225 research outputs found
Perpetual: Byzantine Fault Tolerance for Federated Distributed Applications
Modern distributed applications rely upon the functionality of services from multiple providers. Mission-critical services, possibly shared by multiple applications, must be replicated to guarantee correct execution and availability in spite of arbitrary (Byzantine) faults. Furthermore, shared services must enforce strict fault isolation policies to prevent cascading failures across organizational and application boundaries. Most existing protocols for Byzantine fault-tolerant execution do not support interoperability between replicated services while others provide poor fault isolation. Moreover, existing protocols place impractical limitations on application development by disallowing long-running threads of computation, asynchronous operation invocation, and asynchronous request processing. We present Perpetual, a protocol that facilitates unrestricted interoperability between replicated services while enforcing strict fault isolation criteria. Perpetual supports both asynchronous operation invocation and asynchronous request processing. Perpetual also supports long-running threads of computation, enabling Byzantine fault-tolerant execution of services that carry out active computations. We present performance evaluations demonstrating a moderate overhead due to replication
A Component-Based Approach for Securing Indoor Home Care Applications
eHealth systems have adopted recent advances on sensing technologies together with advances in information and communication technologies (ICT) in order to provide people-centered services that improve the quality of life of an increasingly elderly population. As these eHealth services are founded on the acquisition and processing of sensitive data (e.g., personal details, diagnosis, treatments and medical history), any security threat would damage the public's confidence in them. This paper proposes a solution for the design and runtime management of indoor eHealth applications with security requirements. The proposal allows applications definition customized to patient particularities, including the early detection of health deterioration and suitable reaction (events) as well as security needs. At runtime, security support is twofold. A secured component-based platform supervises applications execution and provides events management, whilst the security of the communications among application components is also guaranteed. Additionally, the proposed event management scheme adopts the fog computing paradigm to enable local event related data storage and processing, thus saving communication bandwidth when communicating with the cloud. As a proof of concept, this proposal has been validated through the monitoring of the health status in diabetic patients at a nursing home.This work was financed under project DPI2015-68602-R (MINECO/FEDER, UE), UPV/EHU under project PPG17/56 and GV/EJ under recognized research group IT914-16
A performance evaluation of mobile web services security
Abstract: It is now feasible to host basic web services on a smart phone due to the advances in wireless devices and mobile communication technologies. The market capture of mobile web services also has increased significantly, in the past years. While the applications are quite welcoming, the ability to provide secure and reliable communication in the vulnerable and volatile mobile ad-hoc topologies is vastly becoming necessary. Even though a lot of standardized security specifications like WS-Security, SAML exist for web services in the wired networks, not much has been analyzed and standardized in the wireless environments. In this paper we give our analysis of adapting some of the security standards, especially WS-Security to the cellular domain, with performance statistics. The performance latencies are obtained and analyzed while observing the performance and quality of service of our Mobile Host
DroneTrack: Cloud-Based Real-Time Object Tracking Using Unmanned Aerial Vehicles Over the Internet
Low-cost drones represent an emerging technology that opens the horizon for new smart Internet-of-Things (IoT) applications. Recent research efforts in cloud robotics are pushing for the integration of low-cost robots and drones with the cloud and the IoT. However, the performance of real-time cloud robotics systems remains a fundamental challenge that demands further investigation. In this paper, we present DroneTrack, a real-time object tracking system using a drone that follows a moving object over the Internet. The DroneTrack leverages the use of Dronemap planner (DP), a cloud-based system, for the control, communication, and management of drones over the Internet. The main contributions of this paper consist in: (1) the development and deployment of the DroneTrack, a real-time object tracking application through the DP cloud platform and (2) a comprehensive experimental study of the real-time performance of the tracking application. We note that the tracking does not imply computer vision techniques but it is rather based on the exchange of GPS locations through the cloud. Three scenarios are used for conducting various experiments with real and simulated drones. The experimental study demonstrates the effectiveness of the DroneTrack system, and a tracking accuracy of 3.5 meters in average is achieved with slow-speed moving targets.info:eu-repo/semantics/publishedVersio
Discovery and Push Notification Mechanisms for Mobile Cloud Services
Viimase viie aasta jooksul on mobiilsed seadmed nagu sĂŒlearvutid, pihuarvutid, nutitelefonid jmt. tunginud peaaegu kĂ”igisse inimeste igapĂ€evaelu tegevustesse. Samuti on pĂ”hjalik teadus- ja arendustegevus mobiilsete tehnoloogiate vallas viinud mĂ€rkimisvÀÀrsete tĂ€iustusteni riistvara, tarkvara ja andmeedastuse alal. TĂ€napĂ€eval on mobiilsed seadmed varustatud sisseehitatud sensorite, kaamera, puutetundliku ekraani, suurema hulga mĂ€luga, kuid ka tĂ”husamate energiatarbemehhanismidega. Lisaks on iOS ja Android operatsioonisĂŒsteemide vĂ€ljalaske tĂ”ttu suurenenud nii mobiilirakenduste arv kui keerukus, pakkudes arvukamalt kĂ”rgetasemelisi rakendusi.
Sarnaselt on toimunud olulised arengud ja standardiseerimisele suunatud jÔupingutused veebiteenusete valdkonnas ja elementaarsetele veebiteenuste ligipÀÀsu kasutatakse laialdaselt nutitelefonidest. See on viinud loogilise jÀrgmise sammuna veebiteenuste pakkumiseni nutitelefonidest. Telefonidest veebiteenuste pakkumise kontseptsioon ei ole uus ning seda on pÔhjalikult uurinud Srirama, kes pakkus vÀlja Mobile Host (Mobiilne Veebiteenuse Pakkuja) kontseptsiooni. Algne realisatsioon kasutas aga aegunud tehnoloogiaid nagu JMEE, PersonalJava, SOAP arhitektuur jne. See töö uuendab Mobile Host'i kasutades uusimaid tehnoloogiad, nagu Android OS ja REST arhitektuur, ning pakub vÀlja teenusemootori, mis pÔhineb Apache Felix'il - OSGi platvormi realisatsioonil piiratud ressurssidega seadmetele.
HĂ€mmastava kiirusega toimunud arengud mobiilsete arvutuste vallas vĂ”imaldavad uue pĂ”lvkonna veebirakenduste loomist valdkondades nagu keskkonnateadlikkus, sotsiaalvĂ”rgustikud, koostöövahendid, asukohapĂ”hised teenused jne. Sellised rakendused saavad Ă€ra kasutada Mobile Host'i vĂ”imalusi. Selle tulemusena on klientidel ligipÀÀs vĂ€ga suurele hulgale teenustele, mistĂ”ttu tekib vajadus efektiivse teenuste avastamise mehhanismi jĂ€rele. See töö pakub vĂ€lja kataloogipĂ”hise avastusmehhanismi vĂ”rgu ĂŒlekatte toega suurtele, kĂ”rge liikuvusega vĂ”rgustikele. See mehhanism toetub OWL-S'le, mis on ontoloogia veebiteenuseid pakkuvate ressursside avastamiseks, vĂ€ljakutseks, koostamiseks ja jĂ€lgimiseks. Töö kirjeldab ka Srirama vĂ€lja pakutud algupĂ€rast teenuste avastamise mehhanismi, mis toetub peer-to-peer vĂ”rkudele ja Apache Lucene vĂ”tmesĂ”na otsingumootorile. Uurimuse kĂ€igus uuendatakse teenuseotsing kasutama Apache Solr'i, Apache Lucene'i viimast versiooni. Teenuste avastust testiti pĂ”hjalikult ja tulemused on töös kokkuvĂ”tvalt vĂ€lja toodud.
Mobiilsete tehnoloogiate vallas uuritakse ka vĂ”imalust kasutada pilvetehnolologiat laiendamaks mobiilseadmete salvestusmahtu ja töökoormust edastades pilve andme- ja arvutusmahukad ĂŒlesanded. See soodustab keerulisemate ja vĂ”imalusrohkemate mobiilirakenduste arendust. Pilve delegeeritavate toimingute aeganĂ”udva iseloomu tĂ”ttu aga on vajalik asĂŒnkroonne mehhanism teavitamaks kasutajat, millal töömahukad tegevused on lĂ”petatud. Mobiilsete pilveteenuste pakkujad ja vahevara lahendused vĂ”ivad kasu saada Mobile Host'ist ja selle asĂŒnkroonsete teavituste vĂ”imekusest. Uurimus esitleb nelja teavitusmehhanismi: AC2DM, APNS, IBM MQTT ja Mobile Host'i pĂ”hine teavitus. Töö vĂ”tab kokku kvantitatiivse analĂŒĂŒsi tulemused ja toob vĂ€lja nelja teavitamise lĂ€henemise tugevused ja nĂ”rkused. Lisaks kirjeldatakse CroudSTag rakenduse realisatsiooni - CroudSTag on mobiilirakendus, mille eesmĂ€rgiks on sotsiaalsete gruppide moodustamine kasutades nĂ€otuvastustehnoloogiat. CroudSTag-i realisatsioon kasutab mobiilseid pilveteenuseid ja Mobile Host'i, et pakkuda oma funktsionaalsust kasutajale.In the last lustrum the mobile devices such as laptops, PDAs, smart phones, tablets, etc. have pervaded almost all the environments where people perform their day-to-day activities. Further, the extensive Research and Development in mobile technologies has led to significant improvements in hardware, software and transmission. Similarly, there are significant developments and standardization efforts in web services domain and basic web services have been widely accessed from smart phones. This has lead to the logical next step of providing web services from the smart phones. The concept of the web service provisioning from smart phones is not new and has been extensively explored by Srirama who proposed the concept of Mobile Host. However, the original implementation considered aged technologies such as JMEE, PersonalJava, SOAP architecture among others. This work updates the Mobile Host to the latest technologies like Android OS and REST architecture and proposes a service engine based on Apache Felix, and OSGI implementation for resource constraint devices.
Moreover, the astonishing speed in developments in mobile computing enable the new generation of applications from domains such as context-awareness, social network, collaborative tools, location based services, etc., which benefit from the Mobile Host service provisioning capabilities. As a result the clients have access to a huge number of services available; therefore, an efficient and effective service discovery mechanism is required. The thesis proposes a directory-based with network overlay support discovery mechanism for large networks with high mobility. The proposed discovery mechanism relies in OWL-S, an ontology for service discovery, invocation, composition, and monitoring of web resources. The work also considers the original service discovery mechanism proposed by Srirama relying in peer-to-peer networks and Apache Lucene, a keyword search engine. The study updates the service search to Apache Solr, the latest development for Apache Lucene. The service discovery was extensively tested and the results are summarized in this work.
Mobile technologies are looking into the clouds for extending their capabilities in storage and processing by offloading data and process intensive tasks. This fosters the development of more complex and rich mobile applications. However, due to the time-consuming nature of the tasks delegated to the clouds, an asynchronous mechanism is necessary for notifying the user when the intensive tasks are completed. Mobile cloud service providers and Middleware solutions might benefit from Mobile Host and its asynchronous notification capabilities. The study presents four push notification mechanisms being AC2DM, APNS, IBM MQTT and Mobile Host based push notification. The work summarizes the results of a quantitative analysis and highlights the strengths and weakness of the four notifications approaches. In addition, it explains CroudSTag realization, a mobile application that aims the social group formation by means of facial recognition that relies in mobile cloud services and Mobile Host to provide its functionality to the user
Reusable and Extensible Fault Tolerance for RESTful Applications
AbstractâDespite the simplicity and scalability benefits of REST, rendering RESTful web applications fault-tolerant requires that the programmer write vast amounts of non-trivial, ad-hoc code. Network volatility, HTTP server errors, service outagesâall require custom fault handling code, whose effective implementation requires considerable programming expertise and effort. To provide a systematic and principled ap-proach to handling faults in RESTful applications, we present FT-RESTâan architectural framework for specifying fault tolerance functionality declaratively and then translating these specifications into platform-specific code. FT-REST encapsu-lates fault tolerance strategies in XML-based specifications and compiles them to modules that reify the requisite fault tolerance. To validate our approach, we have applied FT-REST to enhance several realistic RESTful applications to withstand the faults described in their FT-REST specifications. As REST is said to apply verbs (HTTP commands) to nouns (URIs), FT-REST enhances this conceptual model with adverbs that render REST reliable via reusable and extensible fault tolerance. Keywords-fault tolerance, web services, REST, software reusability, software extensibilit
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