Predictive Second Order Sliding Control of Constrained Linear Systems with Application to Automotive Control Systems

This paper presents a new predictive second order sliding controller (PSSC) formulation for setpoint tracking of constrained linear systems. The PSSC scheme is developed by combining the concepts of model predictive control (MPC) and second order discrete sliding mode control. In order to guarantee the feasibility of the PSSC during setpoint changes, a virtual reference variable is added to the PSSC cost function to calculate the closest admissible set point. The states of the system are then driven asymptotically to this admissible setpoint by the control action of the PSSC. The performance of the proposed PSSC is evaluated for an advanced automotive engine case study, where a high fidelity physics-based model of a reactivity controlled compression ignition (RCCI) engine is utilized to serve as the virtual test-bed for the simulations. Considering the hard physical constraints on the RCCI engine states and control inputs, simultaneous tracking of engine load and optimal combustion phasing is a challenging objective to achieve. The simulation results of testing the proposed PSSC on the high fidelity RCCI model show that the developed predictive controller is able to track desired engine load and combustion phasing setpoints, with minimum steady state error, and no overshoot. Moreover, the simulation results confirm the robust tracking performance of the PSSC during transient operations, in the presence of engine cyclic variability.Comment: 6 pages, 5 figures, 2018 American Control Conferance (ACC), June 27-29, 2018, Milwaukee, WI, USA. [Accepted in Jan. 2018

Market Integration in the Golden Periphery - the Lisbon/London Exchange, 1854-1891

The existence of a self-regulating arbitrage mechanism under the gold standard has been traditionally considered as one of its main advantages, and attracted a corresponding research interest. This research is arguably relevant not only to test for the efficiency of the “gold points”, but also to study the evolution of financial integration during the so-called first era of globalization. Our first aim with this paper is to contribute to the enlargement of the scope of the literature by considering the case of Portugal that adhered to the system, in 1854, at a much earlier phase than the majority of countries, thus allowing for a broader perspective on the evolution of the efficiency of the foreign exchange market. As a typical “peripheral” country, Portugal can be used as the starting point for a study of the degree of integration of the periphery within the system. Furthermore, the Portuguese exchange also illustrates the role in practice of large players in sustaining currency stability, over and beyond the atomistic forces of arbitrage and speculation assumed in conventional theoretical frameworks. We also address the question of the credibility of the authorities’ commitment to the standard, through the perspective of the target zone literature.

Diet and male fertility: the impact of nutrients and antioxidants on sperm energetic metabolism

none2Diet might affect male reproductive potential, but the biochemical mechanisms involved in the modulation of sperm quality remain poorly understood. While a Western diet is considered a risk factor for male infertility, the Mediterranean diet seems to protect against male infertility; moreover, the role of a vegetarian habitus in the preservation of sperm quality is controversial. The aim of this review is to analyze the molecular effects of single nutrients on sperm quality, focusing on their involvement in biochemical mechanisms related to sperm bioenergetics. It appears that diets rich in saturated fatty acids (SFA) and low in polyunsaturated fatty acids (PUFA) negatively affect sperm quality, whereas unsaturated fatty acids supplementation ameliorates sperm quality. In fact, the administration of PUFA, especially omega-3 PUFA, determined an increase in mitochon- drial energetic metabolism and a reduction in oxidative damage. Carbohydrates and proteins are also nutritional modulators of oxidative stress and testosterone levels, which are strictly linked to sperm mitochondrial function, a key element for sperm quality. Moreover, many dietary natural polyphenols differentially affect (positively or negatively) the mitochondrial function, depending on their concentration. We believe that an understanding of the biochemical mechanisms responsible for sperm quality will lead to more targeted and effective therapeutics for male infertility.openFerramosca, Alessandra; Zara, VincenzoFerramosca, Alessandra; Zara, Vincenz

Cooperative distributed MPC for tracking

This paper proposes a cooperative distributed linear model predictive control (MPC) strategy for tracking changing setpoints, applicable to any finite number of subsystems. The proposed controller is able to drive the whole system to any admissible setpoint in an admissible way, ensuring feasibility under any change of setpoint. It also provides a larger domain of attraction than standard distributed MPC for regulation, due to the particular terminal constraint. Moreover, the controller ensures convergence to the centralized optimum, even in the case of coupled constraints. This is possible thanks to the warm start used to initialize the optimization Algorithm, and to the design of the cost function, which integrates a Steady-State Target Optimizer (SSTO). The controller is applied to a real four-tank plant

From Urban Vulnerabilities to Resilience: Lessons from Messina's Integrated Risk Approach

  In the city of Messina, the multiplicity of vulnerable situations is a distinctive feature and is representative of the pervasiveness of the risk conditions present in the Italian territory. The critical residential tissues are part of an extended geography in which, to the conditions of seismic and hydro geomorphological vulnerability, are added additional criticalities including altered natural resources, abandoned infrastructure, brownfields, quarries, and unregulated landfills, etc. Despite this, for Messina, there is still no urban planning tool capable of interpreting in an integrated way the risks present, which instead continue to be addressed on an emergency basis and individually, without considering the interactions that are generated and of further damage. For these reasons, Messina was chosen as a prototypical case study, at the national level, to start an experimentation aimed at developing an urban planning tool capable of a new integrated approach to risk interpretation and management. In this process, a decisive role was aimed at building an updated knowledge of the territory through the identification of widespread critical conditions using multiple GIS tools and thanks to the interaction of some analytical-specialist readings from different sources. The results of this process are represented in a system of maps that are strongly integrated with each other and constitute a working document for the interdisciplinary group drafting the General Urban Plan

Arterial Stiffness in Chronic Kidney Disease: The Usefulness of a Marker of Vascular Damage

Increased arterial stiffness is a marker of vasculopathy in chronic kidney disease (CKD) patients, suggesting a significant cardiovascular damage. Detection of arterial stiffness provides physicians with useful prognostic information independent of traditional cardiovascular (CV) risk factors. In addition, this knowledge may help guide appropriate therapeutic choices and monitor the effectiveness of antihypertensive therapies. We review the relationship between arterial stiffness and CKD, as well as the prognostic implications of increased arterial stiffness and the potential therapeutic strategies to ameliorate arterial compliance and outcome in CKD

Impairment of goodwill and corporate governance

This Ph.D thesis entitled “Impairment of goodwill and corporate governance” explores the association between the impairment of goodwill according to the international and US accounting standards (IAS 36 and SFAS 142) and the corporate governance system. In brief, the research question aims at verifying if and how different corporate governance actors influence the impairment test choices. Indeed, the impairment of goodwill involves across-the-board most firm functions. The procedures needed to carry out the impairment test cannot be limited only to the accounting domain, being instead necessary merging the competences in the strategic and operational management, in organization and finance with the accounting-related ones. Underlying the impairment of goodwill there are indeed assumptions that are used for both the ordinary and the strategic decisions. The valuations underlying goodwill impairments are meaningful, revealing about internal politics and they are portentous of the management past (because goodwill originates from business combinations) and future (because goodwill is the expression of the expected benefits deriving from the synergies created or from the invisible intangibles of the acquired entity) strategy. The result of the periodic impairment test constitutes a signal of the future strategy of the firm or of the effectiveness of past strategies. Also, the assumptions underlying the impairment procedure derive from the forecasts, which are predicted at different levels within the firm. The development of my research takes into account a conceptual, historical and doctrinal analysis of the goodwill write-offs, mainly in the Italian accounting literature and with a brief overview on the International accounting literature. The reason to explore the evolution of the goodwill notion and treatment through the accounting history moves from the dense and puzzling debate that since the nineteenth century characterised the accounting panorama, leading the goodwill to be one of the most controversial assets. By common consent the process underlying the valuation of goodwill is associated to the entire process to determine the company economic value. From the introduction of Statement of Financial Accounting Standards No. 142 (SFAS 142) in the United States and of International Accounting Standard 36 (IAS 36) in the International Accounting Standards adopter countries, follows several critiques and reservations from academics, practitioners, standard setters and regulators. As far afield as that in recent years both the US Public Company Accounting Oversight Board and the European Financial Reporting Advisory Group questioned whether prior amortisation process was more relevant and reliable. The corporate governance system may moderate the use of discretionary accounting choices, enforcing the overall reliability of financial reporting. On the one hand I investigate the impact that the internal corporate governance mechanisms have on the impairment test. On the other hand I verify whether the external corporate governance mechanisms are able to affect the decision of impairment. Within the internal corporate governance mechanisms I explore the board of directors, the managerial incentives, the insider ownership and the chief financial officer perception on the impairment of goodwill. Within the external corporate governance mechanisms I explore the institutional ownership, state ownership, external auditor and the analysts forecasts likely associations with discretional impairment of goodwill. This study is mainly grounded on the positivist agency theory, supposing that the agent, whether is the management, or the external auditor or different types of shareholders acts in its own interests which usually may not correspond to the best interests of the principal (Jensen and Meckling, 1976; Fama and Jensen, 1983; Jensen, 1983; Eisenhardt, 1989). The empirical analysis comprises the use of diverse research methods such as archival and survey method. This thesis provides a threefold theoretical contribution, contributing to the studies on accounting history, on accounting and on corporate governance. First, it develops a path within the Italian accounting tradition that might be considered as trailblazing of the modern accounting standards. I retrace different approaches on the evaluation issues and on the concept of goodwill that some of the most influential Italian “Economisti Aziendali” emphasised in their writings. From the specific attention devoted to the long-lived assets financial evaluations one can appreciate the multidimensionality of our “Economia Aziendale”, including operations, management and control. As a matter of fact, the impairment of assets constitutes the trait d’union between various functions within the firm, involving beyond accounting also strategy, finance, operation, internal and external control. I thus carefully explore the past accounting literature on the goodwill-related issues, employing a constructive and historical method that led me to build a personal interpretation. Second, as underlined by prior literature, the manipulation of goodwill write-offs makes allocating financial resources highly inefficient, both at the firm and at market levels, and compromises the role of financial reporting as an external control system (Beatty & Weber, 2006; Ramanna and Watts, 2012). Given the important economic and market implications, managers, directors, chief financial officers, shareholders and external auditors carefully assess the estimates underlying the goodwill write-offs (Gu and Lev, 2011; Ramanna and Watts, 2012). Despite this, prior research has not yet systematically investigated whether the corporate governance system influences the write-offs decisions. As a matter of fact, in literature there are conflicting findings on managerial incentives in manipulating the earnings through specific accruals and in detail through assets write-offs. Third, as far as I know there are still unexplored areas of corporate governance’s influence on impairment of goodwill

Set-Point Tracking MPC with Avoidance Features

This work proposes a finite-horizon optimal control strategy to solve the tracking problem while providing avoidance features to the closed-loop system. Inspired by the set-point tracking model predictive control (MPC) framework, the central idea of including artificial variables into the optimal control problem is considered. This approach allows us to add avoidance features into the set-point tracking MPC strategy without losing the properties of an enlarged domain of attraction and feasibility insurances in the face of any changing reference. Besides, the artificial variables are considered together with an avoidance cost functional to establish the basis of the strategy, maintaining the recursive feasibility property in the presence of a previously unknown number of regions to be avoided. It is shown that the closed-loop system is recursively feasible and input-to-state-stable under the mild assumption that the avoidance cost is uniformly bounded over time. Finally, two numerical examples illustrate the controller behavior

Robust Coalitional Model Predictive Control With Predicted Topology Transitions

This article presents a novel clustering model predictive control technique where transitions to the best cooperation topology are planned over the prediction horizon. A new variable, the so-called transition horizon, is added to the optimization problem to calculate the optimal instant to introduce the next topology. Accordingly, agents can predict topology transitions to adapt their trajectories while optimizing their goals. Moreover, conditions to guarantee recursive feasibility and robust stability of the system are provided. Finally, the proposed control method is tested via a simulated eight-coupled tanks plant