3,469 research outputs found
Active Coordination in Ad Hoc Networks
The increasing ubiquity of mobile devices has led to an explosion in the development of applications tailored to the particular needs of individual users. As the research community gains experience in the development of these applications, the need for middleware to simplify such software development is rapidly expanding. Vastly diļ¬erent needs of these various applications, however, have led to the emergence of many diļ¬erent middleware models, each of which approaches the dissemination of contextual information in a distinct way. The EgoSpaces model consists of logically mobile agents that operate over physically mobile hosts. EgoSpaces addresses the speciļ¬c needs of individual agents, allowing them to deļ¬ne what data is to be included in their operating context by means of declarative speciļ¬cations constraining properties of the data items, the agents that own the data, the hosts on which those agents are running, and attributes of the ad hoc network. In the resulting coordination model, agents interact with a dynamically changing environment through a set of views, custom deļ¬ned projections of the set of data objects present in the surrounding ad hoc network. This paper builds on EgoSpaces by allowing agents to assign automatic behaviors to the agent-deļ¬ned views. Behaviors consist of actions which are automatically performed in response to speciļ¬ed changes in the view. Behaviors discussed in this paper encompass reactive programming, transparent data migration, automatic data duplication, and event capture. Formal semantic deļ¬nitions and programming examples are given for each behavior
Using EgoSpaces for Scalable, Proactive Coordination in Ad Hoc Networks **PLEASE SEE WUCSE-03-11**
The increasing ubiquity of mobile devices has led to an explosion in the development of applications tailored to the particular needs of individual users. As the research community gains experience in the development of these applications, the need for middleware to simplify such software development is rapidly expanding. Vastly diļ¬erent needs of these various applications, however, have led to the emergence of many diļ¬erent middleware models, each of which approaches the dissemination of contextual information in a distinct way. The EgoSpaces model consists of logically mobile agents that operate over physically mobile hosts. EgoSpaces addresses the speciļ¬c needs of individual agents, allowing them to deļ¬ne what data is to be included in their operating context by means of declarative speciļ¬cations constraining properties of the data items, the agents that own the data, the hosts on which those agents are running, and attributes of the ad hoc network. The resulting model is one in which agents interact with a dynamically changing environment through a set of views, custom deļ¬ned projections of the set of data objects present in the surrounding ad hoc network. This paper builds on EgoSpaces by allowing agents to assign automatic behaviors to the agent-deļ¬ned views. Behaviors consist of actions which are automatically performed in response to speciļ¬ed changes in the view. Behaviors discussed in this paper encompass reactive programming, transparent data migration, automatic data duplication, and event capture. Formal semantic deļ¬nitions are given for each behavior. Since performance is a real concern in the ad hoc environment, this paper also presents protocol implementations tailored to each behavior type
Context Aware Computing for The Internet of Things: A Survey
As we are moving towards the Internet of Things (IoT), the number of sensors
deployed around the world is growing at a rapid pace. Market research has shown
a significant growth of sensor deployments over the past decade and has
predicted a significant increment of the growth rate in the future. These
sensors continuously generate enormous amounts of data. However, in order to
add value to raw sensor data we need to understand it. Collection, modelling,
reasoning, and distribution of context in relation to sensor data plays
critical role in this challenge. Context-aware computing has proven to be
successful in understanding sensor data. In this paper, we survey context
awareness from an IoT perspective. We present the necessary background by
introducing the IoT paradigm and context-aware fundamentals at the beginning.
Then we provide an in-depth analysis of context life cycle. We evaluate a
subset of projects (50) which represent the majority of research and commercial
solutions proposed in the field of context-aware computing conducted over the
last decade (2001-2011) based on our own taxonomy. Finally, based on our
evaluation, we highlight the lessons to be learnt from the past and some
possible directions for future research. The survey addresses a broad range of
techniques, methods, models, functionalities, systems, applications, and
middleware solutions related to context awareness and IoT. Our goal is not only
to analyse, compare and consolidate past research work but also to appreciate
their findings and discuss their applicability towards the IoT.Comment: IEEE Communications Surveys & Tutorials Journal, 201
LUNES: Agent-based Simulation of P2P Systems (Extended Version)
We present LUNES, an agent-based Large Unstructured NEtwork Simulator, which
allows to simulate complex networks composed of a high number of nodes. LUNES
is modular, since it splits the three phases of network topology creation,
protocol simulation and performance evaluation. This permits to easily
integrate external software tools into the main software architecture. The
simulation of the interaction protocols among network nodes is performed via a
simulation middleware that supports both the sequential and the
parallel/distributed simulation approaches. In the latter case, a specific
mechanism for the communication overhead-reduction is used; this guarantees
high levels of performance and scalability. To demonstrate the efficiency of
LUNES, we test the simulator with gossip protocols executed on top of networks
(representing peer-to-peer overlays), generated with different topologies.
Results demonstrate the effectiveness of the proposed approach.Comment: Proceedings of the International Workshop on Modeling and Simulation
of Peer-to-Peer Architectures and Systems (MOSPAS 2011). As part of the 2011
International Conference on High Performance Computing and Simulation (HPCS
2011
The Quest for Scalability and Accuracy in the Simulation of the Internet of Things: an Approach based on Multi-Level Simulation
This paper presents a methodology for simulating the Internet of Things (IoT)
using multi-level simulation models. With respect to conventional simulators,
this approach allows us to tune the level of detail of different parts of the
model without compromising the scalability of the simulation. As a use case, we
have developed a two-level simulator to study the deployment of smart services
over rural territories. The higher level is base on a coarse grained,
agent-based adaptive parallel and distributed simulator. When needed, this
simulator spawns OMNeT++ model instances to evaluate in more detail the issues
concerned with wireless communications in restricted areas of the simulated
world. The performance evaluation confirms the viability of multi-level
simulations for IoT environments.Comment: Proceedings of the IEEE/ACM International Symposium on Distributed
Simulation and Real Time Applications (DS-RT 2017
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