The increasing volumes of road transportation contribute to congestion on road, which leads to delays and other negative impacts on the reliability of transportation. Moreover, transportation is one of the main contributors to the growth of carbon dioxide equivalent emissions, where the impact of road transportation is significant. Therefore, governmental organizations and private commercial companies are looking for greener transportation solutions to eliminate the negative externalities of road transportation. In this paper, we present a novel solution framework to support the operational-level decisions for intermodal transportation networks using a combination of an optimization model and simulation. The simulation model includes stochastic elements in form of uncertain travel times, whereas the optimization model represents a deterministic and linear multi-commodity service network design formulation. The intermodal transportation plan can be optimized according to different objectives, including costs, time and CO2e emissions. The proposed approach is successfully implemented to real-life scenarios where differences in transportation plans for alternative objectives are presented. The solutions for transportation networks with up to 250 services and 20 orders show that the approach is capable of delivering reliable solutions and identifying possible disruptions and alternatives for adapting the unreliable transportation plans.

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Renewable energy is a critical component in combating climate change. Ocean wave energy is a source of renewable energy that can be harvested using Wave Energy Converters (WECs). One such WEC is the floating Oscillating Water Column (OWC), which has been successfully field tested and warrants further exploration. This research implements a publicly accessible code in MatLab and SimuLink to simulate the dynamics of a floating OWC in the time domain. This code, known as the Floating OWC Iterative Time Series Solver (FlOWCITSS), uses the pressure distribution model paired with state space realization to capture the internal water column dynamics of the WEC and estimate pneumatic power generation. Published experimental results of floating moored structures are then used to validate FlOWCITSS. While FlOWCITSS seemed to capture the period and general nature of the heave, surge, and internal water column dynamics, the magnitude of the response sometimes had errors ranging from 1.5% −37%. This error could be caused by the modeling techniques used, or it could be due to uncertainties in the experiments. The presence of smaller error values shows potential for FlOWCITSS to achieve consistently higher fidelity results as the code undergoes further developments. To demonstrate the use of FlOWCITSS, geometry variations of a Backward Bent Duct Buoy (BBDB) are explored for a wave environment and mooring configuration. The reference model from Sandia National Labs, RM6, performed significantly better than a BBDB with an altered stern geometry for a 3 second wave period, indicating that stern geometry can have a significant impact on pneumatic power performance. / Master of Science / Renewable energy is a critical component in combating climate change. Ocean wave energy is a source of renewable energy that can be converted into electricity using Wave Energy Converters (WECs). One such WEC is the floating Oscillating Water Column (OWC), which has been successfully field tested and warrants further exploration. Floating OWCs are partially submerged floating structures that have an internal chamber which water oscillates in. The motions of the water displace air inside this chamber, causing the air to be forced through a high speed turbine, which generates electricity. This research develops a publicly accessible code using MatLab and SimuLink to evaluate the motions and power generation capabilities of floating OWCs. This code is then validated against physical experiments to verify its effectiveness in predicting the device's motions. This publicly accessible code, known as the Floating OWC Iterative Time Series Solver (FlOWCITSS), showed error ranging from 1.5 % - 37% for the most important motions that are relevant to energy harvesting and power generation. These errors could be caused by the numerical models used, or uncertainties in experimental data. The presence of smaller error values shows potential for FlOWCITSS to achieve consistently higher fidelity results as the code undergoes further developments. To demonstrate the use of FlOWCITSS, geometry variations of floating OWCs are explored.

<p>Simulation of the planing hull in waves has been addressed during the last 25 years and basically been approached by strip methods. This work follows that tradition and describes a time-domain strip model for simulation of the planing hull in waves. The actual fluid mechanical problem is simplified through the strip approach. The load distribution acting on the hull is approximated by determining the section load at a number of hull sections, strips. The section-wise 2-dimensional calculations are expressed in terms of added mass coefficients and used in the formulations of both inertia and excitation forces in the equations of motions. The modeling approach starts from the hypothetic assumption that the transient conditions can be modeled based on those section-wise calculations. The equation of motion is solved in the time-domain. The equation is up-dated at each time step and every iteration step with respect to the momentary distribution of section draught and relative incident velocity between the hull and water and catches the characteristic non-linear behavior of the planing craft in waves.</p><p>The model follows the principles of the pioneering work of E. E. Zarnick differing on model structure and in details such as the modeling of the lift in the transom area. A major part of the work is concerned with experiments and evaluation of simulations with respect to performed model tests and to published experiment data. Simulations of model tests have been performed and comparisons have been made between measured and simulated time series. The link between simulation and experiment is a wave model which is based on a wave height measurement signal. It is developed and evaluated in the thesis.</p><p>The conclusions are in favor of the 2-dimensional approach to modeling the conditions for the planing hull in waves and among further studies is evaluation of simulated loads and motions to full-scale trial measurement data.</p>

La nécessité de simuler des systèmes complexes et multi-physiques est de plus en plus courante dans l’industrie, en particulier avec l’avènement de la conception mécatronique. Ce phénomène couplé à la pression économique poussant les industriels dans la voie de l’optimisation de leurs produits conduit à une augmentation forte des temps de simulation que les progrès techniques ne parviennent pas à compenser. Les travaux menés lors de cette thèse ont permis de proposer une approche hybride analytique/éléments finis pour la simulation temporelle de la dynamique des transmissions par engrenages en présence de non-linéarités de contact. Couplée à une réduction des modèles éléments finis, cette approche permet la résolution rapide de la dynamique d’un réducteur et offre ainsi la possibilité d’intégrer le réducteur comme composant d’un système complexe tel qu’un système mécatronique. La résolution de la dynamique du réducteur peut être menée en parallèle des autres physiques en prenant en compte des couplages forts. L’optimisation d’un tel système est abordée sur un exemple pour clore cette étude. / The need to simulate complex and multi-physics systems is increasingly common in the industry, especially with the advent of mechatronic design. This coupled with economic pressure pushing the industry towards optimizing their products led to a strong increase in simulation time that technological advances can not compensate. An hybrid method analytical/finite element has been developed for the time domain simulation of gear transmissions involving contact non-linearities. Coupled with a reduction of finite element models, this approach allows fast resolution of the dynamics of a gearbox. Consequently, it is possible to integrate a gearbox as a part of a more complex mechatronic system. All physical phenomena involved in such a complex product are solved at the same time allowing strong coupling to be considered. The optimization of such a system is discussed with an example to conclude this study.

This work tries to remedy the practical part of teaching development of software for real-time systems. It does so by creation of a platform on which students can practically learn aspects of development of software for real-time systems. % (feedback control, low level programming). The resulting platform consists of a plant, a visualizer and a controller. The plant represents an industrial machine, the visualizer displays the current state of the plant. The controller drives the plant. Students learn by developing a program for the controller. The resulting platform is realized as a hardware-in-the-loop simulation -- the controller's processor and devices are real hardware, and the plant is a simulated device. The platform has a low cost, low space requirements and it is not easily breakable. Powered by TCPDF (www.tcpdf.org)

Simulation of the planing hull in waves has been addressed during the last 25 years and basically been approached by strip methods. This work follows that tradition and describes a time-domain strip model for simulation of the planing hull in waves. The actual fluid mechanical problem is simplified through the strip approach. The load distribution acting on the hull is approximated by determining the section load at a number of hull sections, strips. The section-wise 2-dimensional calculations are expressed in terms of added mass coefficients and used in the formulations of both inertia and excitation forces in the equations of motions. The modeling approach starts from the hypothetic assumption that the transient conditions can be modeled based on those section-wise calculations. The equation of motion is solved in the time-domain. The equation is up-dated at each time step and every iteration step with respect to the momentary distribution of section draught and relative incident velocity between the hull and water and catches the characteristic non-linear behavior of the planing craft in waves. The model follows the principles of the pioneering work of E. E. Zarnick differing on model structure and in details such as the modeling of the lift in the transom area. A major part of the work is concerned with experiments and evaluation of simulations with respect to performed model tests and to published experiment data. Simulations of model tests have been performed and comparisons have been made between measured and simulated time series. The link between simulation and experiment is a wave model which is based on a wave height measurement signal. It is developed and evaluated in the thesis. The conclusions are in favor of the 2-dimensional approach to modeling the conditions for the planing hull in waves and among further studies is evaluation of simulated loads and motions to full-scale trial measurement data.

The primary objective of the presented research is to develop a class of integrated compact silicon diffractive sensors (CSDS) based on in-plane diffraction gratings. This class of sensors uses a silicon-on-insulator (SOI) substrate to limit costs, exploit established fabrication processes, enable integration of supporting electronics, and use the well-understood telecommunications wavelength of 1.55µm. Sensing is achieved by combining constant-diffraction-efficiency and highly-angularly-selective in-plane resonance-domain diffraction gratings. Detection is based on the diffraction efficiency of the highly angularly selective grating. In this research, the design processes for the constant-diffraction-efficiency and the highly angularly selective gratings are detailed. Grating designs are optimized with rigorous coupled-wave analysis (RCWA) and simulated with finite-difference time-domain (FDTD) analysis. Fabrication results are presented for the CSDS gratings. An inductively coupled plasma (ICP) Bosch etch process enables grating fabrication to within one percent of designed values with nearly vertical sidewalls. Experimental results are presented for individual CSDS gratings, the prototype sensor, and a prototype linear sensor array. The results agree well with simulation. The linear sensor array prototype demonstrates the intrinsic splitting mechanism and forms the basis of a 2-D sensor array. Finally, a toluene sensor was functionally demonstrated. The proof-of-concept device includes a polymer immobilization layer and microfluidic delivery of toluene. Toluene concentrations as low as 100ppm are measured, corresponding to a refractive index change of 3x10⁻⁴ RIU.

<p>Simulation is a good way to gain insight into a system, for example during development, without having to run or build the actual system. This is especially true for real-time systems, which often operate in hazardous environments or control critical entities in the 'real' world, making testing of these systems in their real environment unsafe during development.</p><p>When building simulations, one simulator is not likely to fit every type of simulation project. Therefore, different simulators, which focus on different aspects of simulation, are built. The High Level Architecture (HLA) from the Defense Modeling and Simulation Office (DMSO) is an architecture for distributed simulations providing a means to communicate between different simulations.</p><p>However, the HLA standard has limitations if viewed from a real-time perspective. For example, there is no built-in support for fault tolerance. In this thesis some of the limitations in HLA are identified and an extended architecture that uses a distributed active real-time database as a way to overcome these limitations is presented. One of the major advantages with this new extended HLA architecture is that it is still compliant with HLA, i.e., no modifications have been made to the HLA interfaces.</p>

Small open-deck roll-on/roll-off passenger ferries in Indonesia have a poor safety record. The Indonesian Government is interested in means by which the safety of these vessels can be improved, and this was the main catalyst for commencing research in this area. Any solution should be capable of being retrofitted to both existing vessels and new designs to improve their stability and, hence, their safety. The research therefore focused on the intact stability of the bare hulls, and with addition of side casings, for the vessels for which data was made available by the Indonesian Government. The research covered both quasi-static analysis, based on the objective of meeting the IMO intact stability criteria, and a dynamic approach using time-domain simulation in regular beam waves. A parametric study of the stability parameters of the twenty vessels demonstrated that, without the presence of side casings, the vessels had difficulties in complying with the IMO intact stability criteria. The problems were solved by introducing side casings (watertight spaces above the vehicle deck) either inboard of the vessel’s side-shell plating, or partially inboard and partially outboard of the side shell. The minimum extent (breadth) of side casings required was determined by iteration on each of the twenty vessels, incorporating variations in the height of the centre of gravity and loading conditions. The implementation of the minimum side casings showed that each vessel then met the IMO intact stability criteria. However, the assessment of the vessels’ dynamic stability characteristics using time-domain simulation provided inconsistent results for these vessels with side casings which met the IMO intact stability criteria. For some particular conditions, the existence and the different forms of side casings could decrease vessel survivability by increasing the roll motion amplitudes for both inside and outside casings and could lead the vessel to capsize. The results of the dynamic stability analysis also confirmed the vulnerability of small vessels with small stability parameters to large waves, and the different roll seakeeping behavior of the different vessel stability parameters.