scholarly journals The Dry Revolution: Evaluation of Three Different EEG Dry Electrode Types in Terms of Signal Spectral Features, Mental States Classification and Usability

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1365 ◽  
Author(s):  
Gianluca Di Flumeri ◽  
Pietro Aricò ◽  
Gianluca Borghini ◽  
Nicolina Sciaraffa ◽  
Antonello Di Florio ◽  
...  

One century after the first recording of human electroencephalographic (EEG) signals, EEG has become one of the most used neuroimaging techniques. The medical devices industry is now able to produce small and reliable EEG systems, enabling a wide variety of applications also with no-clinical aims, providing a powerful tool to neuroscientific research. However, these systems still suffer from a critical limitation, consisting in the use of wet electrodes, that are uncomfortable and require expertise to install and time from the user. In this context, dozens of different concepts of EEG dry electrodes have been recently developed, and there is the common opinion that they are reaching traditional wet electrodes quality standards. However, although many papers have tried to validate them in terms of signal quality and usability, a comprehensive comparison of different dry electrode types from multiple points of view is still missing. The present work proposes a comparison of three different dry electrode types, selected among the main solutions at present, against wet electrodes, taking into account several aspects, both in terms of signal quality and usability. In particular, the three types consisted in gold-coated single pin, multiple pins and solid-gel electrodes. The results confirmed the great standards achieved by dry electrode industry, since it was possible to obtain results comparable to wet electrodes in terms of signals spectra and mental states classification, but at the same time drastically reducing the time of montage and enhancing the comfort. In particular, multiple-pins and solid-gel electrodes overcome gold-coated single-pin-based ones in terms of comfort.

2020 ◽  
Vol 6 (3) ◽  
pp. 139-142
Author(s):  
Jens Haueisen ◽  
Patrique Fiedler ◽  
Anna Bernhardt ◽  
Ricardo Gonçalves ◽  
Carlos Fonseca

AbstractMonitoring brain activity at home using electroencephalography (EEG) is an increasing trend for both medical and non-medical applications. Gel-based electrodes are not suitable due to the gel application requiring extensive preparation and cleaning support for the patient or user. Dry electrodes can be applied without prior preparation by the patient or user. We investigate and compare two dry electrode headbands for EEG acquisition: a novel hybrid dual-textile headband comprising multipin and multiwave electrodes and a neoprene-based headband comprising hydrogel and spidershaped electrodes. We compare the headbands and electrodes in terms of electrode-skin impedance, comfort, electrode offset potential and EEG signal quality. We did not observe considerable differences in the power spectral density of EEG recordings. However, the hydrogel electrodes showed considerably increased impedances and offset potentials, limiting their compatibility with many EEG amplifiers. The hydrogel and spider-shaped electrodes required increased adduction, resulting in a lower wearing comfort throughout the application time compared to the novel headband comprising multipin and multiwave electrodes.


Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4298
Author(s):  
Alessandra Galli ◽  
Elisabetta Peri ◽  
Yijing Zhang ◽  
Rik Vullings ◽  
Myrthe van der Ven ◽  
...  

Multi-channel measurements from the maternal abdomen acquired by means of dry electrodes can be employed to promote long-term monitoring of fetal heart rate (fHR). The signals acquired with this type of electrode have a lower signal-to-noise ratio and different artifacts compared to signals acquired with conventional wet electrodes. Therefore, starting from the benchmark algorithm with the best performance for fHR estimation proposed by Varanini et al., we propose a new method specifically designed to remove artifacts typical of dry-electrode recordings. To test the algorithm, experimental textile electrodes were employed that produce artifacts typical of dry and capacitive electrodes. The proposed solution is based on a hybrid (hardware and software) pre-processing step designed specifically to remove the disturbing component typical of signals acquired with these electrodes (triboelectricity artifacts and amplitude modulations). The following main processing steps consist of the removal of the maternal ECG by blind source separation, the enhancement of the fetal ECG and identification of the fetal QRS complexes. Main processing is designed to be robust to the high-amplitude motion artifacts that corrupt the acquisition. The obtained denoising system was compared with the benchmark algorithm both on semi-simulated and on real data. The performance, quantified by means of sensitivity, F1-score and root-mean-square error metrics, outperforms the performance obtained with the original method available in the literature. This result proves that the design of a dedicated processing system based on the signal characteristics is necessary for reliable and accurate estimation of the fHR using dry, textile electrodes.


PMLA ◽  
1912 ◽  
Vol 27 (2) ◽  
pp. 117-141
Author(s):  
Robert Adger Law
Keyword(s):  

The chief source of Shakespeare's tragedy of Richard the Third has long been acknowledged to be either Hall's or Holinshed's prose Chronicle. In addition, some echoes have been discovered in it of the Latin tragedy, Richardus Tertius, of the anonymous English True Tragedie of Richard the Third, and of Marlowe's play, Edward the Second. But for one of the longest and most impressive scenes in Shakespeare's drama, that in which Clarence in prison meets his death at the hands of two ruffians hired for the deed by his brother, the Duke of Gloucester, no source is generally known. For the basis of the entire scene, Hall's Chronicle, which is so close akin to most situations in the play, contains of Clarence's death merely the statement that “attainted was he by parliament and iudged to death, and there vpon hastely drowned in a butte of malmesey within the towre of London.” Mr. P. A. Daniel expresses the common opinion of Shakespearian scholars to-day in saying, “Shakespeare seems to have been indebted to his own imagination only, for the scene of Clarence in prison, his beautiful narrative of his dream, and the less happy dialogue of the murderers.”


2015 ◽  
Vol 5 ◽  
pp. 357-368
Author(s):  
Hanna Zalewska-Jura

This article discusses the relatively unknown poetry of Bessarion, the future Cardinal. The author argues with a negative opinion of F. M. Pontani concerning the three epicedia on the death of Theodora Comnena. The author analyses the composition, artistic means of expression and intertextual links in order to revise the common opinion in the subject and to prove the presence of literary values in the mentioned poems.


2017 ◽  
pp. 162-167 ◽  
Author(s):  
I. N. Zakharova ◽  
I. M. Osmanov ◽  
E. B. Mumladze ◽  
E. B. Machneva ◽  
E. V. Tambieva ◽  
...  

2001 ◽  
Vol 22 (1) ◽  
Author(s):  
Douglas Walton

This article concerns the structure of defeasible arguments like: 'If Bob has red spots, Bob has the measles; Bob has red spots; therefore Bob has the measles.' The issue is whether such arguments have the form of modus ponens or not. Either way there is a problem. If they don't have the form of modus ponens, the common opinion to the contrary taught in leading logic textbooks is wrong. But if they do have the form of modus ponens, doubts are raised about the conventional dogma that all arguments having the form of modus ponens are deductively valid. By carefully examining arguments on both sides of the issue, reasonable doubts are raised about the view that all arguments having a modus ponens form are valid.


2017 ◽  
Vol 3 (1) ◽  
pp. 43
Author(s):  
Zuzanna Służewska

THE CONTRACT OF PARTNERSHIP AS A BASE OF IN SOLIDUM LIABILITY IN ROMAN LAWSummary In the modern civil law joint and several liability of partners in a partnership is a rule rather than an exception. According to the common opinion this concept did not originate in the Roman law but was first invented in the medieval times by glossators and commentators. The Roman partnership created only a private relation between partners (who, due to a conclusion of that contract were reciprocally obliged to act together in accordance with a good faith in order to conduct common business and to divide profits and bear losses in proportion to their respective shares) and its conclusion did not affect their liability against third parties. The partners had no right to bind themselves contractually to any third parties, unless they all acted jointly (in this case, however, their joint representation was derived from their expressed declarations and not the existence of a contract o f partnership). Thus, any commitment made by an individual partner, even if made within the scope of a partnership having obtained other partners’ consent, was treated as a personal debt of this partner and the remaining partners were not liable against his contractor. Then, of course, the partner who made a commitment (acting within the partnership’s business) could claim a part of what he had paid to a third party from other partners in proportion to their respective shares in the common enterprise.Such a solution was necessary because of the purely consensual character o f the Roman partnership and the lack of any formal procedure of its conclusion and dissolution. The existence of that contract could not affect the model of the external liability of partners, because it would be too risky for third parties, which had no possibility to make sure if a contract of partnership between some persons had been actually concluded or not. Thus, the role of a contract of partnership in the Roman law was only limited to determine a mutual liability o f partners, to specify their respective rights and obligations and to define the scope of their liability against other partners.There are only a few written sources concerning so called specific kinds of partnership characterized by untypical joint and several responsibility of partners. Moreover these texts are not very clear and are difficult to interpret, so the issue of specific kinds of a partnership is a matter of doubts among Romanists. Some authors even believe that the specific types of partnership did not exist in the Roman law at all.It should be firstly observed that the texts regarding a contract of partnership itself (the texts included in the title pro socio of Justinian’ Digest) did not raise the question of the external liability of partners because they were devoted to internal settlement o f accounts within sociu Thus, taking into account only these texts one cannot ascertain that a conclusion of a contract of partnership could not affect in any way the model of the partners’ liability against third parties.Secondly, the other texts concerning the regulation of conducting an economic activity in the Roman law (actio institoria, actio exercitoria and actio de peculio) present some regularity in an introduction of joint and several liability of debtors.On the one hand that model of the liability was introduced in situations in which protecting safety of trade required that the creditor be able to claim a whole amount o f the debt from one person only.On the other hand this model of liability could be introduced only in these cases in which some internal relation existed between several debtors. On the grounds of such relations the debtor who satisfied in full the creditor’s claim could sue other debtors in order to recover their respective parts in the debt. In the Roman law that internal relation that guaranteed the possibility of a recourse could be either a joint-ownership or a partnership.Having considered that, one may say that the texts concerning specific kinds o f partnership do not prove existence of any special type of societas. These sources regard only the situations when a joint and several liability between several debtors was introduced because it was justified by the circumstances: that is the necessity to protect the safety of trade on one hand and the existence of the contract of partnership that guaranteed a possibility to realize the recourse, on the other.In conclusion one may say that although a closing of a contract of partnership did not create a joint and several liability of partners, in some cases its existence was decisive for introducing this model of liability since it guaranteed to every party a possibility to act against the others to obtain the recourse. Thus, Roman jurisprudence made an important step towards the future introduction o f joint and several liability of partners as a rule of a civil law.


Author(s):  
V.V. Kotelevskaya

The article explores the typological principles and genesis of narrative thinking of Thomas Bernhard (1931-1989). It reveals the paradoxical nature of his writing, which combines, on the one hand, archetypal structures, implied ‘genre memory’, and on the other hand, a unique, innovative style. Bernhard’s constructive principle is repetition, which allows the embodiment of the idea of «eternal return» (Eliade) throughout the poetical structure, whether it is a sacred event of a myth or an «obsessive repetition» (Freud) of the traumatic memories of the protagonist or the narrator. The fragmented world is under constant reorganizing with the help of Bernhard’s polyphonic writing, which finds itself mostly in the imitation of the non-figurative, purely expressive, self-referential «art of fugue» (Bach), oriented to the cyclic, rather than linear-historical concept of time. In contrast to the literary interpretation of the «polyphonic novel» (Bakhtin) with its coexistence of multiple points of view, our attention is shifted to the musicological interpretation of the fugue’s polyphony as the embodied idea of the continuity of time, the closeness and infinity of the divine universe.


2015 ◽  
Vol 117 (11) ◽  
pp. 1-32
Author(s):  
Charles Munter ◽  
Mary Kay Stein ◽  
Margaret S. Smith

Background/Context Which ideas should be included in the K–12 curriculum, how they are learned, and how they should be taught have been debated for decades in multiple subjects. In this article, we offer mathematics as a case in point of how new standards-related policies may offer an opportunity for reassessment and clarification of such debates. Purpose/Objective Our goal was to specify instructional models associated with terms such as “reform” and “traditional”—which, in this article, we refer to as “dialogic” and “direct”—in terms of perspectives on what it means to know mathematics, how students learn mathematics, and how mathematics should be taught. Research Design In the spirit of “adversarial collaboration,” we hosted a series of semi-structured discussions among nationally recognized experts who hold opposing points of view on mathematics teaching and/or learning. During those discussions, the recent consensus regarding what students should learn—as represented by the Common Core State Standards for Mathematics (CCSSM)—was taken as a common goal, and additional areas of agreement and disagreement were identified and discussed. The goal was not to reach consensus but to invite representatives of different perspectives to clarify and come to agreement on how they disagree. Findings/Results We present two instructional models that were specified and refined over the course of those discussions and describe nine key areas that distinguish the two models: (a) the importance and role of talk; (b) the importance and role of group work; (c) the sequencing of mathematical topics; (d) the nature and ordering of mathematical instructional tasks; (e) the nature, timing, source, and purpose of feedback; (f) the emphasis on creativity (i.e., authoring one's own learning; mathematizing subject matter from reality); (g) the purpose of diagnosing student thinking; (h) the introduction and role of definitions; and (i) the nature and role of representations. Additionally, we elaborate a more nuanced description of the ongoing debate, as it pertains to particular sources of difference in perspective. Conclusions/Recommendations With this article, we hope to advance ongoing debates in two ways: (a) discrediting false assumptions and oversimplified conceptions of the “other side's” arguments (which can obscure both the real differences and real similarities between different models of instruction), and (b) framing the debates in a manner that allows for more thoughtful empirical investigation oriented to understanding learning in the discipline.


Author(s):  
Giuseppe Carignani

The airframe revolution was the greatest development in aviation history after the Wright brothers, marking the advent of the modern dominant design in aerostructures, namely, the all-metal monoplane, which is still largely in existence. Therefore, the importance of the airframe revolution can hardly be overestimated. Nonetheless, its origin remains poorly understood. The common opinion is that the development of new materials and scientific advancements were the drivers of the transition. However, the historical record tells a different story. This chapter demonstrates that an event of ‘modular exaptation’, namely, the design of the Fokker D.VIII fighter, initiated the revolution in 1918, several years before its recognized inception. This evolutionary interpretation reconciles the gradualist Darwinian vision with the discontinuous character of radical innovation. The Fokker D.VIII case study suggests that detecting technological exaptations ex ante is possible and can provide firms with sustained competitive advantage.


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