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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.
21

Validating Integrated Human Performance Models Involving Time-critical Complex Systems

Gore, Brian 29 April 2010 (has links)
The current research sets out to demonstrate a comprehensive approach to validate complex human performance models as applied to time-sensitive tasks. This document is divided into 4 sections. Section 1 (Chapters 1 – 3) outlines previous efforts in the literature that have attempted to validate complex human performance models in the field with an emphasis on manual control models, task network models, cognitive models and integrated architectures. Section 2 (Chapters 4 – 7) elaborates on a validation approach and applies it to a baseline model of a complex task in the air traffic control domain. Section 3 (Chapters 7-12) outlines the importance of adopting an iterative model development-model validation process and reports on the three model iterations in an attempt to improve the validity of the baseline model. Each model augmentation was validated using the same validation approach and measures that were defined in Section 2. Section 4 (Chapters 13-14) provides a discussion and interpretation of the model results and highlights contributions to the field of both model validation and the field of human performance modelling of complex systems.
22

Probabilistic performance model for evaluation of a smart work zone deployment

Bushman, Robert James 19 March 2007 (has links)
A safe and efficient highway infrastructure is a critical component and a valuable asset in terms of its monetary value, as well as supporting the way of life and economic activities of the people it serves. In North America, performing maintenance, repair, and expansion of an aging highway infrastructure to a target level of performance while dealing with ever-increasing traffic demands creates a significant challenge in terms of road user safety and mobility. Much of the current highway infrastructure was built several decades ago and it is therefore requiring increasing levels of maintenance and rehabilitation. <p>The cost of delays resulting from traffic congestion induced by work zones is estimated to be more than $6 billion per year. Work zone related traffic fatalities exceed more than 1000 lost lives per year in North America. Work zone related fatalities account for approximately 2.8 percent of highway fatalities in United States and 1.3 percent in Canada. While overall fatal crash rates have been steadily decreasing in both Canada and United States, work zone related fatalities have not been decreasing. <p>Smart Work Zones are an emerging technology designed to improve the safety and mobility within work zones on highways. Smart Work Zones employ various technologies to monitor current traffic conditions and provide relevant information to road managers and road users on current traffic flow conditions and automatically provide guidance to motorists for safer and more efficient navigation of the work zone. <p>This research examined the effects of a Smart Work Zone deployment by modeling traffic flow with and without a Smart Work Zone at the case study site in North Carolina to provide inputs into a performance analysis framework. The quantification of benefits and costs related to the deployment of a Smart Work Zone was developed in a probabilistic analysis framework model. The performance was quantified in economic terms of expected benefit cost ratio and net value realized from the deployment of a Smart Work Zone. The model considers the cost of deployment and potential savings in terms of motorist safety (fatal and injury crash reduction) as well as improvements in traveler mobility including reductions in user delays, vehicle operating costs, and emissions.<p>The model output is a risk profile that provides a range of expected values and associated probabilities of occurrence to quantify the expected benefits while also taking into consideration the uncertainty of the most sensitive input variables. The uncertainty of input variables determined to be the most sensitive were those associated with the amount of user delay and the valuation of user delay. The next most sensitive inputs are those associated with the cost of deploying and operating the Smart Work Zone system. <p>The model developed in this research concurs with the approach and analysis used in other models for the analysis of transportation projects. The model developed in this research provides a tool that can be used for decision making regarding the deployment of a Smart Work Zone and comparison with other transportation project alternatives. The model employs a user definable approach that enables it to be adapted to the specific conditions of a diverse range of field state conditions and has the ability to interface with several traffic flow models. <p>When applied to a case study project on Interstate 95 in North Carolina, the model was found to be capable of providing useful and relevant results that correlated to observed performance. The case study represented one of many operating scenarios on the project, and is not necessarily representative of all the field state conditions occurring over the period of the entire deployment. <p>The model results included a sensitivity analysis that identified the sensitivity of the outcome to uncertainty in the input values and a risk analysis that quantified the uncertainty of the predictions. The findings indicated that, at a 95 percent confidence level, the expected benefit / cost ratio of deploying a Smart Work Zone system was between 1.2 and 11.9 and the net value was between $10,000 and $225,000 per month of operation. Approximately 94 percent of the expected benefits were from savings in user delay and the remainder from savings due to improved safety, reduced emissions, and reduced vehicle operating costs. The results indicate that when applied under appropriate conditions, Smart Work Zones have the potential to provide significant benefits to road users. Under heavily congested conditions, the diversion of even a small amount of traffic to a more efficient route can provide sizable travel time improvements for all traffic.<p>In summary, the model developed in this research was specifically developed to apply to Smart Work Zones, but in its general form could also be applied to other work zone traffic management applications. In the case study the model was applied to a single rural work zone, but the framework could be extended for an integrated analysis of multiple work zones and network analysis in an urban setting. The research provides a fundamental framework and model for the analysis of Smart Work Zones and a method to determine the sensitivity of the uncertainty of input values. The research also identifies areas for continued examination of the effects of Smart Work Zone deployment and the prediction of expected benefits.
23

A programming model and performance model for cycle stealing

Sumitomo, Jiro January 2006 (has links)
This work describes a programming model and performance model for cycle stealing on the Internet. Cycle stealing is the use of otherwise idle computers to perform work, and promises high performance computing at relatively low cost. The Internet, being the largest pool of potentially idle computers, is an obvious target for cycle stealing. However, computers connected to the Internet are often protected by firewalls, preventing point-to-point communication between them. The fluctuating avail-ability of computers for cycle stealing as they move in and out of an idle state, combined with the restricted communication of the Internet environment, means that programming models and abstractions suitable for programming supercom-puters and clusters are not ideal. Therefore, I have created a programming model for cycle stealing which reflects the types of parallel applications that are suitable for execution using idle computers connected to the Internet. The model is de-signed for use by non-expert parallel programmers, and I will show how it simpli-fies the development of cycle stealing applications, enabling rapid application de-velopment, and straightforward porting of existing sequential applications. This simple to use programming model, combined with the low cost of cycle stealing, improves the accessibility of high performance computing to non-traditional us-ers of supercomputers and clusters. Deployment on the Internet, and the need to navigate through firewalls, suggests a web based framework using common web protocols, web servers and web browsers. Part of this work investigates the feasibility of web based approaches to cycle stealing, from the setup of a cycle stealing system, application development and deployment, and connection of potentially idle computers. I designed and implemented a cycle stealing framework, deployable on the web, to meet expec-tations of performance, reliability, ease of use and safety. Existing cycle stealing frameworks emphasise the need for applications to be de-composed into a set of jobs that execute for a long period, that is, a job should have a computation time sufficient to justify its communication cost. However, there are no tools available for users to determine what an appropriate computa-tion time might be, given a job's data communication requirements. To date, de-ciding the granularity of jobs has been a matter of intuition. Therefore, a user may experience uncertainty as to the benefit of cycle stealing for their particular application, especially if the applications will have relatively short-lived jobs. Based on performance analysis of my framework, I have developed an analytical model and simulator, which can be used to predict, and help to optimise, the per-formance of user applications, and show the feasibility of executing a particular application using the cycle stealing framework.
24

Návrh modelu měření a hodnocení výkonnosti příspěvkových organizací. / The Design of the Model for Funded Organization Performance Measurement and Assessment

ŠULC, Michal January 2014 (has links)
The subject of this dissertation thesis is the performance of funded organizations, specifically the Czech region-founded museums. The main goal of the author is to design a model for regional museum performance measurement and assessment. The designed model is called the performance pyramid due to hierarchical layout of its elements. The model is horizontally divided into four levels, namely resources management, programs realization, functions fulfilment and mission realization. Each of the model levels consists of typical elements that can be modified or changed in order to meet the needs and specifics of each particular museum. The elements and relations between them are measured and assessed by means of performance indicators. These are, according to the model level, called inputs, outputs and outcomes indicators. The relations between the particular elements are the performance dimensions. The model distinguishes dimensions of economy, efficiency, productivity, quality and effectiveness. The model construction has been verified at the Museum Vysočiny Jihlava.
25

Power-Performance Modeling and Adaptive Management of Heterogeneous Mobile Platforms​

January 2018 (has links)
abstract: Nearly 60% of the world population uses a mobile phone, which is typically powered by a system-on-chip (SoC). While the mobile platform capabilities range widely, responsiveness, long battery life and reliability are common design concerns that are crucial to remain competitive. Consequently, state-of-the-art mobile platforms have become highly heterogeneous by combining a powerful SoC with numerous other resources, including display, memory, power management IC, battery and wireless modems. Furthermore, the SoC itself is a heterogeneous resource that integrates many processing elements, such as CPU cores, GPU, video, image, and audio processors. Therefore, CPU cores do not dominate the platform power consumption under many application scenarios. Competitive performance requires higher operating frequency, and leads to larger power consumption. In turn, power consumption increases the junction and skin temperatures, which have adverse effects on the device reliability and user experience. As a result, allocating the power budget among the major platform resources and temperature control have become fundamental consideration for mobile platforms. Dynamic thermal and power management algorithms address this problem by putting a subset of the processing elements or shared resources to sleep states, or throttling their frequencies. However, an adhoc approach could easily cripple the performance, if it slows down the performance-critical processing element. Furthermore, mobile platforms run a wide range of applications with time varying workload characteristics, unlike early generations, which supported only limited functionality. As a result, there is a need for adaptive power and performance management approaches that consider the platform as a whole, rather than focusing on a subset. Towards this need, our specific contributions include (a) a framework to dynamically select the Pareto-optimal frequency and active cores for the heterogeneous CPUs, such as ARM big.Little architecture, (b) a dynamic power budgeting approach for allocating optimal power consumption to the CPU and GPU using performance sensitivity models for each PE, (c) an adaptive GPU frame time sensitivity prediction model to aid power management algorithms, and (d) an online learning algorithm that constructs adaptive run-time models for non-stationary workloads. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018
26

Extração de informações de desempenho em GPUs NVIDIA / Performance Information Extraction on NVIDIA GPUs

Paulo Carlos Ferreira dos Santos 15 March 2013 (has links)
O recente crescimento da utilização de Unidades de Processamento Gráfico (GPUs) em aplicações científicas, que são voltadas ao desempenho, gerou a necessidade de otimizar os programas que nelas rodam. Uma ferramenta adequada para essa tarefa é o modelo de desempenho que, por sua vez, se beneficia da existência de uma ferramenta de extração de informações de desempenho para GPUs. Este trabalho cobre a criação de um gerador de microbenchmark para instruções PTX que também obtém informações sobre as características do hardware da GPU. Os resultados obtidos com o microbenchmark foram validados através de um modelo simplificado que obteve erros entre 6,11% e 16,32% em cinco kernels de teste. Também foram levantados os fatores de imprecisão nos resultados do microbenchmark. Utilizamos a ferramenta para analisar o perfil de desempenho das instruções e identificar grupos de comportamentos semelhantes. Também testamos a dependência do desempenho do pipeline da GPU em função da sequência de instruções executada e verificamos a otimização do compilador para esse caso. Ao fim deste trabalho concluímos que a utilização de microbenchmarks com instruções PTX é factível e se mostrou eficaz para a construção de modelos e análise detalhada do comportamento das instruções. / The recent growth in the use of tailored for performance Graphics Processing Units (GPUs) in scientific applications, generated the need to optimize GPU targeted programs. Performance models are the suitable tools for this task and they benefits from existing GPUs performance information extraction tools. This work covers the creation of a microbenchmark generator using PTX instructions and it also retrieves information about the GPU hardware characteristics. The microbenchmark results were validated using a simplified model with errors rates between 6.11% and 16.32% under five diferent GPU kernels. We also explain the imprecision factors present in the microbenchmark results. This tool was used to analyze the instructions performance profile, identifying groups with similar behavior. We also evaluated the corelation of the GPU pipeline performance and instructions execution sequence. Compiler optimization capabilities for this case were also verified. We concluded that the use of microbenchmarks with PTX instructions is a feasible approach and an efective way to build performance models and to generate detailed analysis of the instructions\' behavior.
27

Performance Modeling of ASP.Net Web Service Applications: an industrial case study

de Gooijer, Thijmen January 2011 (has links)
During the last decade the gap between software modeling and performancemodeling has been closing. For example, UML annotations have been developed to enable the transformation of UML software models to performance models, thereby making performance modeling more accessible. However, as of yet few of these tools are ready for industrial application. In this thesis we explorer the current state of performance modeling tooling, the selection of a performance modeling tool for industrial application is described and a performance modeling case study on one of ABB's remote diagnostics systems (RDS) is presented. The case study shows the search for the best architectural alternative during a multi-million dollar redesign project of the ASP.Net web services based RDS back-end. The performance model is integrated with a cost model to provide valuable decision support for the construction of an architectural roadmap. Despite our success we suggest that the stability of software performance modeling tooling and the semantic gap between performance modeling and software architecture concepts are major hurdles to widespread industrial adaptation. Future work may use the experiences recorded in this thesis to continue improvement of performance modeling processes and tools for industrial use.
28

Hodnocení výkonnosti společnosti Envinet a.s. podle modelu Start Plus / Company Performance Assessment of Envinet LTD. according to Model Start Plus

Brejchová, Ingrid January 2015 (has links)
This diploma thesis deals with the company performance assessment of the selected organization. The described organization is called ENVINET Inc. and it is analyzed according to multi-criteria model START PLUS. According to this model, the final point assessment of the company is realised, strengths and weaknesses and areas for improvement are identified. There are also proposed specific measures whose implementation can improve the performance of the analyzed company.
29

Model Adaptation of a Mixed Flow Turbofan Engine

Lindkvist, Oskar January 2020 (has links)
Gas turbine performance models are usually created in an object oriented manner, where different standard components are connected to form the complete model. The characteristics of these components are often represented by component maps and empirical correlations. However, engine specific component characteristics are seldom available to anyone outside of the manufacturers. It is therefore very common for researchers to use publicly accessible or generic component maps instead. But in order to reduce prediction errors the maps have to be modified to fit any specific engine. This thesis work investigates the process of adapting a parametric turbofan engine model to a limited amount of test-data using the propulsion program EVA. Steady state test-data was generated using an initial reference model with SLS operating conditions. Another engine model with different fan, compressor and turbine maps was then used in the adaptation. An initial on-design model was adapted to the highest power test-data point. This model is based on aerothermodynamic equations and is used as a reference to scale the generic component maps to. A sensitivity analysis was done at this point in order to find dependencies between unknown component parameters and test data. These were then included in the cycle solver which employs a version of the Newton-Raphson method. After the fan and compressor maps had been scaled to the design point they were adapted to test-data by adjusting the mass flow parameters in a direct search optimizer. Finally, speed lines in the fan and compressor maps were relabeled to reduce rotor speed errors. The adapted performance model was then validated against the reference model at a few flying conditions. The performance model results demonstrate that it is possible to greatly reduce prediction errors by only adjusting the corrected mass flow in fan and compressor maps. Additionally, rotor speed errors could successfully be corrected as a final step in the adaptation by relabeling speed lines in the component maps. When validated, the adapted model had a maximum parameter error of 1.5%.
30

Occupational performance and social participation of children with cerebral palsy : A scoping review

Šunjerga, Nada January 2023 (has links)
Introduction: Social participation (SP) of children with cerebral palsy (CP) may be limited by various factors. Domains of occupational therapy were within the Person-Environment-Occupation-Performance (PEOP) model. Aim: The study aim was to identify the literature regarding the impact of occupational performance on the social participation of children with cerebral palsy. Method: A scoping review explored peer-reviewed and grey literature from 2013-2023 to incorporate data/experiences via search databases, internet search engines blogs/websites, and manual searches. The inclusion criteria were participants with CP aged 10-18. Data analysis was carried out through qualitative content analysis. Findings: Twenty-nine articles and 14 blogs/websites were included. The impairment's severity and environmental factors emphasizing the parental role and income were prominent influences on OP and SP. The importance of social support was highlighted through experiences presented in grey literature. The themes aligned with the categories of the PEOP model, where a mismatched category occurred, related to sexuality. Conclusion: This review pointed out the factors that influence OP and SP presented based on the categories of the PEOP model, including the mismatched category. Significance: The importance of the representative role of occupational therapy was emphasized. The results indicated future research recommendations based on school type and sexuality.

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