Thesis (Ph. D.)--Ohio University, August, 1997. / Title from PDF t.p.

Thesis (Ph. D.)--Carnegie Mellon University, 2005. / "May 24, 2005." Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

La viabilité des systèmes de travail complexes repose en partie sur la capacité des opérateurs à y gérer des tâches concurrentes en fonction de leurs priorités respectives. Il s'agit là d'un processus critique qui, lorsqu'il est défaillant, peut amener à des erreurs de négligence ou de persévération sur certaines opérations. Les modèles actuels de la priorisation humaine présentent de nombreuses limites : ils sont souvent normatifs et ne rendent pas suffisamment compte de la façon dont les opérateurs utilisent effectivement l'information disponible dans l'environnement pour le calcul des priorités. Leur faible pouvoir descriptif ne permet pas réellement de comprendre les mécanismes cognitifs contributifs de l'erreur, spécialement dans des situations de surcharge mentale. Cette thèse, en adoptant l'approche de l'ergonomie cognitive, se donne pour objectif de mieux comprendre et décrire ces processus. Trois expérimentations fondamentales ont été menées, qui toutes mettaient les participants aux prises avec des situations de double-tâche, où divers attributs (difficulté, importance, marge d'erreur) des tâches étaient manipulés. Ces tâches reproduisaient des sollicitations des environnements complexes, comme la mémorisation, la surveillance, ou encore le diagnostic sous incertitude. L'ensemble des résultats souligne l'importance de la priorisation dans la bonne tenue des systèmes complexes, et suggère une sensibilisation accrue des opérateurs à ces phénomènes lors de leur formation, ainsi qu'une réflexion à plus long terme sur la présentation de l'information dans le contexte des interfaces homme-machine. / The viability of complex work systems depends in part on the ability of operators to manage competing tasks according to their respective priorities. This is a critical process which, when it fails, can lead to errors of negligence or perseverance on certain operations. Current models of human prioritization have many limitations: they are often normative and do not adequately account for how operators actually use the information available in the environment for computing priorities. Their weak descriptive power does not really make it possible to understand the cognitive mechanisms contributing to error, especially in situations of mental overload. This thesis, adopting the cognitive ergonomics approach, aims to better understand and describe these processes. Three fundamental experiments were conducted, all of which put participants in double-task situations, where various attributes (difficulty, importance, margin of error) of the tasks were handled. These tasks reproduced solicitations of complex environments, such as memorization, monitoring, or diagnosis under uncertainty. All the results underline the importance of the prioritization in the good behavior of the complex systems, and suggest an increased sensitization of the operators to these phenomena during their formation, as well as a longer-term reflection on the presentation of the information in the context of man-machine interfaces.

No description available.

Many people are more or less constantly connected through mobile technology today. This provides opportunities, but also makes people vulnerable for interruptions and prone to engage in multitasking, when full focus might be needed. Smartphone usage is common especially among younger people, making it interesting to investigate constant connectivity’s effect on learning. Previous studies have focused on quantifiable results regarding the effect on learning, such as impact on grades, but has not investigated the qualitative aspects. This thesis investigates students’ experiences regarding interruptions and multitasking through a three-part study. The results show that the impact is very context dependent and phone usage is occasionally not reflected upon. Further, the result indicates that being expected to always be available and respond quickly could be perceived as a problem. The findings presented in this thesis can contribute with important design implications for devices to enable single-task focus and avoiding interruptions.

Modern software systems have been pervasively concurrent to utilize parallel hardware and perform asynchronous tasks. The correctness of concurrent programming, however, has been challenging for real-world and large systems. As the concurrent events of a system can interleave arbitrarily, unexpected interleavings may lead the system to undefined states, resulting in denials of services, performance degradation, inconsistent data, security issues, etc. To detect such concurrency errors, concurrency testing repeatedly explores the interleavings of a system to find the ones that induce errors. Traditional systematic testing, however, suffers from the intractable number of interleavings due to the complexity in real-world systems. Moreover, each iteration in systematic testing adjusts the explored interleaving with a minimal change that swaps the ordering of two events. Such exploration may waste time in large homogeneous sub-spaces leading to the same testing result. Thus on real-world systems, systematic testing often performs poorly to reveal even simple errors within a limited time budget. On the other hand, randomized testing samples interleavings of the system to quickly surface simple errors with substantial chances, but it may as well explore equivalent interleavings that do not affect the testing results. Such redundancies weaken the probabilistic guarantees and performance of randomized testing to find any errors. Towards effective concurrency testing, this thesis leverages partial order semantics with randomized testing to find errors with strong probabilistic guarantees. First, we propose partial order sampling (POS), a new randomized testing framework to sample interleavings of a concurrent program with a novel partial order method. It effectively and simultaneously explores the orderings of all events of the program, and has high probabilities to manifest any errors of unexpected interleavings. We formally proved that our approach has exponentially better probabilistic guarantees to sample any partial orders of the program than state-of-the-art approaches. Our evaluation over 32 known concurrency errors in public benchmarks shows that our framework performed 2.6 times better than state-of-the-art approaches to find the errors. Secondly, we describe Morpheus, a new practical concurrency testing tool to apply POS to high-level distributed systems in Erlang. Morpheus leverages dynamic analysis to identify and predict critical events to reorder during testing, and significantly improves the exploration effectiveness of POS. We performed a case study to apply Morpheus on four popular distributed systems in Erlang, including Mnesia, the database system in standard Erlang distribution, and RabbitMQ, the message broker service. Morpheus found 11 previously unknown errors leading to unexpected crashes, deadlocks, and inconsistent states, demonstrating the effectiveness and practicalness of our approaches.

The aim of this paper is to investigate how media-multitasking (MMT) affects cognitive abilities, particularly concentration. MMT is becoming increasingly popular, especially among those aged 16-25, and concerns have been raised about its impact on attention spans, particularly with the widespread use of the social media app TikTok. To explore this relationship, a test group of 26 computer science and media technology students were asked to watch a video and answer questions based on it. The participants were divided into three groups that performed the test with varying levels of visual multitasking. The results showed that multitasking had a slight negative impact on cognitive ability, with better performance on visual questions when participants were not multitasking, and better performance on sound-based questions when they were multitasking. Overall, the study suggests that while multitasking can overload certain senses, it can also enhance alertness and concentration if not taken to cognitive overload. / Syftet med denna uppsats är att undersöka hur media-multitasking (MMT) påverkar hjärnans olika kognitiva modaliteter, dvs olika former av kognitivt uppfattande eller sätt att bearbeta information, och då kopplat specifikt till koncentration. MMT blir allt mer populärt och särskilt bland personer i åldrarna 16-25. Oro har väckts kring hur MMT påverkar uppmärksamheten, särskilt vid användning av den sociala appen TikTok. För att undersöka detta förhållande bads en testgrupp, bestående av 26 studenter inom datavetenskap och medieteknik, att titta på en video samt besvara frågor baserade på den. Deltagarna delades in i tre grupper som utförde testet på olika nivåer av visuell multitasking. Resultatet visade att multitasking hade en minimal till oansenlig negativ påverkan på prestation inom de provade modaliteterna. Deltagarna presterade bättre på visuella frågor när deltagarna inte multitaskande. Resultatet visade att svaren på de ljudbaserade frågorna förbättrades till viss del när testgruppen multitaskade. Sammantaget kan studien inte dra några säkra slutsatser, men det finns indikationer på att multitasking kan överbelasta vissa sinnen samtidigt som det kan underlätta för individer att förbli alerta och därmed förbättra koncentrationen, förutsatt att det inte leder till kognitiv överbelastning.

This study examines adolescent students at an American international school and observes student use of social networking programs as well as physical actions in the search process. The study specifically observed multitasking behavior and organizational skills among students, as well as linkages made through social networking sites. Student observations, student interviews, analysis of Facebook entries, and a survey on multitasking yielded rich data. Students appear to be far more organized than previously suggested in the literature, and in this study, the organization proved to be largely self-taught. Students used their social networks to build a kind of group expertise that compensated for their youthful naivety. Students exhibited self-control within the search to the degree that they could focus on what they wanted to find, and they used heuristics—mental shortcuts—to achieve what they needed. Searches also suggest creativity in that students were flexible in their search methods and used a number of tools to gather information. Students could balance the needs of the academic or imposed search with their own online lives, meaning that they made compensations for social media and media multitasking when it was deemed necessary.

A number of studies have explored the impact of multitasking on specific cognitive skills, primarily with regard to non-media multitasking activities. While briefly addressing technology, its use in the modern era regarding media multitasking and its associated cognitive declines has not been extensively examined. Forty-nine participants were required to complete a series of cognitive tasks including the Stroop Color and Word Test and the Trail Making Test. Data were also collected for how often participants media multitask, the amount of technology they use, as well as other demographic variables. The goal of this study was to empirically examine the role of technology use and media multitasking on cognitive processes such as selective attention and task switching. It was hypothesized that those grouped as high media-multitaskers would predict a faster reaction time on the Stroop task, in line with previous literature by Cain & Mitroff (2011). Results showed a significant relationship exhibiting a negative correlation between the two factors, thereby accepting the hypothesis. Findings conclude with considerations for both the use and design of technological interfaces and devices as they apply to a variety of operational settings and high-tech environments.