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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.
61

Virtual Frameworks for Source Migration

Chi, Jack January 2004 (has links)
<em>Virtual Frameworks</em> for source migration is a methodology to extract classes and interfaces from one or more frameworks used by an application. After migration, a new set of frameworks called virtual frameworks can replace the original frameworks used. The classes and interfaces extracted are used to create a proxy layer for these new frameworks. The application then depends on this proxy layer, and through it the new frameworks, rather than on the original frameworks. A combination of three patterns: Bridge, Adapter, and Proxy are used in these new frameworks. By doing so the changes made to the application source code are minimized during migration.
62

Real-time hierarchical hypervisor

Poon, Wing-Chi 07 February 2011 (has links)
Both real-time virtualization and recursive virtualization are desirable properties of a virtual machine monitor (or hypervisor). Although the prospect for virtualization and even recursive virtualization has become better as the PC hardware becomes faster, the real-time systems community so far has not been able to reap much benefits. This is because no existing virtualization mechanism can properly support the stringent timing requirements needed by real-time systems. It is hard to do real-time virtualization, and it is even harder to do it recursively. In this dissertation, we propose a framework whereby the hypervisor is capable of running real-time guests and participating in recursive virtualization. Such a hypervisor is called a real-time hierarchical hypervisor. We first look at virtualization of abstract resource types from the real-time systems perspective. Unlike the previous work on recursive real-time partitioning that assumes fully-preemptable resources, we concentrate on other and often more practical types of scheduling constraints, especially the non-preemptive and limited-preemptive ones. Then we consider the current x86 architecture and explore the problems that need to be addressed for real-time recursive virtualization. We drill down on the problem that affects timing properties the most, namely, the recursive forwarding and delivery of interrupts, exceptions and intercepts. We choose the x86 architecture because it is popular and readily available, but it is by no means the only architecture of choice for real-time recursive virtualization. We conclude the research with an architecture-independent discussion on future possibilities in real-time recursive virtualization. / text
63

Ekspedicinės ir kelių transporto įmonės veiklos efektyvumo lyginamasis tyrimas / Comparative research on efficiency of road freight forwarding and transport company

Česnulevič, Jelena 26 June 2009 (has links)
Šio darbo tikslas – atlikti ekspedicinių ir transporto įmonių veiklos efektyvumo lyginamąjį tyrimą. Tyrimui turi įtakos esama situacija transporto sektoriuje, todėl darbe įvertinamos kelių transporto sektoriaus plėtros perspektyvos bei analizuojamos krovinių vežimo apimtys per pastaruosius 5 metus. Darbe remiamasi apklausoje dalyvavusių respondentų atsakymais apie jų įmonių veiklos efektyvumą. Atlikus tyrimą buvo nustatyta, kad ekspedicinė veikla (dabartinėmis sąlygomis) yra efektyvesnė, nei vežimo. Tam turėjo įtakos tai, kad 2008 metai buvo nuostolingi vežėjams, nes didėjo degalų kainos bei mažėjo krovinių vežimo apimtys. Remiantis respondentų atsakymais, galima teigti, kad transporto veikla tampa mažiau pelninga, nes beveik pusė jų, jeigu tektų rinktis iš naujo, kuo užsiimti, pasirinktų kitą veiklą. Kita dalis respondentų nurodė, kad užsiimtų ekspedijavimu. O tai reiškia, kad ekspeditorių padėtis yra lengvesnė nei vežėjų. Tik maža dalis apklaustųjų pasirinktų vežimo veiklą. Darbą sudaro 5 dalys: įvadas, analitinė-metodinė dalis, eksperimentinė-tiriamoji dalis, išvados ir siūlymai, literatūros sąrašas. Darbo apimtis – 81 p. teksto be priedų, 13 iliustracijų, 3 lentelės, 52 bibliografiniai šaltiniai. / The aim of this work - to perform comparative analysis of forwarding and transportation companies activity efficiency. The present situation in the transport sector has influence upon the analysis, therefore in the work, the perspectives of road transport sector expansion are evaluated, also cargo transportation volumes during the latter 5 years are analyzed. The work is based on the answers of the respondents, who participated in the survey - about the efficiency of their companies' activity. When the analysis was made, it was established, that the forwarding activity (in the present circumstances) is more effective than the transportation activity. Also this fact, that the year 2008 was loss-making to the carriers, because the fuel prices increased and the volumes of cargo transportation decreased, had influence on the research results. On the grounds of respondent answers, it can be stated, that transportation activity becomes less profitable, because nearly half of the respondents, if they had a possibility to choose newly what activity to take, would choose the other activity. Other part of the respondents has indicated that they would use forwarding. And this means, that the condition of forwarders is easier than the carriers' condition. Only the little part of the respondents would choose the carrier activity. The work is made from 5 parts: introduction, analytical-methodical part, experimental-investigative part, conclusions and suggestions, list of literature. The... [to full text]
64

Įmonės CAF konkurencingumo didinimas marketingo priemonėmis / Increasing of company‘s „CAF“ competetive abilities by means of marketing

Miliušis, Paulius 25 August 2008 (has links)
Šiame darbe yra apibūdinami teoriniai ekspedicinės veiklos aspektai, apibrėžiamos konkurencijos ir konkurencingumo sąvokos, pristatomas marketingo priemonių kompleksas ir atskleidžiamos jų panaudojimo galimybės ekspedicinėje veikloje. Darbe remiamasi konkrečios ekspedicinės įmonės „CAF“ pavyzdžiu, analizuojama jos veikla bei vertinamas konkurencingumas ir jo didinimo galimybės marketingo priemonėmis. „CAF“ įmonės konkurencingumui įvertinti naudojamas ir kokybinis tyrimas taikant interviu metodą, o gauti tyrimo rezultatai pateikiami kaip reikšmingi kitų ekspedicinių kompanijų konkurencingumo didinimui. / This work is written to show freight forwarder company’s competitive ability and to find out which changes could influence company’s profit and create more effective managing. It was taken an example of real Lithuanian freight forwarder company. It was interviewed employees of this company and analyzed their reports to realize main problems in freight forwarding activity and find out which actions could make company’s action more competetive.
65

On information-centric routing and forwarding in the internet of things / Du routage centré contenu pour l'internet des objets

Enguehard, Marcel 15 April 2019 (has links)
Les réseaux centrés contenus (ICN) sont considérés comme une solution aux nouveaux défis et modes de communication liés à l'émergence de l'Internet des Objets (IoT). Pour confirmer cette hypothèse, la problématique fondamentale du routage sur les réseaux ICN-IoT doit être abordée. Cette thèse traite de ce sujet à travers l'architecture IoT.Premièrement, une méthode sécurisée est introduite pour acheminer des paquets ICN à partir de coordonnées géographiques dans un réseau sans-fil de capteurs à faible puissance. Elle est comparée à une inondation optimisée du réseau inspirée des approches existant dans la littérature. En particulier, leur faisabilité et passage à l'échelle sont évalués via un modèle mathématique. Le modèle est paramétré grâce à des données réalistes issues de simulation, de la littérature, et d'expériences sur des capteurs. Il est montré que le routage géographique permet de diviser la mémoire nécessaire sur les capteurs par deux et de réduire considérablement le coût énergétique du routage, en particulier pour des topologies dynamiques.Ensuite, ICN est utilisé pour contrôler l'admission à une plate-forme de calcul de type Fog afin de garantir le temps de réponse. La stratégie de contrôle d'admission proposée, le LRU-AC, utilise l'algorithme Least-Recently-Used (LRU) pour apprendre en direct la distribution de popularité des requêtes. Son efficacité est démontrée grâce à un modèle fondé sur un réseau de files d'attente. Une implémentation du LRU-AC est proposé, utilisant des filtres de Bloom pour satisfaire aux contraintes des cartes FPGA. Son bien-fondé est prouvé par un modèle mathématique et son efficacité en termes de latence et débit démontrée.Enfin, on présente vICN, un outil pour la gestion et la virtualisation de réseaux ICN-IoT. Il s'agit d'une plate-forme qui unifie la configuration et la gestion des réseaux et des applications en exploitant les progrès des techniques d'isolation et de virtualisation. vICN est flexible, passe à l'échelle, et peut remplir différents buts : expériences à grande échelle reproductibles pour la recherche, démonstrations mélangeant machines émulées et physiques, et déploiements réels des technologies ICN dans les réseaux IP existants. / As the Internet of Things (IoT) has brought upon new communication patterns and challenges, Information-Centric Networking (ICN) has been touted as a potential solution. To confirm that hypothesis, the fundamental issue of routing and forwarding in the ICN-IoT must be addressed. This thesis investigates this topic across the IoT architecture.First, a scheme to securely forward ICN interests packets based on geographic coordinates is proposed for low-power wireless sensor networks (WSN). Its efficiency is compared to an optimized flooding-based scheme similar to current ICN-WSN approaches in terms of deployability and scalability using an analytical model. Realistic data for the model is derived from a mixture of simulation, literature study, and experiments on state-of-the-art sensor boards. Geographic forwarding is shown to halve the memory footprint of the ICN stack on reference deployments and to yield significant energy savings, especially for dynamic topologies. Second, ICN is used to enhance admission control (AC) to fixed-capacity Edge-computing platforms to guarantee request-completion time for latency-constrained applications. The LRU-AC, a request-aware AC strategy based on online learning of the request popularity distribution through a Least-Recently-Used (LRU) filter, is proposed. Using a queueing model, the LRU-AC is shown to decrease the number of requests that must be offloaded to the Cloud. An implementation of the LRU-AC on FPGA hardware is then proposed, using Ageing Bloom Filters (ABF) to provide a compact memory representation. The validity of using ABFs for the LRU-AC is proven through analytical modelling. The implementation provides high throughput and low latency.Finally, the management and virtualization of ICN-IoT networks are considered.vICN (virtualized ICN), a unified intent-based framework for network configuration and management that uses recent progress in resource isolation and virtualization techniques is introduced. It offers a single, flexible and scalable platform to serve different purposes, ranging from reproducible large-scale research experimentation to demonstrations with emulated and/or physical devices and network resources and to real deployments of ICN in existing IP networks.
66

Erfarenhetsåterföring : En objektiv granskning av ett Construction Management-företag / Experience feedback : An objective study of a Construction Management corporation

Svensson, Jimmy, Werme, Thomas January 2013 (has links)
Byggbranschen har blivit kritiserad för att vara en bransch där tidspress och underprioriterad syn på lärande varit ett hinder för erfarenhetsåterföring. Rapportens syfte är att objektivt studera erfarenhetsåterföring inom Midroc Entreprenad för att om möjligt utläsa huruvida önskad, kontra faktisk erfarenhetsåterföring sker idag samt ge förbättringsförlag. För att göra detta har en teoretisk grund lagts med utgångspunkt i litterära studier inom kunskapsöverföring, lärande och erfarenhetsåterföring. Analys är underbyggd i intervjuer och enkätundersökning utförda på Midroc Entreprenad. Det finns få direktiv för hur erfarenhetsåterföring bör genomföras bara att det ska göras efter avslutat projekt, vilket efterföljs. De lärdomar som diskuteras vid avslut förmedlas till stor del muntligt, därav har förslag till dokumentation och annan distribuering lagts fram. Eftersom byggprojekt fortlöper under långa tidsperioder bör mindre utvärderingar äga rum under entreprenaden för att tillvarata lärdomar som annars glöms bort. Denna feedback bör ges när den är aktuell, därav orimligt att ge korrekt sådan i senare skede. En vilja att påverka erfarenhetsåterföringen finns, men hinns inte riktigt med. Merparten av de anställda upplever en öppenhet inom organisationen och känner samhörighet med sina medarbetare. Detta stämmer väl överens med det som organisationen eftersträvar och är en förutsättning för lyckad erfarenhetsåterföring. / The construction industry has been criticised of being a trade where time pressure and a deprioritised view of learning is an obstacle for experience feedback. The purpose of this thesis is to present an objective survey of the experience feedback within Midroc Entreprenad to verify whether the experience feedback wanted is equal to the actual and to provide suggestion for improvement. To enable this, a theoretical study has been done on knowledge forwarding, learning and experience feedback. Interviews and questionnaire on Midroc Entreprenad have been used for the analysis of this thesis. There are few directives for the process of experience feedback on the company, only that it is to be done at the end of a project, which is fulfilled. The lessons learned that are discussed are mainly orally transferred, therefore a proposition for documenting and distributing these has been presented. There should be several evaluations during a building project due to its severe duration in time, to reduce the risk of lessons learned being forgotten. This feedback should be given instantaneously and proper feedback is therefore unreasonable to give at a later stage. There is a will to influence to the experience feedback, but time is not enough. A majority of the employees experience openness and belonging within the organisation. This concurs with what the organisation aims at and is a prerequisite to sustain successful experience feedback.
67

Mac Layer And Routing Protocols For Wireless Ad Hoc Networks With Asymmetric Links And Performance Evaluation Studies

Wang, Guoqiang 01 January 2007 (has links)
In a heterogeneous mobile ad hoc network (MANET), assorted devices with different computation and communication capabilities co-exist. In this thesis, we consider the case when the nodes of a MANET have various degrees of mobility and range, and the communication links are asymmetric. Many routing protocols for ad hoc networks routinely assume that all communication links are symmetric, if node A can hear node B and node B can also hear node A. Most current MAC layer protocols are unable to exploit the asymmetric links present in a network, thus leading to an inefficient overall bandwidth utilization, or, in the worst case, to lack of connectivity. To exploit the asymmetric links, the protocols must deal with the asymmetry of the path from a source node to a destination node which affects either the delivery of the original packets, or the paths taken by acknowledgments, or both. Furthermore, the problem of hidden nodes requires a more careful analysis in the case of asymmetric links. MAC layer and routing protocols for ad hoc networks with asymmetric links require a rigorous performance analysis. Analytical models are usually unable to provide even approximate solutions to questions such as end-to-end delay, packet loss ratio, throughput, etc. Traditional simulation techniques for large-scale wireless networks require vast amounts of storage and computing cycles rarely available on single computing systems. In our search for an effective solution to study the performance of wireless networks we investigate the time-parallel simulation. Time-parallel simulation has received significant attention in the past. The advantages, as well as, the theoretical and practical limitations of time-parallel simulation have been extensively researched for many applications when the complexity of the models involved severely limits the applicability of analytical studies and is unfeasible with traditional simulation techniques. Our goal is to study the behavior of large systems consisting of possibly thousands of nodes over extended periods of time and obtain results efficiently, and time-parallel simulation enables us to achieve this objective. We conclude that MAC layer and routing protocols capable of using asymmetric links are more complex than traditional ones, but can improve the connectivity, and provide better performance. We are confident that approximate results for various performance metrics of wireless networks obtained using time-parallel simulation are sufficiently accurate and able to provide the necessary insight into the inner workings of the protocols.
68

Détection de la retransmission sélective sur les réseaux de capteurs

Haddad, Edgard 04 1900 (has links)
L'attaque de retransmission sélective est une menace sérieuse dans les réseaux de capteurs sans fil (WSN), en particulier dans les systèmes de surveillance. Les noeuds peuvent supprimer de manière malicieuse certains paquets de données sensibles, ce qui risque de détruire la valeur des données assemblées dans le réseau et de diminuer la disponibilité des services des capteurs. Nous présentons un système de sécurité léger basé sur l'envoi de faux rapports pour identifier les attaques de retransmission sélective après avoir montré les inconvénients des systèmes existants. Le grand avantage de notre approche est que la station de base attend une séquence de faux paquets à un moment précis sans avoir communiqué avec les noeuds du réseau. Par conséquent, elle sera capable de détecter une perte de paquets. L'analyse théorique montre que le système proposé peut identifier ce type d'attaque et peut alors améliorer la robustesse du réseau dans des conditions d'un bon compromis entre la fiabilité de la sécurité et le coût de transmission. Notre système peut atteindre un taux de réussite élevé d‟identification face à un grand nombre de noeuds malicieux, tandis que le coût de transmission peut être contrôlé dans des limites raisonnables. / The selective forwarding attack is a serious threat in wireless sensor networks (WSN), especially in surveillance systems. Nodes can maliciously delete some sensitive data packets, which could destroy the value of the data assembled in the network and reduce its sensors availability. After describing the drawbacks of the existing systems in this thesis, we will present a lightweight security system based on sending fake reports used to identify selective forwarding attacks. The great advantage in our approach is that the base station expects a number of packets at a specific time. Therefore, it will be able to detect missing or delayed packets. Theoretical analysis shows that the proposed system can identify this type of attack, which will improve the robustness of the network under conditions of a good tradeoff between the security, reliability and communication overhead. Our system can achieve a high ratio of identification when facing a large number of malicious nodes, while the communication overhead can be controlled within reasonable bounds.
69

Finanční analýza vybraného podniku cestovního ruchu / Financial Analysis of a Specified Tourism Company

Jiranová, Tereza January 2010 (has links)
This thesis primarily deals with financial analysis of selected tourism company, the haulier company concerning on the area of incoming -- 493 Servis, s.r.o. The financial analysis should allow getting closer information about economic and financial health of the company. In the introduction of the thesis there is more than just this one aim settled. The additional aims concern the methodology and the area of transportation. The theoretical part summarizes the facts regarding the financial analysis and subsequently defined the area of tourism enterprises, focusing on the area of transportation. Knowledge summarized in the theoretical part is applied on the company 493 Servis, s.r.o. in the practical part since the practical part of the thesis includes the specification of the company, external financial analysis based on company financial statements and partial internal analysis based on the internal documentation. The financial analysis is enriched of graphical material. The summary of assumptions which are derived from the character of the analyzed company and their fulfilment based on analysis is the part of the evaluation. The evaluation also summarizes the factors which could cause distortion. Thanks to the concrete outputs, the thesis could be useful within the area of decision making for management of the company analysed.
70

Överensstämmelse mellan samarbetande organisationers mål och motivationsfaktorer : En fallstudie i transportbranschen

Jansson, Maria, Bergvall, Stefan January 2019 (has links)
Syfte: Syftet är att undersöka överensstämmelse avseende mål och motivationsfaktorer mellan samarbetande organisationer. Syftet är även att undersöka hur denna överensstämmelse samt identifierade mål och motivationsfaktorer kan bidra till en ersättningsmodell som främjar en bra transporttjänst. Design och metoder: Denna studie har genomförts som en fallstudie där samarbetet mellan ett speditionsföretag och två åkerier varit i fokus. Som metod för datainsamling till fallstudien användes en kombination av semistrukturerade intervjuer och rangordningstabeller. Till analysen av det empiriska materialet hämtades inspiration från flera olika metoder, dels hämtades inspiration från den tematiska analysmetoden men även från aktiviteterna sortera, reducera och argumentera. Slutligen användes även aktiviteten jämförelse för att kunna analysera överensstämmelsen mellan speditionsföretaget och åkerierna. Resultat: Resultatet gällande målöverensstämmelsen visade att åkerierna hade en begränsad kännedom om speditionsföretagets uttalade mål vilket i detta fall likställs med ingen till låg överensstämmelse. En större överensstämmelse identifierades dock avseende områdena förväntningar och framtida mål. Gällande motivationsöverensstämmelsen framkom det att speditionsföretaget hade en begränsad kännedom om vad som motiverar åkerierna, chaufförerna och transportplanerarna vilket innebär att överensstämmelsen därmed kan anses som låg. Resultatet visade även att en prestationsbaserad ersättningsmodell i tre nivåer bör möjliggöra för en högre måluppfyllnad och kunna leda till högre motivation. Bidrag: Studien har i viss mån bidragit till en utvecklad förståelse för hur olika parter i samarbetande organisationer uppfattar mål och förväntningar från den beställande parten och motivation hos den levererande parten. Vidare har studien bidragit med ett förslag på en ersättningsmodell bestående av tre prestationsbaserade ersättningsnivåer där olika mål är kopplade till respektive nivå. Begränsningar och framtida forskning: Den horisontella överensstämmelsen mellan samarbetande organisationer inom transportbranschen har visat sig vara mycket komplex och svårt att skapa en helhetsbild kring. Generaliserbarheten av resultaten till andra samarbetande organisationer anses utifrån det som relativt låg. Fortsatta studier föreslås inom området horisontell överensstämmelse, främst mellan samarbetande organisationer. En intressant inriktning kan då vara att undersöka om den horisontella överensstämmelsen mellan samarbetande organisationer kan ge samma positiva resultat avseende organisationers effektivitet och resultat som andra typer av överensstämmelse. Ett behov har även identifierats i form av att kunna namnge samarbetet mellan speditionsföretaget och åkerierna, vilket även det rekommenderas som ett område för fortsatt forskning. / Purpose: The purpose of this study is to investigate the alignment regarding goals and motivation factors between cooperating organizations. The purpose is also to investigate how this alignment, as well as identified goals and motivation factors, can contribute to a transaction model that promotes a good transport service. Design and methods: This study has been carried out as a case study where the cooperation between a forwarding company and two road haulage contractors has been in focus. As a method for data collection for the case study a combination of semi-structured interviews and ranking tables was used. The analysis of the empirical material was inspired by several different methods. Firstly, inspiration was derived from the thematic analysis method but also from the activities sorting, reducing and arguing. Finally, comparison was used to analyze the alignment between the forwarding company and the road haulage contractors. Result: The result regarding the goal alignment showed that the road haulage contractors had a limited knowledge of the forwarding company's stated goals, which in this case is equated with a low alignment. However, greater alignment was identified regarding the areas of expectations and future goals. Regarding the motivation alignment it emerged that the forwarding company had a limited knowledge of what motivates the road haulage contractors, the chauffeurs and the transport planners, which means that the alignment can be considered low. The result also showed that a performance-based transaction model in three levels might improve both goal fulfillment and contribute to higher motivation. Contributions: The study has to some extent contributed to a developed understanding of how different parties in cooperating organizations perceive goals and motivation. Further contributions are the suggested transaction model consisting of three performance-based levels where different goals are linked to each level. Restrictions and future research: The horizontal alignment between cooperating organizations in the transport sector has proved to be very complex and difficult to create an overall picture about. The generalisability of the results to other cooperating organizations is considered relatively low. Continued studies are proposed in the field of horizontal alignment, primarily between cooperating organizations. An interesting approach may then be to investigate whether the horizontal correspondence between cooperating organizations can yield the same positive results regarding organizations' effectiveness and results as other types of alignment. A need has also been identified in the form of being able to name the cooperation between the forwarding company and the road haulage contractors, which is also recommended as an area for continued research.

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