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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.
311

Certification of static analysis in many-sorted first-order logic / Analyse statique certifiée en logique du premier ordre multi-sortée

Cornilleau, Pierre-Emmanuel 25 March 2013 (has links)
L'analyse statique est utilisée pour vérifier de manière formelle qu'un programme ne fait pas d'erreurs, mais un analyseur statique est lui même un programme complexe sujet aux erreurs. Une analyse statique formalisée comme un interpreteur abstrait peut être prouvée correcte, cependant un telle preuve ne porte pas directement sur l'implementation de l'analyseur. Pour résoudre cette difficultée, nous proposons de générer des conditions de vérification (VCs, des formules logiques valides seulement si le résultat de l'analyseur est correct), et de les décharger à l'aide d'un prouveur de théorèmes automatique (ATP). Les VCs générées appartiennent à la logic du premier ordre multi-sortée (MSFOL), une logique utilisée avec succés en vérification déductive, suffisament expressive pour encoder les résultats d'analyses complexes et pour formaliser la sémantique operationnelle d'un langage objet, ce qui nous permet de prouver la correction des VCs générées à l'aide d'outils de vérification deductive. Pour assurer que les VCs puissent être déchargée automatiquement pour des analyses du tas, nous introduisons un calcul de VCs appartenant à un fragment décidable de MSFOL, et afin de pouvoir utiliser le même calcul pour différentes analyses, nous décrivons une famille d'analyses à l'aide d'une fonction de concretisation et d'un instrumentation de la sémantique paramétrées. Pour améliorer la fiabilité des ATPs, nous étudions aussi la certification de résultat des proveurs de satisfiabilité modulo théories, une famille d'ATPs dédiée à MSFOL. Nous proposons un système de preuve et un vérifieur modulaires, qui s'appuient sur des vérifieur dédiés aux théories sous-jacentes. / Static program analysis is a core technology for both verifying and finding errors in programs but most static analyzers are complex pieces of software that are not without error. A Static analysis formalised as an abstract interpreter can be proved sound, however such proofs are significantly harder to do on the actual implementation of an analyser. To alleviate this problem we propose to generate Verification Conditions (VCs, formulae valid only if the results of the analyser are correct) and to discharge them using an Automated Theorem Prover (ATP). We generate formulae in Many-Sorted First-Order Logic (MSFOL), a logic that has been successfully used in deductive program verification. MSFOL is expressive enough to describe the results of complex analyses and to formalise the operational semantics of object-oriented languages. Using the same logic for both tasks allows us to prove the soundness of the VC generator using deductive verification tools. To ensure that VCs can be automatically discharged for complex analyses of the heap, we introduce a VC calculus that produces formulae belonging to a decidable fragment of MSFOL. Furthermore, to be able to certify different analyses with the same calculus, we describe a family of analyses with a parametric concretisation function and instrumentation of the semantics. To improve the reliability of ATPs, we also studied the result certification of Satisfiability Modulo Theory solvers, a family of ATPs dedicated to MSFOL. We propose a modular proof-system and a modular proof-verifier programmed and proved correct in Coq, that rely on exchangeable verifiers for each of the underlying theories.
312

Kinematická analýza elitních lezců v soutěžní cestě Českého poháru ve sportovním lezení na obtížnost / Time-motion analysis of elite Czech sport climbers during Czech Lead Climbing Cup

Ježková, Ludmila January 2019 (has links)
Title: A time motion analysis of lead climbing of elite climbers in the competition route of Czech Cup. Objectives: The aim of this works is to perform time motion analysis of lead climbing of elite climbers in the competition route of Czech Cup. Methods: Data were collected by video recording. Observation criteria were set (total time, holding, quickdraw clipping, rest and chalking). 8 climbers were measured on the 10- UIAA difficulty route. Results: The average climbing time was 203 ± 32,6 s, the average holding time was 7,1 ± 0,8 s (total 161,3 ± 29,2 s), the average rets period was 1,2 ± 0,4 s (total 6,5 ± 3,3 s), the average quickdraw clipping time was 2,3 ± 0,4 s (total 24,9 ± 4,6 s), the average chalking time was 2,1 ± 0,6 s (total 16 ± 3,7 s) and the average hand-transfer time was 0,9 ± 0,2 s (total 38,4 ± 9,1 s). Climbers climbed 4,8 meters per minute. Conclusions: The static part almost four times prevails the dynamic part. There were no significant differences between right and left hand in our measurements. Keywords: holding, loading, rest, static phase, dynamic phase
313

The Effect of Deposition from Static Rocket Tests on Immature Corn, Alfalfa, and Winter Wheat

Curry, Eric 01 May 2015 (has links)
Orbital ATK tests horizontally restrained solid rocket motors (SRMs) in Promontory, Utah, USA. During SRMs tests, an estimated 1.5 million kg (~3.3 million lbs.) of entrained soil and combustion products (mainly aluminum oxide, gaseous hydrogen chloride, and water) are deposited over a wide area. Local farmers have expressed concerns regarding the deposition of this material, referred to as Test Fire Soil (TFS), on crops surrounding the test site. Greenhouse studies of mature corn and alfalfa (54 days to harvest) exposed to a worse case TFS deposition density to soil (3200-g/m2) resulted in reductions in germination and plant growth. Application of TFS only on leaves caused visual changes in leaf appearance (e.g. “burning”) but did not impact on growth. The visual damage to the leaves was thought to be caused by the high chloride in the TFS. The pH (measured from 2-10 in the field) of the TFS was also thought to be a potential cause of the visual damage. Follow-up studies were conducted using younger corn, alfalfa and winter wheat (12-54 days from emergence), to evaluate the impact of a more typical TFS deposition density and application scenario. The relationship between deposition amount and the crop impact was also examined. Impact was evaluated by comparing the growth, tissue composition (focusing on chloride and aluminum) and chlorophyll content of controls relative to the treatments. The individual effects of chloride and pH on corn leaves were determined by monitoring visual appearance and chlorophyll content. Leaves exposed to a typical TFS deposition loading (70-g/m2) did not contain elevated chloride or aluminum levels relative to the controls. Higher TFS loadings (700-g/m2 and 3200-g/m2) resulted in significantly elevated chloride content in corn leaves at 29 days from emergence. Corn leaves treated with TFS at the 700-g/m2 loading 12 days from emergence had comparable chloride levels to controls. High and low pH and chloride solutions visually impacted corn leaves and reduced leaf chlorophyll. This study indicated SRMs testing can be conducted under typical conditions during the juvenile growth stages of field corn, alfalfa, and winter wheat without adverse impact on crop yield and plant tissue composition.
314

A Security Evaluation Methodology for Container Images

Abbott, Brendan Michael 01 March 2017 (has links)
The goal of this research is to create a methodology that evaluates the security posture of container images and helps improve container security. This was done by first searching for any guidelines or standards that focus on container images and security. After finding none, I decided to create an evaluative methodology. The methodology is composed of actions that users should take to evaluate the security of a container image. The methodology was created through in-depth research on container images and the build instructions used to create them and is referred to as the Security Evaluation Methodology for Container Images. The entire Methodology was reviewed by experts in containers, information technology, and security; updated based on their feedback; and then reviewed again for further feedback. Four of the most popular container images—nginx, redis, mbabineau/cfn-bootstrap, and google/cadvisor—were evaluated using the Methodology. The evaluation revealed security issues in each image and provided direction on how to resolve each issue. Based on the positive feedback of experts and the performance of the Methodology, I propose that the Methodology be used to evaluate all container images, as it provides valuable security insights about, and suggestions for, an image.
315

An analysis of posture, muscle activity and keyboard dynamics in computer users with and without work-related neck and upper limb disorders

Szeto, Pui Yuk Grace January 2003 (has links)
Computer technology has advanced rapidly in the past few decades and computers have become a very important and powerful tool in our everyday lives. Prolonged computer use by office workers has been reported to result in an increased risk of developing Work-related Neck and Upper Limb Disorders (WRNULD) (Bernard et al.. 1994: Faucett & Rempel. 1994: Tittiranonda et al.. 1999). The occupational risk factors associated with prolonged computer use include static posture and the speed and force of keyboard operation. Past studies have examined different aspects of these risk factors through measuring muscle electrical activity (EMG), kinematics and keyboard forces. However, most of these studies have been conducted on healthy painfree subjects and even the few Case-Control studies have not clearly established any direct relationships between the risk factors and WRNULD. The present research project consisted of a series of three studies aimed at investigating whether there were intrinsic differences among different individuals in response to different physical stressors. These intrinsic differences may have important implications to help explain why some individuals would develop WRNULD while others do not. The individuals' responses to the demands of three physical stressors: static posture, speed and force of keyboard operation were assessed. The internal exposure measures of kinematics, EMG, keyboard dynamics and subjective discomforts were used to evaluate the inter-individual differences. Study I was a field investigation comparing the neck-shoulder kinematics between symptomatic ("Case", n=8) and asymptomatic ("Control", n=8) office workers. Results showed trends for consistently greater head tilt and neck flexion angles, and greater ranges of movements in the Case Group than the Control Group. / The Case Group also exhibited a trend for increased acromion protraction compared to the Control Group. The Case Group also reported significantly greater discomfort scores compared to the Control Group. Neither the discomforts nor the kinematics displayed any significant changes over a working day. Study 2 was a laboratory study comparing the responses of Case and Control Groups in terms of EMG, kinematics and subjective discomforts, while a standardised computer task was performed continuously for one hour. The responses of Case (n=23) and Control (n=20) Groups were compared to examine the effects of static posture. The results showed similar trends to those in Study I, with increased neck flexion mean angles and ranges of movements in the Case Group compared to the Control Group. In terms of EMG results, there were trends for EMG amplitude differences in the right upper trapezius (UT) and cervical erector spinae (CES) muscles between Case and Control Groups. These trends became statistically significant when the Case subjects were sub-divided into the High (n=15) and Low (n=8) Groups based on their mean discomfort scores. Study 3 was also a laboratory study to compare the Case (n=21) and Control (n=20) Groups when they were challenged by the physical stressors of speed and force of keyboard operation. In this study, each subject's EMG and discomforts were examined in three typing conditions of normal speed and force, increased typing speed and increased typing force. The Case Group showed trends for higher increases in both UT and CES muscle activities than the Control Group, and when divided into the High-Low Groups, the High Group (n=8) showed trends for much higher muscle activities in all three conditions. / Beside muscle activity changes, the High Group subjects also demonstrated a trend for much higher within-subject Speed and Force Variabilities in their keystroke performance, compared to the Low Group and the Control Group. This result implied that the High Group subjects had a more erratic motor control of the keystroke actions. Based on these results, conceptual models were developed to describe the relationships among the physical stressors, internal exposure responses and discomforts. The Altered Motor Control Model refers to the programmed changes in motor control strategies involving muscle recruitment and joint movement patterns, and these changes were closely related to the subjects' musculoskeletal discomforts. The Heightened Sensitivity Model describes the higher sensitivity levels of individuals with more severe discomforts, in response to the demands of physical stressors. These models are closely related and heightened sensitivity may be an 'effect-modifier" of the motor control mechanisms and the perception of discomforts or pains within the individual. In conclusion, the present research has identified important differences between individuals on the basis of their motor control strategies which may contribute to the development of WRNULD. While the present research has mainly examined the individual responses to three physical stressors, it is possible that the models developed may be applicable to other physical stressors. These findings may also have important implications for future ergonomic research, emphasising the need to address interindividual differences in ergonomic interventions to workers. Further research should be directed towards better understanding of these intrinsic individual differences in both physical and non-physical factors that contribute to the development of WRNULD.
316

Self-Reliance Guidelines for Large Scale Robot Colonies

Engwirda, Anthony, N/A January 2007 (has links)
A Large Scale Robot Colony (LSRC) is a complex artifact comprising of a significant population of both mobile and static robots. LSRC research is in its literary infancy and it is therefore necessary to rely upon external fields for the appropriate framework, Multi Agent Systems (MAS) and Large Scale Systems (LSS). At the intersection of MAS, LSS and LSRC exist near identical issues, problems and solutions. If attention is paid to coherence then solution portability is possible. The issue of Self-Reliability is poorly addressed by the MAS research field. Disparity between the real world and simulation is another area of concern. Despite these deficiencies, MAS and LSS are perceived as the most appropriate frameworks. MAS research focuses on three prime areas, cognitive science, management and interaction. LSRC is focused on Self-Sustainability, Self-Management and Self-Organization. While LSS research was not primarily intended for populations of mobile robots, it does address key issues of LSRC, such as effective sustainability and management. Implementation of LSRC that is based upon the optimal solution for any one or two of the three aspects will be inferior to a coherent solution based upon all three. LSRC’s are complex organizations with significant populations of both static and mobile robots. The increase in population size and the requirement to address the issue of Self-Reliance give rise to new issues. It is no longer sufficient to speak only in terms of robot intelligence, architecture, interaction or team behaviour, even though these are still valid topics. Issues such as population sustainability and management have greater significance within LSRC. As the size of a robot populations increases, minor uneconomical decisions and actions inhibit the performance of the population. Interaction must be made economical within the context of the LSRC. Sustainability of the population becomes significant as it enables stable performance and extended operational lifespan. Management becomes significant as a mechanism to direct the population so as to achieve near optimal performance. The Self-Sustainability, Self-Management and Self-Organization of LSRC are vastly more complex than in team robotics. Performance of the overall population becomes more significant than individual or team achievement. This thesis is a presentation of the Cooperative Autonomous Robot Colony (CARC) architecture. The CARC architecture is novel in that it offers a coherent baseline solution to the issue of mobile robot Self-Reliance. This research uses decomposition as a mechanism to reduce problem complexity. Self-Reliance is decomposed into Self-Sustainability, Self-Management, and Self-Organization. A solution to the issue of Self-Reliance will comprise of conflicting sub-solutions. A product of this research is a set of guidelines that manages the conflict of sub-solutions and maintains a coherent solution. In addressing the issue of Self-Reliance, it became apparent that Economies of Scale, played an important role. The effects of Economies of Scale directed the research towards LSRC’s. LSRC’s demonstrated improved efficiency and greater capability to achieve the requirements of Self-Reliance. LSRC’s implemented with the CARC architecture would extend human capability, enabling large scale operations to be performed in an economical manner, within real world and real time environments, including those of a remote and hostile nature. The theory and architecture are supported using published literature, experiments, observations and mathematical projections. Contributions of this work are focused upon the three pillars of Self-Reliance addressed by CARC: Self-Sustainability, Self-Management and Self-Organization. The chapter on Self-Sustainability explains and justifies the relevance of this issue, what it is, why it is important and how it can be achieved. Self-Sustainability enables robots to continue to operate beyond disabling events by addressing failure and routine maintenance. Mathematical projections are used to compare populations of non-sustained and sustained robots. Computer modeling experiments are used to demonstrate the feasibility of Self-Sustainability, including extended operational life, the maintenance of optimal work flow and graceful physical degradation (GPD). A detailed explanation is presented of Sustainability Functions, Colony Sites, Static Robot Roles, Static Robot Failure Options, and Polymorphism. The chapter on Self-Management explores LSS research as a mechanism to exert influence over a LSRC. An experimental reactive management strategy is demonstrated. This strategy while limited does indicate promising potential directions for future research including the Man in the Loop (MITL) strategy highly desired by NASA JPL for off world command and control of a significant robot colony (Huntsberger, et. al., 2000). Experiments on Communication evaluate both Broadcast Conveyance (BC) and Message Passing Conveyance (MPC). These experiments demonstrate the potential of Message Passing as a low cost system for LSRC communication. Analysis of Metrics indicates that a Performance Based Feedback Method (PBFM) and a Task Achievement Method (TAM) are both necessary and sufficient to monitor a LSRC. The chapter on Self-Organization describes a number of experiments, algorithms and protocols on Reasoning Robotics, a minor variant of Reactive Robotics. Reasoning Robotics utilizes an Event Driven Architecture (EDA) rather than a Stimulus Driven Architecture (SDA) common to Reactive Robotics. Enhanced robot performance is demonstrated by a combination of EDA and environmental modification enabling stigmergy. These experiments cover Intersection Navigation with contingency for Multilane Intersections, a Radio Packet Controller (RPC) algorithm, Active and Passive Beacons including a communication protocol, mobile robot navigation using Migration Decision Functions (MDF’s), including MDF positional errors. The central issue addressed by this thesis is the production of Self-Reliance guidelines for LSRC’s. Self-Reliance is perceived as a critical issue in advancing the useful and productive applications for LSRC’s. LSRC’s are complex with many issues in related fields of MAS and LSS. Decomposition of Self-Reliance into Self-Sustainability, Self-Management and Self-Organization were used to aid in problem understanding. It was found that Self-Sustainability extends the operational life of individual robots and the LSRC. Self-Management enables the exertion of human influence over the LSRC, such that the ratio of humans to robots is reduced but not eliminated. Self-Organization achieves and enhances performance through a routine and reliable LSRC environment. The product of this research was the novel CARC architecture, which consists of a set of Self-Reliance guidelines and algorithms. The Self-Reliance guidelines manage conflict between optimal solutions and provide a framework for LSRC design. This research was supported by literature, experiments, observations and mathematical projections.
317

Volatile compounds in some eastern Australian Banksia flowers

Tronson, Deidre A., University of Western Sydney, Hawkesbury, College of Science, Technology and Environment, School of Science, Food and Horticulture January 2001 (has links)
This project was the very beginning of research into the chemistry of eastern Australian banksia flowers. Using dynamic headspace sampling (DHS) analysis, differences in volatile components, consistent with detection of differences in odour, were detected among three different species and one commercial cultivar. Infraspecific variation was also observed between two known subspecies of Banksia ericifolia and between differently coloured forms of Banksia spinulosa var. collina. The cultivar, Banksia 'Giant Candles', was shown to have some of the chemical components of each of its supposed ancestors. The absence of known wound-response chemicals indicated that this DHS method was successful in leaving the inflorescences undamaged throughout the sampling procedure. The Likens-Nickerson modification of classical hydrodistillation methods was useful. The static headspace method (SHS) was easily automated and was shown to be chemically robust and sufficiently sensitive to detect volatile compounds from only a few flowers. The milder DHS method, which minimised mechanical and heat damage to the plant tissue, produced a different set of results. From the results of this project, a suite of volatile compounds has been proposed that may be useful in future behavioural studies to help determine whether animals are attracted to components of banksia odours. These candidates include some compounds that have been reported in animal secretions, wound-response chemicals that may be produced by the plant to aid its communication with other organisms, and a compound (suggested to be sulfanylmethyl acetate) not previously reported from natural sources. The mildest of the three analytical methods used, dynamic headspace sampling, was shown to be suitable for the potential chemotaxonomic evaluation of some members of the Banksia genus. / Doctor of Philosophy (PhD)
318

Online Identification of Friction Coefficients in an Industrial Robot

Längkvist, Martin January 2009 (has links)
<p>All mechanical systems with moving parts are affected by friction, including industrial robots. Being able to design an accurate friction model would further increase the performance of todays robots. Friction is a complex dynamic phenomena that is constantly changing depending on the state and environment of the robot. It is therefore beneficial to update the parameters of the friction model online. An estimate of the friction will be made using the feedback control signal with the help of a feedforward control scheme in a two axis simulation setup. The friction estimate is then used for an offline identification of three friction model parameters in a static Lugre friction model. Improvements on the identification will be done by introducing some shut-off rules that will improve the estimate. The normalized least mean square method (NLMS) will then be used to update the parameters online. A simulation of friction compensation with a fixed friction model, and with an adaptive friction model will be studied. The method will also be simulated using experimental data taken from a real industrial robot.</p>
319

Investigation of typical 0.13 µm CMOS technology timing effects in a complex digital system on-chip

Johansson, Anders January 2004 (has links)
<p>This master's thesis deals with timing effects in complex on chip systems. It is written in cooperation with the research and development centre of Infineon Technologies. </p><p>One primary goal of all integrated circuit designers is to make the chips as small as possible. In deep sub micron designs timing effects like crosstalk have severe impact on the functionality of the chip. Therefore, accurate timing analyses must be made before the chip is ready for manufacturing. Otherwise the production yield can be reduced drastically. A case study on timing analysis with the 0.13 µm technology is made on the bus system of the device S-GOLD. </p><p>The computer-based program PrimeTime is used to carry out the timing analysis. During the evolution of 0.13 µm technology three design packages have been developed to characterize the timing. Two releases of SGOLD have been designed based on the first and the second design package. The different design packages were compared, with and without pin capacitance variations, on chip variations and crosstalk. Furthermore the two releases are compared. The result from the analysis tool may not correlate well with what you see on the manufactured chips. In order to investigate the correlation, some tests were finally performed on an evaluation board. </p><p>The results from the timing analysis are as expected. The second netlist version is better optimized than the first one. Design package three is most pessimistic among the three design packages. Design package one is most optimistic and does not match the real performance. Both design package two and three fit to the real performance well. Among the three design packages, design package three fits the real performance best.</p>
320

Modeling and Pattern Matching Security Properties with Dependence Graphs

Fåk, Pia January 2005 (has links)
<p>With an increasing number of computers connected to the Internet, the number of malicious attacks on computer systems also raises. The key to all successful attacks on information systems is finding a weak spot in the victim system. Some types of bugs in software can constitute such weak spots. This thesis presents and evaluates a technique for statically detecting such security related bugs. It models the analyzed program as well as different types of security bugs with dependence graphs. Errors are detected by searching the program graph model for subgraphs matching security bug models.</p><p>The technique has been implemented in a prototype tool called GraphMatch. Its accuracy and performance have been measured by analyzing open source application code for missing input validation vulnerabilities. The test results show that the accuracy obtained so far is low and the complexity of the algorithms currently used cause analysis times of several hours even for fairly small projects. Further research is needed to determine if the performance and accuracy can be improved.</p>

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