No description available.

Studier visar att det framför allt är äldre som lever i ett digitalt utanförskap i Sverige. Många pensionärer behöver hjälp att utföra digitala aktiviteter och däribland att handla online. Detta tyder på att det finns ett behov av att anpassa digitala medier till äldre. Denna studie ämnar således fördjupa förståelsen för det digitala utanförskapet, och de faktorer som påverkar seniorers intentioner och möjligheter att handla online. Detta för att sedan granska på vilket sätt anpassningar av onlinehandeln kan öka seniorers intention att handla online. Faktorerna baseras på modellen Unified Theory of Acceptance and Use of Technology (UTAUT) och teorin Innovation Resistance Theory (IRT) och testas genom 12 teser. En metodkombination har använts, vilket har genererat 97 enkätsvar och 4 intervjuer, vilka har genomförts på seniorer över 55 år. Resultatet visar att svenska seniorer idag lever i ett digital utanförskaps på grund av ett ointresse och okunskap för den digitala tekniken. Studien visar att icke-användare har fler barriärer och färre drivkrafter i förhållande till användare. Användarna har överkommit barriärerna och har drivkrafterna som påverkar deras intention att handla online positivt. Således kan drivkrafterna användas för att överkomma barriärerna. Detta bör göras genom anpassningar i form av utbildningar, utformning av tydliga hemsidor, tillgänglighetsanpassad kundservice och säkra leveransprocesser. / It is mainly the elderly who lives in a digital exclusion in Sweden. Many elderly needs help to carry out digital activities, including online shopping. This suggests that there is a need to adapt digital media to the elderly. This study intends to deepen the understanding of digital exclusion, and the factors that influence seniors' intentions and opportunities to shop online. The study will then examine how adjustments to online shopping can increase seniors' intention to shop online. The factors are based on the Unified Theory of Acceptance and Use of Technology model (UTAUT) and the Innovation Resistance Theory (IRT) and is tested through 12 theses. A combination of methods conducted on seniors aged 55 and over generated 97 survey responses and 4 interviews. The result shows that Swedish seniors today live in a digital exclusion due to a lack of interest and knowledge of digital technology. The study indicates that non-users have more barriers and fewer driving forces in relation to users. The users overcome the barriers by utilizing driving forces which positively influence their intention to shop online. Therefore, the driving forces can be used to overcome the barriers. This should be done through adaptations in the form of education, design of distinct websites, accessible customer service and secure delivery processes.

Les militaires canadiens sont souvent confrontés à des situations stressantes et une partie de ceux-ci rapportent avoir des troubles du sommeil et faire des cauchemars. Depuis 2006, un traitement basé sur l’Imagery Rehearsal Therapy (IRT) nommé « groupe de traitement du sommeil » (GTS) est offert à la base de Valcartier pour traiter les troubles du sommeil et les cauchemars. Le GTS intégral inclut un volet psychoéducatif (une séance) et un volet traitement des cauchemars (deux séances). Les militaires aux prises avec un trouble du sommeil qui ne font pas de cauchemars sont dirigés vers le volet psychoéducatif du GTS donné seul (une séance). La présente étude a pour but d’évaluer l’efficacité du GTS auprès des militaires canadiens et poursuit quatre objectifs de recherche. Le premier est d’évaluer l’effet de la participation au GTS intégral sur le sommeil et les cauchemars. Le deuxième objectif est d’évaluer l’effet de la participation au volet psychoéducatif donné seul sur le sommeil. Le troisième objectif est d’évaluer l’effet de la participation au GTS intégral sur les symptômes associés à l’état de stress post-traumatique (ESPT), à l’anxiété et à la dépression. Enfin, le dernier objectif est d’évaluer l’effet de la participation au volet psychoéducatif donné seul sur les symptômes d’ESPT, d’anxiété et de dépression. L’échantillon de 37 militaires est réparti en quatre groupes. Deux groupes sont formés de participants liés au GTS intégral, soit un groupe expérimental (11 participants) et un groupe contrôle (trois participants), et deux groupes sont formés de participants liés à la psychoéducation donnée seule, soit un groupe expérimental (17 participants) et un groupe contrôle (six participants). Les groupes contrôle sont formés de participants sur la liste d’attente du GTS. Les mesures (prétest et post-test) incluent des agendas du sommeil (qualité du sommeil, nombre d’heures de sommeil, nombre et intensité des cauchemars) et trois questionnaires : PCL C (symptômes post-traumatiques), IDB-II (symptômes dépressifs) et IAB (symptômes d’anxiété). Les dossiers médicaux des participants ont aussi été consultés (données sociodémographiques et traitements psychothérapeutiques et pharmacologiques). Étant donné la taille limitée de l’échantillon, des tests non paramétriques (p. ex. test de Wilcoxon, etc.) ont été effectués afin de vérifier les changements entre le prétest et le post-test et pour comparer les groupes expérimentaux aux groupes contrôle. À la suite du GTS intégral, une amélioration significative de la qualité du sommeil et une diminution significative du nombre de cauchemars ont été rapportées, et ces améliorations sont significativement supérieures à ce qui est observé après le passage du temps. On observe aussi une augmentation significative du nombre d’heures de sommeil et une diminution significative de l’intensité des cauchemars à la suite du GTS intégral. Après la psychoéducation donnée seule, les résultats indiquent une augmentation significative du nombre d’heures de sommeil et une amélioration significative des symptômes dépressifs. Le GTS nécessite peu de temps et peu de ressources. Sachant que plusieurs militaires canadiens ont un problème de sommeil ou de cauchemars, les résultats de la présente étude indiquent que le GTS peut être une solution efficiente pour traiter les troubles du sommeil et les cauchemars.

Twelve step organizations such as Alcoholics Anonymous and Narcotics Anonymous are free, community-based fellowships. Such organizations are the most widely sought recovery management options, surpassing professional treatment. The emerging evidence base suggests that involvement in such organizations is associated with positive substance-related outcomes (e.g., abstinence). Relatively speaking, however, far less is known about whether or not involvement is associated with other meaningful psychosocial constructs. The current study examined gratitude, meaning in life, life satisfaction, personal growth, and various other recovery and psychosocial constructs in a sample of self-identified NA members (N = 128) from 26 U.S. states, ranging in age from 22 to 64 years. The primary aim of the present study was to psychometrically evaluate and refine four distinct positive psychology instruments (i.e., Gratitude Questionnaire (GQ – 6), Meaning in Life Scale (MLQ), Satisfaction With Life Scale (SWLS), Personal Growth Initiative Scale (PGIS)). The current study contained three phases. First, the psychometric properties of each instrument were examined within an Item Response Theory measurement framework. The Rating Scale Model was used to evaluate the each instrument using WINSTEPS 3.74.01. With the exception of the Meaning in Life Questionnaire (which did not conform to an IRT measurement model), each instrument was iteratively refined based on statistical and clinical considerations, resulting in the collapse of response options and the removal of poorly fitting items. These refinements improved the psychometric properties of each instrument, resulting in a more reliable, accurate, and efficient way to measure gratitude, life satisfaction, and personal growth in clinical samples. Second, items from the GQ – 6, SWLS, and PGIS were examined concurrently using the PROC IRT procedure in SAS to explore whether the constructs were distinct from one another. Results provide support that gratitude, life satisfaction, and personal growth are unique and distinct constructs. Last, the study examined several recovery-related correlates of gratitude, life satisfaction, and personal growth. Hierarchical regression models assessed whether abstinence duration and other recovery-related variables accounted for significant incremental variance in gratitude, life satisfaction, and personal growth, over and above several covariates. As a block, abstinence duration and recovery predictors accounted for significant incremental variance in all of the constructs. These data suggest ongoing recovery involvement in 12-step organizations may be associated with positive outcomes beyond abstinence. Limitations and directions for future research are discussed.

A Monte Carlo simulation study investigated the effect of scoring format, item parameterization, threshold configuration, and prior ability distribution on the accuracy of ability estimation given various IRT models. Item response data on 30 items from 1,000 examinees was simulated using known item parameters and ability estimates. The item response data sets were submitted to seven dichotomous or polytomous IRT models with different item parameterization to estimate examinee ability. The accuracy of the ability estimation for a given IRT model was assessed by the recovery rate and the root mean square errors. The results indicated that polytomous models produced more accurate ability estimates than the dichotomous models, under all combinations of research conditions, as indicated by higher recovery rates and lower root mean square errors. For the item parameterization models, the one-parameter model out-performed the two-parameter and three-parameter models under all research conditions. Among the polytomous models, the partial credit model had more accurate ability estimation than the other three polytomous models. The nominal categories model performed better than the general partial credit model and the multiple-choice model with the multiple-choice model the least accurate. The results further indicated that certain prior ability distributions had an effect on the accuracy of ability estimation; however, no clear order of accuracy among the four prior distribution groups was identified due to an interaction between prior ability distribution and threshold configuration. The recovery rate was lower when the test items had categories with unequal threshold distances, were close at one end of the ability/difficulty continuum, and were administered to a sample of examinees whose population ability distribution was skewed to the same end of the ability continuum.

Sleep disturbances are a core and salient feature of PTSD and can maintain or exacerbate associated symptoms. Recent research demonstrates that cognitive-behavioral sleep-focused interventions improve sleep disturbances as well as PTSD symptoms. The present study is a randomized controlled trial comparing Cognitive Behavioral Therapy for Insomnia (CBT-I) to a waitlist control group. Conducted at a Veterans Affairs Medical Center, the study: 1) compared subjective outcome measures of sleep amongst veterans assigned to either a treatment group (CBT-I) or a waitlist control group; (2) examined the influence of the intervention on measures of PTSD, general mood and daytime functioning, comparing veterans in a treatment group to those in a waitlist control group and (3) examined the effect of the CBT-I intervention using objective measures of sleep for veterans included in the treatment arm of the study. Study participants were (n = 40) combat veterans who served in Afghanistan and/or Iraq (OEF/OIF). Participants were randomized to either a CBT-I treatment group or a wait-list control group. Those in the treatment condition participated in four CBT-I sessions over six weeks. CBT-I included sleep restriction, stimulus control, cognitive restructuring, sleep education, sleep hygiene and imagery rehearsal therapy. All participants completed subjective and objective measures at baseline and post-treatment. At six weeks post treatment, veterans who participated in CBT-I reported improved sleep, a reduction in PTSD symptom severity and PTSD-related nightmares, as well as a reduction in depression and distressed mood compared to veterans in the waitlist control group. When controlling for current participation in evidence-based PTSD treatment, veterans in the CBT-I group reported a reduction in PTSD symptom severity while their waitlist counterparts demonstrated an increase in these PTSD symptoms. Veterans in the treatment group also reported improved objectively measured sleep quality between baseline and posttreatment. These data suggest that CBT-I is an effective treatment for insomnia, nightmares and PTSD symptoms in OEF/OIF veterans with combat related PTSD and should be used as an adjunctive therapy to standard PTSD treatment.

Les objectifs de cette thèse sont la validation d’une méthodologie de détermination de la température de surface (LST) et de l’émissivité de surface (LES) à partir des radiances hyperspectrales du capteur IASI à bord du satellite METOP. Il s’agit de montrer la possibilité d’extraire ces deux paramètres d’un signal hyperspectral IRT télédétecté dans une approche physique. Le domaine spectral d'étude s'étend de 750 à 1250 cm-1 (8 à 13,3 μm) et la résolution spectrale est de l'ordre du 0,25 cm-1, inscrivant ainsi ce travail dans le giron de la radiométrie à très haute résolution spectrale infrarouge. Après une étude des méthodes de séparation existantes, la méthode SpSm (Spectral Smothness), est validée. Une étude de sensibilité aux erreurs aux bruits atmosphérique et instrumental est menée. La méthode SpSm est appliquée aux données IASI en conditions réelles pour l’année 2008 dans une zone spatiale couvrant l’Europe et le Nord d’ Afrique. Les résultats sont validés d’une part avec les produits MODIS et SEVIRI, et d’autre part avec les paramètres température et émissivité obtenus à partir des radiances SEVIRI et l’algorithme TISI. / This thesis focuses on the validation of a methodology for determining the surface temperature (LST) and surface emissivity (LES) from hyperspectral radiances from the IASI sensor on board of the European satellite METOP. We show that it is possible to extract these two parameters from a remotely sensed TIR signal using a physical approach. The spectral range under study extends from 750 to 1250 cm-1 (8 to 13.3 μm) and the spectral resolution is 0.25 cm-1, placing this work in the context of very high spectral resolution infrared radiometry. After studying the existing methods of separation, the SpSm method (Spectral Smothness), is validated. A study of sensitivity to atmospheric and instrumental noise is conducted. The SpSm method is applied to the IASI data in real conditions in 2008 in a spatial area that covers Europeand North Africa. The results are validated on one hand with the MODIS and SEVIRI products, and on the otherhand with temperatures and emissivities obtained from the SEVIRI radiances and the TISI algorithm.

The No-U-Turn Sampler (NUTS) is a relatively new Markov chain Monte Carlo (MCMC) algorithm that avoids the random walk behavior that common MCMC algorithms such as Gibbs sampling or Metropolis Hastings usually exhibit. Given the fact that NUTS can efficiently explore the entire space of the target distribution, the sampler converges to high-dimensional target distributions more quickly than other MCMC algorithms and is hence less computational expensive. The focus of this study is on applying NUTS to one of the complex IRT models, specifically the two-parameter mixture IRT (Mix2PL) model, and further to examine its performance in estimating model parameters when sample size, test length, and number of latent classes are manipulated. The results indicate that overall, NUTS performs well in recovering model parameters. However, the recovery of the class membership of individual persons is not satisfactory for the three-class conditions. Also, the results indicate that WAIC performs better than LOO in recovering the number of latent classes, in terms of the proportion of the time the correct model was selected as the best fitting model. However, when the effective number of parameters was also considered in selecting the best fitting model, both fully Bayesian fit indices perform equally well. In addition, the results suggest that when multiple latent classes exist, using either fully Bayesian fit indices (WAIC or LOO) would not select the conventional IRT model. On the other hand, when all examinees came from a single unified population, fitting MixIRT models using NUTS causes problems in convergence.

To ensure test security and fairness, alternative forms of the same test are administered in practice. However, alternative forms of the same test generally do not have the same test difficulty level, even though alternative test forms are designed to be as parallel as possible. Equating adjusts for differences in difficulties among forms of the test. Six traditional equating methods are considered in this study: equipercentile equating without smoothing, equipercentile equating with pre-smoothing and post-smoothing, IRT true-score and observed-score equatings, and kernel equating. A common feature of all of the traditional procedures is that the end result of equating is a single transformation (or conversion table) that is used for all examinees who take the same test. Van der Linden has proposed conditional equipercentile (or local) equating (CEE) to reduce the error of equating contained in the traditional equating procedures by introducing individual level equating. Van der Linden's CEE is conceptually closest to IRT-T in that CEE is with respect to a type of true score (θ, or proficiency), but it shares similarities with to IRT-O in that CEE uses an estimated observed score distribution for each individual θ to equate scores using equipercentile equating. No real-data study has yet compared van der Linden's CEE with each of the traditional equating procedures. Indeed, even for the traditional procedures, no study has compared all six of them simultaneously. In addition to van der Linden's CEE, two additional variations of CEE are considered: CEE using maximum likelihood (CEE-MLE) and CEE using the true characteristic curve (CEE-TCC). The focus of this study is on comparing results from CEE vis-à-vis the traditional procedures, as opposed to answering a “best-procedure”question, which would require a common conception of “true”equating. Although the results of the traditional equating methods are quite similar, the kernel equating method and equipercentile equating with log-linear presmoothing generally show better fit to the respective original form statistical moments under various data conditions. Although IRT-T and IRT-O usually are found to be least favorable under all circumstance in terms of statistical moments, the equated raw score difference distribution illustrates more stable performance than traditional equating methods. It was found here that the number of examinees having a particular score point does not influence results for CEE as much as it does for traditional equatings. CEE-EAP and CEE-MLE are very similar to one another and the equated score difference distributions are similar to those of IRT-O. CEE-TCC involves a part of the IRT-T procedure. Hence, CEE-TCC behaves somewhat similar to IRT-T. Although CEE results are less desirable in terms of maintaining statistical moments, the equated score differences are more consistent and stable than for the traditional equating methods.

Equating is a statistical process used to accomplish score comparability so that the scores from the different test forms can be used interchangeably. One of the most widely used equating procedures is unidimensional item response theory (UIRT) equating, which requires a set of assumptions about the data structure. In particular, the essence of UIRT rests on the unidimensionality assumption, which requires that a test measures only a single ability. However, this assumption is not likely to be fulfilled for many real data such as mixed-format tests or tests composed of several content subdomains: failure to satisfy the assumption threatens the accuracy of the estimated equating relationships. The main purpose of this dissertation was to contribute to the literature on multidimensional item response theory (MIRT) equating by developing a theoretical and conceptual framework for true-score equating using a simple-structure MIRT model (SS-MIRT). SS-MIRT has several advantages over other complex MIRT models such as improved efficiency in estimation and a straightforward interpretability. In this dissertation, the performance of the SS-MIRT true-score equating procedure (SMT) was examined and evaluated through four studies using different data types: (1) real data, (2) simulated data, (3) pseudo forms data, and (4) intact single form data with identity equating. Besides SMT, four competitors were included in the analyses in order to assess the relative benefits of SMT over the other procedures: (a) equipercentile equating with presmoothing, (b) UIRT true-score equating, (c) UIRT observed-score equating, and (d) SS-MIRT observed-score equating. In general, the proposed SMT procedure behaved similarly to the existing procedures. Also, SMT showed more accurate equating results compared to the traditional UIRT equating. Better performance of SMT over UIRT true-score equating was consistently observed across the three studies that employed different criterion relationships with different datasets, which strongly supports the benefit of a multidimensional approach to equating with multidimensional data.