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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.
121

VM allocation in cloud datacenters based on the multi-agent system : an investigation into the design and response time analysis of a multi-agent-based virtual machine (VM) allocation/placement policy in cloud datacenters

Al-ou'n, Ashraf M. S. January 2017 (has links)
Recent years have witnessed a surge in demand for infrastructure and services to cover high demands on processing big chunks of data and applications resulting in a mega Cloud Datacenter. A datacenter is of high complexity with increasing difficulties to identify, allocate efficiently and fast an appropriate host for the requested virtual machine (VM). Establishing a good awareness of all datacenter’s resources enables the allocation “placement” policies to make the best decision in reducing the time that is needed to allocate and create the VM(s) at the appropriate host(s). However, current algorithms and policies of placement “allocation” do not focus efficiently on awareness of the resources of the datacenter, and moreover, they are based on conventional static techniques. Which are adversely impacting on the allocation progress of the policies. This thesis proposes a new Agent-based allocation/placement policy that employs some of the Multi-Agent system features to get a good awareness of Cloud Datacenter resources and also provide an efficient allocation decision for the requested VMs. Specifically, (a) The Multi-Agent concept is used as a part of the placement policy (b) A Contract Net Protocol is devised to establish good awareness and (c) A verification process is developed to fully dimensional VM specifications during allocation. These new results show a reduction in response time of VM allocation and the usage improvement of occupied resources. The proposed Agent-based policy was implemented using the CloudSim toolkit and consequently was compared, based on a series of typical numerical experiments, with the toolkit’s default policy. The comparative study was carried out in terms of the time duration of VM allocation and other aspects such as the number of available VM types and the amount of occupied resources. Moreover, a two-stage comparative study was introduced through this thesis. Firstly, the proposed policy is compared with four state of the art algorithms, namely the Random algorithm and three one-dimensional Bin-Packing algorithms. Secondly, the three Bin-Packing algorithms were enhanced to have a two-dimensional verification structure and were compared against the proposed new algorithm of the Agent-based policy. Following a rigorous comparative study, it was shown that, through the typical numerical experiments of all stages, the proposed new Agent-based policy had superior performance in terms of the allocation times. Finally, avenues arising from this thesis are included.
122

Fyzická zátěž organismu jako faktor ovlivňující kognitivní funkce. / The physical load on the body as a factor influencing perceptual cognitive functions

Frýbort, Pavel January 2014 (has links)
Title: The physical load on the body as a factor influencing perceptual cognitive functions. Objective: The aim of this study is to determine the relationship between the size of the physical load and the visual-motor response time and the accuracy of the decision-making by junior soccer players. Methods: The fourty two respondents (in an average age of 19 ± 1.2 years) participated in the study. It was the single factor quasiexperimental, multilevel and intragroup in which we tried to reveal the causal relationship between the visual-motor response time and the accuracy of the decision-making depending on the size of the previous physical load. We proposed a diagnostic instrument containing the video of the offensive game situations which would allow simultaneous evaluation of the visual-motor response time (using Dartfish software program) and the accuracy of the decision-making (through experts assessment). Results and discussion: The diagnostic instrument contains sixteen video clips of the offensive game situations according to the highest degree of conformity of the panelists. I used polychoric correlation matrix to express dependencies between each game situation within each group comprising four video clips of the offensive game situations. The results of the matrix (range -0.437 to 0.306)...
123

System response times in a simulated driving task : effects on performance, visual attention, subjective state and time estimation

Bauer, Tanja 02 1900 (has links)
The utilisation of navigation systems in cars has given rise to road safety concerns, and the design and functionality of such systems must therefore be adjusted to the users’ needs, since they have to divide their attention between driving and the operation of the navigation system. The study was aimed at finding the optimum system response time (SRT) which would enable a driver to focus as much as possible on the road while attaining an efficient task completion time using an electronic navigational system. The research project consists of two separate experiments and was completed by 10 subjects. Experiment 1 included a temporal reproduction task and a secondary memory task. The subjects had to memorise two symbols and then reproduce six time spans ranging from 1 to 30 s to provide a baseline measurement of their time estimation abilities. Experiment 2 consisted of a simulated automobile driving task. While driving in the simulator the subjects completed a memorising task displayed on a touch screen. The task was presented with seven different system response times (SRTs) ranging from 0 to 30 s. The effects of different SRTs on the eye movement from road to monitor, regarding the duration of fixation and the frequency of change were evaluated. The distribution of gazes to the secondary task was analysed to provide information about the time estimation performance in the driving simulator. Other dependent variables tested were the accuracy of selected items, memory game performance, drive performance and the subjective state of the test person. The results of this study can be employed to find the optimum duration of inter-task delays for in-vehicle technical devices. / Psychology / M.A. (Psychology)
124

Análise de sistemas operacionais de tempo real para aplicações de robótica e automação / Analysis of real time operating systems for robotics and automation applications

Rafael Vidal Aroca 31 October 2008 (has links)
Este trabalho apresenta um estudo sobre sistemas operacionais de tempo real (RTOS) utilizados na implementação da infraestrutura de controle digital para sistemas mecatrônicos, mas serve também como referência para outros sistemas que possuam restrições de tempo. Além de ter um caráter experimental, onde foram medidos e analisados dados como o pior tempo de resposta dos sistemas e a latência para tratamento de interrupções, este trabalho de pesquisa ainda contempla a implementação e uso de RTOS em situações práticas, bem como contempla a construção de uma plataforma geral de pesquisa que servirá de base para futuros trabalhos no laboratório de mecatrônica. Os sistemas analisados neste trabalho foram o VxWorks, QNX, Linux, RTAI, Windows XP, Windows CE e \'mü\'C/OS-II. Outro produto gerado durante este trabalho foi um Live CD para auxiliar na implementação e ensino de conceitos e sistemas de tempo real. / This work presents a study about real time operating systems (RTOS) that are utilized as infrastructure to create digital control systems for mechatronics systems, and also for systems that have critical time constraints. Parameters like worst case response time and interrupt latency were measured for each operating system. This research project also covers the implementation and use of RTOS in practical situations. A general research platform for robotics and real time research was also developed and will be used for future works in the Mechatronics Laboratory. The tested systems were VxWorks, QNX, Linux, RTAI, Windows XP, Windows CE and \'mü\'C/OS-II. Another product released during this work was a Live CD to aid the implementation and teaching of real time systems and concepts.
125

A performance and installation research in web server solutions for small e-commerce systems. / En prestanda och installations forskning i webb server lösningar för mindre e-handel system.

Shirazi, Erfan, Håkansson, Mattias, Abels, Christian January 2004 (has links)
This thesis investigates two different web server solutions. One is a commercial, proprietary solution known as the Windows solution that consists of Windows Server 2003, IIS and ASP. The other is a free, open source solution consisting of FreeBSD, Apache and PHP. The both solutions had the database MySQL as a common component. The hypothesis that was used in this investigation is as follows: IIS on Windows Server is not better than Apache on FreeBSD for e-commerce systems. To answer the hypothesis two empirical comparisons were conducted. One was a response time experiment testing two symmetrical web shops developed for the both solutions. For this response time test a stress test application was developed. The second comparison was a case study in the ease of installation of the two different solutions. The third empirical research method was a survey that was conducted among Swedish web hotel administrators. The survey identifies various factors that play a part when choosing one of the solutions. Open source users prefer performance, security and costs of software while Windows users prefer required knowledge, usability and compatibility. By analysing our result it is shown that the hypothesis is verified proving that an open source solution reports better performance because it has lower response times than the Windows solution. The results from the case study show that Windows is the easiest solution to install. / Den här uppsatsen undersöker två olika webbservrar lösningar. En är kommersiell patentskyddad lösning känd som Windows lösningen som består av Windows Server 2003, IIS och ASP. Den andra lösningen är en gratis open source lösning som består av FreeBSD, Apache och PHP. Båda lösningarna har databasen MySQL som en jämensam komponent. Hypotesen som användes i denna forskning är; IIS på Windows Server är inte bättre än Apache på FreeBSD för e-handel system. För att kunna besvara hypotesen gjordes två empirisk jämförelsen. En var respons tid experiment som testade två symmetriska webb shops som var utvecklad av oss för bägge lösningarna. För detta experiment utvecklades en stress test program. Den andra jämförelsen var en fallstudie i lätthet av installation av dessa två lösningar. Den tredje forsknings metoden är en undersökning bland svensk webb hotell administratörer. Undersökningen identifierar olika faktorer som spelar roll när man väljer en av lösningarna. Open source användare föredrar prestanda, säkerhet och kostnad av mjukvara medan Windows användare föredrar obligatorisk kunskap, användbarhet och jämförbarhet. Genom analys av våra resultat har vi visat att vår hypotes är verifierad och detta bevisar att open source lösningen har bättre prestanda genom att den har lägre respons tid än Windows lösningen. Resultatet av fallstudien visar att Windows är lättare att installera.
126

Automaticity in L2 learning: Correlation between vocabulary proficiency and response time in word recognition

Jonsson, Signe January 2016 (has links)
Automaticity (in this essay defined as short response time) and fluency in language use are closely connected to each other and some research has been conducted regarding some of the aspects involved. In fact, the notion of automaticity is still debated and many definitions and opinions on what automaticity is have been suggested (Andersson,1987, 1992, 1993, Logan, 1988, Segalowitz, 2010). One aspect that still needs more research is the correlation between vocabulary proficiency (a person’s knowledge about words and ability to use them correctly) and response time in word recognition. Therefore, the aim of this study has been to investigate this correlation using two different tests; one vocabulary size test (Paul Nation) and one lexical decision task (SuperLab) that measures both response time and accuracy. 23 Swedish students partaking in the English 7 course in upper secondary Swedish school were tested. The data were analyzed using a quantitative method where the average values and correlations from the test were used to compare the results. The correlations were calculated using Pearson’s Coefficient Correlations Calculator. The empirical study indicates that vocabulary proficiency is not strongly correlated with shorter response times in word recognition. Rather, the data indicate that L2 learners instead are sensitive to the frequency levels of the vocabulary. The accuracy (number of correct recognized words) and response times correlate with the frequency level of the tested words. This indicates that factors other than vocabulary proficiency are important for the ability to recognize words quickly.
127

Service Level Achievments - Test Data for Optimal Service Selection

Russ, Ricardo January 2016 (has links)
This bachelor’s thesis was written in the context of a joint research group, which developed a framework for finding and providing the best-fit web service for a user. The problem of the research group lays in testing their developed framework sufficiently. The framework can either be tested with test data produced by real web services which costs money or by generated test data based on a simulation of web service behavior. The second attempt has been developed within this scientific paper in the form of a test data generator. The generator simulates a web service request by defining internal services, whereas each service has an own internal graph which considers the structure of a service. A service can be atomic or can be compose of other services that are called in a specific manner (sequential, loop, conditional). The generation of the test data is done by randomly going through the services which result in variable response times, since the graph structure changes every time the system has been initialized. The implementation process displayed problems which have not been solved within the time frame. Those problems are displaying interesting challenges for the dynamical generation of random graphs. Those challenges should be targeted in further research.
128

Effects of conventionality and proficiency in metaphor processing : A response time study

Eriksson, Peter January 2013 (has links)
Some researchers that work with metaphor theory claim that metaphors and figurative language are understood and processed just as easily as literal language. However, as this thesis will explore in detail, other research indicates that such is not always the case. That is, if the category of metaphor is further subcategorized into conventional and non-conventional metaphor, the scope will change because of the fact that it is possible to argue that non-conventionalized metaphors require a more conscious path of processing. In order to explain this alternative path, there are two primary approaches to language processing worth introducing: implicit and explicit. These approaches vary in required attention and speed of processing. With regards to conscious effort, these approaches are rather similar to the way in which we process conventionalized and non-conventionalized metaphors. Conventional metaphors are processed more quickly and easily than non-conventional ones. Hence, the claim that all metaphors are similarly processed may not always be true. Furthermore, an individual’s level of proficiency presumably correlates with speed in language processing. However, if non-conventional metaphor requires a more deliberate path of processing, this thesis assumes that the processing of this type of metaphor will be relatively unaffected by proficiency level, thus causing informants to process them in similar manners. In this thesis, 24 non-native speakers (NNS), categorized into intermediate proficient and advanced proficient, and seven native speakers (NS) were tested with an RT-test on subjective metaphor comprehension. Results were compared using mean response times and standard deviations, as well as looking at correlations and coefficient of variation. The results showed a distinct difference in processing speed with conventional metaphors being processed significantly faster. Moreover, the findings indicate that conventional metaphor processing speed seems to be predicted by proficiency, whilst non-conventional processing speed is not. The RT differences remained relatively consistent in both conventional and non-conventional metaphor processing, but when taking correlations, variance and coefficient of variation into consideration, the findings indicate that these other factors help level out the differences in non-conventional metaphor processing in more subtle ways than simply by RT’s.
129

Datainsamling med Web Usage Mining : Lagringsstrategier för loggning av serverdata / Data Collection with Web Usage Mining : Storage strategies for logging server side data

Karlsson, Sophie January 2014 (has links)
Webbapplikationers komplexitet och mängden avancerade tjänster ökar. Loggning av aktiviteter kan öka förståelsen över användares beteenden och behov, men används i för stor mängd utan relevant information. Mer avancerade system medför ökade krav för prestandan och loggning blir än mer krävande för systemen. Det finns behov av smartare system, utveckling inom tekniker för prestandaförbättringar och tekniker för datainsamling. Arbetet kommer undersöka hur svarstider påverkas vid loggning av serverdata, enligt datainsamlingsfasen i web usage mining, beroende på lagringsstrategier. Hypotesen är att loggning kan försämra svarstider ytterligare. Experiment genomförs där fyra olika lagringsstrategier används för att lagra serverdata med olika tabell- och databasstrukturer, för att se vilken strategi som påverkar svarstiderna minst. Experimentet påvisar statistiskt signifikant skillnad mellan lagringsstrategierna enligt ANOVA. Lagringsstrategi 4 påvisar bäst effekt för prestandans genomsnittliga svarstid, jämfört med lagringsstrategi 2 som påvisar mest negativ effekt för den genomsnittliga svarstiden. Framtida arbete vore intressant för att stärka resultaten. / Web applications complexity and the amount of advanced services increases. Logging activities can increase the understanding of users behavior and needs, but is used too much without relevant information. More advanced systems brings increased requirements for performance and logging becomes even more demanding for the systems. There is need of smarter systems, development within the techniques for performance improvements and techniques for data collection. This work will investigate how response times are affected when logging server data, according to the data collection phase in web usage mining, depending on storage strategies. The hypothesis is that logging may degrade response times even further. An experiment was conducted in which four different storage strategies are used to store server data with different table- and database structures, to see which strategy affects the response times least. The experiment proves statistically significant difference between the storage strategies with ANOVA. Storage strategy 4 proves the best effect for the performance average response time compared with storage strategy 2, which proves the most negative effect for the average response time. Future work would be interesting for strengthening the results.
130

Transistor silicium en couche mince à base de nano-particules de PbS : un efficace phototransistor pour la détection de lumière infrarouge / Silicon thin film transistor based on PbS nano-particles : an efficient phototransistor for the detection of infrared light

Liu, Xiang 27 December 2016 (has links)
Le phototransistor est un nouveau type de photo-détecteur avec une structure MOSFET spéciale qui peut non seulement convertir la lumière absorbée en variation de courant, mais également auto-amplifier ce photo-courant. En particulier, avec des progrès continus dans la synthèse des points Quantum Dots (QDs), les caractères optiques et électriques uniques renforcent le coefficient d'absorption et la génération des trous d'électrons par des processus intégrés faciles. Dans cette thèse, on a synthétisé les PdS infrarouges PbS avec une large absorption infrarouge (IR) (600-1400 nm) et un rendement élevé pour être mélangés avec l'isolateur de porte SU8 des TFT à faible température de poly-silicium (LTPS). Grâce à l'utilisation de cet isolateur de porte photo-sensoriel hybride, ces LTPS TFT peuvent encore obtenir d'excellentes performances électriques telles qu'une mobilité suffisante (3.1 cm2 / Vs), des caractères TFT stables, un rapport marche / arrêt raisonnable (104 ~ 105) et une tension sous-seuil /Déc). De plus, en cas d'exposition à la lumière infrarouge incidente, la sensibilité élevée (1800 A/W) et la sensibilité non négligeable (13 A/W) se trouvent respectivement à 760 nm et 1300 nm. De plus, la photosensibilité atteint également jusqu'à 80 et le temps de réponse est d'environ 30 ms pendant un balayage du signal IR pulsé. Elle prend des mesures concrètes pour l'application générale du phototransistor IR. / Phototransistor is a novel type of photodetector with special MOSFET structure which can not only convert absorbed light into variation of current but also self-amplify this photocurrent. Especially, with continual advances in quantum dots' (QDs) synthesis, the unique optical-electrical characters reinforce absorption coefficient and electron-hole's generation by easy integrated processes. In this thesis, the infrared PbS QDs with wide infrared (IR) absorption (600-1400 nm) and high efficiency were synthesized to be blended with SU8 gate insulator of Low-Temperature-Poly-Silicon (LTPS) TFTs. Through using this hybrid photo-sensing gate insulator, this LTPS TFTs can still obtain excellent electrical performance such as enough mobility (3.1 cm2/Vs), stable TFT's characters, reasonable on/off ratio (104~105) and subthreshold voltage (3.2 V/Dec). Moreover, under incident IR light's exposure, the high responsivity (1800 A/W) and not negligible responsivity (13 A/W) can be found at 760 nm and 1300 nm respectively. In addition, the photosensitivity also reaches up to 80 and the response time is approximately 30 ms during a pulsed IR signal's scanning. It takes concrete steps forward for the broad application of IR phototransistor.

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