The Multi-location Trilemma

The possibility of multilocation --- of one entity having more than one exact location --- is required by several metaphysical theories such as the immanentist theory of universals and three-dimensionalism about persistence. One of the most pressing challenges for multi-location theorists is that of making sense of exact location --- in that extant definitions of exact location entail a principle called Functionality, according to which nothing can have more than one exact location. Recently in a number of promising papers, Antony Eagle has proposed and defended a definition of exact location in terms of weak location that does not entail Functionality. This paper provides the first thorough assessment of Eagle’s proposal. In particular, we argue that it cannot account for (i) location of immanent universals, (ii) multi-location of mereologically changing three-dimensional objects , (iii) multi-location of mereologically complex objects, and (iv) mereologically simple but extended objects

Statistical VS Wave Realism in the Foundations of Quantum Mechanics

Different realistic attitudes towards wavefunctions and quantum states are as old as quantum theory itself. Recently Pusey, Barret and Rudolph (PBR) on the one hand, and Auletta and Tarozzi (AT) on the other, have proposed new interesting arguments in favor of a broad realistic interpretation of quantum mechanics that can be considered the modern heir to some views held by the fathers of quantum theory. In this paper we give a new and detailed presentation of such arguments, propose a new taxonomy of different realistic positions in the foundations of quantum mechanics and assess the scope, within this new taxonomy, of these realistic arguments

Composition, identity, and emergence

Composition as Identity (CAI) is the thesis that a whole is, strictly and literally, identical to its parts, considered collectively. McDaniel [2008] argues against CAI in that it prohibits emergent properties. Recently Sider [2014] exploited the resources of plural logic and extensional mereology to undermine McDaniel’s argument. He shows that CAI identifies extensionally equivalent pluralities – he calls it the Collapse Principle (CP) – and then shows how this identification rescues CAI from the emergentist argument. In this paper I first give a new generalized version of both the arguments. It is more general in that it does not presuppose an atomistic mereology. I then go on to argue that the consequences of CP are rather radical. It entails mereological nihilism, the view that there are only mereological atoms. I finally show that, given a mild assumption about property instantiation, namely that there are no un-instantiated properties, this argument entails that CAI and emergent properties are incompatible after all

The General Relativistic Case for Supersubstantivalism

Super-substantivalism (of the type we’ll consider) roughly comprises two core tenets: (1) the physical properties which we attribute to matter (e.g. charge or mass) can be attributed to spacetime directly, with no need for matter as an extraneous carrier “on top of” spacetime; (2) spacetime is more fundamental than (ontologically prior to) matter. In the present paper, we revisit a recent argument in favour of supersubstantivalism, based on General Relativity. A critique is offered that highlights the difference between (various accounts of) fundamentality and (various forms of) ontological dependence. This affords a metaphysically more perspicuous view of what super-substantivalism’s tenets actually assert, and how it may be defended. We tentatively propose a re-formulation of the original argument that not only seems to apply to all classical physics, but also chimes with a standard interpretation of spacetime theories in the philosophy of physics

Identificazione in anello chiuso di modelli dinamici per controllori predittivi

L'identificazione di sistemi o processi é un campo della modellazione che si pone come obiettivo quello di stimare un modello di un processo reale partendo da test o dati sperimentali. Una fase molto importante della procedura di identificazione é il test sul processo reale e la raccolta dei dati sperimentali. Un buon metodo per ottenere da questi esperimenti dei dati con un alto contenuto di informazioni é quello di operare in assenza di controllo e inserire nel processo una sequenza di ingressi che ecciti a sufficienza il processo. Questa procedura ha peró molti svantaggi dovuti sopratutto al fatto che per un lungo periodo di tempo il processo lavora in assenza di controllo. Per queste ragioni risulta preferibile eseguire i test sul processo in anello chiuso, ma in queste condizioni i metodi di identificazione possono dare origine a modelli affetti da errori, specialmente se gli ingressi sono vincolati. Il calo di prestazioni che si registra se i metodi di identificazione vengono applicati a dati raccolti in anello chiuso puó essere superato mediante l'utilizzo di una particolare tipologia di algoritmi subspace. Apparentemente nulla puó essere fatto peró per risolvere il degrado di prestazioni che si registra nel caso in cui i dati derivano da un loop in cui il regolatore é vincolato. E' proprio questo il cuore del lavoro svolto in questa tesi: sono stati messi a confronto 6 differenti algoritmi di identificazione subspace validi in condizioni di anello chiuso e ne sono state testate le prestazioni in condizioni di vincoli sugli ingressi al processo

Relational Quantum Mechanics and the PBR Theorem: A Peaceful Coexistence

According to Relational Quantum Mechanics (RQM) the wave function $\psi$ is considered neither a concrete physical item evolving in spacetime, nor an object representing the absolute state of a certain quantum system. In this interpretative framework, $\psi$ is defined as a computational device encoding observers' information; hence, RQM offers a somewhat epistemic view of the wave function. This perspective seems to be at odds with the PBR theorem, a formal result excluding that wave functions represent knowledge of an underlying reality described by some ontic state. In this paper we argue that RQM is not affected by the conclusions of PBR's argument; consequently, the alleged inconsistency can be dissolved. To do that, we will thoroughly discuss the very foundations of the PBR theorem, i.e. Harrigan and Spekkens' categorization of ontological models, showing that their implicit assumptions about the nature of the ontic state are incompatible with the main tenets of RQM. Then, we will ask whether it is possible to derive a relational PBR-type result, answering in the negative. This conclusion shows some limitations of this theorem not yet discussed in the literature

Is the world a heap of quantum fragments?

Fragmentalism was originally introduced as a new A-theory of time. It was further refined and discussed, and different developments of the original insight have been proposed. In a celebrated paper, Jonathan Simon contends that fragmentalism delivers a new realist account of the quantum state—which he calls conservative realism—according to which: the quantum state is a complete description of a physical system, the quantum state is grounded in its terms, and the superposition terms are themselves grounded in local goings-on about the system in question. We will argue that fragmentalism, at least along the lines proposed by Simon, does not offer a new, satisfactory realistic account of the quantum state. This raises the question about whether there are some other viable forms of quantum fragmentalism

Surge Exploration Tests and Second Quadrant Characteristic Dynamic Modeling on High Pressure Ratio Compressor (Hprc) Prototype

LecturesHigh Pressure Ratio Compressor (HPRC) technology is based on an innovative architecture that combines unshrouded and shrouded impellers on a single high-speed shaft to achieve pressure ratios and efficiency levels higher than other available technologies. In the final step of the product development and validation, a test campaign has been carried out with the aim to test the performance and explore the operability of the new machine. Surge exploration tests have been also performed allowing an evaluation of the transient behavior and the mechanical robustness of the compressor even during a critical event such as Surge. Compressor Surge has been analyzed under different conditions, forcing the operating point to move beyond the performance envelope in full speed, at low and high pressure levels, and during emergency shut-downs. Thanks to the complex arrangement of the gas loops and several valves used to recycle back the compressed gas, different levels of Surge intensity were induced upon emergency shut-down. The explorations of a fast event like Surge called for special instrumentations, configured to acquire process data both in direct and reverse flow conditions in the most reliable way, with a high frequency sampling for an oil and gas environment. The result of this work is a breakthrough for the tuning of a centrifugal compressor model – not only HPRC ones – to be used for dynamic simulations and prediction of compressor dynamics during Surge events (like Surge cycle frequency and absorbed torque during Second Quadrant operation) in a more reliable and robust way. Surge exploration tests results analysis, in terms of vibrations and thrust loads, together with development of a compressor enhanced dynamic model, allowed a change from a Surge acceptance criterion - based on the time spent on the left of the Surge Limit Line during an Emergency Shutdown event - to a more physics based criterion - based on the acceptable number of Surge cycles, thus increasing selection optimization of additional protections, such as hot/cold gas bypass valves