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In the last two decades there has been an increasing interest in the field of haptics science. Real-time simulation of haptic interaction with non-rigid deformable object/tissue is computationally demanding. The computational bottleneck in finite- element (FE) modeling of deformable objects is in solving a large but sparse linear system of equations at each time step of the simulation. Depending on the mechanical properties of the object, high-fidelity stable haptic simulations require an update rate in the order of 100 − 1000 Hz. Direct software-based implementations that use conventional computers are fairly limited in the size of the model that they can process at such high rates. In this thesis, a new hardware-based parallel implementation of the iterative Conjugate Gradient (CG) algorithm for solving linear systems of equations is pro- posed. Sparse matrix-vector multiplication (SpMxV) is the main computational kernel in iterative solution methods such as the CG algorithm. Modern micro- processors exhibit poor performance in executing memory-bound tasks such as SpMxV. In the proposed hardware architecture, a novel organization of on-chip memory resources enables concurrent utilization of a large number of fixed-point computing units on a FPGA device for performing the calculations. The result is a powerful parallel computing platform that can iteratively solve the system of equations arising from the FE models of object deformation within the timing constraint of real-time haptics applications. Numerical accuracy of the fixed-point implementation, the hardware architecture design, and issues pertaining to the degree of parallelism and scalability of the solution are discussed in details. The proposed computing platform in this thesis is successfully employed in a set of haptic interaction experiments using static and dynamic linear FE-based models. / Master of Applied Science (MASc)

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Hardware Security Modules (HSMs) are embedded systems that provide a physically secure data storage and handling environment. This master thesis evaluates an HSM method incorporating cryptographic key generation, key management, and tamper protection. The HSM concept involves a sensing mesh structured Physical Unclonable Function (PUF), where the cryptographic key is derived from the sum of cross-sectional area capacitance between conductors on adjacent layers of a flex PCB forming a grid. This sensing mesh PUF that stores a digital fingerprint in its microstructure is used to enclose an internal system extracting and managing the keys. This ensures that accessing the internal structure is unmanageable without modifying the enclosure. Since the cryptographic key is derived from the intrinsic properties within the sensing mesh, modifying it will change its intrinsic properties and change the cryptographic key and make it unusable. The Master thesis contains PCB design and development of a prototype of the PUF system and an associated capacitance measurement system, which can handle and extract unique keys from each copy of the PUFs. A hardware assembling, experimenting, and evaluation procedure were performed regarding the robustness of the PUF and its susceptibility to environmental impacts such as temperature changes, invasive attacks, and agitation. Additionally, an performance evaluation is made by estimating a set of quality factors often associated with PUFs, such as uniqueness, reliability, uniformity, and bit-aliasing on the extracted cryptographic keys. The cryptographic keys provide good reliability in stable conditions for each PUF copy of the population. The cryptographic keys also provide gooduniqueness, uniformity, and bit-aliasing estimations with the quality factors. Moreover, an invasive attack experiment indicates that the PUF enclosure prototype provides tamper detection possibilities together with distinct structure modifications when an intrusion attempt is performed. As stated in theory, PUFs are sensitive to environmental changes, which is also observable in the results when the PUF enclosure prototype is exposed to various environmental conditions. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

The potential of Solid Oxide Fuel Cell Gas Turbine (SOFC/GT) hybrid systems for fuel flexibility makes this technology greatly attractive for system hybridization with various fuel processing units in advanced power generation systems and/or polygeneration plants. Such hybrid technologies open up the possibility and opportunities for improvement of system reliabilities and operabilities. However, SOFC/GT hybrid systems have not yet reached their full potential in term of capitalizing on the synergistic benefits of fuel cell and gas turbine cycles. Integrating fuel cells with gas turbine and other components for transient operations increases the risk for exposure to rapid and significant changes in process dynamics and performance, which are primarily associated with fuel cell thermal management and compressor surge. This can lead to severe fuel cell failure, shaft overspeed, and gas turbine damage. Sufficient dynamic control architectures should be made to mitigate undesirable dynamic behaviours and/or system constraint violations before this technology can be commercialized. But, adequate understanding about dynamic coupling interactions between system components in the hybrid configuration is essential. Considering this critical need for system identification of SOFC/GT hybrid in fuel flexible systems, this thesis investigates the dynamic performance of SOFC/GT hybrid technology in response to fuel composition changes. Hardware-based simulations, which combined actual equipment of direct-fired recuperated gas turbine system and simulated fuel cell subsystem, are used to experimentally investigate the impacts of fuel composition changes on the SOFC/GT hybrid system, reducing potentially large inaccuracies in the dynamic study. The impacts of fuel composition in a closed loop operation using turbine speed control were first studied for the purpose of simplicity. Quantification of safe operating conditions for dynamic operations associated with carbon deposition and compressor stall and surge was done prior to the execution of experimentation. With closed loop tests, the dynamic performance of SOFC/GT hybrid technology due to a transition in gas composition could be uniquely characterized, eliminating the interactive effects of other process variables and disturbances. However, for an extensive system analysis, open loop tests (without turbine speed control) were also conducted such that potential coupling impacts exhibited by the SOFC/GT hybrid during fuel transients could be explored. Detailed characterization of SOFC/GT dynamic performance was performed to identify the interrelationship of each fuel cell variable in response to fuel composition dynamics and their contributions to operability of the system. As a result of lowering LHV content in the fuel feed, which involved a transition from coal-derived syngas to humidified methane composition in the SOFC anode, the system demonstrated a dramatic transient increase in fuel cell thermal effluent with a time scale of seconds, resulting from the conversion of fuel cell thermal energy storage into chemical energy. This transient was highly associated with the dynamics of solid and gas temperatures, heat flux, heat generation in the fuel cell due to perturbations in methane reforming, water-gas shifting, and electrochemical hydrogen oxidation. In turn, the dramatic changes in fuel cell thermal effluent resulting from the anode composition changes drove the turbine transients that caused significant cathode airflow fluctuations. This study revealed that the cathode air mass flow change was a major linking event during fuel composition changes in the SOFC/GT hybrid system. Both transients in cathode air mass flow and anode composition significantly affected the hybrid system performance. Due to significant coupling between fuel composition transitions and cathode air mass flow changes, thermal management of SOFC/GT hybrid systems might be challenging. Yet, it was suggested that modulating cathode air flow offered promise for effective dynamic control of SOFC/GT hybrid systems with fuel flexibility. / Thesis / Doctor of Philosophy (PhD)

An interest in developing the intelligent machine system that works in conjunction with human has been growing rapidly in recent years. A number of studies were conducted to shed light on how to design an interactive, adaptive and assistive machine system to serve a wide range of purposes including commonly seen ones like training, manufacturing and rehabilitation. In the year 2003, Human Adaptive Mechatronics (HAM) was proposed to resolve these issues. According to past research, the focus is predominantly on evaluation of human skill rather than human performance and that is the reason why intensive training and selection of suitable human subjects for those experiments were required. As a result, the pattern and state of control motion are of critical concern for these works. In this research, a focus on human skill is shifted to human performance instead due to its proneness to negligence and lack of reflection on actual work quality. Human performance or Human Performance Index (HPI) is defined to consist of speed and accuracy characteristics according to a well-renowned speed-accuracy trade-off or Fitts' Law. Speed and accuracy characteristics are collectively referred to as speed and accuracy criteria with corresponding contributors referred to as speed and accuracy variables respectively. This research aims at proving a validity of the HPI concept for the systems with different architecture or the one with and without hardware elements. A direct use of system output logged from the operating field is considered the main method of HPI computation, which is referred to as a non-model approach in this thesis. To ensure the validity of these results, they are compared against a model-based approach based on System Identification theory. Its name is due to being involved with a derivation of mathematical equation for human operator and extraction of performance variables. Certain steps are required to match the processing outlined in that of non-model approach. Some human operators with complicated output patterns are inaccurately derived and explained by the ARX models.

I denna rapport beskrivs en utvecklad utbildningssimulator över spårfordon och dess del- komponenter på järnvägen. Simulatorn är en hårdvarubaserad prototyp över ett dörrsystem på spårfordon. Prototypen ska användas av systemspecialister och tekniker inom järnvägs- branschen. Simulatorn ger användare en teknisk demonstration av hur komponenter funge- rar i ett dörrsystem. Prototypen innehåller motor, brytare, reläer och givare. Komponenterna används för att illustrerar funktioner i ett dörrsystem på ett spårfordon. Utbildningssimula- torn kontrolleras med en styrenhet och genom tryckknappar för manuell styrning. För de- monstration av säkerheten vid av och ombordstigning används en optisk givare som symbo- liserar hinderdetektering. Utbildningssimulatorn har två vanliga fel inbyggda: kabelfel och jordfel. En instruktions- manual bestående av ett kretsschema används för felsökning. Kretsschemat över dörrsyste- met används för hitta felen och åtgärda dem. I felanalysen ingår de faktorer som är orsaken till att de vanligaste felen inträffar på ett spårfordon. Dörrsystem tar emot diagnostiska ko- der från en dörrdator som styr prioriteringen på vilka åtgärder som ska göras. / This report is a description of a developed educational simulator over rail vehicles and its components. The simulator is a hardware-based prototype over a door system on rail vehi- cles. System specialists and technicians will use the prototype. The Simulator should give the user a technical demonstration on how components work in a door system. The proto- type consists of motor, switch, relay and sensor. The components are used for illustration of the functions in a door system on a rail vehicle. The educational simulator is controlled with a control unit and with pushbuttons for manual control. For demonstration of the boarding security an optical sensor is used as symbolize for the obstacle detection. The educational simulation has two embedded common faults: cable fault and ground fault. The instruction manual consists of a circuit diagram and is used for troubleshooting. The circuit diagram over the door system is used to find the faults and to correct them. The fault analysis includes the factors, which is the reason for the most common faults to occur in a rail vehicle. Door system receives diagnostic code from a door computer that control priori- tizing for arrangements that will be made.

This dissertation investigates and introduces novel algorithms, theories, and supporting frameworks to significantly improve the growing problem of Internet security. A distributed firewall and active response architecture is introduced that enables any device within a cyber environment to participate in the active discovery and response of cyber attacks. A theory of semantic association systems is developed for the general problem of knowledge discovery in data. The theory of semantic association systems forms the basis of a novel semantic path merger packet classification algorithm. The theoretical aspects of the semantic path merger packet classification algorithm are investigated, and the algorithm's hardware-based implementation is evaluated along with comparative analysis versus content addressable memory. Experimental results show that the hardware implementation of the semantic path merger algorithm significantly outperforms content addressable memory in terms of energy consumption and operational timing.