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Objective quality evaluation is a key element for the success of the emerging Voice over IP (VoIP) technologies. Although there are extensive economic incentives for the convergence of voice, data, and video networks, packet networks such as the Internet have inherent incompatibilities with the transport of real time services. Under this paradigm, network planners and administrators are interested in ongoing mechanisms to measure and ensure the quality of these real time services. Objective quality assessment algorithms can be broadly divided into a) intrusive (methods that require a reference signal), and b) non intrusive (methods that do not require a known reference signal). The latter group, typically requires knowledge of the network conditions (level of delay, jitter, packet loss, etc.), and that has been a very active area of research in the past decade. The state of the art methods for objective non-intrusive quality assessment provide high correlations with the subjective tests. Although good correlations have been achieved already for objective non-intrusive quality assessment, the current large voice transport networks are in a hybrid state, where the necessary network parameters cannot easily be observed from the packet traffic between nodes. This thesis proposes a new process, the Network Conditions Estimator (NCE), which can serve as bridge element to real-world hybrid networks. Two classifications systems, an artificial neural network and a C4.5 decision tree, were developed using speech from a database collected from experiments under controlled network conditions. The database was composed of a group of four female speakers and three male speakers, who conducted unscripted conversations without knowledge about the details of the experiment. Using mel frequency cepstral coefficients (MFCCs) as the feature-set, an accuracy of about 70% was achieved in detecting the presence of jitter or packet loss on the channel. This resulting classifier can be incorporated as an input to the E-Model, in order to properly estimate the QoS of a network in real time. Additionally, rather than just providing an estimation of subjective quality of service provided, the NCE provides an insight into the cause for low performance.

Intrusive cognitions are a natural occurrence within our stream of consciousness, however, when they become repetitive, negative, distressing, and difficult to control, they may warrant clinical concern. Thought suppression is a common control strategy used to manage intrusive thoughts even though research suggests it may actually exacerbate the problem. Conversely, acceptance-based interventions have gained recent attention as an alternative strategy for managing distressing internal experiences. Only preliminary research has focused on the psycho- and neurophysiological bases of intrusive cognitions, and their relationship to cognitive control strategies. Evidence suggests that the anterior cingulate cortex (ACC) may be a brain region critically involved in this process. The present investigation compared the subjective, behavioral, and physiological effects of a thought suppression and acceptance strategy in a sample of university students with high or low obsessive-compulsive (OC) characteristics who were exposed to an emotion-evoking film clip. Participants were instructed either to suppress or accept any intrusive cognitions during a rest period after the film clip, while monitoring for the number of intrusions. Next, psychophysiological signals and reaction times were measured while participants performed a variant of the Stroop task. The commission of errors during a forced choice task generates an error-related negativity (ERN), which is believed to index activity in the ACC. Results showed that self-reported intrusions during the rest interval were greater for the acceptance group and the high-OC group. Correlations suggested that participants who reported more effort at suppression also indicated more distress about their thoughts, whereas those who reported more acceptance indicated less distress. During Stroop task errors, the ERN was apparent as a maximal frontal negativity, and was larger for the suppression group than the acceptance group at a frontal scalp site (Fz), but not a central scalp site (Cz). Correlations between self-reported intrusions at rest and ERN amplitude indicated that participants who reported fewer intrusions demonstrated enhanced ERNs, a marker for increased ACC activity. These findings may be interpreted as supporting the hypothesis that thought suppression is associated with increased ACC activity and greater self-reported discomfort with the intrusions.

Intrusive memories, coping strategies, negative appraisals, and perceptions of control were examined in an unselected undergraduate sample. Intrusive memory frequency was positively associated with emotion-avoidant coping, but unrelated to problem-focused and emotion-approach coping. Negative appraisals and perceptions of control partially mediated the relationship between intrusive memory frequency and emotion-avoidant coping. PTSD symptoms contributed additional variance to the partial mediation models. Overall, study findings demonstrated that the intrusive memory maintenance cycle found in PTSD and depression samples can exist in an unselected sample. Individual differences within this sample may relate to varying levels of executive control and trait mindfulness. Implications for clinical practice, limitations, and directions for future research are discussed.

Cognitive-behavioral therapy that includes exposure, or intentionally and systematically confronting feared situations, is the gold standard psychological treatment for obsessive-compulsive disorder. However, less than half of those who begin this treatment are considered to have recovered from their disorder at the end of treatment, and this number is even smaller in the months following the end of treatment. Leading theories regarding how treatment changes occur focus on reducing fear, and they do not include “voluntary” (i.e., operant) behaviors, such as avoidance, that are key features of the disorder. Acceptance-based approaches to exposure do not focus on fear reduction, but directly focus on changing “voluntary” behaviors. Combining these two perspectives could lead to a better understanding of how exposure works and, ultimately, lead to more effective and long-lasting psychological treatments for obsessive-compulsive disorder. The current study investigated whether accepting distress or attempting to reduce distress during exposure for intrusive thoughts led to different outcomes and whether they led to these outcomes in different ways. Participants with intrusive thoughts were randomized to three groups, Acceptance (n = 23), Regulation (n = 20), and Control (n = 21), and completed two sessions 1week apart. Participants in the Acceptance and Regulation groups completed a 30-minute exposure at session 1 and 6 days of 10-minute exposures at home; Control participants watched videos of the same lengths. Self-report questionnaires, measures of behavior, self-ratings, and physiological data were collected at both sessions. Results showed that Acceptance and Regulation groups decreased on measures of obsessive-compulsive symptom severity, rituals performed, self-rated distress, and skin conductance levels. Acceptance showed lower skin conductance and a statistical trend toward greater self-rated willingness to experience distress than Regulation, as well as greater psychological flexibility than Control. There were no between group differences in the number of exposure tasks completed during a behavioral test, psychological inflexibility, valued living, or heart rate. This study suggests that psychological flexibility and willingness to experience distress may paradoxically lead to decreased physiological arousal, findings which may inform future research and treatment approaches.

Thought-action fusion (TAF) is the phenomenon whereby one has difficulty separating cognitions, particularly those that are intrusive and disturbing, from their corresponding behaviors. Recent work has suggested that TAF is malleable and amenable to change. The current study examined the effects of three different psychoeducational interventions on thought-action fusion, anxiety, thought suppression, magical thinking, and responsibility cognitions. Assessments were conducted both immediately following the interventions and after a two-week period. Results indicated that individuals who received a cognitive-based intervention that targeted irrational thoughts had significantly lower TAF scores than individuals who received an intervention that discussed thoughts from a non-evaluative framework and individuals in the control group, both immediately following the intervention and at the two-week follow-up. As hypothesized, all groups experienced a significant decrease in anxiety between the post-intervention and follow-up assessments; however, there was a trend towards significance for those who were exposed to the cognitive-based intervention to experience a greater decrease in anxiety than those in the control group. The cognitive-based intervention group was the only group that did not experience a significant increase in thought-suppression from baseline to post-intervention, and was also the only group to experience an increase in both frequency of and belief in low-responsibility thoughts from baseline to follow-up. No significant group differences were found for the construct of magical thinking. Implications are discussed.

Obsessive Compulsive Disorder (OCD) has been linked to a dysmorphic construction of self that is closely tied to mental illness (Bhar & Kyrios, 2007). Although associations have been found, no study has determined the impact of OCD on one's self-perception, to better understand how to resolve patients' dysmorphic construction and fear of oneself. College students (N = 410; M = 20.60, SD = 4.27) completed an anonymous online survey for course credit. The survey consisted of a demographic questionnaire, the Obsessive-Compulsive Inventory-Revised (Foa et al., 2002), theEgo-Dystonicity Questionnaire (Purdon et al., 2007), and the Self-concept Identity Measure (Kaufman et al., 2019). To determine if scores on the Obsessive-Compulsive Inventory would predict scores on the Identity Measure and if the Ego-Dystonicity scale would account for a greater percentage of the variation in Identity subscale scores than Obsessing scores alone, multiple regression analyses were utilized. Results suggest that although, symptoms of OCD were useful in predicting variance all of the identity subscales, ego-dystonicity appeared to be particularly useful for establishing incremental validity in the prediction of the lack of identity subscale. Implications for intervention and prevention efforts in regard to the effects of OCD on identity will be discussed.

La métrologie non-intrusive est une composante essentielle de la recherche expérimentale en mécanique des fluides. La connaissance instantanée des champs de vitesse et de température apportent des informations essentielles à la compréhension des phénomènes instationnaires aérothermiques. Toutefois, si les mesures de vitesses sont aisément réalisées, l’obtention de champs de température s’avère plus complexe. L’une des voies étudiées pour y parvenir estla Fluorescence Plane Induite par LASER, ou PLIF. Son principe repose sur l’acquisition de signaux lumineux de fluorescence, dépendants de la température, consécutifs à l’excitation du milieu par un faisceau LASER intense. En particulier, la PLIF acétone à deux longueurs d’onde emploie l’acétone comme traceur fluorescent et deux LASER comme source d’excitation pour s’affranchir de la dépendance en concentration en acétone. Toutefois, selon la longueur d’onde,l’énergie LASER ou la gamme de température explorée, la PLIF-2λ peut s’avérer difficile à mettre en oeuvre du fait d’un manque de sensibilité, lié à un signal de fluorescence trop faible.Dès lors, plusieurs étapes correctives visant à améliorer le rapport signal-sur-bruit peuvent être mises en oeuvre. Le présent travail s’intéresse ainsi à déterminer la pertinence de cette méthode métrologique dans la qualification aérothermique d’un écoulement de convection mixte autour d’un cylindre chauffé, en couplant la PLIF-2λ à la Vélocimétrie par Imagerie de Particules(PIV). Le montage expérimental est détaillé, ainsi que les processus correctifs et l’étalonnage mis en place pour la PLIF. Les résultats expérimentaux sur le cylindre chauffé sont ensuite présentés et comparés aux travaux de la littérature, puis un modèle de la fluorescence et des caméras employées est élaboré pour permettre d’estimer la précision atteignable en pratique selon la longueur d’onde, l’énergie LASER, la concentration et les caméras, et ainsi rendre possible la présélection des équipements nécessaires aux travaux futurs. / Non-intrusive metrology is essential in experimental fluid mechanics experiments. In particular, simultaneous acquisition of instantaneous velocity and temperature fields offers valuable insights in instationnary aerothermal behaviours. However, if instantaneous velocity fields can be acquired quite easily using the Particles Image Velocimetry technic (PIV), instantaneous temperature fields are much more complex to obtain. Plannar Laser Induced Fluorescence (PLIF) is one of the technics allowing such a measurement. The emitted LASER light induces excitation of acetone molecules, the tracer in the studied air flow. Then, the fluorescence following de-excitation, which is temperature-dependant, is recorded. In particular, 2 λ-PLIF uses dual wavelength LASER excitation to remove acetone concentration dependency in the measurement. Yet, depending of the wavelengths, the LASER energy or the temperature range investigated, using 2 λ-PLIF can be difficult due to a very low temperature sensitivity and very dim fluorescence. To solve those issues and improve signal-to-noise ratio, acquired images can be corrected according to different parameters in an interative process. Present work is dedicated to evaluate efficiency of corrected 2 λ-PLIF applied to the study of a mixed convection flow around a heated cylinder in the 20-300 C temperature range. The goal is to obtain aerothermal qualification of the flow thanks to simultaneous 2 λ-PLIF and PIV. In the present work, experimental bench is detailled as well as the calibrating and correcting process of the 2 λ-PLIF. Then, experimental results are discussed and confronted to results from litterature. Finally, a model of the fluorescence and camera-generated noise is discussed and used to generate simulated fluroescence images and determine the impact of all parameters (wavelengths, LASER energy, acetone concentration and camera intensification gain) on the measurement precision and thus enable adequate choice of equipments for next experiments.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / Adding an instrumentation / telemetry system to a test vehicle has historically required an intrusive installation for wiring and powering all elements of the system from the sensor to the telemetry transmitter. In some applications there is need for a flexible and modular instrumentation and telemetry system that can be installed with minimal intrusiveness on an aircraft without the need for permanent modifications. Such an application may benefit from the use of a miniaturized, inexpensive network of wireless sensors. This network will communicate its data to a central unit installed within the aircraft. This paper describes recent efforts associated with the Advanced Subminiature Telemetry System (ASMT) Initial Test Capability Project. It discusses the challenges in developing a wireless sensor network system for use in an airborne environment. These include selection of frequencies, COTS wireless devices, batteries, system synchronization, data bandwidth calculations, and mechanical structure for external installation. The paper will also describe the wireless network architecture as well as the architecture of the wireless sensor and the central control unit.