Multistage Inverters Control Using Surface Hysteresis Comparators

Menshawi K. Menshawi,Saad Mekhilef 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1

An alternative technique to control multilevel inverters with vector approximations has been presented. The innovative control method utilizes specially designed two-dimensional hysteresis comparators to simplify the implementation and improve the resultant waveform. The multistage inverter designed with maximum number of levels is operated in such a way to approximate the reference voltage vector by exploiting the large number of multilevel inverter vectors. A three-stage inverter with the main high voltage stage made of three phase, six-switch and singly-fed inverter is considered for application to the proposed design. The proposed control concept is to maintain a higher voltage stage state as long as it can lead to a target vector. High and medium voltage stages controllers are based on surface hysteresis comparators to hold the switching state or to perform the necessary change to achieve its reference voltage with minimal switching losses. The low voltage stage controller is designed to approximate the target reference voltage to the nearest inverter vector using the nearest integer rounding and adjustment comparators. Model simulation and prototype test results show that the proposed control technique clearly outperforms the previous control methods.

Multistage Inverters Control Using Surface Hysteresis Comparators

Menshawi, Menshawi K.,Mekhilef, Saad The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.1

An alternative technique to control multilevel inverters with vector approximations has been presented. The innovative control method utilizes specially designed two-dimensional hysteresis comparators to simplify the implementation and improve the resultant waveform. The multistage inverter designed with maximum number of levels is operated in such a way to approximate the reference voltage vector by exploiting the large number of multilevel inverter vectors. A three-stage inverter with the main high voltage stage made of three phase, six-switch and singly-fed inverter is considered for application to the proposed design. The proposed control concept is to maintain a higher voltage stage state as long as it can lead to a target vector. High and medium voltage stages controllers are based on surface hysteresis comparators to hold the switching state or to perform the necessary change to achieve its reference voltage with minimal switching losses. The low voltage stage controller is designed to approximate the target reference voltage to the nearest inverter vector using the nearest integer rounding and adjustment comparators. Model simulation and prototype test results show that the proposed control technique clearly outperforms the previous control methods.

Two-Dimensional Hysteresis Comparators to Control Multistage Inverters with Maximum Number of Levels

M. K. Menshawi,M. K. Menshawi,S. Mekhilef 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

Specially designed two-dimensional hysteresis comparators have been proposed to replace the algebraic calculations to control multistage inverter designed with maximum number of levels. The inverter is operated to approximate the reference voltage vector exploiting the large number of multilevel inverter vectors. Three-stage inverter with singly-fed main stage is considered to apply the proposed design. The controller concept is to maintain the higher voltage stage state as long as this state can lead to the target vector. The high and medium voltage stages controllers are based on twodimensional hysteresis comparators to hold the switching state or to perform the necessary change with minimum switching losses. The low voltage stage controller is designed to approximate the reference voltage to the nearest inverter vector using nearest integer rounding and adjustment comparators. Simulation and experimental results show that the proposed controller outperforms the previous control methods in terms of simplicity, harmonics reductions and robustness.

A Functional Perspective on the Embryology and Anatomy of the Cerebral Blood Supply

Khaled Menshawi,Jay P Mohr,Jose Gutierrez 대한뇌졸중학회 2015 Journal of stroke Vol.17 No.2

The anatomy of the arterial system supplying blood to the brain can influence the development of arterial disease such as aneurysms, dolichoectasia and atherosclerosis. As the arteries supplying blood to the brain develop during embryogenesis, variation in their anatomy may occur and this variation may influence the development of arterial disease. Angiogenesis, which occurs mainly by sprouting of parent arteries, is the first stage at which variations can occur. At day 24 of embryological life, the internal carotid artery is the first artery to form and it provides all the blood required by the primitive brain. As the occipital region, brain stem and cerebellum enlarge; the internal carotid supply becomes insufficient, triggering the development of the posterior circulation. At this stage, the posterior circulation consists of a primitive mesh of arterial networks that originate from projection of penetrators from the distal carotid artery and more proximally from carotid-vertebrobasilar anastomoses. These anastomoses regress when the basilar artery and the vertebral arteries become independent from the internal carotid artery, but their persistence is not uncommon in adults (e.g., persistent trigeminal artery). Other common remnants of embryological development include fenestration or duplication (most commonly of the basilar artery), hypoplasia (typically of the posterior communicating artery) or agenesis (typically of the anterior communicating artery). Learning more about the hemodynamic consequence that these variants may have on the brain territories they supply may help understand better the underlying physiopathology of cerebral arterial remodeling and stroke in patients with these variants.

Leukemia propagating cells in Philadelphia chromosome-positive ALL: a resistant phenotype with an adverse prognosis

Nadia El-Menshawy,Sherin M. Abd-Aziz,Enas M. Elkhamisy,Mohammed A. Ebrahim 대한혈액학회 2018 Blood Research Vol.53 No.2

Background Targeted therapy has revolutionized the management of Philadelphia chromo-some-positive (Ph+) acute lymphoblastic leukemia (ALL); however, relapse still occurs because of the presence of quiescent stem cells, termed leukemia propagating cells (LPCs). This study aimed to assess the phenotypic diversity of LPCs in adult patients with Ph+ B-Acute ALL (B-ALL) and to assess its prognostic impact. Methods Seventy adults with newly diagnosed Ph+ B-ALL were recruited at the Mansoura Oncology Center. Multiparameter flow cytometry studies of mononuclear blast cells for cluster of differentiation (CD)34, CD38, and CD58 were performed. Results Seventeen patients had blasts with the pattern of LPCs (CD34+CD38-CD58-), while 53 cases had other diverse phenotypic patterns. The rate of complete response was significantly lower in patients with the LPC phenotype (47% vs. 81%, P=0.006). The median time to achieve a complete response was prolonged in patients with the CD34+ CD38-CD58- phenotype (48 vs. 32 days, P=0.016). The three-year overall survival was significantly lower in patients with the CD34+CD38-CD58- phenotype (37% vs. 55% respectively, P=0.028). Multivariate analysis showed that the CD34+CD38- CD58- phenotype was an independent risk factor for overall survival. Conclusion The presence of CD34+CD38-CD58- LPCs at diagnosis allows rapid identification of higher risk patients. Risk stratification of these patients is needed to further guide therapy and develop effective LPCs-targeted therapy to improve treatment outcome.

Leukemia propagating cells in Philadelphia chromosome-positive ALL: a resistant phenotype with an adverse prognosis

Nadia El-Menshawy,Sherin M. Abd-Aziz,Enas M. Elkhamisy,Mohammed A. Ebrahim 대한혈액학회 2018 Blood Research Vol.53 No.2

Background Targeted therapy has revolutionized the management of Philadelphia chromo-some-positive (Ph+) acute lymphoblastic leukemia (ALL); however, relapse still occurs because of the presence of quiescent stem cells, termed leukemia propagating cells (LPCs). This study aimed to assess the phenotypic diversity of LPCs in adult patients with Ph+ B-Acute ALL (B-ALL) and to assess its prognostic impact. Methods Seventy adults with newly diagnosed Ph+ B-ALL were recruited at the Mansoura Oncology Center. Multiparameter flow cytometry studies of mononuclear blast cells for cluster of differentiation (CD)34, CD38, and CD58 were performed. Results Seventeen patients had blasts with the pattern of LPCs (CD34+CD38-CD58-), while 53 cases had other diverse phenotypic patterns. The rate of complete response was significantly lower in patients with the LPC phenotype (47% vs. 81%, P=0.006). The median time to achieve a complete response was prolonged in patients with the CD34+ CD38-CD58- phenotype (48 vs. 32 days, P=0.016). The three-year overall survival was significantly lower in patients with the CD34+CD38-CD58- phenotype (37% vs. 55% respectively, P=0.028). Multivariate analysis showed that the CD34+CD38- CD58- phenotype was an independent risk factor for overall survival. Conclusion The presence of CD34+CD38-CD58- LPCs at diagnosis allows rapid identification of higher risk patients. Risk stratification of these patients is needed to further guide therapy and develop effective LPCs-targeted therapy to improve treatment outcome.

A novel new correlation measure for cubic Pythagorean fuzzy sets related to structures of $KU$-ideals on $KU$-algebras

Ola W. Abd El-Baseer,Jeong Gon Lee,Young Bae Jun,Amany M. Menshawy,Kul Hur,Samy M. Mostafa 원광대학교 기초자연과학연구소 2023 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.25 No.1

In this paper, the concepts of cubic Pythagorean $KU$-ideals are introduced and several properties are investigated. Also, relations between cubic Pythagorean $KU$-ideals and cubic Pythagorean ideals are given. The pre-image of cubic Pythagorean $KU$-ideals under homomorphism of $KU$-algebras are defined and how the pre-image of cubic Pythagorean $KU$-ideals under homomorphism of $KU$-algebras become cubic Pythagorean $KU$-ideal are studied. Moreover, the Cartesian product of cubic Pythagorean $KU$-ideals in Cartesian product $KU$-algebras is given. Finally, novel new correlation coefficient between two cubic Pythagorean fuzzy sets are also studied.

$(3,3,\sqrt[3]{\cdot})$-picture fuzzy structures of a $BCC$-ideal of $BCC$-algebras and their correlation coefficient

Samy M. Mostafa,Ola W. Abd El-Baseer,D. L. Shi,Amany M. Menshawy,Kul Hur 원광대학교 기초자연과학연구소 2024 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.27 No.2

A picture fuzzy set is one of the generalizations of Atanassove's (IFSs) fuzzy set. Under this environment, in this manuscript, we familiarize a new type of extensions of fuzzy sets called cubic root fuzzy sets (briefly, $\sqrt[3]{\cdot}$-Fuzzy sets) and Fermatean fuzzy sets to contrast $(3,3,\sqrt[3]{\cdot})$-picture sets. We introduce the notion of $(3,3,\sqrt[3]{\cdot})$-picture fuzzy $BCC$-ideals of $BCC$-algebras. After then, we study the homomorphic image and inverse image of $(3,3,\sqrt[3]{\cdot})$-picture fuzzy $BCC$-ideals under homomorphism of $BCC$-algebras. Moreover, the Cartesian product of $(3,3,\sqrt[3]{\cdot})$-picture fuzzy $BCC$-ideals of $BCC$-algebras is given. Finally, we introduce the concept of correlation for $(3,3,\sqrt[3]{\cdot})$-picture fuzzy sets, which is a new extension of the correlation of Atanassove's IFSs and investigated several properties.