Dissertations / Theses on the topic 'Simulation tools'

Mestrado em Engenharia Electrónica e Telecomunicações<br>A crescente globalização da Internet e consequente procura de largura de banda nas redes IP existentes fez emergir a necessidade de um melhor planeamento das redes de telecomunicações. Tendo em vista esse fim foram criadas ferramentas aptas a auxiliar a gestão de redes, como software de monitorização, e em particular os simuladores de redes. Estes permitem a obtenção de resultados preciosos sem a consumo de recursos que a criação de uma testbed real requer. Um desses simuladores é o Opnet Modeler, um software comercial que possibilita a configuração de cenários a vários níveis, como as características dos protocolos, perfis de utilizadores e de mobilidade, ou a estrutura e dimensão da rede. Esta dissertação propôe-se a numa primeira parte a analisar vários aspectos respeitantes à utilização do Opnet Modeler no prisma do gestor de redes, em especial em redes à escala de Campus, explorando algumas das vantagens e lacunas na sua utilização para diversos fins, tais como o design ou restruturação de redes e a análise da qualidade de serviço de diferentes aplicações. Uma componente indispensável à gestão de redes é a previsão de qualidade de serviço. O facto do comportamento do tráfego numa rede variar devido a factores como a alteração do número de utilizadores ou dos seus perfis de tráfego, leva a que seja várias vezes necessário estimar o comportamento da rede sem o perfeito conhecimento desta ou dos seus recursos. O nível de tráfego actualmente desperdiçado devido a uma incorrecta estimativa por parte dos ISP’s da utilização de redes mais complexas representa ao mesmo tempo custos desnecessários e recursos subaproveitados. A procura de um modelo de tráfego que possibilite uma aproximação mais exacta dos parâmetros previstos em relação à realidade leva a que haja uma maior investigação nesta área. Nesta dissertação é testado um framework modelador que se baseia apenas em medições (ou resultados de simulações) de tráfego e correspondentes parâmetros de qualidade de serviço dos pontos de acesso da rede, sem o conhecimento a priori da matriz de tráfego e da topologia da rede, para prever a qualidade de serviço em condições distintas. ABSTRACT: The growing Internet globalization and consequent demand for bandwidth in the existing IP networks lead to the emerging need of a better network telecommunications planning. In order to accomplish that, apt network management tools were created, like monitoring software and network simulators, in particular. These allow the collection of precious results exempt of the resources consumption that the use of a real testbed would require. One of those simulators is Opnet Modeler, commercial software that allows to configure the scenarios at multiple levels, like protocol characteristics, profiles and mobility profiles, or the network size and structure. This dissertation proposes to analyze various aspects related to Opnet Modeler use in a network manager perspective, in particular in Campus scale networks, aiming to explore its advantages and gaps when used for goals such as network design or restructuration and for different services’ QoS analysis. One essential component in network management is QoS prediction. The fact that the network traffic behavior varies due to details like the change in the number of users or their traffic profiles, many times leads to the need of assessing the network behavior without the perfect knowledge of the network or its resources. The currently wasted bandwidth by the ISP’s and network managers due to an incorrect assessment of the utilization in more complex networks represents unnecessary costs and wasted resources. The pretension to obtain a traffic model that allows a more exact approximation of the predicted parameters relatively to the reality lead to a major increase in the research in this area. In this dissertation, the evluation of a modeling framework is performed; that model, based only in traffic measurements (or simulation results) and corresponding QoS parameters at the network access points, that is, without the a priori knowledge of the network’s traffic matrix and topology, is able to predict the network’s QoS for different conditions.

<p>Background: Modelling and simulation are important tools for understanding biological systems. Numerous modelling and simulation software tools have been developed for integrating knowledge regarding the behaviour of a dynamic biological system described in mathematical form. The Systems Biology Markup Language (SBML) was created as a standard format for exchanging biochemical network models among tools. However, it is not certain yet whether actual usage and exchange of SBML models among the tools of different purpose and interfaces is assessable. Particularly, it is not clear whether dynamic simulations of SBML models using different modelling and simulation packages are replicable.</p><p>Results: Time series simulations of published biological models in SBML format are performed using four modelling and simulation tools which support SBML to evaluate whether the tools correctly replicate the simulation results. Some of the tools do not successfully integrate some models. In the time series output of the successful</p><p>simulations, there are differences between the tools.</p><p>Conclusions: Although SBML is widely supported among biochemical modelling and simulation tools, not all simulators can replicate time-course simulations of SBML models exactly. This incapability of replicating simulation results may harm the peer-review process of biological modelling and simulation activities and should be addressed accordingly, for example by specifying in the SBML model the exact algorithm or simulator used for replicating the simulation result.</p>

Mechanisms to share information from Mechanical Computer Assisted Design (MCAD) to simulation model have been demonstrated using various approaches. However, in all cases the information sharing is unidirectional - from the MCAD to Multi-Body Systems (MBS) simulation - which lacks the bidirectional mapping required in a concurrent engineering context where both models need to develop in parallel while remaining consistent.We present a modelling library and a model mapping that permits and encourages parallel development of the mechanical assembly in both the MBS simulation and MCAD environments while supporting both bidirectional initial full transfer and incremental updates. Furthermore, with the adopted approach and with a careful selection of the simulation language, MCAD parts can be extended with non-mechanical behaviour in the simulation tool.<br>Des mécanismes pour partager l'information entre un modèle CAD et un modèle de simulation ont été démontrés utilisant divers approches. Pourtant, dans tous les cas, le partage d'information était unidirectionnel - allant du modèle CAD vers le modèle de simulation - donc ne possédant pas les qualités bidirectionnelles nécessaires dans le contexte de l'ingénierie collaborative ou les modèles doivent rester consistantes en permanence.Nous présentons notre librairie de modélisation et de transformations entre modèles qui permettent et encouragent le développement parallèle de l'assemblage mécanique dans les deux environnements de simulation de conception. Notre approche supporte le partage et la synchronisation des deux modèles dans les deux sens et de façon incrémentale si nécessaire. En complément, avec l'approche que nous avons adopté, les modèles mécaniques peuvent être associés a des modèles comportementales non mécanique dans l'outil de simulation.

Approved for public release; distribution is unlimited<br>The purpose of this thesis is to use wargaming and simulation to gain insight into the effective employment of a new Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) system, the Adaptive Joint C4ISR Node (AJCN). The AJCN provides the supported commander with several capabilities, to include: range extension, waveform bridging, signal intelligence, electronic warfare, and information operations. Two methods are used to gain insight to the support generation of the concept of operations for the AJCN's employment. The first method is wargaming. The wargaming method utilized a class of NPS students and the JCATS combat simulation model. The wargaming generated insights concerning the AJCN's employment. The second method is the use of a constructive simulation model, POA 2. Insights gained from the two methods include: the need for commanders to differentiate the AJCN and its supporting platform; the need for effective information processing techniques; the importance of maintaining at least two-tiers of AJCN coverage to enhance situational awareness of the supported units.<br>Major, United States Army<br>Captain, United States Army

Thesis (M.S. in Modeling Virtual Environments and Simulations (MOVES))--Naval Postgraduate School, Sept. 2004.<br>Thesis advisor(s): Saverio M. Manago, Thomas W. Lucas. Includes bibliographical references (p. 87-89). Also available online.

The exponential growth of computing power that we have been used-to since years is about to face new challenges, most notably for technical and economical reasons. It is highly debated when it will be time to go past traditional CMOS technology, but from ITRS data we know that traditional ultra-deep submicron devices are approaching fundamental physical limits. From an economical point of view, the extremely high costs of chip masks and production plants are posing substantial limitations to the development margins. The end of a remarkably successful era in computing is approaching then. It’s the era where Moore’s Law reigns and processing power per dollar doubles every year. A new era, though, is on the horizon [52]: the nanoelectronics era, with ever smaller devices and higher densities, to keep up with pace. Among the envisaged solutions to these arising problems, alternatives to traditional computation have been proposed, in the form of numerous so-called disruptive nanotechnologies. Some of the proposals innovate also the technological approach, moving from the conventional top-down process to a chemical self-assembly process. None of these effort is mature to the point to substitute CMOS any time soon, but this is the right time to be deeply involved in their study and contribute to their progress towards the moment when some of these will provide a valid alternative. The risk, else, would be to miss not just the next evolutionary step, but a revolution in the approach to computation. The fact that a clear winner is far and away from being declared among the competitors stresses the need to study different technology proposals. The scaling of the featured size of devices in disruptive nanotechnologies also requires to deal with added complexity, that is the price to pay for a great density advantage. Many nanotechnologies, and for sure the ones based on chemical self-assembly, suffer from two problems. First, the self-assembly nature of the process renders almost impossible to replicate complex aperiodic structures, as in the CMOS case. Then, the thermodynamical nature of the assembly makes structures sensitive to temperature variations. To put it more simply, disruptive nanotechnologies suffer from greater defect rates with respect to CMOS. Fault-tolerance techniques must be applied to fabrics, irrespective to the architecture of choice. The net gain, we said, on one side is the prospected density advantage, estimated in up to three orders of magnitude with respect to the limits traced by IRTS, plus a ultra-low power consumption: these are among the main reasons driving computational research in the field in this direction. This doctoral work focuses on the need to address specific questions that apply to many disruptive nanotechnologies. • Is it possible to cope with high defect rates? • How to interconnect nanoscale devices or logic blocks? • Which architectures are best fit for these high density devices? These questions are just an exemplification of the many questions that researchers are trying to answer. In our view, there is a methodological problem that has to be solved first and foremost. The problem is about which approach is scientifically sound to get data to answer the aforementioned question. It is our believe that building analytical models first, to study different technologies, would lead to conclusions that could hardly be considered convincing. In [27] we showed how an analytical model, despite its intricacy, is far from close to model the complexity of the system it mimics, and so are the attained results. From a methodological point of view, then, we argue that numerical simulations are needed to tackle the great complexity of these systems, irrespective of technology at hand, and this requires CAD tools specifically designed to study the nascent problems of emerging technology. Unfortunately, to the best of our knowledge, no such tool was developed before this work. Why, then, we observed a tendency to exploit existing tools to cross the bridge between nanotechnologies and nanoarchitectures? Was this due to the fact that existing tools were good at solving the new challenges as well? This could hardly be the reason why. In fact, it is rather difficult, if possible, to put up a toolchain of existing softwares, able to provide a complete workflow from nanodevice simulation to floorplanning, place and route, and nanoarchitecture simulation and evaluation, able to handle nanotechnology-related constraints. This work focuses on the development of such a tool, ToPoliNano. The software functionalities are described in details, alongside with attained results. It has the ability, starting from a circuit by parsing its VHDL description, to target different disruptive nanotechnologies (different Nanoarray-based architectures [143] and NanoMagneticLogics (NML), also known as Magnetic QCA (M-QCA) [76] supported at present time), to place and route it on a floorplan and then simulate it, in an integrated fashion. The tool has been used to study specific architectures devised to exploit the power of emerging technologies. ToPoliNano tool covers a broad range of abstraction levels, from the device level, to the circuit level, up to the architectural level. It is then possible to draw conclusions at architectural level starting from modeling at device level. This is critical to trust architectural results, usually prone to huge errors. Massively parallel architectures were studied to exploit regularity of these fabrics; this approach seems more promising than massive data parallelism. Logic and timing simulations have been performed, and results published in International Journals and Conferences [25, 26, 27, 32, 65, 77]. The organization of this document is as follows. Part I consists in Chapter 1, which is introductory to the technologies handled by ToPoliNano, providing background and state-of-the art information on the subject. Part II opens with Chapter 2, which is about general organization of the application, providing an overview of the specifications and of the most advanced characteristics of the ToPoliNano software. Chapter 3 provides information about the software at two levels of detail: introductory, if the subject is further developed in other parts of the work, informative else. Chapter 4 deals with details of the VHDL parsing module. Chapter 5 deals with details of the Input Stimuli Generator, while Chapter 6 thoroughly details implementation and results of the Simulation Engine(s) of the software. In Chapter 7 a key component for ToPoliNano’s flexibility in dealing with different nanotechnologies is described: the Library Generator. Part II is closed by Chapter 8, in which a case study is presented, with an architecture proposal for biosequence analysis and simulation results.

Wind power is a renewable energy source that is today the fastest growing solution to reduce CO2 emissions in the electric energy mix. Upwind horizontal axis wind turbine with three blades has been the preferred technical choice for more than two decades. This horizontal axis concept is today widely leading the market. The current PhD thesis will cover an alternative type of wind turbine with straight blades and rotating along the vertical axis. A brief overview of the main differences between the horizontal and vertical axis concept has been made. However the main focus of this thesis is the aerodynamics of the wind turbine blades. Making aerodynamically efficient turbines starts with efficient blades. Making efficient blades requires a good understanding of the physical phenomena and effective simulations tools to model them. The specific aerodynamics for straight bladed vertical axis turbine flow are reviewed together with the standard aerodynamic simulations tools that have been used in the past by blade and rotor designer. A reasonably fast (regarding computer power) and accurate (regarding comparison with experimental results) simulation method was still lacking in the field prior to the current work. This thesis aims at designing such a method. Analytical methods can be used to model complex flow if the geometry is simple. Therefore, a conformal mapping method is derived to transform any set of section into a set of standard circles. Then analytical procedures are generalized to simulate moving multibody sections in the complex vertical flows and forces experienced by the blades. Finally the fast semi analytical aerodynamic algorithm boosted by fast multipole methods to handle high number of vortices is coupled with a simple structural model of the rotor to investigate potential aeroelastic instabilities. Together with these advanced simulation tools, a standard double multiple streamtube model has been developed and used to design several straight bladed rotor ranging from 2 kW to 20 kW.<br>Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 704

Avionics Division of Saab AB develops advanced electronics that need to be robust and work in harsh environments with for example extreme temperatures and cosmic radiation without any failure. To succeed with this the electronics need to be simulated and tested. Therefore this thesis work is done to strengthen the Avionics Division’s knowledge of hardware modelling and simulation by evaluating the simulation tools LTSpice, PSpice and SystemVision, their functions and capabilities. In this thesis a survey is carried out with help of a questionnaire to study the Avionics Division’s needs for simulation. The survey is underlying an analysis of the analyses that can be performed by the simulation tools for example Sensitivity analysis, Worst Case analysis, Monte Carlo analysis and Parametric Sweep analysis. The different analyses are discussed in the thesis. The questionnaire is also underlying an analysis of the tools LTSpice, PSpice and SystemVision. The result of the analysis is summarized in Table 1. A case study of a circuit simulation in SystemVision, based on an existing circuit used by Avionics Division, is also done within this thesis work. The study is done to evaluate the tool’s usability, to see if it is easy to perform a simulation and if it is easy to find and use suitable models from the model library. The case study describes how a simulation is performed in SystemVision and how an AC analysis of a Butterworth filter is done. A stability and reliability check of the tool is performed as well as a robustness simulation. The analyses were easy to do and the overall impression is that SystemVision is reliable and user friendly structured. In order to check and compare the results of the AC analysis the same analysis is performed using LTSpice. The comparison shows that the results differ. This depending on that the models of the circuit were some what different in LTSpice and SystemVision. The final conclusion is that SystemVision would fit within Avionics Division’s workflow. Using SystemVision demands education of the engineers to secure maximum use of all the advantages of SystemVision.

This dissertation presents simulation tools developed specifically for the design of solar array power systems. Contributions are made in several aspects of the system design phases, including solar source modeling, system simulation, and controller verification. A tool to automate the study of solar array configurations using general purpose circuit simulators has been developed based on the modeling of individual solar cells. Hierarchical structure of solar cell elements, including semiconductor properties, allows simulation of electrical properties as well as the evaluation of the impact of environmental conditions. A second developed tool provides a co-simulation platform with the capability to verify the performance of an actual digital controller implemented in programmable hardware such as a DSP processor, while the entire solar array including the DC-DC power converter is modeled in software algorithms running on a computer. This "virtual plant" allows developing and debugging code for the digital controller, and also to improve the control algorithm. One important task in solar arrays is to track the maximum power point on the array in order to maximize the power that can be delivered. Digital controllers implemented with programmable processors are particularly attractive for this task because sophisticated tracking algorithms can be implemented and revised when needed to optimize their performance. The proposed co-simulation tools are thus very valuable in developing and optimizing the control algorithm, before the system is built. Examples that demonstrate the effectiveness of the proposed methodologies are presented. The proposed simulation tools are also valuable in the design of multi-channel arrays. In the specific system that we have designed and tested, the control algorithm is implemented on a single digital signal processor. In each of the channels the maximum power point is tracked individually. In the prototype we built, off-the-shelf commercial DC-DC converters were utilized. At the end, the overall performance of the entire system was evaluated using solar array simulators capable of simulating various I-V characteristics, and also by using an electronic load. Experimental results are presented.<br>Ph.D.<br>Department of Electrical and Computer Engineering<br>Engineering and Computer Science<br>Electrical Engineering

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 130-135).<br>The Karlsruhe Tritium Neutrino (KATRIN) experiment is a tritium beta decay experiment designed to make a direct, model independent measurement of the electron neutrino mass. To accomplish this task, the experiment employs precisely defined electric and magnetic fields for particle transport and mass spectroscopy. In order to simulate particle trajectories in the experiment, it is essential to have methods for calculating these fields quickly and accurately. The application of the methods of direct elliptic integral calculation, zonal harmonic expansion and interpolation from an adaptive-refinement field mesh is described within the object-oriented KatrinField framework, as well as an analysis of their comparative strengths and weaknesses in reproducing the electromagnetic fields found in KATRIN.<br>by Thomas Joseph Corona.<br>S.M.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada<br>Advances in high-level architectures in both hardware and software now allow 3D software modeling and interactive simulation to be done from the desktop computer. This paper will address the increasing demand for 3D software modeling and simulation applications throughout the aerospace industry, what kinds of tools are currently available, how operational data is being used in real-world applications, and how to couple real-time data with terrain models and simulation tools to model and analyze operational environments. The following specific areas will be addressed: · The creation of real-world environments by merging virtual objects and ground data with interactive simulation and advanced graphics. · Recent advances in software modeling and simulation tools, which mirror general industry trends. · The ongoing effort to establish standards for modeling and simulation applications throughout the aerospace industry. · Examples of applications using high-level architecture-enabling technology like the visual display of detailed terrain data, drag-and-drop imagery, the enhancement of graphical performance without compromising the quality of rendered data, and expanded support for raster file format images.

Developments in theory and experiment have raised the prospect of an electronic technology based on the discrete nature of electron tunnelling through a potential barrier. This thesis deals with novel design and analysis tools developed to study such systems. Possible devices include those constructed from ultrasmall normal tunnelling junctions. These exhibit charging effects including the Coulomb blockade and correlated electron tunnelling. They allow transistor-like control of the transfer of single carriers, and present the prospect of digital systems operating at the information theoretic limit. As such, they are often referred to as single electronic devices. Single electronic devices exhibit self quantising logic and good structural tolerance. Their speed, immunity to thermal noise, and operating voltage all scale beneficially with junction capacitance. For ultrasmall junctions the possibility of room temperature operation at sub picosecond timescales seems feasible. However, they are sensitive to external charge; whether from trapping-detrapping events, externally gated potentials, or system cross-talk. Quantum effects such as charge macroscopic quantum tunnelling may degrade performance. Finally, any practical system will be complex and spatially extended (amplifying the above problems), and prone to fabrication imperfection. This summarises why new design and analysis tools are required. Simulation tools are developed, concentrating on the basic building blocks of single electronic systems; the tunnelling junction array and gated turnstile device. Three main points are considered: the best method of estimating capacitance values from physical system geometry; the mathematical model which should represent electron tunnelling based on this data; application of this model to the investigation of single electronic systems.

This report provides a comparison of discrete-event simulation tools for supply chain models. We use different simulation tools (Arena and AnyLogic) to analyze and inspect the C14 supply chain management benchmark, as well as, a real-world business supply chain model that is provided by Vantai company in China. In this study, we consider different aspects of these simulation tools (such as, the capability of discrete-event simulation, visualization, simulation efficiency and accuracy, and debugging) to explore their advantages and disadvantages. We hope that our simulation results will have a positive impact on the supply chain management of the companies that provided us with data for this study; furthermore, the comparison results may be useful to developers and researchers in future simulation studies.

Simulation is an effective method for improving supply chain performance. However, there is limited advice available to assist practitioners in selecting the most appropriate method for a given problem. Much of the advice that does exist relies on custom and practice rather than a rigorous conceptual or empirical analysis. An analysis of the different modelling techniques applied in the supply chain domain was conducted, and the three main approaches to simulation used were identified; these are System Dynamics (SD), Discrete Event Simulation (DES) and Agent Based Modelling (ABM). This research has examined these approaches in two stages. Firstly, a first principles analysis was carried out in order to challenge the received wisdom about their strengths and weaknesses and a series of propositions were developed from this initial analysis. The second stage was to use the case study approach to test these propositions and to provide further empirical evidence to support their comparison. The contributions of this research are both in terms of knowledge and practice. In terms of knowledge, this research is the first holistic cross paradigm comparison of the three main approaches in the supply chain domain. Case studies have involved building ‘back to back’ models of the same supply chain problem using SD and a discrete approach (either DES or ABM). This has led to contributions concerning the limitations of applying SD to operational problem types. SD has also been found to have risks when applied to strategic and policy problems. Discrete methods have been found to have potential for exploring strategic problem types. It has been found that discrete simulation methods can model material and information feedback successfully. Further insights have been gained into the relationship between modelling purpose and modelling approach. In terms of practice, the findings have been summarised in the form of a framework linking modelling purpose, problem characteristics and simulation approach.

Interacting species systems have complex dynamics that are often subject to change due to internal and external factors. Quantitative modelling approaches to capture demographic fluctuations can be insufficient in the presence of stochastic variation and uncertainty. This thesis establishes new modelling techniques to account for such demographic variations and develops novel numerical simulation tools for solving these systems. These explorations are extended for solving invasive species management problems where robust management actions and efficient use of allocated budgets are necessary.

CMOS scaling is coming to an end due to limitations such as the increasing leakage current and minimum fabrication sizes achievable. Emerging technologies, that could replace CMOS in next years, are currently under investigation. These technologies will be able to process data at an extremely high operating frequency or with a remarkable reduction of consumed power. The ITRS report summarizes several possible technology solutions, among which carbon nano-tubes and graphene based devices, Quantum-dot Cellular Automata (QCA) and silicon nanowire based nanoarrays. Among these candidates, in this manuscript, the attention is focused on Quantum-dot Cellular Automata, and in particular to the Nano Magnetic Logic(NML) implementation since different studies envisage this technology as a promising alternative to CMOS. The Nano Magnetic Logic working principle is based on the interaction of field-coupled nanomagnets with typical dimension of 60nmx90nm or 50nmx100nm. Information are propagated through chains of these elementary devices according to their ferromagnetic and antiferromagnetic interactions. With this technology, binary information can be encoded in the magnetization verse, indeed, thanks to their very small dimension only two stable states can be recognized: Logic 1 are stored with an up magnetization, while Logic 0 are stored with a down magnetization. The main characteristic of NML are: I) the non-volatility of stored information; II) it is immune to radiation noise and high-energy alpha particles; III) it is an interconnection-free technology; IV) there is the possibility to store logic functions and memory onto the same device and V) it can be easily integrated with CMOS technology. In order to study this technology CAD Tools are needed; this can be useful for architectural explorations and to have terms of comparison with traditional CMOS. The ToPoliNano CAD Tool presented in this manuscript represents the answer to these points, it is able to automatically generate and simulate layouts based on NML starting from and architectural VHDL description. In this scenario, the software implementation of a VHDL parser for the internal representation of circuits represent a key point which makes possible to perform all the operations and the optimizations needed to elaborate the final layout. Another important feature of this instrument is the possibility to verify the correctness of the logical behavior of an NML circuit, for this reason an ad-hoc simulation engine has been developed and validated through a huge number of benchmarks. Thanks to ToPoliNano a thorough study on NML architecture has been made. The main features of ToPoliNano are: I) It is flexible and able to handle different emerging technologies; II) It exploits the same top-down approach of CMOS Tools; III) It is able to generate automatically generate layouts; IV) It allows to verify the correctness of logical NML-based circuits thanks to its specifically tailored simulation engines; V) Since the NML technology is not yet settled we need new techniques to take into account faults derived from the manufacturing process. This thesis focuses therefore on NML logic keeping into account these technology presents also some limitations that can be overcome introducing two other NML implementation: Magneto Tunnel Junctions (MTJ) and perpendicular-NML (pNML) as possible alternative to the traditional in-plane NML (iNML) implementation. Indeed, generally, in iNML circuits, the external fields are made through the use of wires carrying current and placed below the magnetic circuits. This principle has as main drawback, in addition of having high consumption in terms of power, not to allow access to the single cell; in other words, it is not possible to write a particular logical value of a single magnet. This limitation has been overcome by MTJ since cells can be driven through three control signals. In fact, the MJT are often used in combination with the access transistor that allows realizing cycles of read / write of the cells. The third interesting implementation of NML is called perpendicular NML or pNML. The characteristic of this device, with respect to traditional in-plane implementation is the out-of-plane magnetization. In other words, perpendicular NML utilize the perpendicular magnetic anisotropy (PMA); exploiting this principle it is possible to store information depending on the verse of the magnetization. Indeed, exactly like it happened in-plane NML, only two stable states are possible: by convention, the up magnetization is considered as Logic 1 while the down magnetization represents the Logic 0. Here, with respect to the iNML case new features are introduced: I) The switching mechanism is tunable through the manufacturing process; II) The propagation direction of signals is controllable; III) Thanks to its intrinsic prosperities it can be used in 3D structures, exploiting this it is possible to obtain a remarkable area reduction; IV) There is no need of a multiphase clock mechanism to guarantee the information propagation. This unique external magnetic field leads to a remarkable reduction in term of power consumption and a significate simplification in the circuit design process. The methodology followed in this manuscript starts with a technological background of the three NML implementation considered: iNML, pNML and MTJ. Then, for each of them a behavioral model has been developed and then reused to design complex circuits and made architectural explorations. Any limitation identified in the design process has been handled creating specific design rules or trying to overcome them with alternative NML implementations. Moreover, for the iNML technology, a complete design flow has been designed and presented in this manuscript. In particular, the VHDL Parser, the logical (switch level) simulation engine and the LLG-based simulation engine (also with fault analysis tools) will be presented in the following sections.

The Hybrid Warfare phenomena, which is the subject of the current research, has been framed by the work of Professor Agostino Bruzzone (University of Genoa) and Professor Erdal Cayirci (University of Stavanger), that in June 2016 created in order to inquiry the subject a dedicated Exploratory Team, which was endorsed by NATO Modelling &amp; Simulation Group (a panel of the NATO Science &amp; Technology organization) and established with the participation as well of the author. The author brought his personal contribution within the ET43 by introducing meaningful insights coming from the lecture of “Fight by the minutes: Time and the Art of War (1994)”, written by Lieutenant Colonel US Army (Rtd.) Robert Leonhard; in such work, Leonhard extensively developed the concept that “Time”, rather than geometry of the battlefield and/or firepower, is the critical factor to tackle in military operations and by extension in Hybrid Warfare. The critical reflection about the time - both in its quantitative and qualitative dimension - in a hybrid confrontation it is addressed and studied inside SIMCJOH, a software built around challenges that imposes literally to “Fight by the minutes”, echoing the core concept expressed in the eponymous work. Hybrid Warfare – which, by definition and purpose, aims to keep the military commitment of both aggressor and defender at the lowest - can gain enormous profit by employing a wide variety of non-military tools, turning them into a weapon, as in the case of the phenomena of “weaponization of mass migrations”, as it is examined in the “Dies Irae” simulation architecture. Currently, since migration it is a very sensitive and divisive issue among the public opinions of many European countries, cynically leveraging on a humanitarian emergency caused by an exogenous, inducted migration, could result in a high level of political and social destabilization, which indeed favours the concurrent actions carried on by other hybrid tools. Other kind of disruption however, are already available in the arsenal of Hybrid Warfare, such cyber threats, information campaigns lead by troll factories for the diffusion of fake/altered news, etc. From this perspective the author examines how the TREX (Threat network simulation for REactive eXperience) simulator is able to offer insights about a hybrid scenario characterized by an intense level of social disruption, brought by cyber-attacks and systemic faking of news. Furthermore, the rising discipline of “Strategic Engineering”, as envisaged by Professor Agostino Bruzzone, when matched with the operational requirements to fulfil in order to counter Hybrid Threats, it brings another innovative, as much as powerful tool, into the professional luggage of the military and the civilian employed in Defence and Homeland security sectors. Hybrid is not the New War. What is new is brought by globalization paired with the transition to the information age and rising geopolitical tensions, which have put new emphasis on hybrid hostilities that manifest themselves in a contemporary way. Hybrid Warfare is a deliberate choice of an aggressor. While militarily weak nations can resort to it in order to re-balance the odds, instead military strong nations appreciate its inherent effectiveness coupled with the denial of direct responsibility, thus circumventing the rules of the International Community (IC). In order to be successful, Hybrid Warfare should consist of a highly coordinated, sapient mix of diverse and dynamic combination of regular forces, irregular forces (even criminal elements), cyber disruption etc. all in order to achieve effects across the entire DIMEFIL/PMESII_PT spectrum. However, the owner of the strategy, i.e. the aggressor, by keeping the threshold of impunity as high as possible and decreasing the willingness of the defender, can maintain his Hybrid Warfare at a diplomatically feasible level; so the model of the capacity, willingness and threshold, as proposed by Cayirci, Bruzzone and Gunneriusson (2016), remains critical to comprehend Hybrid Warfare. Its dynamicity is able to capture the evanescent, blurring line between Hybrid Warfare and Conventional Warfare. In such contest time is the critical factor: this because it is hard to foreseen for the aggressor how long he can keep up with such strategy without risking either the retaliation from the International Community or the depletion of resources across its own DIMEFIL/PMESII_PT spectrum. Similar discourse affects the defender: if he isn’t able to cope with Hybrid Threats (i.e. taking no action), time works against him; if he is, he can start to develop counter narrative and address physical countermeasures. However, this can lead, in the medium long period, to an unforeseen (both for the attacker and the defender) escalation into a large, conventional, armed conflict. The performance of operations that required more than kinetic effects drove the development of DIMEFIL/PMESII_PT models and in turn this drive the development of Human Social Culture Behavior Modelling (HCSB), which should stand at the core of the Hybrid Warfare modelling and simulation efforts. Multi Layers models are fundamental to evaluate Strategies and Support Decisions: currently there are favourable conditions to implement models of Hybrid Warfare, such as Dies Irae, SIMCJOH and TREX, in order to further develop tools and war-games for studying new tactics, execute collective training and to support decisions making and analysis planning. The proposed approach is based on the idea to create a mosaic made by HLA interoperable simulators able to be combined as tiles to cover an extensive part of the Hybrid Warfare, giving the users an interactive and intuitive environment based on the “Modelling interoperable Simulation and Serious Game” (MS2G) approach. From this point of view, the impressive capabilities achieved by IA-CGF in human behavior modeling to support population simulation as well as their native HLA structure, suggests to adopt them as core engine in this application field. However, it necessary to highlight that, when modelling DIMEFIL/PMESII_PT domains, the researcher has to be aware of the bias introduced by the fact that especially Political and Social “science” are accompanied and built around value judgement. From this perspective, the models proposed by Cayirci, Bruzzone, Guinnarson (2016) and by Balaban &amp; Mileniczek (2018) are indeed a courageous tentative to import, into the domain of particularly poorly understood phenomena (social, politics, and to a lesser degree economics - Hartley, 2016), the mathematical and statistical instruments and the methodologies employed by the pure, hard sciences. Nevertheless, just using the instruments and the methodology of the hard sciences it is not enough to obtain the objectivity, and is such aspect the representations of Hybrid Warfare mechanics could meet their limit: this is posed by the fact that they use, as input for the equations that represents Hybrid Warfare, not physical data observed during a scientific experiment, but rather observation of the reality that assumes implicitly and explicitly a value judgment, which could lead to a biased output. Such value judgement it is subjective, and not objective like the mathematical and physical sciences; when this is not well understood and managed by the academic and the researcher, it can introduce distortions - which are unacceptable for the purpose of the Science - which could be used as well to enforce a narrative mainstream that contains a so called “truth”, which lies inside the boundary of politics rather than Science. Those observations around subjectivity of social sciences vs objectivity of pure sciences, being nothing new, suggest however the need to examine the problem under a new perspective, less philosophical and more leaned toward the practical application. The suggestion that the author want make here is that the Verification and Validation process, in particular the methodology used by Professor Bruzzone in doing V&amp;V for SIMCJOH (2016) and the one described in the Modelling &amp; Simulation User Risk Methodology (MURM) developed by Pandolfini, Youngblood et all (2018), could be applied to evaluate if there is a bias and the extent of the it, or at least making clear the value judgment adopted in developing the DIMEFIL/PMESII_PT models. Such V&amp;V research is however outside the scope of the present work, even though it is an offspring of it, and for such reason the author would like to make further inquiries on this particular subject in the future. Then, the theoretical discourse around Hybrid Warfare has been completed addressing the need to establish a new discipline, Strategic Engineering, very much necessary because of the current a political and economic environment which allocates diminishing resources to Defense and Homeland Security (at least in Europe). However, Strategic Engineering can successfully address its challenges when coupled with the understanding and the management of the fourth dimension of military and hybrid operations, Time. For the reasons above, and as elaborated by Leonhard and extensively discussed in the present work, addressing the concern posed by Time dimension is necessary for the success of any military or Hybrid confrontation. The SIMCJOH project, examined under the above perspective, proved that the simulator has the ability to address the fourth dimension of military and non-military confrontation. In operations, Time is the most critical factor during execution, and this was successfully transferred inside the simulator; as such, SIMCJOH can be viewed as a training tool and as well a dynamic generator of events for the MEL/MIL execution during any exercise. In conclusion, SIMCJOH Project successfully faces new challenging aspects, allowed to study and develop new simulation models in order to support decision makers, Commanders and their Staff. Finally, the question posed by Leonhard in terms of recognition of the importance of time management of military operations - nowadays Hybrid Conflict - has not been answered yet; however, the author believes that Modelling and Simulation tools and techniques can represent the safe “tank” where innovative and advanced scientific solutions can be tested, exploiting the advantage of doing it in a synthetic environment.

Thesis (Ph. D.) -- University of Maryland, College Park, 2007.<br>Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

"The CHTE surface hardening simulation tools, CarboNitrideTool© and CarbTool© have been enhanced to improve the accuracy of the simulation and to predict the microstructure and microhardness profiles after the heat treatment process. These tools can be used for the prediction of both gas and low pressure carburizing processes. The steel alloys in the data base include 10XX, 48XX, 51XX, 86XX, 93XX and Pyrowear 53. They have been used by CHTE members to design efficient carburizing cycles to maximum the profit by controlling the cost and time. In the current software, the model has successfully predicted the carbon concentration profiles for gas carburizing process and many low pressure carburizing processes. In some case, the simulation toll may not work well with the low pressure carburizing process, especially with AISI 9310 alloy. In the previous simulation, a constant carbon flux boundary condition was used. However, it has been experimentally proven that the flux is a function of time. The high carbon potential may cause soot and carbides at the outer edge. The soot and carbides will impede the diffusion of carbon during the low pressure carburizing process. The constant carbon flux cannot be appropriately used as the boundary condition. An improved model for the process is proposed. In the modeling, carbon potential and mass transfer coefficient are calculated and used as the boundary condition. CarbonitrideToolⒸ has been developed for the prediction of both carbon and nitrogen profiles for carbonitriding process. The microstructure and hardness profile is also needed by the industry. The nitrogen is an austenite stabilizer which result in high amount of retained austenite (RA). RA plays important role in the hardness. The model has been developed to predict the Martensite start temperature (Ms) which can be used for RA prediction. Mixture rule is used then to predict the hardness profiles. Experiments has been conducted to verify the simulation. The hardness profile is also predicted for tempered carburized alloys. Hollomon-Jaffe equation was used. A matrix of tempering experiments are conducted to study the Hollomon Jaffe parameter for AISI 8620 and AISI 9310 alloy. Constant C value is calculated with a new mathematical method. With the calculation result, the hardness profile can be predicted with input of tempering time and temperature. Case depth and surface hardness are important properties for carburized steel that must be well controlled. The traditional testing is usually destructive. Samples are sectioned and measured by either OES or microhardness tester. It is time consuming and can only be applied on sampled parts. The heat treating industry needs a physics based, verified simulation tool for surface hardening processes to accurately predict concentration profiles, microstructure and microhardness profiles. There is also a need for non-destructive measurement tool to accurately determine the surface hardness and case depth. Magnetic Barkhausen Noise (MBN) is one of the promising way to test the case depth and hardness. MBN measures the pulses generating by the interaction between magnetic domain walls in the ferromagnetic material and the pinning sites such as carbides, impurities and dislocation. These signals are analyzed to evaluate the properties of the carburized steel. "

This thesis aims at investigating the potentialities of two software tools performing the simulation of the transport and fate of oil spilled at sea: ADIOS2 and the WebGNOME codes, both made freely available by the US NOAA. ADIOS2 gives the oil budget evolution of the spill, that is, it solves the mass balances of the oil present in the different sea compartments. On the other hand, the WebGNOME tool is capable of both solving the oil budget and visualizing the oil slick trajectory. What comes out from the investigation carried out in this thesis is that ADIOS2 is not capable of handling a complete simulation, because it limits the simulation time to 5 days after the start of the spill. Instead, WebGNOME compensates for this lack, allowing to extend the simulation time up to 30 days. By taking a look at the images of the oil slick produced by WebGNOME, it emerges that from day 20 to 30 no major change is seen in the oil slick location. During the first 20 days after the spill, oil beaching occurs on both the northern shoreline and the southern islands of the Santa Barbara Channel, with a total amount of stranded oil equal to 4,800 m3, which accounts for 25 % of the spill. Due to the immediate start of evaporation, 28 % of the oil is transferred from the sea to the atmosphere. At the end of the simulation, floating oil accounts for 6,500 m3, that correspond to 40 % percent; the oil remaining on the sea surface is majorly placed in the outer west side of the Santa Barbara Channel, where it is quite stable, according the last 10 days of the simulation there are negligible changes in the oil budget. It can be claimed that the simulation time of 30 days is sufficient to describe the fate and the transport of the oil slick. In conclusion, the WebGNOME code, which is simple and intuitive to use, requires a limited amount of data, and has short computational times, seems a tool suitable for a preliminary analysis of the consequences of oil spill events at sea.

Thesis (M.S. in Operations Research) Naval Postgraduate School, Sept. 2001.<br>Thesis advisor(s): Buss, Arnold; Miller, Nita. "September 2001." Includes bibliographical references (p. 109-110). Also available in print.

This thesis presents a method for combining GPU programming with traditional programming to create a fluid simulation based watercolor tool for artists. This application provides a graphical interface and a canvas upon which artists can create simulated watercolors in real time. The GPU, or Graphics Processing Unit, is an effcient and highly parallel processor located on the graphics card of a computer; GPU programming is touted as a way to improve performance in graphics and non–graphics applications. The effectiveness of this method in speeding up large, general purpose programs, however, is found here to be disappointing. In a small application with minimal CPU/GPU interaction, theoretical speedups of 10 times maybe achieved, but with the limitations of communication speed between the GPU and the CPU, gains are slight when this method is used in conjunction with traditional programming.

Purpose: The goal of this study is to emphasize the use of business simulation as a learning tool in educational institutions.  For instance, the two master’s programs (marketing &amp; entrepreneurship, provided by Umeå Business School at master’s level), comprised of four core courses each, but only one module out the four provided utilized simulation for learning purpose. Generally self study, class lectures and case studies are used as the main pedagogy tools in the class room setting. In case of Umeå Business School, the use of simulations and gaming was rather limited in Umea School of Business (USBE) despite the fact that simulations are used to the point of saturation in American universities. This research is focused towards exploring the perceptions of students who undertook a business simulation at Umeå Business School, Sweden. Furthermore, it also provides a model for an effective simulation from educational point of view. Method: Hypotheses were developed to investigate the perceptions held by the students at USBE regarding their perceived effectiveness of simulation as a learning tool. A deductive approach was followed by using theories and scientific research by which hypotheses were generated and tested for answering the literature gaps. Quantitative research strategy was used and questionnaires were sent only to qualified respondents (those students of USBE who had already taken simulation at least once in any modules of their study tenure). Hypotheses were generated to find out correlations between the variables and tested through Pearson coefficient using SPSS testing methods. Findings/conclusion: The findings revealed that students consider simulation the most learning tool compared to others. Simulation is considered practical learning, learning through a gaming approach, an exercise that replicates realistic environment in class room. It provides an enjoyable way of learning and the retention of learnt concept is in high to medium range. Empirical findings show that there is a positive correlation between the variable students who would like to use simulation again with the variable that students will register a course which provides simulation. There is a strong positive correlation among variable of perceiving simulation as exciting and variable perceiving it as a fun way of learning.   Positive correlation exists among variables of being excited to know of simulation in a course and variable of considering simulation being a learning experience.   Lastly we found that there is positive and highest correlation in perception of students regarding likeness and learning with regards to simulation.  This means that compared to other tools there is more likeness of simulation amongst students and they perceive it as most learning tool compared to class lectures, guest lectures, self study and group discussions.    The study concluded with providing a basic model of an effective simulation which was developed in line with literature review and empirical findings from this research

Numerical simulation tools are generally used in all modern engineering fields, especially those having difficulties in performing large number of practical experiments, such as biomechanics. Among the computational methods, Finite Element (FE) is an essential tool. Nowadays, the fast-growing computational techniques, from the upgrading hardware to the emerging of novel algorithm, have already enabled extensive applications in biomechanics. For applications that require fast response and/or multiple queries, Reduced Order Modelling (ROM) methods have been developed based on existing methods such as FE, and have eventually enabled real-time numerical simulation for a large variety of engineering problems. In this thesis, several novel computational techniques are developed to explore the capability of Proper Generalised Decomposition (PGD), which is an important approach of ROM. To assess the usability of the PGD-based ROM for biomechanical applications, a real human femur bone is chosen to study its mechanical behaviour as an example. Standard image-based modelling procedure in biomechanics is performed to create an FE model which is then validated with in vitro experimental results. As a basis of this work, the medical image processing has to be performed, in order to generate an available FE model. This model is validated according to data collected from a previously performed \textit{in vitro} experimental test. The full procedure of image-based model generation and the validation of generated model is described in Chapter 2. As a major objective of this thesis, a non-intrusive scheme for the PGD framework is developed in Chapter 3. It is implemented using in-house developed Matlab (Mathworks, USA) code to conduct the PGD work flow, and calling Abaqus as an external solver for devised fictitious mechanical problems. The transformation of data from computed tomography (CT) image set to FE model including inhomogeneous material properties is subjected to some physical constraints, and when applying the load, there are also geometric constraints limiting the locations where load could be applied. These constraints will lead to a constrained parameter space, which possibly has difficulty to be separated in a Cartesian fashion. Therefore, a novel strategy to separate the parameters in a collective manner is proposed in Chapter 4. Chapter 5 details a comprehensive application in biomechanics, the methodologies proposed in Chapter 3 and 4 are applied on the practical model generated in Chapter 2. As a typical application of the PGD vademecum, a material property identification problem is discussed. Further PGD vademecum is generated using the identified material properties with variable loading locations, and with this vademecum, real-time mechanical response of the femur is available. In addition, for the purpose of extending the methodologies to orthotropic materials, which is commonly used in biomechanics, in Chapter 6 another linear elastic model is investigated with the non-intrusive PGD scheme. Nowadays, isogeometric analysis (IGA) is a very popular tool in computational mechanics. It is appealing to take advantage of non-uniform rational B-splines (NURBS) to discretise the model. For PGD, using B-splines for the discretisation of the parameter space could improve the quality of vademecum, especially for problems involving sensitivities with respect to the parameters during the online computations. It is important and necessary to extend the PGD framework to nonlinear solid mechanics, because most biological soft tissues have been observed nonlinear mechanical behaviours. Consequently, in Chapter 7 we have developed a PGD framework for the St.Venant-Kirchhoff constitutive model using the Picard linearisation which is consistent with the fixed-point iteration algorithm commonly used in PGD. In Chapter 8, conclusive remarks are addressed as well as forecasts of possible future works.

The final properties of an alloy are highly interlaced with its microstructure. It is therefore essential to control the evolution of the microstructure of the material during the fabrication process. Nowadays, materials design involves an increasing part of computational design to complement the traditional experimental trial and error approach. Such simulations of the process can decrease the number of material prototypes and shorten the development time for new alloys. In this thesis several microstructure models, aimed for process design, have been suggested. The ambition has been to develop physically based models that are capable to represent the evolution of hundreds of grain or particle sizes, where the models should be possible to run on a standard computer with simulation times less than one day. To achieve this goal, simplified approaches have been suggested, which are accurate enough for the growth rate of grains and particles. The microstructure models have all in common that size distributions of grains or particles are simulated with mean-field approaches. Several of the models also utilize composition and temperature dependent thermodynamic and kinetic properties continually throughout the simulations. These properties have been calculated with programming interfaces to Thermo-Calc and DICTRA together with appropriate thermodynamic and kinetic databases. The materials that have been considered in the present thesis are low alloyed steels, aluminium alloys and cemented carbides. The models are however generic in the sense that all materials can be handled if appropriate thermodynamic, kinetic and property databases exist for the alloy.<br>QC 20110316

This thesis (1) reports the development of simulation tools and control strategies for optimizing hybrid electric vehicle (HEV) energy management, and (2) reports the design and testing of a hydraulic hybrid school bus (HHB) prototype. A hybrid vehicle is one that combines two or more energy sources for use in vehicle propulsion. Hybrid electric vehicles have become popular in the consumer market due to their greatly improved fuel economy over conventional vehicles. The control strategy of an HEV has a paramount effect on its fuel economy performance. In this thesis, backward-looking and forward-looking simulations of three HEV architectures (parallel, power-split and 2-mode power-split) are developed. The Equivalent Cost Minimization Strategy (ECMS), which weights electrical power as an equivalent fuel usage, is then studied in great detail and improvements are suggested. Specifically, the robustness of an ECMS controller is improved by linking the equivalence factor to dynamic programming and then further tailoring its functional form. High-fidelity vehicle simulations over multiple drive-cycles are performed to measure the improved performance of the new ECMS controller, and to show its potential for online application. While HEVs are prominent in the consumer market and studied extensively in current literature, hydraulic hybrid vehicles (HHVs) only exist as heavy utility vehicle prototypes. The second half of this thesis reports design, construction, and testing of a hydraulic hybrid school bus prototype. Design considerations, simulation results, and preliminary testing results are reported, which indicate the strong potential for hydraulic hybrids to improve fuel economy in the school bus vehicle segment.

Simulation models are becoming important engineering tool that helps in design and adjustment of physical systems. This paper shows application of Modelica programing language through Dymola simulation environment in analysis and discussion on control system in district heating substation. As a central component of heating substation, the model of plate heat exchanger water-to-water was created and implemented in Modelica/Dymola. Verification of that model was done by measurements performed at Laboratory of Department of energy and Process Engineering, Norwegian University of Science and Technology. Beside of the heat exchanger model, the heat substation model was completed using components from Buildings library developed at Lawrence Berkley National Laboratory. Afterwards, the substation model was integrated in system of four buildings connected to the district heating network in order to show potentials for lowering supply and return water temperature. It has been proven to be very promising, with benefits such as opportunity for low temperature heat sources and reducing the heat losses in district heating network.This assignment is realised as a part of the collaborative project Sustainable Energy and Environment in Western Balkans that aims to develop and establish five new internationally recognized MSc study programs for the field of Sustainable Energy and Environment, one at each of the five collaborating universities in three different Western Balkan countries. The project is funded through the Norwegian Programme in Higher Education, Research and Development in the Western Balkans, Programme 3: Energy Sector (HERD Energy) for the period 2011-2013.

Anorectal and prostate abnormalities are commonly diagnosed via Digital Rectal Examinations (DRE). DRE is challenging to learn as opportunities for practice are limited, it is hard to standardise, there is a lack of feedback and ineffective assessment since visual cues are minimal, and there is vague information as to what constitutes adequate performance. Traditionally, trainees learn initially on plastic benchtop models and on patients later on. However, models are reported to have severe limitations and awareness of ethical issues has curtailed training opportunities. In order to overcome these limitations, a quantitative approach to better understand DREs via a visualization and analysis framework based on position and pressure sensors is presented, together with a series of progressive haptics-enabled learning tools for knowledge acquisition, procedural skills rehearsal and confidence development that aim to fill the existing gap in traditional teaching methods. These tools allow a trainee to literally see-through whilst practicing on benchtop models, visualise anatomical variability of MRI-scanned healthy volunteers, playback of expert performance, execute a series of Cognitive Task Analysis-based steps, rehearse procedural skills via haptics and deformation modelling of patient-specific anatomy, provide formative and summative feedback, and build up communication skills on a hybrid simulator. Experimental studies to validate the visualisation and analysis framework on both benchtop models and real subjects, and to quantify performance of experts from different specialties are presented. Results of evaluation studies with experts to validate the feedback tool and the haptics-based simulator are discussed, and a pre-evaluation study related to the learning tools with medical students is presented. The proposed quantitative analysis has the potential for enhancing the understanding of DRE, and thus to improve learning. The presented body of knowledge, together with the input from the various clinical specialties that routinely perform DRE, relevant educational theory and innovative technology design, constitute an important contribution that may help overcome limitations of current DRE training methods.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2006.<br>Includes bibliographical references.<br>Recent studies have developed preliminary wiring diagrams for a number of important biological networks. However, the design principles governing the construction and operation of these networks remain mostly unknown. To discover design principles in these networks, we investigated and developed a set of computational tools described below. First, we looked into the application of optimization techniques to explore network topology, parameterization, or both, and to evaluate relative fitness of networks operational strategies. In particular, we studied the ability of an enzymatic cycle to produce dynamic properties such as responsiveness and transient noise filtering. We discovered that non-linearity of the enzymatic cycle allows more effective filtering of transient noise. Furthermore, we found that networks with multiple activation steps, despite being less responsive, are better in filtering transient noise. Second, we explored a method to construct compact models of signal transduction networks based on a protein-domain network representation. This method generates models whose number of species, in the worst case, scales quadratically to the number of protein-domain sites and modification states, a tremendous saving over the combinatorial scaling in the more standard mass-action model was estimated to consist of more that 10⁷ species and was too large to simulate; however, a simplified model consists of only 132 state variables and produced intuitive behavior. The resulting models were utilized to study the roles of a scaffold protein and of a shared binding domain to pathway functions.<br>by Bambang Senoaji Adiwijaya.<br>Ph.D.

In recent years, research on the design and performance evaluation of suboptimal receiver implementations has received considerable attention owing to complexity in the realization of the optimal receiver algorithms over wireless channels. This thesis addresses the effects of using reduced complexity receivers for the Satellite Digital Audio Radio (SDAR), Code Division Multiple Access (CDMA) and UltraWideband (UWB) communications technologies. A graphical-user-interface simulation tool has been developed to predict the link reliability performance of the SDAR services in the continental United States. Feasibility study of receiving both satellite and terrestrial repeater signals using a selection diversity (single antenna) receiver has also been performed. The thesis also develops a general mathematical framework for studying the efficacy of a sub-optimal generalized selection combining (GSC) diversity receiver over generalized fading channel models. The GSC receiver adaptively combines a subset of M diversity paths with the highest instantaneous signal-to-noise ratios (SNR) out of the total L available diversity paths. The analytical framework is applicable for rake receiver designs in CDMA and UWB communications.<br>Master of Science

Numerical simulation tools are generally used in all modern engineering fields, especially those having difficulties in performing large number of practical experiments, such as biomechanics. Among the computational methods, Finite Element (FE) is an essential tool. Nowadays, the fast-growing computational techniques, from the upgrading hardware to the emerging of novel algorithm, have already enabled extensive applications in biomechanics, including mechanical analysis from musculoskeletal or cardiovascular system in macro scale to cell structures or tissue behaviours in micro scale. For applications that require fast response and/or multiple queries, Reduced Order Modelling (ROM) methods have been developed based on existing methods such as FE, and have eventually enabled real-time numerical simulation for a large variety of engineering problems. In this thesis, several novel computational techniques are developed to explore the capability of Proper Generalised Decomposition (PGD), which is an important approach of ROM. To assess the usability of the PGD-based ROM for biomechanical applications, a real human femur bone is chosen to study its mechanical behaviour as an example. Standard image-based modelling procedure in biomechanics is performed to create an FE model which is then validated with in vitro experimental results. As a major contribution, a non-intrusive scheme of the PGD framework is developed and implemented using commonly-used industrial software such as Matlab and Abaqus. It uses Abaqus as an external FE solver, which is called by in-house Matlab codes implementing the PGD algorithms. An example code is available at https://github.com/xizou/NIPGD. This scheme takes advantages of the maturity, robustness and availability of existing FE solvers, and demonstrates a great potential for being applied to industrial projects. To solve parametrised partial differential equations with a parameter space subjected to physical or geometric constraints, a novel strategy is proposed. This strategy provides an approach that collects the most correlated parameters, and then separates them into 2D/3D spaces, instead of separating the parameter space into tensor products of 1D spaces in a Cartesian fashion as it is done in conventional PGD framework. Inspired by the fast-developing methods of isogeometric analysis, it is interesting to borrow the isogeometric idea to exploit the ways of discretising the parameter space inside the PGD framework. The high continuity of B-spline shape functions enables more accurate results for the computation of sensitivities with respect to the parameters. A classical mechanical problem is investigated with orthotropic materials in 2D, with the intention of further application in biomechanics. In addition, an exploration of the generalisation of PGD to nonlinear problems in solid mechanics is presented as another main contribution. Following the large strain theory, Picard linearisation is used to establish a consistent PGD framework within total Lagrange formulation. As a preliminary example, the St.Venant-Kirchhoff constitutive model is adopted. A practical example of the femur bone simulation is provided, the material parameters are obtained through an identification problem using the PGD vademecum, and in a further step, another PGD vademecum is generated for real-time simulation accounting for various loading locations.<br>Numerical simulation tools are generally used in all modern engineering fields, especially those having difficulties in performing large number of practical experiments, such as biomechanics. Among the computational methods, Finite Element (FE) is an essential tool. Nowadays, the fast-growing computational techniques, from the upgrading hardware to the emerging of novel algorithm, have already enabled extensive applications in biomechanics, including mechanical analysis from musculoskeletal or cardiovascular system in macro scale to cell structures or tissue behaviours in micro scale. For applications that require fast response and/or multiple queries, Reduced Order Modelling (ROM) methods have been developed based on existing methods such as FE, and have eventually enabled real-time numerical simulation for a large variety of engineering problems. In this thesis, several novel computational techniques are developed to explore the capability of Proper Generalised Decomposition (PGD), which is an important approach of ROM. To assess the usability of the PGD-based ROM for biomechanical applications, a real human femur bone is chosen to study its mechanical behaviour as an example. Standard image-based modelling procedure in biomechanics is performed to create an FE model which is then validated with in vitro experimental results. As a major contribution, a non-intrusive scheme of the PGD framework is developed and implemented using commonly-used industrial software such as Matlab and Abaqus. It uses Abaqus as an external FE solver, which is called by in-house Matlab codes implementing the PGD algorithms. An example code is available at https://github.com/xizou/NIPGD. This scheme takes advantages of the maturity, robustness and availability of existing FE solvers, and demonstrates a great potential for being applied to industrial projects. To solve parametrised partial differential equations with a parameter space subjected to physical or geometric constraints, a novel strategy is proposed. This strategy provides an approach that collects the most correlated parameters, and then separates them into 2D/3D spaces, instead of separating the parameter space into tensor products of 1D spaces in a Cartesian fashion as it is done in conventional PGD framework. Inspired by the fast-developing methods of isogeometric analysis, it is interesting to borrow the isogeometric idea to exploit the ways of discretising the parameter space inside the PGD framework. The high continuity of B-spline shape functions enables more accurate results for the computation of sensitivities with respect to the parameters. A classical mechanical problem is investigated with orthotropic materials in 2D, with the intention of further application in biomechanics. In addition, an exploration of the generalisation of PGD to nonlinear problems in solid mechanics is presented as another main contribution. Following the large strain theory, Picard linearisation is used to establish a consistent PGD framework within total Lagrange formulation. As a preliminary example, the St.Venant-Kirchhoff constitutive model is adopted. A practical example of the femur bone simulation is provided, the material parameters are obtained through an identification problem using the PGD vademecum, and in a further step, another PGD vademecum is generated for real-time simulation accounting for various loading locations.

Cette thèse s’inscrit dans l’effort international pour construire des réseaux quantiques utilisables par tous. Nous essayons de souligner les problématiques importantes ainsi que les paramètres expérimentaux pouvant être bloquants. Nous explorons différents aspects des réseaux quantiques en vue d’aider la communauté internationale à construire l’Internet quantique. Après avoir introduit certaines notions de base d’informatique quantique pour la compréhension de la suite, nous définissons l’Internet quantique, dégageons les principales problématiques et enjeux. Puis, nous nous penchons sur une série de protocoles, bipartites et multipartites, que nous explicitons. Ensuite, nous étudions la sécurité composable d’un protocole réseau de vérification d’intrication multipartite, utilisé comme bloc de base par de nombreux autres protocoles. Dans le chapitre suivant, nous simulons et analysons différents protocoles de répéteurs quantiques permettant de lier deux nœuds du réseau à grande distance. Ces répéteurs utilisent un défaut dans la structure cristalline du diamant, que nous modélisons. Enfin, les deux derniers chapitres sont dédiés à la construction et à la simulation d’une architecture de réseau quantique transnational qui minimise la quantité de matériel nécessaire pour les utilisateurs du réseau. Nous étudions d’abord un réseau métropolitain, dont nous simulons une instance dans un contexte parisien. Nous exposons les paramètres expérimentaux ainsi que les performances actuelles. Ensuite nous étudions la possibilité d’établir une connexion entre différentes villes quantiques distantes de plusieurs centaines de kilomètres à l’aide de satellites<br>This thesis is written in the context of quantum Internet development. We try here to contribute to the community by discussing some security concerns and by providing detailed models and simulation studies of quantum internet architectures and protocols. We explore different aspects of quantum networks on the path to the Quantum Internet. After introducing basic quantum information notions, we define the Quantum Internet and highlight the main goals and challenges. Then, we list a few bipartite and multipartite applications. After that, we study the composable security of a multipartite entanglement verification protocol, that is used as a building block by many other protocols. In the following chapter, we perform simulations of different quantum repeater protocols allowing connection between two distant nodes. These repeaters use a defect in the crystalline structure of the diamond, that we model. Finally, the last two chapters are dedicated to building and simulating an international quantum network architecture that minimizes the necessary hardware for the end users. We first study a metropolitan network, called the Quantum City, that we simulate in a Parisian context. We highlight the main parameters and today’s performances. Then, we study the feasibility of connecting different quantum cities separated by hundred of kilometers using satellites