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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Developing Ultra-High Resolution 3D Printing for Microfluidics

Hooper, Kent Richard 02 August 2022 (has links)
Building upon previous research on Digital Light Projection (DLP) 3D printing for microfluidics, in this thesis I performed the detailed design and fabrication of a novel DLP 3D printer to increase resolution and device footprint flexibility. This new printer has a pixel resolution twice that of our group’s previous printers (3.8 μm vs 7.6 μm). I demonstrated a new state of the art for minimum channel width, reducing the minimum width to 15 μm wide (and 30 μm tall). This is an improvement over the previous smallest width of 20 μm. This printer also has the capacity to perform multiple spatially distinct exposures per printed layer and stitch them into one interconnected device. Image stitching enables printing devices with identical build areas to previous printers, and with smaller pixel pitch. I pursued validation of this stitching capacity by fabricating channel devices with features crossing the stitched image boundary, with the goal of printing channels that would flow fluid consistently and without leaking. To accomplish this, I began by characterizing the print parameters for successfully printing single microfluidics channels across the stitched image boundary, and then I explored the sensitivity of my method to multiple crossings of the image boundary by printing a stacked serpentine channel that crossed the stitched image boundary 392 times. This demonstrated that an arbitrary number of stitched boundary crossings are feasible and thus a high degree of complex device component integration across these boundaries is also possible. These developments will be useful in future research and design of 3D printed microfluidic devices.
32

Paslaugų kokybės heterogeniniuose bevieliuose tinkluose tyrimai / Analysis of Quality of Service in Heterogeneous Wireless Networks

Vindašius, Antanas 22 December 2010 (has links)
Disertacijoje nagrinėjama belaidės prieigos tinklų savybės, gebėjimas kontroliuoti ir užtikrinti paslaugos kokybę (QoS) bei stebėti ją vartotojų įrenginiuose. Darbo tikslas – ištirti belaidės prieigos tinklų darbo parametrų įtaką paslaugos kokybei ir sukurti apibendrintą paslaugos kokybės stebėsenos priemonių, taikomų galutinio vartotojo įrenginyje, modelį. / The dissertation investigates wireless access network performance, ability to control and enforce quality of service (QoS) and track it at user device. The objective of presented research is to investigate wireless access network performance parameter impact on quality of service and develop reference model of QoS monitor, applied for end-user device.
33

Model adaptivnog sistema za praćenje i predikciju rada distribuiranih aplikacija / Model of Adaptive System for Continuous Monitoring and Performance Prediction of Distributed Applications

Okanović Dušan 01 October 2012 (has links)
<p>Stalno praćenje rada softvera je neophodno da bi se utvrdilo da li softver po&scaron;tuje zadate nivoe kvaliteta. Na osnovu sakupljenih podataka, moguće je da se predvidi i dalje pona&scaron;anje aplikacije i da se izvr&scaron;i izbor daljih&nbsp;akcija da bi se održao zahtevani nivo. Tema ove disertacije je razvoj sistema za kontinualno praćenje performansi softvera, kao i razvoj modela za predviđanje performansi softvera. Za implementaciju sistema potrebljena je JEE tehnologija, ali je sistem razvijen tako da može da se primeni i za praćenje softvera razvijenog za druge platforme. Sistem je modelovan tako minimalno utiče na performanse sistema softvera koji se prati. Linearna regresija je upotrebljena za modelovanje zavisnosti performansi od okruženja u kom se softver izvr&scaron;ava. Sistem je upotrebljen za praćenje izabrane JEE aplikacije.</p> / <p>Continuous monitoring of software is necessary to determine whether the software performs within required service perfomance levels. Based on collected&nbsp;data, it is possible to predict the future performance of applications and to plan further actions in order to maintain the required service levels. The theme of this dissertation is the development of systems for continuous performance monitoring software, as well as the development of models for predicting the performance of software. To implement the system was used JEE technologies, but the system was developed so that it can be used for tracking software developed for other platforms. The system is modeled as a minimum impact on system performance software that is monitored. Linear regression was used for modeling the dependence of the performance environment in which the software is running. The system was used to monitor selected JEE applications.</p>
34

Physiopathologie de la sclérose latérale amyotropique : implication des systèmes neuromodulateurs dans les réseaux moteurs spinaux / Physiopathology of the amyotrophic lateral sclerosis : implication of the neuromodulatory systems in the spinal motor netwoks

Milan, Lea 10 December 2014 (has links)
Les systèmes neuromodulateurs jouent un rôle essentiel dans la mise en place et dansla régulation des réseaux moteurs spinaux afin d’adapter finement le rythme et le patronlocomoteur aux contraintes internes et externes de l’organisme. Il a été montré que desaltérations du fonctionnement de ces systèmes étaient impliquées dans de nombreusespathologies neurologiques. La sclérose latérale amyotrophique (SLA) est une maladieneurodégénérative caractérisée par la perte des neurones moteurs corticaux et spinaux. Bienque les symptômes de la SLA n’apparaissent qu’à l’âge adulte, de plus en plus d’élémentsamènent à penser que des modifications précoces des réseaux locomoteurs spinaux ont lieudès les stades précoces du développement chez un modèle animal de la SLA, la souris SOD1.C’est dans ce cadre général que nous avons émis l’hypothèse que des altérations précoces dessystèmes neuromodulateurs pourraient intervenir dans la physiopathologie de la SLA. Dansun premier temps, nous avons comparé la modulation monoaminergique des réseaux moteursspinaux en réalisant des enregistrements extracellulaires de l’activité locomotrice générée parla préparation de moelle épinière isolée chez la souris nouveau-née sauvage et SOD1. Nousnous sommes ensuite attachés en combinant des enregistrements électrophysiologiques extraetintracellulaires avec des techniques d’immunohistochimie et de biologie cellulaire à décrirela mise en place et l’évolution avec l’âge des synapses cholinergiques reçues par lesmotoneurones en provenance d’interneurones de la lamina X : les boutons en C. Enfin, nousavons initié une approche (1) comportementale sur le long terme de l’activité motrice dessouris SOD1 et (2) des capacités plastiques des synapses glutamatergiques reçues par lesmotoneurones en culture. L’ensemble de ces travaux, nous a permis de mettre en évidence desaltérations précoces et évolutives des principaux systèmes neuromodulateurs spinaux:cholinergique, dopaminergique et noradrénergique chez les animaux SOD1. Nos résultatsmontrent pour la première fois (1) qu’une dynamique complexe des récepteurs M2 sous lesboutons en C existe et que celle-ci est perturbée chez les souris SOD1 et (2) que lesmotoneurones ne sont pas les seuls neurones à dégénérer dans la moelle de ces animaux maisque les neurones cholinergiques de la lamina X situés dans les segments lombaires L2 sontaussi la cible de processus neurodégénératifs. / Neuromodulatory systems play a crucial role in the establishment and regulation ofspinal motor networks to finely adjust the locomotor rhythm and pattern to the internal andexternal constraints. It is now well admitted that alterations in neuromodulatory functions areinvolved in diverse neurologic disorders. Amyotrophic lateral sclerosis is a neurodegenerativedisease characterized by the specific loss of cortical and spinal motor neurons. A growingbody of evidence now suggests that although ALS syndromes occur in adulthood, alterationscan be detected as early as at the embryonic stages in the spinal cord of the rodent model ofALS, the SOD1 mouse. In this context, we hypothesized that early alterations in the spinalneuromodulatory systems may be involved in the pathophysiology of ALS. To answer thisquestion, in a first step, we compared the monoaminergic modulation of spinal network byrecording extracellularly the fictive locomotion produced in the in vitro spinal cordpreparation form newborn wild-type and SOD1 mice. By combining extra- intracellularrecordings with immunohistochemical and cellular biology technics, we aimed, in a secondstep, to investigate the cholinergic synapses arising onto motoneurons and their neuronalsource, the lamina X interneurons as a function of the mouse age. Finally, we initiated (1) aninnovative behavioural study of mouse motor habits and (2) an analysis of the synapticplasticity of glutamatergic synapses imping on motoneurons in culture. Altogether, our datademonstrated early and progressive changes of the major spinal neuromodulatory systems:cholinergic, dopaminergic and noradrenergic. Our data show for the first time that: (1) M2receptors undergo a complex dynamic under C-bouton that is completely disturbed in SOD1motoneurons and (2) motoneurons are not the only cellular subtype to degenerate in SOD1mice. Indeed, we found evidence that neurodegenerative processes also target lamina Xcholinergic interneurons in the SOD1 spinal cord.
35

Managing Service Dependencies in Service Compositions

Winkler, Matthias 21 December 2010 (has links) (PDF)
In the Internet of Services (IoS) providers and consumers of services engage in business interactions on service marketplaces. Provisioning and consumption of services are regulated by service level agreements (SLA), which are negotiated between providers and consumers. Trading composite services requires the providers to manage the SLAs that are negotiated with the providers of atomic services and the consumers of the composition. The management of SLAs involves the negotiation and renegotiation of SLAs as well as their monitoring during service provisioning. The complexity of this task arises due to the fact that dependencies exist between the different services in a composition. Dependencies between services occur because the complex task of a composition is distributed between atomic services. Thus, the successful provisioning of the composite service depends on its atomic building blocks. At the same time, atomic services depend on other atomic services, e.g. because of data or resource requirements, or time relationships. These dependencies need to be considered for the management of composite service SLAs. This thesis aims at developing a management approach for dependencies between services in service compositions to support SLA management. Information about service dependencies is not explicitly available. Instead it is implicitly contained in the workflow description of a composite service, the negotiated SLAs of the composite service, and as application domain knowledge of experts, which makes the handling of this information more complex. Thus, the dependency management approach needs to capture this dependency information in an explicit way. The dependency information is then used to support SLA management in three ways. First of all dependency information is used during SLA negotiation the to ensure that the different SLAs enable the successful collaboration of the services to achieve the composite service goal. Secondly, during SLA renegotiation dependency information is used to determine which effects the renegotiation has on other SLAs. Finally, dependency information is used during SLA monitoring to determine the effects of detected violations on other services. Based on a literature study and two use cases from the logistics and healthcare domains different types of dependencies were analyzed and classified. The results from this analysis were used as a basis for the development of an approach to analyze and represent dependency information according to the different dependency properties. Furthermore, a lifecycle and architecture for managing dependency information was developed. In an iterative approach the different artifacts were implemented, tested based on two use cases, and refined according to the test results Finally, the prototype was evaluated with regard to detailed test cases and performance measurements were executed. The resulting dependency management approach has four main contributions. Firstly, it represents a holistic approach for managing service dependencies with regard to composite SLA management. It extends existing work by supporting the handling of dependencies between atomic services as well as atomic and composite services at design time and during service provisioning. Secondly, a semi-automatic approach to capturing dependency information is provided. It helps to achieve a higher degree of automation as compared to other approaches. Thirdly, a metamodel for representing dependency information for SLA management is shown. Dependency information is kept separately from SLA information to achieve a better separation of concerns. This facilitates the utilization of the dependency management functionality with different SLA management approaches. Fourthly, a dependency management architecture is presented. The design of the architecture ensures that the components can be integrated with different SLA management approaches. The test case based evaluation of the dependency management approach showed its feasibility and correct functioning in two different application domains. Furthermore, the performance evaluation showed that the automated dependency management tasks are executed within the range of milliseconds for both use cases. The dependency management approach is suited to support the different SLA management tasks. It supports the work of composite service providers by facilitating the SLA management of complex service compositions.
36

SERVICE LEVEL AGREEMENT BASED ARCHITECTURES AND MECHANISMS IN PRIORITY-AWARE SHARED MESH OPTICAL NETWORKS

Nafarieh, Alireza 05 December 2011 (has links)
Service providers’ goals include providing reliable connections with the minimum allocated resources over a shared-mesh path restoration scheme in WDM networks. However, in some cases, the requested parameters in an SLA are beyond the capacity of the network, and the connection is typically blocked. To give the customer a chance to choose another provider, or in the case of having only one provider, to comply with the provider’s network capacity, new SLA-based architectures and mechanisms are required to be introduced to provide better service to prioity-aware shared mesh WDM networks. To achieve this goal, the dissertation’s contributions focus on three main characteristics of the network design: i) A dynamic SLA negotiation infrastructure to negotiate and propagate crucial SLA parameters, ii) Path attributes which can provide a better picture of network resources and status and are suitable to be propagated by the negotiating system, and iii) Algorithms benefiting from the path attributes to improve the blocking probability and resource utilization of the network. To fulfill the first goal of the contributions, a dynamic SLA negotiation mechanism for both intra and inter-domain communications using OSPF and BGP protocols is proposed. Link attributes via intra-domain, and new proposed TE path attributes through inter-domain mechanisms are advertised. Several novel path constraints and attributes are proposed which are dynamically updated and propagated through the network over the connections provisioning process period to satisfy the second objective of the contributions in this dissertation. The path availability, holding time, SLA violation risk, and path risk factor are the important characteristics of the proposed path attributes. As the third goal considered for the contributions, novel priority-aware algorithms and SLA-based mechanisms are proposed to improve the network performance for different traffic types of various priority classes. The algorithms and mechanisms proposed in this thesis take advantage of the new path attributes and SLA negotiation infrastructure to better serve high-priority connection requests at the lowest cost. The mechanisms and network architectures proposed in this work are a solution for the high-priority requests that normally cannot be accommodated as they violate the best availability offered by service providers.
37

Analysis of Quality of Service in Heterogeneous Wireless Networks / Paslaugų kokybės heterogeniniuose bevieliuose tinkluose tyrimai

Vindašius, Antanas 22 December 2010 (has links)
The dissertation investigates wireless access network performance, ability to control and enforce quality of service (QoS) and track it at user device. The objective of presented research is to investigate wireless access network performance parameter impact on quality of service and develop reference model of QoS monitor, applied for end-user device. In order to reach the objective, the following tasks had to be solved: - To analyze existing measures of QoS evaluation, actual achieved, perceived QoS monitoring and Service Level Agreement (SLA) enforcement. - To analyze performance properties of contemporary wireless user access network technologies in order to determine their capabilities providing data services and employing soft and hard QoS mechanisms. - To analyze network performance characteristics in order to determine factors, influencing quality of service in wireless access networks. - To design principles of evaluation of actually achieved quality of service. - To develop a reference model of QoS requirement composition and monitoring system. - To develop and experimentally test QoS monitor for web browsing service. First chapter of the dissertation reviews QoS definitions, categories, existing methods of QoS evaluation and formulates the problem of QoS and service level agreement enforcement measures. Second chapter presents analysis of various access networks applicable to data and voice services. The analysis is focused on available bit rate, referred to... [to full text] / Disertacijoje nagrinėjama belaidės prieigos tinklų savybės, gebėjimas kontroliuoti ir užtikrinti paslaugos kokybę (QoS) bei stebėti ją vartotojų įrenginiuose. Darbo tikslas – ištirti belaidės prieigos tinklų darbo parametrų įtaką paslaugos kokybei ir sukurti apibendrintą paslaugos kokybės stebėsenos priemonių, taikomų galutinio vartotojo įrenginyje, modelį. Šiam tikslui pasiekti, sprendžiami tokie uždaviniai: - Išanalizuoti esamas paslaugos kokybės vertinimo, realiai patirtos ir suvokiamos kokybės stebėsenos bei paslaugų lygmens susitarimų (SLA) užtikrinimo priemones. - Išanalizuoti dabartinių belaidžių vartotojo prieigos technologijų savybes teikiant duomenų perdavimo paslaugas ir taikant griežtus bei švelnius paslaugos kokybės užtikrinimo mechanizmus. - Išanalizuoti belaidžių prieigos tinklų charakteristikas siekiant nustatyti faktorius, įtakojančius paslaugos kokybę belaidžiuose prieigos tinkluose. - Suformuluoti realiai pasiektos paslaugos kokybės vertinimo principus. - Sukurti apibendrintą paslaugos kokybės reikalavimų sudarymo ir stebėsenos sistemos vartotojo įrenginyje modelį. - Sukurti ir eksperimentiškai įvertinti paslaugos kokybės stebėsenos sistemą interneto naršymo paslaugai. Pirmajame disertacijos skyriuje pateikiama žinomų paslaugos kokybės vertinimo ir valdymo procesų apžvalga, koncentruojantis į vartotojo perspektyvą ir galimybes įvertinti realiai gaunamą ir vartotojo suvokiamą paslaugų kokybę. Antrajame skyriuje pateikiama paplitusių belaidės prieigos tinklų... [toliau žr. visą tekstą]
38

Gestion de ressources de façon "éco-énergétique" dans un système virtualisé : application à l'ordonnanceur de marchines virtuelles / Design and implementation of an energy-effcient resources manager in a virtualized system : case of virtuals machines scheduler

Mayap Kamga, Christine 26 June 2014 (has links)
Face au coût de la gestion locale des infrastructures informatiques, de nombreuses entreprises ont décidé de la faire gérer par des fournisseurs externes. Ces derniers, connus sous le nom de IaaS (Infrastructure as a Service), mettent des ressources à la disposition des entreprises sous forme de machine virtuelle (VM - Virtual Machine). Ainsi, les entreprises n'utilisent qu'un nombre limité de machines virtuelles capables de satisfaire leur besoin. Ce qui contribue à la réduction des coûts de l'infrastructure informatique des entreprises clientes. Cependant, cette externalisation soulève pour le fournisseur, les problèmes de respect d'accord de niveau de service (SLA - Service Layer Agreement) souscrit par le client et d'optimisation de la consommation énergétique de son infrastructure. Au regard de l'importance que revêt ces deux défis, de nombreux travaux de recherches se sont intéressés à cette problématique. Les solutions de gestion d'énergie proposées consistent à faire varier la vitesse d'exécution des périphériques concernés. Cette variation de vitesse est implémentée, soit de façon native parce que le périphérique dispose des mécaniques intégrés, soit par simulation à travers des regroupements (spatial et temporel) des traitements. Toutefois, cette variation de vitesse permet d'optimiser la consommation énergétique d'un périphérique mais, a pour effet de bord d'impacter le niveau de service des clients. Cette situation entraine une incompatibilité entre les politiques de variation de vitesse pour la baisse d'énergie et le respect de l'accord de niveau de service. Dans cette thèse, nous étudions la conception et l'implantation d'un gestionnaire de ressources "éco énergétique" dans un système virtualisé. Un tel gestionnaire doit permettre un partage équitable des ressources entre les machines virtuelles tout en assurant une utilisation optimale de l'énergie que consomment ces ressources. Nous illustrons notre étude avec un ordonnanceur de machines virtuelles. La politique de variation de vitesse est implantée par le DVFS (Dynamic Voltage Frequency Scaling) et l'allocation de la capacité CPU aux machines virtuelles l'accord de niveau de service à respecter. / Considering the cost of local management of the computing infrastructures, numerous companies decided to delegate theirs to providers. These latter are known as an Infrastructure as a Service (IaaS) and provide resources to companies in the form of virtual machine (VM). This decision to outsource contributes to lower the cost of IT infrastructure of the customer companies. However, it raises for the provider, the problems of the respect of the Service Layer agreement (SLA) of the customer and of the optimization of the energy consumption of his infrastructure. With regard to the importance of these two challenges, many research works have focused on this problem. The proposed energy management solutions consist in varying the execution speed of the affected devices. This variation of speed is implemented either natively because the device has integrated mechanics, or by simulation through a spatial or temporal batching requests. However, this variation of speed optimizes the energy consumption of a device but has the side effect of degrading the customers SLA. In this thesis, we study the design and the implementation of an energy-efficient resources manager in a virtualized system. Such a manager must ensure a fair share of resources among VMs while ensuring optimal use of the energy consumed by the resources. We illustrate our study thanks to a scheduler of VMs. The DVFS constitutes our energy management policy and the CPU capacity of the VMs the SLA to respect.
39

Automation of The SLA Life Cycle in Cloud Computing

Ghumman, Waheed Aslam 09 October 2017 (has links) (PDF)
Cloud computing has become a prominent paradigm to offer on-demand services for softwares, infrastructures and platforms. Cloud services are contracted by a service level agreement (SLA) between a cloud service provider (CSP) and a cloud service user (CSU) which contains service definitions, quality of service (QoS) parameters, guarantees and obligations. Cloud service providers mostly offer SLAs in descriptive format which is not directly consumable by a machine or a system. The SLA written in natural language may impede the utility of rapid elasticity in a cloud service. Manual management of SLAs with growing usage of cloud services can be a challenging, erroneous and tedious task especially for the CSUs acquiring multiple cloud services. The necessity of automating the complete SLA life cycle (which includes SLA description in machine readable format, negotiation, monitoring and management) becomes imminent due to complex requirements for the precise measurement of QoS parameters. Current approaches toward automating the complete SLA life cycle, lack in standardization, completeness and applicability to cloud services. Automation of different phases of the SLA life cycle (e.g. negotiation, monitoring and management) is dependent on the availability of a machine readable SLA. In this work, a structural specification for the SLAs in cloud computing (S3LACC in short) is presented which is designed specifically for cloud services, covers complete SLA life cycle and conforms with the available standards. A time efficient SLA negotiation technique is accomplished (based on the S3LACC) for concurrently negotiating with multiple CSPs. After successful negotiation process, next leading task in the SLA life cycle is to monitor the cloud services for ensuring the quality of service according to the agreed SLA. A distributed monitoring approach for the cloud SLAs is presented, in this work, which is suitable for services being used at single or multiple locations. The proposed approach reduces the number of communications of SLA violations to a monitoring coordinator by eliminating the unnecessary communications. The presented work on the complete SLA life cycle automation is evaluated and validated with the help of use cases, experiments and simulations.
40

Automation of The SLA Life Cycle in Cloud Computing

Ghumman, Waheed Aslam 30 January 2017 (has links)
Cloud computing has become a prominent paradigm to offer on-demand services for softwares, infrastructures and platforms. Cloud services are contracted by a service level agreement (SLA) between a cloud service provider (CSP) and a cloud service user (CSU) which contains service definitions, quality of service (QoS) parameters, guarantees and obligations. Cloud service providers mostly offer SLAs in descriptive format which is not directly consumable by a machine or a system. The SLA written in natural language may impede the utility of rapid elasticity in a cloud service. Manual management of SLAs with growing usage of cloud services can be a challenging, erroneous and tedious task especially for the CSUs acquiring multiple cloud services. The necessity of automating the complete SLA life cycle (which includes SLA description in machine readable format, negotiation, monitoring and management) becomes imminent due to complex requirements for the precise measurement of QoS parameters. Current approaches toward automating the complete SLA life cycle, lack in standardization, completeness and applicability to cloud services. Automation of different phases of the SLA life cycle (e.g. negotiation, monitoring and management) is dependent on the availability of a machine readable SLA. In this work, a structural specification for the SLAs in cloud computing (S3LACC in short) is presented which is designed specifically for cloud services, covers complete SLA life cycle and conforms with the available standards. A time efficient SLA negotiation technique is accomplished (based on the S3LACC) for concurrently negotiating with multiple CSPs. After successful negotiation process, next leading task in the SLA life cycle is to monitor the cloud services for ensuring the quality of service according to the agreed SLA. A distributed monitoring approach for the cloud SLAs is presented, in this work, which is suitable for services being used at single or multiple locations. The proposed approach reduces the number of communications of SLA violations to a monitoring coordinator by eliminating the unnecessary communications. The presented work on the complete SLA life cycle automation is evaluated and validated with the help of use cases, experiments and simulations.

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