275 research outputs found
A Taxonomy of Self-configuring Service Discovery Systems
We analyze the fundamental concepts and issues in service
discovery. This analysis places service discovery in the context of distributed
systems by describing service discovery as a third generation
naming system. We also describe the essential architectures and the
functionalities in service discovery. We then proceed to show how service
discovery fits into a system, by characterizing operational aspects.
Subsequently, we describe how existing state of the art performs service
discovery, in relation to the operational aspects and functionalities, and
identify areas for improvement
Enabling Multi-Hop Remote Method Invocation in Device-To-Device Networks
To avoid shrinking down the performance and preserve energy, low-end mobile devices can collaborate with the nearby ones by offloading computation intensive code. However, despite the long research history, code offloading is dilatory and unfit for applications that require rapidly consecutive requests per short period. Even though Remote Procedure Call (RPC) is apparently one possible approach that can address this problem, the RPC-based or message queue-based techniques are obsolete or unwieldy for mobile platforms. Moreover, the need of accessibility beyond the limit reach of the device-to-device (D2D) networks originates another problem. This article introduces a new software framework to overcome these shortcomings by enabling routing RPC architecture on multiple group device-to-device networks. Our framework provides annotations for declaring distribution decision and out-of-box components that enable peer-to-peer offloading, even when a client app and the service provider do not have a direct network link or Internet connectivity. This article also discusses the two typical mobile applications that built on top of the framework for chatting and remote browsing services, as well as the empirical experiments with actual test-bed devices to unveil the low overhead conduct and similar performance as RPC in reality
Universal Mobile Service Execution Framework for Device-To-Device Collaborations
There are high demands of effective and high-performance of collaborations between mobile devices in the places where traditional Internet connections are unavailable, unreliable, or significantly overburdened, such as on a battlefield, disaster zones, isolated rural areas, or crowded public venues. To enable collaboration among the devices in opportunistic networks, code offloading and Remote Method Invocation are the two major mechanisms to ensure code portions of applications are successfully transmitted to and executed on the remote platforms. Although these domains are highly enjoyed in research for a decade, the limitations of multi-device connectivity, system error handling or cross platform compatibility prohibit these technologies from being broadly applied in the mobile industry.
To address the above problems, we designed and developed UMSEF - an Universal Mobile Service Execution Framework, which is an innovative and radical approach for mobile computing in opportunistic networks. Our solution is built as a component-based mobile middleware architecture that is flexible and adaptive with multiple network topologies, tolerant for network errors and compatible for multiple platforms. We provided an effective algorithm to estimate the resource availability of a device for higher performance and energy consumption and a novel platform for mobile remote method invocation based on declarative annotations over multi-group device networks. The experiments in reality exposes our approach not only achieve the better performance and energy consumption, but can be extended to large-scaled ubiquitous or IoT systems
Utilizing Object Compression for Better J2ME Remote Method Invocation in 2.5G Networks
This paper introduces two new Java 2 Platform Micro Edition (J2ME) Remote Method Invocation (RMI) packages. These packages make use of serialized object compression and encryption in order to respectively minimize the transmission time and to establish secure channels. The currently used J2ME RMI package does not provide either of these features. Our packages substantially outperform the existing Java package in the total time needed to compress, transmit, and decompress the object for General Packet Radio Service (GPRS) networks, often called 2.5G networks, even under adverse conditions. The results show that the extra time incurred to compress and decompress serialized objects is small compared to the time required to transmit the object without compression in GPRS networks. Existing RMI code for J2ME can be obliviously used with our new packages
ItsBlue: A Distributed Bluetooth-Based Framework for Intelligent Transportation Systems
Inefficiency in transportation networks is having an expanding impact, at a variety of levels. Transportation authorities expect increases in delay hours and in fuel consumption and, consequently, the total cost of congestion. Nowadays, Intelligent Transportation Systems (ITS) have become a necessity in order to alleviate the expensive consequences of the rapid demand on transportation networks. Since the middle of last century, ITS have played a significant role in road safety and comfort enhancements. However, the majority of state of the art ITS are suffering from several drawbacks, among them high deployment costs and complexity of maintenance.
Over the last decade, wireless technologies have reached a wide range of daily users. Today\u27s Mobile devices and vehicles are now heavily equipped with wireless communication technologies. Bluetooth is one of the most widely spread wireless technologies in current use. Bluetooth technology has been well studied and is broadly employed to address a variety of challenges due to its cost-effectiveness, data richness, and privacy perverseness, yet Bluetooth utilization in ITS is limited to certain applications. However, Bluetooth technology has a potential far beyond today\u27s ITS applications.
In this dissertation, we introduce itsBlue, a novel Bluetooth-based framework that can be used to provide ITS researchers and engineers with desired information. In the itsBlue framework, we utilize Bluetooth technology advantages to collect road user data from unmodified Bluetooth devices, and we extract a variety of traffic statistics and information to satisfy ITS application requirements in an efficient and cost-effective way.
The itsBlue framework consists of data collection units and a central computing unit. The itsBlue data collection unit features a compact design that allows for stationary or mobile deployment in order to extend the data collection area. Central computing units aggregate obtained road user data and extract a number of Bluetooth spatial and temporal features. Road users’ Bluetooth features are utilized in a novel way to determine traffic-related information, such as road user context, appearance time, vehicle location and direction, etc. Extracted information is provided to ITS applications to generate the desired transportation services. Applying such a passive approach involves addressing several challenges, like discovering on-board devices, filtering out data received from vehicles out of the target location, or revealing vehicle status and direction.
Traffic information provided by the itsBlue framework opens a wide to the development of a wide range of ITS applications. Hence, on top of the itsBlue framework, we develop a pack of intersection management applications that includes pedestrians’ volume and waiting times, as well as vehicle queue lengths and waiting times. Also, we develop a vehicle trajectory reconstruction application.
The itsBlue framework and applications are thoroughly evaluated by experiments and simulations. In order to evaluate our work, we develop an enhanced version of the UCBT Network Simulator 2 (NS-2). According to evaluation outcomes, itsBlue framework and applications evaluations show promising results. For instance, the evaluation results show that the itsBlue framework has the ability to reveal road user context with accuracy exceeding 95% in 25s
Context-aware multi-factor authentication
Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia InformáticaAuthentication systems, as available today, are inappropriate for the requirements of ubiquitous,
heterogeneous and large scale distributed systems. Some important limitations are: (i)
the use of weak or rigid authentication factors as principal’s identity proofs, (ii) non flexibility
to combine different authentication modes for dynamic and context-aware interaction criteria,
(iii) not being extensible models to integrate new or emergent pervasive authentication factors
and (iv) difficulty to manage the coexistence of multi-factor authentication proofs in a unified
single sign-on solution. The objective of this dissertation is the design, implementation and
experimental evaluation of a platform supporting multi-factor authentication services, as a contribution
to overcome the above limitations. The devised platform will provide a uniform and
flexible authentication base for multi-factor authentication requirements and context-aware authentication
modes for ubiquitous applications and services. The main contribution is focused
on the design and implementation of an extensible authentication framework model, integrating
classic as well as new pervasive authentication factors that can be composed for different
context-aware dynamic requirements. Flexibility criteria are addressed by the establishment of a
unified authentication back-end, supporting authentication modes as defined processes and rules
expressed in a SAML based declarative markup language. The authentication base supports an
extended single sign-on system that can be dynamically tailored for multi-factor authentication
policies, considering large scale distributed applications and according with ubiquitous interaction
needs
Context-Aware Computation Offloading for Mobile Cloud Computing: Requirements Analysis, Survey and Design Guideline
AbstractAlong with the rise of mobile handheld devices the resource demands of respective applications grow as well. However, mobile devices are still and will always be limited related to performance (e.g., computation, storage and battery life), context adaptation (e.g., intermittent connectivity, scalability and heterogeneity) and security aspects. A prominent solution to overcome these limita- tions is the so-called computation offloading, which is the focus of mobile cloud computing (MCC). However, current approaches fail to address the complexity that results from quickly and constantly changing context conditions in mobile user scenarios and hence developing effective and efficient MCC applications is still challenging. Therefore, this paper first presents a list of re- quirements for MCC applications together with a survey and classification of current solutions. Furthermore, it provides a design guideline for the selection of suitable concepts for different classes of common cloud-augmented mobile applications. Finally, it presents open issues that developers and researchers should be aware of when designing their MCC-approach
Plug-and-Participate for Limited Devices in the Field of Industrial Automation
Ausgangspunkt und gleichzeitig Motivation dieser
Arbeit ist die heutige Marktsituation: Starke Kundenbedürfnisse
nach individuellen Gütern stehen oftmals eher auf
Massenproduktion ausgerichteten Planungs- und
Automatisierungssystemen gegenüber - die Befriedigung
individueller Kundenbedürfnisse setzt aber Flexibilität und
Anpassungsfähigkeit voraus. Ziel dieser Arbeit ist es daher,
einen Beitrag zu leisten, der es Unternehmen ermöglichen soll,
auf diese individuellen Bedürfnisse flexibel reagieren zu
können. Hierbei kann es im Rahmen der Dissertation natürlich
nicht um eine Revolutionierung der gesamten Automatisierungs-
und Planungslandschaft gehen; vielmehr ist die Lösung, die der
Autor der Arbeit präsentiert, ein integraler Bestandteil eines
Automatisierungskonzeptes, das im Rahmen des PABADIS Projektes
entwickelt wurde: Während PABADIS das gesamte Spektrum von
Planung und Maschineninfrastruktur zum Inhalt hat, bezieht sich
der Kern dieser Arbeit weitestgehend auf den letztgenannten
Punkt - Maschineninfrastruktur. Ziel war es, generische
Maschinenfunktionalität in einem Netzwerk anzubieten, durch das
Fertigungsaufträge selbstständig navigieren. Als Lösung
präsentiert diese Dissertation ein Plug-and-Participate
basiertes Konzept, welches beliebige Automatisierungsfunktionen
in einer spontanen Gemeinschaft bereitstellt. Basis ist ein
generisches Interface, in dem die generellen Anforderungen
solcher ad-hoc Infrastrukturen aggregiert sind. Die
Implementierung dieses Interfaces in der PABADIS
Referenzimplementierung sowie die Gegenüberstellung der
Systemanforderungen und Systemvoraussetzungen zeigte, das
klassische Plug-and-Participate Technologien wie Jini und UPnP
aufgrund ihrer Anforderungen nicht geeignet sind -
Automatisierungsgeräte stellen oftmals nur eingeschränkte
Ressourcen bereit. Daher wurde als zweites Ergebnis neben dem
Plug-and-Participate basierten Automatisierungskonzept eine
Plug-and-Participate Technologie entwickelt - Pini - die den
Gegebenheiten der Automatisierungswelt gerecht wird und
schließlich eine Anwendung von PABADIS auf heutigen
Automatisierungsanlagen erlaubt. Grundlegende Konzepte von
Pini, die dies ermöglichen, sind die gesamte Grundarchitektur
auf Basis eines verteilten Lookup Service, die Art und Weise
der Dienstrepräsentation sowie die effiziente Nutzung der
angebotenen Dienste. Mit Pini und darauf aufbauenden Konzepten
wie PLAP ist es nun insbesondere möglich,
Automatisierungssysteme wie PABADIS auf heutigen Anlagen zu
realisieren. Das wiederum ist ein Schritt in Richtung
Kundenorientierung - solche Systeme sind mit Hinblick auf
Flexibilität und Anpassungsfähigkeit gestaltet worden, um
Kundenbedürfnissen effizient gerecht zu werden
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