Enhancement in classification accuracy of motor imagery signals with visual aid: An fNIRS-BCI Study

Usman Ghafoor,Amad Zafar,M. Atif Yaqub,Keum-Shik Hong 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

One of the most promising brain activity utilized in brain-computer interface (BCI) is motor imagery (MI). Due to weak hemodynamic response (HR) signal, the achieved classification accuracies using MI are not sufficiently high. In this study, the enhancement in HR was investigated during motor imagery tasks of ball squeezing with the right hand. Brain signals in the form of concentration changes in oxy-hemoglobin (ΔHbO) and deoxy-hemoglobin (ΔHbR) from the left sensorimotor cortex were obtained using functional near-infrared spectroscopy (fNIRS). The experiment was separated in two sessions: In the first session the MI task was performed without a visual aid, and in the second session of the same task, the visual aid was provided: A video was played on a screen that showed a person continuously squeezing the ball, which can help in enhancing the imagination, thus improvement in HR. Later the features of averaged ΔHbO were used for classification. The active channels were selected on the basis of t-values and trials of those channels were mean to obtain averaged ΔHbO. Consistent with literature, imagery task with visual aid, showed increased activation in ΔHbO. Moreover, linear discriminant analysis was used to classify signals by taking the mean and peak of the averaged ΔHbO resulting in average classification accuracies of approximately 66% and 77% for MI task, with and without visual aid, respectively. These results are convincing that showed improvement in MI ability which will be useful for fNIRS-based BCI applications.

Cortical activation during voluntary and passive movement of human index finger

Usman Ghafoor,Amad Zafar,Keum-Shik Hong 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

Passive movement, motor imagery, and observation of movement have been able to activate the somatosensory and motor cortex of brain without voluntary movement. In this paper, we have investigated cortical activation in brain using a finger movement passive mode together with voluntary movement and analysis is based on within-subject design protocol. Five subjects have participated in movement of finger tasks meanwhile their brain activity is monitored using functional near-infrared spectroscopy (fNIRS). The two gamma functions are used to model the conventional hemodynamic response function (cHRF) to determine the active locations. The t-maps (brain maps) are generated for the comparison of oxy-hemoglobin (HbO) responses of both voluntary and passive movement of index finger tasks. The results have demonstrated that both movement modes activated sensorimotor areas. The neural activation pattern in voluntary execution of finger is somewhat similar to passive movement. The results of this study will help in checking whether passive movements can be able to induce suitable amount of somatosensory stimulation. Our results inveterate that the voluntary and passive movement task are strongly coupled, supporting the importance of passive tasks as a diagnostic tool in the clinical setting.

Determination of the parameters in the designed hemodynamic response function using Nelder-Mead algorithm

Amad Zafar,Usman Ghafoor,M. Atif Yaqub,Keum-Shik Hong 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

In this paper, we have investigated the use of the Nelder-Mead algorithm in determining the parameters of a designed hemodynamic response function (dHRF) instead of using fixed parameters for functional near-infrared spectroscopy (fNIRS). The hemodynamic response (HR) is supposed to be a linear combination of the baseline, the dHRF, and physiological noises (Mayer, cardiac, and respiration). The linear combination of three gamma functions is used to model the dHRF including the initial dip, the conventional HR, and the undershoot afterward. In this formulation, fifteen parameters (9 for dHRF and 6 for physiological noises) are unknown. An objective function is designed and solved using the iterative optimization Nelder-Mead algorithm to determine the unknown parameters of dHRF and physiological noises. The performance of the algorithm is tested using simulated and experimental datasets. The fNIRS experimental data were acquired from five healthy subjects during right-hand thumb finger flexion/extension tasks from the left motor cortex. The results demonstrate that inter-subject differences existed in the dHRF parameters. Therefore, it will be worthwhile to use subject-dependent dHRF parameters for a better estimation of the cortical activation using fNIRS.

Inherent irreversibility in unsteady magnetohydrodynamic nanofluid flow past a slippery permeable vertical plate with fractional-order derivative

Khan Zafar H,Makinde Oluwole D,Usman Muhammad,Ahmad Rashid,Khan Waqar A,Huang Zaitang 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.5

This study focuses on fractional-order derivatives for the unsteady flow of magnetohydrodynamic (MHD) methanol-iron oxide (CH3OH-Fe3O4) nanofluid over a permeable vertical plate. The utilization of fractional-order derivatives provides a mathematical representation of the flow model. The concluding model, consisting of a system of fractional-order transient partial differential equations, has been solved using the finite difference method, and graphical illustrations demonstrate the effects of key parameters on the flow field. Velocity and temperature profiles provide insights into nanofluid behavior. Additionally, essential quantities such as skin friction coefficient, Nusselt number, Bejan number, and entropy generation rate have been depicted graphically. Comparison with previous studies authenticates the accuracy of the anticipated model, contributing to new intuitions into MHD nanofluid flow over a permeable vertical plate. It is worth noting that the current model, incorporating fractional-order derivatives, contributes to understanding the physical characteristics of MHD CH3OH-Fe3O4 nanofluid flow over a permeable vertical plate, research that has not been extensively explored before.

Silkworm Growth and Silk Yield on Selected Supplemented/ Un-supplemented Mulberry Varieties

AKRAM, Waseem,Usman ZAFAR,이종진 한국곤충학회 2002 Entomological Research Vol.32 No.4

Sericulture has been on developing foot hills till today in Pakistan. It is for the past few years that this industry has received recognition through greater research on the nutritional aspects. Various experiments i.e., nutritional supplementation and searching alternate food plants have been on way with varying degree of success. The present approach includes the very much neglected aspect of trying mulberry varieties and working out their impact on the silkworm growth/ development and silk yield. In Pakistan three varieties of mulberry Morus alba, M. nigra and M. indica are commonly found, these were selected for the present studies and the already established mineral dose 0.2%N ±0.1% P±0.3% K±0.1% Ca±0.15% Mg±0.15% Mn was supplemented to them through dipping method. Amongst the so designed nine treatments those in which the silkworm larvae were fed on M. nigra leaves in any form /combinatiyielded best results, as the larvae in these treatments consumed more food (73.71 gm /10 larvae) and converted maximum(77.22%) of it into body matter. This improved silkworm growth, a primary parameter for increasing the over all production and resulted in better cocoon size which weighed heavier (2.43 gm/cocoon and 1.10 gm/shell) as compared to rest of the test treatments (0.67 and 0.70 gm/shell on M. alba and M. indica, respectively).

Elimination of solidification shrinkage defects in the casting of aluminum alloy

Rashid Ali,Muhammad Zafar,Tareq Manzoor,Woo-Young Kim,Muhammad Usman Rashid,Syed Zameer Abbas,Behzad Ahmed Zai,Muddassir Ali 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

In this study, the analysis is carried out to optimize in-gate position and size of riser for casting mold. The baseline size of riser for the casting of boat propeller is based on geometric modulus and thermal analysis. The riser size is analyzed with thermal-volumetric numerical calculations to predict critical fraction solid (CFS) time and temperature gradient in casting. Simulation predictions are compared with inspection results of actual castings and found good qualitative agreement. The riser reached CFS temperature well before the castings’ cross-sectional transition regions. In feeding the molten metal, the in-gate is placed where the section modulus of casting is higher. However, the tongue of sand at in-gate increases the local cooling rate, resulting in early solidification and blockage of feeding path. The increase in riser size and in-gate position results in elimination of shrinkage cavities. An optical microscopy of the casting critical region is carried out to investigate the effect of numerical measures on internal closed microporosity and microstructure morphology.

Development of a High Density Neuroimaging System Using Functional Near-Infrared Spectroscopy

M. Atif Yaqub,Amad Zafar,Usman Ghafoor,Keum-Shik Hong 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

The progress in the field of neuroscience is critical in our rapidly aging society as the fatality rate due to brain degenerative diseases is rising. Recently, functional near-infrared spectroscopy (fNIRS) has established its application in measuring the blood chromophores’ concentration changes during an activity. In this developmental study, we have introduced our lab-developed fNIRS system that is able to compute the concentration changes in oxy-hemoglobin and deoxy-hemoglobin from the optical NIR light signals. We have employed 128 dual wavelength light emitting diodes (LEDs) of 735 nm and 850 nm in the designed system. LED driving circuit was designed by using serial peripheral interface based output expansion chips. A single photodiode (PD) was used for measuring the NIR light intensity received after passing through the brain tissue and getting absorbed and scattered in the process. Our system uses a battery for supplying power to the system. A wireless communication module was interfaced with the system for transferring the fNIRS data to our developed software running on a host computer. The software is capable of displaying the real-time data and record it for future processing. To test the functionality of the system, a phantom brain model was used. The LED and PD were attached to the phantom and multiple combinations of LEDs were tested to provide robust data. Our lab-developed fNIRS system showed the acquired intensity values for both wavelengths which corresponds to hemoglobin changes in 128 channels.

Media Framing on Coverage of Motorway Rape Incident: A Study of Cable Channels in Pakistan

Muhammad Riaz Raza,Muhammad Usman Saeed,Zafar Ali 숙명여자대학교 아시아여성연구원 2023 Asian Women Vol.39 No.2

Sensitive issues, such as rape, need to be handled with special care in the media, as the media's framing impacts how the audience perceives an event. Using framing theory, this study investigated the coverage of the Lahore-Sialkot Motorway Incident on four leading news channels: Geo News, ARY News, Dunya News, and Express News. Content analysis was performed to analyze the data collected from 26 programs of 4 primetime talk shows on the selected channels. The study's findings reveal that Geo News provided the most extensive coverage of the incident. Altogether, seven significant themes were identified, the most dominant thematic frame being blaming the police. It concludes that the media's coverage of the incident was responsible and objective in relation to the victim and avoided the use of sensational language.

Natural convection effects on heat and mass transfer of slip flow of time-dependent Prandtl fluid

Muhammad Hamid,Tamour Zubair,Muhammad Usman,Zafar Hayat Khan,Wei Wang 한국CDE학회 2019 Journal of computational design and engineering Vol.6 No.4

We proposed a mathematical model for an incompressible, viscous, natural convection, and stagnation point slip flow of MHD Prandtl fluid over an infinite plate. The governing flow equations are constructed using the Prandtl rheological model. In account of physical relevance, we investigated the Soret and Dufour effects on the flow field. The complex natured flow equations are transformed to a set of PDEs using a suitable similarity variables. The non-dimensionalized ruling problem together with physical boundary conditions is numerically analyzed via Crank-Nicolson scheme. The velocity, temperature and concentration of the diffusing species distributions are enhanced for higher values of unsteadiness parameter. It is noted that velocity is slightly decreasing for higher values of Reynolds number while smaller values of Re providing more dominant effects on the velocity, temperature and concentration of the diffusing species profiles and enhanced heat and mass transfer rates is noticed. The physical behav-ior of reduced Nusselt and Sherwood numbers, friction factor, for distinct values of emerging parameters is examined and representative set of graphs are presented.

Physiological response of cotton genotypes against NaCl salt stress under solution culture

Muhammad Ibrahim,Muhammad Sajjad Haider,Usman Saleem,Saif-ur-Rehman,Kafeel Ahmad,Zafar Iqbal Khan,Muhammad Aleem Sarwar 한국토양비료학회 2011 한국토양비료학회 학술발표회 초록집 Vol.2011 No.5