Search results for "Online"

Silicon metasurfaces with tunable electromagnetic resonances for nonlinear optical conversion

2021

Dielectric metasurfaces sustain electromagnetic modes which can be exploited to enhance nonlinear frequency-conversion processes such as third-harmonic generation. In this work we employ electron-beam lithography to fabricate silicon metasurfaces supporting electromagnetic resonances with different quality factors (Q), ruled by the geometry. This allows to investigate the trade-off between resonant enhancement and matching the spectral bandwidth of the ultrafast excitation source. Both experiments and simulations indicate that higher values of Q do not a priori bring about a stronger third-harmonic generation, which correlates to the spectral overlap between the metasurface resonance and th…

Manipulating Light with Tunable Nanoantennas and Metasurfaces

2022

The extensive progress in nanofabrication techniques enabled innovative methods for molding light at the nanoscale. Subwavelength structured optical elements and, in general, metasurfaces and metamaterials achieved promising results in several research areas, such as holography, microscopy, sensing and nonlinear optics. Still, a demanding challenge is represented by the development of innovative devices with reconfigurable optical properties. Here, we review recent achievements in the field of tunable metasurface. After a brief general introduction about metasurfaces, we will discuss two different mechanisms to implement tunable properties of optical elements at the nanoscale. In particular…

Microwave response of bulk MgB2 samples of different granularity

2006

The microwave response of three high-density bulk MgB2 samples has been investigated in the linear and nonlinear regimes. The three samples, characterized by different mean size of grains, have been obtained by reactive infiltration of liquid Mg in powdered B preforms. The linear response has been studied by measuring the microwave surface impedance; the nonlinear response by detecting the power radiated by the sample at the second-harmonic frequency of the driving field. Our results suggest that bulk MgB2 prepared by the liquid Mg infiltration technique is particularly promising for manufacturing resonant cavities operating at microwave frequencies.

The interaction between consumers during the online customer journey

2017

The examination of the customer experience throughout customer journey is important to the business and academia. Creating a strong and positive experience within the customer journey will lead to better outcome by improving performance in customer travel at multiple touch points and through enhanced customer loyalty and word of mouth. There are a number of studies about interaction and online customer journey, but only a few research have explored social interactions between consumers during the online customer experience. The aim of this study is to explain how interaction between customers emerges during the online customer journey, which describes the overall customer experience from th…

The effect of prior information on musical preference rating how our musical preference is shaped by prior information in an online environment

2009

Min-Type Control Strategy of a DC-DC Synchronous Boost Converter

2019

International audience; This paper presents the analysis and design of a min-type strategy to control a synchronous boost converter in continuous conduction mode. The strategy uses a nonlinear switching surface to establish the change of topology in the converter and is analyzed by means of a sliding-mode control approach. Subsequently, the min-type strategy is modified by a hybrid control formulation, which introduces a hysteresis width and a dwell-time to obtain a finite switching frequency in the start-up and steady-state respectively. The hybrid control formulation is implemented digitally by means of a microprocessor which processes the samples of inductor current and capacitor voltage…

ON-LINE CONSTRUCTION OF A SMALL AUTOMATON FOR A FINITE SET OF WORDS

2012

In this paper we describe a "light" algorithm for the on-line construction of a small automaton recognising a finite set of words. The algorithm runs in linear time. We carried out good experimental results on real dictionaries, on biological sequences and on the sets of suffixes (resp. factors) of a set of words that shows how our automaton is near to the minimal one. For the suffixes of a text, we propose a modified construction that leads to an even smaller automaton. We moreover construct linear algorithms for the insertion and deletion of a word in a finite set, directly from the constructed automaton.

How do gender, Internet activity and learning beliefs predict sixth-grade students’ self-efficacy beliefs in and attitudes towards online inquiry?

2021

Today’s students search, evaluate and actively use Web information in their school assignments, that is, they conduct an online inquiry. This current survey study addresses sixth-grade students’ self-efficacy beliefs in and attitudes towards online inquiry, and to what extent free-time and school-related Internet activity, gender and learning beliefs explain these. The questionnaire was administered in 10 schools to 340 sixth-graders in Finland. Exploratory and confirmatory factor analyses revealed three elements of self-efficacy beliefs: self-efficacy in Web searching, the evaluation of sources and synthesising information. Furthermore, attitudes towards online inquiry loaded into two fact…

Virtual Exchange: Future-ready teaching of multiliteracies across borders and cultures

2020

Virtual exchange is an online form of internationalization at home. Students from different countries collaborate in small, international groups on tasks joined by a common theme. They combine their expertise when solving problems together. The teachers act as mentors, providing facilitation and support for the students during the virtual exchange. The student teams work independently by selecting the tools for the collaboration, allocating the tasks and creating the group’s final product. Virtual exchange is a transnational learning opportunity which enables students to learn and practice how to efficiently combine and make use of their digital, visual, critical, linguistic and intercultur…

Osallistujien motivaation muodostuminen ja hyödyntäminen online-yhteisössä

2017

Digitalisaation myötä yritykset ja brändit rakentavat online-yhteisöjä sitouttaakseen asiakkaita ja kuluttajia tiiviimmin omien sisältöjensä pariin. Taustalla on usein tavoite liiketoiminnan kasvusta, mutta myös kuluttajien sitouttamisesta ja aktiivisesta vuorovaikutuksesta heidän kanssaan. Tässä tutkimuksessa on tarkasteltu niitä tekijöitä, motiiveja, jotka saavat kuluttajan osallistumaan online-yhteisön toimintaan. Tutkimus on toteutettu aiempien tutkimusten tuottaman teoriatiedon sekä määrällisen aineiston avulla. Työn aineisto on kerätty kohdeorganisaation online-yhteisön käyttäjille suunnatulla kyselyllä, jossa on hyödynnetty aiempaa osallistumisen motiiveja mittaavaa tutkimusta sovelt…