Computer Science and Informatics

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Browsing Computer Science and Informatics by Author "De Wet, L."

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    Comparing brain-computer interfaces across varying technology access levels
    (University of the Free State, 2014) Dollman, Gavin John; De Wet, L.; Beelders, T. R.
    English: A brain-computer interface (BCI) is a device that uses neurophysiological signals measured from the brain to activate external machinery. BCIs have traditionally been used to enhance the standard of living for severely disabled patients. This has resulted in a shortage of data on how BCIs perform with able-bodied individuals. There has recently (2012) been a trend towards BCI research involving able users but these studies are still too few to make a substantial impact. Additionally, traditional input methods are being replaced or supplemented by alternative natural modes of interaction and these natural interactions have become known as NUIs. To investigate the suitability of a BCI as a NUI, this study used the Emotiv headset to provide direct measurement of a participant’s performance while performing tasks similar to wheelchair manipulation in order to determine whether a participant’s access to traditional input methods influences their performance. Thus, the main aim of this study was to investigate the usability of an Emotiv for robot navigation. Additionally, the study aimed to discover whether a user’s performance differed when using a keyboard compared to the Emotiv as well as investigating whether there was improvement of performance in the short term for a user through repetitive use of the Emotiv. In order to compare the usability of the Emotiv to a keyboard the participants were placed into groups based on their exposure to traditional input methods. This was verified based on their individual expertise rating, which was a measure of frequency and length of use. The test instrument used consisted of a written program that navigated a pair of Mindstorm NXT robots across a custom designed test course. Data was collected via usability testing which measured learnability, efficiency and effectiveness. Efficiency was measured as the time taken to complete a task while effectiveness was a measure of the errors made by a participant when completing a task. Results indicated that there was no significant difference between the groups’ efficiency and effectiveness when using the Emotiv to complete a task. Thus, a user’s previous experience with a traditional input method does not influence a user’s performance with an Emotiv when navigating a robot. This result indicates that the interface is intuitive to use and, therefore the Emotiv could be suitable as a NUI. The results for the usability metrics efficiency and effectiveness indicated that there was a significant difference between the performances with the Emotiv and a keyboard. The results show that, with the Emotiv, participants took more time to complete a task and made more errors when compared to a keyboard. This discrepancy was attributed to cognitive theory as it is believed that the participants violated their preformed schema which affected their performance. However, the participants quickly became comfortable with the Emotiv which supports the evidence that the interface is intuitive to use. For neither the usability metrics efficiency nor effectiveness was a significant improvement detected with repetitive use of the Emotiv. Thus, repetitive use of the Emotiv to navigate a robot does not improve a user’s performance over a short period of time. These results indicate that in terms of efficiency and effectiveness the keyboard is the superior interface. The results also revealed that a participant’s performance is not affected by their exposure to traditional input methods when utilising a BCI. Thus, the Emotiv is intuitive to use and appears suitable for use as a NUI. This study proved that the Emotiv is an intuitive interface and can be used with little to no previous experience.
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    Comparing the sensor glove and questionnaire as measures of computer anxiety
    (University of the Free State, 2014-01) Nkalai, Tlholohelo Stephania; De Wet, L.
    English: A vast amount of literature regarding computer anxiety exists. Consequently, a number of researchers have discovered different definitions for computer anxiety. Regardless of the numerous definitions, several researchers agree that computer anxiety involves emotional ‘fear’ or ‘apprehension’ when interacting or anticipating interaction with computers. Subsequently, some individuals who experience computer anxiety avoid using computers. This situation is undesirable because these days it is almost always a necessity for people to use computers in the workplace. It is therefore important to extensively investigate computer anxiety including measures which can be implemented to mitigate it. Different findings about computer anxiety regarding the correlates: gender, age, computer ownership, educational attainment and computer experience, exist. For example, while some research findings state that females experience higher levels of computer anxiety than males, other research findings assert that males experience computer anxiety more than the females. The contradictory findings regarding the correlates of computer anxiety could be attributed to the fact that most of the research studies which investigated computer anxiety relied solely on existing computer anxiety questionnaires. Using questionnaires exclusively poses various limitations which include relying on the ‘subjective’ responses of the participants. This research study incorporated another measurement of computer anxiety in addition to an existing computer anxiety questionnaire named Computer Anxiety Rating Scale. This additional measurement was performed using an instrument that measured physiological signals of a participant. The instrument is called an Emotion RECecognition system (EREC). It measures skin temperature and skin resistance and heart rate. Apart from the mentioned two, other data collection methods were used which are pre-test and post- test self-developed questionnaires, observations and interviews. With various measurements incorporated in this study, computer anxiety was investigated taking into consideration the following research questions:  To what extent does a sensor glove add value in measuring computer anxiety during usability testing when compared to anxiety questionnaires and observations?  To what extent is computer anxiety influenced by age, gender, computer experience, educational attainment, and ownership of a personal computer according to the anxiety questionnaire and the sensor glove? From the findings of the study in relation to the first research question, it can be concluded that the sensor glove does not add value. Instead, the sensor glove may add value when measuring stress. This means that although the EREC sensor glove measures skin conductance, changes in skin conductance may indicate changes in stress levels rather than anxiety levels. Regarding the second research question, it can be concluded that computer anxiety was not influenced by age, gender, computer experience, educational attainment, and ownership of a personal computer according to the anxiety questionnaire and the sensor glove.
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    Determining the usability, user experience, and continuance use of a mobile application and an online portal: A comparative case study
    (University of the Free State, 2023) Mhlongo, Thobani; De Wet, L.; Verkijika, S. F.
    Background: The increasing number of users with access to the internet, computers, and mobile devices propels most institutions to avail their services through online portals and mobile applications. However, these online portals and mobile applications depend on users utilising them. There are instances where users underutilise or completely opt out of these platforms. The reasons may include poor usability and negative user experience. This is a cause for concern since funds are invested in their development with the anticipated return on investment. Aim: This study aimed to compare the usability, user experience, and continuance use of a regulatory institution's mobile application and online portal with respect to performance, user satisfaction, and continuance intentions. Methodology: This single case study followed an explanatory sequential design, wherein the initial phase consisted of data collection using a self-administered questionnaire (quantitative phase). For the second phase, the data was collected using an interview protocol (qualitative phase). The self-administered questionnaire compared the usability, user experience, and continuance use of the mobile application and the online portal. The interview protocol was used to further explain the quantitative results. Participant recruitment used systematic random sampling for the quantitative phase and purposive sampling for the qualitative phase. The analytical approach involved descriptive and inferential statistics, and thematic analysis. Findings: The results established that the online portal was more usable than the mobile application; users had a positive user experience with the online portal and were more likely to use the online portal in future, but not so much with the mobile application. The contributing factors to the online portal findings were its efficiency, user-friendliness, understandability, and learnability. In addition, inefficiency, errors, limited functionality, and lack of user-friendliness issues were identified as contributors to the mobile application's negative experience and moderate usability. Regarding continuance use, the quantitative and qualitative results suggested that participants were keen to use the online portal in the future. However, the quantitative results for the mobile application indicated that the participants did not have interest in using the mobile application again in future, despite the interview results indicating otherwise. Participants identified improvement in efficiency and visual appeal as conditions for their future re-use of the mobile application.
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    The usability of natural user interfaces for gameplay
    (University of the Free State, 2015) Fouche, Rouxan Colin; Beelders, T. R.; De Wet, L.
    English: This study aimed to determine to what extent the usability of a two dimensional game was influenced by the use of a Natural User Interfaces (NUI) as opposed to a traditional keyboard and mouse combination. Two multimodal NUIs were investigated during the study. The first NUI combination (BCIG) made use of the Peregrine gaming glove for the activation of commands, combined with the Emotiv’s accelerometer for control of the cursor. The second NUI combination (BCIF) made use of facial expression recognition, offered by the Emotiv Brain Computer Interface (BCI), as a method of command activation in combination with the Emotiv’s built-in accelerometer for cursor control. A shooting genre game was developed and three tasks were included during development to simulate gaming actions. The first task used only stationary targets, the second task used predictable moving targets, whereas the third task made use of unpredictable moving targets. Since the Emotiv BCI allows for customisation of the accelerometer sensitivity settings, a pilot study was conducted to determine whether the low, medium or high sensitivity setting would provide the best cursor control. The low sensitivity resulted in the fastest gameplay overall as well as the least number of errors. It could thus be concluded that the lowest setting is the optimal setting since it provided the most efficient control for three out of the four metrics tested. After implementing this result, user testing, which involved 5 sessions per participant (n=18), was conducted. Data for three metrics was gathered during user testing, which included data on effectiveness, efficiency and learnability. Post-test questionnaires were administered to assess the level of user satisfaction with each NUI. The results of this study indicated that there is a difference between the usability of the traditional input combination, the keyboard and mouse, and the two NUIs investigated in this study. With regard to the effectiveness and efficiency metrics the traditional input combination was found to be the best, closely followed by BCIG. The three interfaces showed dissimilar levels of improvement, with the traditional keyboard and mouse combination showing the least, followed by BCIG, while the best improvement was noticed for BCIF. By analysing the subjective data gathered from post-test questionnaires, it was found that participants initially enjoyed using BCIG, and after several sessions their level of satisfaction improved. In comparison, the participants initially experienced a slightly negative feeling towards BCIF, which then improved over several sessions to a positive overall response. In conclusion, the keyboard and mouse combination provided far more effective and efficient input, with one exception being the fast command activation when making use of the Peregrine glove, where the two interfaces compared well. It was found that a significant obstacle in the way of NUIs is the existing skill and acceptance that computer users have with the traditional interface combination. Consequently, for individuals to accept and migrate to a more natural interface the new interface will have to provide more effective and efficient input than what is already achievable with the keyboard and mouse combination.