The dark side of the board: advances in chess Kriegspiel

While imperfect information games are an excellent model of real-world problems and tasks, they are often difficult for computer programs to play at a high level of proficiency, especially if they involve major uncertainty and a very large state space. Kriegspiel, a variant of chess making it similar to a wargame, is a perfect example: while the game was studied for decades from a game-theoretical viewpoint, it was only very recently that the first practical algorithms for playing it began to appear. This thesis presents, documents and tests a multi-sided effort towards making a strong Kriegspiel player, using heuristic searching, retrograde analysis and Monte Carlo tree search algorithms to achieve increasingly higher levels of play. The resulting program is currently the strongest computer player in the world and plays at an above-average human level.

Multi Processor Systems On Chip with Configurable Hardware Acceleration

The evolution of the electronics embedded applications forces electronics systems designers to match their ever increasing requirements. This evolution pushes the computational power of digital signal processing systems, as well as the energy required to accomplish the computations, due to the increasing mobility of such applications. Current approaches used to match these requirements relies on the adoption of application specific signal processors. Such kind of devices exploits powerful accelerators, which are able to match both performance and energy requirements. On the other hand, the too high specificity of such accelerators often results in a lack of flexibility which affects non-recurrent engineering costs, time to market, and market volumes too. The state of the art mainly proposes two solutions to overcome these issues with the ambition of delivering reasonable performance and energy efficiency: reconfigurable computing and multi-processors computing. All of these solutions benefits from the post-fabrication programmability, that definitively results in an increased flexibility. Nevertheless, the gap between these approaches and dedicated hardware is still too high for many application domains, especially when targeting the mobile world. In this scenario, flexible and energy efficient acceleration can be achieved by merging these two computational paradigms, in order to address all the above introduced constraints. This thesis focuses on the exploration of the design and application spectrum of reconfigurable computing, exploited as application specific accelerators for multi-processors systems on chip. More specifically, it introduces a reconfigurable digital signal processor featuring a heterogeneous set of reconfigurable engines, and a homogeneous multi-core system, exploiting three different flavours of reconfigurable and mask-programmable technologies as implementation platform for applications specific accelerators. In this work, the various trade-offs concerning the utilization multi-core platforms and the different configuration technologies are explored, characterizing the design space of the proposed approach in terms of programmability, performance, energy efficiency and manufacturing costs.

Use of shared memory in the context of embedded multi-core processors: exploration of the technology and its limits

Modern embedded systems embrace many-core shared-memory designs. Due to constrained power and area budgets, most of them feature software-managed scratchpad memories instead of data caches to increase the data locality. It is therefore programmers’ responsibility to explicitly manage the memory transfers, and this make programming these platform cumbersome. Moreover, complex modern applications must be adequately parallelized before they can the parallel potential of the platform into actual performance. To support this, programming languages were proposed, which work at a high level of abstraction, and rely on a runtime whose cost hinders performance, especially in embedded systems, where resources and power budget are constrained. This dissertation explores the applicability of the shared-memory paradigm on modern many-core systems, focusing on the ease-of-programming. It focuses on OpenMP, the de-facto standard for shared memory programming. In a first part, the cost of algorithms for synchronization and data partitioning are analyzed, and they are adapted to modern embedded many-cores. Then, the original design of an OpenMP runtime library is presented, which supports complex forms of parallelism such as multi-level and irregular parallelism. In the second part of the thesis, the focus is on heterogeneous systems, where hardware accelerators are coupled to (many-)cores to implement key functional kernels with orders-of-magnitude of speedup and energy efficiency compared to the “pure software” version. However, three main issues rise, namely i) platform design complexity, ii) architectural scalability and iii) programmability. To tackle them, a template for a generic hardware processing unit (HWPU) is proposed, which share the memory banks with cores, and the template for a scalable architecture is shown, which integrates them through the shared-memory system. Then, a full software stack and toolchain are developed to support platform design and to let programmers exploiting the accelerators of the platform. The OpenMP frontend is extended to interact with it.

Design and Prototyping High Endurance Multi-Rotor

The topic of this thesis fo cus on the preliminary design and the p erformance analysis of a multirotor platform. A multirotor is an electrically p owered Vertical Take Off (VTOL) machine with more than two rotors that lift and control the platform. Multirotor are agile, compact and robust, making them ideally suited for b oth indo or and outdo or application especially to carry-on several sensors like electro optical multisp ectral sensor or gas sensor. The main disadvantage is the limited endurance due to heavy Li-Po batteries and high disk loading through the use of different small prop ellers. At the same time, the design of the multirotor do es not follow any engineering principle but it follow the ideas of amateurs’ builder. An adaptation of the classic airplane design theory for the preliminary design is implemented to fill the gap and detailed study of the endurance is p erformed to define the right way to make this kind of VTOL platforms.

L'infrastruttura barocca del lavoro di piattaforma. Un'etnografia multi-situata.

Le conseguenze del management algoritmico sui lavoratori sono note tra gli studiosi, ma poche ricerche indagano le possibilità di agency, soprattutto a livello individuale, nella gig-economy. A partire dalla quotidianità del lavoro, l’obiettivo è analizzare le forme di agency esercitate dai platform workers nel settore della logistica dell'ultimo miglio. La ricerca si basa su un'etnografia multi-situata condotta in due paesi molto distanti e riguardante due diversi servizi urbani di piattaforma: il food-delivery in Italia (Bologna, Torino) e il ride-hailing in Argentina (Buenos Aires). Nonostante le differenze, il lavoro di campo ha mostrato diverse continuità tra i contesti geografici. Innanzitutto, le tecnologie digitali giocano un ruolo ambivalente nell'ambiente di lavoro: se la tecnologia è usata dalle aziende per disciplinare il lavoro, costituisce però anche uno strumento che può essere impiegato a vantaggio dei lavoratori. Sia nel ride-hailing che nelle piattaforme di food-delivery, infatti, i lavoratori esprimono la loro agency condividendo pratiche di rimaneggiamento e tattiche per aggirare il despotismo algoritmico. In secondo luogo, la ricerca ha portato alla luce una gran varietà di attività economiche sviluppate ai margini dell'economia di piattaforma. In entrambi i casi le piattaforme intersecano vivacemente le economie informali urbane e alimentano circuiti informali di lavoro, come evidenziato dall'elevata presenza di scambi illeciti: ad esempio, vendita di account, hacking-bots, caporalato digitale. Tutt'altro che avviare un processo di formalizzazione, quindi, la piattaforma sussume e riproduce l’insieme di condizioni produttive e riproduttive dell'informalità (viração), offrendo impieghi intermittenti e insicuri a una massa di lavoratori-usa-e-getta disponibile al sottoimpiego. In conclusione, le piattaforme vengono definite come infrastrutture barocche, intendendo con il barocco tanto la natura ibrida dell'azione che mescola forme di neoliberismo-dal-basso con pratiche di solidarietà tra pari, quanto la progressiva ristrutturazione dei processi di accumulazione all’insegna di una rinnovata interdipendenza tra formale e informale nelle infrastrutture del «mondo a domicilio».

Modelling, simulation and control of rotary-wing aircraft in multi-agent scenario

The topic of this thesis is the design and the implementation of mathematical models and control system algorithms for rotary-wing unmanned aerial vehicles to be used in cooperative scenarios. The use of rotorcrafts has many attractive advantages, since these vehicles have the capability to take-off and land vertically, to hover and to move backward and laterally. Rotary-wing aircraft missions require precise control characteristics due to their unstable and heavy coupling aspects. As a matter of fact, flight test is the most accurate way to evaluate flying qualities and to test control systems. However, it may be very expensive and/or not feasible in case of early stage design and prototyping. A good compromise is made by a preliminary assessment performed by means of simulations and a reduced flight testing campaign. Consequently, having an analytical framework represents an important stage for simulations and control algorithm design. In this work mathematical models for various helicopter configurations are implemented. Different flight control techniques for helicopters are presented with theoretical background and tested via simulations and experimental flight tests on a small-scale unmanned helicopter. The same platform is used also in a cooperative scenario with a rover. Control strategies, algorithms and their implementation to perform missions are presented for two main scenarios. One of the main contributions of this thesis is to propose a suitable control system made by a classical PID baseline controller augmented with L1 adaptive contribution. In addition a complete analytical framework and the study of the dynamics and the stability of a synch-rotor are provided. At last, the implementation of cooperative control strategies for two main scenarios that include a small-scale unmanned helicopter and a rover.

Multi-organ support device for combined extracorporeal carbon dioxide removal and hemofiltration treatments with pump-free solution for ultrafiltration

The use of extracorporeal organ support (ECOS) devices is increasingly widespread, to temporarily sustain or replace the functions of impaired organs in critically ill patients. Among ECOS, respiratory functions are supplied by extracorporeal life support (ECLS) therapies like extracorporeal membrane oxygenation (ECMO) and extracorporeal carbon dioxide removal (ECCO2R), and renal replacement therapies (RRT) are used to support kidney functions. However, the leading cause of mortality in critically ill patients is multi-organ dysfunction syndrome (MODS), which requires a complex therapeutic strategy where extracorporeal treatments are often integrated to pharmacological approach. Recently, the concept of multi-organ support therapy (MOST) has been introduced, and several forms of isolated ECOS devices are sequentially connected to provide simultaneous support to different organ systems. The future of critical illness goes towards the development of extracorporeal devices offering multiple organ support therapies on demand by a single hardware platform, where treatment lines can be used alternately or in conjunction. The aim of this industrial PhD project is to design and validate a device for multi-organ support, developing an auxiliary line for renal replacement therapy (hemofiltration) to be integrated on a platform for ECCO2R. The intended purpose of the ancillary line, which can be connected on demand, is to remove excess fluids by ultrafiltration and achieve volume control by the infusion of a replacement solution, as patients undergoing respiratory support are particularly prone to develop fluid overload. Furthermore, an ultrafiltration regulation system shall be developed using a powered and software-modulated pinch-valve on the effluent line of the hemofilter, proposed as an alternative to the state-of-the-art solution with peristaltic pump.