A sensorless VECTOR CONTROL strategy for induction machine (IM) operating in variable speed systems is presented. The sensorless CONTROL is based on a reduced-order linear observer based on terminal voltage and current as input signals. An estimation algorithm based on this observer is proposed to compute speed. It is shown that the proposed sensorless CONTROL is more sensitive to the stator resistance than to the rotor resistance. In order to tune the observer and to compensate for the parameter variations and the uncertainties, a separate estimation of the stator resistance is introduced. The equations to estimate the stator resistance are derived from the machine differential equations. For certain operating regions of the machine, it is verified that the stator resistance can be accurately estimated regardless of wide stator resistance variation. It is shown that design and hardware implementation of this method is simpler than the previous works. The simulation and experimental results demonstrate the good performance of the proposed observer and estimation algorithm and of the overall indirect-field-oriented-CONTROLled system.

Background: Mosquito CONTROL Programs are articulated to CONTROL Mosquito Borne Diseases and success of such programs depends on the activities of field workers, and their adherence to the standard operating procedures (SOP’s) is governed by their knowledge, attitudes, and practices (KAP). Present study was intended to assess the KAP of mosquito CONTROL workers of Pakistan to get an exact depiction of prevailing situation.   Methods: A cross-sectional descriptive study was conducted in March-April 2020. Questionnaire containing 30 closed and open-ended questions were administrated to participants. Knowledge and practices were evaluated using a scoring system i. e., by giving 1 point to each correct answer while attitude questions were analyzed individually and expressed in percentage for each response. Results: Total 639 workers were interviewed, mean age was 29. 8 (SD ±7. 87) years, majority (65. 1%) was in age group of 18–30 years. Mean knowledge score was 6. 96±1. 28 (range 0–9) with 77. 36% correct answers (P= 0. 073). Mean prac­tices score was 7. 00±1. 62 (range 2–9) with 77. 83% appropriate answers (P< 0. 001). Both knowledge and practices scores were higher for permanent employees, practices score increased with increase in job experience. Very weak posi­tive correlation (r= 0. 127) was observed between knowledge and practice scores. Conclusion: Appropriate practice correlates with better knowledge and positive attitude towards CONTROL activities. Hence, training on protection and protective measures for having a positive attitude among healthcare workers is neces­sary against the fight with mosquitoes.