715 research outputs found
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Knowledge Management for Public Administrations: Technical Realizations of an Enterprise Attention Management System
The improvement of governments’ efficiency has gained great importance and validity especially in the current times of economic downturn. E-Government constitutes the most contemporary techno-managerial proposition in the track of possible interventions. The paper addresses, more specifically, empowerments necessitated by Public Administration (PA) organizations. Anchored on the needs of three real-life cases, the paper describes the conception and the realization of an IT artefact together with its methodological appeals aiming at improving information access and delivery and thus PAs’ decision making capacity. Our proposition constitutes a novel approach for managing users’ attention in knowledge intensive organizations which goes beyond informing a user about changes in relevant information towards proactively supporting the user to react on changes. The approach is based on an expressive attention model, which is realized by combining ECA (Event-Condition-Action) rules with ontologies. The technical realizations described in the paper constitute the underlying infrastructure of an Enterprise Attention Management System
Security and Privacy Issues in Wireless Mesh Networks: A Survey
This book chapter identifies various security threats in wireless mesh
network (WMN). Keeping in mind the critical requirement of security and user
privacy in WMNs, this chapter provides a comprehensive overview of various
possible attacks on different layers of the communication protocol stack for
WMNs and their corresponding defense mechanisms. First, it identifies the
security vulnerabilities in the physical, link, network, transport, application
layers. Furthermore, various possible attacks on the key management protocols,
user authentication and access control protocols, and user privacy preservation
protocols are presented. After enumerating various possible attacks, the
chapter provides a detailed discussion on various existing security mechanisms
and protocols to defend against and wherever possible prevent the possible
attacks. Comparative analyses are also presented on the security schemes with
regards to the cryptographic schemes used, key management strategies deployed,
use of any trusted third party, computation and communication overhead involved
etc. The chapter then presents a brief discussion on various trust management
approaches for WMNs since trust and reputation-based schemes are increasingly
becoming popular for enforcing security in wireless networks. A number of open
problems in security and privacy issues for WMNs are subsequently discussed
before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the
author's previous submission in arXiv submission: arXiv:1102.1226. There are
some text overlaps with the previous submissio
Adapting mobile systems using logical mobility primitives
Mobile computing devices, such as personal digital assistants and mobile phones, are becoming increasingly popular, smaller, more capable and even fashionable personal items. Combined with the recent advent of wireless networking techniques, users are equipped with mobile devices of significant computational abilities, which are able to wirelessly access information by dynamically connecting to many different networks. Despite the ubiquity of mobile devices, mobile systems are built using monolithic architectures, use a small set of predefined interaction paradigms and do not exploit or adapt to the dynamicity of their local or remote context.
Applications deployed on mobile devices face considerable challenges posed by their changing surroundings. One of the main peculiarities of mobile devices is heterogeneity, which may occur in software, hardware and network protocols. Mobile systems may carry a large number of different applications, use different operating systems and middleware and, often, have more than one network interface. A further challenge is their considerable variation in the computational resources available, such as battery power, CPU speed, network bandwidth and volatile and persistent memory. Moreover, mobile computing systems are highly dynamic systems, in terms of their surroundings, implying that the requirements for applications deployed on a mobile device are a moving target. Changes in the requirements (such as integration with a new service) may require changes to the application. Consequently, these changes may mean that the application behaviour needs to adapt.
This thesis argues that the potential of the ubiquity of mobile devices cannot be realised using static and monolithic architectures, as mobile systems need to be able to adapt to accommodate changes to their environment. It investigates the use of three technologies to offer adaptation to mobile devices: Logical mobility techniques, component systems and middleware technologies. More specifically, this thesis presents the SATIN (System Adaptation Targeting Integrated Networks) component metamodel, a lightweight local component metamodel that offers the flexible use of logical mobility primitives. The metamodel is instantiated to build the SATIN middleware system, a component-based mobile computing middleware that uses the mobility primitives exported by the metamodel to reconfigure itself and applications running on top of it.
The suitability of SATIN for the creation of adaptable mobile systems is demonstrated, by using it to implement and evaluate a number of applications showing different aspects of adaptation. Moreover, existing projects are reengineered to run as SATIN components, showing the flexibility of the approach and the advantages gained over the originals
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A Cloud-based Framework for Shop Floor Big Data Management and Elastic Computing Analytics
Advanced digitalization together with the rise of disruptive Internet technologies are key enablers of a fundamental paradigm shift observed in industrial production. This is known as the fourth industrial revolution (Industry 4.0) which proposes the integration of the new generation of ICT solutions for the monitoring, adaptation, simulation, and optimisation of factories. With the democratization of sensors and actuators, factories and machine tools can now be sensorized and the data generated by these devices can be exploited, for instance, to optimise the utilization of the machines as well as their operation and maintenance. However, analyzing the vast amount of generated data is resource demanding both in terms of computing power and network bandwidth, thus requiring highly scalable solutions. This paper presents a novel big data approach and analytics framework for the management and analysis of machine generated data in the cloud. It brings together standard open source technologies and the exploitation of elastic computing, which, as a whole, can be adapted to and deployed on different cloud computing platforms. This enables reducing infrastructure costs, minimizing deployment difficulty and providing on-demand access to a virtually infinite set of computing power, storage and network resources.H202
EXPLAINING THE ROLE OF SERVICE-ORIENTED ARCHITECTURE FOR CYBER-PHYSICAL SYSTEMS BY ESTABLISHING LOGICAL LINKS
In the context of the so-called fourth industrial revolution, cyber-physical systems (CPS) build the technological foundation for the increasing digitalisation of our world. Because guidelines to overcome challenges of building such systems (e.g. security concerns, missing know-how, and lack of standards) are scarce, researchers and practitioners alike have begun to analyse the role of the mature paradigm of service-oriented architecture (SOA) in implementing CPS. However, the relationship between SOA and CPS is not entirely understood. To close this gap, we analyse SOA’s role for CPS based on a concept-driven literature review. The analysis of 12 publications that address the interrelation between SOA and CPS yielded four groups of CPS benefits that can be achieved by leveraging SOA. Combining these benefits with architectural layers and SOA’s design principles, we identify logical links that explain the role of SOA for CPS. Future research might concentrate on dominant patterns to scrutinise how a specific benefit can be achieved by leveraging SOA. Designers of CPS can leverage the identified patterns to understand the importance of specific characteristics of SOA to address the unique requirements of their CPS
Context Sensor Data on Demand for Mobile Users Supported by XMPP
Tänapäeval võimaldavad tehnoloogilised edusammud kasutaja käitumise seiremeetodites automatiseerida teatud arvutusülesandeid, mis täidetakse kasutaja kavatsust prognoosides. Nutitelefonid rikastavad mobiilseid rakendusi prognoosiva käitumisega kasutatavuses, mis võimaldab käitumismustritega sammu pidada. Üldiselt on sellist käitumist võimalik saavutada nutitelefoni enda vahenditega, kasutades telefoni sisse ehitatud mikromehaanilisi seadmeid, mis võimaldavad keskkonda tajuda. Lisaks võivad mobiilsed rakendused kasutaja mobiilse kogemuse rikastamiseks lõigata kasu keskkonda integreeritud hajuslausteenustest, nagu näiteks ümbrustundlike mängude, kodu automatiseerimise tarkvara jms puhul.
Ent mobiilikasutajatele suunatud lausteenuseid pakkuvatel elektroonilistel seadmetel, mis koguvad sensorite abi keskkonnast informatsiooni, on teatavad riistvaralised piirangud (arvutusjõudlus, mälu, salvestusmeedia, energiatarbimine jne). Seega, lausüsteemid ei ole võimelised nõudluse suurenemisel skaleeruma ega rakendama suurt arvutusjõudlust.
Töö eesmärgiks on pakkuda lahendus ületamaks skaleeruvuse, andmete terviklikkuse säilitamise ja vähese arvutusjõudluse probleeme ning rikastada nutitelefoni rakendusi detailsete kasutajapõhiste andmetega. Eesmärgi saavutamiseks transporditakse sensoritelt kogutud informatsioon optimiseeritud XMPP protokolli abiga Arduino mikrokontrollerist pilvesüsteemi. Süsteemi ehitamiseks kasutatakse Arduino poolt pakutavat odavat riistvara, samas kui pilvesüsteemi usaldusväärset ja kõrge kättesaadavusega vahendeid kasutatakse mikrokontrollerist saadetud andmete salvestamiseks ja edaspidiseks töötlemiseks.
Töö käigus testiti mikrokontrolleri energia nõudlust, kasutades 9V patareid, nii juhtme kui ka juhtmevaba liidesega. Tulemused tõestasid eeldustele vastupidiselt, et juhtmevaba süsteemi energia nõudlus on suurem. Lisaks testiti vabavara XMPP serveri jõudlust pilvesüsteemi keskkonnas ning tulemused näitasid, et XMPP võimaldab üheaegselt serveerida suure hulga kasutajaid
Effective link quality estimation as a means to improved end-to-end packet delivery in high traffic mobile ad hoc networks
Accurate link quality estimation is a fundamental building block in quality aware multi hop routing. In an inherently lossy, unreliable and dynamic medium such as wireless, the task of accurate estimation becomes very challenging. Over the years ETX has been widely used as a reliable link quality estimation metric. However, more recently it has been established that under heavy traffic loads ETX performance gets significantly worse. We examine the ETX metric's behavior in detail with respect to the MAC layer and UDP data; and identify the causes of its unreliability. Motivated by the observations made in our analysis, we present the design and implementation of our link quality measurement metric xDDR – a variation of ETX. This article extends xDDR to support network mobility. Our experiments show that xDDR substantially outperforms minimum hop count, ETX and HETX in terms of end-to-end packet delivery ratio in static as well as mobile scenarios.</p
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