| 1. |
- Ergawy, Amr, et al.
(författare)
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Device discovery for the PalCom pervasive middleware with eliminated cross-networks periodic heart-beat messages
- 2014
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Ingår i: Procedia Computer Science. - : Elsevier BV. - 1877-0509. ; 37, s. 64-71
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Konferensbidrag (refereegranskat)abstract
- Service discovery is central in pervasive middleware systems, built on top of the communication substrate using the more fundamental mechanisms for device discovery. In mobile pervasive systems devices come and go, and switch network frequently, demanding support for device discovery across heterogeneous networks. We present the design of a device discovery mechanism for the PalCom middleware that eliminates the need for cross-network periodic keep-alive messages while still supporting timely detection of missing devices, i.e. undiscovery. The design has been implemented and is evaluated against the simplistic approach of flooding the inter-connected networks with keep-alive messages. (C) 2014 The Authors. Published by Elsevier B.V.
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| 2. |
- Ergawy, Amr, et al.
(författare)
-
Media Abstraction Framework for the Pervasive Middleware PalCom
- 2014
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Ingår i: [Host publication title missing]. ; , s. 68-75
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Konferensbidrag (refereegranskat)abstract
- Pervasive middleware systems are important for enabling the configuration and coordination of the services provided by devices in pervasive environments. PalCom is an example of such a system that aims to enable interaction among pervasive services over heterogeneous networks. In this paper we discuss the need for providing networking-media independent messaging among pervasive devices, and identify the problem of designing a media abstraction framework for a pervasive middleware. We identify a number of design principles and features that need to be satisfied by such a framework. The most important of these principles is the separation of networking protocol aspects into abstraction representations, which are exposed in a unified format to upper layers of PalCom, and communication mechanisms which are hidden by media-specific implementations of our proposed media-abstraction framework for PalCom. Also, we explain our implementation and evaluation of that framework.
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| 3. |
- Ergawy, Amr
(författare)
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Networking Media Abstraction, Device Discovery, and Routing for the Pervasive Middleware PalCom
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- PalCom is a pervasive middleware that can be used to assemble services provided by networked devices into configurations, called assemblies, for specific use cases by the user. In this dissertation, we present the development of a networking media abstraction framework for PalCom that abstracts different network interfaces in a PalCom device to upper layers of PalCom. The media abstraction framework is documented in paper I. Over the media abstraction layer, we define a device discovery mechanism that enables a PalCom device to discover other devices on its local networks, where it has network interfaces, as well as across interconnected networks. The device discovery mechanism is documented in paper II. On top of the device discovery layer, we implemented support for distance vector routing that enables routing data among discovered devices via the least cost routes. The routing layer is documented in paper III. In the last phase of our work, we refined our device discovery mechanism for PalCom to include a distributed synchronization algorithm that two PalCom nodes can utilize to re-sync their exchanged views of the network to overcome possible loss of device discovery and undiscovery notifications over unreliable channels. The synchronization algorithm is documented in paper IV.
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| 4. |
- Ergawy, Amr, et al.
(författare)
-
Supporting Distance Vector Routing Over Device Discovery Flows in the Pervasive Middleware PalCom
- 2015
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Ingår i: Procedia Computer Science. - : Elsevier BV. - 1877-0509. ; 52, s. 145-152
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Konferensbidrag (refereegranskat)abstract
- PalCom is a pervasive middleware that enables users to combine services from different devices into assemblies, or usage scenarios. The mechanism of device discovery in PalCom builds an ad-hoc network of interconnected devices while replacing cross-network periodic keep-alive messages with timely forwarded events that notify devices about the discovery and undiscovery of each other. Moreover, the device discovery mechanism is decoupled from any specific routing decisions mechanism. In this paper, we present a design that builds on this flexibility to add distance vector routing to PalCom while inheriting the event based cross-network device discovery for updating routing tables on interacting devices. The proposed design has been implemented and evaluated against a network with links that continuously change their availability.
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| 5. |
- Ergawy, Amr, et al.
(författare)
-
Synchronizing Device Discovery on Loss of Update Messages in the Pervasive Middleware Palcom
- 2016
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Ingår i: Procedia Computer Science. - : Elsevier BV. - 1877-0509. ; 94, s. 347-352
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Tidskriftsartikel (refereegranskat)abstract
- PalCom is a pervasive middleware that enables users to combine the services on devices into useful configurations. Interconnected PalCom devices can discover, and keep track of, the existence of each other by exchanging periodic heartbeats within local networks, and once-sent device appearance/disappearance notifications across interconnected networks. This approach has the advantage of eliminating the need to forward periodic heartbeats beyond the boundaries of the local networks of their originator devices. However, when a device appearance/disappearance notification is sent only once over an unreliable channel, there is a possibility of losing that notification. As a result, the device discovery information on PalCom devices will be out-of-sync. In this paper, we present the design, model-based evaluation, and the implementation status of a solution to this synchronization problem.
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