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Underwater wireless sensor networks (UWSNs) are comprised of sensor nodes that are deployed under the water having limited battery power and other limited resources. Applications of UWSNs include monitoring the quality of the water, mine detection, environment monitoring, military surveillance, disaster prediction, and underwater navigation. UWSNs are more vulnerable to security attacks as compared to their counterparts such as wireless sensor networks (WSNs). The possible attacks in UWSNs can abrupt the operation of entire network. This research work presents the analysis of relevant research done on security-based schemes in UWSNs. The security-based schemes are categorized into five sub-categories. Each technique in each category is analyzed in detail. The major contribution in each security-based scheme along with technique used, possible future research issues and implementation tool are discussed in detail. The open research issues and future trends identified and presented in this research can be further explored by the research community. [ABSTRACT FROM AUTHOR]

Objective: To compare the patterns of coronary artery disease (CAD) between young adults <35 years of age and patients >35 years of age. Methods: The observational retrospective study was carried out in angiography department of emergency at Punjab Institute of Cardiology, Lahore between January 2020 and October 2020. Patients ≤35 years old were in Group-I whereas patients >35 years who served as controls were in Group-II. Patients with unstable angina, non-ST and ST elevation MI all were included. The patients with previous history of CAD (CABG/PCI) and angiography done for other purposes i.e., before valvular surgery or PPM implantation were excluded. Results: Out of 1268 patients, 552 were in Group-I and 716 were in Group-II. The prevalence of normal coronaries/ mild CAD was higher in Group-I i.e., 224(40.6%) than in Group-II i.e., 64 (8.9%). Single vessel disease (SVD) was comparable in both the groups 185 (33.5%) vs. 216 (30.2%). Double vessel disease and triple vessel disease (TVD) was common in Group-II and left main stem (LMS) involvement was also significantly higher in Group-II i.e., 32 (4.5%) vs. 8 (1.4%). Clot in coronary arteries with or without underlying CAD was seen more frequently in Group-I, 61(11.1%) vs. 34 (4.7%). Presence of clot was seen mostly in those patients who had moderate coronary artery disease. Conclusion: Young patients have different coronary artery disease patterns, so the management strategy must be different in this population. Majority of the young patients have non severe disease. Clot formation is commonly seen in young adults with moderate CAD. [ABSTRACT FROM AUTHOR]

The significant growth in photovoltaic (PV) energy is experienced in the last decade because of price reduction of PV modules and the revolution of PV micro inverters. High performance and reliability are the key merit to match the life time of PV and micro inverter. Multilevel micro inverters are mostly used for DC to AC power conversion, and they are divided into two types: current source inverters (CSI) and voltage source inverters (VSI). In the power industry, voltage source micro inverters are much more commonly used to convert lower DC voltages to higher AC voltages. The frequently used pulse width modulated (PWM) switching technology of DC sources introduces harmonics into the inverter output voltage during conversion. Total harmonic distortion (THD) is a measure of harmonic pollution in the power system, and it has been discovered that THD of inverter output voltage is affected by fluctuations in both DC voltages and switching angles of inverters. This study covers inverters with unequal DC sources, which is a reasonable and practical assumption. Evolutionary analysis is used to find the best DC voltages and switching angles for minimizing THD. This paper proposed a reliability and performance enhancement of micro inverter and new design has been proposed in single level and cascaded multilevel micro inverter for full irradiance and partial shading conditions. Design analysis with mathematical modeling is presented for the analysis of voltage and current ripples as well as for total harmonic distortion (THD). Two different scenarios are presented for simulations using MATLAB as tool. Results reveal that partial shading does increase the 44.01 % harmonics with cascaded inverters; however, the impact is limited as compared to single level micro inverter. [ABSTRACT FROM AUTHOR]