Thesis (Ph. D.)--University of Wisconsin--Madison, 1974. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph. D.)--Washington State University, May 2006. / Includes bibliographical references (p. 130-134).

Thesis (B.Sc)--University of Hong Kong, 2002. / "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, May 10, 2002." Also available in print.

The following thesis is written by students at the School of Engineering at Jönköping University, informatics, New Media Design. The background of this report is based on a project collaboration with Toxic Interactive solutions AB, who wanted help with creating an application for registering sick leave from work. Since these registrations for sick leave affects the income and work relations, the aspect trust within an application was chosen as a subject for the report. Furthermore we connected this to the feedback element to see how trust was affected by this factor. Also the design and tonality of the feedback was chosen as a subject for the study. Visual feedback connects to the user with information about their actions and a confirmation. Based on this, two questions were formed: [1] How does visual feedback affect trust in a mobile application? [2] Does the the tonality in the feedback affect trust for a mobile application? To answer these questions, user tests and interviews was performed with the users. Three prototypes were created with different levels of feedback: no feedback, feedback with formal tonality and feedback with informal tonality. These were tested on nine users for each prototype (27 users in total). Parallelly two interviews with experts of the area were performed for a deeper knowledge and comparability. Other than this relevant studies and theories have been studied. The results of this study show that feedback contributes to increased trustworthiness amongst users. Although there are many other reasons that will have an affect. A formal tonality in the feedback is perceived as slightly more trustworthy according to the user tests and user interviews conducted. An insight about the connection between the tonality and target groups and subjective preferences was revealed from the expert interviews. Also, theories studied about the formality of the language mentions that it should be adapted to the specific target group. The conclusions that can be made from the study shows that trust, feedback and tonality are all connected. all the results show that feedback in a system has a positive effect on the user experience. Feedback also means more trust from a user than when its absent. / Följande examensarbete har utförts av studenter på Tekniska Högskolan i Jönköping på kandidatpåbyggnadsprogrammet informatik, New Media Design. Bakgrunden till arbetet grundar sig i ett projekt från Toxic Interactive Solutions AB som önskade hjälp med att ta fram en mobilapplikation för hantering av sjukanmälningar. Eftersom sjukanmälningar påverkar inkomst och jobbrelationer var förtroende en aspekt som valdes som inriktning att studera. Vidare hur förtroende hos användare påverkas av feedback. Även hur feedbacken är utformad valdes att studera. Visuell feedback återkopplar till användare om deras utförda handlingar som en bekräftelse på att deras anmälningar i applikationen är genomförda. Grundat i detta formulerades två frågeställningar: [1] Hur påverkar visuell feedback i ett gränssnitt faktorn förtroende för en mobilapplikation? [2] Påverkar tonaliteten i feedbacken förtroendet för en mobilapplikation? För att besvara dessa frågeställningar utfördes observationer användartester uppföljt av intervjuer med användarna. Tre prototyper utformades med olika grad av feedback; ingen feedback, formell ton på feedback samt icke-formell ton på feedback. Dessa testades med 9 personer på varje prototyp för att utläsa eventuella skillnader på attityd till dem (totalt 27 tester/intervjuer). Parallellt utfördes två olika intervjuer med experter inom området för att få en djupare kunskap, samt att kunn jämföra med användartesterna. Utöver detta har relevanta studier och teorier studerats. Resultaten visar på att feedback bidrar till ökat förtroende, dock är det många olika aspekter som spelar in. En formell tonalitet i feedbacken upplevdes aningen mer pålitlig enligt användartester och användarintervjuer. En insikt om att detta är starkt kopplat till målgrupp och subjektiva preferenser konstaterades från båda expertintervjuerna som hölls. Även teori om formalitet i språk säger att språket bör anpassas till den specifika användaren. De slutsatser som kan utläsas från studien är att förtroende, feedback och tonalitet går att koppla till varandra. Samtliga delar tyder på att användning av feedback har en positiv inverkan på användarupplevelsen. Även när feedback är närvarande inger detta mer tillit än när den inte är befintlig.

Syftet med denna studie är att ta reda på vad som skulle motivera studenter att använda sig av en gamifierad plattform för att ge varandra formativ feedback. Studien är utformad som en fallstudie där studiens utgångspunkt är studenternas behov av en möjlig gemensam plattform för att enklare kunna be varandra om hjälp i programmeringskurser. Men Studien och det efterföljande resultatet kan även appliceras på andra kurser. Användningen utav både kvalitativa och kvantitativa datainsamlingsmetoder har genomförts, detta i form utav intervjuer och enkäter samt en testning av en gamifierad plattform. Då det insamlade datat är av kvalitativ och kvantitativ art så användes även en blandning utav tematisk analys till det kvalitativa datat och en kvantitativ dataanalys för det resterande kvantitativa datat. Vi har även genomfört en utvärdering av en gamifierad plattform mot ett existerande ramverk. De genomförda litteraturstudierna är grunden för definitionerna av studiens centrala begrepp. Resultatet från denna studie bidrar med en berättigande till om en gamifierad plattform är något som studenterna skulle vilja se och använda. Baserat på studenternas inställning till en gamifierad plattform så har även en kravlista bearbetats fram. Något som framkom under denna studie är att studenterna inte motiveras utav en monetär belöning. Motiveringen kretsar istället kring möjligheten att verifiera kunskapen hos sig själv samt att ta vara på en möjlighet att visa vad man går för. / The purpose of this study is to find out what would motivate students to use a gamified platform to give each other formative feedback. The study is designed as a case study where the starting point of the study is the students' need for a possible common platform to facilitate each other's assistance in programming courses. But the study and subsequent results can also be applied to other courses. The use of both qualitative and quantitative data collection methods has been conducted, in the form of interviews and surveys as well as testing of a gamified platform. Since the collected data is of qualitative and quantitative nature, a mixture of thematic analysis to the qualitative data and a quantitative data analysis for the remaining quantitative data was also used. We have also evaluated a gamified platform against an existing framework. The literature studies are the basis for the definitions of the central concept of the study. The results of this study contribute to justifying whether a gamified platform is something that the students would like to see and use. Based on the students' attitude towards a gamified platform, a list of requirements has also been worked out. Something that has emerged from this study is that students are not motivated by a monetary reward. Instead, the motivation revolves around the ability to verify the knowledge for themselves and to take advantage of the opportunity to show off your skills.

Virtual Reality is a powerful tool for training, simulation, and computer aided design. The sensation of being in a real environment, while interacting with VR simulation is usually referred as sense of presence or sense of immersion. In most of the current applications the focus has been in providing a good visual and sound feedback to the user. However, the lack of mechanoreception/touch and proprioception/force feedback, or in other words, the impossibility of really touching the virtual objects makes the interaction unreal and more difficult. The rapid advances in VR and the development of techniques such as virtual medicine, virtual training and virtual prototyping have highlighted the lack of an effective input/feedback interface in these technologies and this led to research activity in all aspects of input and feedback technology related to touch/force sensation and reflection. This work presents the development of a generic integrated haptic (touch/force) feedback interface for use in VR and telepresence applications. The interface presented here consists of a 7 DOF input control/force feedback exoskeleton and a multi-functional input control/touch feedback glove interface. The arm exoskeleton monitors the motions of the human arm and feed back force sensations using ultra light weight pneumatic Muscle Actuators (pMA) to obtain high power weight outputs in a light comfortable and inherently safe structure. The glove interface monitors the motions of the hand and feed back touch sensations such as contact pressure, surface texture and temperature. These hardware systems have been integrated together and have been interfaced with a virtual reality system to permit exploration and testing of interactions with virtual environments. It is believed that the use of the system in VR, particularly, in all design and rapid prototyping applications will provide enhanced performance and will augment the design-production process.

An investigation is made into the approximate synthesis of optimal feedback controllers from the maximum principle necessary conditions. The overall synthesis can be separated into two phases: the computation of optimal open-loop controls (control programs) and trajectories from the necessary conditions, and the processing of this data to obtain an approximate representation of the optimal control as a state function. A particular technique for approximating the optimal feedback control from the optimal open-loop controls and trajectories is proposed and examined in Part I of the thesis. Parameters in a prechosen suboptimal controller structure are computed such that a sum of integral square deviations between the suboptimal and optimal feedback controls is minimized. The deviations are computed and summed over a certain set of trajectories which "cover" the system operating region. Experimentation with various controller structures is quite feasible since the controller parameters are computed by solving linear algebraic equations. Examples are given to illustrate the application of the technique and ways in which suitable controller structures may be found. If general purpose functions are to be used for this purpose, piecewise polynomial functions are recommended and techniques for their use are discussed. The synthesis method advocated is evaluated with respect to control sensitivity and instrumentation and compared to alternative procedures. Part II is concerned with the computation of optimal control programs, the most time consuming numerical task in the synthesis procedure. A new numerical optimization technique is presented which extends the function space Newton-Raphson method (quasilinearization) to a more general terminal condition. More significantly, a generalized Ricatti transformation is employed, and as a consequence, the integration of the unstable coupled canonical system is eliminated. Examples are given as evidence of the improved numerical qualities of the new algorithm. This method is one example of a class of algorithms, defined and developed in the thesis, called second variation methods. Some methods in this class have previously appeared in the literature but they are developed in the thesis from a unified point of view. The recognition of this class allows the relationships between the various methods to be seen more clearly as well as allowing techniques developed for use in one algorithm to be used in others. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Methods for studying the behaviour of on-off feedback systems, with the emphasis on steady-state periodic phenomena, are presented in this thesis. The two main problems analyzed are (1) the determination of the periods of self and forced oscillations in single-, double-, and multiloop systems containing an arbitrary number of on-off elements; and (2) the investigation of the asymptotic stability in the small of single-loop systems containing one on-off element which may or may not have a linear region of operation. To study the periodic phenomena in on-off systems, methods of determining the steady-state response of a single on-r-off element are first described. Concepts pertaining to the steady-state behaviour are then introduced: in this respect it has been found that generalizations of the concepts of the Hamel and Tsypkin loci and also of the phase characteristic of Neimark are useful in the study of self and forced oscillations. Both the Tsypkin loci and the phase characteristic concepts are used to determine the possible periods of self and forced oscillations in single- and double-loop systems containing an arbitrary number of on-off elements; these concepts are also applied to multiloop systems. On-off elements containing a linear region of operation, called a proportional band, are then described: both the transient and periodic response are presented. An approximate method for determining the periodic response is given. The concept of the Tsypkin loci is used to determine the possible periods of self and forced oscillations in a single-loop system containing one on-off element with a proportional band. The asymptotic stability in the small, or local stability, of the periodic states of single-loop systems containing one ideal on-off element has been considered by Tsypkin. In this thesis, Tsypkin's results have been generalized to include the cases of on-off elements containing a proportional band. The stability of such systems is determined by the stability of equivalent sampled-data systems with samplers having finite pulse widths. Finally, this stability problem is solved by a direct approach, one that makes use of the physical definition of local stability; the results obtained by this method agree with those derived by the sampled-data approach. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Clusters of galaxies provide a unique opportunity to simultaneously study cosmology through low scatter scaling relations and the complex baryonic physics that occurs in cluster cores. As such it is of key importance to quantify the effects of the various physical processes that drive cluster evolution. In this thesis a sample of 30 clusters from the Millennium Gas Simulation, of masses 10^14/h Solar Masses < M200 < 10^15/h Solar Masses, were selected and run at a higher resolution using the re-simulation technique, using a modified version of Gadget-2, an N-body SPH code. Each cluster was run multiple times with increasing levels of sub-grid physics in order to separate the different effects that govern cluster evolution. The models implemented starting with non-radiative (NR), simulations then added cooling and star formation (CSF), supernova feedback (SFB) and AGN feedback model (AGN) respectively. In order to best match observations a study of supernova and AGN feedback parameters was conducted. The sample of clusters were also used to quantify the magnitude of biases created when observing clusters, in an attempt to classify the accuracy of these measurements of clusters. Additionally, the effects of the biases were also included in the estimation of the cluster mass using hydrostatic equilibrium. The best match to the observed gas, star and baryon fractions, scaling relations and gas profiles was found when powerful supernova feedback was included, which heats gas particles to 10^7K, and an AGN model whose heating temperature scales with the final virial temperature of the cluster, so that particles in a 10^14/h Solar masses and 10^15/h Solar Masses cluster are heated to 10^8K and 10^8.5 K respectively. Outside the core, this model successfully matches all the observed profiles and scaling relations excluding the spectrascopic-like temperature. The core region is simulated with come success, with pressures matching those observed but gas that is too cool and dense, resulting in an inability to reproduce the non cool core entropy profiles. Cold dense gas is more heavily weighted in the spectrascopic-like temperature, allowing significant contributions from gas in substructures and cold dense clumps of gas that are un-ascociated with any substructures and seems to be an artificial construct of SPH. When this gas is removed using the method outlines in \cite{Roncarelli2006}, temperatures outside the core match observations, but the core region is still too dense and cool. Clearly this core region requires more complex physics, possibly through implementation of an improved SPH code or more complex sub-grid physics such as that associated with the AGN feedback. The bias profiles also exhibit a similar sensitivity to the cool dense gas clumps, having a profound effect on the observed profiles and creating significant scatter in the mass estimated using hydrostatic equilibrium. Removing this cold dense gas using the Roncarelli method results in reduced biases and hydrostatic mass estimates closer to the true values. The resulting scaling relations and profiles including the effects of biases differ from those without the biases, but not significantly. It is clear that biases can affect the observed profiles and scaling relations, but this effect is minimised by excluding the coldest densest gas. As the choice of how much gas is removed is somewhat arbitrary, it is clear that further work in this field would require better SPH implementations that do not produce the erroneous dense gas clumps and the generation of mock observations using the simulated data.

This thesis imparts the outcomes of a seven-week long quasi-experimental study that explored whether or not L2 learners who received intensive and highly focused indirect feedback on one type of treatable error - either the third person singular -s, plural endings -s, or definite article the - eventually become more accurate in the post-test as compared to a control group that did not. The paired-samples t-test comparing the pre-test and post-test scores of both groups demonstrates that the experimental group did no better than the control group after they received indirect corrective feedback. The independent samples t-test measuring the experimental and control group's accuracy shows no significant difference between the two groups. Effect sizes calculated, however, do indicate that, had the sample sizes been bigger, both groups would have eventually become more accurate in the errors targeted, although this would not have been because of the indirect feedback.