In this paper we consider optimum design of experiments for correlated observations. We approximate the error component of the process by an eigenvector expansion of the corresponding covariance function. Furthermore we study the limit behavior of an additional white noise as a regularization tool. The approach is illustrated by some typical examples. (authors' abstract) / Series: Research Report Series / Department of Statistics and Mathematics

We present a controlled experiment for the empirical evaluation of Example-Driven Modeling (EDM), an approach that systematically uses examples for model comprehension and domain knowledge transfer. We conducted the experiment with 26 graduate and undergraduate students from electrical and computer engineering (ECE), computer science (CS), and software engineering (SE) programs at the University of Waterloo. The experiment involves a domain model, with a UML class diagram representing the domain abstractions and UML object diagrams representing examples of using these abstractions. The goal is to provide empirical evidence of the effects of suitable examples on model comprehension, compared to having model abstractions only, by having the participants perform model comprehension tasks. Our results show that EDM is superior to having model abstractions only, with an improvement of (+39%) for diagram completeness, (+30%) for study questions completeness, (+71%) for efficiency, and a reduction of (-80%) for the number of mistakes. We provide qualitative results showing that participants receiving model abstractions augmented with examples experienced lower perceived difficulty in performing the comprehension tasks, higher perceived confidence in their tasks' solutions, and asked fewer clarifying domain questions (a reduction of 90%). We also present participants' feedback regarding the usefulness of the provided examples, the number of examples, the types of examples, and the use of partial examples.

Many services fail. Failures are those encounters during which the user assesses the service as flawed (Maxham & Netemeyer, 2003; Palmer, Beggs, & Keown-McMullan, 2000), or improper (Maxham, 2001). An emergent service failure literature has determined that such failures play an important role in user perceptions and subsequent behaviours. The present study sought to discover the ways in which possible users responded to an ambiguous service failure. The purpose of the study was to twofold: (a) to understand the situational, emotional, and dispositional factors which influence users??? likelihood of complaining behaviours; (b) to develop connections between these factors and users??? preferences for service recovery. We were guided by several research questions including: RQ1: When the cause of the failure is ambiguous, to what/whom do users attribute blame? RQ2: How well do attribution of blame and perceived failure severity predict negative emotions? RQ3: What is the relative influence of each negative emotion in predicting the likelihood of each complaining behavior? RQ4: Does user disposition intervene in the relationship between emotion and complaining? RQ5: What is the role of appraisals and emotion in determining service recovery preferences? Borrowing from the service quality, consumer behaviour, health, and therapy literatures, we develop a conceptual framework for answering our questions. Consistent with recent research, we conceptualized that negative emotions following service failures were dependent on users??? appraisals of the situation. Specifically, we looked at the effects of failure severity and attribution of blame on anger, frustration, shame, guilt, regret, and dissatisfaction. We then conceptualized complaining behaviour as a coping mechanism for these negative emotions, and preferences for service recovery as manifestations of immediate desires users would have to address their emotions. To test our theory, an experiment with hypothetical scenarios and a survey instrument was developed. We manipulated two conditions (time lost and money lost) at different points in the survey while participants while self-selected into an attribution of blame condition (Self, provider, other). Undergraduate students at the University of Waterloo (n=288) served as the sample. The questionnaire assessed such variables as attitudes towards complaining, locus of control, tendency for avoidance, emotional response, complaining behaviours, and preferences for service recovery. Results from multivariate analyses confirmed that appraisals help predict negative emotions, and that negative emotions influence complaining behaviours. Results also demonstrated that appraisals and emotions do begin to explain variance in service recovery preferences. Contrary to the interactionist approach, results failed to support the notion that personal dispositions (such as attitudes and personality traits) moderate the relationship between situational factors and behaviour. Finally, conclusions for the study are made, and implications for future research and the design of service recovery strategies are discussed.

Uppsatsen är dels en skriftlig dokumentation av en konstnärlig process i sökande av design genom begreppen fast och följsamt samt gestaltandet, dokumenterat genom fotografi, av ett experimenterande av kontrasterande material.

To manage underused urban grassy spaces like transmission lines as tall-grass prairie habitats or other endangered ecosystems, ecologists need to know how mowing, spraying and surrounding urban lands affect species richness and numbers of plants and animals along transmission lines. I conducted surveys along 48 transmission lines in Winnipeg, Manitoba in 2007-2009 to answer these questions, and I concluded that mowing and spraying should be reduced, but not eliminated, to increase butterflies and other arthropods, resources for butterflies and other arthropods, and arthropod prey for birds. However, the amount of nearby urban land reduced plant species richness and grassland bird abundance along lines more strongly than mowing or spraying, suggesting that lines with less nearby urban land should be selected for management as grassland bird habitats. Mowing and spraying can then be reduced along these lines to benefit other species, enabling urban lands like transmission lines to contribute to conservation.

Passive dynamic walking is a manner of walking developed, partially or in whole, by the energy provided by gravity. Studying passive dynamic walking provides insight into human walking and is an invaluable tool for designing energy efficient biped robots. The objective of this research was to develop a new mathematical model of passive dynamic walking that modeled the ground reaction forces. A physical passive walker was built to validate the proposed mathematical model. The stability of the gait was analyzed using the proposed model. A novel method was created to determine the stability region of the model. Using the insights gained from the stability analysis, the relation between the angular momentum and the stability of the gait was examined. The proposed model matched the gait of the physical passive walker exceptionally well, both in trend and magnitude. The angular momentum of the passive walker was not found to correlate to the stability of the gait.

We consider observations of a random field (or a random process), which is modeled by a nonlinear regression with a parametrized mean (or trend) and a parametrized covariance function. In the first part we show that under the assumption that the errors are normal with small variances, even when the number of observations is small, the ML estimators of both parameters are approximately unbiased, uncorrelated, with variances given by the inverse of the Fisher information matrix. In the second part we are extending the result of Pazman & Müller (2001) to the case of parametrized covariance function, namely we prove that the optimum designs with and without the presence of the virtual noise are identical. This in principle justify the use the method of virtual noise as a computational device also in this case. (authors' abstract) / Series: Research Report Series / Department of Statistics and Mathematics

In fractured geologic media, flow and contaminant transport are predominantly controlled by the fractures, their distribution and connectivity. The accurate characterization of fractured geologic medium, imaging of fracture patterns and their connectivity have been a challenge for decades. Given the complexities of fractured networks in the subsurface and Dense Non Aqueous Phase Liquid (DNAPL) contamination, in this thesis, transient hydraulic tomography (THT), a recently developed tool for characterizing aquifer heterogeneity is evaluated under laboratory conditions to delineate discrete fractures. Laboratory experiments and modeling studies are also conducted to understand TCE plume behavior. A dolomite rock sample, which is 91.5 cm in length, 60.5 cm in height and 5 cm thick, was fractured in the laboratory to perform the experiments. After the fractured block was enclosed in a flow cell, flow-through and pumping tests were conducted to characterize the fractured rock block. The data from the pumping tests were then analyzed using the SSLE code developed by Zhu and Yeh [2005] and transient hydraulic tomography (THT) was conducted to image the fracture pattern and their connectivity through the delineation of K and Ss distributions (the tomograms). Synthetic pumping tests, identical in configuration to the laboratory ones were also conducted using HydroGeoSphere (HGS) [Therrien et al, 2009] in a synthetic replica of the fractured block to compare the observed and simulated drawdowns. Then synthetic THT analysis was performed utilizing the synthetic pumping test data to compare the tomograms obtained from the THT analysis of synthetic and laboratory pumping tests. Results suggest that the THT analysis of multiple laboratory pumping tests captured the fracture pattern and their connectivity quite well and they became more vivid with the additional pumping tests. The estimated high hydraulic conductivity (K) and low specific storage (Ss) zones clearly show the fractures and their connectivity. The pattern of K and Ss tomograms obtained from the analyses of synthetic and laboratory pumping tests were similar. Estimated K and Ss values for the fractures and the matrix may not exactly replicate the actual K and Ss values for the fractured rock, but the model also provides uncertainty estimates associated with the resulting K and Ss tomograms. In this study, two cases of transient hydraulic tomography (THT) analysis of the laboratory pumping tests were performed by changing the location of 2nd and 3rd pumping tests among the three to examine if there is any significant impact of these pumped location on the pattern of resulting hydraulic conductivity (K) and specific storage (Ss). The initial pumping test was the same for two cases. Results show that the patterns of estimated K and Ss tomograms obtained from these two cases are similar, although the pumped locations (2nd and 3rd tests among the three) utilized for the inversion were different for two cases suggesting that the location of these later pumping tests does not significantly impact the estimates for this fractured rock block. However, the initial test should be selected carefully as that seems to set the pattern of the tomograms. The estimated K and Ss tomograms were validated by predicting five independent pumping tests conducted in the fractured rock block. These five pumping tests were not included during the construction of the K and Ss tomograms. For most of the independent pumping tests, good correspondence between the simulated and observed drawdown was achieved. The study indicates that, it is possible to delineate discrete fractures, their pattern and connectivity by carefully applying of THT analysis of multiple pumping tests based on the inverse code SSLE [Zhu and Yeh, 2005]. In addition, hydraulic tomography seems to be a cost effective tool for characterizing fractured rock since it does not require the detailed information on fracture geometry parameters such as aperture, trace length, orientation, spatial distribution, and connectivity, which are difficult to quantify. These parameters are usually unavailable between boreholes. Therefore, THT appears to be a promising approach in delineating fractures and their connectivity in subsurface. However, it is still at the early stage as the study was conducted in the laboratory under controlled conditions. Small scale field experiments need to be conducted to validate THT as a tool for the characterization of hydraulic parameters of fractured rocks. Upon completion of the hydraulic characterization, several conservative tracer tests were conducted using bromide (Br-) as a conservative tracer to aid in the design of TCE dissolution experiment. Once the tracer experiments were completed, a known volume of pure phase TCE was injected at a known location in the flow cell to create a well-defined source zone. A constant hydraulic gradient was maintained by fixing the hydraulic heads at the two head tanks to induce steady groundwater flow through the flow cell. Water samples were obtained at a down gradient monitoring port for 3 months to obtain a long-term breakthrough curve of TCE in the aqueous phase. The purpose of this experiment was to study TCE dissolution behaviour in the fractured rock sample. Then HydroGeoSphere (HGS) was used to model the aqueous phase TCE transport using two separate approaches: 1) the Discrete Fracture Network modeling approach and 2) the stochastic continuum approach, to investigate whether they can capture the dissolution behavior. Both approaches were able to capture the pattern of the breakthrough curve in the fractured rock. The discrete fracture approach captured the observed TCE plume and the dissolution behavior quite well. On the other hand, the stochastic continuum approach, in which the fractured rock block was treated as porous medium having a heterogeneous K field obtained from THT analysis, also appeared to be promising in capturing the aqueous phase transport of TCE. Despite some early time deviation, the simulated breakthrough curve captured the overall observed concentration profile. However, the stochastic continuum approach seems to be more cost effective as it does not require detailed information about fracture aperture and their spatial distribution which are difficult if not impossible to obtain between boreholes. Note that, the studies were conducted based on a laboratory experiment conducted in a controlled environment. The experimental block was well characterized and the geometry of the experimental block as well as the flow through the system was well understood from the hydraulic and tracer experiments. Thus small scale field experiment is required to support this conclusion.

Zugl.: Duisburg, Essen, Univ., Diss., 2006

Zugl.: Hildesheim, University, Diss., 2006.