3,008 research outputs found
Reliable and timely event notification for publish/subscribe services over the internet
The publish/subscribe paradigm is gaining attention for the development of several applications in wide area networks (WANs) due to its intrinsic time, space, and synchronization decoupling properties that meet the scalability and asynchrony requirements of those applications. However, while the communication in a WAN may be affected by the unpredictable behavior of the network, with messages that can be dropped or delayed, existing publish/subscribe solutions pay just a little attention to addressing these issues. On the contrary, applications such as business intelligence, critical infrastructures, and financial services require delivery guarantees with strict temporal deadlines. In this paper, we propose a framework that enforces both reliability and timeliness for publish/subscribe services over WAN. Specifically, we combine two different approaches: gossiping, to retrieve missing packets in case of incomplete information, and network coding, to reduce the number of retransmissions and, consequently, the latency. We provide an analytical model that describes the information recovery capabilities of our algorithm and a simulation-based study, taking into account a real workload from the Air Traffic Control domain, which evidences how the proposed solution is able to ensure reliable event notification over a WAN within a reasonable bounded time window. © 2013 IEEE
The age of information in gossip networks
We introduce models of gossip based communication networks in which each node
is simultaneously a sensor, a relay and a user of information. We model the
status of ages of information between nodes as a discrete time Markov chain. In
this setting a gossip transmission policy is a decision made at each node
regarding what type of information to relay at any given time (if any). When
transmission policies are based on random decisions, we are able to analyze the
age of information in certain illustrative structured examples either by means
of an explicit analysis, an algorithm or asymptotic approximations. Our key
contribution is presenting this class of models.Comment: 15 pages, 8 figure
GOSSIPKIT: A Unified Component Framework for Gossip
International audienceAlthough the principles of gossip protocols are relatively easy to grasp, their variety can make their design and evaluation highly time consuming. This problem is compounded by the lack of a unified programming framework for gossip, which means developers cannot easily reuse, compose, or adapt existing solutions to fit their needs, and have limited opportunities to share knowledge and ideas. In this paper, we consider how component frameworks, which have been widely applied to implement middleware solutions, can facilitate the development of gossip-based systems in a way that is both generic and simple. We show how such an approach can maximise code reuse, simplify the implementation of gossip protocols, and facilitate dynamic evolution and re-deployment
Ordering, timeliness and reliability for publish/subscribe systems over WAN
In the last few years, the increasing use of the Internet and geo-political, sociological and financial changes induced by globalization, are paving the way for a connected world where the information is always available at the right place and the right time. As such, applications previously deployed for ``closed'' environmets, are now federating into geographically distributed systems connected through a Wide Area Network (WAN). By this evolution, in the near future no system will be isolated: every system will be composed by interconnected systems, i.e., it will be a System of Systems (SoS). Example of SoS are the Large-scale Complex Critical Infrastructure (LCCIs), such as power grids, transport infrastructures (airports and seaports), financial infrastructures, next generation intelligence platforms, to cite a few. In these systems, multiple sources of information generate a high volume of events that need to be delivered to all intended destinations by respecting several Quality of Service (QoS) constraints imposed by the critical nature of LCCIs. As such, particular attention is devoted to the middleware solution used to disseminate information in the SoS. Due to its inherently scalability provided by space, time and synchronization decoupling properties, the publish/subscribe paradigm is becoming attractive for the implementation of a middleware service for LCCIs. However, scalability is not the only requirement exhibited by SoS. Several services need to control a broader set of QoS requirements, such as timeliness, ordering and reliability. Unfortunately, current middleware solutions do not address QoS constraints required by SoS. Current publish/subscribe middleware solutions for the WAN environment offer only a best effort event dissemination, with no additional control on QoS. Just a few implementations try to address some isolated QoS policy, making them not suitable for a SoS scenario. The contribution of this thesis is to devise a QoS layer that can be posed on top of a generic publish/subscribe middleware that enriches its service by addressing: (i) ordering, (ii) reliability and (iii) timeliness in event dissemination in SoS over WAN. Specifically, we first analyze several real case studies, by highlighting their QoS requirements in terms of ordering, reliability and timeliness, and compare these requirements with both current research prototypes and commercial systems. Then, we fill the gap by proposing novel algorithms to address those requirements. The proposed protocols can also be combined together in order to provide the QoS level required by the particular application. In this way, QoS issues do not need to be addressed at application level, so as to leave applications to implement just their native functionalities
Ordering, timeliness and reliability for publish/subscribe systems over WAN
In the last few years, the increasing use of the Internet and geo-political, sociological and financial changes induced by globalization, are paving the way for a connected world where the information is always available at the right place and the right time. As such, applications previously deployed for ``closed'' environmets, are now federating into geographically distributed systems connected through a Wide Area Network (WAN). By this evolution, in the near future no system will be isolated: every system will be composed by interconnected systems, i.e., it will be a System of Systems (SoS). Example of SoS are the Large-scale Complex Critical Infrastructure (LCCIs), such as power grids, transport infrastructures (airports and seaports), financial infrastructures, next generation intelligence platforms, to cite a few. In these systems, multiple sources of information generate a high volume of events that need to be delivered to all intended destinations by respecting several Quality of Service (QoS) constraints imposed by the critical nature of LCCIs. As such, particular attention is devoted to the middleware solution used to disseminate information in the SoS. Due to its inherently scalability provided by space, time and synchronization decoupling properties, the publish/subscribe paradigm is becoming attractive for the implementation of a middleware service for LCCIs. However, scalability is not the only requirement exhibited by SoS. Several services need to control a broader set of QoS requirements, such as timeliness, ordering and reliability. Unfortunately, current middleware solutions do not address QoS constraints required by SoS. Current publish/subscribe middleware solutions for the WAN environment offer only a best effort event dissemination, with no additional control on QoS. Just a few implementations try to address some isolated QoS policy, making them not suitable for a SoS scenario. The contribution of this thesis is to devise a QoS layer that can be posed on top of a generic publish/subscribe middleware that enriches its service by addressing: (i) ordering, (ii) reliability and (iii) timeliness in event dissemination in SoS over WAN. Specifically, we first analyze several real case studies, by highlighting their QoS requirements in terms of ordering, reliability and timeliness, and compare these requirements with both current research prototypes and commercial systems. Then, we fill the gap by proposing novel algorithms to address those requirements. The proposed protocols can also be combined together in order to provide the QoS level required by the particular application. In this way, QoS issues do not need to be addressed at application level, so as to leave applications to implement just their native functionalities
Multi-Party Set Reconciliation Using Characteristic Polynomials
In the standard set reconciliation problem, there are two parties and
, each respectively holding a set of elements and . The goal is
for both parties to obtain the union . In many distributed
computing settings the sets may be large but the set difference
is small. In these cases one aims to achieve
reconciliation efficiently in terms of communication; ideally, the
communication should depend on the size of the set difference, and not on the
size of the sets.
Recent work has considered generalizations of the reconciliation problem to
multi-party settings, using a framework based on a specific type of linear
sketch called an Invertible Bloom Lookup Table. Here, we consider multi-party
set reconciliation using the alternative framework of characteristic
polynomials, which have previously been used for efficient pairwise set
reconciliation protocols, and compare their performance with Invertible Bloom
Lookup Tables for these problems.Comment: 6 page
A logic for model-checking of mean-field models
Recently, many systems consisting of a large number of interacting objects were analysed using the mean-field method, which has only been used for performance evaluation. In this short paper, we apply it to model checking. We define logic, which allows to describe the overall properties of the large system
Decentralized data fusion and data harvesting framework for heterogeneous dynamic network systems
Diese Dissertation behandelt das Thema der dezentralisieren Sammlung und
Fusion von Daten in heterogenen, ressourcenbeschraekten und dynamischen
Netzwerkszenarien.
Dazu wird ein generisches Framework vorgestellt, dass
es erlaubt die Datensammlung, den Datenaustausch und auch die Datenfusion
dynamisch zu konfigurieren. Im Zuge dessen wird auch eine Methode zur
gerichteten Fusion von Daten auf graphentheoretischer Basis eingefrt, die
es erlaubt eine logische Struktur fuer die Fusion von Informationen zu
modellieren. Eine Markup-Sprache, die sowohl menschen- als auch
maschinenlesbar ist, erlaubt es diese Struktur leicht zu editieren.
Im
Bereich der Protokolle zum Datenaustausch liegt der Fokus dieser Arbeit auf
Energieeffizienz, um auch ressourcenbeschraenkte Geraete einzubinden. Ein
weiterer Schwerpunkt liegt auf Robustheit fuer die betrachteten dynamischen
Szenarien.
Diese Dissertation schlaet zudem Design-Richtlinien vor, um
verschiedene Ziele fuer unterschiedliche Applikationen umzusetzen. Diese
lassen sich leicht in das vorgestellte Framework integrieren und darueber
konfigurieren. Dadurch ergibt sich im Ganzen eine flexible Architektur, die
sich leicht an dynamische Umgebungen anpassen laesst.With the increasing number of available smart phones, sensor nodes, and
novel mobile smart devices such as Google glass, a large volume of data
reflecting the environment is generated in the form of sensing data sources
(such as GPS, received signal strength identification, accelerometer,
microphone, images, videos and gyroscope, etc.). Some context-aware and
data centric applications require the online processing of the data
collected. The thesis researches on the decentralized data fusion and data
harvesting framework for heterogeneous dynamic network system consisting of
various devices with resource constraints. In order to achieve the flexible
design, a general architecture is provided while the detailed data fusion
and data exchange functions can be dynamically configured. A novel method
to use directed fusion graph to model the logical structure of the
distributed information fusion architecture is introduced. This directed
fusion graph can accurately portray the interconnection among different
data fusion components and the data exchange protocols, as well as the
detailed data streams. The directed fusion graph is then transformed into a
format with marked language, so that both human and machine can easily
understand and edit. In the field of data exchange protocols, this thesis
targets energy-efficiency considering the resource constraints of the
devices and robustness, as the dynamic environment might cause failures to
the system. It proposes a refined gossip strategy to reduce retransmission
of redundant data. The thesis also suggests a design guideline to achieve
different design aims for different applications. These results in this
field can be integrated into the framework effortlessly. The configuration
mechanism is another feature of this framework. Different from other
research work which consider configuration as a post-design work separated
from the main design of any middle-ware. This thesis considers the
configuration part as another dimension of the framework. The whole
strategy in configuration sets up the foundation for the flexible
architecture, and makes it easy to adapt to the dynamic environment. The
contributions in the above fields lead to a light-weight data fusion and
data harvesting framework which can be deployed easily above wireless
based, heterogeneous, dynamic network systems, even in extreme conditions,
to handle data-centric applications
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