The emergence of Vehicular Ad-hoc Networks (VANETs) in the past decade has added a level of complexity to the modelling of Intelligent Transportation System (ITS) applications. In this paper, the Vehicular Network Integrated Simulator (VNetIntSim) is introduced as a new transportation network and VANET simulation tool by integrating transportation and VANET modelling. Specifically, it integrates the OPNET software, a communication network simulator, and the INTEGRATION software, a microscopic traffic simulation software. The INTEGRATION software simulates the movement of travellers and vehicles, while the OPNET software models the data exchange through the communication system. Information is exchanged between the two simulators as needed. The paper describes the implementation and the operation details of the VNetIntSim as well as the features it supports such as multiclass support and vehicle reuse. Subsequently, VNetIntSim is used to quantify the impact of mobility parameters (vehicular traffic stream speed and density) on the communication system performance considering Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) applications. Specifically, the routing performance (packet drops and route discovery time), IP processing delay in case of a file transfer protocol (FTP) application, and jitter in case of a Voice over Internet Protocol (VoIP) application and evaluated.

<p> A study of gradient optimization techniques, in particular as applied to system modelling problems, is made. Three efficient techniques are used to derive optimum second-order and third-order models for a seventh-order system. The optimization techniques are the Fletcher-Powell method, a more recent method proposed by Fletcher and a method based on a more general objective function proposed by Jacobson and Oksman.</p> <p> The approximation is carried out in the time domain. Least squares and least pth criteria are used, and almost minimax results are obtained for large values of p. Values of p up to 10^12 are successfully used. The results are compared with other minimax type algorithms.</p> / Thesis / Master of Engineering (MEngr)

Published Article / This study investigates the use of off-grid micro-hydrokinetic river system as a cost-effective and sustainable electricity supply option for remote rural residents in close proximity to flowing water and not having access to grid electricity. This hydrokinetic technology is still in the development stage and there is a lack of application especially in rural areas with reasonable water resource. This study will present the economic and environmental benefits of the proposed system. A mathematical model is developed to simulate the system performance as submitted to different solicitations. A test prototype will also be used in order to validate the simulation results.

Convective snow bands develop commonly over the open water surface of lakes or seas when cold airgets advected from a continent. Enhanced heat and moisture fluxes from the comparatively warm waterbody trigger shallow convection and an unstable boundary layer builds up. Relatively strong wind canorganize this convection into wind-parallel quasi-stationary cloud bands with moving individual cells.Depending on various factors like the horizontal wind, the vertical shear or the shape of the coast, thosecloud bands can form of different strength and structure. When the air mass meets the coast orographicforcing causes horizontal convergence and vertical lifting intensifies the precipitation at the coast. If thewind direction stays constant for several days a single snow band would accumulate its precipitation ina very restricted region and cause locally a significant increase in snow depth. This process leads in thecold season repeatedly to severe precipitation events at the Swedish east coast. Large amounts of snowalong with strong wind speeds can cause serious problems for traffic and infrastructure.Two different cases of convective snow bands in the Baltic Sea area were selected to simulate theassociated atmospheric conditions with a total of five different model systems. The atmosphere climatemodel RCA has been used independently at default settings as well as with increased resolution on avertical and a horizontal scale and furthermore coupled either to the ice-ocean model NEMO or the wavemodel component WAM.Comparing all models the crucial parameters like wind, temperature, heat fluxes, and precipitationvary generally in a reasonable range. However, the model systems show systematical differences amongthemselves. The strongest 10 meter wind speeds can be observed for both RCA models with increasedresolution. The RCA-WAM simulation shows its wind enhancement during the snow band event witha time shift to the other models by several hours. The mean directional wind shear above the Gulf ofBothnia, the snow band’s region of origin, is for all models small. The warmest sea surface temperaturesare reached by the RCA-NEMO simulation, which as a result also stands out for its most intense heatfluxes in both sensible and latent heat. Both high resolution RCA models as well as RCA-NEMO givethe most remarkable local precipitation rates. The original RCA and RCA-WAM simulate significantlyless snowfall. Local comparison with SMHI station measurements show that the models represent thetrend of wind, temperature and precipitation evolution well. However, all models decelerate the air masstoo rapidly when meeting the coast. Moreover, it remains a challenge to simulate the exact time andlocation of the extreme precipitation.The coupling of the atmosphere model with the ice-ocean model as well as the increased resolution ofthe atmospheric component have been observed to show great improvements in the model performanceand are suggested for future research work to be used in combination with each other for the regionalmodelling of convective snow bands in the Baltic Sea area.

Organisations comprise human and technical systems that typically perform a variety of business, engineering and production roles. Human systems comprise individuals, people groups and teams that work systematically to conceive, implement, develop and manage the purposes of any enterprise in response to customer requirements. Recently attention has been paid to modelling aspects of people working within production systems, with a view to improving: production performance, effective resource allocation and optimum resource management. In the research reported, graphical and computer executable models of people have been conceived and used in support of human systems engineering. The approach taken has been to systematically decompose and represent processes so that elemental production and management activities can be modelled as explicit descriptions of roles that human systems can occupy as role holders. First of all, a preliminary modelling method (MM1) was proposed for modelling human systems in support of engineering enterprise; then MM1 was implemented and tested in a case study company 1. Based on findings of this exploratory research study an improved modelling method (MM2) was conceived and instrumented. Here characterising customer related product dynamic impacts extended MM1 modelling concepts and methods and related work system changes. MM2 was then tested in case study company 2 to observe dynamic behaviours of selected system models derived from actual company knowledge and data. Case study 2 findings enabled MM2 to be further improved leading to MM3. MM3 improvements stem from the incorporation of so-called DPU (Dynamic Producer Unit) concepts, related to the modelling of human and technical resource system components . Case study 4 models a human system for targeted users i.e. production managers etc to facilitate analysis of human configuration and also cost modelling. Modelling approaches MM2, MM3 and also Case Study 4 add to knowledge about ways of facilitating quantitative analysis and comparison between different human system configurations. These new modelling methods allow resource system behaviours to be matched to specific, explicitly defined, process-oriented requirements drawn from manufacturing workplaces currently operating in general engineering, commercial furniture and white goods industry sectors.

Information technology (IT) plays an important role in contemporary organisations and this role continues to expand in scope and complexity and affects business operations dramatically. Advances in the IT industry have caused major changes in every industry sector. The banking industry is no exception and it has undergone a dramatic change over the past few decades. With the coming of the information age, IS investments are becoming increasingly important to banks` survival, growth and prosperity. IS managers are under increasing pressure to justify the value and contribution of IS expenditure to the productivity, quality and competitiveness of the organisation. This study aims to propose a model which investigates the success of information systems in the banking industry in order to help bank managers to evaluate the success of their IS, to be able to develop these systems and to improve the performance of bank managers and employees. Given that the ultimate dependent variable for this research is individual impacts, DeLone and McLean (2003) updated IS success model is leveraged and extended in this research. The study proposes a research model which is guided by the decision to select a suitable number of key potential demographic and situational variables, in addition to the adoption of DeLone and McLean (2003) updated model. This model proposes that a variety of factors were found to affect IS success in general, however, from the socio-technical viewpoint, IS success should capture both technological and human elements. Therefore, an effective Banking Information System (BIS) typically requires an appropriate combination of both. As such, Thus, the technological dimensions (i.e. system, service and information quality) and the human dimensions (e.g. user satisfaction, perceived system benefits, user involvement, user training, age, education and system use) can be a good starting point when considering suitable constructs for measuring BIS success. The research methodology of this study involved interviews with BIS practitioners and professionals to shape and refine the research model. Further, questionnaire survey was employed to collect data from bank managers in Egyptian banks. Structural Equation Modelling (SEM) using Partial Least Square (PLS) was used to test the research model. Three research models were proposed according to age groups and initial results from PLS analysis reported different results in each research model. Findings indicated that system, information and service quality, level of training, age, length of system use, user involvement and top management support were the main predictors (success constructs) of user satisfaction and individual impacts in the three proposed research models. However, the relationships between these constructs varied according to each age group of managers. The study offers important academic and practical contributions. Firstly, as a contribution to research, the study serves to extend the DeLone and McLean (2003) IS success model by introducing some key human and situational dimensions and confirming certain links in that model with the context of banking industry. The contribution to practice is especially relevant for bank CIOs, software designers and developers looking for ways to improve BIS developments by providing them with directions regarding the BIS success dimensions that should be considered to encourage bank managers to adopt and be more satisfied with BIS which in turn influence their job performance.

Petroleum Development Oman (PDO) and Oman Electricity Transmission Company (OETC) are running the main 132kV power transmission grids in the Sultanate of Oman. In the year 2001, PDO and OETC grids were interconnected with a 132kV Over head transmission line linking Nahada 132kV substation at PDO's side to Nizwa 132kV sub-station at OETC's side. Since then the power exchange between PDO and OETC is driven by the natural impedances of the system and the frequency and power exchange is controlled by manually re-dispatching the generators. In light of the daily load profile and the forecasted Gulf Cooperation Council (GCC) states electrical interconnection, it is a great challenge for PDO and OETC grids operators to maintain the existing operation philosophy. The objective of this research is to investigate Automatic Generation Control (AGC) technology as a candidate to control the grid frequency and the power exchange between PDO and OETC grid. For this purpose, a dynamic power system model has been developed to represent PDO-OETC interconnected power system. The model has been validated using recorded data from the field which has warranted the requirement of refining the model. Novel approaches have been followed during the course of the model refining process which have reduced the modelling error to an acceptable limit. The refined model has then been used to assess the performance of different AGC control topologies. The recommended control topologies have been further improved using sophisticated control techniques like Linear Quadratic Regulator (LQR) and Fuzzy Logic (FL). Hybrid Fuzzy Logic Proportional Integral Derivative (FLPID) AGC controller has produced outstanding results. The FLPID AGC controller parameters have then been optimised using Multidimensional Unconstrained Nonlinear Minimization function (fminsearch) and Particle Swarm Optimisation (PSO) method. The PSO has been proved to be much superior to fminsearch function. The robustness of the LQR, the fminsearch optimized FLPID and the PSO FLPID optimized AGC controllers has been assessed. The LQR robustness found to be slightly better than the FLPID technique. However the FLPID supercedes the LQR due to the limited number of field feedback signals in comparison to the LQR. Finally, a qualitative assessment of the benefits of the ongoing GCC interconnection project on PDO and OETC has been done through modelling approach. The results proved that the GCC interconnection will bring considerable benefits to PDO and OETC but the interconnection capacity between PDO and OETC needs to be enhanced. However, the application of AGC on PDO and OETC will alleviate the PDO-OETC interconnection capacity enhancement imposed by the GCC interconnection.

Cette étude sur le démarrage des turbines à gaz (TAG) s’inscrit dans le cadre de l’hybridation d’un turbomoteur d’hélicoptère avec un objectif de réduction de consommation. En effet, un nouveau mode de vol pour hélicoptère bimoteurs est envisagé avec l’extinction d’un moteur en vol, ce qui permettrai tune économie de carburant de l’ordre de 15% d’après Safran Helicopter Engines. La certification d’untel mode de vol nécessite alors de progresser sur la compréhension de la phase de démarrage de la TAG pour garantir un taux d’échec de redémarrage en vol très faible ainsi qu’une capacité de réactivation d’urgence de la TAG éteinte. Le démarrage se décompose en deux grandes phases, la phase d’allumage et la phase d’accélération. A l’issue d’une étude phénoménologique détaillée, les paramètres d’influence ont été identifiés pour chacune de ces phases. Une campagne d’essais de démarrage au sol et à température ambiante, menée chez Safran Helicopter Engines, a été réalisée pour étudie r la capacité de redémarrage du turbomoteur RTM322. L’analyse des résultats a permis d’étayer l’étude phénoménologique effectuée ainsi que de fournir des données pour alimenter les premiers outils numériques 0D développés au court de cette thèse. Le modèle 0D implémenté permet de reproduire une séquence de démarrage complète, avec une prise en compte simple de l’allumage, et ce jusqu’au régime ralenti. Un travail d’extension des caractéristiques des différents composants et systèmes ainsi qu’une étude de différents phénomènes transitoire sont été nécessaire pour y parvenir. Les résultats d’essais étant cependant quasi-inexistants à bas régime,le modèle possède un certain degré d’incertitude dans ces conditions. Enfin, la capacité de réactivation rapide de la TAG a été étudiée avec l’évaluation des gains de temps potentiellement atteignables d’après les essais et à l’aide du modèle développé. Une campagne d’essais complémentaires dédiée aux faibles régimes et pour des conditions environnementales plus sévères en termes de pression et de température permettrait de réduire le degré d’incertitude des projections ainsi obtenues. Une nouvelle campagne d’essai permettrait aussi de tester les différentes améliorations proposées en termes de réactivation. / This study on the start-up phase of gas turbine engines takes place in the context of the hybridization of a helicopter turboshaft engine with a decreased fuel consumption target. A new flight mode for a twin engine helicopter with the shutdown of one engine in-flight is being considered. For Safran Helicopter Engines, this mode would allow up to 15% of fuel savings. The certification of this flight mode involves improving the understanding of the start-up phase of gas turbine engines towards a close-to-zero failure rate for in-flight restarts as well as a fast restart capability of the shutdown engine. The start-up phase is composed of two main steps: the light-up and the acceleration. A detailed phenomenological study has highlighted the factors influencing the performance for each of these two steps. A test rig campaign at sea level and ambient temperature, performed at Safran Helicopter Engines, took place in order to study the restart capability of the RTM322 turboshaft engine. Analyzing the results of this campaign provided support to the phenomenological study and fed the first 0D numerical tools developed in this thesis with data. The 0D model implemented can simulate a full start-up sequence towards idle speed, with a basic approach to account for the light-up phase. This achievement required working on the extension of the various component characteristics towards sub-idle speeds and also on the different transient phenomena involved. The lack of test rig data at low speed leads to a level of uncertainty in these conditions. Finally, the fast restart capability was studied, with the assessments of time saved potentially achievable from the test rig data and with the model developed in this thesis. A new test rig campaign dedicated to low speed operations with more severe environmental conditions in pressure and temperature would allow to lower the level of uncertainty of the simulation results. This would also be the opportunity to test the various improvements suggested in terms of fast restart.

This thesis presents results of a successful simulation study using CO2-EOR technique to enable production from an offshore heavy oil field, named here as Omega, which is located offshore West Africa at a water depth around 2000 m. The findings and contributions to knowledge are outlined below: 1. Long distance CO2 transportation offshore – The solution to the space and weight constraints offshore with respect to CO2-EOR, is a tie-back via long distance CO2 dense phase transportation from onshore to offshore. 2. Cold heavy oil production (CHOP) using CO2-EOR technique - Based on conditions investigated, Miscible Displacement was found to be more efficient for deepwater production. However, Immiscible Displacement can offer greater reliability with regards to CO2 sequestration. 3. CO2 sequestration during CHOP using CO2-EOR technique – Lower CO2 may be released post start-up operation, followed by gradual decline of CO2 retention after the production peak. CO2 retention increases with increasing reservoir pressure, starting with 17.7 % retention at 800 psig to 32.8 % at 5000 psig, based on peak production analysis. 4. Techno-economic Evaluation – Miscible displacement is asssociated with higher cash flow stream that extend throughout the lifetime of the asset due to continuous production while Immiscible Displacement has a longer payback period (in order of 22 years) due to the time lag between the CO2 injection and the incremental heavy oil production. 5. Mathematical Modelling – Improved mathematical models based on existing theories are proposed, to estimate the CO2 requirement and heavy oil production during CHOP using CO2-EOR technique, and to provide an operating envelope for a wide range of operating conditions. As part of further work, the proposed models will require more refinement and validation across a broad range of operating conditions, could be adapted and modified to increase its predictive capability over time.

Significant penetration of distributed generation (DG) and the increasing automation level available for distribution networks have opened an option of splitting a network into subsystems and operating each as an "autonomous island". This is particularly important when a major contingency occurs. However, there are issues and challenges that must be addressed before islanded operation becomes viable, among which, ensuring seamless switching of a distribution subsystem from grid-connected to islanded mode is critically important. Unless the subsystem is a predesigned microgrid, it is highly possible that the subsystem load demand will exceed the generation capacity of island DGs. Therefore, an appropriate load shedding scheme must be implemented to ensure the islanded subsystem is power balanced. In this thesis, a switching control strategy is designed to deliver seamless islanding switching. This strategy comprises a multiple-DG coordination method and a single-step load shedding scheme. Mathematical studies and time-domain simulations that investigate the transients observed during the islanding switching process are both conducted, and together, they are used to address the transient stability issues of an islanded subsystem. This thesis focuses on a distribution subsystem consisting of a mix of synchronous and inverter-based DGs and a combination of static and dynamic loads. DG modelling and control is first introduced, and based on that, various types of method to achieve multiple-DG coordination, including an innovative multiple-master strategy, are investigated. The widely accepted master-slave strategy is used to coordinate DGs when the subsystem is islanded. The strategy demands a single dispatchable and controllable DG, such as a synchronous generator, to be the master, whilst requires the others, such as intermittent renewable-based DGs, to be the slaves. Dynamic load modelling is another critical part of this thesis. The transient stability of dynamic loads after major disturbances is investigated and then used to design the stability-oriented load shedding priority. The single-step load shedding scheme calculates the load shedding amount based on the power flow at the point of common coupling (PCC) and the spinning reserve available in the island. This scheme is activated by the tripping event of the PCC circuit breaker between the grid and the island, and then priorities the load to be shed according to the priority predetermined from the stability perspective. Mathematical analysis is first conducted on a simple subsystem to investigate the impact of DG settings on the islanding transients. A full-scale subsystem is also simulated in PSCAD/EMTDC and used to verify the effectiveness of the switching control strategy. In time-domain simulations, the subsystem is islanded following either a routine switching event or a permanent grid fault. Various factors that may affect the transient performance are analysed, such as the severity of the fault, the DG penetration level, the fault clearance time and the switching control delay. This thesis concludes that based on the proposed switching control strategy, the concept of seamless switching from grid-connected to islanded operation is technically viable.