851 resultados para user study


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The population of English Language Learners (ELLs) globally has been increasing substantially every year. In the United States alone, adult ELLs are the fastest growing portion of learners in adult education programs (Yang, 2005). There is a significant need to improve the teaching of English to ELLs in the United States and other English-speaking dominant countries. However, for many ELLs, speaking, especially to Native English Speakers (NESs), causes considerable language anxiety, which in turn plays a vital role in hindering their language development and academic progress (Pichette, 2009; Woodrow, 2006). Task-based Language Teaching (TBLT), such as simulation activities, has long been viewed as an effective approach for second-language development. The current advances in technology and rapid emergence of Multi-User Virtual Environments (MUVEs) have provided an opportunity for educators to consider conducting simulations online for ELLs to practice speaking English to NESs. Yet to date, empirical research on the effects of MUVEs on ELLs’ language development and speaking is limited (Garcia-Ruiz, Edwards, & Aquino-Santos, 2007). This study used a true experimental treatment control group repeated measures design to compare the perceived speaking anxiety levels (as measured by an anxiety scale administered per simulation activity) of 11 ELLs (5 in the control group, 6 in the experimental group) when speaking to Native English Speakers (NESs) during 10 simulation activities. Simulations in the control group were done face-to-face, while those in the experimental group were done in the MUVE of Second Life. The results of the repeated measures ANOVA revealed after the Huynh-Feldt epsilon correction, demonstrated for both groups a significant decrease in anxiety levels over time from the first simulation to the tenth and final simulation. When comparing the two groups, the results revealed a statistically significant difference, with the experimental group demonstrating a greater anxiety reduction. These results suggests that language instructors should consider including face-to-face and MUVE simulations with ELLs paired with NESs as part of their language instruction. Future investigations should investigate the use of other multi-user virtual environments and/or measure other dimensions of the ELL/NES interactions.

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Physiological signals, which are controlled by the autonomic nervous system (ANS), could be used to detect the affective state of computer users and therefore find applications in medicine and engineering. The Pupil Diameter (PD) seems to provide a strong indication of the affective state, as found by previous research, but it has not been investigated fully yet. In this study, new approaches based on monitoring and processing the PD signal for off-line and on-line affective assessment (“relaxation” vs. “stress”) are proposed. Wavelet denoising and Kalman filtering methods are first used to remove abrupt changes in the raw Pupil Diameter (PD) signal. Then three features (PDmean, PDmax and PDWalsh) are extracted from the preprocessed PD signal for the affective state classification. In order to select more relevant and reliable physiological data for further analysis, two types of data selection methods are applied, which are based on the paired t-test and subject self-evaluation, respectively. In addition, five different kinds of the classifiers are implemented on the selected data, which achieve average accuracies up to 86.43% and 87.20%, respectively. Finally, the receiver operating characteristic (ROC) curve is utilized to investigate the discriminating potential of each individual feature by evaluation of the area under the ROC curve, which reaches values above 0.90. For the on-line affective assessment, a hard threshold is implemented first in order to remove the eye blinks from the PD signal and then a moving average window is utilized to obtain the representative value PDr for every one-second time interval of PD. There are three main steps for the on-line affective assessment algorithm, which are preparation, feature-based decision voting and affective determination. The final results show that the accuracies are 72.30% and 73.55% for the data subsets, which were respectively chosen using two types of data selection methods (paired t-test and subject self-evaluation). In order to further analyze the efficiency of affective recognition through the PD signal, the Galvanic Skin Response (GSR) was also monitored and processed. The highest affective assessment classification rate obtained from GSR processing is only 63.57% (based on the off-line processing algorithm). The overall results confirm that the PD signal should be considered as one of the most powerful physiological signals to involve in future automated real-time affective recognition systems, especially for detecting the “relaxation” vs. “stress” states.

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In recent decades, the national and international media contexts, in particular television media, significantly changed. The role that social networks, in particular Facebook, have taken as a content diffusion platform is unquestionable. Nowadays, traditional media (radio, newspaper, television) use the Web’s potential to distribute news content (Canelas, 2011). Currently, all TV news channels in Portugal have a website or a page on social networks. TV stations have increased communication channels with the public on digital platforms and study strategies that promote the participation and interaction with the news content (Cazajeira, 2015). The TV / Internet convergence will not only reach the content, but also the consumer, who becomes an interactive and participative audience. This reality imposes on journalism a continuous and updated news production system, dependent on a user being permanently connected to the Internet (Cazajeira, 2015). In fact, a report launched by an autonomous institution that has the function of supervising and regulating the media Portugal (ERC, 2015), confirms the relevance that social media has assumed in the publication and consumption of news. Social networks are recognised as one of the most important means for news media consultation, right after television, and the practice of sharing news is very common among consumers of online news in Portugal. Furthermore, when compared to other countries analysed by Reuters Institute (Newman, Levy, & Nielsen, 2015), Portuguese consumers are those who make the most comments to online news, preferring social networks to news sites. Considering the importance of new online platforms for journalism, this study aims to present a quantitative analysis of user participation on the Facebook pages of the three Portuguese TV news channels, specifically RTP3, SIC Notícias and TVI24, between 8 and 14 February 2016. To track this participation, the following parameters were used: the "like" button as a way to study the demonstration of publication interest; "sharing" of a particular element, be it a photo, a video or a text, on the user Timeline, the Timeline of a friend or by private message. This monitoring is important to understand the dissemination of news content; and the comments area. The number of comments will help understand the dynamics and the discussion that the publication has on the public. The results of 1063 posts indicate that of the analysed parameters - "Like", "Comment", and "Share" – the one with the greatest power of participation among the users of the pages of the three Portuguese TV news channels is the "Like" system, followed by "Share" and then "Comment". The theme that generates the most user participation with "Likes" and “Comments” parameters are "Science and Technology", “Education” and “Humorous/Satirical/Unusual”. Finally, the publications available end of the night (10pm-1am) has better participation rates.

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Objectives: To investigate patients' mobility and satisfaction with their lower-limb prosthetic or orthotic device and related service delivery in Sierra Leone; to compare groups of patients regarding type and level of assistive device, gender, area of residence, income; and to identify factors associated with satisfaction with the assistive device and service. Methods: A total of 139 patients answered questionnaires, including the Quebec User Evaluation of Satisfaction with Assistive Technology questionnaire (QUEST 2.0). Results: Eighty-six percent of assistive devices were in use, but half needed repair. Thirty-three percent of patients reported pain when using their assistive device. Patients had difficulties or could not walk at all on: uneven ground (65%); hills (75%); and stairs (66%). Patients were quite satisfied with their assistive device and the service (mean 3.7 out of 5 in QUEST), but reported 886 problems. Approximately half of the patients could not access services. In relation to mobility and service delivery, women, orthotic patients and patients using above-knee assistive devices had the poorest results. The general condition of the assistive device and patients' ability to walk on uneven ground were associated with satisfaction with the assistive devices and service. Conclusion: Patients reported high levels of mobility while using their device although they experienced pain and difficulties walking on challenging surfaces. Limitations in the effectiveness of assistive devices and limited access to follow-up services and repairs were issues desired to be addressed.

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Situational Awareness provides a user centric approach to security and privacy. The human factor is often recognised as the weakest link in security, therefore situational perception and risk awareness play a leading role in the adoption and implementation of security mechanisms. In this study we assess the understanding of security and privacy of users in possession of wearable devices. The findings demonstrate privacy complacency, as the majority of users trust the application and the wearable device manufacturer. Moreover the survey findings demonstrate a lack of understanding of security and privacy by the sample population. Finally the theoretical implications of the findings are discussed.

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The thermal decomposition of natural ammonium oxalate known as oxammite has been studied using a combination of high resolution thermogravimetry coupled to an evolved gas mass spectrometer and Raman spectroscopy coupled to a thermal stage. Three mass loss steps were found at 57, 175 and 188°C attributed to dehydration, ammonia evolution and carbon dioxide evolution respectively. Raman spectroscopy shows two bands at 3235 and 3030 cm-1 attributed to the OH stretching vibrations and three bands at 2995, 2900 and 2879 cm-1, attributed to the NH vibrational modes. The thermal degradation of oxammite may be followed by the loss of intensity of these bands. No intensity remains in the OH stretching bands at 100°C and the NH stretching bands show no intensity at 200°C. Multiple CO symmetric stretching bands are observed at 1473, 1454, 1447 and 1431cm-1, suggesting that the mineral oxammite is composed of a mixture of chemicals including ammonium oxalate dihydrate, ammonium oxalate monohydrate and anhydrous ammonium oxalate.

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The tridecameric Al-polymer [AlO4Al12(OH)24(H2O)12]7+ was prepared by forced hydrolysis of Al3+ up to an OH/Al molar ratio of 2.2. Under slow evaporation crystals were formed of Al13-nitrate. Upon addition of sulfate the tridecamer crystallised as the monoclinic Al13-sulfate. These crystals have been studied using near-infrared spectroscopy and compared to Al2(SO4)3.16H2O. Although the near-infrared spectra of the Al13-sulfate and nitrate are very similar indicating similar crystal structures, there are minor differences related to the strength with which the crystal water molecules are bonded to the salt groups. The interaction between crystal water and nitrate is stronger than with the sulfate as reflected by the shift of the crystal water band positions from 6213, 4874 and 4553 cm–1 for the Al13 sulfate towards 5925, 4848 and 4532 cm–1 for the nitrate. A reversed shift from 5079 and 5037 cm–1 for the sulfate towards 5238 and 5040 cm–1 for the nitrate for the water molecules in the Al13 indicate that the nitrate-Al13 bond is weakened due to the influence of the crystal water on the nitrate. The Al-OH bond in the Al13 complex is not influenced by changing the salt group due to the shielding by the water molecules of the Al13 complex.