorithm can be used as a coordination mechanism between players when they should take decisions under uncertainty. Each player chooses an action after taking into account the actions of the other players and also the uncertainty. Uncertainty can occur either in terms of noisy observations or various types of other players. In addition, in contrast to other game-theoretic and heuristic algorithms for distributed optimisation, it is not necessary to find the optimal parameters a priori. Various parameter values can be used initially as inputs to different models. Therefore, the resulting decisions will be aggregate results of all the parameter values. Simulations are used to test the performance of the proposed methodology against other game-theoretic learning algorithms.</p
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