2,000 research outputs found

    An Infrastructure for the Dynamic Distribution of Web Applications and Services

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    This paper presents the design and implementation of an infrastructure that enables any Web application, regardless of its current state, to be stopped and uninstalled from a particular server, transferred to a new server, then installed, loaded, and resumed, with all these events occurring "on the fly" and totally transparent to clients. Such functionalities allow entire applications to fluidly move from server to server, reducing the overhead required to administer the system, and increasing its performance in a number of ways: (1) Dynamic replication of new instances of applications to several servers to raise throughput for scalability purposes, (2) Moving applications to servers to achieve load balancing or other resource management goals, (3) Caching entire applications on servers located closer to clients.National Science Foundation (9986397

    An Evaluation of Contingency Construction Methods Using Value Focused Thinking

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    Rapid Engineering Deployable, Heavy Operational Repair Squadron, Engineer (RED HORSE) Squadrons are 400-person, self-contained, combat engineer units that provide deployable and flexible expert construction capability for the United States Air Force. To help meet Air Force mission requirements, RED HORSE units currently employ a variety of traditional and innovative construction methods. But their alternatives-focused decision analysis approach to method selection limits their decision to known alternatives and may not fully achieve all of their objectives. This research developed a generic value-focused thinking (VFT) decision analysis model to help RED HORSE evaluate and select contingency construction methods. Eight alternatives were generated and evaluated using the model, and Royal Building System\u27s stay-in-place plastic formwork method achieved the highest total value score for the weights assigned to the value hierarchy. Deterministic and sensitivity analysis were performed on the value model results, and conclusions and recommendations were discussed. This research showed that VFT is a viable methodology for contingency construction method selection. The value model captured RED HORSE objectives and used their values as the basis for evaluating multiple construction method alternatives. The alternatives\u27 value score ranking results were objective, defendable, and repeatable, and the value model is highly adaptable for future contingency implementation

    Toward Customizable Multi-tenant SaaS Applications

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    abstract: Nowadays, Computing is so pervasive that it has become indeed the 5th utility (after water, electricity, gas, telephony) as Leonard Kleinrock once envisioned. Evolved from utility computing, cloud computing has emerged as a computing infrastructure that enables rapid delivery of computing resources as a utility in a dynamically scalable, virtualized manner. However, the current industrial cloud computing implementations promote segregation among different cloud providers, which leads to user lockdown because of prohibitive migration cost. On the other hand, Service-Orented Computing (SOC) including service-oriented architecture (SOA) and Web Services (WS) promote standardization and openness with its enabling standards and communication protocols. This thesis proposes a Service-Oriented Cloud Computing Architecture by combining the best attributes of the two paradigms to promote an open, interoperable environment for cloud computing development. Mutil-tenancy SaaS applicantions built on top of SOCCA have more flexibility and are not locked down by a certain platform. Tenants residing on a multi-tenant application appear to be the sole owner of the application and not aware of the existence of others. A multi-tenant SaaS application accommodates each tenant’s unique requirements by allowing tenant-level customization. A complex SaaS application that supports hundreds, even thousands of tenants could have hundreds of customization points with each of them providing multiple options, and this could result in a huge number of ways to customize the application. This dissertation also proposes innovative customization approaches, which studies similar tenants’ customization choices and each individual users behaviors, then provides guided semi-automated customization process for the future tenants. A semi-automated customization process could enable tenants to quickly implement the customization that best suits their business needs.Dissertation/ThesisDoctoral Dissertation Computer Science 201

    Deployment and Operation of Complex Software in Heterogeneous Execution Environments

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    This open access book provides an overview of the work developed within the SODALITE project, which aims at facilitating the deployment and operation of distributed software on top of heterogeneous infrastructures, including cloud, HPC and edge resources. The experts participating in the project describe how SODALITE works and how it can be exploited by end users. While multiple languages and tools are available in the literature to support DevOps teams in the automation of deployment and operation steps, still these activities require specific know-how and skills that cannot be found in average teams. The SODALITE framework tackles this problem by offering modelling and smart editing features to allow those we call Application Ops Experts to work without knowing low level details about the adopted, potentially heterogeneous, infrastructures. The framework offers also mechanisms to verify the quality of the defined models, generate the corresponding executable infrastructural code, automatically wrap application components within proper execution containers, orchestrate all activities concerned with deployment and operation of all system components, and support on-the-fly self-adaptation and refactoring

    Solutions for wireless internet connectivity in remote and rural areas

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    Abstract. These days internet connectivity is listed in the basic needs of human habitat. Internet provides inevitable support in getting knowledge, professional and social connectivity, entertainment media, and in running majority of businesses. Human dependency on internet for efficient, proficient and time saving work has increased the demand of internet connectivity worldwide. The global index shows a percentage increase in internet users from 16% to 48% (of the world population) from 2005 to 2019. The users are accessing internet via different media, inclusive of fixed lines and wireless connectivity. In wireless connectivity by 2019, 86% of the world population is using mobile broadband services offered by different telecom operators in different regions. Around 44.7% of the world population lives in rural areas as projected in 2018. Telecom operators are now seeking to cover all urban and rural, segregated, and dense, plateaus and hills, small and big geographical areas for internet connectivity. The majority of challenges faced by operators for deployment of internet connectivity services are in rural areas. Internet users cited in rural areas experience poor coverage and bad quality of service (QoS) in wireless internet access. This thesis covers the rural area internet connectivity challenges, existing deployable solutions against the challenges, and provides example solutions to overcome these challenges, to provide wireless network coverage in rural areas of Finland. Many of the existing wireless communication services are directly deployable or adjustable to the remote or rural areas almost the same way as for the urban areas. The major challenge is the low annual revenue per unit and segregated population densities of rural areas, which increase the return of investment time of network service providers. There are other challenges like ease of assembly, technology, backhaul connectivity, and electricity discussed in the thesis. The possible wireless network solutions deployable for wide area network regions and local area network regions are presented in this thesis. Thesis presents all emerging wireless technologies like small cell base station, super tower, balloon Loon project, power line Airgig project, satellite Viasat service, fixed wireless internet, and signal booster. Two possible network solutions for wireless network coverage in rural areas of Finland are analysed in the thesis. Huawei’s RuralStar small cell base station is presented as the first network solution from the viewpoint of network service provider. Hajakaista network services to individual user are presented as the second network solution from the viewpoint of end user. An addition of outdoor router in Hajakaista network architecture is presented as an additional advantage of outdoor Wi-Fi service together with indoor Wi-Fi. The limitations of the network solutions and future work scope are discussed in the discussion part of the thesis.Langattomia tietoliikenneratkaisuja syrjäalueille. Tiivistelmä. Nykyisin internetyhteys nähdään perustarpeeksi koska se antaa pääsyn tietoon, mahdollistaa ammatilliset ja sosiaaliset yhteydet sekä toimii viihdeväylänä ja tärkeänä osana liiketoimintaa. Tämän vuoksi tarve internetyhteydelle on kasvanut maailmanlaajuisesti. Vuonna 2005 maailman ihmisistä 16 % oli yhteys internettiin ja 2019 48 %. Internetyhteys voidaan saada usealla eri tavalla kuten valokuidulla ja langatonta yhteyttä käyttäen. Vuonna 2019 maailman ihmisistä 86 % käytti langatonta tekniikkaa. Vuonna 2018 44,7 % ihmisistä asui maaseutualueilla. Teleoperaattorit yrittävät kattaa kaikki kaupunki- ja maaseutualueet; eristyneet, tasaiset, kukkulaiset, isot ja pienet maantieteelliset alueet. Suurimmat haasteet ovat maaseudulla, jossa ihmiset kokevat huonoa yhteyspeittoa ja yhteyden laatua. Tämä diplomityö tarkastelee, miten nykyisiä langattomia järjestelmiä voitaisiin käyttää maaseudulla toimivien yhteyksien luomiseksi. Työ esittää kaksi esimerkkiratkaisua Suomen olosuhteisiin. Monet nykyisin kaupungeissa käytettävät ratkaisut ovat suoraan tai lähes suoraan sovellettavissa maaseudulle. Päähaasteet ovat matala vuosittainen yksikkötuotto ja hajallaan olevat alueet, jotka syyt kasvattavat investoinnin kuoletusaikaa. Muita haasteita ovat asennus, teknologia, siirtoyhteydet (tukiasemasta verkkoon) ja sähkön saanti, joita tarkastellaan työssä. Mahdollisia langattomia ratkaisuja ovat laajan alueen ja paikalliset ratkaisut, kuten työssä tuodaan esille. Työ tarkastelee solukkoverkkoja, supertornia, palloprojekti Loonia, sähkölinjoihin pohjautuvaa Airgig-projektia, Viasat-satelliittiratkaisua, kiinteää solukkoyhteyttä ja signaalin passiivista vahvistamista. Työ esittää kaksi ratkaisumallia Suomen olosuhteisiin. Toinen perustuu Huawein RuralStar-kevyttukiasemaan, jolla voi jatkaa operaattorin verkkoa. Toinen ratkaisu on kuluttajalähtöinen ja se perustuu Hajakaista Oy:n ratkaisuun. Siinä lisätään Hajakaista Oy:n perusratkaisun eli talon sisäisen Wi-Fi-verkon rinnalle ulkoinen Wi-Fi-verkko. Ratkaisujen rajoitteita tarkastellaan työn keskusteluosuudessa

    MicroFog: A Framework for Scalable Placement of Microservices-based IoT Applications in Federated Fog Environments

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    MicroService Architecture (MSA) is gaining rapid popularity for developing large-scale IoT applications for deployment within distributed and resource-constrained Fog computing environments. As a cloud-native application architecture, the true power of microservices comes from their loosely coupled, independently deployable and scalable nature, enabling distributed placement and dynamic composition across federated Fog and Cloud clusters. Thus, it is necessary to develop novel microservice placement algorithms that utilise these microservice characteristics to improve the performance of the applications. However, existing Fog computing frameworks lack support for integrating such placement policies due to their shortcomings in multiple areas, including MSA application placement and deployment across multi-fog multi-cloud environments, dynamic microservice composition across multiple distributed clusters, scalability of the framework, support for deploying heterogeneous microservice applications, etc. To this end, we design and implement MicroFog, a Fog computing framework providing a scalable, easy-to-configure control engine that executes placement algorithms and deploys applications across federated Fog environments. Furthermore, MicroFog provides a sufficient abstraction over container orchestration and dynamic microservice composition. The framework is evaluated using multiple use cases. The results demonstrate that MicroFog is a scalable, extensible and easy-to-configure framework that can integrate and evaluate novel placement policies for deploying microservice-based applications within multi-fog multi-cloud environments. We integrate multiple microservice placement policies to demonstrate MicroFog's ability to support horizontally scaled placement, thus reducing the application service response time up to 54%

    Concept design and alternate arrangements of orbiter mid-deck habitability features

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    The evaluations and recommendations for habitability features in the space shuttle orbiter mid-deck are summarized. The orbiter mission plans, the mid-deck dimensions and baseline arrangements along with crew compliments and typical activities were defined. Female and male anthropometric data based on zero-g operations were also defined. Evaluations of baseline and alternate feasible concepts provided several recommendations which are discussed
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