Generation of scale-free assortative networks via Newman rewiring for simulation of diffusion phenomena

By collecting and expanding several numerical recipes developed in previous work, we implement an object-oriented Python code, based on the networkX library, for the realization of the configuration model and Newman rewiring. The software can be applied to any kind of network and "target" correlations, but it is tested with focus on scale-free networks and assortative correlations. For generating the degree sequence we use the method of "random hubs", which gives networks with minimal fluctuations. For the assortative rewiring we use the simple Vazquez-Weigt matrix as a test in the case of random networks; since it appears to be not effective in the case of scale-free networks we then turn to another recipe which generates matrices with decreasing off-diagonal elements. The rewiring procedure is important also at the theoretical level, in order to test which types of statistically acceptable correlations can actually be realized in concrete networks. From the applicative point of view, its main use is in the construction of correlated networks for the solution of dynamical or diffusion processes by analyzing the evolution of single nodes, i.e., beyond the Heterogeneous Mean Field approximation. As an example, we report on an application to the Bass diffusion model, with calculations of the time $t_{max}$ of the diffusion peak. The same networks can additionally be exported in environments for agent-based simulations like NetLogo.Comment: 19 pages, 8 figure

Sub-cycle dynamics in relativistic nanoplasma acceleration

The interaction of light with nanometer-sized solids provides the means of focusing optical radiation to sub-wavelength spatial scales with associated electric field enhancements offering new opportunities for multifaceted applications. We utilize collective effects in nanoplasmas with sub-two-cycle light pulses of extreme intensity to extend the waveform-dependent electron acceleration regime into the relativistic realm, by using 10(6) times higher intensity than previous works to date. Through irradiation of nanometric tungsten needles, we obtain multi-MeV energy electron bunches, whose energy and direction can be steered by the combined effect of the induced near-field and the laser field. We identified a two-step mechanism for the electron acceleration: (i) ejection within a sub-half-optical-cycle into the near-field from the target at >TVm(-1) acceleration fields, and (ii) subsequent acceleration in vacuum by the intense laser field. Our observations raise the prospect of isolating and controlling relativistic attosecond electron bunches, and pave the way for next generation electron and photon sources

The FLASHForward Facility at DESY

The FLASHForward project at DESY is a pioneering plasma-wakefield acceleration experiment that aims to produce, in a few centimetres of ionised hydrogen, beams with energy of order GeV that are of quality sufficient to be used in a free-electron laser. The plasma wave will be driven by high-current density electron beams from the FLASH linear accelerator and will explore both external and internal witness-beam injection techniques. The plasma is created by ionising a gas in a gas cell with a multi-TW laser system, which can also be used to provide optical diagnostics of the plasma and electron beams due to the <30 fs synchronisation between the laser and the driving electron beam. The operation parameters of the experiment are discussed, as well as the scientific program.Comment: 19 pages, 9 figure

Design in between offer and demand. The european phenomenon of design agencies

In the last 15 years a new actor is born within the supply-chain linking creativity, production and consumption. We are talking about those, public or private, national or trans-national, Agencies which mission is to discover new designers in order to promote and drive them into the market. At the peak of 20th century production positivism, design, like all so-called creative activities, fit easily in the well-oiled system of profits and consumption (at least until the economic and cultural crisis of the Seventies). However, professional placement today has become much more difficult because of our fluid social and production contexts, which force us to constantly redefine our knowledge and skills. At the same time, the explosion in the number of schools seems to have turned creativity into a sort of placebo-like magic potion that just about anybody can throw together. As a result, the number of newborn professionals has also exploded, and companies (the targets of all this creativity) see their arrival as a sort of attack of ‘foreign bodies’. And therefore they raise a higher and higher protective wall of fiduciary knowledge. Over the past 15 years, an interesting and representative phenomenon has grown up out of this unique condition. Indeed, a new link has been added to this ‘evolutionary chain’: promotional agencies for young designers. Whether national (and therefore subsidised by public funds) or true private and supranational service providers, there are now dozens of these agencies worldwide. These structures aren’t totally new, since their roots can be found in one of the key experiences of the very birth of industrial design: the Deutscher Werkbund founded in 1907. At the time, the organisation’s goal was to restore a virtuous link between creativity and production, a link that had been shattered by the first wave of industrialisation due to the impossibility of reconciling artisanal creative dynamics with industrial processes. Today, the goal of this type of organisation is to re-establish communication (which has broken down by information overload) between designers and companies, or more precisely, between supply and demand

Design Tactics. The design focus transition from the object to the subject

In the contemporary social-productive context the importance of an object’s technical and functional performance has now been lost because it has now become a message, a concept, and a meaning. Therefore, the relationship between design, production, and consumption is no longer a simple problem-solving activity but a comparison between specific cultural models. This has modified design activity, which now requires a different generative and creative action that passes from a known present to a possible future. The creative action has now become diffuse, and we can call it “design tactic”. Its aim is not an objective but a subjective quality perceived not only by the present society but, above all, by a future one. This signifies a passage from the creation of an object to the creation of a subject able to construct the meaning of human behaviour. According to this perspective; this paper proposes an interpretative model of the design / production / consumption relationship for an exchange of knowledge from companies to society by products. This paper is illustrated with an example of a project: the “On Air” project, conducted in collaboration with Elica, a leading company in the production of cooker-hoods

FROM ECO-NOMY TO ECO-PATHY. A DIFFERENT MODEL OF SUPPLY-CHAIN FOR DESIGN

Nowadays, within the productive, social and cultural scenario where Design acts, a new emergency is growing: a need to redefine the relationship between the different stakeholders of the supply-chain (from producers, to designers, to consumers). In particular, due to the process of globalization - which has completed his first maturation - we are assisting to the loss of the consolidated roles and the birth of new players; in fact, more then the ‘prophesied’ improvement of social economic and productive exchanges, there is an increasing gap between who is able to access to the global system and who remains in a more local condition. Is it possible to image a different geography to valorize also the local players? Could be Design a leverage for this? The project reported in this paper is an experimental research (according to the approach of action research) which investigates, analyses and tests a different model of relationship between the players of the design-production-consumption process

dire/fare/mangiare

Workshop con: Covo, CuocheperCaso, SlowFood, Yara Bitetti, Francesca Flore, Claudio Torcè Il design è concepito come stimolatore della percezione emozionale, a partire della cucina luogo deputato per raggiungere un benessere che risveglia e sollecita i sensi. Dalla vista che si abbandona ai colori di utensili ed ingredienti, all’olfatto e al gusto deliziati da odori e sapori, al tatto sollecitato dalla ruvidità o dalla morbidezza degli oggetti e delle pietanze

Small nature design. new design vision towards valuable consumption concepts.

The paper reports the research project "Small_Nature Design". It’s about the contemporary need of natural spaces, within the unhealthy urban habitats characterized by pollution, waste and physical density. This statement has been an important suggestion for this research, to define a different design approach able to overcome the futility of contemporary needs of societies and to understand the real desires. While designing small and big objects, we suggested new contexts and new uses, without any pretence to be the primary force behind social and individual well being. We considered as a starting point the definition of Design as “accelerator”, answering to human demands related to the environmental and social contexts. This definition takes a particular meaning within the current unstoppable progress, often perceived so intrusive to generate a double feeling of omnipotence and frustration. The omnipotence - to overcome our physical and cognitive limits - improves human quality of flexibility, which is able to adapt innovations according to our rhythms and goals. The frustration – to feel us victims of the technological hyper-stimulation – pushes people’s consciences towards more sustainable and human ways of life. Design to these conditions reacts on two levels: the first pushes towards the exploration of all possible interactions between man and technology (according to Design of Interaction); the second, on the opposite, pushes towards the resolution of more urgent failures of contemporary mature society (according to Design for Sustainability). But, within that practical relationship between men and objects called consumption, this disciplinary dichotomy becomes a mixed condition informed by a “fuzzy” logic. According to this, it has been defined a different design approach within those opposite approaches. The methodological result is a different design role, considered as “creative receiver” and able to redefine the relationship between consumption and production, while amplifying human activities according to a conscious innovation