• Journal of international Conference on Electrical Machines and Systems
• /
• v.2 no.4
• /
• pp.390-393
• /
• 2013

In this paper, we proposed how the V-skew applied of the rotor to inprove the characteristics of cogging torque in large PMSM. Large PMSM is difficult to apply a pitch of the diagonal magnetic skew because of the motor's structure and making. In addition, the force in the direction of z-axis occurs when the diagonal skew is applied. So we are applying the optimal v-skew to reduce torque ripple and cogging torque because this reduces the noise and vivration on the motor. Throug FEM dD analysis, we studied to find the optimal v-skew angle for reducing torque ripple.

• Bulletin of the Korean Mathematical Society
• /
• v.55 no.6
• /
• pp.1627-1638
• /
• 2018

In this paper, we study an special type of cyclic codes called skew cyclic codes over the ring ${\mathbb{F}}_p+v{\mathbb{F}}_p+v^2{\mathbb{F}}_p$, where p is a prime number. This set of codes are the result of module (or ring) structure of the skew polynomial ring (${\mathbb{F}}_p+v{\mathbb{F}}_p+v^2{\mathbb{F}}_p$)[$x;{\theta}$] where $v^3=1$ and ${\theta}$ is an ${\mathbb{F}}_p$-automorphism such that ${\theta}(v)=v^2$. We show that when n is even, these codes are either principal or generated by two elements. The generator and parity check matrix are proposed. Some examples of linear codes with optimum Hamming distance are also provided.

• Journal of applied mathematics & informatics
• /
• v.31 no.3_4
• /
• pp.337-342
• /
• 2013

In this paper, we study a special class of linear codes, called skew cyclic codes, over the ring $R=F_p+vF_p$, where $p$ is a prime number and $v^2=v$. We investigate the structural properties of skew polynomial ring $R[x,{\theta}]$ and the set $R[x,{\theta}]/(x^n-1)$. Our results show that these codes are equivalent to either cyclic codes or quasi-cyclic codes. Based on this fact, we give the enumeration of distinct skew cyclic codes over R.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.3
• /
• pp.390-397
• /
• 2008

Permanent Magnet Linear Synchronous Motor (PMLSM) has high efficiency, high energy density, and high control-ability. But, the detent force always is produced by the structure of slot-teeth. There are the disadvantages such as noise and vibration of the apparatuses are induced and the control ability is curtailed because detent force acts as thrust ripple. Therefore, the detent force reduction is an essential requirement in PMLSM. Generally, the method, skewing permanent magnet or slot-teeth, is used to reduce the detent force. But the thrust is decreased at the same time. If permanent magnet is skewed, the lateral force which operates as the perpendicular direction of skew direction is generated in linear guide of PMLSM. So, V-skew model is proposed for the reduction of lateral force. The lateral force acts as braking force in linear motion guide, and it has bad influence to the characteristics of PMLSM. However, these problems will not be solved by 2-dimensional Finite Element Analysis (FEA). So, in this paper 3-dimensional FEA is applied to analyze the PMLSM where permanent magnet is skewed and has overhang. The detent force and thrust characteristics considering skew and overhang effects of permanent magnet are analyzed by 3-dimensional FEA and the results are compared with experimental values to verify the propriety of analysis.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1021-1022
• /
• 2007

By enforcing skew of permanent magnet, detent force decreases, but lateral force that acts for vertical direction of moving direction occurs. This force deteriorates various performance of PMLSM as that acts to friction force between mover and LM guide. Therefore, in this paper, V skew model is proposed for lateral force's reduction and simulation results are compared to experimental value.

• Proceedings of the KIEE Conference
• /
• 2006.10d
• /
• pp.80-82
• /
• 2006

본 논문에서는 영구자석의 스큐형상에 따른 영구자석형 선형 동기기(PMLSM: Permanent Magnet Linear Synchronous Motor)의 제반 특성을 해석하였다. 단방향 Skew의 경우 스큐 방향과 직각 방향으로 작용하는 Lateral Force가 존재한다. 이러한 Lateral Force는 가동자와 LM 가이드 사이에 마찰력으로 작용하여 PMLSM의 제반 특성을 저하시킨다. Lateral Force의 저감을 위하여 영구자석을 V형상으로 모델링하여 단방향 착자 시의 특성과 비교하였다. V-skew 모델의 lateral force가 단방항 skew 모델의 lateral force의 11.3[%]로 감소하는 양호한 결과를 얻었다.

• Bulletin of the Korean Mathematical Society
• /
• v.49 no.4
• /
• pp.715-736
• /
• 2012

Brown provided a structure theorem for a class of perfect ideals of grade 3 with type ${\lambda}$ > 0. We introduced a skew-symmetrizable matrix to describe a structure theorem for complete intersections of grade 4 in a Noetherian local ring. We construct a class of perfect ideals I of grade 3 with type 2 defined by a certain skew-symmetrizable matrix. We present the Hilbert function of the standard $k$-algebras R/I, where R is the polynomial ring $R=k[v_0,v_1,{\ldots},v_m]$ over a field $k$ with indeterminates $v_i$ and deg $v_i=1$.

• East Asian mathematical journal
• /
• v.19 no.1
• /
• pp.63-71
• /
• 2003

In his invited lecture presented during the First Conference of the Mathematical Society of the Republic of Moldova($Chi\c{s}in\v{a}u$, August 2001) W. A. Dudek posed several open problems on the role and properties of the skew element in the theory of n-ary groups. In this note we give the partial solutions of some of these problems.

• Proceedings of the KIEE Conference
• /
• 2007.04c
• /
• pp.134-137
• /
• 2007

By enforcing skew of permanent magnet, detent force decreases, but lateral force that acts for vertical direction of moving direction occurs. This force deteriorates various performance of PMLSM as that acts to friction force between mover and LM guide. Therefore, in this paper, V skew model is proposed for lateral force's reduction and simulation results are compared to experimental value.

• Structural Engineering and Mechanics
• /
• v.71 no.6
• /
• pp.657-668
• /
• 2019

The numerical thermal frequency responses of the skew sandwich shell panels structure are investigated via a higher-order polynomial shear deformation theory including the thickness stretching effect. A customized MATLAB code is developed using the current mathematical model for the computational purpose. The finite element solution accuracy and consistency have been checked via solving different kinds of numerical benchmark examples taken from the literature. After confirming the standardization of the model, it is further extended to show the effect of different important geometrical parameters such as span-to-thickness ratios, aspect ratios, curvature ratios, core-to-face thickness ratios, skew angles, and support conditions on the frequencies of the sandwich composite flat/curved panel structure under elevated temperature environment.