The value of establishing design requirements is well-argued and the need for their clear representation in the material used to brief designers is recognised. However, very little attention has been given as to how the design requirements should be represented for use by industrial designers and whether, or how, such representations benefit design. The research presented in the thesis aims to explore approaches to the organisation and presentation of design brief requirements for effective use by designers. We first examined how design requirements are specified, organised and represented in theory and practice. The role of design requirements in the design problem-solving process was analysed to gain insight into how explicit requirement representation might benefit the design process. An experimental study, using protocol analysis, was then conducted to investigate the impact of explicitly representing design requirements in achieving the theoretical benefits for such representations. The results indicate the explicit representation of design brief requirements yields systematic enhancements including increased utilisation of design requirements and the production of solutions assessed as meeting design requirements more successfully. Thus, the findings support the proposition that the manner in which design requirements are represented will impact upon the design process and the designers' performance. In line with the research findings, recommendations are made about how the organisation and presentation of requirements may be manipulated to achieve maximum positive enhancement and minimal negative reduction in the quality of the design process

Doctor of Philosophy (PhD) / Up till now, architects collaborating with other colleagues did so mostly face-to-face (FTF). They had to be in the same space (co-located) at the same time. Communi-cation was ‘spontaneous’ and ideas were represented, whether verbal or non-verbal, by talking and using ‘traditional drawing tools’. If they were geographically displaced, the interaction was then space affected as well as the probability of being time affected. In this case communication was usually mediated through the tele-phone, and graphically represented ideas were sent by Fax or posted documents. Recently, some architectural firms started using modems and Internet connections to exchange information, by transferring CAD drawings as well as design informa-tion, through e-mail and file transfer protocol (FTP). Discussing ideas in architecture, as a more abstract notion, is different from discuss-ing other more concrete arguments using video conferencing. It is more important to ‘see’ what is being discussed at hand than ‘watch’ the other person(s) involved in the discussion. In other words the data being conveyed might be of more impor-tance than the mode of communication. Taking into consideration recent developments in computer and communication technologies this thesis investigates different communication channels utilised in architectural collaboration through Computer Mediated Collaborative Design (CMCD) sessions as opposed to FTF sessions. This thesis investigates the possi-ble effects these different channels have on collaborative design in general and col-laborative design communication in particular. We argue that successful CMCD does not necessarily mean emulating close prox-imity environments. Excluding certain communication channels in a CMCD envi-ronment might affect the flow and quantity of synchronous collaborative communica-tion, but not necessarily the quality and content of mutually communicated and rep-resented design ideas. Therefore different communication channels might affect the type of communication and not necessarily the content of the communication. We propose that audio and video are not essential communication channels in CMCD environments. We posit that architects will collaborate and communicate design representations effectively although with some differences, since those two chan-nels might cause interruptions and successful collaborative sessions can take place without them. For this purpose we conducted twenty-four one-hour experiments involving final year architecture students all working to the same design brief. The experiments were divided into three categories, FTF, full computer mediated collaborative design sessions (CMCD-a; audio-video conferencing plus whiteboard as a shared drawing space) and limited computer mediated collaborative design sessions (CMCD-b; with Lambda MOO used as a chat medium plus whiteboard as a shared drawing space). The experiments were video and audio taped, transcribed and coded into a custom developed coding scheme. The results of the analysed coded data and observations of the videotapes provided evidence that there were noticeable differences between the three categories. There was more design communication and less communication control in the CMCD-b category compared to the FTF and CMCD-a categories. Verbal communi-cation became shorter and straight to the point in CMCD-b as opposed to spontane-ous non-stop chat in the other two categories. Moreover in CMCD-b the subjects were observed to be more reflective as well as choosing and re-examining their words to explain ideas to their partners. At times they were seen scrolling back through the text of the conversation in order to re-analyse or interpret the design ideas at hand. This was impossible in FTF and CMCD-a sessions, since the sub-jects were more spontaneous and audio representations were lost as soon as they were uttered. Also the video channel in the CMCD-a category was ignored and hardly used except for the first few minutes of the experiments, for a brief exchange of light humour on the appearance of each subject. The results obtained from analysing the experiments helped us conclude that differ-ent communication channels produce different collaborative environments. The three categories of communication for architectural collaboration explored in our ex-periments are indicative of the alternatives available to architects now. What is not clear to architects is why they would choose one category over another. We pro-pose that each category has its own strengths and difficulties for architectural col-laboration, and therefore should be selected on the basis of the type of communica-tion considered to be most effective for the stage and tasks of the design project.

Doctor of Philosophy (PhD) / Up till now, architects collaborating with other colleagues did so mostly face-to-face (FTF). They had to be in the same space (co-located) at the same time. Communi-cation was ‘spontaneous’ and ideas were represented, whether verbal or non-verbal, by talking and using ‘traditional drawing tools’. If they were geographically displaced, the interaction was then space affected as well as the probability of being time affected. In this case communication was usually mediated through the tele-phone, and graphically represented ideas were sent by Fax or posted documents. Recently, some architectural firms started using modems and Internet connections to exchange information, by transferring CAD drawings as well as design informa-tion, through e-mail and file transfer protocol (FTP). Discussing ideas in architecture, as a more abstract notion, is different from discuss-ing other more concrete arguments using video conferencing. It is more important to ‘see’ what is being discussed at hand than ‘watch’ the other person(s) involved in the discussion. In other words the data being conveyed might be of more impor-tance than the mode of communication. Taking into consideration recent developments in computer and communication technologies this thesis investigates different communication channels utilised in architectural collaboration through Computer Mediated Collaborative Design (CMCD) sessions as opposed to FTF sessions. This thesis investigates the possi-ble effects these different channels have on collaborative design in general and col-laborative design communication in particular. We argue that successful CMCD does not necessarily mean emulating close prox-imity environments. Excluding certain communication channels in a CMCD envi-ronment might affect the flow and quantity of synchronous collaborative communica-tion, but not necessarily the quality and content of mutually communicated and rep-resented design ideas. Therefore different communication channels might affect the type of communication and not necessarily the content of the communication. We propose that audio and video are not essential communication channels in CMCD environments. We posit that architects will collaborate and communicate design representations effectively although with some differences, since those two chan-nels might cause interruptions and successful collaborative sessions can take place without them. For this purpose we conducted twenty-four one-hour experiments involving final year architecture students all working to the same design brief. The experiments were divided into three categories, FTF, full computer mediated collaborative design sessions (CMCD-a; audio-video conferencing plus whiteboard as a shared drawing space) and limited computer mediated collaborative design sessions (CMCD-b; with Lambda MOO used as a chat medium plus whiteboard as a shared drawing space). The experiments were video and audio taped, transcribed and coded into a custom developed coding scheme. The results of the analysed coded data and observations of the videotapes provided evidence that there were noticeable differences between the three categories. There was more design communication and less communication control in the CMCD-b category compared to the FTF and CMCD-a categories. Verbal communi-cation became shorter and straight to the point in CMCD-b as opposed to spontane-ous non-stop chat in the other two categories. Moreover in CMCD-b the subjects were observed to be more reflective as well as choosing and re-examining their words to explain ideas to their partners. At times they were seen scrolling back through the text of the conversation in order to re-analyse or interpret the design ideas at hand. This was impossible in FTF and CMCD-a sessions, since the sub-jects were more spontaneous and audio representations were lost as soon as they were uttered. Also the video channel in the CMCD-a category was ignored and hardly used except for the first few minutes of the experiments, for a brief exchange of light humour on the appearance of each subject. The results obtained from analysing the experiments helped us conclude that differ-ent communication channels produce different collaborative environments. The three categories of communication for architectural collaboration explored in our ex-periments are indicative of the alternatives available to architects now. What is not clear to architects is why they would choose one category over another. We pro-pose that each category has its own strengths and difficulties for architectural col-laboration, and therefore should be selected on the basis of the type of communica-tion considered to be most effective for the stage and tasks of the design project.

Security protocols are important and widely used because they enable secure communication to take place over insecure networks. Over the years numerous formal methods have been developed to assist protocol designers by analysing models of these protocols to determine their security properties. Beyond the design stage however, developers rarely employ formal methods when implementing security protocols. This may result in implementation flaws often leading to security breaches. This dissertation contributes to the study of security protocol analysis by advancing the emerging field of implementation analysis. Two tools are presented which together translate between Java and the LySa process calculus. Elyjah translates Java implementations into formal models in LySa. In contrast, Hajyle generates Java implementations from LySa models. These tools and the accompanying LySa verification tool perform rapid static analysis and have been integrated into the Eclipse Development Environment. The speed of the static analysis allows these tools to be used at compile-time without disrupting a developer’s workflow. This allows us to position this work in the domain of practical software tools supporting working developers. As many of these developers may be unfamiliar with modelling security protocols a suite of tools for the LySa process calculus is also provided. These tools are designed to make LySa models easier to understand and manipulate. Additional tools are provided for performance modelling of security protocols. These allow both the designer and the implementor to predict and analyse the overall time taken for a protocol run to complete. Elyjah was among the very first tools to provide a method of translating between implementation and formal model, and the first to use either Java for the implementation language or LySa for the modelling language. To the best of our knowledge, the combination of Elyjah and Hajyle represents the first and so far only system which provides translation from both code to model and back again.

PhD / In design literature, how designers think and how they design have been identified as a reflection of how they interact with their sketches. Sketching in architectural design is still a central concern which shapes our understanding of the design process and the development of new tools. Sketching not only serves as a visual aid to store and retrieve conceptualisations, but as a medium to facilitate more ideas, and to revise and refine these ideas. This thesis examined how mental imagery and sketching is used in designing by conducting a protocol analysis study with six expert architects. Each architect was required to think aloud and design under two different conditions: one in which s/he had access to sketching and one in which s/he was blindfolded (s/he did not have access to sketching). At the end of the blindfold condition the architects were required to quickly sketch what they held in their minds. The architects were able to come up with satisfying design solutions and some reported that using their imagery could be another way of designing. The resulting sketches were assessed by judges and were found to have no significant differences in overall quality. Expert architects were able to construct and maintain the design of a building without having access to sketching. The analysis of the blindfold and sketching design protocols did not demonstrate any differences in the quantity of cognitive actions in perceptual, conceptual, functional and evaluative categories. Each architect’s cognitive structure and designing behaviour in the blindfold activity mimicked her/his cognitive structure and designing behaviour in the sketching activity. The analysis of links between the design ideas demonstrated that architects’ performance in idea development was higher under the blindfold condition, compared to their sketching condition. It was also found that architects’ blindfold design performance was improved when they were more familiar with the site layout. These results imply that expert designers may not need sketching as a medium for their reflective conversation with the situation. This study indicates that constructing internal representations can be a strong tool for designing. Future studies may show that designers may not need sketching for the generation of certain designs during the early phases of conceptual designing.

Many destinations throughout the world have developed events portfolios as a strategic initiative to attract tourists and their associated economic benefits. The ability of events to attract people to a destination for the purpose of attending the event is well documented. However the ability of an event to add value to attract tourists before or after the event is not so clear. In other words, can an events portfolio positively influence the decision to visit a destination at a time when none of the promoted events are scheduled? As a first step towards answering this important question, this study explores the contribution of an events portfolio to a consumer’s perceptions of a destination and how this influences their decision to attend a destination under these circumstances. The proposed study conducts a protocol analysis based on consumer’s decision-making thoughts. Each participant was given a choice between two destinations in India. Participants were asked to ‘think out loud’ as they made the decision to visit one of two possible destinations, one with an events portfolio and the other without. However, their visit does not coincide with the events’ dates. The results suggest four lines of reasoning utilised by prospective tourists in the destination choice process: 1) destination image; 2) the timing of the event with respect the time of visit; 3) tourists’ level of interest in the event; and, 4) events not listed in the events portfolio might be scheduled during the time of the proposed visit. In course of finding lines of reasoning for cross-cultural issues it was found that culture, architecture, English language usage, and food are the major aspects that tourists consider while travelling to Indian destinations. In terms of the events portfolio, there is evidence of a preference for a ‘fit’ between the event and Indian culture.

Many destinations throughout the world have developed events portfolios as a strategic initiative to attract tourists and their associated economic benefits. The ability of events to attract people to a destination for the purpose of attending the event is well documented. However the ability of an event to add value to attract tourists before or after the event is not so clear. In other words, can an events portfolio positively influence the decision to visit a destination at a time when none of the promoted events are scheduled? As a first step towards answering this important question, this study explores the contribution of an events portfolio to a consumer’s perceptions of a destination and how this influences their decision to attend a destination under these circumstances. The proposed study conducts a protocol analysis based on consumer’s decision-making thoughts. Each participant was given a choice between two destinations in India. Participants were asked to ‘think out loud’ as they made the decision to visit one of two possible destinations, one with an events portfolio and the other without. However, their visit does not coincide with the events’ dates. The results suggest four lines of reasoning utilised by prospective tourists in the destination choice process: 1) destination image; 2) the timing of the event with respect the time of visit; 3) tourists’ level of interest in the event; and, 4) events not listed in the events portfolio might be scheduled during the time of the proposed visit. In course of finding lines of reasoning for cross-cultural issues it was found that culture, architecture, English language usage, and food are the major aspects that tourists consider while travelling to Indian destinations. In terms of the events portfolio, there is evidence of a preference for a ‘fit’ between the event and Indian culture.

PhD / In design literature, how designers think and how they design have been identified as a reflection of how they interact with their sketches. Sketching in architectural design is still a central concern which shapes our understanding of the design process and the development of new tools. Sketching not only serves as a visual aid to store and retrieve conceptualisations, but as a medium to facilitate more ideas, and to revise and refine these ideas. This thesis examined how mental imagery and sketching is used in designing by conducting a protocol analysis study with six expert architects. Each architect was required to think aloud and design under two different conditions: one in which s/he had access to sketching and one in which s/he was blindfolded (s/he did not have access to sketching). At the end of the blindfold condition the architects were required to quickly sketch what they held in their minds. The architects were able to come up with satisfying design solutions and some reported that using their imagery could be another way of designing. The resulting sketches were assessed by judges and were found to have no significant differences in overall quality. Expert architects were able to construct and maintain the design of a building without having access to sketching. The analysis of the blindfold and sketching design protocols did not demonstrate any differences in the quantity of cognitive actions in perceptual, conceptual, functional and evaluative categories. Each architect’s cognitive structure and designing behaviour in the blindfold activity mimicked her/his cognitive structure and designing behaviour in the sketching activity. The analysis of links between the design ideas demonstrated that architects’ performance in idea development was higher under the blindfold condition, compared to their sketching condition. It was also found that architects’ blindfold design performance was improved when they were more familiar with the site layout. These results imply that expert designers may not need sketching as a medium for their reflective conversation with the situation. This study indicates that constructing internal representations can be a strong tool for designing. Future studies may show that designers may not need sketching for the generation of certain designs during the early phases of conceptual designing.

Operating System fingerprinting is a reconnaissance method used by Whitehats and Blackhats alike. Current techniques for fingerprinting do not take into account tunneling protocols, such as IPSec, SSL/TLS, and SSH, which effectively `wrap` network traffic in a ciphertext mantle, thus potentially rendering passive monitoring ineffectual. Whether encryption makes VPN tunnel endpoints immune to fingerprinting, or yields the encrypted contents of the VPN tunnel entirely indistinguishable, is a topic that has received modest coverage in academic literature. This study addresses these question by targeting two tunnelling protocols: IPSec and SSL/TLS. A new fingerprinting methodology is presented, several fingerprinting discriminants are identified, and test results are set forth, showing that endpoint identities can be uncovered, and that some of the contents of encrypted VPN tunnels can in fact be discerned. / Dissertation (MSc (Computer Science))--University of Pretoria, 2005. / Computer Science / unrestricted

This thesis analyses the use of value models as boundary objects to support decision making during conceptual design of Product-Service Systems. Compared to requirements-based models, value models are claimed to enhance understanding of the design problems and customer needs, as well as to help the design team in creating more value adding solutions. The work of this thesis was to prepare, conduct and analyse a series of design experiments, which are are based on the continuous observations of designers’ verbalized design considerations. Protocol analysis was conducted to investigate how value models perform as boundary objects in design, in comparison with requirements-based models. The time spent on each different activity in the protocol has been used as main proxy in the experiment. Data triangulation was ensured by the use of a questionnaire that was answered by all participants. Both methods revealed that in the preliminary phase, value models are more effective than requirements-based models in conveying intuitive value-related information, assessing intangibles value aspects, and encouraging discussions on value concerns.