Use In Communication Applications Research Articles

SSVEP detection assessment by combining visual stimuli paradigms and no-training detection methods.

Brain-Computer Interfaces (BCI) based on Steady-State Visually Evoked Potentials (SSVEP) have great potential for use in communication applications because of their relatively simple assembly and in some cases the possibility of bypassing the time-consuming training stage. However, among multiple factors, the efficient performance of this technology is highly dependent on the stimulation paradigm applied in combination with the SSVEP detection algorithm employed. This paper proposes the performance assessment of the classification of target events with respect to non-target events by applying four types of visual paradigms, rectangular modulated On-Off (OOR), sinusoidal modulated On-Off (OOS), rectangular modulated Checkerboard (CBR), and sinusoidal modulated Checkerboard (CBS), with three types of SSVEP detection methods, Canonical Correlation Analysis (CCA), Filter-Bank CCA (FBCCA), and Minimum Energy Combination (MEC). We set up an experimental protocol in which the four types of visual stimuli were presented randomly to twenty-seven participants and after acquiring their electroencephalographic responses to five stimulation frequencies (8.57, 10.909, 15, 20, and 24 Hz), the three detection methods were applied to the collected data. The results are conclusive, obtaining the best performance with the combination of either OOR or OOS visual stimulus and the FBCCA as a detection method, however, this finding contrasts with the opinion of almost half of the participants in terms of visual comfort, where the 51.9% of the subjects felt more comfortable and focused with CBR or CBS stimulation. Finally, the EEG recordings correspond to the SSVEP response of 27 subjects to four visual paradigms when selecting five items on a screen, which is useful in BCI navigation applications. The dataset is available to anyone interested in studying and evaluating signal processing and machine-learning algorithms for SSVEP-BCI systems.

The Influence of the COVID-19 Pandemic on the Use of Digital Technologies by Scientists: A Comparison Between Poland and Abroad

Purpose: Our research was performed to identify differences in the frequency of using digital technologies by scientists to support their research in the periods before, during, and after the COVID-19 pandemic Design/methodology/approach: A survey questionnaire was used and data were collected from 467 scientists from Poland and abroad, which were statistically analyzed. The non-parametric Kruskal–Wallis test was applied to reveal the differences in the frequency of digital technologies use between scientists in Poland and abroad in three periods (before, during, and after the COVID-19 pandemic). The non-parametric Friedman rank test and the post-hoc Conover test with Benjamini-Hochberg adjustment were used to assess the significant differences between three paired periods: before-during, before-after, and during-after the COVID-19 pandemic. For these periods, the association between the use of digital technologies and the types of research (basic or applied) conducted by scientists in Poland and abroad was also measured using Spearman’s rank correlation. Findings: Scientists from Poland and abroad differed in the use of all digital technologies before and after the COVID-19 pandemic. During the pandemic, the differences concerned only social media, owing to a similar increase in the use of both communication applications and e-learning platforms. The results demonstrated that there was a weak positive correlation between the use of all digital technologies and applied research by both groups of scientists for all paired periods. In Poland in particular, our research has confirmed a positive correlation between the use of communication applications and social media and basic research for two paired periods: before-during and during-after the pandemic. Research limitation/implications: The limitations of this study were primarily related to the sample size, which did not allow the results to be generalized to the entire population. Another limitation was that all scientists from outside Poland were assigned to one group, without division into countries or regions of the world. This, however, enabled the research scope to be narrowed and resulted in stressing the differences between Poland and the rest of the world. A further limitation that may affect the research results is the adopted 5-point Likert scale, which determines the possibility of making an analysis. Originality/value: This research contributes to knowledge about the adaptation of scientists in Poland and abroad to new conditions resulting from the COVID-19 pandemic regarding the frequency of digital technology use in basic and applied research. The significant differences found in the frequency of digital technology use between the three paired periods (before-during, before-after, and during-after the pandemic) have the potential to encourage research into their permanence.

Exploring user perceptions of deletion in mobile instant messaging applications

Abstract Contemporary mobile messaging provides rich text and multimedia functionality leaving detailed trails of sensitive user information that can span long periods of time. Allowing users to manage the privacy implications both on the sender and the receiver side can help to increase confidence in the use of communication applications. In October 2017, one of the mobile messengers with the largest user base, WhatsApp, introduced a feature to delete past messages from communication, both from the sender’s and the recipient’s devices. In this article, we compare the deletion features of 17 popular messaging applications. Implementations of these features widely differ across the applications we examined. We further report on a study with 125 participants conducted in a between-subjects design. We explore users’ preferences for deleting mobile messages, and we investigate how well they comprehend this functionality as implemented in popular messaging applications. We found statistically significant differences in users’ understanding of message deletion between our three test conditions, comprising WhatsApp, Facebook Messenger, and Skype. Eighty percent of participants in the WhatsApp condition could correctly assess the effects of deleting messages, compared to only 49% in the Skype condition. In addition, we provide insights into qualitative feedback received from our participants. Our findings indicate that message deletion is seen as a potentially useful feature that users may be able to use in different ways, including editing messages. Furthermore, users can more precisely estimate the capabilities of a deletion function when its effects are transparently explained in the application’s user interface.

Coplanar Waveguide Filter using Stub Resonators for Ultra Wide Band Applications

The paper presents a compact coplanar waveguide filter employing stub resonators for ultra wide band applications. A cascade connection of series and shunt stubs quarter wavelength long is used for achieving bandpass characteristics. The performance requirement of the filter decides the number of cascaded sections. The filter has reduced insertion loss in its passband and good attenuation in lower and upper stopbands. The flat group delay in the passband ensures its use in communication applications. Measured frequency response of the fabricated prototype shows good agreement with simulated response.

Accuracy of 2-Dimensional Object Location Estimation Using Leaky Coaxial Cables

The improvement of position estimation accuracy is a very important factor in various radar applications. This paper focuses on two-dimensional (2-D) location estimation in radar surveillance using leaky coaxial cables. A leaky coaxial cable is a kind of antenna and has recently attracted attention as a powerful tool for vehicle detection and as an intrusion detection sensor for perimeter security. We derive the Cramér-Rao bound (CRB) for a leaky coaxial cable sensing application and introduce the CRB ellipsoid to evaluate the accuracy of the 2-D location estimation of an object. The diameter and angle of a CRB ellipsoid indicates its error distribution. A leaky coaxial cable has an outer conductor with periodic slots. Its slot pattern determines the radiation characteristics such as the beam angle and harmonic radiation. We focus on the slot pattern to improve the estimation accuracy. Numerical analyses show that a slot pattern generating multi-beams improves the accuracy while single radiation is preferred for general use in communication applications.