An important issue in the design and operation of assembly systems is the coordination of part deliveries and processing operations. These decisions can have a significant impact on inventory cost and customer service. The problem is especially complex when actual delivery and processing times are stochastic in nature, as is the case in small lot manufacturing. In this research a new methodology is developed for determining optimal part delivery dates in stochastic small lot assembly systems. This methodology is based on the descriptive model that comprises of taking the maximum of several random variables. The part arrival and processing times are assumed to follow various known probability distributions. The model includes consideration of limited buffers between stations. The overall objective is to minimize the expected total of part and subassembly inventory cost, makespan cost and tardiness cost. An approach based on the optimization of individual stations in isolation is used to obtain the part delivery dates at each station. Comparison of the approach with the nonlinear programming based approach to the problem indicates that it generates almost as good solutions in a fraction of the computation time. This approach is then used to study system behavior under various operating conditions. Results indicate that the Iognormal and gamma distributions result in higher total costs than the normal distribution. However, the normal distribution can be used to determine part delivery dates even if the actual distribution is Iognormal or gamma, with relatively small errors compared to the solutions obtained using the correct distribution. Variability is the most important factor in the design of the system, and affects the determination of due dates, buffer capacity requirements, choice of distribution, and estimates of system performance. The role of buffer capacities, however, is not very critical in the design of small lot unbalanced lines. / Ph. D.

The problem of determining cruise-dash trajectories is examined for the case of time-fuel optimization using a linear combination of time and fuel as the performance index. These trajectories consist of a transient arc followed by a steady-state arc. For cases where the steady-state arc is flown with full throttle the associated skeletal transient trajectories are also flown with full throttle, and approach the cruise-dash points monotonically in an asymptotic fashion. When the steady-state arc is flown at an intermediate throttle setting, the transient trajectories follow a singular control law and exhibit a complex structure that is different from the full-throttle transients. Singular transients in the vicinity of singular cruise-dash points are confined to a bounded singular surface. In state-space these trajectories trace out asymptotic spirals on the singular surface as they approach the steady-state arc. If the initial operating point lies outside the singular surface, then the transient trajectories are composites consisting of a full-throttle or zero-throttle segment flown until the singular surface is met, followed by a singular segment that fairs into the cruise-dash point. Addressing the question of optimality of the steady-state arc, it was found that although steady-state cruise fails a Jacobi-type condition, steady-state cruise-dash can satisfy this condition if the emphasis on time is sufficiently large. The outcome of the Jacobi-type test appears to be connected with the eigenstructure of the linearized state-adjoint system. / PH. D.

A mixed variational statement and corresponding finite element model are developed for an axisymmetric solid body under external symmetric loads using the updated Lagrangian formulation. The mixed finite element formulation treats the nodal displacements and stresses as the variables that can be approximated independently. The method of static condensation is used to keep some stresses across interfaces of a solid of revolution discontinuous. The stiffness matrix is transformed from semi-positive definite to positive definite. A rocket motor is composed of (1) case (2) propellant and (3) hollow air core and is modelled as an axisymmetric solid. The propellant of a rocket motor is treated as a viscoelastic material. Static and dynamic analyses are performed under (1) two opposite line loads (2) two opposite patch loads and (3) one line and one patch load combination. The modified Newton-Raphson method is used in the solutions of nonlinear algebraic equations. The analysis of free vibration is executed first and then the Newmark direct integration method is used in a transient analysis. Results of these analyses are compared with solutions obtained from different methods that are independent of the finite element method. / Ph. D.

This thesis discusses guidelines for developers of Augmented User Interfaces that can be used by illiterate and semi-literate users. To discover how illiterate and semi-literate users intuitively understand interaction with a computer, a series of Wizard of Oz experiments were conducted. In the first Wizard of Oz study, users were presented with a standard desktop computer, fitted with a number of input devices to determine how they assume interaction should occur. This study found that the users preferred the use of speech and gestures which mirrored findings from other researchers. The study also found that users struggled to understand the tab metaphor which is used frequently in applications. From these findings, a localised culturally-relevant tab interface was developed to determine the feasibility of localised Graphical User Interface components. A second study was undertaken to compare the localised tab interface with the traditional tabbed interface. This study collected both quantitative and qualitative data from the participants. It found that users could interact with a localised tabbed interface faster and more accurately than with the traditional counterparts. More importantly, users stated that they intuitively understood the localised interface component, whereas they did not understand the traditional tab metaphor. These user studies have shown that the use of self-explanatory animations, video feedback, localised tabbed interface metaphors and voice output have a positive impact on enabling illiterate and semi-literate users to access information. / TeX / Adobe Acrobat 9.51 Paper Capture Plug-in

Despite the inherent limitation of accessing information serially, voice applications are increasingly growing in popularity as computing technologies advance. This is a positive development, because voice communication offers a number of benefits over other forms of communication. For example, voice may be better for delivering services to users whose eyes and hands may be engaged in other activities (e.g. driving) or to semi-literate or illiterate users. This thesis proposes a knowledge based architecture for building voice applications to help reduce the limitations of serial access to information. The proposed architecture, called OVR (Ontologies, VoiceXML and Reasoners), uses a rich backend that represents knowledge via ontologies and utilises reasoning engines to reason with it, in order to generate intelligent behaviour. Ontologies were chosen over other knowledge representation formalisms because of their expressivity and executable format, and because current trends suggest a general shift towards the use of ontologies in many systems used for information storing and sharing. For the frontend, this architecture uses VoiceXML, the emerging, and de facto standard for voice automated applications. A functional prototype was built for an initial validation of the architecture. The system is a simple voice application to help locate information about service providers that offer HIV (Human Immunodeficiency Virus) testing. We called this implementation HTLS (HIV Testing Locator System). The functional prototype was implemented using a number of technologies. OWL API, a Java interface designed to facilitate manipulation of ontologies authored in OWL was used to build a customised query interface for HTLS. Pellet reasoner was used for supporting queries to the knowledge base and Drools (JBoss rule engine) was used for processing dialog rules. VXI was used as the VoiceXML browser and an experimental softswitch called iLanga as the bridge to the telephony system. (At the heart of iLanga is Asterisk, a well known PBX-in-a-box.) HTLS behaved properly under system testing, providing the sought initial validation of OVR. / LaTeX with hyperref package

The purpose of this dissertation is to examine the impact of domain and methodological tutorials on the attitude and performance of end-users who are neither well-versed in the domain area nor well-versed with an expert system which is designed to assist them in solving software selection tasks. With respect to these tasks and the mechanism for accomplishing them, the end-users can be categorized as "non-technical users." The design of this experiment was a 2 x 2 full factorial laboratory experiment employing eighty novice users as subjects. Each of the experimental subjects was randomly assigned to one of the four treatment groups corresponding to receipt or lack of receipt of tutorials concerning the problem domain and methodology employed by an expert system. The results of this research indicate that there is a significant interaction between receiving the application and expert system tutorial videos; better performance in terms of correct categorization of problems was observed in subjects who saw either both or neither video whereas worse performance was observed in subjects who saw only one video. In general, the video treatments were unrelated to a variety of attitude measures applied to the subjects. However, it was found that prior attitudes towards the use of computers were significantly related to the majority of the (posttest) attitude measures. Further, the general pattern was for attitudes towards computers to improve as a result of undergoing the experimental process with the viewing of the expert system video to be significant in the level of improvement.

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science in Engineering. / This dissertation shows that the engineering information system (EIS) is the primary integration mechanism in computer integrated manufacturing. The EIS has been defined by creating a functional as well as an information model. These models are the initial steps in the process of implementing an EIS by means of a database management system. The modelling of the EIS is defined within a work brealcdown structure for CIM acquisition which is applicable to any CIM project. The impact of the scope CIM of and the changes this requires are also defined. It is also shown that for an enterprise involved in the manufacture of complex systems it is more beneficial to introduce CIM in those areas outside the area of factory automation, The complexity of the EIS information model is such that it has not been possible to construct it manually. Automated tools should be used to create the EIS information model. / Andrew Chakane 2018

The paper investigates how Information Systems (IS) has emerged as the product of interdisciplinary discourses. The research aim in this study is to better understand diversity in IS research, and the extent to which the diversity of discourse expanded and contracted from 1995 to 2011. Methodologically, we apply a combined citations/co-citations analysis based on the eight Association for Information Systems (AIS) basket journals and the 22 subject-field classification framework provided by the Association of Business Schools (ABS). Our findings suggest that IS is in a state of continuous interaction and competition with other disciplines. General Management was reduced from a dominant position as a reference discipline in IS at the expense of a growing variety of other discourses including Business Strategy, Marketing, and Ethics and Governance among others. Over time, IS as a field moved from the periphery to a central position during its discursive formation. This supports the notion of IS as a fluid discipline dynamically embracing a diverse range of adjacent reference disciplines, whilst keeping a degree of continuing interaction with them. Understanding where IS is currently at allows us to better understand and propose fruitful avenues for its development in both academia and practice.

Innovation programmes require organisations to transfer both technology and knowledge to the diverse actors who operate within innovation eco-systems. The changing relationship between science and society has witnessed the growth of public private partnerships (PPP) to create new knowledge, while also triggering the emergence of a new role for universities as catalysts for innovation. This brings many challenges, stemming from the inherent nature of knowledge and the complex interactions involved with inter-disciplinary knowledge transfer. Concurrently, these public-funded programmes come under increasing scrutiny to demonstrate greater societal and economic impact as a return on research investment. Knowledge generated within the UK low carbon energy innovation system has the potential to facilitate the achievement of national emission targets. However, while knowledge may be successfully created, there is no guarantee that it will be disseminated and utilised in a way that contributes to the achievement of knowledge-related objectives. Current literature concentrates on the micro level inhibitors and enablers of knowledge transfer; however, a gap in empirical work which investigates system level knowledge interactions is evident. Research and practical application in this field has historically centred on technology transfer whilst under-emphasising the crucial role of knowledge within this complex, socio-technical innovation system. The overall aim of this qualitative study is to achieve a better understanding of the influences of knowledge transfer across a defined innovation system. This is achieved through the perceptions of participants via two case studies; one in a PPP and one in a University. Semi-structured interviews were conducted with twenty-eight participants, along with document analysis and participant observation at workshops, to investigate the participant perceptions. A three tier (macro-, meso- and micro-level) data analysis approach was adopted to reflect the systems level interactions. The study found that knowledge transfer is often perceived as the dissemination of information via explicit forms of knowledge, which may or may not be used by stakeholders to achieve innovation objectives. The main barriers to stakeholders utilising knowledge included: accessibility to knowledge; fit-for-purpose knowledge; stakeholder motivation/ability to use the knowledge; and viewing knowledge as an object. While there is an emerging impact agenda in academia, cultural and normative influences direct researchers towards traditional academic outputs (e.g. publications). Knowledge utilisation by stakeholders was found to be maximised through relational, stakeholder driven models, which view knowledge as a process. Knowledge utilisation was context specific, and, due to complex system influences, was never guaranteed to occur. Although planning for knowledge utilisation was undertaken at both the PPP and the University, implementing and measuring results was found to be difficult due to dynamic system influences such as understanding stakeholder motivations, resourcing constraints and complexity in the desired project outcomes. This makes adaptability and responsiveness important qualities for knowledge producers, while also necessitating specific skill sets. Based on this work, a set of principles were developed which should guide more effective utilisation of knowledge and promote more impactful research outcomes.

The study examined the effects of a technology-enhanced inquiry instructional model on students' understanding of science in Thailand. A mixed quantitative research design was selected for the research design. A pretest-posttest control-group design was implemented for the experimental research. A causal-comparative design using questionnaire and classroom observation was employed for the non-experimental research. Two sixth-grade classrooms at a medium-sized public school in Bangkok, Thailand were randomly selected for the study--one as the control group and the other as the experimental group. The 34 students in the control group only received the inquiry instructional model, while the 35 students in the experimental group received the technology-enhanced inquiry instructional model. Both groups of students had been taught by the same science teacher for 15 weeks (three periods per week). The results and findings from the study seemed to indicate that both the technology-enhanced inquiry instructional model and the inquiry instructional model significantly improve students' understanding of science. However, it might be claimed that students receiving the technology-enhanced inquiry instructional model gain more than students only receiving the inquiry instructional model. In addition, the technology-enhanced inquiry instructional model seemed to support the assessment during the 5E Model's evaluation stage. Most students appeared to have very good attitudes toward using it in the science classroom suggesting that the technology-enhanced inquiry instructional model motivates students to learn science. / text