Identifying Neural Correlates of Insightful Problem Solving with EEG Evidence
Insight means solving a trivial unknown problem through a sudden spark which gives an experience ... more Insight means solving a trivial unknown problem through a sudden spark which gives an experience of enthusiasm or ‘Aha!’ feeling. This study involves identification of neural correlates during performance of cognitive task, during an insightful experiment such as remote associates test and rebus puzzle on E-Prime 3.0. The data is recorded using 32 channels EEG and Brain Vision recorder, and the analysis is done using Brainstorm software. The experiment is performed on 25 healthy right-handed subjects of age group 19–22 years. Temporal analysis of recorded EEG data indicates there is a positive correlation of activation in right parietal occipital region corresponding to ‘Aha’ and non-Aha! feelings; there is a negative correlation of activation of temporal region in the right hemisphere, clearly indicating that T8 and FC6 is activated when the problem is solved through insight. Spectral analysis of EEG indicates that there is a sudden increase in gamma activity/gamma burst in right s...
Identifying Neural Correlates in Stroop Task
Decades of research has been dedicated to prove the effect of meditation on human brain. This stu... more Decades of research has been dedicated to prove the effect of meditation on human brain. This study is based on examining the effect of transcendental meditation (a style of meditation practice) on cognitive ability by identifying neural correlates in Stroop task [23]. Task was performed on 43 healthy right-handed subjects categorized as 13 control subjects (no formal training of meditation), 11 aspirants (aspirants of transcendental meditation), 7 transcendental meditators (TMs), 12 ultra-transcendental meditators (UTMs) [22] using MEG. Participants were instructed to relax or to meditate according to their choice for 10 min before starting Stroop task. Temporal analysis shows that meditators are slow but more accurate responder than the control subject. Difference in response time of incongruent trial compared to congruent trial for meditators is less as compared to control subject. Analysis of the data obtained through spatial localization shows activation in some specific parts ...
As species evolved, consciousness (awareness) manifested at different levels: physical, mental, a... more As species evolved, consciousness (awareness) manifested at different levels: physical, mental, and subtle. But why different species exhibit different grades of consciousness continues to intrigue researchers. A plausible reason could be that adaptation to environmental changes, and hence survival and evolution, all depend on the level of consciousness species possess. This could be the reason why evolutionarily older species (with lower order consciousness) only implicitly (slowly and unconsciously) adapt, whereas evolved species (with higher order consciousness) explicitly (quickly and consciously) adapt to unforeseen situations gaining tremendous survival advantage. This ability requires exploring innumerable possibilities including representations that may not have been experienced before and requires faster, brain-wide computations. We argue that the transition from slow adaptation to fast learning can be explained by considering two different regimes of computation in the bra...
Sequential development of orientation nd ocular dominance maps: a reaction-diffusion approach
Comparison between two Biologically Inspired Algorithms: 'Cepstral and Phase Method' for Stereoscopic Depth Estimation
Performance Evaluation of a Millimeter Wave MIMO Hybrid Beamforming System
Massive MIMO (multiple-input-multiple-output) technology along with beamforming has become the ma... more Massive MIMO (multiple-input-multiple-output) technology along with beamforming has become the mainstream feature in 5G physical layer technologies to provide high increase in spectral efficiency and to combat the high propagation loss at high frequencies. Unlike conventional MIMO systems where all the signal processing is carried out in the digital domain, Hybrid Analog-Digital (HAD) signal processing or hybrid beamforming has the potential to reduce cost and power consumption. In this paper, a novel hybrid beamforming architecture based on the orthogonal matching pursuit (OMP) algorithm is exploited for a single-user system in which massive antenna array is operated by a limited number of transmit and receive RF chains. A simulation model is studied for performance of the hybrid beamformer compared to conventional digital beamformer of the proposed system. Results show spectral efficiency as performance metric which shows near optimal efficiency using hybrid beamforming weights co...
Science Journal of Circuits, Systems and Signal Processing, 2012
The paper propose a modified high frequency current controlled current conveyor CMOS circuit CCCI... more The paper propose a modified high frequency current controlled current conveyor CMOS circuit CCCII where current gain, current controlling intrinsic impedance and circuit offsets are programmable independently to desired values within a specific field range after fabrication with the help of field programmable floating gate transistors FGMOS. The programmable charge at floating-gate of FGMOS using external voltages results in its threshold voltage variation, which in turn program the design (CCCII) specifications. The circuit occupies low power, about 1.509mW total power dissipation and shows higher temperature stability (0.0287uA/°C variation in output current with temperature change). With specific sizing and biasing condition, the current gain can be programmed from 0.2 to 2.1, intrinsic impedance from 15K to 51K, while offset current can be compensated, independently using each FGMOSFETs, respectively, with 13-bit precision. However the final programmable CCCII circuit with FGMOSFETs occupies 65µm × 54µm chip area. The circuit finds application in systems where field-programmability of the design using smaller sized hardware is required like universal filter, current control high frequency oscillator, etc as compared to the circuits using current control conveyor based FPAAs.
Stereopsis or depth perception is a critical aspect of information processing in the brain and is... more Stereopsis or depth perception is a critical aspect of information processing in the brain and is computed from the positional shift or disparity between the images seen by the two eyes. Various algorithms and their hardware implementation that compute disparity in real time have been proposed; however, most of them compute disparity through complex mathematical calculations that are difficult to realize in hardware and are biologically unrealistic. The brain presumably uses simpler methods to extract depth information from the environment and hence newer methodologies that could perform stereopsis with brain like elegance need to be explored. This paper proposes an innovative aVLSI design that leverages the columnar organization of ocular dominance in the brain and uses time-staggered Winner Take All (ts-WTA) to adaptively create disparity tuned cells. Physiological findings support the presence of disparity cells in the visual cortex and show that these cells surface as a result o...
Bio-inspired Algorithms to Reconstruct Stereoscopic Disparity
Communications in Computer and Information Science, 2011
Binocular disparity refers to the difference in image location of an object seen by the left and ... more Binocular disparity refers to the difference in image location of an object seen by the left and right eyes, resulting from the eyes’ horizontal separation. Bio-inspired systems aim to extract some interesting features from living beings, such as adaptability and fault tolerance, for including them in human-designed devices. The biological vision systems routinely accomplish complex visual tasks such as object recognition, stereoscopic vision and many more, which continue to challenge artificial systems. If any cell in the brain is dead, other cell takes over the dead cell and brain works in the normal way. Any bio-inspired system must be any day superior to any artificial method. In this paper, this paper presents some algorithms which are motivated from biological functioning, such as Cepstral filtering technique, phase method, reaction-diffusion algorithm. Further, this pa per compares cepstral filtering technique with phase method. These two algorithms are claimed as two different approaches, but in this paper we show that in essence they are same. Both the algorithms exploit only part of the functions used in the bio logical flow of data to reconstruct the depth perception. The algorithms look different as both follow different procedures and functions. If the computational steps are decomposed and compared then they are doing the same thing. Each step in both algorithms is same and only the functions used are different as they are just the mathematical way of representation. By comparing both the algorithms, the advantage of one can be benefited by the other. The equivalence condition has also been derived.
This paper demonstrates an analog field programmable RC Oscillator using a Floating-Gate Transist... more This paper demonstrates an analog field programmable RC Oscillator using a Floating-Gate Transistor. The programmable oscillator can attain a continuous range of time-periods lying in the programming precision range of Floating Gates. Floating-gate transistors add a programmability feature to the analog circuit making it a wide frequency range square wave generator. The circuit consists of two sub circuits: Current Generator circuit and Wave Generator circuit. The current of current generator circuit is programmable and mirrored to the wave generator to generate the desired square wave. A simulation model of the circuit built in T-Spice, 0.35μm CMOS process. The circuit results in a clock with continuously changing frequency. The circuit can also be operated at a very low supply voltage (1.8V). Theoretically estimated, effective chip area of the circuit is less. The variations with change in temperature can be compensated.
International Journal of VLSI Design & Communication Systems, 2010
This paper presents a circuit of a high-precision, wide ranged, analog clock generator with on-ch... more This paper presents a circuit of a high-precision, wide ranged, analog clock generator with on-chip programmability feature using Floating-gate transistors. The programmable oscillator can attain a continuous range of time-periods lying in the programming precision range of Floating Gates. The circuit consists of two sub circuits: Current Generator circuit and Wave Generator circuit. The current of current generator circuit is programmable and mirrored to the wave generator to generate the desired square wave. The topology is well suited to applications like clocking high performance ADCs and DACs as well as used as the internal clock in structured analog CMOS designs. A simulation model of the circuit was built in T-Spice, 0.35µm CMOS process. The circuit results in finely tuned clock with programmability precision of about 13bit [1]. Simulation results show high amount of temperature insensitivity (0.507ns/°C) for a large range of thermal conditions. The proposed circuit can compensate any change in temperature. The circuit design can be operated at low supply voltage i.e., 1v.
Adaptive Analog Disparity Model using Ocular Dominance Map
Proceedings of the 2nd International Conference on Perception and Machine Intelligence - PerMIn '15, 2015
Biological vision system extracts depth from the difference in the left and right eye images. Num... more Biological vision system extracts depth from the difference in the left and right eye images. Numerous algorithms and their hardware implementations that compute disparity in real time have been proposed. However, most of them compute disparity through complicated functions that are difficult to realize in hardware and are biologically unrealistic. The brain most likely uses simpler methods to extract depth information and hence newer methodologies that could perform stereopsis with brain like elegance need to be explored. Physiological findings support the presence of disparity tuned cells in the visual cortex and show that the perception of depth evolves with experience and is not present at the time of birth. Therefore adaptively learning disparities may indeed be the algorithm underlying depth computations in the developing brain. This paper proposes a novel VLSI design using time-staggered Winner Take All to adaptively create disparity tuned cells.
The brain self-organizes into feature maps or neural assemblies on receiving inputs. Similar self... more The brain self-organizes into feature maps or neural assemblies on receiving inputs. Similar self-organization is possible in artificial systems only if the principles that the brain employs are exploited. Existing models explaining feature map formation cover only some aspects of local feature map formation. It is unlikely that the brain employs different mechanisms to form local and global feature maps and hence there is a need to explore a single mechanism that could account for neural interactions at all levels. If we take the brain to coexist as a quantum and a classical system, certain insights can be obtained about neural development. In this paper we explore a quantum hebbian model of interaction between the quantum and classical processes in the brain, which in synergy with mental force of directed attention, seems to have the potential to explain the formation of both local and global feature maps. Introducing this duality also helps us address higher level issues like mind wandering, zombie modes, volition etc.
2011 IEEE Computer Society Annual Symposium on VLSI, 2011
This work presents fine tunability in simple single ended active inductor using non-volatile, on-... more This work presents fine tunability in simple single ended active inductor using non-volatile, on-chip, post fabrication and indirect programming in floating gate transistor, employed as tunable feedback resistor in the design. The inductor find applications in navigation(L band:1to2GHz) and in mobile telecommunication base-stations(1.8-2.1GHz) as it generate several inductances in nH (3-7nH) at few GHz frequencies (1-2.5GHz) with highly precise programming resolution (about 13bit i.e., 2 13 inductance values) in which, fine tunability is in priority to operating speed. It shows temperature and noise sensitivity better than the design using feedback resistor.
Threshold Trimming Based Design of a CMOS Programmable Operational Amplifier
VLSI Design, 2006
We propose a threshold trimming based design of a CMOS operational amplifier (op-amp) whose speci... more We propose a threshold trimming based design of a CMOS operational amplifier (op-amp) whose specifications are varied over a wide range through a continuous and independent programming procedure. The programmable parameters include gain, gain-bandwidth, slew rate, input/output range and offset voltage. Observable behavior of op-amp is linked to threshold voltage (VT) of constituent mosfets as explicit equations. An algorithm is
Design of a bio-inspired CMOS circuit realizing features of binocular rivalry between left and right eye
2013 International Mutli-Conference on Automation, Computing, Communication, Control and Compressed Sensing (iMac4s), 2013
International Journal of Online Engineering (iJOE), 2013
Currently most universities have Online-learning environments ready to be remotely accessed throu... more Currently most universities have Online-learning environments ready to be remotely accessed through the internet. Remote labs have emerged as a viable alternative for developing skills and to learn how to deal with laboratory instruments in the absence of real labs. Remote labs can provide remote access to hardware and simulators, and can allow students to perform experiments without time and location restrictions. In addition, they provide the necessary guidance and also constrain user operation in order to avoid dangerous situations (both from set-up integrity and from the userâ??s point of view). In this paper, we describe a hierarchical model of a remote lab for analog communication that is focused for undergraduate and engineering students. The lab brings together a two level learning approach. i). A basic device level approach for new users and ii). An advanced block level approach for advanced users. Features like on-demand service, virtual breadboard, interactive instrument ...
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