Non-binary m-sequences for more comfortable brain–computer interfaces based on c-VEPs

Producción CientíficaCode-modulated visual evoked potentials (c-VEPs) have marked a milestone in the scientific literature due to their ability to achieve reliable, high-speed brain–computer interfaces (BCIs) for communication and control. Generally, these expert systems rely on encoding each command with shifted versions of binary pseudorandom sequences, i.e., flashing black and white targets according to the shifted code. Despite the excellent results in terms of accuracy and selection time, these high-contrast stimuli cause eyestrain for some users. In this work, we propose the use of non-binary p-ary m-sequences, whose levels are encoded with different shades of gray, as a more pleasant alternative than traditional binary codes. The performance and visual fatigue of these p-ary m-sequences, as well as their ability to provide reliable c-VEP-based BCIs, are analyzed for the first time.Ministerio de Ciencia e Innovación/AEI- FEDER [TED2021-129915B-I00, RTC2019-007350-1 y PID2020-115468RB-I00

Design and Performance of Rate-compatible Non-Binary LDPC Convolutional Codes

In this paper, we present a construction method of non-binary low-density parity-check (LDPC) convolutional codes. Our construction method is an extension of Felstroem and Zigangirov construction for non-binary LDPC convolutional codes. The rate-compatibility of the non-binary convolutional code is also discussed. The proposed rate-compatible code is designed from one single mother (2,4)-regular non-binary LDPC convolutional code of rate 1/2. Higher-rate codes are produced by puncturing the mother code and lower-rate codes are produced by multiplicatively repeating the mother code. Simulation results show that non-binary LDPC convolutional codes of rate 1/2 outperform state-of-the-art binary LDPC convolutional codes with comparable constraint bit length. Also the derived low-rate and high-rate non-binary LDPC convolutional codes exhibit good decoding performance without loss of large gap to the Shannon limits.Comment: 8 pages, submitted to IEICE transactio

Non-binary Living in a Binary World: The Unlabeled Experience

Both popular media and social science research suggest that gender/sexual identities and roles that have dominated western society are being challenged (Budgeon, 2014). Heteronormative assumptions and the gender binary are rapidly evolving to capture experiences that reflect greater diversity (Diamond, 2005; Nagoshi et al., 2012), including those that extend beyond labels. We surveyed 915 individuals regarding their gender identity, sexual orientation, and numerous psychological measures related to well-being, in order to understand the experience of those who choose to remain unlabeled. The data would suggest that those not ascribing to the gender binary have lower reported satisfaction with life across several axes when compared to cisgender participants. Explaining their ‘unlabeled’ status, participants described their primary identification as human, expressed discomfort with gender-based assumptions and rejected constrictions of the gender binary

Homomorphisms of binary Cayley graphs

A binary Cayley graph is a Cayley graph based on a binary group. In 1982, Payan proved that any non-bipartite binary Cayley graph must contain a generalized Mycielski graph of an odd-cycle, implying that such a graph cannot have chromatic number 3. We strengthen this result first by proving that any non-bipartite binary Cayley graph must contain a projective cube as a subgraph. We further conjecture that any homo- morphism of a non-bipartite binary Cayley graph to a projective cube must be surjective and we prove some special case of this conjecture

Multiplicatively Repeated Non-Binary LDPC Codes

We propose non-binary LDPC codes concatenated with multiplicative repetition codes. By multiplicatively repeating the (2,3)-regular non-binary LDPC mother code of rate 1/3, we construct rate-compatible codes of lower rates 1/6, 1/9, 1/12,... Surprisingly, such simple low-rate non-binary LDPC codes outperform the best low-rate binary LDPC codes so far. Moreover, we propose the decoding algorithm for the proposed codes, which can be decoded with almost the same computational complexity as that of the mother code.Comment: To appear in IEEE Transactions on Information Theor