Double soft-computing techniques based triple functionalities for shunt active power filter with voltage source inverter topology

Firstly, a unified adaptive linear neurons based fundamental component extraction algorithm for dual roles is developed; to generate and synchronize a reference current with respect to the phase and the frequency of supply voltage. A modified method of extracting the final amplitude of the reference current is introduced for improving the quality of the reference current. Second, a hybrid Fuzzy-Proportional (P) controller plus Crisp-Integral (I) controller is designed for a self-charging DC-link voltage control algorithm. The proposed controller is utilized in minimizing the error of DC-link voltage and, its control signal is employed in calculating a reference charging current. The Fuzzy-P controller exhibits simple structure for low computational burden and memory requirement. While, the Crisp-I controller is used to eliminate the steady-state error of DC-link voltage. Performances of the SAPF with the proposed techniques are validated by simulation and experimental works

Integration of dual intelligent algorithms in shunt active power filter

This paper presents an integration of dual intelligent algorithms: artificial neural network (ANN) based fundamental component extraction algorithm and fuzzy logic based DC-link voltage self-charging algorithm (fuzzy self-charging algorithm), in a three-phase three-wire shunt active power filter (SAPF). The ANN and fuzzy logic are trained using the modified Widrow-Hoff (W-H) weight updating algorithm and fuzzy rules respectively. The controller has utilized both algorithms for producing its reference signals and consequently mitigating distorted source currents, improving system power factor (PF) and regulating the DC-link voltage. A 10kHz pulse-width modulation (PWM) switching algorithm is employed to generate the switching signals and therefore the distorted source currents are reshaped to be sinusoidal source current with low total harmonic distortion (THD) value and in phase with source voltages. The effectiveness of the proposed dual intelligent algorithms is verified using Matlab/Simulink

Significant insights into the operation of DC-link voltage control of a shunt active power filter using different control algorithms: a comparative study

A comparative study between a conventional DC-link voltage control algorithm (CDVCA) and a self-charging DC-link voltage control algorithm (SDVCA) is presented. It focuses on the principle operation of both algorithms and their impacts on the performance of a shunt active power filter (SAPF) operation. All analyses are based on the step response of DC-link voltages under different start-up times of the SAPF and different initial DC-link voltage values. Other considered parameters are the ripple factor (RP) of DC-link voltages, estimated and measured DC-link charging currents, and total harmonic distortion (THD) value of supply currents. Thus, this study provides new insights into the operation of DC-link voltage control using different control algorithms. According to the simulation results, the SAPF using the SDVCA has shown better performance than using the CDVCA. By using the SDVCA, the charging process of a DC-link capacitor starts almost instantaneously. Additionally, the overshoot, settling time, and RF of DC-link voltages are reduced. Other than that, THD values of supply currents are improved, by generating low ripple of estimated DC-link charging currents. Experimental validation of the SAPF using the SDVCA is also presented

Single phase shunt active power filter with simplified ADALINE neural network

Shunt active power filter is known as powerful tool to compensate current harmonics. Previous development of its controller was by using modified ADALINE algorithm for harmonics extraction, which somehow still having complex features. Therefore, this paper presents three major improvements to the algorithm in related to sine and cosine vectors, weight updating algorithm, and average square error. The proposed algorithm is designed and developed in shunt APF's controller, and the shunt APF is simulated in MATLAB/Simulink. The simulation results show significant improvement as compared to the previous algorithm

Prevalence of Methicillin-Resistant Staphylococcus aureus at a Tertiary Teaching Hospital in Malaysia

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes severe morbidity, mortality and high medical expenses in many hospitals worldwide. The present study aimed to determine the prevalence of MRSA nosocomial infection, its associated factors, and its antimicrobial susceptibility pattern. This was a retrospective analysis of a database of Multidrug-Resistant Organism (MDRO) that was cultured from patients admitted to Hospital Canselor Tuanku Mukhriz (HCTM) over a period of 2 years (2018-2019). MRSA accounted for 23.6% of total MDRO isolates. The male gender had a higher risk for MRSA acquisition (p<0.05), while the most prevalent setting for MRSA was the orthopaedic ward (47.5%) followed by the medical ward (29.4%). The MRSA strains were significantly isolated from respiratory specimens (55.6%) followed by tissue (50.8%) and blood (27.8%). All MRSA isolates were resistant to penicillin G, oxacillin followed by ciprofloxacin (83.8%) erythromycin (71.5%) and clindamycin (53.5%). MRSA isolates were most susceptible to teicoplanin (99.7%), mupirocin (99.3%), co-trimoxazole (98.4%), rifampicin (97.8%), doxycycline (97.4%), linezolid (95.8%), gentamicin (93.9%) and fusidic acid (86.2%). The trend for MRSA’s antibiotic susceptibility in HCTM for the past 2 years (2018 to 2019) remains unchanged. Further research will be required to investigate the predictor of MRSA by clearly differentiating between MRSA infections and colonisations, hospital-acquired MRSA and community-acquired MRSA

Scienceploration 2023

The Scienceploration Camp is an initiative of the Centre for Pre-University Studies, UNIMAS (PPPU), which aims to increase the interest in science among secondary school students. It is also an effort taken by PPPU towards the achievement of Sustainable Development Goals 4 in providing equal quality education and promoting lifelong learning opportunities for all. On top of that, this camp supports Sarawak’s Digital Economy Strategy in nurturing an integrated ecosystem to foster inclusive digital society, by building the right foundations to grow our local digital economy

ヒカリ ブンカイセイ ラセン ポリシラン オ アシバ ザイリョウ ト スル コウガク カッセイ ポリフルオレン ノ ハッセイ ニ カンスル ケンキュウ

博第1392号甲第1392号博士(工学)奈良先端科学技術大学院大

Aggregation-induced scaffolding: photoscissable helical polysilane generates circularly polarized luminescent polyfluorene

An enantiopair of rigid rod-like helical polysilanes (PSi-S and PSi-R) as a photoscissible scaffold enabled the production of circularly polarised luminescence (CPL)- and circular dichroism (CD)-active di-n-octylpolyfluorene (PF8) aggregates associated with complete removal by PSi-selective photoscissoring at 313 nm. PF8 revealed a considerably high dissymmetry factor (gCPL) of (2–5) × 10−3 at 435 nm due to the chiral β-phase of PF8 after the 313 nm irradiation