Search results for "Distributed"
showing 10 items of 1260 documents
Sharing media content in social media: The challenges and opportunities of user-distributed content (UDC)
2017
The article explores the distribution of mass media content by the online audience that connects by using the different social platforms, such as Facebook, Twitter and WhatsApp. The focus is on the new and developing concept of user-distributed content (UDC). From the viewpoint of media organisations, UDC is a process by which the mass media converge with online social networks through the intentional use of social media services and platforms in an effort to expand the distribution of media content. UDC does not have a long trajectory as a study object in media studies. The study suggests that practices related to UDC can be more strongly incorporated into management and journalism in main…
Optimized secure and reliable distributed data storage scheme and performance evaluation in unattended WSNs
2013
Unattended Wireless Sensor Networks (UWSNs), characterized by the absence of real-time communication between sensors and sinks, impose sensors to retain data till the next visit of a mobile sink to off-load their data. In such networks, if a sensor is compromised, data accumulated in the sensor are exposed to attackers. In addition, by holding the secret key of the compromised sensor, attackers can also learn post-compromise data accumulated by the sensor. Furthermore, once sensors stop working due to, for instance, node crash or battery depletion, all the accumulated data will be lost. In this paper, we propose a secure and reliable data distribution scheme that addresses these challenges.…
An Efficient, Robust, and Scalable Trust Management Scheme for Unattended Wireless Sensor Networks
2012
Unattended Wireless Sensor Networks (UWSNs) are characterized by long periods of disconnected operation and fixed or irregular intervals between visits by the sink. The absence of an online trusted third party, i.e., an on-site sink, makes existing trust management schemes used in legacy wireless sensor networks not applicable to UWSNs directly. In this paper, we propose a trust management scheme for UWSNs to provide efficient, robust and scalable trust data storage. For trust data storage, we employ geographic hash table to efficiently identify data storage nodes and to significantly reduce storage cost. We demonstrate, through detailed analyses and extensive simulations, that the proposed…
Towards a layer-less network architecture — A case from Wireless Sensor Networks
2011
Ad hoc and Wireless Sensor Networks (WSNs) form a challenging domain for existing network protocols and paradigms to fit into. The traditional models conceived for wired networking and adapted for wireless and mobile environments provide an inefficient and ungraceful outcome when exercised against highly dynamic and highly mobile nature of ad hoc wireless sensor networks. Efforts are being made to tweak existing (and sometimes create from scratch) principles and models that can provide a concrete framework for such newer paradigms. The momentum of the traditional layered architecture carried over from the wired networks to infrastructure based wireless networks pushes the same approaches as…
A Note on the Local Minimum Problem in Wireless Sensor Networks
2013
The Local Minimum Problem occurs in geographic routing scenarios. In this paper two solutions to this problem for certain network topologies are proposed. By using the notion of virtual coordinates a theoretical and a practical constructions are presented. A distributed algorithm for the practical approach is proposed.
Model independent assertions for integration of heterogeneous schemas
1992
Due to the proliferation of database applications, the integration of existing databases into a distributed or federated system is one of the major challenges in responding to enterprises' information requirements. Some proposed integration techniques aim at providing database administrators (DBAs) with a view definition language they can use to build the desired integrated schema. These techniques leave to the DBA the responsibility of appropriately restructuring schema elements from existing local schemas and of solving inter-schema conflicts. This paper investigates the assertion-based approach, in which the DBA's action is limited to pointing out corresponding elements in the schemas an…
XML Enabled Metamodeling and Tools for Cooperative Information Systems
2001
The development of tools to support semantic resolution is a key issue in the design of heterogeneous interoperable information systems. This paper presents a methodology and a data model translator toolkit, called X-TIME, for the design and management of interoperable information systems. X-TIME combines a metamodelling approach and XML features to provide support for automated design of wrappers or semantic reconciliators. It is a flexible semantics oriented approach that takes into account several important characteristics of interoperable information systems, including extensibility and composability. Extensibility requires a translation scheme that can easily integrate new data models.…
Analysis and validation in design time of distributed control systems implemented by means of rule based expert systems
2005
In this paper a new analytical method for control systems validation is presented. The control system will be implemented by means of expert systems based on rule nets, which are a formalism that seeks to express an automatism in a similar way to as would make it a human being: "IF antecedents THEN consequent". But at the same time rule nets are a tool for the design, analysis and implementation of rule based systems (RBS), and consist on a mathematic-logical structure which analytically reflects the set of rules that the human expert has designed. The validation consist on the analysis of the decisive rule nets properties in design time. This properties have been studied and formalized com…
Robust control in uncertain multi-inventory systems and consensus problems
2008
Abstract We consider a continuous time linear multi–inventory system with unknown demands bounded within ellipsoids and controls bounded within polytopes. We address the problem of ∈-stabilizing the inventory since this implies some reduction of the inventory costs. The main results are certain conditions under which ∈-stabilizability is possible through a saturated linear state feedback control. The idea of this approach is similar to the consensus problem solution for a network of continuous time dynamic agents, where each agent evolves according to a first order dynamics has bounded control and it is subject to unknown but bounded disturbances. In this context, we derive conditions under…
Dynamic Ordering of Firewall Rules Using a Novel Swapping Window-based Paradigm
2016
Designing and implementing efficient firewall strategies in the age of the Internet of Things (IoT) is far from trivial. This is because, as time proceeds, an increasing number of devices will be connected, accessed and controlled on the Internet. Additionally, an ever-increasingly amount of sensitive information will be stored on various networks. A good and effi- cient firewall strategy will attempt to secure this information, and to also manage the large amount of inevitable network traffic that these devices create. The goal of this paper is to propose a framework for designing optimized firewalls for the IoT. This paper deals with two fundamental challenges/problems encountered in such…