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Objective: To determine if a goal-directed ECG workshop improves ECG interpretation competency and confidence among the house officers in PNS Shifa Hospital. Study Design: Prospective comparative study. Place and Duration of Study: Pakistan Naval Ship Shifa Hospital, Karachi Pakistan, from Jan to Dec 2021. Methodology: ECG workshops were conducted for House Officers in batches. The participants were asked to complete a questionnaire testing their ECG interpretation competency before and after the workshop and self-report their confidence level in ECG interpretation. Results: Sixty-eight house officers participated in the workshops and completed the test. There were 41(60.29%) female and 27(39.7%) male participants. The statistics showed significant improvement in ECG competency (p

Brain tumours are quickly increasing in prevalence all over the world. It causes the deaths of thousands of individuals annually. Misdiagnosis of brain tumours often results in unnecessary treatment, further lowering the survival rate of the affected individuals. Prompt medical diagnosis is crucial to improve the prognosis for patients with brain tumours. Positive advancements in deep and machine learning domains have been made due to repeated achievements in supporting medical practitioners in making correct diagnoses utilizing computer-aided diagnostic tools. Deep convolutional layers are superior to conventional methods at extracting unique characteristics from target regions. In this research, initially, Gabor filter and ResNet50 were applied to accurately extract the important features of brain tumours from the MRI images dataset. Firstly, the extracted features of Gabor and ResNet50 were classified individually through SVM, and secondly, the features from both these techniques were combined and then classified through SVM. The Kaggle MRI dataset for a brain tumour was utilized in this research. It includes 7,023 Images and four classes Glioma, Meningioma, No-Tumor, and Pituitary. The results from every system were outstanding, but the best results were shown by the combined features of Gabor and ResNet50, an advanced hybrid approach with 95.73% accuracy, 95.90% precision, and 95.72% f1 score.

Objective: To compare the efficacy of Amlodipine with Captopril in the management of patients presenting to the emergency department with uncontrolled blood pressure. Study Design: Comparative prospective study. Place and Duration of Study: Emergency Department, Combined Military Hospital, Malir Pakistan, from Jul to Dec 2021. Methodology: A total of 127 individuals presenting to the Emergency Department with two readings of uncontrolled blood pressure (Systolic blood pressure ≥ 160mmHg and Diastolic blood pressure ≥90mmHg) were included. They were administered a tablet of Captopril 12.5mg per oral and a tablet of Amlodipine 10mg per oral on the turn by turn basis. Patients were observed for 3 hours and monitored for the reduction in blood. The efficacy of medication was judged based on the ability to achieve target blood pressure reduction, which was at least a 20-30% reduction in systolic blood pressure. Results: Out of 127 individuals, 65(51.2%) patients were given a tablet of Captopril 12.5mg orally, and 62(48.8%) were given a tablet of Amlodipine 10mg orally. The mean reduction in systolic blood pressure was 20.73±5.17 in all patients. In addition,target blood pressure reduction was achieved in 35(53.8%) individuals of the Captopril-Group and 33(53.2%) of the Amlodipine-Group, with a total of 68(53.5%) individuals achieving target blood pressure within 3 hours after medication. Conclusion: Both medications were efficient in achieving target blood pressure levels. However, no drug was superior to another in reducing blood pressure in an emergency.

Objective: To assess the frequency of the various medical conditions in patients presenting with altered mental status (AMS) in the Emergency Department of Pakistan Naval Ship (PNS) Shifa Hospital. Study Design: Prospective longitudinal study. Place and Duration of Study: Emergency Department, Pak Naval Ship Shifa Hospital, Karachi Pakistan from Feb-Jul 2021. Methodology: Adult patients who have presented with altered mental status (Glasgow coma scale score less than 15) or who have the diagnosis "AMS" written in their notes were included in the study. Patients were observed in the wards until a definitive diagnosis could be made. Results: Sixty patients presented with AMS at the Emergency Department of PNS Shifa, during the study period. The causes of AMS were sepsis (20, 33.33%), CVA (12, 20%), metabolic (hepatic/uremic) encephalopathy (8, 13.33%), diabetic complications (7, 11.66%), seizures (5, 8.33%), drug intoxication (4, 6.66%) and respiratory failure due to lung pathology (4,6.66%). The overall mortality rate was 20%. Conclusion: Sepsis is the most frequently encountered cause of altered mental state in emergency department patients,followed by CVA, metabolic encephalopathy, and diabetic complications.

Objectives: To study the spectrum of chronic hepatitis in haemodialysis patients. Study Design: Cross Sectional study. Setting: Kutiyanana Memon Hospital (KMH), A Tertiary Care, Charity Hospital at Karachi, Pakistan. Period: Jun 2015 to May 2020. Material & Methods: During the study period, 87 patients were followed up on and tested for hepatitis B and C virus infection. The patients were included in the study after calculation of sample size and application of inclusion and exclusion criteria. AxSYM, an enzyme-linked immunosorbent assay (ELISA)-based fast immunochromatographic technology, was used to screen the samples (Abbott Laboratories, Abbot Park, IL, USA). Hepatitis B and C prevalence was established, as well as the frequency of different sequelae such cirrhosis, encephalopathy, and hepatocellular cancer. Results: Our sample population was almost evenly split between males and females, with 44 (51%) males and 43 (59%) females. Three of the 43 females tested positive for HBV, whereas 19 (63 %) tested positive for HCV. On the other hand, in males, 11 (37 %) had chronic HCV and 9 (75 %) had Chronic HBV infection, accounting for 34% of the total HBV population. Conclusion: In haemodialysis patients, hepatitis B and C are very common. They are adding to morbidity and mortality of already suffering community. This trend is surrogate marker of suboptimal infection control techniques during dialysis in underdeveloped countries like Pakistan. To protect an already afflicted community from a potentially preventable disease, immediate measures are required for prevention and early diagnosis of chronic hepatitis.

Objective: to know the connection between Sodium intake/urinary Sodium excretion and the tendency to develop hypertension during pregnancy. Study design: Prospective longitudinal study. Place and Duration of Study: Combined Military Hospital Kharian, District Gujrat Pakistan from Jul 2019 to Dec 2020. Methodology: The included population was divided into two equal Groups (Normotensive and hypertensive). Blood pressure was measured at a pre-determined interval starting from the initial prenatal visit before 18 weeks of pregnancy to the 36th week of gestation. Urinary Sodium secretion was determined in 24-hours urine accumulated at three stages between 18 and 36 weeks of gestation. The main outcome actions were the implication of the difference in mean between urinary Sodium and alterations in maternal BP. Results: The mean age of our study population was 32 years ± 6.96 years, and it ranged from 31 to 48 years. The mean urinary sodium was 141.00 ± 24.879, 140.00 ± 29.73 and 139.00±15.17 mEq/day in the normotensive group, which was 142.00 ± 21.90, 143.00 ± 32.03 and 139.00 ± 14.27 mEq/dl in the hypertensive group. In the hypertensive group, systolic Blood pressure was also high with mean systolic BP of 143.00±12.10, 141.00±12.47 and 148.00±16.82 respectively during the three trimesters. As expected, it was normal in the second group. Conclusion: There was no significant association between sodium intake and pregnancy-induced hypertension.

Objective: To determine the exact magnitude of the problem in our setup which will help to develop consensus guidelines with the contribution from various specialists especially obstetric medical specialist. Study Design: Prospective Observational study. Setting: It was conducted on 2448 patients who were ill due to various medical conditions during pregnancy and admitted to PNS Shifa and CMH Kharian. Period: 1st Jun 2019 till 31st May 2021. Material & Methods: Data was collected from the patients in the wards and delivery room and analysed using SPSSV28. Descriptive statistics were applied and means, and frequencies were calculated for different variables. Results: The total number of antenatal admissions was 8775, in which 2488 (28%) were patients. The mean age of our study population was 28 S.D (+ 4.78) years while the mean parity was 4 (S.D + 1.407). Hypertensive disorders were the most common medical disorder followed by haematological and liver disorders. Endocrine disorders were found in 372 (15%) of the study population. A total of 864 (38%) patients in the total study population had haematological abnormalities. Among these, anaemia was the most common haematological abnormality. Regarding respiratory disorders COVID-19 336(14%) was the most common respiratory medical disorder during pregnancy. Conclusions: All medical conditions in pregnancy are common and require a multidisciplinary approach which should be managed by a team involving Obstetric medical specialist.

Objective: To compare the efficacy and safety of intravenous Insulin infusion versus subcutaneous Insulin in the management of hyperglycaemia in intensive care. Study Design: Quasi-experimental study. Place and Duration of Study: Medical Intensive Care Unit of Combined Military Hospital Malir, from Jul to Sep 2021. Methodology: 68 individuals admitted to the Medical ICU with the blood sugar levels of more than 180 mg/dl were included. Patients on one side of Intensive Care Unit were administered intravenous Insulin infusion, and on the other side were administered subcutaneous Insulin to control blood sugars. Age, gender, previous history of diabetes and use of Insulin and glycosylated haemoglobin were recorded. Efficacy of regimen was judged based on ability to achieve target glucose levels, mean blood glucose levels and total days of ICU stay. Adverse events like hypoglycaemia and hypokalaemia were recorded. Results: Out of 68 individuals, 27 (39.70%) were administered intravenous Insulin infusion, and 41 (60.29%) were administered subcutaneous Insulin. In the intravenous Insulin group, 22 (81.5%) individuals achieved target blood glucose compared to 29 (70.7%) in the subcutaneous Insulin group. The mean blood sugars in the intravenous group were 157.11 ± 25.54 mg/dl, whereas 168.32 ± 30.49 mg/dl in the subcutaneous group (p-value=0.164). The frequency of hypoglycaemia and hypokalaemia was more in the intravenous group than in the subcutaneous group. Conclusion: Optimal blood sugar levels were better achieved with intravenous Insulin than with subcutaneous Insulin. However, the frequency of adverse effects was also more with intravenous Insulin, so better monitoring and management are..............

This study presents an ultracompact dual-band bandpass filter with controllable transmission zeros based on quarter-wave dual-mode resonator for GSM (global system for mobile communications) and GPS (global positioning system) wireless applications. The filter is made up of two quarter-wave resonators, which help to independently control the passbands. A direct feed resonator creates the first operating band, which serves as a feeding source for the interior resonator and operates at a higher frequency band. Therefore, a pair of transmission zeros can be energized between the two passbands, and high roll-off skirts are obtained. To reduce the size of the entire filter, the two resonators are bent and connected together through a hole in a metal base. The structure is symmetrical in nature, so both frequency bands can be obtained using the even-odd mode analysis method. For GSM applications, the center frequency of the first working band is 850 MHz, while for GPS wireless applications, the center frequency of the second working band is 1.57 GHz. Although there is a feed line (λg is based on a waveguide length of 850 MHz), the filter has been simulated and fabricated for verification, with an ultra-compact size of 0.10 λg × 0.09 λg (0.0095 λg 2). The simulation results and measured results match well, and the theory of the design concept is recognized.

This work presents a novel microstrip patch antenna for future 5G mobile applications having resonant frequencies of 38, 47.7, 54.4 and 72GHz having bandwidth of 3, 3, 2 and 2GHz respectively. The main target frequency of over research was 38 GHz. This design is achieved using Rogers RT5880 (Lossy) substrate having standard thickness of 0.508mm with 2.2 dielectric constant and loss tangent of 0.0013. Substrate of dimensions 6 × 6mm2 and patch of dimensions 2 × 2mm2 are used in the proposed antenna design. The excitation method to energize the antenna system i.e. 1×4 and 2×2 linear array is tapered line feed with spacing of 4mm to the adjacent unit cells respectively to achieve 12dB gain for mobile applications. 3D modelling tool, the CST is used for the simulation purpose. A reasonable bandwidth, directivity and efficiency have also been achieved for the proposed design making a strong contender for competition in the market at these mm-waves frequencies. At the end SAR analysis have been performed to evaluate the antenna for possible wearable applications in the field biomedical sensors, implants and hand-held systems. The SAR values were found to be complying to the standards of FFC and CENELEC, making the design suitable for the wearable applications.

Objective: To assess the incidence and outcome of gestational diabetes mellitus (GDM) during pregnancy among sampleof Pakistani population. Study Designand Setting:This was an analytic case-control prospective study carried out at two centers (CMH Kharianand PNS Shifa Hospital Karachi) from 1st Jan till 30th July 2021. MethodologyPreviously healthy mothers were divided into three groups according to their risk of elevated glucose levelsgestational diabetes mellitus (GDM) during pregnancy. Associations between GDM eminence (exposure variable) andpregnancy-related, fetal, and neonatal outcomes were reviewed (i.e., mode of delivery, preterm baby, pregnancy-inducedhypertension, and fetal macrosomia, stillbirth, premature delivery etc. One way ANOVA was employed to compare thesignificant differences in different dependent variables amongst three groups. P Values of

In this article, compact a multiple-input and multiple-output (MIMO) system with flag-shaped radiators and a mountain-shaped ground plane is presented. Isolation is enhanced with the help of a decoupling stub placed between radiators, where two bands are stopped with the help of slits etched into the radiators. The overall size of the proposed antenna is 15 mm ×25 mm ×1.6 mm. The reflection coefficients are less than -10 dB between 3–10.9 GHz, except the bands WiMAX (3.2–3.7 GHz) and WLAN (5–6 GHz); similarly, measured and simulated transmission coefficients are less than -20 dB across the entire band of UWB. The envelope correlation coefficient (ECC) is less than 0.02 and the diversity gain is greater than 9.9 dB. The gain, ECC, radiation pattern, multiplexing efficiency, diversity gain and various other parameters are discussed and evaluated in detail.

In this article, a simple method is developed to design a highly miniaturized tri-band bandpass filter (BPF) utilizing two asymmetric coupled resonators with one step discontinuity and one uniform impedance resonator (UIR) for worldwide interoperability for microwave access (WiMAX) and radio frequency identification (RFID) applications. The first and second passbands located at 3.7 GHz and 6.6 GHz are achieved through two asymmetric coupled step impedance resonators (SIRs), while the third passband, centered at 9 GHz, is achieved using a half-wavelength UIR, respectively. The fundamental frequencies of this BPF are implemented by tuning the physical length ratio (α) and impedance ratio (R) of the asymmetric SIRs. The proposed filter is designed and fabricated with a circuit dimension of 13.69 mm × 25 mm (0.02 λg × 0.03 λg), where λg represents the guided wavelength at the first passband. The experimental and measured results are provided with good matching.

This paper presents a novel technique based on Hybrid Spatial Distance Reduction Algorithm (HSDRA), to compensate the effects of deformity and mutual coupling occurred due to surface change in conformal arrays. This antenna surface deformation shifts the position of null points and loss of the main beam resulting in reduced antenna gain along with substantial undesirable effects on the antenna performance. The proposed algorithm, which cumulatively incorporates the Linearly Constraint Least Square Optimization (LCLSO) and Quadratically Constraint Least Square Optimization (QCLSO) techniques, is formulated to minimize/reduce the absolute distance between the actual (simulated/measured) radiation pattern and the desired radiation pattern while keeping the direction of main beam and nulls position under control. In particular, a 4x4 conformal microstrip phased array from planar surface is deformed to prescribe spherical-shape surface with various radii of curvature, is validated. For the enhancement of Gain of the conformal array antenna, Gain Maximization Algorithm is also proposed, the simulated results of which is compared to the traditional Phase compensation technique and unconstraint least squares optimization. The analytical results for both planar and spherical deformed configurations are first evaluated in MATLAB and then validated through Computer Simulation Technology (CST).

Speech enhancement (SE) reduces background noise signals in target speech and is applied at the front end in various real-world applications, including robust ASRs and real-time processing in mobile phone communications. SE systems are commonly integrated into mobile phones to increase quality and intelligibility. As a result, a low-latency system is required to operate in real-world applications. On the other hand, these systems need efficient optimization. This research focuses on the single-microphone SE operating in real-time systems with better optimization. We propose a causal data-driven model that uses attention encoder-decoder long short-term memory (LSTM) to estimate the time-frequency mask from a noisy speech in order to make a clean speech for real-time applications that need low-latency causal processing. The encoder-decoder LSTM and a causal attention mechanism are used in the proposed model. Furthermore, a dynamical-weighted (DW) loss function is proposed to improve model learning by varying the weight loss values. Experiments demonstrated that the proposed model consistently improves voice quality, intelligibility, and noise suppression. In the causal processing mode, the LSTM-based estimated suppression time-frequency mask outperforms the baseline model for unseen noise types. The proposed SE improved the STOI by 2.64% (baseline LSTM-IRM), 6.6% (LSTM-KF), 4.18% (DeepXi-KF), and 3.58% (DeepResGRU-KF). In addition, we examine word error rates (WERs) using Google’s Automatic Speech Recognition (ASR). The ASR results show that error rates decreased from 46.33% (noisy signals) to 13.11% (proposed) 15.73% (LSTM), and 14.97% (LSTM-KF).

This study proposes a novel reconfigurable antenna for the millimeter-wave frequency spectrum. The proposed hybrid reconfigurable antenna is designed to reconfigure antenna parameters in compliance with wireless application specifications, such as frequency and radiation patterns. PIN Diodes as a switch are used to monitor the reconfiguration features i.e. adjusting the frequency response and radiation pattern of the antenna. For the desired goal, antenna is incorporated with three switches (S1, S2 & S3). The main beam of the antenna is guided by S1 and S2 which connects parasitic stubs H1 and H2 and the frequency is controlled by S3 between 28 and 38 GHz which connects patch P1 with P2. Proposed work is validated for 28 GHz and 38 GHz operational bands. When S3 is active (at ON state), the proposed antenna operates at 28 GHz resonant frequency with a reflection coefficient of − 32.3 dB and when S3 is in-active (at OFF state), it results in 38 GHz resonant frequency with a reflection coefficient of − 42.1 dB. RTDuroid5880 with $$\varepsilon _{{\text{r}}} = 2.33$$ , $$\tan \delta = 0.0009$$ and thickness (h) of $$0.506\,{\text{mm}}$$ and is excited through an inset feed. HFSS software is used for the simulation purpose.

In this paper, a coplanar waveguide-fed ultra-wideband-multiple-input and multiple-output (UWB-MIMO) antenna with a novel stub for isolation has been presented. The dimensions of the proposed antenna are 18 × 22 × 1.6 mm3. The proposed antenna is design on an FR4 substrate and simulated in CST studio. The |S11| of the presented MIMO antenna is less than −10 dB between 2.8 and 13 GHz with an impedance bandwidth of 10.2 GHz. The envelope correlation coefficient (ECC) is less than 0.007 and diversity gain (DG) is greater than 9.97 dB. The proposed UWB-MIMO antenna is analyzed in terms of isolation, reflection coefficient, current distribution, ECC, DG, peak gain, multiplexing efficiency, and radiation pattern.

Speech enhancement is a very important problem in various speech processing applications. Recently, supervised speech enhancement using deep learning approaches to estimate a time-frequency mask have proved remarkable performance gain. In this paper, we have proposed time-frequency masking-based supervised speech enhancement method for improving intelligibility and quality of the noisy speech. We believe that a large performance gain can be achieved if deep neural networks (DNNs) are layer-wise pre-trained by stacking Gaussian-Bernoulli Restricted Boltzmann Machine (GB-RBM). The proposed DNN is called as Gaussian-Bernoulli Deep Belief Network (GB-DBN) and are optimized by minimizing errors between the estimated and pre-defined masks. Non-linear Mel-Scale weighted mean square error (LMW-MSE) loss function is used as training criterion. We have examined the performance of the proposed pre-training scheme using different DNNs which are established on three time-frequency masks comprised of the ideal amplitude mask (IAM), ideal ratio mask (IRM), and phase sensitive mask (PSM). The results in different noisy conditions demonstrated that when DNNs are pre-trained by the proposed scheme provided a persistent performance gain in terms of the perceived speech intelligibility and quality. Also, the proposed pre-training scheme is effective and robust in noisy training data.

A novel printed and compact profile monopole antenna with hybrid reconfigurability structure for switching the resonant frequency and direction of maximum radiations is proposed in this research work. A novel mathematical model for the architecture of Reconfigurable Patch Antenna (RPA), considering input impedance, bandwidth, antenna gain, antenna efficiency and resonant frequency is proposed. For the desired functionality, antenna is incorporated with three switches in such a way that Switch 1 and Switch 2 direct the radiation beam patterns towards different directions while Switch 3 controls the frequency reconfigurability. When Switch 3 is ON, the designed antenna operates at 26.4 GHz covering the 24.2–26.5 GHz band. When Switch 3 is OFF, it operates at 28 GHZ, covering the 27.4–29.8 GHz band. The antenna is proposed to operate at the 5G mobile communication band having a center frequency at 27.6 GHz with a reflection coefficient of −21.5 dB. A 3D design tool HFSS has been used for the simulation purposes.

Speech-in-noise perception is an important research problem in many real-world multimedia applications. The noise-reduction methods contributed significantly; however rely on a priori information about the noise signals. Deep learning approaches are developed for enhancing the speech signals in nonstationary noisy backgrounds and their benefits are evaluated for the perceived speech quality and intelligibility. In this paper, a multi-objective speech enhancement based on the Long-Short Term Memory (LSTM) recurrent neural network (RNN) is proposed to simultaneously estimate the magnitude and phase spectra of clean speech. During training, the noisy phase spectrum is incorporated as a target and the unstructured phase spectrum is transformed to its derivative that has an identical structure to corresponding magnitude spectrum. Critical Band Importance Functions (CBIFs) are used in training process to further improve the network performance. The results verified that the proposed multi-objective LSTM (MO-LSTM) successfully outscored the standard magnitude-aware LSTM (MA-LSTM), magnitude-aware DNN (MA-DNN), phase-aware DNN (PA-DNN), magnitude-aware GNN (MA-GNN) and magnitude-aware CNN (MA-CNN). Moreover, the proposed speech enhancement considerably improved the speech quality, intelligibility, noise-reduction and automatic speech recognition in changing noisy backgrounds, which is confirmed by the ANalysis Of VAriance (ANOVA) statistical analysis.

Machine learning-based supervised single-channel speech enhancement has achieved considerable research interest over conventional approaches. In this paper, an extended Restricted Boltzmann Machine (RBM) is proposed for the spectral masking-based noisy speech enhancement. In conventional RBM, the acoustic features for the speech enhancement task are layerwise extracted and the feature compression may result in loss of vital information during the network training. In order to exploit the important information in the raw data, an extended RBM is proposed for the acoustic feature representation and speech enhancement. In the proposed RBM, the acoustic features are progressively extracted by multiple-stacked RBMs during the pre-training phase. The hidden acoustic features from the previous RBM are combined with the raw input data that serve as the new inputs to the present RBM. By adding the raw data to RBMs, the layer-wise features related to the raw data are progressively extracted, that is helpful to mine valuable information in the raw data. The results using the TIMIT database showed that the proposed method successfully attenuated the noise and gained improvements in the speech quality and intelligibility. The STOI, PESQ and SDR are improved by 16.86%, 25.01% and 3.84dB over the unprocessed noisy speech.

A novel three-mode step impedance resonator (TSIR) is developed to design a miniaturized multi-pole microstrip planar ultra-wideband (UWB) filter with independently controlled notched bands at different frequencies is presented in this work. The basic UWB filter consists of four L-shaped λ/4 short-circuited stubs operating in the range of i.e. 2.7 to 12.1 GHz with fractional bandwidth (FBW) 127%, and the TSIR is constructed using two T-shaped λ/2 open ended step impedance resonator (SIR) and one λ/4 short-circuited uniform impedance resonator (UIR) is coupled to the basic UWB design in order to achieve the stopbands performance at 5.1 GHz, 6 GHz, and 8 GHz, to supress the unwanted bands of WLAN, Wi-Fi 6E, and X-band satellite communication system, respectively. Commercial full-wave electromagnetic (EM) software HFSS-13 was used to design an ultra-compact structure having size 0.07 λg×0.02 λg on Rogers RT/Duroid 5880 substrate to justify good agreement between simulated and measured S-parameters.

Reconfigurable antennas have received much attention in RF energy harvesting models owing to their selectivity for operating frequency and polarization. The characteristic of having frequency selectivity and polarization selectivity can be termed as frequency diversity and polarization diversity, respectively. This paper investigates a rectenna device with a new proposed topology in order to eliminate coupling between input and output lines and increase the rectification efficiency with the use of single feed hybrid reconfigurable antenna, switch between 28GHz and 38GHz frequency. Moreover, it is designed to charge a rechargeable battery of 1watt(W). The Reconfiguration mechanism is realized by electronically controlling different states of Switches. PIN Diode (as RLC Equivalent circuit) is used as a switch for ON/OFF states. This antenna mainly comprises rectangular shaped patches (28GHz and 38GHz) with Triango-Truncated edge at the corners. Eighteen PIN Diodes are placed symmetrically throughout the antenna presenting as, S1 & S2 for frequency reconfiguration, S3 to S6 & S7 to S10 connects Triango Truncated edge at the corners for polarization reconfiguration, and for radiation pattern reconfiguration at S11 to S14 & S15 to S18 has been used. The proposed antenna model is capable of simultaneously changing, the radiation patterns as clock and anti-clockwise directions at ±90-degree shift in E and H planes, circularly polarized (CP) states among, Linear Polarization (LP), Right Hand Circularly Polarization (RHCP), and Left Hand Circularly Polarization (LHCP). The current design describes using single antenna for energy harvesting and 5G mobile communication application. This would lead to higher output currents, leading to the ability to efficiently charge a wide variety of batteries. A fully functional prototype has been designed, fabricated and its compound reconfiguration characteristics have been validated for simulated and measured results. For validation of results, the experimental results and the simulation results from the proposed mathematical model were made into comparison, and excellent correlation between the measured and simulated results was obtained.

Reducing interfering noise in a noisy speech recording has been a difficult task in many applications related to the voice. From hands-free communication to human–machine interaction, a speech signal of the interest captured by a microphone is always mixed with the interfering noise. The interfering noise appends new frequency components and masks a large portion of the time-varying spectra of the desired speech. This significantly affects our perception of the desired speech when listening to the noisy observations. Therefore, it is extremely desirable and sometimes even crucial to clean the noisy speech signals. This clean-up process is referred to as the speech enhancement (SE). SE aims to improve the speech intelligibility and quality of the voice for the communication. We present a comprehensive review on the supervised single channel speech enhancement (SCSE) algorithms. First, a classification based overview of the supervised SCSE algorithms is provided and the related works is outlined. The recent literature on the SCSE algorithms in supervised perspective is reviewed. Finally, some open research problems are identified that need further research.

Channel state information (CSI) feedback in massive MIMO systems is too large due to large pilot overhead. It is due to the large channel matrix dimension which depends on the number of base station (BS) antennas and consumes the majority of scarce radio resources. To solve this problem, we proposed a scheme for efficient CSI acquisition and reduced pilot overhead. It is based on the separation mechanism for the channel matrix. The spatial correlation among multiuser channel matrices in the virtual angular domain is utilized to split the channel matrix. Then, the two parts of the matrix are estimated by deploying the compressed sensing (CS) techniques. This scheme is novel in the sense that the user equipment (UE) directly transmits the received symbols from the BS to the BS, so a joint CSI recovery is performed at the BS. Simulation results show that the proposed channel estimation scheme effectively estimates the channel with reduced pilot overhead and improved performance as compared with the state-of-the-art schemes.

Variance based two dimensional time-frequency mask estimation for unsupervised speech enhancement is proposed to improve the speech quality and intelligibility by reducing the low-frequency residual noise distortion in the noisy speech signals. Unlike conventional speech enhancement methods, the proposed method is able to reduce the residual noise distortion by utilizing benefits of the less aggressive Wiener gain and variance based two dimensional time-frequency mask to establish a two-stage speech enhancement method. In the first stage, the less aggressive Wiener gain with modified a priori signal-to-noise (SNR) estimate is applied to the input noisy speech to obtain a reduced noise pre-processed speech signal. In the second stage, variance based features are extracted from the pre-processed speech and compared to a nonparametric adaptive threshold to construct a two dimensional time-frequency mask. The estimated mask is then applied to the pre-processed speech from the first stage to suppress the annoying residual noise distortion. A comparative performance study is included to demonstrate the effectiveness of the proposed method in various noisy conditions. The experimental results showed large improvements in terms of the perceptual evaluation of speech quality (PESQ), segmental SNR (SegSNR), residual noise distortion (BAK) and speech distortion (SIG) over that achieved with competing methods at different input SNRs. To measure the understanding of enhanced speech in different noisy conditions, short-time intelligibility prediction (STOI) is used which reinforced a better performance of the proposed method in terms of the speech intelligibility. The time-varying spectral analysis validated significant reduction of the residual noise components in the enhanced speech.

The Federal Communication Commission (FCC) has authorized the use of unlicensed ultra-wide band (UWB) spectrum in the frequency range from 3.1 to 10.6 GHz for a variety of short-range applications, including wireless monitors and printers, camcorders, radar imaging, and personal area networks (PANS). However, the interference between coexisting narrowband channels and UWB signals that share the same spectrum should be avoided by designing UWB antennas with band notch characteristics. This work presents a printed monopole antenna (PMA) with slots of different shapes etched in the radiating element to obtain band rejection in the three coexisting communication bands, i.e., Worldwide Interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN), and International Telecommunication Union (ITU). A rectangular slot is etched to reject the WiMAX band (3.01-3.68 GHz), an upturned C slot stops the WLAN band (5.18-5.73 GHz) while an inverted-U slot halts the ITU frequency band (7.7-8.5 GHz). The proposed antenna occupies a volume of 32 x 30 x 1.6 mm3 and it radiates efficiently (>90%) with a satisfactory gain (>1.95 dBi) in the unnotched UWB frequency range. The simulations are performed in High Frequency System Simulator (HFSS), while the measurements are conducted in antenna measurement facility and found in close agreement with the former.

All antennas in which frequency and radiation patterns can be modified in a reversible and controlled manner are known as reconfigurable antennas. They are different from other antennas, as their mechanism of reconfiguration is located within the antenna and not controlled by an external beam. For reconfigurable antennas, the potential is not to increase the performance of the antenna in a significantly changed state or to meet the needs of dynamics and efficacy. This study will discuss various aspects related to antennas that are frequency-reconfigurable, their applications and execution frequencies, change in polarization, and changes in far-field patterns or operating frequencies to better deal with changing system parameters. For the reconfigurable antennas in this paper, some past and recent applications will be reviewed, along with examples of their implementation. The arrays and moving mechanical parts are explained, along with recently introduced semiconductor factors, and the tunable material technologies that should be applicable for reconfigurable antennas.

Inherently UWB (Ultra Wideband) communication systems comes with interference problem with some if the existing narrowband communication systems. These bands are stopped with the help of band-stop filter in order to reduce electromagnetic interference However, the complexity and limitations are increased due to these filters, hence this solution is turned down in those applications where design complications and complexity is of concern. Introducing various slots of specific shapes and exact dimensions however, have solved this issue for the researchers around the world. This paper presents a hexagonal PMA (Printed Monopole Antenna) with triple stop bands. The antenna is used for UWB application. The antenna is stopped the WiMAX (Worldwide Interoperability for Microwave Access), WLAN (Wireless Local Area Network) and ITU (International Telecommunication Union) bands. The antenna dimensions are 30x28x16 mm3. FR4 is used between ground and radiating patch with relative permittivity of 4.4. The VSWR (Voltage Standing Wave Ratio) is less than 2 between 3-11 GHz except WiMAX (3.1-3.7 GHz), WLAN (5.1-5.8 GHz) and the ITU frequency band (7.95-8.4 GHz). The antenna is design in CST software.

This paper presents the results of simulation and experimental investigations on a locally fabricated patch antenna using a high dielectric ceramic (alumina) substrate. The antenna was designed for a centre frequency of 6.32 GHz within C-Band which was excited using micro-strip line feed. The bandwidth of the simulated antenna was achieved as 66.1 MHz with a return loss of 21.7 dB at the centre resonant frequency. The observed resonance frequency at the centre was found to be 6.32 GHz with a return loss of 37.55 dB for the locally fabricated antenna. The -10 dB bandwidth of the fabricated design was determined as 251 MHz. Impedance presented at central frequency was 51.2 ohm that indicates an outstanding impedance-matching between antenna and feed line. The obtained results indicate that the fabricated antenna is suitable for its applications in C-band.

A crucial stage in unsupervised speech enhancement algorithm is the estimation of noise related parameters which usually needs prior models for noise. However, estimation of such parameters is a challenging task at low signal-to-noise ratios or in nonstationary noisy environments. In this paper, without knowing the prior models, an unsupervised and iterative speech enhancement algorithm is proposed which assumes speech spectrogram and its temporal gradient as sparse components. The quasi-harmonic description of the speech signals justifies this assumption. The speech enhancement is performed by decomposing the spectrogram of noisy speech into sparse matrix, enforcing the sparsity and temporal gradient regularizations. The Kullback–Leibler divergence is incorporated to minimize the distance between the observation and reconstructed components with nonnegativity constraints. Alternating direction method of multipliers is used to optimize the algorithm. The proposed algorithm is different from many speech enhancement approaches as it reduces background noise in an uncomplicated manner without need of a noise estimation algorithm to find noise-only excerpt. In addition, the proposed algorithm obtains an improved performance in adverse environments without knowing the exact distribution of noise. The experimental results demonstrate that the proposed algorithm outperforms the competing algorithms in terms of the speech quality and intelligibility. Moreover, the composite objective measure reinforced better performance in terms of residual noise and speech distortion in strong noise.

Time-frequency masking combined with spectral phase estimation may be useful for recovering the intelligibility and quality of speech degraded by background noises. This unsupervised speech enhancement method has an immense ability to decrease the noise in nonstationary and difficult noisy backgrounds. The proposed method replaces the spectral phase of noisy speech with an estimated spectral phase and merges with the novel time-frequency mask during signal reconstruction. Variance-based features are extracted to estimate the time-frequency mask and are then passed over an unsupervised and nonparametric adaptive threshold. The extracted features satisfying the threshold condition are retained, whereas the violating features are discarded. The estimated time-frequency mask is used to obtain enhanced speech. During phase estimation for signal reconstruction, the noisy phase is decomposed into the spectrum of the instantaneous noisy phase trailed by temporal smoothing to decrease variations. Results show considerable improvements in terms of short-time objective intelligibility (STOI), perceptual evaluation of speech quality (PESQ), segmental signal-to-noise ratio (SSNR), and speech distortion.

In this paper, a half-circular disc PMA (Printed Monopole Antenna) for SWB (Super Wide Band) applications is presented. The dimensions of the substrate is 40x40x1.7mm. The antenna is printed on Rogers RT5880 dielectric material. The antenna VSWR (Voltage Standing Wave Ratio) has less than 2 between 2.7 and 50 GHz. The antenna S11 has less than -10 between 2.7 and 50GHz. The antenna has a maximum gain of 12.4dBi. The BW (Bandwidth) of the proposed antenna is about 47.3 GHz. The antenna covered the WiMAX ((Worldwide Interoperability for Microwave Access), WLAN (Wireless Local Area Network), X band, Ka band, Ku band, 4G band, and the band of 5G (Fifth Generation) at the same time with nice gain and radiation efficiency. The radiator of the proposed antenna designs from a half-circular disc, rectangle, and triangle. The antenna has a partial ground plane. Three slots are etched in the ground plane for better impedance matching, two are circular slots and one is the rectangular slot. The antenna design is simulated in CST microwave studio 2016. The antenna has good radiation efficiency, other parameters such as VSWR S11, gain, and radiation pattern are discussed in detail.

Recently machine learning based speech enhancement approaches have shown immense promise to improve the intelligibility of noisy speech for both normal hearing and hearing impaired listeners. In this paper we study speech intelligibility potential of the single-microphone speech enhancement based on Deep Neural Networks (DNNs), a part of machine learning family. We have shown that DNN based speech enhancement approach, once trained purposely to handle many types of noise and signal-to-noise ratios (SNRs), shown immense potential of attaining large speech intelligibility improvements. The deep neural network models are trained to learn mapping from the noisy speech features and the coefficients of ratio time-frequency masks are estimated. The estimated masks are applied to noisy speech magnitude spectra in order to attain an enhanced intelligibility speech by utilizing the phase of noisy speech. The results at many different noisy conditions including exhibition hall, coffee shop, airport, car and babble and five SNRs: −10dB, −5dB, 0dB, 5dB and 10dB reported that deep neural network-based ratio mask outperformed the competing methods including Nonnegative matrix factorization (NMF) and log minimum mean square error (LMMSE) estimation in terms of the short time objective intelligibility (STOI) and Normalized subband envelope correlation (NSEC) objective speech intelligibility metrics.

With the advancement of world to 5th Generation cellular communication system presently commercial implementation of 5G in USA, UK, Switzerland, South Korea and Spain a space for improvement of radiation characteristics is always there for Antenna to accommodate the high gain demands of 5G. In this paper the design and simulation of compact, millimeter wave antenna array for 5G wireless communication network is proposed operating at 30 GHz and 50 GHz. Ka band from 26GHz to 42 GHz and V band from 40GHz to 75GHz need dual band frequency for its application from a single antenna. A conventional patch antenna with dimension 3×3 mm2 is designed on Rogers RT5880LZ substrate material with thickness of 0.787 mm. Two Rectangular and one circular slot is made in the patch to attain another band at 50 GHz frequency. In this proposed antenna array configuration of 2×1 met the requirement s of improved radiation characteristics. In this proposed antenna array configuration meets the commercial demands such as 75 ohm coax cable and substrate material with thickness of 0.787mm. The realized gain of 10.2 dB & 11.6 dB and return loss value of −12.5 & −14.85 at 30 GHz and 50 GHz respectively is achieved. The bandwidth is 2.093 GHz and 1.764 GHz at 30GHz and 50GHz Respectively. The VSWR value measured from simulation is 1.67 and 1.43 at dual bands frequency which is less than 2. The proposed antenna is fed by corporate feed network technique.

A speech enhancement (SE) technique improves the quality and intelligibility of the noise degraded speech. The conventional MMSE-based SE technique minimizes the Bayesian cost function by modifying the magnitude-spectra, whereas keeping the phase-spectra intact. In this current study, both magnitude and phase spectra are modified in order to enhance the noisy speech using a phase compensated perceptually weighted β-order Bayesian estimator. In the proposed SE technique, we first modified the phase of noisy speech spectra alone. Secondly, we used perceptually motivated β-order Bayesian estimator to modify the magnitude-spectra. The estimator holds the advantages of the perceptually-weighted and the β-order spectral amplitude estimator to get a better gain function. The compensated phase spectra and the estimated magnitude spectra are combined to reconstruct the noise attenuated enhanced speech signals. The proposed speech enhancement technique is evaluated for different noise levels (0 dB to +10 dB) in terms of the objective quality and intelligibility measures using the NOIZEUS and AURORA databases. It is observed that the proposed enhancement technique considerably improves the quality and maintains intelligibility in non-stationary and stationary noisy environments. The experimental results show that the average short-time objective intelligibility (STOI), normalized covariance metric (NCM), perceptual evaluation of speech quality (PESQ), segmental SNR (SegSNR), and Likelihood-Ratio (LLR) are improved by 12.2%, 9.25%, 19.69%, 31.25%, and 39.06% over the noisy unprocessed speech signals. The proposed technique also outscored the competing techniques.

Nano photonics is empowering the advancement of gadgets in a scale running from one to couple hundred of nanometers. Indeed, Graphene nanoantenna having nanoscale size to few micrometers enabling to operate at terahertz frequencies. Graphene is highly characterized by its surface conductivity which can be derived by using Kubo’s formula. Furthermore, the scattering response of the supporting surface plasmon waves at terahertz region bring the best possible choice of nanoantenna dimensions. In this article, a graphene-based bowtie circular array antenna is proposed and analyzed at terahertz frequencies. The investigated array antenna having 8 radiating graphene unit cell arranged in circular array configuration and is designed on a stacked substrate by stacking silica on silicon having thickness of 70 nm and 50 nm respectively with the ground plane used as graphene sheet. Simulation results show that antenna has surface plasmon resonance (SPR) at infrared frequency 590 THz having S11 of -35 dB with better surface conductivity and high electron mobility. Various parametric results illustrate that the antenna has better gain and stable radiation patterns. The best achieved performance of the proposed graphene array antenna with better properties make it potential applicant for terahertz energy harvesting. CST studio (Computer Simulation Technology) is used for the simulation of the proposed antenna.

Multiband high gain antennas are the essence of future wireless communication networks. This paper presents a detailed investigation and design of 1×4 linear and 2×2 planar array antennas. Arrays are designed using Rogers RT/duroid5880 (lossy) substrate. Thickness, dielectric constant and tangent loss of the substrate are 0.508 mm, 2.2 and 0.0013 respectively. Both arrays are multiband antennas and have resonance frequencies in K band, Ka band and V band. The maximum and minimum gains of 14.22dB and 9.9dB are achieved at 44.8 GHz and 67.8 GHz using linear array. The highest gain of planar antenna is 12.34dB at 29GHz and lowest gain of 8.5 dB is obtained at 38GHz. Radiation efficiency of both antennas are in the range of 90% at all the resonance frequencies. Results of both arrays show that array with linear setup have better gain than array of planar setup whereas bandwidth and return loss of planar array is better than linear array.