A Bound on the Number of Integrators Needed to Linearize a Two-input Control System

For nonlinear control systems with two inputs we consider the problem of dynamic feedback linearization. For a restricted class of dynamic compensators that correspond to adding chains of integrators to the inputs, we give an upper bound for the order of the compensator that needs to be considered. Moreover, we show by an example that this bound is sharp

Product Design Education for Circular Economy

Design has continually developed new approaches to find the most appropriate solutions to the growing environmental and social problems. At the same time higher education courses have tried to adapt their curricula accordingly. The most recently proposed model is circular economy. It reinforces the idea of a paradigm shift to a system of closed loops where there is no waste. This article develops a state of the art on the integration of sustainability in product design in higher education and its evolution to embrace circular economy. This analysis includes identifying past experiences, which contents are addressed, what methodologies are used, what type of approach (focused or dispersed) and what are the needs for teaching staff. This paper tries to identify gaps in order to purpose better solution for circular economy integration.info:eu-repo/semantics/publishedVersio

Sustainable development and hospitality education : employers’ perspectives on the relevance for graduate employability

This paper examines hospitality employers’ perspectives of sustainable development and the implications for hospitality education, particularly graduate employability. An exploratory approach is used in this research where semi-structured interviews were conducted with employers of hospitality graduates. The results established that respondents had mixed understandings of the meaning and relevance of sustainable development. These employers are, however, gradually recognising the value of sustainability for their business. Though it is not currently a priority in terms of a critical employability skill specifically for the hotel sector, related industries seem more mindful of the implications of sustainability credentials. Thus, hospitality educators need to take appropriate actions in subject specific areas where sustainable development is critical to employment opportunities, creating more industry ready graduates who are also globally aware citizens

Rethinking Serious Games Design in the Age of COVID-19: Setting the Focus on Wicked Problems

We live in a complex world, in which our existence is defined by forces that we cannot fully comprehend, predict, nor control. This is the world of wicked problems, of which the situation triggered by the COVID-19 pandemic is a notable example. Wicked problems are complex scenarios defined by the interplay of multiple environmental, social and economic factors. They are everchanging, and largely unpredictable and uncontrollable. As a consequence, wicked problems cannot be definitively solved through traditional problem-solving approaches. Instead, they should be iteratively managed, recognizing and valuing our connectedness with each other and the environment, and engaging in joint thinking and action to identify and pursue the common good. Serious games can be key to foster wicked problem management abilities. To this end, they should engage players in collective activities set in contexts simulating real-world wicked problem scenarios. These should require the continuous interpretation of changing circumstances to identify and pursue shared goals, promoting the development of knowledge, attitudes and skill sets relevant to tackle real-world situations. In this paper we outline the nature, implications and challenges of wicked problems, highlighting why games should be leveraged to foster wicked problem management abilities. Then, we propose a theory-based framework to support the design of games for this purpose

In Vivo Evaluation of Cervical Stiffness Evolution during Induced Ripening Using Shear Wave Elastography, Histology and 2 Photon Excitation Microscopy: Insight from an Animal Model

Prematurity affects 11% of the births and is the main cause of infant mortality. On the opposite case, the failure of induction of parturition in the case of delayed spontaneous birth is associated with fetal suffering. Both conditions are associated with precocious and/or delayed cervical ripening. Quantitative and objective information about the temporal evolution of the cervical ripening may provide a complementary method to identify cases at risk of preterm delivery and to assess the likelihood of successful induction of labour. In this study, the cervical stiffness was measured in vivo in pregnant sheep by using Shear Wave Elastography (SWE). This technique assesses the stiffness of tissue through the measurement of shear waves speed (SWS). In the present study, 9 pregnant ewes were used. Cervical ripening was induced at 127 days of pregnancy (term: 145 days) by dexamethasone injection in 5 animals, while 4 animals were used as control. Elastographic images of the cervix were obtained by two independent operators every 4 hours during 24 hours after injection to monitor the cervical maturation induced by the dexamethasone. Based on the measurements of SWS during vaginal ultrasound examination, the stiffness in the second ring of the cervix was quantified over a circular region of interest of 5 mm diameter. SWS was found to decrease significantly in the first 4–8 hours after dexamethasone compared to controls, which was associated with cervical ripening induced by dexamethasone (from 1.779 m/s ± 0.548 m/s, p < 0.0005, to 1.291 m/s ± 0.516 m/s, p < 0.000). Consequently a drop in the cervical elasticity was quantified too (from 9.5 kPa ± 0.9 kPa, p < 0.0005, to 5.0 kPa ± 0.8 kPa, p < 0.000). Moreover, SWE measurements were highly reproducible between both operators at all times. Cervical ripening induced by dexamethasone was confirmed by the significant increase in maternal plasma Prostaglandin E2 (PGE2), as evidenced by the assay of its metabolite PGEM. Histological analyses and two-photon excitation microscopy, combining both Second Harmonic Generation (SHG) and Two-photon Fluorescence microscopy (2PF) contrasts, were used to investigate, at the microscopic scale, the structure of cervical tissue. Results show that both collagen and 2PF-active fibrillar structures could be closely related to the mechanical properties of cervical tissue that are perceptible in elastography. In conclusion, SWE may be a valuable method to objectively quantify the cervical stiffness and as a complementary diagnostic tool for preterm birth and for labour induction success