27 research outputs found
Message from the General Chairs
REACTION 2013. 2nd International Workshop on Real-time and distributed computing in emerging applications. December 3rd, 2013, Vancouver, Canada
A practical solution for functional reconfiguration of real-time service based applications through partial schedulability
REACTION 2012. 1st International workshop on Real-time and distributed computing in emerging applications. December 4th, 2012, San Juan, Puerto Rico.Timely reconfiguration in distributed real-time
systems is a complex problem with many sides to it ranging
from system-wide concerns down to the intrinsic non-robust
nature of the specific middleware software and the used
programming techniques. In an completely open distributed
system, it is not possible to achieve time-deterministic
functional reconfiguration; the set of possible target
configurations that the system can transition to could be
extremely large threatening the temporal predictability of the
reconfiguration process. Therefore, a set of bounds and
limitations to the structure of systems and to their open nature
need to be imposed. In this paper, we present the different
sides of the problem of reconfiguration. We provide a solution
for timely reconfiguration based on reducing the solution space
of solutions of partially closed applications; we have enhanced
the logic of a middleware for distributed soft real-time
applications with the proposed technique. As a result,
applications require a limited number of schedulability tests to
search for the valid target configuration. We present some
results on the actual reduction of the configuration space
achieved by our middleware.This work has been partly supported by the iLAND project (ARTEMISJU
100026) funded by the ARTEMIS JTU Call 1 and the Spanish Ministry
of Industry (www.iland-artemis.org), ARTISTDesign NoE (IST-2007-
214373) of the EU 7th Framework Programme, and by the Spanish national
project REM4VSS (TIN 2011-28339)
Towards a Reconfiguration Service for Distributed Real-Time Java
REACTION 2012. 1st International workshop on Real-time and distributed computing in emerging applications. December 4th, 2012, San Juan, Puerto Rico.Ancient monolithic distributed systems were
attached to well-known development practices and offline
analysis. Current scenarios are more dynamic, and open,
plenty of applications and services which appear and
disappear dynamically at runtime. Likewise, these scenarios
require taking into account actions that were traditionally
addressed offline, this time in an online scenario. This paper
contributes a reconfiguration service in the context of
distributed real-time Java application as a means to include
real-time reconfiguration into next generation real-time Java
systems. The paper addresses the integration taking into
account changes required in the API and the cost of some
reconfiguration strategies.This research was partially supported by the European Commission (ARTIST2 NoE, ST-2004-004527; iLAND ARTEMIS-JU Call 1) and by the Spanish national project
REM4VSS (TIN-2011-28339)
Message from the General Chairs
REACTION 2014. 3rd International Workshop on Real-time and Distributed Computing in Emerging Applications. Rome, Italy. December 2nd, 2014.Publicad
Benchmarking communication middleware for cloud computing virtualizers
REACTION 2013. 2nd International Workshop on Real-time and distributed computing in emerging applications. December 3rd, 2013, Vancouver, Canada.Virtualization technologies typically introduce additional
overhead that is specially challenging for specific domains
such as real-time systems. One of the sources of overhead are
the additional software layers that provide parallel execution
environments which reduce the effective performance given by
the infrastructure. This work identifies the factors to be analysed
by a benchmark for performance evaluation of a virtualized
middleware. It provides the set of benchmark tests that evaluate
empirically the overhead and stability on a trendy communication
middleware, DDS (Data Distribution System for Real-Time),
which enables message transmissions via publisher-subscriber
(P/S) interactions. Two different implementations, RTI and
OpenSplice, have been analysed over a general purpose virtual
machine monitor to evaluate their behavior on a client-server
application. Obtained results have provided initial execution clues
on the performance that a virtualized communication middleware
like DDS can exhibit
A dual-band priority assignment algorithm for dynamic QoS resource management
Future high-quality consumer electronics will contain a number of applications running in a highly dynamic environment, and their execution will need to be efficiently arbitrated by the underlying platform software. The multimedia applications that currently execute in such similar contexts face frequent run-time variations in their resource demands, originated by the greedy nature of the multimedia processing itself. Changes in resource demands are triggered by numerous reasons (e.g. a switch in the input media compression format). Such situations require real-time adaptation mechanisms to adjust the system operation to the new requirements, and this must be done seamlessly to satisfy the user experience. One solution for efficiently managing application execution is to apply quality of service resource management techniques, based on assigning and enforcing resource contracts to applications. Most resource management solutions provide temporal isolation by enforcing resource assignments and avoiding any resource overruns. However, this has a clear limitation over the cost-effective resource usage. This paper presents a simple priority assignment scheme based on uniform priority bands to allow that greedy multimedia tasks incur in safe overruns that increase resource usage and do not threaten the timely execution of non-overrunning tasks. Experimental results show that the proposed priority assignment scheme in combination with a resource accounting mechanism preserves timely multimedia execution and delivery, achieves a higher cost-effective processor usage, and guarantees the execution isolation of non-overrunning tasks
Introducing the new paradigm of Social Dispersed Computing: Applications, Technologies and Challenges
[EN] If last decade viewed computational services as a utility then surely
this decade has transformed computation into a commodity. Computation
is now progressively integrated into the physical networks in
a seamless way that enables cyber-physical systems (CPS) and the
Internet of Things (IoT) meet their latency requirements. Similar to
the concept of Âżplatform as a serviceÂż or Âżsoftware as a serviceÂż, both
cloudlets and fog computing have found their own use cases. Edge
devices (that we call end or user devices for disambiguation) play the
role of personal computers, dedicated to a user and to a set of correlated
applications. In this new scenario, the boundaries between
the network node, the sensor, and the actuator are blurring, driven
primarily by the computation power of IoT nodes like single board
computers and the smartphones. The bigger data generated in this
type of networks needs clever, scalable, and possibly decentralized
computing solutions that can scale independently as required. Any
node can be seen as part of a graph, with the capacity to serve as a
computing or network router node, or both. Complex applications can
possibly be distributed over this graph or network of nodes to improve
the overall performance like the amount of data processed over time.
In this paper, we identify this new computing paradigm that we call
Social Dispersed Computing, analyzing key themes in it that includes
a new outlook on its relation to agent based applications. We architect
this new paradigm by providing supportive application examples that
include next generation electrical energy distribution networks, next
generation mobility services for transportation, and applications for
distributed analysis and identification of non-recurring traffic congestion
in cities. The paper analyzes the existing computing paradigms
(e.g., cloud, fog, edge, mobile edge, social, etc.), solving the ambiguity
of their definitions; and analyzes and discusses the relevant foundational
software technologies, the remaining challenges, and research
opportunities.Garcia Valls, MS.; Dubey, A.; Botti, V. (2018). Introducing the new paradigm of Social Dispersed Computing: Applications, Technologies and Challenges. Journal of Systems Architecture. 91:83-102. https://doi.org/10.1016/j.sysarc.2018.05.007S831029