Thèse de doctorat : Instrumentation et Micro-Électronique : Nancy 1 : 2008. / Titre provenant de l'écran-titre. Bibliogr.

The U.S. Navy has developed in their ships, and is continually improving, electric propulsion, ship service power, and electric loads. The latest topology under design is the integrated power system (IPS). The IPS entails the all electric ship concept with electric propulsion, direct current (DC) distribution, and modular technology. In the all electric ship concept, ship propulsion and ship service loads are powered by alternating current (AC) generation. For the IPS, power electronics conversion is to be utilized to convert alternating current (AC) generation to direct current (DC) distribution. As state-of-the-art power electronics, the Navy plans to use power electronic building blocks (PEBB) technology in its IPS. A U.S. naval shipboard power system is required to be a highly reconfigurable system to enhance its survivability and reliability. Reconfiguration is a change in the shipboard power system state for various reasons such as new topology, changing missions and emergencies. It was decided to study the behavior of a PEBB-based integrated shipboard power system during reconfiguration. Since no real time operation data was available, the problem was studied through the simulation of reconfiguration scenarios on a scaled-down computer model of an IPS in MATLAB. Reconfiguration scenarios were determined and staged, and an AC/DC power system stability assessment methodology was applied by decoupling the IPS test system around an intrazonal bus. The coupled system of the test IPS, consisted of two dynamic 4160 VAC generators, two rectifiers, two DC-DC converters between the rectifiers' output looped bus and the downstream intrazonal 775V busses, inverters, buck converters, AC loads and DC loads. There was modeling of excitation perturbations which introduced errors in the assessment of the stability requiring an approximation analysis. The study found that the DC bus of interest was stable for all nine reconfiguration scenarios staged, but it found that other busses were not stable for two of the scenarios. The study further found that lower stability margins occurred at lower frequencies of about 1Hz for stable scenarios. It concluded that there were tangible benefits to advancing the shipboard power system architecture to the IPS topology because of the good stability results.

The few past years have witnessed a huge leap in the field of the smart grid communication networks in which many theories are being developed, and many applications are being evolved to accommodate the implementation of the smart grid concepts. Distribution power systems are considered to be one of the first leading fields having the strong desire of applying the smart grid concepts; resulting in the emersion of the smart distribution power systems, which are the future visualization of the distribution systems having both the ability of smart acting, and the capabilities of automation, self-healing, and decentralized control. For the sake of the real implementation of the smart distribution power systems, the main functions performed by the traditional systems have to be performed by the new smart systems as well, taking into account the new features and properties of those smart systems. One of those main functions is the ability of power networks optimal reconfiguration to minimize the system’s power loss while preserving the system radial topology. The proposed reconfiguration methodology targets the utilization of a hybrid genetic algorithm with two fuzzy controllers that could converge to the global optimal network configuration with the fastest convergence rate consuming the least computational time. The first fuzzy controller is designed to reject any infeasible system configurations that might show up in the population of the genetic algorithm and violate the system radial topology, while the second fuzzy controller is designed to adapt the mutation rate of the genetic algorithm. Consequently, a novel multi-agent system is proposed and designed to perform the reconfiguration application in smart distribution power systems employing the concepts of distributed processing and decentralized control demanded by those systems. A multi-agent system employs a group of intelligent agents that have the capabilities of autonomy, reactivity, pro-activity, and sociality. Those agents cooperate with each other in order to perform a certain function through their powerful abilities to communicate, socialize, and make a common decision in a decentralized fashion based on the information retrieved from the surrounding environment and compiles with their ultimate objective.

In the past two decades, FPGA has been witnessed from its restricted use as glue logic towards real System-on-Chip (SoC) platforms. Profiting from the great development on semiconductor and IC technologies, the programmability of FPGAs enables themselves wide adoption in all kinds of aspects of embedded designs. Modern FPGAs provide the additional capability of being dynamically and partially reconfigured during the system run-time. The run-time reconfigurability enhances FPGA designs from the sole spatial to both spatial and temporal parallelism, providing more design flexibility for advanced system features. Adaptive computing delegates an advanced computing paradigm in which computation tasks and resources are intelligently managed in correspondence with conditional requirements. In this thesis, we investigate adaptive designs on FPGA platforms: We present a comprehensive and practical design framework for adaptive computing based on the FPGA run-time reconfigurability. It concerns several design key issues in different hardware/software layers, specifically hardware architecture, run-time reconfiguration technical support, OS and device drivers, hardware process scheduler, context switching as well as Inter-Process Communications (IPC). Targeting a special application of data acquisition (DAQ) and trigger systems in nuclear and particle physics experiments, we set up the data streaming model and conduct theoretical analysis on the adaptive system. Three application studies are employed to verify the proposed adaptive design framework: The first application demonstrates a peripheral controller adaptable system aiming at general embedded designs. Through dynamically loading/unloading a NOR flash memory controller and an SRAM controller, both flash memory and SRAM accesses may be accomplished with less resource consumption than in traditional static designs. In the second case, two real algorithm processing engines are adaptively time-multiplexed in the same reconfigurable slot for particle recognition computation. Experimental results reveal the reduced on-chip resource requirements, as well as an approximate processing capability of the peer static design. Taking advantage of the FPGA dynamic reconfigurability, we present in the third application a novel on-FPGA interconnection microarchitecture named RouterLess NoC (RL-NoC). RL-NoC employs the novel design concept of Move Logic Not Data (MLND), and significantly distinguishes itself from the existing interconnection architectures such as buses, crossbars or NoCs. It does not rely on routers to deliver packets hop by hop as canonical NoCs do, but buffers data packets in virtual channels and brings various nodes using run-time reconfiguration to produce or consume them. In comparison with canonical packet-switching NoCs, the routerless architecture features lower design complexity, less resource consumption, higher work frequency, more efficient power dissipation as well as comparable or even higher packet delivery efficiency. It is regarded as a promising interconnection approach in some design scenarios on FPGAs, especially for light-weight applications. / QC 20110531

The few past years have witnessed a huge leap in the field of the smart grid communication networks in which many theories are being developed, and many applications are being evolved to accommodate the implementation of the smart grid concepts. Distribution power systems are considered to be one of the first leading fields having the strong desire of applying the smart grid concepts; resulting in the emersion of the smart distribution power systems, which are the future visualization of the distribution systems having both the ability of smart acting, and the capabilities of automation, self-healing, and decentralized control. For the sake of the real implementation of the smart distribution power systems, the main functions performed by the traditional systems have to be performed by the new smart systems as well, taking into account the new features and properties of those smart systems. One of those main functions is the ability of power networks optimal reconfiguration to minimize the system’s power loss while preserving the system radial topology. The proposed reconfiguration methodology targets the utilization of a hybrid genetic algorithm with two fuzzy controllers that could converge to the global optimal network configuration with the fastest convergence rate consuming the least computational time. The first fuzzy controller is designed to reject any infeasible system configurations that might show up in the population of the genetic algorithm and violate the system radial topology, while the second fuzzy controller is designed to adapt the mutation rate of the genetic algorithm. Consequently, a novel multi-agent system is proposed and designed to perform the reconfiguration application in smart distribution power systems employing the concepts of distributed processing and decentralized control demanded by those systems. A multi-agent system employs a group of intelligent agents that have the capabilities of autonomy, reactivity, pro-activity, and sociality. Those agents cooperate with each other in order to perform a certain function through their powerful abilities to communicate, socialize, and make a common decision in a decentralized fashion based on the information retrieved from the surrounding environment and compiles with their ultimate objective.

This project investigates a self-reconfiguring rSoC (reconfigurable System on Chip) system which automatically and dynamically loads peripheral controllers, based on the peripherals connected to the system. The Xilinx Virtex-II FGPA, which supports dynamic partial reconfiguration, is used as the experimental target. To implement the system, three main areas are investigated: the peripheral auto detection, the dynamic partial reconfiguration mechanism on the FPGA, and the supporting software. The system core is designed as two defined areas on a single FPGA chip. A fixed area is used for the constant logic circuits (such as soft-core CPU) and partial reconfiguration (PR) slots are used for changeable peripheral controllers. The autoconfiguration process involves three different steps: peripheral auto detection, loading of a peripheral hardware interface configuration, and loading of a peripheral software driver. In our system, we successfully implement the mechanism of peripheral dynamic loading on the rSoC system. Four novel features are provided in the system: 1) Peripheral auto detection. Peripheral boards are automatically detected by the system when connected to the system. 2) Peripheral controller hardware bitstream and software driver dynamic loading. The required peripheral controller hardware bitstream for the connected peripheral board is automatically searched for and loaded by the operating system, as well as the required software driver. Manual operations on these processes are also supported. 3) Individual interface to external environment. Each PR slot provides individual interface to peripheral boards. It is configured by each peripheral controller for board-specific connection. 4) The existing system is extensible. The partial reconfiguration mechanism provided in this project supports at least two PR slots. On higher capacity FPGAs, the number of PR slots could be increased. In our existing system, the time used for the dynamic partial reconfiguration process, including the hardware bitstream loading and the software driver loading, is in the order of 10-20ms, which is an insignificant fraction of the Linux boot time.

The problem of optimum restoration after occurrence the outages in a distribution network is an important issue in smart grids. In this kind of networks remote-controlled switches, alternative sources and grid-connected distributed generators (DG) are employed. Therefore, the reliability of the system (corresponding to the frequency of failures and the duration of interruptions) is improved by operating the switches to resupply a part of interrupted system during the repair time. To evaluate the reliability indices in smart grids, neglecting the restoration during the repair time causes the wrong assessment of the network. Thus, considering the rerouting the power during the interruptions seems necessary to calculate the reliability indices. The problem of restoration is formulated as a non-linear integer programming problem with the assistance of the network graph. The circuit graph method is also used to pre-evaluate the feasible interchanging operations to enhance the efficiency of the computations. The topological and operational constraints in this formulation can be found and resolved with the assistance of fundamental cut-set matrix. The optimum restoration schemes is obtained by considering the optimal islanded mode of operation of the DGs which implies maximizing the loading of DGs while not violating their generation capacities. The optimum restoration policies lead us to find the optimum number and location of those manual switches that should be upgraded to the remote-controlled switches. This is a multi-objective problem that contains the contribution of each restoration policy in the reliability improvement and the cost of those switching operations. The proposed algorithm is applied to different standard test systems and the results are compared to the results obtained from other methods and algorithms.

The purpose of this research is to investigate fault management methodologies within Integrated Modular Avionics (IMA) systems, and develop techniques by which the use of dynamic reconfiguration can be implemented to restore higher levels of systems redundancy in the event of a systems fault. A proposed concept of dynamic configuration has been implemented on a test facility that allows controlled injection of common faults to a representative IMA system. This facility allows not only the observation of the response of the system management activities to manage the fault, but also analysis of real time data across the network to ensure distributed control activities are maintained. IMS technologies have evolved as a feasible direction for the next generation of avionic systems. Although federated systems are logical to design, certify and implement, they have some inherent limitations that are not cost beneficial to the customer over long life-cycles of complex systems, and hence the fundamental modular design, i.e. common processors running modular software functions, provides a flexibility in terms of configuration, implementation and upgradability that cannot be matched by well-established federated avionic system architectures. For example, rapid advances of computing technology means that dedicated hardware can become outmoded by component obsolescence which almost inevitably makes replacements unavailable during normal life-cycles of most avionic systems. To replace the obsolete part with a newer design involves a costly re-design and re-certification of any relevant or interacting functions with this unit. As such, aircraft are often known to go through expensive mid-life updates to upgrade all avionics systems. In contrast, a higher frequency of small capability upgrades would maximise the product performance, including cost of development and procurement, in constantly changing platform deployment environments. IMA is by no means a new concept and work has been carried out globally in order to mature the capability. There are even examples where this technology has been implemented as subsystems on service aircraft. However, IMA flexible configuration properties are yet to be exploited to their full extent; it is feasible that identification of faults or failures within the system would lead to the exploitation of these properties in order to dynamically reconfigure and maintain high levels of redundancy in the event of component failure. It is also conceivable to install redundant components such that an IMS can go through a process of graceful degradation, whereby the system accommodates a number of active failures, but can still maintain appropriate levels of reliability and service. This property extends the average maintenance-free operating period, ensuring that the platform has considerably less unscheduled down time and therefore increased availability. The content of this research work involved a number of key activities in order to investigate the feasibility of the issues outlined above. The first was the creation of a representative IMA system and the development of a systems management capability that performs the required configuration controls. The second aspect was the development of hardware test rig in order to facilitate a tangible demonstration of the IMA capability. A representative IMA was created using LabVIEW Embedded Tool Suit (ETS) real time operating system for minimal PC systems. Although this required further code written to perform IMS middleware functions and does not match up to the stringent air safety requirements, it provided a suitable test bed to demonstrate systems management capabilities. The overall IMA was demonstrated with a 100kg scale Maglev vehicle as a test subject. This platform provides a challenging real-time control problem, analogous to an aircraft flight control system, requiring the calculation of parallel control loops at a high sampling rate in order to maintain magnetic suspension. Although the dynamic properties of the test rig are not as complex as a modern aircraft, it has much less stringent operating requirements and therefore substantially less risk associated with failure to provide service. The main research contributions for the PhD are: 1. A solution for the dynamic reconfiguration problem for assigning required systems functions (namely a distributed, real-time control function with redundant processing channels) to available computing resources whilst protecting the functional concurrency and time critical needs of the control actions. 2. A systems management strategy that utilises the dynamic reconfiguration properties of an IMA System to restore high levels of redundancy in the presence of failures. The conclusion summarises the level of success of the implemented system in terms of an appropriate dynamic reconfiguration to the response of a fault signal. In addition, it highlights the issues with using an IMA to as a solution to operational goals of the target hardware, in terms of design and build complexity, overhead and resources.

Purpose: The study aims to explore the supply chain factors that impacts reshoring decisions.Methods: The study followed a qualitative research method based on exploratory research. In order to attain the context of situation-based interpretation, semi-structured interviews were conducted based on two Swedish firms engaged in reshoring initiatives. The collected data were individually analysed followed by a cross-case analyses.Findings: The research findings identified several experiences within the supply chain factors that have an influence over the reshoring decision. Firstly, firms are required to secure the replacement of offshored suppliers in their home country and ensure the access to the abundance of raw materials while reshoring. Secondly, realignments are needed for components to suit with organizational values, integrate to obtain independence from external entities and utilize pre-existing assets to mitigate challenges. Thirdly, increase in customer participation for firm’s product decision and locally produced goods can further enhance brand perception. Lastly, proximity allowed firms to streamline logistical communication, deter investment cost and promote R&D capabilities.Contribution: The study contributes in the knowledge of reshoring through the lens of supply chain management and also provides managerial context for reshoring decisions. The sole focus on supply chain factors enhances the theoretical expansion of reshoring and allowing further study materials into the emerging research field of reshoring. In addition, the research findings from four different supply chain factors allows a multifaceted contribution for organizational managers. Managers can individually or conjointly utilize the ideas on resource, reconfiguration, customer and proximity for reshoring decisions.Conclusions: The results from the study and the fulfilment of the aim shows that reshoring is a case of strategic decision making by firms who aim to secure a better competitive standpoint by repatriating production back to the home country.

This study describes the platform Atmel FPSLIC, which is created by means of the logic arrays FPGA and the micro-sequencer controller AVR. The developmental kit STK594 is described here as well, with its programming possibilities, as for the logic arrays FPGA, as for the micro-sequencers AVR. Also the separate circuit AT94K is described there. This circuit can be programmed by the language VHDL (the field FPGA), or by means of the assembler and language C for the micro-sequencer. All this can be integrated into the one output file by means of program System Designer, comprising a set of software tools for given programming languages and for generation of the whole circuit. Furthermore, the study describes a simple application for the both platform parts. Also the description of the dynamic reconfiguration of the circuit gate part is included.