Static authentication, where user identity is checked once at login time, can be circumvented no matter how strong the authentication mechanism is. Through attacks such as man-in-the-middle and its variants, an authenticated session can be hijacked later after the initial login process has been completed. In the last decade, continuous authentication (CA) using biometrics has emerged as a possible remedy against session hijacking. CA consists of testing the authenticity of the user repeatedly throughout the authenticated session as data becomes available. CA is expected to be carried out unobtrusively, due to its repetitive nature, which means that the authentication information must be collectible without any active involvement of the user and without using any special purpose hardware devices (e.g. biometric readers). Stylometry analysis, which consists of checking whether a target document was written or not by a specific individual, could potentially be used for CA. Although stylometric techniques can achieve high accuracy rates for long documents, it is still challenging to identify an author for short documents, in particular when dealing with large author populations. In this dissertation, we propose a new framework for continuous authentication using authorship verification based on the writing style. Authorship verification can be checked using stylometric techniques through the analysis of linguistic styles and writing characteristics of the authors. Different from traditional authorship verification that focuses on long texts, we tackle the use of short messages. Shorter authentication delay (i.e. smaller data sample) is essential to reduce the window size of the re-authentication period in CA. We validate our method using different block sizes, including 140, 280, and 500 characters, and investigate shallow and deep learning architectures for machine learning classification. Experimental evaluation of the proposed authorship verification approach based on the Enron emails dataset with 76 authors yields an Equal Error Rate (EER) of 8.21% and Twitter dataset with 100 authors yields an EER of 10.08%. The evaluation of the approach using relatively smaller forgery samples with 10 authors yields an EER of 5.48%. / Graduate

Submitted in fulfilment of the requirements of the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2001. / Kluyveromyces sp. have adapted to existence in milk due to the evolution of permeabilisation and hydrolytic systems that allow the utilisation of lactose, the sugar most abundant in milk. Lactose hydrolysis, to equimolar units of glucose and galactose, is facilitated by a glycoside hydrolase, i.e., β-galactosidase (EC 3.2.1.23). The versatility of this enzyme allows its application in numerous industrial processes, amongst the most significant of which, is its role in the alleviation of lactose intolerance, one of the most prevalent digestive ailments, globally. In this study, β-galactosidase production by Kluyveromyces lactis UOFS y-0939 was initially optimised in shake flask culture with lactose as the sole carbon source, and thereafter, production was scaled up to batch, fedbatch and continuous culture. Shake flask studies revealed optimum conditions of 30°C, pH 7 and a 10% inoculum ratio, to be most favourable for β-galactosidase synthesis, producing a maximum of 0.35 ± 0.05 U.ml-1 when cell lysates were prepared by ultrasonication with glass beads. Batch cultivation in 28.2 and 40 g.L-1 lactose revealed that elevated levels of the carbon source was not inhibitory to β-galactosidase production, as maximum enzyme activities of 1.58 and 4.08 U.ml-1, respectively, were achieved. Cell lysates prepared by ultrasonication and homogenisation were compared and homogenised cell lysates were more than 3.5 fold higher that those prepared by ultrasonication, proving homogenisation to be the superior method for cell disruption. The lactose feed rate of 4 g.L-1.h-1 in fed-batch culture operated at ± 20.4% DO, appeared to be inhibitory to biomass production, as indicated by the lower biomass productivity in fed-batch (0.82 g.L-1.h-1) than batch culture (1.27 g.L-1.h-1). Enzyme titres, however, were favoured by the low DO levels as a maximum of 8.7 U.ml-1, 5.5 fold more than that obtained in batch culture, was achieved, and would be expected to increase proportionally with the biomass. Continuous culture operated at a dilution rate of 0.2 h-1, under strictly aerobic conditions, revealed these conditions to be inhibitory to the lactose consumption rate, however, the non-limiting lactose and high DO environment was favourable for β-galactosidase synthesis, achieving an average of 8 ± 0.9 U.ml-1 in steady state.

Submitted in fulfillment of the requirements for the Master of Technology Degree in Business Administration, Durban University of Technology, 2014. / The UoTs are operating in an environment in which they have to deal with multifarious and complex challenges. Responding effectively to such challenges has become critical for UoTs in achieving a competitive advantage and in outsmarting competitors. Traditional approaches which deal with rapid changes in the higher education landscape have become obsolete. The fact is that UoTs are faced with transformational challenges - increasing student intake, the need for improving throughput rate, the need for remaining financially sustainable while producing the top graduates required by industry. Given this background, this study investigates the application of a learning organisation philosophy for improving processes and practices in the UoTs of KwaZulu-Natal. Learning organisation philosophy has been identified as one of the best approaches for organisations in the corporate sector. It is used to achieve and sustain a competitive advantage. Learning organisation philosophy encourages the culture of continuous learning by members of the organisation, so as to achieve strategic objectives. This study provides UoTs’ perspectives of the learning organisation theory. Data was collected from employees of DUT. The sample was drawn from both administrative and academic employees. A self-administered questionnaire was used in collecting the data. The findings of this study reveal that the application of a learning organisation philosophy will help UoTs improve their processes and practices. Based on the findings, the majority of participants indicated that they would embrace and support the application of a learning organisation philosophy at DUT. It has to be noted that in the study, DUT was used as a case study.

This paper considers four approaches to ordinal predictors in linear regression to evaluate how these contrast with respect to predictive accuracy. The two most typical treatments, namely, dummy coding and classic linear regression on assigned level scores are compared with two improved methods; penalized smoothed coefficients and a generalized additive model with cubic splines. A simulation study is conducted to assess all on the basis of predictive performance. Our results show that the dummy based methods surpass the numeric at low sample sizes. Although, as sample size increases, differences between the methods diminish. Tendencies of overfitting are identified among the dummy methods. We conclude by stating that the choice of method not only ought to be context driven, but done in the light of all characteristics.

Working Lean, i.e. “eliminating non-value activities from work processes by applying a robust set of performance change tools and emphasizing excellence in operations to deliver superior customer service,” has received significant attention and become a concept of interest for businesses, especially during recent years. Fundamentally, the concept of Lean is built on the aims of waste reduction and value creation with keywords such as continuous improvement, quality, and efficiency guiding the process. Lean was originally developed with production in mind, but many in the field argue that its applicability reaches further and holds potential within other contexts, such as service, as well. The purpose of this study is to derive lessons learned from individuals working in the service sector regarding whether or not Lean is applicable in the context of service and to explore what factors and challenges are perceived to influence the likeliness of success. An abductive approach has been pursued by the use of semistructured interviews with employees from different levels within organizations in the Swedish service sector. In addition, an external perspective by interviewing a Lean consultant has been of interest. The data gained has been analysed to identify patterns which have then been searched for in existing literature. The findings provide evidence that Lean is applicable in service. Furthermore, success factors related to the following core categories; employee engagement and competence, having a philosophical approach, leadership, management, implementation, organizational and national culture, and management of variation were identified. Lastly, a misconception of Lean, employee resistance and suboptimization were three challenges found.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / It is widely recognized that telemetry channels, particularly airborne channels, are afflicted by multipath propagation effects. It has also been shown that adaptive equalization can be highly effective in mitigating these effects. However, numerous other factors influence the behavior of adaptive equalization, and the type of modulation employed is certainly one of these factors. This is particularly true on modulations which exhibit different operating bandwidths. In this paper, we will examine the effect multipath and adaptive equalization for three modulation techniques which are either already in use, or have been proposed, for airborne telemetry.

ENGLISH ABSTRACT: Many organisations are perusing a process improvement programme in order to gain competitive advantage through improved product and service quality, operational efficiencies and customer experience. Whilst Six Sigma adopts a project-oriented, expert-led approach to improving processes, Total Quality Management (TQM), Lean and Operational Excellence (OE) programmes typically promote a culture of Continuous Improvement (CI) where lower-level employees are encouraged and empowered to evaluate and optimise their own working practices and processes. In order to make CI successful and sustainable in an organisation, employees need to have a positive attitude towards CI. Whilst previous research had already established the relationship between CI, Organisational Learning (OL) and company performance, this research set out to establish if any of the five disciplines of the Senge (1994) Learning Organisation (LO) influenced on an employee’s (positive) attitude towards CI. In keeping with the Dimensions of the Learning Organisation Questionnaire (DLOQ), the five disciplines of the LO were structured within individual, team and organisational factors. Through a structured survey and statistical correlation analysis, this research has shown that, whilst the team and organisational factors did not influence on an employee’s attitude to CI, personal mastery does have an influence on an employee’s attitude towards CI. It is therefore recommended that an organisation that wishes to create a culture of CI also actively works to improve the personal mastery of those employees who are expected to be involved in CI.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper describes the development and test results of a Frequency Modulated Continuous Wave (FMCW) L-Band radar testbed designed to detect obstacles in the proximity of an Unmanned Aerial Vehicle (UAV). From laboratory loopback tests, it was calculated that with pulse compression and a transmit power of 150 mW (22 dBm), the radar is capable of detecting an object with a 0.014-m2 radar cross-sectional area at ranges between 500 ft to 1 mi. Analysis shows that post processing of the collected data would reveal information about the obstacle such as its range and location relative to the aircraft. Design and testing procedures are discussed.

published_or_final_version / Anatomy / Master / Master of Philosophy

Dimensional Analysis is a technique that has allowed engineering evaluation of complex objects by scaling analysis results of representative simpler models. The original premise of the procedure stems from the idea of developing non-dimensional parameters to relate physical events and underlying analytical basis. Extending the process to incorporate non-linear and time variant behavior has led to development of a novel process of similitude called the Empirical Similitude Method (ESM) where experimental data of test specimen is combined to produce the required prediction values. Using the original motivation and hypothesis of ESM, this research has expanded the experimental similitude process by using adapted matrix representations and continuous functional mapping of test results. This new approach has provided more rigorous mathematical definitions for similarity and prediction estimations based on an innovative error minimization algorithm. Shape factors are also introduced and integrated into ESM to obtain comprehensive evaluation of specimen choices. A detailed overview is provided summarizing methods, principles and laws of traditional similitude (TSM) and systems that satisfy extension into ESM. Applicability of ESM in different systems is described based on the limitations of TSM in the evaluation of complex structures. Several examples and ideas spanning aerodynamic, thermal, mechanical and electro-magnetic domains are illustrated to complement inherent technical analysis. For example, the new ESM procedure is shown to be considerably more accurate than earlier methods in predicting the values of drag coefficient of an airfoil. A final foray into the regime of \design evaluation by similarity" is made to elucidate applicability and efficiency of developed techniques in practical systems and products. A thorough methodology is also presented highlighting pertinent procedures and processes in usage of this method. / text