38,301 research outputs found
Colle Santo Stefano (Ortucchio, AQ)
No full textDurante l’estate 2014 sono ripresi gli scavi del sito di Colle Santo Stefano (AQ), già sottoposto ad indagini tra il 1988 ed il 2006, ad opera di una équipe dell’Università di Pisa, sotto la direzione scientifica di Giovanna Radi (Radi et alii 2001; Radi, Danese 2003; Fabbri et alii 2011; Petrinelli Pannocchia et alii 2016). Le ricerche hanno interessato due aree distinte, poste rispettivamente ad ovest ed a sud-ovest dell’area interessata dai precedenti scavi
radi-cho/botbots: generate-citation
No full textA synthetic data generation initiative for conversational agents talking with one another
Qualitative Methods in Continuous and Discrete Dynamical Systems
No full textThis chapter gives a general and friendly overview to the qualitative theory of continuous and discrete dynamical systems, as well as some applications to simple dynamic economic models, and is concluded by a section on basic principles and results of optimal control in continuous time, with some simple applications. The chapter aims to introduce some general concepts, notations and a minimal vocabulary concerning the study of the mathematical theory of dynamical systems that are used in the other chapters of the book. In particular, concepts like stability, bifurcations (local and global), basins of attraction, chaotic dynamics, noninvertible maps and critical sets are defined, and their applications are presented in the following sections both in continuous time and discrete time, as well as a brief introduction to optimal control together with some connections to the qualitative theory of dynamical systems and applications in economics
Training and effectiveness of the use of less lethal means of coercion in the Slovenian police
No full textUporaba, uvrščanje in usposabljanje z »manj ubojnimi ali neubojnimi« prisilnimi sredstvi v policijah po svetu oziroma razvitih demokratičnih družbah je del procesa sprejemanja novih prisilnih sredstev. Zaradi spoštovanja človekovih pravic, zagotavljanja splošne varnosti ljudi in upoštevanja visokih standardov pri izvajanju policijskih postopkov se nenehno razvijajo bolj humana prisilna sredstva. Slovenska policija že uporablja in tudi sledi novostim na področju uvajanja milejših prisilnih sredstev, ki so učinkovita pri obvladovanju hujših storilcev in še vedno primerna za uspešno izvajanja zahtevnejših nalog policije. Policijska zakonodaja v Sloveniji sicer ne pozna izraza »manj ubojna prisilna sredstva« ali »neubojna prisilna sredstva«, kakor tudi ni opredeljeno, katera prisilna sredstva bi bila lahko tako imenovana. Glede na nabor prisilnih sredstev bi morda lahko rekli, da so vsa prisilna sredstva razen strelnega orožja manj ubojna oziroma ne ubojna. Moramo pa se zavedati, da je lahko tudi palica ali katero drugo prisilno sredstvo v rokah neizobraženega oziroma neusposobljenega uporabnika nevarno sredstvo in lahko tudi smrtonosno. V preteklosti se je tako tudi pokazalo, da je oseba, zoper katero je bilo uporabljeno eno od milejših prisilnih sredstev (»plinski razpršilec«) umrla. Ugotovljeno je bilo, da obstaja vzročna povezava med uporabo prisilnega sredstva in nastalo posledico, čeprav vzrok smrti ni bil potrjen kot uporaba prisilnega sredstva. Zaradi takšnih dogodkov se moramo zavedati sekundarnih posledic uporabe prisilnih sredstev, ki so lahko hujše od pričakovanih učinkov uporabe prisilnega sredstva. Zaradi učinkovitega izvrševanja policijskih nalog z uporabo prisilnih sredstev, je treba vseskozi stremeti k uvajanju novih učinkovitejših prisilnih sredstev, predvsem pa takšnih, ki na osebah povzročajo najmanjše posledice. Ker pa je nemogoče z gotovostjo vnaprej določiti, kakšna posledica bo nastala ob uporabi določenega prisilnega sredstva, bi bilo mogoče razmišljati glede imenovanja teh sredstev kot »manj ubojna prisilna sredstva. Učinek manj ubojnih prisilnih sredstev pa je, kot je že povedano mogoče doseči s konstruiranjem le-teh, da so manj nevarna, in pa seveda z rednim in profesionalnim pristopom k usposabljanju in izobraževanju policistov glede same uporabe le teh.
V zaključnem delu želimo preučiti zakonodajo in pooblastila ter predstaviti različna prisilna sredstva v slovenski policiji ter poiskati ustrezno poimenovanje prisilnih sredstev, saj se v različnih dostopnih literaturah uporablja različna terminologija, kot zasledimo nesmrtonosna sila, manj ubojna sredstva, milejša sredstva itd. Izpostavili smo tudi pomembnost usposabljanja v slovenski policiji.
Na osnovi analiziranja obstoječega strokovnega gradiva in spoznanja smo prve štiri hipoteze potrdili, zadnjo smo pa zavrnili.The use, classification and training with "less lethal or non-lethal" means of coercion in police forces around the world, or in developed democratic societies, is part of the process of adopting new means of coercion. In order to respect human rights, ensure the general safety of people and observe high standards in the implementation of police procedures, more humane means of coercion are constantly being developed. The Slovenian police already uses and also follows innovations in the field of introducing milder means of coercion, which are effective in controlling more serious criminals and are still suitable for the successful implementation of more demanding police tasks. Police legislation in Slovenia does not recognize the terms "less lethal means of coercion" or "non-lethal means of coercion", nor is it defined which means of coercion could be called that. Considering the range of coercive means, it could perhaps be said that all coercive means, except for firearms, are less lethal or non-lethal. However, we must be aware that even a stick or any other means of coercion in the hands of an ignorant or untrained user can be a dangerous tool and can be deadly. In the past, it has also been shown that the person against whom one of the milder means of coercion, the "gas spray", was used, died. It was established that there is a causal connection between the use of a coercive instrument and the resulting consequence, despite the fact that the cause of death was not confirmed as the use of a coercive instrument. Because of such events, we must be aware of the secondary consequences of the use of coercive means, which may be worse than the expected effects of their use. Due to the effective execution of police tasks using coercive means, it is necessary to constantly look at the introduction of new more effective coercive means, especially those that cause the least consequences on people. However, since it is impossible to determine with certainty in advance what the consequences will be when a certain means of coercion is used, it would be possible to think about naming these means as "less lethal means of coercion." The effect of less lethal means of coercion, as already said, can be achieved by designing them to be less dangerous and, of course, with a regular and professional approach to the training and education of police officers regarding the actual use of these means.
In the final part, we want to examine the legislation and powers and present the various means of coercion in the Slovenian police and find the appropriate name for the means of coercion, as different terminology is used in the various available literature, as we can see non-lethal force, less lethal means, milder means, etc. We also highlighted the importance of training in the Slovenian police.
Based on the analysis of existing professional material and knowledge, we confirmed the first four hypotheses, but rejected the last one
Indentation of a free beam resting on an elastic substrate with an internal lengthscale
No full textThe plane strain problem of a slender and weightless beam-plate loaded by a transversal point force in unilateral contact with a couple stress elastic foundation is investigated. The study aims to explore the consequences of the material internal lengthscale on the contact mechanics. In particular, compatibility between the beam and the foundation surface demands that both displacement and rotation match along the contact line. To this aim, couple tractions are exchanged besides the traditional contact pressure until separation between the beam and the foundation occurs. The problem is formulated making use of the Green's functions for a point force and a point couple acting atop of a couple stress elastic half-plane. A pair of coupled integral equations is thus derived, that governs the distribution of contact pressure and couple tractions, with one of them being immediately solved to provide an explicit relation between the two unknowns. In this sense, we retrieve the concept of a mechanically equivalent action, as it is the case of the Kirchhoff shear for plates. The remaining integral equation sets a cubic eigenvalue problem, whose linear term accounts for the microstructure. Its numerical solution is sought by expanding the equivalent contact pressure in series of Chebyshev polynomials vanishing at the contact region ends points, namely the lift-off points, and then applying a collocation strategy. The contact length, the distributions of contact pressure and couple tractions under the beam and the shearing force and bending moment along the beam are then obtained as a function of the material characteristic length. Results clearly indicate that accounting for the material internal lengthscale is mainly realized through exchange of the couple tractions, in the lack of which results much resemble those of the classical solution. Specifically, greater contact lengths and a stronger focusing effect about the loading point are encountered, which become very significant when the contact length approaches the internal lengthscale
Dynamic modeling in renewable resource exploitation
No full textThis chapter reviews some fundamental models related to the exploitation of a renewable resource, an important topic when dealing with regional economics. The chapter starts by considering the growth models of an unexploited population and then introduces commercial harvesting. Still maintaining a dynamic perspective, an analysis of equilibrium situations is proposed for a natural resource under various market structures (monopoly, oligopoly and open access). The essential dynamic properties of these models are explained, as well as their main economic insights. Moreover, some key assumptions and tools of intertemporal optimal harvesting are recalled, thus providing an interesting application of the theory of optimal growth
Advancing contact of a 2D elastic curved beam indented by a rigid pin with clearance
No full textA two-dimensional analytical solution is presented for stresses and displacements in an elastic curved beam forming an incomplete ring in frictionless and unbonded contact with a rigid pin loaded by a point force and in the presence of clearance. The circular beam is modelled as an incomplete elastic thick ring, constrained at both ends and in a plane stress state. The stress and displacement fields within the beam are derived from a biharmonic Airy stress function, according to the Michell solution in polar coordinates. The mixed boundary value problem is reduced to a set of dual series equations and then to a non-homogeneous linear system of infinite equations, which is then solved by truncation. The non-linear relations between the applied load and the contact angle
or the pressure distribution are obtained by using an inverse method. The analytical results are compared with finite element predictions for a pin-lug connection and a reasonable agreement is
observed for several typical geometries. The peaks of contact pressure and von Mises equivalent stress and their location within the curved beam are evidenced
Experimental characterization of pull-in parameters for an electrostatically actuated cantilever
No full textMicro-electromechanical systems (MEMS) are a promising research frontier thanks to their multiple physical fields properties. In the field of microcantilever actuators, Radi et al., 2017, proposed an accurate analytical approach for estimating the pull-in characteristics of microcantilever actuators subject to electrostatic actuation. The present work assesses this previous analytical model via experimental tests with the use of a simple millimeter-scale device. The aim of the work is to measure the critical pull-in voltage and the deflection of an actuated cantilever beam for different configurations in order to validate the variation of the pull-in voltage with the geometrical parameters of the device provided by theoretical investigations. Preliminary tests show that the experimental pull-in voltage and deflection are in good agreement with the results provided by the analytical model. Specifically, the relative difference between experimental and analytical values of pull-in voltage is in the range between 0.7% and 10%
Elastodynamic local fields for a crack running in an orthotropic medium
No full textThe dynamic stress and displacement fields in the neighborhood of the tip of a crack propagating in an orthotropic medium are obtained. The approach deals with the methods of linear algebra to transform the equations of motion into a first-order elliptic system whose solution is sought under the assumption that the local displacement field may be represented under a scheme of separated variables. The analytical approach has enabled the distinction between two kinds of orthotropic materials for which explicit espressions of the near-tip stress fields are obtained. Some results are presented graphically also in order to compare them with the numerical solution given in a quoted reference
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