| 1. |
- Castor, Martin, 1972-
(författare)
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The use of structural equation modeling to describe the effect of operator functional state on air-to-air engagement outcomes
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Computational evidence of the operative usefulness of a new system is crucial in large system development processes concerning billions of euros or dollars. Although it is obvious that the human often is the most important and critical component of many systems, it has often been hard for Human Factors researchers to express human aspects in a computational and strict way. The thesis describes, through data based statistical modeling, how the concepts or constructs of sensor effectiveness, usability of information, mental workload, situation awareness and teamwork relates to each other and to the operative performance in a fourship of fighter pilots. Through the use of structural equation modeling, ad modum LISREL, a statistical model that describes how the operators’ functional state mediates the effects between technical system oriented variables, was developed.The constructs used in the modeling process have received widespread scientific and operational attention. They have also been identified as multi-dimensional. Many different ways of measuring them have been developed in the scientific community, and the thesis focuses on the next step, i.e. how do these higher order constructs relate to each other in something as multi-dimensional as human activity in real situations?A comprehensive human factors related dataset was collected in a large simulation based acquisition study that examined the requirements and properties of aircraft radar systems. The dataset contains 308 simulated engagements with data from four pilots each, i.e. 1232 cases in a database with 24 variables, generated by 37 pilots. The collected data and the resulting models thus summarizes more than 700 hours of experienced pilots’ complex behavior in an operationally valid environment, and in a way that is of theoretical interest as well as of importance in system development processes. The data thus comes from a real world study of complex processes in a dynamic context, although from a simulator. The thesis is a case example of modern ecologically valid experimental psychology. The data collection does not represent a classical experimental setup, but instead demonstrates methodological needs and considerations for human factors practitioners when working in system development studies. The fact that parts of the used data are classified has not affected the models and scientific conclusions, although the practical findings have been partly circumscribed in the presentation.As a result of the statistical modeling effort, a structural equation model of how the chosen constructs relate to each other, and mediate effects between technical measures by a model of the operator, is proposed. Simplicity of the model was the goal, and based on former experiences and findings, a simplex structure was hypothesized. The final model shows that the covariances between the 24 measures can be explained by a quasi-simplex structure of seven factors.
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| 2. |
- Jonsson, Ing-Marie, 1960-
(författare)
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Social and Emotional Characteristics of Speech-based In-Vehicle Information Systems : Impact on Attitude and Driving Behaviour
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modern vehicles use advanced information systems in vehicles to provide and control a wide variety of functions and features. Even modest vehicles today are equipped with systems that control diverse functions from air-conditioning to high quality audio/video systems.Since driving requires the use of eyes and hands, voice interaction has become more widely used by in-vehicle systems. Due to the technical complexity involved in voice recognition, focus has been on issues of speech ecognition. Speech generation is comparatively simple, but what effect does the choice of voice have on the driver? We know from human-human interaction that social cues of the voice itself influence attitude and interpretation of information. Introducing speech based communication with the car changes the relationship between driver and vehicle. So, for in-vehicle information systems, does the spoken voice matter?The work presented in this thesis studies the effects of the voice used by invehicle systems. A series of studies were used to answer the following questions: Do the characteristics of voices used by an in-vehicle system affect driver’s attitude? Do the characteristics of voice used by an in-vehicle system affect driver’s performance? Are social reactions to voice communication the same in the car environment as in the office environment?Results show that voices do matter! Voices trigger social and emotional effects that impact both attitude and driving performance. Moreover, there is not one effective voice that works for all drivers. Therefore an in-vehicle system that knows its driver and possibly adapts to its driver can be the most effective. Finally, an interesting observation from these studies is that social reactions to voice communication in the car are different than in the office, Similarity attraction, an otherwise solid finding in social science, did not hold all studies. It is hypothesized that this difference can be related to the different kinds of task demands when driving a car or working in an office environment.
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| 3. |
- Berggren, Peter, 1971-
(författare)
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Assessing Shared Strategic Understanding
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes the development of an instrument for assessing shared understanding in teams. The purpose was to develop an instrument that would be usable, understandable, objective, flexible and self-explanatory. Teams working in naturalistic settings are expected to have a shared understanding concerning common goals and how to achieve these. The problem investigated in this thesis is that current techniques and instruments for assessing shared understanding in teams generally suffer from one or more of the following drawbacks, namely that they are expensive, difficult to use, time-consuming, requiring expertise, and are often based on subjective perceptions. Departing from existing theory in team cognition techniques and theories, the research questions posed in this thesis are: 1) How can shared understanding be measured without the disadvantages of existing methods? 2) How can shared understanding be assessed without the bias of self-ratings and/or assessments by experts/observers? 3) Can team performance be better understood by the outcomes of an instrument that measures shared understanding?These research questions are answered through six studies that are presented in this thesis. Over the six studies an instrument was iterated and subsequently developed, called the “shared priorities instrument”. When using this instrument, team members are instructed to generate items and rank these in order of importance. By comparing these rank orders from different participants, a team measure of shared understanding can be calculated. The advantages of this instrument compared to earlier measures are that it is less expensive, easier to use, less time-consuming, does not require subject matter expertise, and that the instrument is distanced from subjective perceptions. Furthermore, the final study provides results where outcomes from the shared priorities instrument correlate with performance, supporting earlier research connecting shared understanding in teams with team performance. A structural equation model, a result of the final study, shows that the instrument is both valid and reliable.
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| 4. |
- Ekberg, Joakim, 1976-
(författare)
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Online health promoting communities : Design, implementation and formative evaluation of an intervention
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden, obesity among children has not yet reached the epidemic proportions reported from other parts of the world. However, among adolescents, being overweight and self-consciousness regarding body shape, diet and exercise influence social, psychological and physical health. Obese children may be in need of secondary prevention because of adverse effects related to obesity, but it is less obvious exactly what to prevent in the rest of the population. General interventions to prevent overweight and obesity are problematic because of the lack of associations for general application; there is a need for personalized community-based health promotion. Online interventions are especially suitable considering the amount of time adolescents spend online.This thesis takes a design approach to interventions and describes the design of an online health promoting community as a path to health promotion among adolescents. The first two studies use data from the first 15 years of a 1991 cohort living in Östergötland to determine the predictability of obesity from childhood body mass index and to investigate interventions and available evidence to suggest appropriate interventions. The next two studies use these findings to design and formatively evaluate a health promotion intervention.In Study I we found reasons for offering population-based interventions systematically from 5 years of age. It would be worthwhile identifying at an early age those relatively few children with substantially increased risk of maintaining obesity in adulthood and offering them interventions; but interventions must be avoided when they are not necessary. The projections in Study II indicate that more specified interventions would benefit adolescents without increasing the costs. In Study III, we found than an online health promoting community can be designed simply at relatively low cost and can be negotiated to satisfy both the needs of the user community and public health goals and service capabilities. In Study IV, a checklist for pre-launch evaluation of online health promoting communities was developed and the most important result was the delicate balance between community autonomy and quality control. Future studies addressing health outcome constructs for use in online health promoting community evaluations are warranted.
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| 5. |
- Magnusson Nählinder, Staffan, 1971-
(författare)
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Flight Simulator Training : Assessing the Potential
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mental workload is an important concept and has been proven to be a precursor to situation awareness and operative performance. This thesis describes methods to measure mental workload through self-ratings and psychophysiological measurements. Similarities and differences in psychophysiological reactions and rated mental workload between simulated and real flights are described. The consequences of such similarities and differences are discussed and its possible effect on training potential.A number of empirical studies are presented. They describe the experience and the psychophysiological reactions of pilots flying in a simulator and in real flight. In most cases, the reactions are similar – there is a high degree of accordance in rated mental workload and psychophysiological reaction between simulated and real flight. The studies show, that even though the responses are similar, there are also interesting differences. In one study, the pilots have consistently lower heart rate, higher heart rate variability and less eye movements in the simulator than in real flight. In another study, during certain events, the pilots have higher heart rate in the simulator than in real flight. The results are important in order to understand the training potential of simulators from a human factors perspective. Further, two measurement equipments for psychophysiological recording are compared and various psychophysiological measures are tested in applied settings.The thesis also discusses some methodological aspects, such as methods to create reliable and valid variables in dynamic applied research and how to deal with individual differences. An algorithm is suggested to remove differences between individuals. This facilitates the finding of within-participant effects.Finally, results from a study on embedded training tools are presented. In this study, student pilots and instructors rated the usefulness of several embedded training tools. These tools were built into a simulator to facilitate learning and teaching by illustrating concepts that can be difficult to understand. The results show clearly that such training tools are appreciated by both students and instructors. Well implemented, thoroughly selected training tools can dramatically improve the training potential of future training simulators.
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| 6. |
- Forsblad (Kristiansson), Mattias, 1985-
(författare)
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Distributed cognition in home environments : The prospective memory and cognitive practices of older adults
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis I explore how older people make use of, and interact with, their physical environment in home and near-by settings to manage cognitive situations, specifically prospective memory situations. Older adults have in past research been shown to perform better on prospective memory in real-life settings than what findings in laboratory-like settings predict. An explanation for this paradox is that older adults has a more developed skill of using the environment for prospective memory than younger adults. However, research investigating this explanation has primarily been based on self-reports.I contribute to the understanding of this skill by doing two related things. First I introduce distributed cognition, a theoretical perspective that primarily has been used within professional and socio-technical environments, to the research field of prospective memory in everyday life. Second I present a cognitive ethnography conducted during two years across eight home, and near-by, environments and old-age retired persons, for which I have used theoretical concepts from distributed cognition to analyze observations.The analysis shows rich variations in how participants use common cultural cognitive tools, invent their own cognitive tools, deliberately and incidentally shape more or less functional spaces, make use of other physical features, orient themselves toward and make sense of cognitive resources. I complement both prospective memory and distributed cognition research by describing both the intelligent shaping and use of space. Furthermore, by taking a distributed cognitive perspective I show that prospective memory processes in home environments involve properties, and the management, of a multipurpose environment.Altogether this supports the understanding of distributed cognition as a perspective on all cognition. Distributed cognition is not a reflection of particular work practices, instead it is a formulation of the general features of human cognition. Prospective memory in everyday life can be understood as an ability persons have. However, in this thesis I show that prospective memory can also be understood as a process that takes place between persons, arrangements of space, and tools.
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