99 research outputs found
Unidirectional Quorum-based Cycle Planning for Efficient Resource Utilization and Fault-Tolerance
In this paper, we propose a greedy cycle direction heuristic to improve the
generalized redundancy quorum cycle technique. When applied using
only single cycles rather than the standard paired cycles, the generalized
redundancy technique has been shown to almost halve the necessary
light-trail resources in the network. Our greedy heuristic improves this
cycle-based routing technique's fault-tolerance and dependability.
For efficiency and distributed control, it is common in distributed systems
and algorithms to group nodes into intersecting sets referred to as quorum
sets. Optimal communication quorum sets forming optical cycles based on
light-trails have been shown to flexibly and efficiently route both
point-to-point and multipoint-to-multipoint traffic requests. Commonly cycle
routing techniques will use pairs of cycles to achieve both routing and
fault-tolerance, which uses substantial resources and creates the potential for
underutilization. Instead, we use a single cycle and intentionally utilize
redundancy within the quorum cycles such that every point-to-point
communication pairs occur in at least cycles. Without the paired
cycles the direction of the quorum cycles becomes critical to the fault
tolerance performance. For this we developed a greedy cycle direction heuristic
and our single fault network simulations show a reduction of missing pairs by
greater than 30%, which translates to significant improvements in fault
coverage.Comment: Computer Communication and Networks (ICCCN), 2016 25th International
Conference on. arXiv admin note: substantial text overlap with
arXiv:1608.05172, arXiv:1608.05168, arXiv:1608.0517
A Systematic Approach to Compute All Cyclic Quorum Sets
Use of quorum sets and cyclic quorum sets have proved to be a very useful method to achieve efficient initial data placement and data communication in distributed computation and communication systems. For example, in all-pairs data interaction problems, cyclic quorum sets can be used to avoid communication completely after initial data placement. Searching for all possible cyclic quorum sets for a given number of objects, P, is a task that requires massive computations. This is known to be a hard problem and no time complexity reduction method has been found thus far. In this paper, we try to optimize the search process by avoiding the search space where it is not possible to find a feasible cyclic quorum base set. By studying all possible cyclic quorum sets for given P, we develop insight into the properties of all quorum sets that helps us to reduce the total number of computations significantly compared to that adopting the naĂŻve exhaustive search. We notice that as P grows, better performance could be achieved
Efficient Passive Clustering and Gateways selection MANETs
Passive clustering does not employ control packets to collect topological information in ad hoc networks. In our proposal, we avoid making frequent changes in cluster architecture due to repeated election and re-election of cluster heads and gateways. Our primary objective has been to make Passive Clustering more practical by employing optimal number of gateways and reduce the number of rebroadcast packets
Keeping checkpoint/restart viable for exascale systems
Next-generation exascale systems, those capable of performing a quintillion operations per second, are expected to be delivered in the next 8-10 years. These systems, which will be 1,000 times faster than current systems, will be of unprecedented scale. As these systems continue to grow in size, faults will become increasingly common, even over the course of small calculations. Therefore, issues such as fault tolerance and reliability will limit application scalability. Current techniques to ensure progress across faults like checkpoint/restart, the dominant fault tolerance mechanism for the last 25 years, are increasingly problematic at the scales of future systems due to their excessive overheads. In this work, we evaluate a number of techniques to decrease the overhead of checkpoint/restart and keep this method viable for future exascale systems. More specifically, this work evaluates state-machine replication to dramatically increase the checkpoint interval (the time between successive checkpoints) and hash-based, probabilistic incremental checkpointing using graphics processing units to decrease the checkpoint commit time (the time to save one checkpoint). Using a combination of empirical analysis, modeling, and simulation, we study the costs and benefits of these approaches on a wide range of parameters. These results, which cover of number of high-performance computing capability workloads, different failure distributions, hardware mean time to failures, and I/O bandwidths, show the potential benefits of these techniques for meeting the reliability demands of future exascale platforms
Design and implementation of a secure wide-area object middleware
Tanenbaum, A.S. [Promotor]Crispo, C.B. [Copromotor
A software architecture for electro-mobility services: a milestone for sustainable remote vehicle capabilities
To face the tough competition, changing markets and technologies in automotive industry,
automakers have to be highly innovative. In the previous decades, innovations were
electronics and IT-driven, which increased exponentially the complexity of vehicleâs internal
network. Furthermore, the growing expectations and preferences of customers oblige these
manufacturers to adapt their business models and to also propose mobility-based services.
One other hand, there is also an increasing pressure from regulators to significantly reduce
the environmental footprint in transportation and mobility, down to zero in the foreseeable
future.
This dissertation investigates an architecture for communication and data exchange
within a complex and heterogeneous ecosystem. This communication takes place between
various third-party entities on one side, and between these entities and the infrastructure
on the other. The proposed solution reduces considerably the complexity of vehicle
communication and within the parties involved in the ODX life cycle. In such an
heterogeneous environment, a particular attention is paid to the protection of confidential
and private data. Confidential data here refers to the OEMâs know-how which is enclosed
in vehicle projects. The data delivered by a car during a vehicle communication session
might contain private data from customers. Our solution ensures that every entity of this
ecosystem has access only to data it has the right to. We designed our solution to be
non-technological-coupling so that it can be implemented in any platform to benefit from
the best environment suited for each task. We also proposed a data model for vehicle
projects, which improves query time during a vehicle diagnostic session. The scalability and
the backwards compatibility were also taken into account during the design phase of our
solution.
We proposed the necessary algorithms and the workflow to perform an efficient vehicle
diagnostic with considerably lower latency and substantially better complexity time and
space than current solutions. To prove the practicality of our design, we presented a
prototypical implementation of our design. Then, we analyzed the results of a series of tests
we performed on several vehicle models and projects. We also evaluated the prototype
against quality attributes in software engineering
Knowledge-Based Decision Support for Integrated Water Resources Management with an application for Wadi Shueib, Jordan
This book takes a two-staged approach to contribute to the contemporary Integrated Water Resources Management (IWRM) research. First it investigates sub-basin-scale IWRM modelling and scenario planning. The Jordanian Wadi Shueib is used as exemplary case study. Then, it develops a framework to collaboratively manage planning and decision making knowledge on the basis of semantic web technologies. Future IWRM initiatives can benefit from the valuable insights achieved in the presented study
Management, Technology and Learning for Individuals, Organisations and Society in Turbulent Environments
This book presents the collection of fifty two papers which were presented on the First International Conference on BUSINESS SUSTAINABILITY â08 - Management, Technology and Learning for Individuals, Organisations and Society in Turbulent Environments, held in Ofir, Portugal, from 25th to 27th of June, 2008. The main motive of the meeting was the growing awareness of the importance of the sustainability issue. This importance had emerged from the growing uncertainty of the market behaviour that leads to the characterization of the market, i.e. environment, as turbulent. Actually, the characterization of the environment as uncertain and turbulent reflects the fact that the traditional technocratic and/or socio-technical approaches cannot effectively and efficiently lead with the present situation. In other words, the rise of the sustainability issue means the quest for new instruments to deal with uncertainty and/or turbulence.
The sustainability issue has a complex nature and solutions are sought in a wide range of domains and instruments to achieve and manage it. The domains range from environmental sustainability (referring to natural environment) through organisational and business sustainability towards social sustainability. Concerning the instruments for sustainability, they range from traditional engineering and management methodologies towards âsoftâ instruments such as knowledge, learning, creativity. The papers in this book address virtually whole sustainability problems space in a greater or lesser extent. However, although the uncertainty and/or turbulence, or in other words the dynamic properties, come from coupling of management, technology, learning, individuals, organisations and society, meaning that everything is at the same time effect and cause, we wanted to put the emphasis on business with the intention to address primarily the companies and their businesses.
From this reason, the main title of the book is âBusiness Sustainabilityâ but with the approach of coupling Management, Technology and Learning for individuals, organisations and society in Turbulent Environments.
Concerning the First International Conference on BUSINESS SUSTAINABILITY, its particularity was that it had served primarily as a learning environment in which the papers published in this book were the ground for further individual and collective growth in understanding and perception of sustainability and capacity for building new instruments for business sustainability. In that respect, the methodology of the conference work was basically dialogical, meaning promoting dialog on the papers, but also including formal paper presentations. In this way, the conference presented a rich space for satisfying different authorsâ and participantsâ needs. Additionally, promoting the widest and global learning environment and participativeness, the Conference Organisation provided the broadcasting over Internet of the Conference sessions, dialogical and formal presentations, for all authorsâ and participantsâ institutions, as an innovative Conference feature.
In these terms, this book could also be understood as a complementary instrument to the Conference authorsâ and participantsâ, but also to the wider readershipsâ interested in the sustainability issues.
The book brought together 97 authors from 10 countries, namely from Australia, Finland, France, Germany, Ireland, Portugal, Russia, Serbia, Sweden and United Kingdom. The authors ârangedâ from senior and renowned scientists to young researchers providing a rich and learning environment.
At the end, the editors hope and would like that this book will be useful, meeting the expectation of the authors and wider readership and serving for enhancing the individual and collective learning, and to incentive further scientific development and creation of new papers.
Also, the editors would use this opportunity to announce the intention to continue with new editions of the conference and subsequent editions of accompanying books on the subject of BUSINESS SUSTAINABILITY, the second of which is planned for year 2011.info:eu-repo/semantics/publishedVersio
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