159 research outputs found
Recommended from our members
Web navigation for individuals with dyslexia: An exploratory study
In this paper, we present an exploratory study of the web navigation experiences of dyslexic users. Findings indicate that dyslexics exhibit distinctive web navigation behaviour and preferences. We believe that the outcomes of this study add to our understanding of the particular needs of this web user population and have implications for the design of effective navigation structures
A Human-centric AI-driven Framework for Exploring Large and Complex Datasets
Human-Centered Artificial Intelligence (HCAI) is a new frontier of research at the intersection between HCI and AI. It fosters an innovative vision of human-centred intelligent systems, which are systems that take advantage of computer features, such as powerful algorithms, big data management, advanced sensors and that are useful and usable for people, providing high levels of automation and enabling high levels of human control. This position paper presents our ongoing research aiming to extend the HCAI framework for better supporting designers in creating AI-based systems
Experimental evidence of rainbow trapping and Bloch oscillations of torsional waves in chirped metallic beams
[EN] The Bloch oscillations (BO) and the rainbow trapping (RT) are two apparently unrelated phenomena, the former arising in solid state physics and the latter in metamaterials. A Bloch oscillation, on the one hand, is a counter-intuitive effect in which electrons start to oscillate in a crystalline structure when a static electric field is applied. This effect has been observed not only in solid state physics but also in optical and acoustical structured systems since a static electric field can be mimicked by a chirped structure. The RT, on the other hand, is a phenomenon in which the speed of a wave packet is slowed down in a dielectric structure; different colors then arrive to different depths within the structure thus separating the colors also in time. Here we show experimentally the emergence of both phenomena studying the propagation of torsional waves in chirped metallic beams. Experiments are performed in three aluminum beams in which different structures were machined: one periodic and two chirped. For the smaller value of the chirping parameter the wave packets, with different central frequencies, are back-scattered at different positions inside the corrugated beam; the packets with higher central frequencies being the ones with larger penetration depths. This behavior represents the mechanical analogue of the rainbow trapping effect. This phenomenon is the precursor of the mechanical Bloch oscillations, which are here demonstrated for a larger value of the chirping parameter. It is observed that the oscillatory behavior observed at small values of the chirp parameter is rectified according to the penetration length of the wave packet.Work partially supported by DGAPA-UNAM under projects PAPIIT IN103115 and IN109318 and by CONACYT project 284096. A.A.L. acknowledges CONACYT for the support granted to pursue his Ph.D. studies. G. Baez received CONACYT's financial support. RAMS received support from DGAPA-UNAM under program PASPA. We thank M. Martinez, A. Martinez, V. Dominguez-Rocha, E. Flores and E. Sadurni for invaluable comments. F.C., A.C. and J.S-D. acknowledge the support by the Ministerio de Economa y Competitividad of the Spanish government, and the European Union FEDER through project TEC2014-53088-C3-1-R.Arreola-Lucas, A.; Baez, G.; Cervera Moreno, FS.; Climente AlarcĂłn, A.; Mendez-Sanchez, R.; SĂĄnchez-Dehesa Moreno-Cid, J. (2019). Experimental evidence of rainbow trapping and Bloch oscillations of torsional waves in chirped metallic beams. Scientific Reports. 9:1860-1872. https://doi.org/10.1038/s41598-018-37842-7S186018729Ascroft, N. W. & Mermin, N. D. Solid State Physics (Hold, Reinhart & Winston, 1972).Kadic, M., Buckmann, T., Schittny, R. & Wegener, M. Metamaterials beyond electromagnetism. Rep. Prog. Phys. 76, 126501 (2013).Cummer, S. A., Christensen, J. & AlĂč, A. Controlling sound with acoustic metamaterials. Nat. Rev. Mat. 1, 16001 (2016).Tsakmakidis, K. L., Boarman, A. D. & Hess, O. Trapped rainbow storage of light in metamaterials. Nature 450, 397â401 (2007).Kathryn, H. et al. Designing perturbative metamaterials from discrete models. Nat. Mat. 17, 323â328 (2018).de Lima, M. M. Jr., Kosevich, Y. A., Santos, P. V. & Cantarero, A. Surface acoustic Bloch oscillations and Wannier-Stark ladders and Landau-Zenner tunneling in a solid. Phys. Rev. Lett. 104, 165502, https://doi.org/10.1103/PhysRevLett.104.165502 (2010).Tian, Z. & Yu, L. Rainbow trapping of ultrasonic guided waves in chirped phononic crystal plates. Sci. Rep. 7, 40004, https://doi.org/10.1038/srep40004 (2017).Waschke, C. et al. Coherent submillimeter-wave emission from bloch oscillations in a semiconductor superlattice. Phys. Rev. Lett. 70, 3319â3322, https://doi.org/10.1103/PhysRevLett.70.3319 (1993).Sapienza, R. et al. Optical analogue of electronic Bloch oscillations. Phys. Rev. Lett. 91, 263902 (2014).Morandotti, R., Peschel, U., Aitchison, J. S., S., E. H. & Silberberg, Y. Experimental observation of linear and nonlinear optical Bloch oscillations. Phys. Rev. Lett. 83, 4756 (1999).Battestti, R. et al. Bloch oscillations of ultracould atoms: a tool for a metrological determination of hâ/âmRb. Phys. Rev. Lett. 92, 253001, https://doi.org/10.1103/PhysRevLett.92.253001 (2007).Sanchis-Alepuz, H., Kosevich, Y. & SĂĄnchez-Dehesa, J. Acoustic analogue of electronic Bloch oscillations. Phys. Rev. Lett. 98, 134301, https://doi.org/10.1103/PhysRevLett.104.197402 (2007).Lanzilotti-Kimura, N. D. et al. Bloch oscillations of THz acoustic phonons in coupled nanocavity structures. Phys. Rev. Lett. 104, 197402, https://doi.org/10.1103/PhysRevLett.104.197402 (2010).FloĂ, J., Kamalov, A., Averbukh, I. S. & H., B. P. Observation of Bloch oscillations in molecular rotation. Phys. Rev. Lett. 115, 203002, https://doi.org/10.1103/PhysRevLett.115.203002 (2015).Gan, Q., Ding, Y. J. & Bartoli, F. Trapping and releasing at telecommunication wavelengths. Phys. Rev. Lett. 102, 056801, https://doi.org/10.1103/PhysRevLett.102.056801 (2009).Park, J., Boarman, A. D. & Hess, O. Trapping light in plasmonic waveguides. Opt. Express 18, 598â623, https://doi.org/10.1364/OE.18.000598 (2010).Zhao, D., Li, Y. & Zhu, X. Trapped rainbow effect in visible light left-handed heterostructures. Appl. Phys. Lett. 95, 071111, https://doi.org/10.1063/1.3211867 (2009).Smolyaninova, V. N., Smolyaninov, I. I., Kildishev, A. V. & Shalaev, V. Experimental observation of the trapped rainbow. Appl. Phys. Lett. 96, 211121, https://doi.org/10.1063/1.3442501 (2010).Ni, X. et al. Acoustic rainbow trapping by coiling up space. Sci. Rep. 4, 7038, https://doi.org/10.1038/srep07038 (2014).Zhu, J. et al. Acoustic rainbow trapping. Sci. Rep. 3, 1728, https://doi.org/10.1038/srep01728 (2013).Romero-GarcĂa, V., PicĂł, R., Cebrecos, A., SĂĄnchez-Morcillo, V. J. & Staliunas, K. Enhancement of sound in chirped sonic cristals. Appl. Phys. Lett. 102, 091906, https://doi.org/10.1063/1.4793575 (2013).Cebrecos, A. et al. Enhancement of sound by soft reflections in exponentially chirped cristals. AIP Adv. 4, 124402, https://doi.org/10.1063/1.4902508 (2014).Zhao, D., Li, Y. & Zhu, X. Broadband lamb wave trapping in cellular metamaterial plates with multiple local resonances. Sci. Rep. 5, 9376, https://doi.org/10.1038/srep09376 (2015).Gutierrez, L. et al. Wannier-stark ladders in one-dimensional elastic systems. Phys. Rev. Lett. 97, 114301, https://doi.org/10.1103/PhysRevLett.97.114301 (2006).Morales, A., Flores, J., Gutierrez, L. & MĂ©ndez-SĂĄnchez, R. A. Compressional and torsional wave amplitudes in rods with periodic structures. J. Acoust. Soc. Am. 112, 1961, https://doi.org/10.1121/1.1509431 (2002).Arreola-Lucas, A. et al. Bloch oscillations in mechanical vibrations. PIERS proceedings. (to appear).Graff, K. F. Wave Motion in Elastic Solids (Dover, 1991)
The Usability of E-learning Platforms in Higher Education: A Systematic Mapping Study
The use of e-learning in higher education has increased significantly in recent years, which has led to several studies being conducted to investigate the usability of the platforms that support it. A variety of different usability evaluation methods and attributes have been used, and it has therefore become important to start reviewing this work in a systematic way to determine how the field has developed in the last 15 years. This paper describes a systematic mapping study that performed searches on five electronic libraries to identify usability issues and methods that have been used to evaluate e-learning platforms. Sixty-one papers were selected and analysed, with the majority of studies using a simple research design reliant on questionnaires. The usability attributes measured were mostly related to effectiveness, satisfaction, efficiency, and perceived ease of use. Furthermore, several research gaps have been identified and recommendations have been made for further work in the area of the usability of online learning
Privacy Design Strategies and the GDPR: A Systematic Literature Review
Article 25 of the GDPR states that data collection, processing and management measures should be implemented following táčhe privacy by design and privacy by default paradigms. This paper presents a systematic literature review to identify useful guidelines to support the development of GDPR-compliant software. Selected papers are categorized under 8 different data-oriented and process-oriented strategies and their contributions are reported. Future activities will highlight the HCI communityâs attitude towards these new technical and organizational approaches in order to bridge the identified gaps and shortcomings
Use of large multi-touch screens for informal learning
The advent on the market of multi-touch devices has prompted studies that investigate the use of such devices in learning domain, demonstrating that games are an effective way of exploiting these new technologies that allow pupils to achieve informal learning and foster collaboration during their educational activities. We defined an educational format that combines traditional learning performed at school with educational multimedia games implemented on a multi-touch screen, set up vertically. A field study showed the effectiveness of this educational format, supporting the use of applications on the multi-touch display to help pupils consolidating the acquired knowledge. This paper reports a complementary study that analyses pupilsâ reactions to the use of a traditional desktop as compared with the use of the multi-touch screen. Results provided further evidence that pupils enjoy interacting with the multi-touch screen, because it allows them to collaborate and to use their hands, directly moving objects about on the screen
Metamorphic data sources: A user-centric paradigm to consume linked data in interactive workspaces
In the last years, the debate about the success or failure of Linked Data (LD) has been growing. Despite the ever-increasing number of available ontologies and LD datasets, there is still a limited number of applications to let people benefit from using this huge amount of data. Some evident problems relate to the limited opportunities offered to the end users, i.e., people without skills in computer programming, to access, navigate and visualize LD. Tools supporting such tasks typically do not consider the end usersâ needs; even when they provide abstraction mechanisms to avoid programming, they do not properly hide the complexity of getting oriented into the plethora of available resources. Thus, they end up to be inadequate to real daily scenarios. In this paper, we propose an approach that enables end users to create visually entry points, which we call Metamorphic Data-Sources (MDSs), to query and visualize the LD without requiring any prior knowledge of semantic Web or visualization technologies. Through the MDS visual paradigm, end users can tailor ad-hoc data sources to retrieve information on topics they are interested in. The MDS creation process is also driven by a quality model that further helps users select LD elements potentially free of data quality problems. The paper also reports on the results of a user study that we conducted to assess the validity of the MDS paradigm with respect to the user needs
A Circular Visualization of People's Activities in Distributed Teams
When working in distributed teams, it is very important to be aware of the activities of all members, since it provides hints about when they might be available for collaboration. We propose a novel visualization technique that combines several representations to show the daily patterns of team members' activities. It uses a 24 hours circular display to facilitate international collaboration across time zones. Current calendar information can be compared to the typical patterns and reveal likely availability. User studies evaluating the tool that implements the proposed technique are reported and discussed
User-defined semantics for the design of IoT systems enabling smart interactive experiences
Automation in computing systems has always been considered a valuable solution to unburden the user. Internet of Things (IoT) technology best suits automation in different domains, such as home automation, retail, industry, and transportation, to name but a few. While these domains are strongly characterized by implicit user interaction, more recently, automation has been adopted also for the provision of interactive and immersive experiences that actively involve the users. IoT technology thus becomes the key for Smart Interactive Experiences (SIEs), i.e., immersive automated experiences created by orchestrating different devices to enable smart environments to fluidly react to the final usersâ behavior. There are domains, e.g., cultural heritage, where these systems and the SIEs can support and provide several benefits. However, experts of such domains, while intrigued by the opportunity to induce SIEs, are facing tough challenges in their everyday work activities when they are required to automate and orchestrate IoT devices without the necessary coding skills. This paper presents a design approach that tries to overcome these difficulties thanks to the adoption of ontologies for defining Event-Condition-Action rules. More specifically, the approach enables domain experts to identify and specify properties of IoT devices through a user-defined semantics that, being closer to the domain expertsâ background, facilitates them in automating the IoT devices behavior. We also present a study comparing three different interaction paradigms conceived to support the specification of user-defined semantics through a âtransparentâ use of ontologies. Based on the results of this study, we work out some lessons learned on how the proposed paradigms help domain experts express their semantics, which in turn facilitates the creation of interactive applications enabling SIEs
- âŠ