Performance of channel estimation schemes in the presence of gaussian mixture model

Channel estimation (CE) plays a crucial role in establishing a wireless link, specifically at the receiver node. Most of the receivers that estimate the channel is in the presence of AWGN. However, these schemes perform expressively worse when the impulsive noise is added in AWGN which is introduced by manmade sources (pressure cooker, motorbike, electric supply) as well as natural noises (earthquakes and thundering). The major contribution of this research is to analyze the channel estimation schemes in the Gaussian mixture model (GMM) environment. The performance of channel estimation schemes has been compared in terms of mean square error (MSE) and bit error rate (BER). Four channel estimation schemes e.g., MMSE, DFT, correlation- based methods like Gauss-Seidel (GS) and Successive Over- Relaxation (SOR), are studied and analyzed. The study reveals that the correlation scheme based on the method of SOR is more effective as compared to the methods of DFT, MMSE and GS because of faster convergence rate along with the minimum number of iteration. SOR shows sustainable results up to the probability of an impulsive element of 5 Percent.Postprint (published version

Figurations of displacement in and beyond Pakistan: empirical findings and reflections on protracted displacement and translocal connections of Afghans

Pakistan currently hosts up to three million Afghans, a number that is likely to increase due to the Taliban's recent return to power in Afghanistan. This working paper is based on empirical research on the experience of Afghan displacement in Pakistan from 2019 until early 2021 as part of the European Union funded TRAFIG project. Findings show that Afghans' protracted displacement is classed. Many low-skilled, low-income and largely non-educated Afghans experience barriers to upward social mobility, particularly leading the Afghan youth to consider migrating to Europe. First-generation Afghan refugees who migrated mainly in the 1980s and 1990s prefer to stay in Pakistan; only few would return if the conditions allowed it. While aiming to incentivise return, Pakistani government policies hamper the opportunity for Afghans to move around within and beyond Pakistan and remain connected to their translocal and transnational networks. Many Afghan refugees have family members who live in other parts of Pakistan or in other countries, but the potential of these networks to lift those in Pakistan out of protracted displacement is limited. We also found that social cohesion between Afghan refugees and the Pakistani host society has been decreasing. Local networks are highly significant in day-to-day life, but intergroup relations do not yield any emancipatory potential for Afghans. Afghans' presence in Pakistan needs to be reconsidered by all actors, namely the country of origin, host and donor countries. The current approach of 'administering Afghans' keeps them in protracted displacement without the opportunity to integrate legally or sustainably. It needs to be replaced with a new narrative and operational approach - one that acknowledges Afghans' contributions to Pakistan's economy, society and culture, and that secures their right to remain in Pakistan. Such an approach is particularly important today given the looming prospect of more Afghans entering Pakistan to escape from living under a government headed by the Taliban

MONITORING SPATIOTEMPORAL AND MICRO-LEVEL CLIMATIC VARIATIONS IN LAHORE AND SUBRUBS USING SATELLITE IMAGERY AND MULTI-SOURCE DATA

This research is aimed at monitoring of spatio-temporal and micro-level climatic variations for the Lahore region. The monitoring period spans six decades from year 1950 to 2010. For accomplishing the study objectives, multi-concept satellite imageries, meteorological data and anthropogenic parameters were analyzed in detail. A set of four imagery datasets, three from Landsat sensors and one from the ASTER, were digitally processed for major land cover features. Results of digital image-classification revealed prominent variations in various landcover features, specifically in terms of increased urbanization at the expense of oxygen-rich vegetal cover in the form of previously existing agriculture activity. The analysis of meteorological data for the said period indicates an increase of 2.0oC in the average minimum temperature and decrease of 0.6oC in the average maximum temperature of Lahore. The study proposes that rapidly increasing urbanization is causing a drastic increase in the emission of CO2 and smog. The smog can be observed as dark-gray inversion layer underpinning greenhouse effect and causing increase in the minimum temperature. All these factors lead to local climate change.  Such effects are contributing towards the local climate change along with the increased urbanization, traffic density, de-vegetation and construction/ earth-moving practices. Resultantly, the use of remotely-sensed imagery and multi-source data facilitates in estimating the spatiotemporal variations in the micro-level climate. &nbsp

Comparison of Frequency of Pseudo-Exfoliation Syndrome in Patients Undergoing Cataract Surgery in Different Regional Hospitals of Pakistan

Objective: To compare the frequency of Pseudo-Exfoliation Syndrome (PXS) in patients undergoing cataract surgery in different regional hospitals in Pakistan. Study Design: Cross-sectional study. Place and Duration of Study: Three Tertiary Care Hospitals of Karachi, Rawalakot and Skardu Pakistan, from Sep 2017 to May 2020. Methodology: Patients aged 45 years and more undergoing age-related cataract surgery were evaluated for Pseudo-Exfoliation Syndrome. Initially, each patient underwent a complete outpatient ophthalmological workup. Demographic details like age and gender were noted. All the patients were screened for hypertension and diabetes mellitus. In addition, patients were screened for pseudo-exfoliation syndrome. Congenital, developmental, secondary and traumatic cataracts were excluded. Results: A total of 1882 patients were included in the study. Pseudo-exfoliation was carried out in 249(13.23%) patients. In Hospital-A, 23(3.23%); in Hospital-B, 145(14.92%) and Hospital-C, 81(40.70%) of the patients had pseudo-exfoliation. The frequency of pseudo-exfoliation syndrome was significantly more in Hospital-C and then in Hospital-B and least in HospitalA (p<0.01). Conclusion: Pseudo-exfoliation syndrome was significantly more common in Skardu and then in Rawalakot and least in Malir, which in the same order have more latitude away from the equator, have less average annual temperature and are situated at higher altitudes

A State of the Art in Simultaneous Localization and Mapping (SLAM) for Unmanned Ariel Vehicle (UAV): A Review

For the past decade, the main problem that has attracted researchers’ attention in aerial robotics is the position estimation or Simultaneous Localization and Mapping (SLAM) of Unmanned Aerial Vehicles (UAVs) where the GPS signal is poor or denied. This article reviews the strengths and weaknesses of existing methods in the field of aerial robotics. There are many different techniques and algorithms that are used to overcome the localization and mapping problem of these UAVs. These techniques and algorithms use different sensors, such as Red Green Blue-Depth (RGB_D), Light Detecting and Ranging (LIDAR), and Ultra-wideband (UWB). The most common technique is used, i.e., probability-based SLAM, which uses two algorithms: Linear Kalman Filter (LKF) and Extended Kalman Filter (EKF). LKF consists of five phases and this algorithm is just used for linear system problems. However, the EKF algorithm is used for non-linear systems. Aerial robots are used to perform many tasks, such as rescue, transportation, search, control, monitoring, and different military operations because of their vast top view. These properties are increasing their demand as compared to human service. In this paper, different techniques for the localization of aerial vehicles are discussed in terms of advantages and disadvantages, practicality and efficiency. This paper enables future researchers to find the suitable SLAM solution based on their problems; either the researcher is dealing with a linear problem or a non-linear problem

The Possible Role of Selenium Concentration in Hepatitis B and C Patients

Background/Aim: The compelling evidence reported that selenium is an essential trace mineral for human beings. Selenium plays a pivotal role in the restoration of immune functions. High rates of hepatitis B and C are present in Pakistan. Epidemiologic surveys demonstrated an inverse association between selenium (Se) level and regional cancer incidence, as well as viral infection. The present study was designed to evaluate the concentration of selenium in the serum of patients suffering from hepatitis B and C. Patients and Methods: In this cross-sectional descriptive analytical study, serum selenium concentration of 150 patients suffering from hepatitis B and C, along with 26 healthy controls, was determined by atomic absorption spectrophotometer equipped with hydride generation system, model Analytic Jena (Vario III). Results: The mean and standard deviation of serum selenium concentration observed in male and female patients with hepatitis C were 101.60±0.55 and 77.43±0.47 μ g/L, respectively, whereas the mean and standard deviation of serum selenium concentration observed in male and female patients with hepatitis B were 107.58±0.44 and 137.8±0.36 μg/L. Analysis of t test showed significant difference between C and B (P<0.001) patients in serum selenium concentration, when compared with the control. Conclusion: The obtained results indicate that serum selenium concentration of hepatitis B and C patients is less than serum selenium concentration of healthy individuals. However, serum selenium decline is relative to severity of disease. Based on findings of this study, it is proposed that selenium should be supplemented in such patients in order to optimize nutritional support and to get better treatment response