Abstract: The advancements in the field of Artificial Intelligence (AI) and technology has led to an evolution of an intelligent era. Neural networks, having the computational power and learning ability similar to the brain is one of the key AI technologies. Neuromorphic computing system (NCS) consists of the synaptic device, neuronal circuit, and neuromorphic architecture. Memristor are a promising candidate for neuromorphic computing systems, but when it comes to neuromorphic computing, the conductance behavior of the synaptic memristor or neuronal memristor needs to be studied thoroughly in order to fathom the neuroscience or computer science. Furthermore, there is a need of more simulation work for utilizing the existing device properties and providing guidance to the development of future devices for different performance requirements. Hence, development of NCS needs more simulation work to make use of existing device properties. This work aims to provide an insight to build neuronal circuits using memristors to achieve a Memristor based NCS. Here we throw a light on the research conducted in the field of memristors for building analog and digital circuits in order to motivate the research in the field of NCS by building memristor based neural circuits for advanced AI applications. This literature is a step in the direction where we describe the various Key findings about memristors and its analog and digital circuits implemented over the years which can be further utilized in implementing the neuronal circuits in the NCS. This work aims to help the electronic circuit designers to understand how the research progressed in memristors and how these findings can be used in implementing the neuronal circuits meant for the recent progress in the NCS.
Abstract: The late detection and subjectivity of the assessment of Autism Spectrum Disorder (ASD) imposed a difficulty for the children’s clinical and familiar environment. The results showed in this paper, are part of a research project about the assessment and training of social skills in children with ASD, whose overall goal is the use of virtual environments together with physiological measures in order to find a new model of objective ASD assessment based on implicit brain processes measures. In particular, this work tries to contribute by studying the differences and changes in the Skin Conductance Response (SCR) and Eye Tracking (ET) between a typical development group (TD group) and an ASD group (ASD group) after several combined stimuli using a low cost Immersive Virtual Environment (IVE). Subjects were exposed to a virtual environment that showed natural scenes that stimulated visual, auditory and olfactory perceptual system. By exposing them to the IVE, subjects showed natural behaviors while measuring SCR and ET. This study compared measures of subjects diagnosed with ASD (N = 18) with a control group of subjects with typical development (N=10) when exposed to three different conditions: only visual (V), visual and auditory (VA) and visual, auditory and olfactory (VAO) stimulation. Correlations between SCR and ET measures were also correlated with the Autism Diagnostic Observation Schedule (ADOS) test. SCR measures showed significant differences among the experimental condition between groups. The ASD group presented higher level of SCR while we did not find significant differences between groups regarding DF. We found high significant correlations among all the experimental conditions in SCR measures and the subscale of ADOS test of imagination and symbolic thinking. Regarding the correlation between ET measures and ADOS test, the results showed significant relationship between VA condition and communication scores.
Abstract: Electrical resistivity investigation was conducted in vicinity of Tarbela Ghazi, in order to study the subsurface layer with a view of determining the depth to the aquifer and thickness of groundwater potential zones. Vertical Electrical Sounding (VES) using Schlumberger array was carried out at 16 VES stations. Well logging data at four tube wells have been used to mark the super saturated zones with great discharge rate. The present paper shows a geoelectrical identification of the lithology and an estimate of the relationship between the resistivity and Dar Zarrouk parameters (transverse unit resistance and longitudinal unit conductance). The VES results revealed both homogeneous and heterogeneous nature of the subsurface strata. Aquifer is unconfined to confine in nature, and at few locations though perched aquifer has been identified, groundwater potential zones are developed in unconsolidated deposits layers and more than seven geo-electric layers are observed at some VES locations. Saturated zones thickness ranges from 5 m to 150 m, whereas at few area aquifer is beyond 150 m thick. The average anisotropy, transvers resistance and longitudinal conductance values are 0.86 %, 35750.9821 Ω.m2, 0.729 Siemens, respectively. The transverse unit resistance values fluctuate all over the aquifer system, whereas below at particular depth high values are observed, that significantly associated with the high transmissivity zones. The groundwater quality in all analyzed samples is below permissible limit according to World Health Standard (WHO).
Abstract: Infrared thermography is a non-destructive test method used to estimate surface temperatures based on the amount of electromagnetic energy radiated by building envelope components. These surface temperatures are indicators of various qualitative building envelope deficiencies such as locations and extent of heat loss, thermal bridging, damaged or missing thermal insulation, air leakage, and moisture presence in roof, floor, and wall assemblies. Although infrared thermography is commonly used for qualitative deficiency detection in buildings, this study assesses its use as a quantitative method to estimate the overall thermal conductance value (U-value) of the exterior above-grade walls of a study home. The overall U-value of exterior above-grade walls in a home provides useful insight into the energy consumption and thermal comfort of a home. Three methodologies from the literature were employed to estimate the overall U-value by equating conductive heat loss through the exterior above-grade walls to the sum of convective and radiant heat losses of the walls. Outdoor infrared thermography field measurements of the exterior above-grade wall surface and reflective temperatures and emissivity values for various components of the exterior above-grade wall assemblies were carried out during winter months at the study home using a basic thermal imager device. The overall U-values estimated from each methodology from the literature using the recorded field measurements were compared to the nominal exterior above-grade wall overall U-value calculated from materials and dimensions detailed in architectural drawings of the study home. The nominal overall U-value was validated through calendarization and weather normalization of utility bills for the study home as well as various estimated heat loss quantities from a HOT2000 computer model of the study home and other methods. Under ideal environmental conditions, the estimated overall U-values deviated from the nominal overall U-value between ±2% to ±33%. This study suggests infrared thermography can estimate the overall U-value of exterior above-grade walls in low-rise residential homes with a fair amount of accuracy.
Abstract: Spin-orbit gap feature in energy dispersion of
one-dimensional devices is revealed via strong spin-orbit interaction
(SOI) effects under Zeeman field. We describe the utilization
of a finger-gate or a top-gate to control the spin-dependent
transport characteristics in the SOI-Zeeman influenced split-gate
devices by means of a generalized spin-mixed propagation matrix
method. For the finger-gate system, we find a bound state in
continuum for incident electrons within the ultra-low energy regime.
For the top-gate system, we observe more bound-state features
in conductance associated with the formation of spin-associated
hole-like or electron-like quasi-bound states around band thresholds,
as well as hole bound states around the reverse point of the
energy dispersion. We demonstrate that the spin-dependent transport
behavior of a top-gate system is similar to that of a finger-gate system
only if the top-gate length is less than the effective Fermi wavelength.
Abstract: In the current study, energy and exergy analysis of a 65 MW steam power plant was carried out. This study investigated the effect of variations of overall conductance of the super heater on the performance of an existing steam power plant located in Derna, Libya. The performance of the power plant was estimated by a mathematical modelling which considers the off-design operating conditions of each component. A fully interactive computer program based on the mass, energy and exergy balance equations has been developed. The maximum exergy destruction has been found in the steam generation unit. A 50% reduction in the design value of overall conductance of the super heater has been achieved, which accordingly decreases the amount of the net electrical power that would be generated by at least 13 MW, as well as the overall plant exergy efficiency by at least 6.4%, and at the same time that would cause an increase of the total exergy destruction by at least 14 MW. The achieved results showed that the super heater design and operating conditions play an important role on the thermodynamics performance and the fuel utilization of the power plant. Moreover, these considerations are very useful in the process of the decision that should be taken at the occasions of deciding whether to replace or renovate the super heater of the power plant.
Abstract: Freezing and thawing are considered to be one of the major causes of concrete deterioration in the cold regions. This study aimed at assessing the freezing and thawing of concrete within the cover zone by monitoring the formation of ice and melting at different temperatures using electrical measurement technique. A multi-electrode array system was used to obtain the resistivity of ice formation and melting at discrete depths within the cover zone of the concrete. A total number of four concrete specimens (250 mm x 250 mm x 150 mm) made of ordinary Portland cement concrete and ordinary Portland cement replaced by 65% ground granulated blast furnace slag (GGBS) is investigated. Water/binder ratios of 0.35 and 0.65 were produced and ponded with water to ensure full saturation and then subjected to freezing and thawing process in a refrigerator within a temperature range of -30 0C and 20 0C over a period of time 24 hours. The data were collected and analysed. The obtained results show that the addition of GGBS changed the pore structure of the concrete which resulted in the decrease in conductance. It was recommended among others that, the surface of the concrete structure should be protected as this will help to prevent the instantaneous propagation of ice trough the rebar and to avoid corrosion and subsequent damage.
Abstract: Maximum Power Point Tracking (MPPT) has played a vital role to enhance the efficiency of solar photovoltaic (PV) power generation under varying atmospheric temperature and solar irradiation. However, it is hard to track the maximum power point using conventional linear controllers due to the natural inheritance of nonlinear I-V and P-V characteristics of solar PV systems. Fuzzy Logic Controller (FLC) is suitable for nonlinear system control applications and eliminating oscillations, circuit complexities present in the conventional perturb and observation and incremental conductance methods respectively. Hence, in this paper, FLC is proposed for tracking exact MPPT of solar PV power generation system under varying solar irradiation conditions. The effectiveness of the proposed FLC-based MPPT controller is validated through simulation and analysis using MATLAB/Simulink.
Abstract: This paper presents a 5-V to 30-V current-mode boost converter for powering the drive circuit of a micro-electro-mechanical sensor. The design of a transconductance amplifier and an integrated current sensing circuit are presented. In addition, essential building blocks for power-on protection such as a soft-start and clamp block and supply and clock ready block are discussed in details. The chip is fabricated in a 0.18-μm CMOS process. Measurement results show that the soft-start and clamp block can effectively limit the inrush current during startup and protect the boost converter from startup failure.
Abstract: The purpose of this paper is to study and compare two maximum power point tracking (MPPT) algorithms in a photovoltaic simulation system and also show a simulation study of maximum power point tracking (MPPT) for photovoltaic systems using perturb and observe algorithm and Incremental conductance algorithm. Maximum power point tracking (MPPT) plays an important role in photovoltaic systems because it maximize the power output from a PV system for a given set of conditions, and therefore maximize the array efficiency and minimize the overall system cost. Since the maximum power point (MPP) varies, based on the irradiation and cell temperature, appropriate algorithms must be utilized to track the (MPP) and maintain the operation of the system in it. MATLAB/Simulink is used to establish a model of photovoltaic system with (MPPT) function. This system is developed by combining the models established of solar PV module and DC-DC Boost converter. The system is simulated under different climate conditions. Simulation results show that the photovoltaic simulation system can track the maximum power point accurately.
Abstract: In this work we make a bifurcation analysis for a
single compartment representation of Traub model, one of the most
important conductance-based models. The analysis focus in two
principal parameters: current and leakage conductance. Study of
stable and unstable solutions are explored; also Hop-bifurcation and
frequency interpretation when current varies is examined. This study
allows having control of neuron dynamics and neuron response when
these parameters change. Analysis like this is particularly important
for several applications such as: tuning parameters in learning
process, neuron excitability tests, measure bursting properties of the
neuron, etc. Finally, a hardware implementation results were
developed to corroborate these results.
Abstract: In recent years, the use of renewable energy resources
instead of pollutant fossil fuels and other forms has increased.
Photovoltaic generation is becoming increasingly important as a
renewable resource since it does not cause in fuel costs, pollution,
maintenance, and emitting noise compared with other alternatives
used in power applications. In this paper, Perturb and Observe and
Incremental Conductance methods are used to improve energy
conversion efficiency under different environmental conditions. PI
controllers are used to control easily DC-link voltage, active and
reactive currents. The whole system is simulated under standard
climatic conditions (1000 W/m2, 250C) in MATLAB and the
irradiance is varied from 1000 W/m2 to 300 W/m2. The use of PI
controller makes it easy to directly control the power of the grid
connected PV system. Finally the validity of the system will be
verified through the simulations in MATLAB/Simulink environment.
Abstract: An experiment to verify the relationships between
physiological indexes of an e-learner and the presence or absence of an
operation during e-learning is described. Electroencephalogram
(EEG), hemoencephalography (HEG), skin conductance (SC), and
blood volume pulse (BVP) values were measured while participants
performed experimental learning tasks. The results show that there are
significant differences between the SC values when reading with
clicking on learning materials and the SC values when reading without
clicking, and between the HEG ratio when reading (with and without
clicking) and the HEG ratio when resting for four of five participants.
We conclude that the SC signals can be used to estimate whether or not
a learner is performing an active task and that the HEG ratios can be
used to estimate whether a learner is learning.
Abstract: A geoelectric survey was carried out in some parts of
Angwan Gwari, an outskirt of Lapai Local Government Area on
Niger State which belongs to the Nigerian Basement Complex, with
the aim of evaluating the soil corrosivity, aquifer transmissivity and
protective capacity of the area from which aquifer characterisation
was made. The G41 Resistivity Meter was employed to obtain fifteen
Schlumberger Vertical Electrical Sounding data along profiles in a
square grid network. The data were processed using interpex 1-D
sounding inversion software, which gives vertical electrical sounding
curves with layered model comprising of the apparent resistivities,
overburden thicknesses, and depth. This information was used to
evaluate longitudinal conductance and transmissivities of the layers.
The results show generally low resistivities across the survey area
and an average longitudinal conductance variation from
0.0237Siemens in VES 6 to 0.1261Siemens in VES 15 with almost
the entire area giving values less than 1.0 Siemens. The average
transmissivity values range from 96.45 Ω.m2 in VES 4 to 299070
Ω.m2 in VES 1. All but VES 4 and VES14 had an average
overburden greater than 400 Ω.m2, these results suggest that the
aquifers are highly permeable to fluid movement within, leading to
the possibility of enhanced migration and circulation of contaminants
in the groundwater system and that the area is generally corrosive.
Abstract: The use of solar energy as a source for pumping water
is one of the promising areas in the photovoltaic (PV) application.
The energy of photovoltaic pumping systems (PVPS) can be widely
improved by employing an MPPT algorithm. This will lead
consequently to maximize the electrical motor speed of the system.
This paper presents a modified incremental conductance (IncCond)
MPPT algorithm with direct control method applied to a standalone
PV pumping system. The influence of the algorithm parameters on
system behavior is investigated and compared with the traditional
(INC) method. The studied system consists of a PV panel, a DC-DC
boost converter, and a PMDC motor-pump. The simulation of the
system by MATLAB-SIMULINK is carried out. Simulation results
found are satisfactory.
Abstract: A novel design technique employing CMOS Current
Feedback Operational Amplifier (CFOA) is presented. The feature of
consumption very low power in designing pseudo-OTA is used to
decreasing the total power consumption of the proposed CFOA. This
design approach applies pseudo-OTA as input stage cascaded with
buffer stage. Moreover, the DC input offset voltage and harmonic
distortion (HD) of the proposed CFOA are very low values compared
with the conventional CMOS CFOA due to the symmetrical input
stage. P-Spice simulation results are obtained using 0.18μm MIETEC
CMOS process parameters and supply voltage of ±1.2V, 50μA
biasing current. The p-spice simulation shows excellent improvement
of the proposed CFOA over existing CMOS CFOA. Some of these
performance parameters, for example, are DC gain of 62. dB, openloop
gain bandwidth product of 108 MHz, slew rate (SR+) of
+71.2V/μS, THD of -63dB and DC consumption power (PC) of
2mW.
Abstract: In this paper, the transient device performance analysis
of n-type Gate Inside JunctionLess Transistor (GI-JLT) has been
evaluated. 3-D Bohm Quantum Potential (BQP) transport device
simulation has been used to evaluate the delay and power dissipation
performance. GI-JLT has a number of desirable device parameters
such as reduced propagation delay, dynamic power dissipation,
power and delay product, intrinsic gate delay and energy delay
product as compared to Gate-all-around transistors GAA-JLT. In
addition to this, various other device performance parameters namely,
on/off current ratio, short channel effects (SCE), transconductance
Generation Factor (TGF) and unity gain cut-off frequency (fT ) and
subthreshold slope (SS) of the GI-JLT and GAA-JLT have been
analyzed and compared. GI-JLT shows better device performance
characteristics than GAA-JLT for low power and high frequency
applications, because of its larger gate electrostatic control on the
device operation.
Abstract: The most important component affecting the
efficiency of photovoltaic power systems are solar panels. In other
words, efficiency of these systems are significantly affected due to
the being low efficiency of solar panel. Thus, solar panels should be
operated under maximum power point conditions through a power
converter. In this study, design of boost converter has been carried
out with maximum power point tracking (MPPT) algorithm which is
incremental conductance (Inc-Cond). By using this algorithm,
importance of power converter in MPPT hardware design, impacts of
MPPT operation have been shown. It is worth noting that initial
operation point is the main criteria for determining the MPPT
performance. In addition, it is shown that if value of load resistance is
lower than critical value, failure operation is realized. For these
analyzes, direct duty control is used for simplifying the control.
Abstract: Since the output characteristics of photovoltaic (PV) system depends on the ambient temperature, solar radiation and load impedance, its maximum power point (MPP) is not constant. Under each condition PV module has a point at which it can produce its MPP. Therefore, a maximum power point tracking (MPPT) method is needed to uphold the PV panel operating at its MPP. This paper presents comparative study between the conventional MPPT methods used in (PV) system: Perturb and Observe (P&O), Incremental Conductance (IncCond), andParticle Swarm Optimization (PSO) algorithmfor (MPPT) of (PV) system. To evaluate the study, the proposed PSO MPPT is implemented on a DC-DC cuk converter and has been compared with P&O and INcond methods in terms of their tracking speed, accuracy and performance by using the Matlab tool Simulink. The simulation result shows that the proposed algorithm is simple, and is superior to the P&O and IncCond methods.
Abstract: Photovoltaic (PV) energy is one of the most important renewable energy sources. Maximum Power Point Tracking (MPPT) techniques should be used in photovoltaic systems to maximize the PV panel output power by tracking continuously the maximum power point which depends on panel’s temperature and on irradiance conditions. Incremental conductance control method has been used as MPPT algorithm. The methodology is based on connecting a pulse width modulated dc/dc SEPIC converter, which is controlled by a microprocessor based unit. The SEPIC converter is one of the buck-boost converters which maintain the output voltage as constant irrespective of the solar isolation level. By adjusting the switching frequency of the converter the maximum power point has been achieved. The main difference between the method used in the proposed MPPT systems and other technique used in the past is that PV array output power is used to directly control the dc/dc converter thus reducing the complexity of the system. The resulting system has high efficiency, low cost and can be easily modified. The tracking capability has been verified experimentally with a 10 W solar panel under a controlled experimental setup. The SEPIC converter and their control strategies has been analyzed and simulated using Simulink/Matlab software.