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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.
101

Effects of Pay Variability and Mutual Monitoring on Employee Effort and Contract Choice

Mortenson, Kristian G January 2008 (has links)
A primary cause of income volatility for employees is job loss due to firm downsizing. Economists have suggested that firms use share contracts rather than wage contracts as one possible solution to downsizing. In my experimental setting employment contracting involves an employer who hires two employees to produce output. In each of 31 rounds, employees choose between a wage contract (status quo) and a share contract with an employer-set sharing rule. I manipulate whether the share contract incorporates a form of mutual monitoring and examine the effects on employee effort, contract preference, and welfare. The results show that, compared to wage contracts, subjects exert more effort and have higher welfare when they choose share contracts. Incorporating mutual monitoring into the share contract also increases total effort and subject welfare but does not lead to an increase in the use of share contracts.
102

Privacy Monitoring and Enforcement in a Web Service Architecture (WSA)

Tong, Kai 03 May 2012 (has links)
The growth of online activities in our daily lives has led to substantially increased attention on how organizations and their computer systems handle Personal Information (PI). Independently, the wide adoption of Web Service Architecture (WSA), for the integration of software, creates an opportunity to facilitate support for privacy by monitoring the use of PI by web services and enforcing applicable privacy policies. This thesis designs an agent for privacy monitoring and enforcement in a WSA environment and creates a prototype as a proof of concept. The agent is based on a specific multi-agent architecture for privacy compliance. The design of the agent has led to extension of the architecture to bring out its full potential in monitoring PI flows and enforcing privacy policies in a WSA environment. The evaluation of the prototype has led to suggestions on its implementation for an operational environment.
103

Automotive Light Assembly Failure detection

Xie, Kongying 02 October 2007 (has links)
after vibration endurance testing involves manual inspection only after the test is completed. An adaptable, reliable and low cost real time monitoring and diagnostic system that would interrupt the testing operation at the first onset of a failure is desired. This thesis describes accelerometer based, microphone (single and dualmicrophone) based and acoustic emission sensor based monitoring systems for automotive light assembly failure detection during endurance testing. Preliminary results from accelerometer based and dual-microphone based diagnostic systems show that significant differences between healthy and faulty fog light assemblies can be detected. Based on these initial testing results, subsequent testing and data analysis were conducted for accelerometer based and dual microphone based systems. Four data analysis methods have been used: (1) Averaging signals in the time domain, (2) FFT of time domain waveforms over a specified time, (3) Averaging frequency spectra, and (4) Statistical methods for time domain signals. Individual frequency spectra (from FFT) and the average of multiple frequency spectra have shown potential to distinguish between signals from faulty and healthy light assemblies. Statistical measures, such as, Arithmetic mean (μ) and Kurtosis (K) can also be used to differentiate healthy and faulty light assemblies. In general, this work has shown the good potential to develop methods for adaptable, reliable and low cost real time monitoring and diagnostic systems that would interrupt the testing operation at the first onset of a failure. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2007-09-28 16:13:47.511
104

Remote environmental sensor array system

Hall, Geoffrey G. 20 December 2007 (has links)
This thesis examines the creation of an environmental monitoring system for inhospitable environments. It has been named The Remote Environmental Sensor Array System or RESA System for short. This thesis covers the development of RESA from its inception, to the design and modeling of the hardware and software required to make it functional. Finally, the actual manufacture, and laboratory testing of the finished RESA product is discussed and documented. The RESA System is designed as a cost-effective way to bring sensors and video systems to the underwater environment. It contains as water quality probe with sensors such as dissolved oxygen, pH, temperature, specific conductivity, oxidation-reduction potential and chlorophyll a. In addition, an omni-directional hydrophone is included to detect underwater acoustic signals. It has a colour, high-definition and a low-light, black and white camera system, which it turn are coupled to a laser scaling system. Both high-intensity discharge and halogen lighting system are included to illuminate the video images. The video and laser scaling systems are manoeuvred using pan and tilt units controlled from an underwater computer box. Finally, a sediment profile imager is included to enable profile images of sediment layers to be acquired. A control and manipulation system to control the instruments and move the data across networks is integrated into the underwater system while a power distribution node provides the correct voltages to power the instruments. Laboratory testing was completed to ensure that the different instruments associated with the RESA performed as designed. This included physical testing of the motorized instruments, calibration of the instruments, benchmark performance testing and system failure exercises. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2007-12-19 10:49:51.335
105

FIELD MONITORING OF LANDSLIDE DEFORMATION USING LOW ALTITUDE PHOTOGRAMMETRY

FOSTER, JONATHAN MAXWELL 01 February 2012 (has links)
The Ottawa/Gatineau region has significant deposits of sensitive glacial marine clay. As these deposits have risen due to isostatic rebound, these materials have been incised by various watercourses, carving river valleys throughout the region. The slopes of these river banks are susceptible to retrogressive slides with significant travel distances. A novel method of monitoring changes in these landslides has been developed and is explained in this thesis. Using a tethered blimp as an aerial photo platform, high resolution digital elevations models (DEM) with accuracies of ±0.49m on vegetated slopes have been created using photogrammetry. These DEMs have been created for a several photos sets taken over time. This allows changes over time to be monitored. The use of ground control points (GCP) allows for the complete three dimensional movement of discrete points to be monitored over time. The photogrammetric DEM have been compared to similar DEM derived from LiDAR surveying. By complimenting these surveys with historical aerial photos it is possible to develop better models of landslide failure processes, which will ultimately provide better predictions of movements and failure. When movements and failures can accurately be predicted it will then be possible to better manage the risk associated with these landslides events. / Thesis (Master, Civil Engineering) -- Queen's University, 2012-01-30 16:20:27.13
106

Measurement of organic substances in the gas phase using on-line electrochemical techniques

Taylor, Malcolm G. January 1988 (has links)
Aniline was chosen as an atmospheric pollutant which might be monitored using an electrochemical sensor. The effect of pH and of different organic solvents on electrode poisoning was investigated for the analysis of aniline by voltammetry and it was concluded that it was not possible to prevent poisoning of the electrode by the reaction products. The analysis of aniline by flow injection analysis (fia) with DC (constant potential) and pulsed (double pulse) amperometric detection also suffered from electrode poisoning and the latter had a relatively high detection limit. Secondary and tertiary substituted anilines with similar volatilities to aniline at room temperature were examined as suitable alternatives to aniline using voltammetry. Dimethyl-p-toluidine poisoned the electrode to a small extent when analysed by voltammetry. Detection of this compound by fia with pulsed amperometric detection showed improved electrode stability but was not judged suitable for long term monitoring of atmospheric samples of the amine. A satisfactory method for monitoring aniline on line was developed using fia with triple pulse amperometric detection (PAD). The PAD waveform was optimised with respect to a low detection limit and a degree of selectivity towards possible atmospheric interferents for the detection of aniline in dilute aqueous acid at a platinum electrode. A wall jet cell was designed for the analysis of aniline vapour in air which was continuously trapped in dilute acid and periodically injected into a fia system. The cell was not affected by small gas bubbles and was reasonably portable.
107

Bayesian analysis of sickness absence data

Whaley, Steven R. J. January 2003 (has links)
Sickness-absence (SA) is a serious financial burden to UK industry totalling £10-12 billion in 1999 the equivalent of £434 and 7.8 days lost per worker. A major change in the reporting of SA occurred on 14 June 1982 with the introduction of self certification. Up to then all episodes had to be certified by a general practitioner. Since then, events that lasted for seven calendar or less have not required a GP's certificate and are 'self-certified'. A SA episode consists of the date the individual went off sick, the duration of the episode and a medical diagnosis given by either a GP or self diagnosis. A common approach to the analysis of SA data is to model the number of times an individual went off sick during a period of follow up via Poisson regression. Some studies on SA have examined the duration of SA, though most concentrated on the probability of going off sick. This thesis uses an intensity based approach to model the joint probability that a person goes off sick with a specific disease and has a specific duration of absence (the 'joint analysis'). A Bayesian hierarchical model, based on the conditional proportional hazards model, is formulated for the joint analysis and sampled using Markov chain Monte Carlo methods. Posterior expectations and 90% credible intervals are presented as summaries of the marginal posterior distributions of the parameters of the joint analysis. Trace plots of the log-joint posterior distribution are given to assess convergence of the MCMC sampler.
108

A Doppler ultrasound study of the umbilical artery

Dempster, J. January 1988 (has links)
Analysis of the waveforms obtained from the umbilical artery using Doppler ultrasound has been claimed in a number of recent reports to be a highly specific method of identifying babies with intrauterine growth retardation. Because of the morbidity and mortality associated with this condition it was important to evaluate the validity of those claims before introducing the method into obstetric practise. The work in this thesis was carried out in four parts. Firstly the technique was found to be reproducible with small intra and inter-observer errors. Secondly, possible influencing factors were studied, and it was found that the fetal heart rate and fetal breathing movements have a significant effect on the waveform. Thirdly, a longitudinal study of 50 healthy women with normal pregnancies was performed to define the normal range of A/B ratios (the principle method of analysis of the waveforms was the A/B ratio: ratio of peak systolic to end-diastolic frequency). Finally, Doppler ultrasound was performed in 205 women with high risk pregnancies, and results were compared to the normal reference data. When high risk cases with abnormal Doppler results (A/B ratio > 95th centile) were compared with high risk cases with normal Doppler results (A/B ratio < 95th centile) the Doppler abnormal group were found to have a significantly increased incidence of preterm delivery, operative delivery, late fetal heart rate decelerations in labour, increased admission to the special care baby unit, and increased neonatal morbidity. Although an abnormal Doppler result was associated with small for gestational age in 61% of cases, only 41% of cases of small for gestational age had abnormal Doppler results. The conclusion from this thesis is that Doppler flow velocity waveform analysis, although lacking the previously claimed diagnostic precision of detecting intrauterine growth retardation, could contribute to fetal management by identifying babies at high risk of intrapartum complications.
109

Substrate utilisation profiling of microbial communities in sewage sludge amended soils

Burgess, S. January 2002 (has links)
The aim of this thesis was to use long-term sewage sludge application to land to determine if sludge, particularly metal-rich sludge, alters the microbial community as indicated by substrate utilisation profiles (sups), using the Biolog <sup>TM</sup> method.  An additional aim was to assess Biolog<sup>TM</sup> as a rapid method of monitoring soil health. Sludge rich in Cadmium altered microbial community profiles, but this was possibly due to differences in organic Carbon quality between sludges used in the trial.  Conditioning (incubation) of soils before analysis with Biolog<sup>TM</sup> made these effects more apparent.  Storage of soil also altered microbial activity and community profiles, which were not restored by a conditioning period.  Both incubation and storage influenced the Biolog<sup>TM</sup> response and can potentially affect available soil C. Therefore, the effects of organic matter application at high levels on the microbial community, were assessed without metals.  Low metals sludge altered microbial community function, although the trends were not consistent across soil types.  Biolog<sup>TM</sup> was more sensitive to sludge treatment effects than total microbial biomass C. The microbial community responses to sludge and preparation disturbance were examined (using Biolog<sup>TM</sup> and microbial PLFAs). A method to determine extractable carbohydrates was adapted for use in a microplate format, and was employed to assess the relationship between microbial community change and available soil C.  Changes in soil microbial community structure and function were not related to extractable carbohydrate C.  Biolog<sup>TM</sup> and PLFA responded differently:  disturbance had a greater effect on Biolog response than either application of sewage sludge or the quality of soil C;  but PLFAs were more affected by long-term sewage sludge amendment, highlighting implications for the monitoring of waste-amended soils.
110

Energy management in diverse estates

Evans, Mark S. January 2001 (has links)
No description available.

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