With the significant improvement in IoT technology and smart devices, data collection and distributed computation have led a foundation for Mobile crowd-sensing (MCS). MCS utilizes the capabilities of embedded sensors in smart devices for gathering data. MCS benefits both data provider (participant/user), and data requester, i.e. data providers via incentives/rewards, data requesters by delivering required data. Apart from the benefits gained through acquiring data, confronting challenges such as participant privacy, data trustworthiness, malicious attacks (from illegitimate users) need to be addressed to build robust and reliable data solicitation. In addition to that, it is necessary to consider user motivation and user preference, comfort during its engagement in crowd-sensing. User preferences/constraints can be due to privacy concerns in terms of location, the sensitivity of data or energy usage and many more. With this in mind, the main contributions of the thesis can be listed as follows. 1) We design user selective trustworthy data acquisition frameworks. We introduce a variety of user selection criteria to form participant communities based on participants reliability and income. To evaluate the trustworthiness of our selective reputation-based data acquisition, we consider malicious users in the environment and calculate the total rewards given to malicious users. Simulations results show that community formation based on the acquired income of participants ended up with a substantial loss to the cloud platform as well as participants. Contrary to that, reputation-based community formation has shown nearly equal platform utility (profit), negligible loss of user utility compared to benchmark Non-selective data acquisition with 7% malicious probability. 2) Moreover, we attempt to enable users to modify (allow/deny access to) their builtin sensor set according to their comfort levels. We formulate three comfort levels high (only allow access to sensors that would not directly reveal personal identity such as accelerometer, light sensor, etc.), moderate (obstruct access to sensitive data, e.g. camera), zero comfort (allow access to all users). We introduce Static modification, where users pre-arrange their sensor set before the start of data collection. Our feasibility study shows that pre-arrangement of the sensor set favours user comfort, user utility at the cost of loss in platform utility and performs better than selective reputation-based recruitment for the considered settings. 3) We apply Adaptive sensor modification on top of pre-arrangement of sensor set through which participants are authorized to re-arrange their sensor availability based on reliability scores. Simulation results show that the Adaptive comfort-aware approach performed better than static in terms of platform utility and achieved comparatively better user comfort with reasonable loss in user utility.

The goal of this thesis is to demonstrate how user testing can be used to identify and remediate learnability issues of a web application. Experimentation revolved around ASSISTments (www.assistments.org), an intelligent tutoring web application in which teachers create virtual classrooms where they can assign problem sets to their students and gain valuable data which can be used to make informed decisions. Recent log analysis uncovered very low task completion rates for new users on tasks that were intended to be trivial. Suspecting that this could be due to poor user interface design, user tests were conducted to help identify usability problems. Sessions were analyzed, and changes were made between each user test to address issues found. Feedback from user testing led to the implementation of an embedded support system. This support system consisted of a splash page which gave an overview of how the system should be used and a collection of context-sensitive tooltips which tried to give the user instructions on what to do as well as explain various parts of the interface. A randomized control trial was performed to measure the effectiveness of the embedded support. 69 participants were shown one of two interfaces: one with embedded support and one without. Task completion rates were analyzed for each of the groups. We found that the support system was able to influence which links a user clicked. However, although the support system was intended to address poor task completion rates, users in the conditions had similar task completion rates regardless of whether the support system was enabled.

For over two decades user-centric methods and techniques have been proposed to assist the production of usable, useful, and desirable software products. Despite these approaches, usability problems are still identified in finished software products creating problems at systems acceptance, rework and impacting end user experience. Part of the reason for these continuing problems is that user-centric approaches are not part of the traditional software engineering process. The literature review shows that software engineering and human-computer interaction are largely different communities. The aim of this thesis is to investigate whether the incorporation of user modelling and usability modelling into software requirements specifications would improve design quality and usability of software products. This research study used a Design Science dominant mixed research methodology consisting of case study and action research for creating, analysing and evaluating artefacts for improving the effectiveness of user-centred design and usability of software artefacts. Using the functional specification of an existing system in a government agency, ten designers created screen and interaction designs. The specification was then enhanced with usability specifications and the designers redeveloped their designs in the light of the enhanced specification. Both designs were subject to pre-defined usability tests and designers described their design experience as they worked. The results of the research demonstrated that enhancing traditional software requirements specifications with additional specifications of user modelling and usability modelling made a positive difference to both designer perception as well as design quality of user interface artefacts. The theoretical and practical values of these findings are explored.

Information retrieval (IR) is an important part of many tasks performed by people when they use computers. However, most IR research and theory isolates the IR component from the tasks performed by users. This is done by expressing user needs as a query performed on a database. In contrast this dissertation investigates the design and evaluation of information retrieval systems where the information retrieval mechanisms remain embedded in the user tasks. While there are a many different types of user tasks performed with computers we can specify common requirements for the IR needed in most tasks. There are both user interface and machine processing requirements. For user interfaces it is desirable if users interact directly with information databases, keep control of the interaction and are able to perform IR in a timely manner. Machine processing has to be within the capabilities of machines yet must fit with human perceptions and has to be efficient in both storage and computation. Given the overall requirements, the dissertation gives a particular implementation for how to embed IR in tasks. The implementation uses a vector representation for objects and organises the objects in a near neighbour data structure. Near neighbours are defined within the context of the tasks the users wish to achieve. While the implementation could use many different finding mechanisms, it emphasises a constructive solution building approach with localised browsing in the database. It is shown how the IR implementation fits with the overall task activities of the user. Much of the dissertation examines how to evaluate embedded IR. Embedded IR requires testing users' task performance in both real experiments and thought experiments. Implementation is tested by finding known objects, by validating the machine representations and their correspondence with human perceptions and by testing the machine performance of the implementation. Finally implications and extensions of the work arc explored by looking at the practicality of the approach, other methods of investigation and the possibility of building dynamic learning systems that improve with use.

This study explored how individuals categorized on handedness (being left or right hand dominant) reacted to having the vertical scroll bar of a web browser relocated to the left side of the screen. The relocation of the vertical scroll bar served as an alternative to the relocation of the prominent left aligned main navigation menu for most websites. Fifteen participants were recruited for the study. Each participant interacted with two versions of a web site in a modified browser to complete a set of ten short tasks. Participants completed tasks by interacting with a traditional and non-traditional vertical browser alignment. Left and right-handed participants were determined to be strikingly different in operation. Vertical scroll relocation produced some interesting results and responses.

Skeuomorphism är ett relativt nytt begrepp inom interaktionsdesign.Skeuomorphism är en designstil vars mål är att efterlikna realistiska objekt för attframkalla och skapa vissa effekter och upplevelser, som till exempel attunderförstått kommunicera en förståelse till användaren. Litteraturstudien visadepå att ingen har undersökt hur användare upplever inslagen och effekter somutlovas är spekulationer. Denna uppsats undersöker hur användare upplever inslagav skeuomorphism i digitala gränssnitt. Studien utfördes med hjälp av metodernathink-aloud och intervjuer för att besvara frågan, ”Hur upplever användare inslag avskeuomorphism i digitala grafiska gränssnitt?”. Studien resulterade i sex punktersom presenterar hur användare upplever inslag av skeuomorphism. / Skeuomorphism is a relatively new concept in interaction design. Skeuomorphism isa design style that aims to mimic realistic objects to develop and create certaineffects and experiences, such as implicitly communicate an understanding to theuser. The literature review showed that no one has studied how users experiencethese elements and the effects that are promised are only speculations. This essayexamines how users experience the elements of skeuomorphism in digitalinterfaces. The study was conducted using the methods think-aloud and interviewsto answer the question, “How do users experience elements of skeuomorphism indigital graphical interfaces?” . The study resulted in six aspects which presents howusers experience the elements of skeuomorphism.

The goal of this thesis was to explore the usability of on-foot sensors for ambulatory gait analysis. Using a human factors engineering approach, two different ambulatory gait analysis prototypes were assessed in two separate studies. The first study was conducted with student participants in a university setting and the second study was conducted in-situ with neurorehabilitation patients at Bridgepoint Hospital. The usability and patient experience of the prototypes were assessed, and based on these findings a set of recommendations was developed. These issues and recommendations are detailed in this thesis and are expected to inform the design of future iterations of the prototypes.

The goal of this thesis was to explore the usability of on-foot sensors for ambulatory gait analysis. Using a human factors engineering approach, two different ambulatory gait analysis prototypes were assessed in two separate studies. The first study was conducted with student participants in a university setting and the second study was conducted in-situ with neurorehabilitation patients at Bridgepoint Hospital. The usability and patient experience of the prototypes were assessed, and based on these findings a set of recommendations was developed. These issues and recommendations are detailed in this thesis and are expected to inform the design of future iterations of the prototypes.

Abstract INDIVIDUAL-TECHNOLOGY FIT: MATCHING INDIVIDUAL CHARACTERISTICS AND FEATURES OF BIOMETRIC INTERFACE TECHNOLOGIES WITH PERFORMANCE By ADRIANE B. RANDOLPH MAY 2007 Committee Chair: Dr. Melody Moore Jackson Major Department: Computer Information Systems The term biometric literally means “to measure the body”, and has recently been associated with physiological measures commonly used for personal verification and security applications. In this work, biometric describes physiological measures that may be used for non-muscularly controlled computer applications, such as brain-computer interfaces. Biometric interface technology is generally targeted for users with severe motor disabilities which may last long-term due to illness or injury or short-term due to temporary environmental conditions. Performance with a biometric interface can vary widely across users depending upon many factors ranging from health to experience. Unfortunately, there is no systematic method for pairing users with biometric interface technologies to achieve the best performance. The current methods to accommodate users through trial-and-error result in the loss of valuable time and resources as users sometimes have diminishing abilities or suffer from terminal illnesses. This dissertation presents a framework and methodology that links user characteristics and features of biometric interface technologies with performance, thus expediting the technology-fit process. The contributions include an outline of the underlying components of capturing and representing individual user characteristics and the impact on the performance of basic interaction tasks using a methodology called biometric user profiling. In addition, this work describes a methodology for objectively measuring an individual’s ability to control a specific biometric interface technology such as one based on measures of galvanic skin response or neural activity. Finally, this work incorporates these concepts into a new individual-technology fit framework for biometric interface technologies stemming from literature on task-technology fit. Key words: user profiles, biometric user profiling, biometric interfaces, fit, individual-technology fit, galvanic skin response, functional near-infrared, brain-computer interface

A common way of organizing Windows, Icons, Menus, and Pointers (WIMP) interfaces is to group tools into tool containers, providing one visual representation. Common tool containers include toolbars and menus, as well as more complex tool containers, like Microsoft Offices Ribbon, Toolglasses, and marking menus. The location of tool containers has been studied extensively in the past using Fittss Law, which governs selection time; however, selection time is only one aspect of user performance. In this thesis, I show that tool container location affects other aspects of user performance, specifically attention and awareness. The problem investigated in this thesis is that designers lack an understanding of the effects of tool container location on two important user performance factors: attention and group awareness. My solution is to provide an initial understanding of the effects of tool container location on these factors. In solving this problem, I developed a taxonomy of tool container location, and carried out two research studies. The two research studies investigated tool container location in two contexts: single-user performance with desktop interfaces, and group performance in tabletop interfaces. Through the two studies, I was able to show that tool container location does affect attention and group awareness, and to provide new recommendations for interface designers.