• 전기의세계
• /
• v.31 no.5
• /
• pp.355-360
• /
• 1982

In numerical computation, it is desirable to access any row or column, the main diagonal, subarrays, of a matrix without any conflict for successful parallel processing. To meet this requirement special storage scheme is used for conflict-free access of necessary data. Interconnection network, which connects processing elements and processing element memory modules, is required to execute the necessary operations. In this paper we discuss the skewing method for conflict-free, access to various bit slices and single-stage interconnection networks.

• Journal of the Korean Wood Science and Technology
• /
• v.35 no.5
• /
• pp.16-23
• /
• 2007

This study was performed as part of a research project aimed at developing an ultrasonic computed tomography (CT) system of wood for field application. In this reports, we investigate the variation of wave velocities on the cross section of real size wooden structural member to confirm the reason of image distortion on CT image of wood, and then proposed a new image reconstruction method by considering the velocity variation on wood cross section. First of all, the effect of wood anisotropy on ultrasonic velocities of wooden members was investigated. Based on the relationship between ultrasonic velocity and annual ring angle, which was obtained from test results of small clear specimens, ultrasonic velocities of each measuring angle were predicted. Next, they were compared with the ultrasonic velocities measured on five wood disks. There were very large differences between predicted and measured results, thought to be caused by the skewing effect of ultrasound and the presence of juvenile-wood. Based on these findings, a new method was proposed to reconstruct cross-sectional image of wood. By using this method, some distortions on reconstructed images could be removed, and defects were more easily and clearly detected. The minimum size of detectable defect was decreased remarkably, from 33 mm to 13 mm. However, the size of the detected defect was enlarged and the position somewhat shifted to the specimen surface on the CT images, which was also thought to be caused by the skewing effect of ultrasound. Additional research has been planned to solve these problems.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.17 no.4
• /
• pp.227-236
• /
• 1997

Quantitative analysis and imaging of elastic wave propagation are very important for the materials evaluation as well as flaw detection. The elastic wave propagation in an anisotropic media is more complex, and analysis and imaging become essential for flaw detection and materials evaluation. In the anisotropic media, the wave velocity is dependent on the propagation direction. In addition, the direction of group velocity is different from that of phase velocity, the direction of energy flow is not same as the propagation direction of wavefront (beam skewing effect). Especially, this effect becomes critical for the large anisotropic media such as fiber composite materials, and the results using elastic waves for those materials have to be analyzed considering the wave propagation mechanism. Since the analytical approach for the wave propagation in the anisotropic materials is limited, the numerical analysis such as finite difference method (FDM) have been used for these case. Therefore, 2-dimensional FDM program for the elastic wave propagation is developed, and wave propagation in anisotropic media are simulated.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.21 no.3
• /
• pp.20-35
• /
• 2008

Objective : This study was designed to investigate the effects of Curcuma longa Rhizoma(CLR) on asthma. Methods : Detecting splenocyte proliferation rates, cytokines and antigen specific antibody isotypes in bronchoalveolar lavage fluid (BALF). In addition, the present author I also investigated changes in spleen and histopathological changes of lung tissues. Results : Oral administration of CLR lowered spleen weight and splenocyte proliferation rates. In addition, levels of IL-4, IL-17A and Granulocyte/Macrophage Colony-Stimulating Factor(GM-CSF), Th2 driven cytokines, were lowered respectively and IFN-g, and Th1 driven cytokine, were elevated by CLR. Levels of Ovalbumin(OVA) specific IgE and IgGl in BALF were also lowered by oral administration of CLR too. Conclusion : CLR is useful to treat patients with asthma and the mechanisms are related to the in suppression of Th2 skewing reactions.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1210-1211
• /
• 2011

The inherent drawback of iron-core type permanent magnet linear synchronous motor (PMLSM) is detent force that is dependent on several major factors such as PM length, slot clearance, and skewing. To minimize the detent force, this paper proposes a structure optimization using the combination computation of two dimensional (2-D) finite element analysis (FEA) and response surface methodology (RSM). The RSM, that is a collection of the statistical and mathematical techniques, is utilized to predict the global optimal solution based on the FEA calculated results of the detect forces for different combinations of factors. With the help of the combination computation the high capacity iron-core type PMLSM with more than 12000 N propulsion forces only contains less than 3 N detent forces.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.1 no.2
• /
• pp.10-17
• /
• 2012

This paper presents an improved iron loss model, for the computation of the no load iron loss in the stator core of the in-wheel permanent magnet synchronous motors (PMSM), for the cases of with and without stator skew. 2-D analytical model is used for the computation of tooth and yoke flux densities of the in-wheel PMSM. The no load iron loss computed by the improved iron loss model, for the cases of with and without skew is compared with the finite element method (FEM) and the results show good consistency.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.9
• /
• pp.437-442
• /
• 2006

Cogging torque, the primary ripple component in the torque generated by permanent magnet (PM) motors, is due to the slotting on the stator or rotor. This article shows the reduction of cogging torque in a novel axial flux permanent magnet (AFPM) motor through the various design schemes. 3D finite element method is used for the exact magnetic field analysis. The effects of slot shapes and skewing of slot on the cogging torque and the average torque have been investigated in detail.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.04a
• /
• pp.234-238
• /
• 2001

A lot of researches have been done in teleoperation field. For accurate and reliable teleoperation, force reflection is required so that the master can feel the same force, which is measured at reflection have been applied to most of the master device. Therefore the master can not control the force exerted by the slave robot to the environment. But some tasks such as an insertion with very small tolerance, skewing bolt and so forth, require the force command from the master.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.7 no.4
• /
• pp.215-220
• /
• 2007

Leakage current of CMOS circuits has become a major factor in VLSI design these days. Although many circuit-level techniques have been developed, most of them require significant amount of designers' effort and are not aligned well with traditional VLSI design process. In this paper, we focus on technology mapping, which is one of the steps of logic synthesis when gates are selected from a particular library to implement a circuit. We take a radical approach to push the limit of technology mapping in its capability of suppressing leakage current: we use a probabilistic leakage (together with delay) as a cost function that drives the mapping; we consider pin reordering as one of options in the mapping; we increase the library size by employing gates with larger gate length; we employ a new flipflop that is specifically designed for low-leakage through selective increase of gate length. When all techniques are applied to several benchmark circuits, leakage saving of 46% on average is achieved with 45-nm predictive model, compared to the conventional technology mapping.

• New & Renewable Energy
• /
• v.6 no.4
• /
• pp.41-49
• /
• 2010

Over the last decade, wind turbine industry has rapidly increased around world. These days many parts of the wind generators are induction generator. But it has some problems such as gearbox failure, rotor excitation and maintenance. Thus many manufacturers are considered permanent magnet synchronous generator named PMSG and direct drive. PMSG uses NdFeB magnet has many the advantage compare with induction generator. In this study, 3MW class outer rotor type PMSG for wind turbine is proposed. The generator features 2.6m stator outer radius, 1200mm stator length, 81 pole pairs, 14 rated rpm, 42kN/$m^2$ shear force density and 94.2% efficiency. Design and analysis generator using FEM program. Then calculate and derivate no load voltage, losses, conductor temperature. To reduce total harmonic distortion and cogging torque, the stator is applied the stator skewing. And to evaluate the designed generator, compare with other generators by active mass per rating torque and torque density.