The rigorous quality criterion and intricate shapes of plastic injection molded parts require molders to improve process control systems in order to keep their competitive status in the market. In recent research, various advanced control algorithms are employed to develop in-line process controllers. In modem controllers design, in-mold process variables play a very important role in connecting machine variables and quality variables. Model-based predictive control (MPC) is used to investigate the controllability of cavity pressure and cavity temperature within a cycle or cycle-to-cycle. The objective of the present work is to demonstrate a procedure to develop MPC controllers based on simulation results. Moldflow® was used to simulate the injection molding process for a thin-wall cell phone cover. Cavity pressure profiles and part surface temperature profiles were extracted to develop the dynamic model for controller design. Thermal analysis for the cooling stage was investigated by ANSYS® FEM software. Mold surface temperature profiles were used for controller design. Dynamic matrix control, a type of MPC control, was developed by using Matlab® MPC Toolbox. A single-input/single-output MPC controller was developed to control cavity pressure in filling stage by manipulating injection flow rate. Simulation studies were then used to develop a MPC controller to implement a closed-loop control. The controller performed very well to control the pressure profile to trace the set-point, even with melt temperature or mold temperature change. Two MPC controllers were developed to control cavity surface cycle average temperature by manipulating coolant flow rate and coolant temperature. Both controllers show good controllability for cycle average temperature control. A two-input/two-output DMC controller was implemented to control cavity pressure and part surface temperature in the packing stage. Packing pressure and mold temperature were manipulated to trace the controlled profile set-points in each sampling time. Results shows that the controller was able to meet the set-point very well, for an unmeasured disturbance, based on a closed-loop test. All the controllers were developed based on simulation results, which will have some differences with real production data. Therefore, the model parameter and controller tuning parameter should be validated and modified if needed before real-time application. / Thesis / Master of Applied Science (MASc)

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Websites are a popular tool in our modern world, used daily by many companies and individuals. However, they are also rife with vulnerabilities, including SQL injection (SQLI) vulnerabilities. SQLI attacks can lead to significant damage to the data stored within web applications and their databases. Due to the dangers posed by these attacks, many countermeasures have been researched and implemented to protect websites against this threat. Various tools have been developed to enhance the process of detecting SQLI vulnerabilities and active SQLI attacks. Many of these tools have integrated machine learning technologies, aiming to improve their efficiency and effectiveness. Penetration testing is another valid method of detecting and fixing SQLI vulnerabilities, and there are tools designed to automate this process. Some of these automated exploitation tools have also incorporated machine learning techniques. This research aims to identify design requirements of a SQLI exploitation tool that utilizes Natural Language Generation for attack data. This research also aims to compare this new SQLI exploitation to existing tools. This research integrates various components from existing research projects to develop and evaluate the effectiveness of the proposed SQLI exploitation tool. This research establishes a framework for a SQL injection exploitation tool. Additionally, the study successfully tests multiple components of this new tool and compares the accuracy and speed of the new tool to already existing tools.

Published Article / The efficient design and manufacturing of injection moulds (and other tooling), requires collaboration between multi-disciplinary, geographically separated units and companies, including the company that orders plastic parts, the ones that design and/or produce the moulds and/or mould-components, and those that use injection moulding machines to produce components. Distributed collaborative tooling design and manufacturing, while being a great concept, is still difficult to implement in today's complex environment. This is clear as more functional groups become involved in the total product development process earlier to meet time-to-market and cost objectives. <br>Although internal design and manufacturing groups may have experience in collaborating with different degrees of success, the global trend is towards greater outsourcing of activities and inclusion of complementary organisations. The requirement for extended collaboration - the process of securely and selectively exchanging, reviewing, and managing the change of product information with other internal participants and external groups such as customers, design partners, suppliers and distributed manufacturing companies - presents huge challenges. <br>Delivering these capabilities in today's global product development processes requires a different approach to doing business than a few years ago. Companies must be willing to share more information, which "is hard because we are competitors." The toolmaking companies' in South Africa (of which 90% are small and medium size enterprises (SMEs)) concern for success in delivering these capabilities, can also be greatly impacted by the underlying software or information technology infrastructure required for supporting the entire product development process. <br>This article provides a perspective for SMEs and others that might participate in collaborative tool design and manufacture in South Africa today or in the future.

Published Article / This paper discusses the results obtained from studies on the performance of different cooling layouts. The conventional method of cooling makes use of straight-line cooling channels. This simple method of cooling does not possess the capability of uniformly cooling down the part produced. In contrast, conformal cooling is a technique that makes use of cooling channels in an injection moulding tool that closely follows the geometry of the part to be produced. The paper presents some experiences gained in a comparative case study of conventional cooling vs conformal cooling using simulation, followed by an experimental validation and statistical analysis of the results.

This thesis presents a multi-phase injection locking (IL) technique and its application in the locking range extension in multi-phase injection locking oscillators (ILOs) for Terahertz (THz) signal generation. The proposed technique can significantly increase the frequency locking range of a multi-phase injection locking oscillator compared to the conventional single-phase injection locking scheme. Based on the multi-phase IL technique and sub-harmonic ILOs, an “active frequency multiplier chain” architecture and a multi-ring system layout topology are also proposed to achieve scalable THz signal generation. As proof of concept, a cascaded 3-stage 3-phase 2nd-order sub-harmonic ILO chain is implemented in the IBM 9HP SiGe BiCMOS process. The design achieves a maximum output power of -16.6dBm at 498GHz, a phase noise of -87dBc/ Hz at 1MHz offset, and a total 5.1% frequency tuning range from 485.1GHz to 510.7GHz, which is the largest frequency tuning range among all the reported silicon-based THz oscillator sources in the 0.5THz band.

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