Search

In recent times, photovoltaic (PV) power generation has been growing due to increase in energy demand. In grid-connected mode, achieving maximum power (MP) from the PV array is difficult by using conventional techniques due to various reasons like low tracking efficiency, stability issues, etc. This motivates the design of an appropriate control strategy to obtain the maximum power point tracking (MPPT) to harvest MP from the PV array. This paper proposes a combined higher order sliding mode observer (HOSMO)–super-twisting control (STC) for a grid-connected scenario. A perturb and observe (P &O) technique is employed to generate reference voltage, and a HOSMO is proposed to drive the STC by estimating the inductor current of the PV boost converter. The proposed controller performance is evaluated based on response time across various scenarios, including generation changes, dynamic faults, islanding and resynchronization, and load variations in comparison to other existing controllers. These microgrid test cases have been thoroughly simulated, and their effectiveness has been validated in real-time using OPAL-RT (OP4510). [ABSTRACT FROM AUTHOR]

In estimating the parameters of the five unknown parameters Single‐Diode Model (SDM) of the solar photovoltaic (PV) model, a non‐linear equation for the PV cell current is typically utilized. Then, the error between the estimated current and measured current is computed using the objective function called Root‐Mean‐Square‐Error (RMSE). In order to compute the PV cell current in SDM, an iterative method built on the Lambert‐W function is presented in this study. Along with the Lamber‐W function, an optimization algorithm called Weighted Velocity‐Guided Grey Wolf Optimizer (WVGGWO) is used to identify the unknown lumped parameters of SDM of the cell and the module. The proposed WVGGWO is an updated version of the original Grey Wolf Optimizer (GWO). The position update of the GWO has been modified, and the weightage has been provided for the wolf hierarchy. Additionally, by emphasizing the lengthening of each leading wolf's steps towards the others in the earlier search while emphasizing the shortening of the steps while reaching the later iterations, WVGGWO improves both the exploration and exploitation of the original GWO. Four case studies are considered for testing the validity of the proposed algorithm along with the Lambert‐W function. The performance of the proposed approach is compared with seven other well‐known algorithms. The results demonstrate that the suggested approach produces better outcomes than many optimization algorithms. [ABSTRACT FROM AUTHOR]

In any organization, the capability, knowledge and skills play a significant role in success of an employee. For instant, in hospital management, the performance evaluation of an employee is mainly based on qualitative in nature. Evaluation of certain factors such as uncertainty, vagueness and imprecision is based on the decision making ability of the evaluator. The performance evaluation for promotion, incentives, bonuses, growth and development of any employee should be recognized in effective and efficiency manner with appropriate ratings. Therefore, this paper aims to design and implement a multi criteria performance evaluation for hospital employees to get promotion, incentives, bonus, growth and development. In this paper, we propose an Interval Valued Fuzzy Weighted Distance Algorithm (IVFWDA) for performance evaluation. The expected interval and the actual interval of the work achievement, management skill, personal quality, care, safety and risk management features are extracted by Interval Valued Fuzzy Soft Matrix (IVFSM) and it is effectively done using the proposed algorithm. An example is presented as a case study to illustrate the proposed algorithm. Implementation of the proposed algorithm in Maple is also discussed with sample computations. [ABSTRACT FROM AUTHOR]

Objective: Voluntary counseling and testing (VCT) is an integral component of HIV prevention and care strategies worldwide. VCT is considered as an effective strategy in risk reduction among sexually active youth. There is a high burden of HIV in Ethiopia despite a considerable scale up of comprehensive HIV interventions. Hence, the aim of this study was to assess the level of knowledge, attitude and practice of VCT uptake towards HIV among youth of rural part of Tepi town, Ethiopia., Method: A cross sectional study was carried out from May to August 2020. Total numbers of 127 youths in the age group of 15-24 years were recruited in a self-administered questionnaire with 100% response rate. Descriptive analysis was referred to describe the data. Binary logistic regression analysis was used to measure the effect of different variables by computing odds ratio. Multivariable analyses were utilized to determine the relative effect of explanatory variables., Results: The study showed that out of 127 total youth respondents, 111 (87.4%) of the respondents have good knowledge and 99 (78%) had a positive attitude towards VCT. Whereas, 86 (67.7%) of the respondents are aware of practicing VCT on HIV in the past., Conclusions: The findings revel that gender and father's educational status were among the socio-demographic variables that showed statistically significant association with one or more variables affecting youths' knowledge towards VCT uptake. As such, perceived risk of HIV infection, educational level, gender and marital status were statistically responsible for VCT uptake., Competing Interests: All authors declare that they don’t have any conflict of interest., (© 2022 The Authors.)