Papers by Nicoladie D Tam
Academia Engineering, Jun 25, 2025
A hands-free, wearable brain–computer interface (BCI) with fault tolerance is proposed for indivi... more A hands-free, wearable brain–computer interface (BCI) with fault tolerance is proposed for individuals with quadriplegia, enabling safe wheelchair control. It anticipates operational failures with fault-recovery methods to mitigate catastrophic outcomes. A multimodal system validates decoded signals for sensor consistency and confirms user intentions. The primary imaging system utilizes optical sensors to monitor brain signals, while a supplementary system employs accelerometers and gyroscopes to detect head movements. A third subsystem recognizes voice commands via built-in microphones. The primary control decodes the direction of movement, and the secondary confirms this through head tilting. A third redundancy uses voice commands to confirm or override wheelchair operations. Although cumbersome, head movements and voice commands are essential for users who are paralyzed and unable to press buttons in emergencies. Head motion sensors also detect headset slippage, halting operations immediately in the event of a headset drop. An adaptive voting system employing a majority-rule method filters out inconsistent outliers by utilizing historical patterns of consistency in the weight-sum voting process. To validate the interpretation of optical data collected from brain signals in the prefrontal cortex (PFC) using functional near-infrared spectroscopy (fNIRS), motor task experiments were conducted with human subjects performing horizontal hand movements in four orthogonal directions. The results indicated that oxy-hemoglobin (oxy-Hb) and deoxy-hemoglobin (deoxy-Hb) signals exhibited directional specificity, with responses reversing during opposing movements. It suggests that neural activity reflects the direction of movement. The consistency of the decoded results is verified by hemodynamic variables, with oxy-Hb and deoxy-Hb signals covarying inversely. Phase relationships between hemodynamic variables also changed depending on the direction of movement. An analysis revealed that the dynamics of vasodilation and vasoconstriction varied, indicating conditions where the oxygen supply could not meet metabolic demand in specific movement directions. The design allows users to choose a lightweight headband for cost-effective PFC monitoring or a helmet for whole-brain signal detection. The wearable design also provides wireless or wired headset options for communication with the controller located on the wheelchair. Future developments will address headset slippage challenges through adaptive signal processing, ensuring the commercial viability and reliability of the product.
tional Model of The Theoretical Interpretation Of Neuro
Theoretical derivation of EMOTION-I model for emotional feel of sensation
Advances in Image and Video Processing, Feb 1, 2014
Motion-detection, edge-detection, and orientation-detection often require spatial
computation of... more Motion-detection, edge-detection, and orientation-detection often require spatial
computation of the light intensity difference between neighboring pixel cells. Pre-processing
the image at the retinal level can improve the computational efficiency when the parallel
processing can be achieved naturally by the spatial arrangement of the pixel-array. Pixel-arrays
that require spatial pre-processing computation have different geometric constraints than plain
pixel-arrays that do not require such local computation. Our analysis shows that geometric
optimization of pixel-arrays can be achieved by using hexagonal arrays over rectilinear arrays.
Hexagonal arrays improve the packing density, and reduce the complexity of the spatial
computation compared to rectilinear square and octagonal arrays. They also provide geometric
symmetry for efficient computation not only at the contiguous neighboring cell level, but also
at the higher-order neighboring cell level. The light intensity difference at the higher-order cell
level is used to compute the first-order and second-order time-derivatives for velocity and
acceleration detections of the visual scene, respectively. Thus, hexagonal arrays increase the
computational efficiency by using a symmetric configuration that allows pre-processing of
spatial information of the visual scene using hardware implementations that are repeatable in
all higher-order neighboring pixels.
A Joint Cross Interval Difference Analysis for Detecting Coupling Trends between Neurons
Springer eBooks, 1997
We present a new spike train analysis technique based on interval difference statistics. The Join... more We present a new spike train analysis technique based on interval difference statistics. The Joint Cross Interval Difference (JCID) scatter plot is introduced to examine the dependency relationship between adjacent CIDs in a spike train allowing for inferences to be made about local cross train trends. Monotonically increasing, decreasing, constant, or alternatively varying CIDs will appear in separate quadrants in this JCID scatter plot. The method was applied to simulated spike trains in order to display the capabilities of this new technique. Repeated cross train trends between pairs of neurons can seen as clusters and bands of points in specific quadrants of this new scatter plot.
This paper is a brief review on the book 'Capital in the Twenty-First Century' by the French scho... more This paper is a brief review on the book 'Capital in the Twenty-First Century' by the French scholar Thomas Piketty. The book has started a new debate about inequality and capital taxation in Europe. It provides interesting empirical facts and develops a theory of the functioning of capitalist economies. However, I personally think the book is less convincing than recognized in the public debate. The demonstrated theory of economic growth in the book is elusive and lacks a psychological and behavioral underpinning. In fact, I do think that the increasing inequality and economic divergence are caused by capitalism but the psychological and behavioral aspects of humans are of similar or greater significance. Therefore, Piketty's argument does not stimulate an open and scientifically founded debate in all aspects.
We introduced a multiple single-unit spike train analysis technique to deduce the burst "rin... more We introduced a multiple single-unit spike train analysis technique to deduce the burst "ring patterns in one neuron that are temporally correlated to the spike generation in another neuron. This analysis considers the contribution of temporal summation of burst "rings in one neuron that is correlated to the probability of spike "ring in another neuron. The result shows that the analysis can extract the number of spikes and the duration of burst pattern. 2001
Abstract: A theoretical analysis of the cumulative sum (CUSUM) technique for detecting a series o... more Abstract: A theoretical analysis of the cumulative sum (CUSUM) technique for detecting a series of time signals from noisy background is provided. The statistic using CUSUM-slope is introduced as a measure for capturing the average of signals within the time-window, in which the slope is computed. This provides a time-independent method for estimating the signal content within the time-window. The detection criterion is provided for different window-lengths. The results showed that this CUSUM-slope statistic is highly sensitive to the detection of subtle hidden trends in the data sequence with noise filtered even in very low signal-to-noise environment.
Open Access
Having developed a computational model for emotional response (Emotional-Gain Model) [1-4] and a ... more Having developed a computational model for emotional response (Emotional-Gain Model) [1-4] and a model for fairness (Fairness-Equity Model) [5] that quantified emotional bias and fairness bias, we will address the gender difference between the perception of love. We employed the experimental paradigm called “ultimatum game ” to elicit emotional responses to the sharing of love and money. The experimental paradigm essentially asks human subjects to split a sum of money or love such that their emotional response to fairness can be assessed. The results showed that although male and female respond very similarly in their emotional perception and fairness perception, except for the subtle difference as revealed by our Emotional-Gain and Fairness-Equity Models. The results revealed that female tends to recognize the full spectrum of emotions (both positive and negative) while male tends to recognize the positive emotions more often than the negative emotions. Furthermore, female tends to...
The equivalence of an infinite series, such as (0.999... = 1) to a finite number is often not int... more The equivalence of an infinite series, such as (0.999... = 1) to a finite number is often not intuitively obvious to understand for most students. Yet, it is helpful to use an intuitive method to derive the equivalence that is familiar to most elementary school students. In this paper, a simple proof of the equality of 0.999... and 1 is provided by a non-traditional method using long division with an alternate quotient. This alternate method that uses long division to prove an infinite series of numbers can stimulate the imagination of students to use abstraction to understand the mathematical concept of infinity. This can be done without the use of geometric series.
Quantification of Happy Emotion: Dependence on Decisions
Psychology and Behavioral Sciences, 2014
Quantification of Happy Emotion: Proportionality Relationship to Gain/Loss
Psychology and Behavioral Sciences, 2014
Quantification of emotional bias by an Emotional-Gain Model
BMC Neuroscience, 2011
BMC Neuroscience, 2011
Having developed a computational model for emotional response (Emotional-Gain Model) [1-4] and a ... more Having developed a computational model for emotional response (Emotional-Gain Model) [1-4] and a model for fairness (Fairness-Equity Model) [5] that quantified emotional bias and fairness bias, we will address the gender difference between the perception of love. We employed the experimental paradigm called "ultimatum game" to elicit emotional responses to the sharing of love and money. The experimental paradigm essentially asks human subjects to split a sum of money or love such that their emotional response to fairness can be assessed. The results showed that although male and female respond very similarly in their emotional perception and fairness perception, except for the subtle difference as revealed by our Emotional-Gain and Fairness-Equity Models. The results revealed that female tends to recognize the full spectrum of emotions (both positive and negative) while male tends to recognize the positive emotions more often than the negative emotions. Furthermore, female tends to value love much more important than money, whereas male tends to value money more than love at a subconscious level. Both genders are consciously aware of the objectivity but responded subjectively to what they considered as important, with the value system emphasizing more on money for male whereas the value system emphasizes more on love for female. This confirms the emotional bias and fairness bias quantitative by the emotional and fairness models experimentally.
Contributing factors in judgment of fairness by monetary value
BMC Neuroscience, 2011
Quantification of fairness bias by a Fairness-Equity Model
BMC Neuroscience, 2011
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Papers by Nicoladie D Tam
computation of the light intensity difference between neighboring pixel cells. Pre-processing
the image at the retinal level can improve the computational efficiency when the parallel
processing can be achieved naturally by the spatial arrangement of the pixel-array. Pixel-arrays
that require spatial pre-processing computation have different geometric constraints than plain
pixel-arrays that do not require such local computation. Our analysis shows that geometric
optimization of pixel-arrays can be achieved by using hexagonal arrays over rectilinear arrays.
Hexagonal arrays improve the packing density, and reduce the complexity of the spatial
computation compared to rectilinear square and octagonal arrays. They also provide geometric
symmetry for efficient computation not only at the contiguous neighboring cell level, but also
at the higher-order neighboring cell level. The light intensity difference at the higher-order cell
level is used to compute the first-order and second-order time-derivatives for velocity and
acceleration detections of the visual scene, respectively. Thus, hexagonal arrays increase the
computational efficiency by using a symmetric configuration that allows pre-processing of
spatial information of the visual scene using hardware implementations that are repeatable in
all higher-order neighboring pixels.