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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.
11

Numerical Methods for Long-Term Impulse Control Problems in Finance

Belanger, Amelie January 2008 (has links)
Several of the more complex optimization problems in finance can be characterized as impulse control problems. Impulse control problems can be written as quasi-variational inequalities, which are then solved to determine the optimal control strategy. Since most quasi-variational inequalities do not have analytical solutions, numerical methods are generally used in the solution process. In this thesis, the impulse control problem framework is applied to value two complex long-term option-type contracts. Both pricing problems considered are cast as impulse control problems and solved using an implicit approach based on either the penalty method or the operator splitting scheme. The first contract chosen is an exotic employee stock option referred to as an infinite reload option. This contract provides the owner with an infinite number of reload opportunities. Each time a reload occurs, the owner pays the strike price using pre-owned company shares and, in return, receives one share for each option exercised and a portion of a new reload option. Numerical methods based on the classic Black-Scholes equation are developed while taking into account contract features such as vesting periods. In addition, the value of an infinite reload option to it's owner is obtained by using a utility maximization approach. The second long-term contract considered is a variable annuity with a guaranteed minimum death benefit (GMDB) clause. Numerical methods are developed to determine the cost of the GMDB clause while including features such as partial withdrawals. The pricing model is then used to determine the fair insurance charge which minimizes the cost of the contract to the issuer. Due to the long maturity of variable annuities, non-constant market parameters expressed through the use of regime-switching are included in the GMDB pricing model.
12

Laminated Gas Generator Actuator Arrays

English, Brian Alan 20 November 2006 (has links)
Existing microactuator limitations prevent control of small-scale, spin-stabilized vehicles. These applications require actuators insensitive to shock that have forces on the order of Newtons and millisecond control periods. This research presents batch-fabrication lamination approaches for the realization of large arrays of high-impulse, short-duration gas generator actuators (GGAs), and system implementation approaches to integrate these GGAs into a small-scale, spin-stabilized projectile for the purpose of generating steering forces on the projectile. Electronic packaging and MEMS processing are combined to batch-fabricate millimeter-scale GGAs insensitive to large shocks. Robust, prefabricated thermoplastic and metal films are patterned by laser machining or photolithography, and multilayer devices are assembled by adhesive lamination. The GGAs remained operational after 10,000 g shocks. Optimized design and propellant selection enables control of the force profile and actuation timing. Rapid force rise times are achieved using appropriately selected solid propellants and specially designed hot-wire igniters that create a larger combustion fronts. By reshaping the combustion profile of the solid propellant, tens of Newtons are generated within milliseconds. In addition to force control, the timing of the force application was controllable to within 1 ms for optimized GGAs. Performance results demonstrate that GGA actuator arrays actuate within appropriate timescales and with enough authority to control a 40 mm projectile with a spin rate of 60 Hz. After actuator characterization, GGAs, control electronics, and power supply are mounted into a 40 mm diameter projectile, and a full flight system was flown to demonstrate divert authority of the GGAs.
13

Elucidating the relation of hoarding to obsessive compulsive disorder and impulse control disorders

Cook, Laura Michele. January 2007 (has links)
Thesis (M.A.)--State University of New York at Binghamton, Dept. of Psychology, 2007. / Includes bibliographical references.
14

Functional asthma severity and impulsive behaviour in 6 and 7 year-old children : a dissertation submitted in partial fulfilment of the requirements for the degree of Master of Education (Child and Family Psychology) in the University of Canterbury /

Schuckard, Eeuwe. January 2007 (has links)
Thesis (M. Ed.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (leaves 105-115). Also available via the World Wide Web.
15

Impulse control impairments and non-referred conduct problems

Allan, Carla Counts, January 2005 (has links)
Thesis (M. S.)--Florida State University, 2005. / Advisor: Dr. Bryan R. Loney, Florida State University, College of Arts and Sciences, Dept. of Psychology. Title and description from dissertation home page (viewed Sept. 19, 2005). Document formatted into pages; contains vii, 42 pages. Includes bibliographical references.
16

The role of impulsive aggression in a cohort of suicide attempters

Hodges, Gayle Elizabeth. January 2006 (has links) (PDF)
Thesis (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2006. / Not embargoed. Vita. Bibliography: 90-100.
17

The effect of cognitive training on impulse control among Methamphetamine addicts in the Western Cape

Coetzee, Gert J. E. January 2016 (has links)
Magister Psychologiae - MPsych / Substance use addiction is a debilitating and destructive human disorder that affects millions of people worldwide. Of all the provinces in South Africa, the Western Cape has the highest rate of MA use. This highly addictive stimulant, locally known as 'tik', has multiple physiological, psychological, and social effects on the user. The effects are associated with neurocognitive deficits that include deficiencies in working memory and high rates of delay discounting. Current neuropsychopharmacology literature seems to suggest that changes in neurotransmitter functioning and particular brain areas occur that contribute to some of the addictive behaviours associated with chronic MA use. New evidence is emerging that working memory training can help to improve rates of impulsivity in those addicted to MA by strengthening cognitive control. The aim of this project was to establish whether differences in impulse control existed in a sample of 33 male patients at a Western Cape drug rehabilitation centre who received either working memory training with standard drug rehabilitation and or standard drug rehabilitation only. Data was collected with a self-report impulsivity scale (BIS – 11) and analysed using inferential statistics. The results suggest that working memory training, when paired with a standard rehabilitation program, has superior effects in decreasing self-reported rates of impulsivity when compared to standard rehabilitation only. These findings suggest that working memory training may serve as a useful addition to improving impulsivity rates in MA rehabilitation treatment. Further research on a larger scale is required to investigate the findings of this project.
18

On the Relation between Valence Weighting and Self-Regulation

Granados Samayoa, Javier Andre 12 October 2017 (has links)
No description available.
19

IOWA GAMBLING TASK PERFORMANCE IN CANADIAN FEDERAL OFFENDERS

Vedelago, Lana January 2020 (has links)
Rationale: Impulse control deficits are thought to underlie criminal offending. Impulsive choice is a facet of impulse control that refers to a preference for immediate over delayed rewards. This facet of impulse control has been measured empirically using the Iowa Gambling Task (IGT), which provides a metric of overall disadvantageous decision-making, as well as metrics of specific maladaptive decision-making strategies. Purpose: To investigate impulsive choice as a measure of impairment in offenders as reflected by performance on the IGT, and to examine maladaptive decision-making strategies that may mimic real-life decisions to engage in illegal behaviour. Methods: 100 Canadian federal offenders (34% female, mean age = 39.14 ± 9.74) and 89 controls (39% female, mean age = 37.04 ± 10.79) completed the IGT. The IGT involves repeatedly choosing cards from four decks. Two decks are “good” and result in a net gain on the task, and two decks are “bad” and result in a net loss. Decks offer a fixed reward, but vary in loss magnitude and frequency. IGT data were analyzed for net score (number of good choices minus number of bad choices), learning across the task, and deck switching patterns. Other assessments included data on offenders’ current sentence and risk for reoffence level. Results: Offenders performed significantly poorer than controls in terms of net score. Controls learned the advantageous strategy across the task but offenders did not. Offenders also made greater use of a “win-stay/lose-shift” strategy. Low-risk offenders performed significantly better than medium- or high-risk offenders on the IGT. Conclusion: These results suggest that, compared with controls, offenders tend to make riskier choices and use maladaptive decision-making strategies that provide a larger immediate reward but are disadvantageous in the long term. The IGT, as part of a comprehensive assessment of risk, may provide valuable information for preventing criminal offending and recidivism. / Thesis / Master of Science (MSc) / Criminal offending is thought to be related to impulse control problems. Research has linked offending to poor performance on a decision-making task known as the Iowa Gambling Task (IGT). On the IGT, participants repeatedly choose cards from four decks that provide wins and losses of points. Two decks are “good” and result in an overall gain on the task, and two decks are “bad” and result in an overall loss. In this study, 100 Canadian federal offenders and 89 non-incarcerated control participants completed the IGT. Offenders performed worse than the control group overall, and control participants but not offenders learned the best strategy (i.e., choosing from good decks) over the course of the task. Additionally, offenders with a “Low” criminal risk rating did better than those at “Medium” or “High” risk levels. These results suggest that the IGT may provide important information about the cause and prevention of criminal offending.
20

The Hierarchical Organization of Impulse Control: Implications for Decision Making

Coutlee, Christopher Gilbert January 2014 (has links)
<p>The research studies presented as this dissertation constitute a methodologically diverse and conceptually integrative approach to understanding impulsiveness in the context of cognitive control and decision making. Broadly, these findings address the validity of current conceptions of trait impulsiveness, relationships between those traits and brain or laboratory measures of cognitive control, and links between impulsive traits and economic decisions under conditions of delay or uncertainty. The findings presented in this thesis affirm the multidimensional nature of impulsiveness as a construct, and link individual differences in specific impulsive types to behavioral and neurobiological measures of control function. The nature of motor, attentional, and nonplanning impulsive types are contextualized by reference to evidence supporting a broad theory of behavioral control based on hierarchical organization of action, ranging from concrete acts to abstract plans and strategies. We provide evidence linking concrete forms of urgent/motor impulsiveness to behavior and brain activation during response-related control, and more abstract and future-oriented premedititative/nonplanning impulsiveness to strategic control signals in more rostral PFC. Finally, these findings are complemented by causal evidence from a neurostimulation study linking a contextual control network to risky decision making and attentional impulsiveness.</p> / Dissertation

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