Neural Correlates of Urinary Retention in Lateral Medullary Infarction

Appaswamy Thirumal Prabhakar,Atif Shaikh Iqbal Ahmed,,Aditya Vijayakrishnan Nair,Vivek Mathew,Sanjith Aaron,Ajith Sivadasan,Mathew Alexander 대한배뇨장애요실금학회 2019 International Neurourology Journal Vol.23 No.3

Purpose: The brainstem plays an important role in the control of micturition, and brainstem strokes are known to present with micturition dysfunction. Micturition dysfunction in cases of lateral medullary infarction (LMI) is uncommon, but often manifests as urinary retention. In this study, we investigated the neuro-anatomical correlates of urinary retention in patients with LMI. Methods: This was a hospital-based retrospective study conducted in the neurology unit of a quaternary-level teaching hospital. Inpatient records from January 2008 to May 2018 were searched using a computerized database. Cases of isolated LMI were identified and those with micturition dysfunction were reviewed. MRI brain images of all patients were viewed, and individual lesions were mapped onto the Montreal Neurological Institute (MNI) space manually using MRIcron. Nonparametric mapping toolbox software was used for voxel-based lesion-symptom analysis. The Liebermeister test was used for statistical analysis, and the resultant statistical map was displayed on the MNI template using MRIcron. Results: During the study period, 31 patients with isolated LMI were identified. Their mean age was 48 years and 28 (90%) were male. Six of these patients (19%) developed micturition dysfunction. All 6 patients had urinary retention and 1 patient each had urge incontinence and overflow incontinence. In patients with LMI, the lateral tegmentum of the medulla showed a significant association with urinary retention. Conclusions: In patients with isolated LMI, we postulate that disruption of the descending pathway from the pontine micturition centre to the sacral spinal cord at the level of the lateral tegmentum results in urinary retention.

Formal Reliability Analyses of Power Line Communication Networkbased Control in Smart Grid

Riaz Uddin,Syed Atif Naseem,Zafar Iqbal 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.12

Communication network is one of the primary elements of the Smart Grid for sending and receiving the bi-directional flows of important information such as load flow, faults, etc., in a reliable and efficient way. In this regard, G3-Power Line Communication (PLC) network is the most ideal preference over wireless or wired communication technology due to low cost, high throughput and better reliability for the distribution network of Smart Grid. This fact motivated us to study and analyze in detail the accuracy and reliability of the flow of information of the PLC network in terms of probabilities especially for Fault Detection, Isolation and Supply Restoration (FDIR) behavior in the distribution system of Smart Grid through formal analyses. In order to perform the analyses, first we develop the Markovian model of the FDIR behavior with (G3-PLC) in the distribution network of Smart Grid of the practical intelligent distribution network system case study, and then formally verify the model via probabilistic model checker (PRISM) tool in order to analyze the system accuracy, efficiency, and reliability by developing the logical properties and finding the success/failure probabilities for the FDIR mechanism at the occurrence of faults. Finally, some important discussions are made comparing FDIR connected with Ethernet communication network against FDIR connected with the PLC network.

MRAS Based Sensorless Control of a Series-Connected Five-Phase Two-Motor Drive System

Khan, M. Rizwan,Iqbal, Atif The Korean Institute of Electrical Engineers 2008 Journal of Electrical Engineering & Technology Vol.3 No.2

Multi-phase machines can be used in variable speed drives. Their applications include electric ship propulsion, 'more-electric aircraft' and traction applications, electric vehicles, and hybrid electric vehicles. Multi-phase machines enable independent control of a few numbers of machines that are connected in series in a particular manner with their supply being fed from a single voltage source inverter(VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases more than or equal to five-phase. The number of series-connected machines is a function of the phase number of VSI. Theoretical and simulation studies have already been reported for number of multi-phase multi-motor drive configurations of series-connection type. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information concerning the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an MRAS estimator based sensorless control of a vector controlled series-connected two-motor five-phase drive system with current control in the stationary reference frame. Results, obtained with fixed-voltage, fixed-frequency supply, and hysteresis current control are presented for various operating conditions on the basis of simulation results. The purpose of this paper is to report the first ever simulation results on a sensorless control of a five-phase two-motor series-connected drive system. The operating principle is given followed by a description of the sensorless technique.

MRAS Based Sensorless Control of a Series-Connected Five-Phase Two-Motor Drive System

M. Rizwan Khan,Atif Iqbal 대한전기학회 2008 Journal of Electrical Engineering & Technology Vol.3 No.2

Multi-phase machines can be used in variable speed drives. Their applications include electric ship propulsion, 'more-electric aircraft' and traction applications, electric vehicles, and hybrid electric vehicles. Multi-phase machines enable independent control of a few numbers of machines that are connected in series in a particular manner with their supply being fed from a single voltage source inverter (VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases more than or equal to five-phase. The number of series-connected machines is a function of the phase number of VSI. Theoretical and simulation studies have already been reported for number of multi-phase multi-motor drive configurations of series-connection type. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information concerning the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an MRAS estimator based sensorless control of a vector controlled series-connected two-motor five￢phase drive system with current control in the stationary reference frame. Results, obtained with fixed￢voltage, fixed-frequency supply, and hysteresis current control are presented for various operating conditions on the basis of simulation results. The purpose of this paper is to report the first ever simulation results on a sensorless control of a five-phase two-motor series-connected drive system. The operating principle is given followed by a description of the sensorless technique.

Characterization and Comparative Evaluation of Milk Protein Variants from Pakistani Dairy Breeds

Iqra Yasmin,Rabia Iqbal,Atif Liaqat,Wahab Ali Khan,Muhamad Nadeem,Aamir Iqbal,Muhammad Farhan Jahangir Chughtai,Syed Junaid Ur Rehman,Saima Tehseen,Tariq Mehmood,Samreen Ahsan,Saira Tanweer,Saima Naz 한국축산식품학회 2020 한국축산식품학회지 Vol.40 No.5

The aim of study was to scrutinize the physicochemical and protein profile of milk obtained from local Pakistani breeds of milch animals such as Nilli-Ravi buffalo, Sahiwal cow, Kajli sheep, Beetal goat and Brela camel. Physicochemical analysis unveiled maximum number of total solids and protein found in sheep and minimum in camel. Buffalo milk contains the highest level of fat (7.45%) while camel milk contains minimum (1.94%). Ash was found maximum in buffalo (0.81%) and sheep (0.80%) while minimum in cow’s milk (0.71%). Casein and whey proteins were separated by subjecting milk to isoelectric pH and then analyzed through sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed heterogeneity among these species. Different fractions including αS1, αS2, κ-casein, β-casein and β-lactoglobulen (β-Lg) were identified and quantitatively compared in all milk samples. Additionally, this electrophoretic method after examining the number and strength of different protein bands (αS1, αS2, β- CN, α-LAC, BSA, and β-Lg, etc.), was helpful to understand the properties of milk for different processing purposes and could be successfully applied in dairy industry. Results revealed that camel milk was best suitable for producing allergen free milk protein products. Furthermore, based on the variability of milk proteins, it is suggested to clarify the phylogenetic relationships between different cattle breeds and to gather the necessary data to preserve the genetic fund and biodiversity of the local breeds. Thus, the study of milk protein from different breed and species has a wide range of scope in producing diverse protein based dairy products like cheese.

Novel Wavelet-Fuzzy Based Indirect Field Oriented Control of Induction Motor Drives

Febin Daya J. L.,Subbiah V.,Atif Iqbal,Sanjeevikumar Padmanaban 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4

This paper presents a wavelet-fuzzy based controller for indirect field oriented control of three-phase induction motor drives. The discrete wavelet transform is used to decompose the error between the actual speed and the command speed of the induction motor drive into different frequency components. The transformed error coefficients along with the scaling gains are used for generating the control component of the motor. Self-tuning fuzzy logic is used for online tuning of the scaling gains of the controller. The proposed controller has the ability to meet the speed tracking requirements in the closed loop system. The complete indirect field oriented control scheme incorporating the proposed wavelet-fuzzy based controller is investigated theoretically and simulated under various dynamic operating conditions. The simulation results are compared with a conventional proportional integral controller and a fuzzy based controller. The speed control scheme incorporating the proposed controller is implemented in real time using a digital processor control board. Simulation and experimental results validate the effectiveness of the proposed controller.

Control and Modulation of Three to Asymmetrical Six-Phase Matrix Converters based on Space Vectors

Mohammed A. Al-Hitmi,Khaliqur Rahman,Atif Iqbal,Nasser Al-Emadi 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

This paper proposes the modulation and control of a three-to-six-phase matrix converter with an asymmetrical six-phase output. The matrix converter (MC) outputs consist of two sets of three-phase spatially shifted by 300, where the two sets have two isolated neutrals. The space vector approach is considered for the modeling and subsequent modulation of the three-to-six phase MC. The intelligent selection of voltage space vectors is made to synthesize the reference voltages and to obtain a sinusoidal output. The dwell times of selected voltage space vectors are adjusted in such a way that the effect of the second and the third auxiliary plane vectors (i.e., x1-y1, and x2-y2) are nullified. To achieve the maximum output voltage gain and to ensure that no reactive power is drawn from the utility supply, the input side power factor is maintained at unity. Nevertheless, the source side power factor is controllable. The modulation technique is implemented in dSPACE working in conjunction with a FPGA. Hardware results that validate the proposed control algorithm are discussed.

Control and Modulation of Three to Asymmetrical Six-Phase Matrix Converters based on Space Vectors

Al-Hitmi, Mohammed A.,Rahman, Khaliqur,Iqbal, Atif,Al-Emadi, Nasser The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

This paper proposes the modulation and control of a three-to-six-phase matrix converter with an asymmetrical six-phase output. The matrix converter (MC) outputs consist of two sets of three-phase spatially shifted by $30^0$, where the two sets have two isolated neutrals. The space vector approach is considered for the modeling and subsequent modulation of the three-to-six phase MC. The intelligent selection of voltage space vectors is made to synthesize the reference voltages and to obtain a sinusoidal output. The dwell times of selected voltage space vectors are adjusted in such a way that the effect of the second and the third auxiliary plane vectors (i.e., x1-y1, and x2-y2) are nullified. To achieve the maximum output voltage gain and to ensure that no reactive power is drawn from the utility supply, the input side power factor is maintained at unity. Nevertheless, the source side power factor is controllable. The modulation technique is implemented in dSPACE working in conjunction with a FPGA. Hardware results that validate the proposed control algorithm are discussed.

Sliding Mode Control Based DTC of Sensorless Parallel-Connected Two Five-Phase PMSM Drive System

Tounsi Kamel,Djahbar Abdelkader,Barkat Said,M. Al-Hitmi,Atif Iqbal 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

This paper presents a sensorless direct torque control (DTC) combined with sliding mode approach (SM) and space vector modulation (SVM) to achieve mainly a high performance and reduce torque and flux ripples of a parallel-connected two five-phase permanent magnet synchronous machine (PMSM) drive system. In order to increase the proposed drive robustness and decrease its complexity and cost, the rotor speeds, rotor positions, fluxes as well as torques are estimated by using a sliding mode observer (SMO) scheme. The effectiveness of the proposed sliding mode observer in conjunction with the sliding mode control based DTC is confirmed through the application of different load torques for wide speed range operation. Comparison between sliding mode control and proportional integral (PI) control based DTC of the proposed two-motor drive is provided. The obtained speeds, torques and fluxes responses follow their references; even in low and reverse speed operations, load torques changes, and machines parameters variations. Simulation results confirm also that, the ripples of the torques and fluxes are reduced more than 3.33% and 16.66 %, respectively, and the speed overshoots and speed drops are reduced about 99.85% and 92.24%, respectively.

Sliding Mode Control Based DTC of Sensorless Parallel-Connected Two Five-Phase PMSM Drive System

Kamel, Tounsi,Abdelkader, Djahbar,Said, Barkat,Al-Hitmi, M.,Iqbal, Atif The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

This paper presents a sensorless direct torque control (DTC) combined with sliding mode approach (SM) and space vector modulation (SVM) to achieve mainly a high performance and reduce torque and flux ripples of a parallel-connected two five-phase permanent magnet synchronous machine (PMSM) drive system. In order to increase the proposed drive robustness and decrease its complexity and cost, the rotor speeds, rotor positions, fluxes as well as torques are estimated by using a sliding mode observer (SMO) scheme. The effectiveness of the proposed sliding mode observer in conjunction with the sliding mode control based DTC is confirmed through the application of different load torques for wide speed range operation. Comparison between sliding mode control and proportional integral (PI) control based DTC of the proposed two-motor drive is provided. The obtained speeds, torques and fluxes responses follow their references; even in low and reverse speed operations, load torques changes, and machines parameters variations. Simulation results confirm also that, the ripples of the torques and fluxes are reduced more than 3.33% and 16.66 %, respectively, and the speed overshoots and speed drops are reduced about 99.85% and 92.24%, respectively.