Improved Stability and Damping Characteristics of LCL-Filter Based Distributed Generation System

Faiz Muhammad Talib,Khan Danish,Khan Muhammad Mansoor,Ali Abdar,Tang Houjun 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

The voltage source inverter is a key component in the distributed power generation systems where the LCL -fi lter is a popular choice for interfacing with the grid. However, the well-known resonance issue associated with the LCL -fi lter deteriorates the control performance and risk the inverter system stability. The inverter control design plays a signifi cant role to ensure the quality of the injected grid current and stable operation according to the requirements of grid interconnection standards. This paper deals with an alternative control design method that modifi es the internal damping loop design to improve the stability and damping characteristics. The proposed design employs a compensator across the fi lter and feedbacks the output of the augmented plant at the reference voltage point, and named as parallel feedforward compensation method. The fi lter capacitor current measured for damping loop implementation, and a high-pass fi lter compensator adopted in the proposed confi guration. The proportional capacitor current feedback compensation method is considered for comparative studies. The current loop stability and control performance characteristics are investigated in detail under the resonance frequency and fi lter parameters variation condition. The signifi cant outcomes of the proposed scheme are faster dynamic response, higher delay compensation capability, relatively improved resonance suppression, and potential for better tracking performance. An experimental prototype is developed to validate the effi cacy of the proposed method.

Complex Fuzzy Rough Aggregation Operators and their Applications in EDAS for Multi-Criteria Group Decision-Making

Faiz Muhammad Khan,Naila Bibi,Saleem Abdullah,Azmat Ullah 한국지능시스템학회 2023 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.23 No.3

One of the notable advantages of the complex fuzzy set is its ability to incorporate not only satisfaction and dissatisfaction but also the absence of vague information in two-dimensional scenarios. By combining a fuzzy rough set with a complex fuzzy set, this study aims to provide a powerful and versatile tool for multi-criteria group decision-making (MCGDM) in complex and uncertain situations. This approach, based on EDAS (evaluation based ondistance from average solution) method allows decision-makers to consider multiple criteria, account for uncertainty and vagueness, and make informed choices based on a wider range of factors. The main goal of this study is to introduce complex fuzzy (CF) rough averaging aggregation and geometric aggregation operators and embed these operators in EDAS to obtain remarkable results in MCGDM. Furthermore, we propose the CF rough weighted averaging (CFRWA), CF rough ordered weighted averaging (CFROWA), and CF rough hybrid averaging (CFRHA) aggregation operators. Additionally, we present the concepts of CF rough weighted geometric (CFRWG), CF rough ordered weighted geometric (CFROWG), and CF rough hybrid geometric (CFRHG) aggregation operators. A new score function is defined for the proposed method. The basic and useful aspects of the explored operators were discussed in detail. Next, a stepwise algorithm of the CFR-EDAS method is demonstrated to utilize the proposed approach. Moreover, a real-life numerical problem is presented for the developed model. Finally, a comparison of the explored method with various existing methods is discussed, demonstrating that the exploring model is more effective and advantageous than existing approaches.

Prevalence of PALB2 Germline Mutations in Early-onset and Familial Breast/Ovarian Cancer Patients from Pakistan

Muhammad Usman Rashid,Faiz Ali Khan,Noor Muhammad,Asif Loya,Ute Hamann 대한암학회 2019 Cancer Research and Treatment Vol.51 No.3

Purpose Partner and localizer of BRCA2 (PALB2) is a breast cancer susceptibility gene that plays an important role in DNA repair. This is the first study assessing the prevalence of PALB2 mutations in early-onset and familial breast/ovarian cancer patients from Pakistan. Materials and Methods PALB2 mutation screening was performed in 370 Pakistani patients with early-onset and familial breast/ovarian cancer, who were negative for BRCA1, BRCA2, TP53, CHEK2, and RAD51C mutations, using denaturing high-performance liquid chromatography analysis. Mutations were confirmed by DNA sequencing. Novel PALB2 alterations were analyzed for their potential effect on protein function or splicing using various in silico prediction tools. Three-hundred and seventy-two healthy controls were screened for the presence of the identified (potentially) functional mutations. Results A novel nonsense mutation, p.Y743*, was identified in one familial breast cancer patient (1/127, 0.8%). Besides, four in silico-predicted potentially functional mutations including three missense mutations and one 5' untranslated region mutation were identified: p.D498Y, novel p.G644R, novel p.E744K, and novel c.-134_-133delTCinsGGGT. The mutations p.Y743* and p.D498Y were identified in two familial patients diagnosed with unilateral or synchronous bilateral breast cancer at the ages of 29 and 39, respectively. The other mutations were identified in an early-onset (! 30 years of age) breast cancer patient each. All five mutations were absent in 372 healthy controls suggesting that they are disease associated. Conclusion Our findings show that PALB2 mutations account for a small proportion of early-onset and hereditary breast/ovarian cancer cases in Pakistan.

Is it Necessary to Submit Grossly Normal Looking Gall Bladder Specimens for Histopathological Examination?

Tayeb, Muhammad,Rauf, Fozia,Ahmad, Khurshid,Khan, Faiz Muhammad Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.4

Background: The objectives of the study were to: 1) determine the frequency of incidental malignancy in unsuspected/grossly normal looking gall bladders; 2) determine the frequency of malignancy in suspected/grossly abnormal looking gall bladders. Materials and Methods: This prospective, cross sectional study was carried out at a tertiary care hospital in Pakistan, during a four year period (Jan 2009-dec2012). All the cholecystectomy cases performed for gallstone diseases were examined initially by a surgeon and later on by a pathologist for macroscopic abnormalities and accordingly assigned to one of the three categories i.e. grossly normal, suspicious, abnormal/malignant. Frequency of incidental carcinoma in these categories was observed after receiving the final histopathology report. Results: A total of 426 patients underwent cholecystectomy for cholelithiasis, with a 1:4 male: female ratio. Mean age of the patients was 45 years with a range of 17-80 years. The frequency of incidental gallbladder carcinoma was found to be 0.70 %(n=3). All the cases of gallbladder carcinoma were associated with some macroscopic abnormality. Not a single case of incidental carcinoma gallbladder was diagnosed in 383 'macroscopically normal looking' gallbladders. Conclusions: Incidental finding of gall bladder cancer was not observed in any of macroscopically normal looking gall bladders and all the cases reported as carcinoma gallbladder had some gross abnormality that made them suspicious. We suggest histopathologic examination of only those gall bladders with some gross abnormality.

Molecular Characterization of FLT3 Mutations in Acute Leukemia Patients

Ishfaq, Mariam,Malik, Arif,Faiz, Mariam,Sheikh, Ishfaq Ahmad,Asif, Muhammad,Khan, Muhammad Nasrullah,Qureshi, Muhammad Saeed,Zahid, Sara,Manan, Abdul,Arooj, Mahwish,Qazi, Mahmood Husain,Chaudhary, Ade Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Fms-like tyrosine kinase 3 (FLT3) performs a vital role in the pathogenesis of hematopoietic malignancies. Therefore in recent times, the focus of several studies was on use of FLT3 as a prognostic marker. The present study investigated the molecular characterization and incidence of FLT3 mutations in acute leukemia patients in Pakistan. A total of 55 patients were studied, of which 25 were suffering from acute lymphoblastic leukemia (ALL) and 30 were suffering from acute myeloid leukemia (AML). The polymerase chain reaction demonstrated FLT3/ITD mutations in 1 (4%) of 25 ALL patients, a male with the L2 subtype. In AML cases the rate was 4 (13.3%) of 30, three males and one female. The AML-M4 subtype was found in three and the AML M2 subtype in the other. In the AML cases, a statistically significant (p=0.009) relationship was found between WBC (109/L) and FLT3/ITD positivity. However, no significant relationship was found with other clinical parameters (p>0.05). In acute myeloid leukemia (AML) $FLT3/ITD^+$ mutation was more prevalent in elderly patients 31-40 age groups, 21-30 and 51-60 age groups respectively. In acute lymphoblastic leukemia (ALL) statistically no significant relationship was found between clinical features and FLT3/ITD positivity (p>0.05). However, in acute lymphoblastic leukemia (ALL) $FLT3/ITD^+$ mutation was more commonly found in age groups of 21-30.