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Reconsolidation theory states that stabilized memories can be reactivated and altered in some way; the memory must then be made stable once again by a process known as reconsolidation. A substantial number of studies have aimed to examine this process and the conditions under which it can occur in animal models and young adults. However, few studies have examined the impact of aging on memory reconsolidation. It has been established that aging affects episodic memories, as a result of several different changes in aging. Further, associative, source, and context memories have been found to be affected by aging. Additionally, consolidation, the process that occurs prior to reconsolidation, has been linked to age-related memory deficits. Given these changes with age, it is possible that memory reconsolidation could also be affected. This dissertation sought to examine the effects of aging on reconsolidation in an established set-learning paradigm typically utilized in young adults to demonstrate reconsolidation-mediated memory updating. In Experiment 1, older adult participants were taught sets of objects on two different days, with one group receiving a reminder intended to reactivate the first day's memory. On a third day, a recognition memory task was given. We found that reconsolidation processes seem relatively intact in our population of older adults. Further, source confusion was implicated in addition to memory updating as the cause of memory errors in the group that received the reminder. Other measures, such as spatial awareness and sleep, were utilized to help explain the outcome of the experiment. In Experiment 2, young adults performed the same procedure as in Experiment 1 to determine the role of some of the aspects of the procedure in this paradigm. Specifically, we wanted to establish whether an added task, spread across the two days of learning, influenced the outcome of this paradigm. It was concluded that this task likely had an influence, such that even the group that did not receive the reminder showed evidence of memory updating. We also wanted to determine a baseline for the spatial awareness task used in the previous experiment. However, results were inconclusive. In Experiment 3, we investigated the time line of errors made by older adults by testing their memory for the first set of objects shortly after they learned the second set, as opposed to on a third day. However, free recall was used as the memory task, unlike the previous two experiments. Unexpectedly, errors were immediately apparent for the group that did not receive the reminder but not for the group that did. The conclusion of this experiment was that the task used to test memory may play a major role in the outcome of this paradigm when performed by older adults. Further testing will need to be performed to fully understand this result. Overall, memory reconsolidation appears to be intact in older adults, though perhaps not in the form seen in young adults. Reconsolidation seen in older adults could be affected by different modes of reactivation, sleep, and methods of memory testing. However, several of the present results could be open to multiple interpretations, which require future research to untangle.

When spatial updating tasks are performed in a real-world setting, participants usually complete it with ease (e.g., Klatzky et al., 1998). However, in virtual reality (VR), when tasks are presented using optic flow, participants tend to exhibit one of two response patterns, with some participants correctly updating their headings (“turners”) and others pointing consistently in the opposite direction (“non-turners”) (e.g., Gramann et al., 2005). While research has looked at the stability and pointing characteristics of these two groups (e.g., Gramann et al., 2012; Riecke, 2008), we still do not know why non-turners exist. The following thesis studied two potential sources of cue conflict—stationary versus central visual information and sensorimotor interference—that could impact participants’ strategies using the Starfield task (Gramann et al., 2012). Occluding stationary peripheral information increased pointing errors, especially for turners. It is thus possible that turners require the peripheral information to correctly parse and process the central optic flow. Alternatively, manipulating body orientation to decrease sensorimotor interference seemed to decrease error and increase strategy consistency for both turners and non-turners. It is possible that the orientation changes allowed participants to ignore the stationary body- based cues, thereby improving spatial updating. Although these manipulations did not remove the non-turner group altogether, they provided important insights into how cue conflicts may play a role in spatial updating for VR tasks. / Thesis / Master of Science (MSc)

During everyday scene viewing, the information received by the visual system is frequently disrupted: Objects are often occluded by other objects, and sensory processing is interrupted by eye, head, or body movements. The visual system is extremely efficient at correcting for these interruptions and in establishing object correspondence and perceptual continuity. At the end of this correspondence process, the visual system is left with two representations of an object: The initial representation and the one acquired after the disruption. In the present dissertation, I investigated the mechanisms by which the visual system reconciles these discontinuous inputs to give us a perception of a smooth and stable visual world. To achieve this, I ran four experiments in which participants were presented with a colored saccade target, and instructed to remember its color before executing the saccade. On some trials, the color of the saccade target was changed to a new value during the saccade. Participants were asked to report either the pre- or post-saccadic color value in a continuous report task. Object continuity was manipulated in two ways. The target blanking paradigm served as the main manipulation of stability: On half the trials, the target was removed from the screen during the saccade, disrupting object continuity. In addition, the magnitude of color change was used as a secondary manipulation of visual stability. The color report data were fit with probabilistic mixture models. First, there was no evidence for integration of pre- and post-saccadic feature values into a composite representation. Instead, on a majority of trials participants could successfully retain and report both pre- and post-saccadic states of the target object. Further, these two states dynamically interacted with each other, resulting in their feature values systematically shifting toward each other. Lastly, when reporting the pre-saccadic color, participants were more likely to incorrectly report the post-saccadic color under conditions of visual stability versus instability, supporting a probabilistic overwriting mechanism. Together, these results are more consistent with an object-based model, rather than an image-based model of representational updating. Although the present study only focused on transsaccadic updating mechanisms, similar mechanisms are likely to be functional in many common situations where the visual system needs to establish perceptual continuity across disruptions and changes.

Finite-element model updating is the process of using measured data from a structure to update a numerical model representation of the structure. The measured data can represent either the static or dynamic properties of the structure. This document reviews and evaluates several methods of finite-element (FE) model updating, including direct, indirect, and control-based methods for the dynamic case. It is important to have a correct finite-element model obtained using model updating methods either to assess the current condition, or to modify the structure from its current state. In this study, three types of methods were evaluated; direct, indirect, and control based finite-element model updating methods. Each method was first used to update a simple example model for two separate cases. For the first case, the entire set of measured modal parameters were used; and for the second case, only a sub-set of the eigenvalues were used. These examples provide insights into the advantages and disadvantages of various methods. The model updating methods are also used to update a full-scale 42 degree of freedom model. Since it is not practical to measure all the degrees of freedom, the model was reduced using the SEREP model reduction method, down to 18 degrees of freedom. This was done to evaluate the effectiveness of the model updating methods on a real structure. Detailed methodologies and a comparison between the relative advantages and disadvantages between various model updating methods are highlighted in this thesis.

Finite-element model updating is the process of using measured data from a structure to update a numerical model representation of the structure. The measured data can represent either the static or dynamic properties of the structure. This document reviews and evaluates several methods of finite-element (FE) model updating, including direct, indirect, and control-based methods for the dynamic case. It is important to have a correct finite-element model obtained using model updating methods either to assess the current condition, or to modify the structure from its current state. In this study, three types of methods were evaluated; direct, indirect, and control based finite-element model updating methods. Each method was first used to update a simple example model for two separate cases. For the first case, the entire set of measured modal parameters were used; and for the second case, only a sub-set of the eigenvalues were used. These examples provide insights into the advantages and disadvantages of various methods. The model updating methods are also used to update a full-scale 42 degree of freedom model. Since it is not practical to measure all the degrees of freedom, the model was reduced using the SEREP model reduction method, down to 18 degrees of freedom. This was done to evaluate the effectiveness of the model updating methods on a real structure. Detailed methodologies and a comparison between the relative advantages and disadvantages between various model updating methods are highlighted in this thesis.

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In a Bayesian perspective, the probabilistic dependencies between hypotheses under consideration and diagnostic pieces of evidence are the only relevant information for probabilistic updating. We investigated whether human probability judgments conform to this assumption, by manipulating the sensory systems involved in the acquisition and processing of information concerning evidence and hypotheses. Hence, we ran five (computer-based) experiments using a variant of the classic book bag and poker chip task (e.g., Phillips & Edwards, 1966). Participants were first presented with pairs of urns A and B filled with a different proportion of balls that turned either red or green in the visual condition, balls that emitted either a low- or high-pitched sound in the auditory condition, and balls that both turned a color and emitted a sound in various cross-modal (i.e., audio-visual) conditions. One urn was then selected at random, some balls were randomly drawn from it, and their color and/or sound were disclosed. Participants’ task was to estimate the probability that each of the two urns has been selected, given the information provided. In Experiments 1 and 2, we compared the probability judgments referring to probabilistically identical visual and auditory scenarios that only differed with regards to the sensory system involved, without finding any difference between the answers provided in the two conditions. In Experiment 3, 4, and 5, the addition of cross-modal scenarios allowed us to investigate the effects on probabilistic updating of synergic (i.e., both visual and auditory evidence individually supported the hypothesis they jointly supported) or contrasting (i.e., either visual and/or auditory evidence individually supported the hypothesis opposite the one they jointly supported) audio-visual evidence. Our results provide evidence in favor of a synergy-contrasting effect, as probability judgments were more accurate in synergic conditions than in contrasting conditions. This suggests that, when perceptual information is acquired through a singular sensory system, probability judgments conform to the Bayesian assumption that the sensory system involved does not play a role in the updating process, whereas the simultaneous presentation of cross-modal information can influence participants’ performance.

Sustainable Built Environments Senior Capstone Project / Abstract Suburbs have long been a place near and dear to the hearts of many, they provide private property, large homes and a sense of security. They have traditionally been located far from city centers and also far from jobs. The following paper researchers whether or not suburban homes can be updated to compensate for the extra distance their inhabitants have to commute to work. The study looks at three case houses in the focus area of Continental Ranch, a Pulte suburb. The follow research was performed using a cost benefit analysis on three case homes and four case vehicles. The results were calculated using available data, estimates and website based calculators. The five upgrades calculated were CFL/LED light bulb replacement, water fixture upgrades, fridge replacement, rainwater harvesting and installation of solar panels. The case homes varied in size from 1,369 to 3,609 square feet and were built between 1989 and 2001. The homes have between two to five bedrooms and two to three bathrooms. The cars chosen as vehicle options for comparison were the Toyota Prius, the Honda Civic, the Honda Odyssey and the Chevrolet Tahoe, all 2016 models. The results found that all three homes could be upgraded to compensate for the annual cost of gas consumption of all four car options. It should be noted that these calculations did not take into account the cost of the upgrades, but rather the savings it would procure.

In the global framework of improving vibro-acoustic numerical prediction quality together with the need to decrease the number of prototyping stages, this manuscript focuses on achieving greater accuracy for acoustic numerical simulations by making use of a parametric updating technique, which enables tuning the model parameters inside physically meaningful boundaries. The improved model is used for the next prototyping stages, allowing more accurate results within reduced simulation times. The updating technique is based on recent works dealing with the constitutive relation error method (CRE) applied to acoustics. The updating process focuses on improving the acoustic damping matrix related to the absorbing properties of the materials covering the borders of the acoustic domain.