• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.719-726
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• 2004

In this paper, compensation characteristics of distorted WDM channel due to both chromatic dispersion and self phase modulation (SPM) is numerically investigated under the assumptions of non-uniformly distributed fiber dispersion, in order to inspect the application of mid-span spectral inversion (MSSI) to any exact transmission links. The MSSI is compensation method used in this approach. This method has an optical phase conjugator (OPC) placed in mid-way of total transmission length to compensate distorted WDM channels. It is confirmed that MSSI will become applicable to long-haul WDM systems by controlling input light power of transmission channels, when the averaged dispersion of both fiber sections with respect OPC was varied and distributed unequally each other. Applying MSSI to long-haul WDM system, it is possible to remove all in-line compensator, consequently it will be expected to reducing system cost.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.95-97
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• 2004

본 연구에서는 Scanning Capacitance Microscopy (SCM)와 Electrostatic Force Microscopy (EFM)을 이용하여 국소영역에서 실리콘나노 크리스탈의 전기적 특성을 분석하였다. 실리콘 나노 크리스탈은 에어로솔 방식으로 P-type 실리콘웨이퍼 위에 $10{\sim}40\;nm$의 크기와 약 $10^{11}/cm^2$의 밀도를 갖도록 제작하였다. 실리콘 나노 크리스탈에서 전자와 정공의 trapping 현상은 EFM, SCM 이미지를 통하여 관찰하였고 이러한 나노 크리스탈의 국소영역 특성을 MOS 캐패시터 구조의 C-V 특성을 비교 분석하였다. 또한, 나노 크리스탈에 trapping된 전하의 detrapping 과정을 스트레스 조건에 따라 분석하였다.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.753-758
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• 2012

This paper deals with the analysis of vibration and noise sources in a modular-type SPM fractional-slot motor. To reduce cogging torque, torque ripple and unequal radial force, which are the main causes of the electromagnetic vibration, the optimal shape of notch and magnet are designed.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.11-14
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• 2004

This paper presents an implementation of compact vector control system for induction motor using a digital signal processor (DSP) and a smart power module (SPM). The DSP TMS320F2812 has most necessary functions for ac motor control in a single chip and SPM provides a compact power stage. The indirect vector control algorithm is implemented in the drive system using these devices. The developed system is applied by 0.8kW induction servo motor and the all functions are verified through the experiments.

• Environmental Analysis Health and Toxicology
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• v.25 no.1
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• pp.79-84
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• 2010

이 연구의 목적은 유산균(LAB)의 항스트레스 효과를 알아보기 위함이다. 본 실험에서는 ICR 마우스에게 구속 스트레스를 가하면서 혼합유산균과 홍삼추출물을 경구투여 하였다. 5일간 Normal 그룹을 제외한 saline (control), LAB100, LAB200, RGE200에게 구속 스트레스를 주었다. 구속 스트레스를 가한 후에 ICR 마우스에게 kg당 100 mg ($3.0\times10^{11}$ CFU/g) 또는 200 mg $3.0\times10^{11}$ CFU/g)의 혼합유산균(Lactobacillus acidophilus, Pediococcus pentosaseus, Bifidobacterium longum SPM1205)을 투여하였으며 대조물질로는 홍삼 추출물(Red ginseng extract) 200 mg (홍삼추출물)/kg (마우스)을 투여하였다. 마지막 실험일에는 locomotor와 elevated plus-maze 실험을 통하여 마우스의 행동변화를 측정하였다. 그 결과, 혼합유산균을 투여한 그룹에서는 스트레스를 일부 억제하는 효과를 보였다. 특히 Elevated plus-maze 실험에서, 스트레스를 받은 마우스는 open zone에서보다 closed zone에서 더욱 많은 시간을 보냈다. 그렇지만 혼합유산균을 투여한 그룹에서는 open zone에서 더욱 오래 시간을 보냈으며 그 시간은 saline과 RGE200 그룹에 비해서도 길었다. 그것은 또한 아무것도 처리하지 않은 Normal 그룹과도 비슷한 결과이다. 그리고 마우스의 분변에서 유산균수를 측정하였는데 스트레스를 가하고 혼합유산균은 투여하지 않은 saline 그룹에서는 유산균수가 감소했지만 혼합유산균을 투여한 LAB100, LAB200 그룹에서는 유산균수가 증가하였다.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.778-789
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• 2017

This paper presents an improved subdomain method to predict the magnet field distributions and electromagnetic performance of the surface-mounted permanent magnet (SPM) machines with static or dynamic eccentricity. Conventional subdomain models are either based on the scalar magnet potential to predict the rotor eccentricity effect or dependent on the magnetic vector potential without considering the eccentric rotor. In this paper, both the magnetic vector potential and the perturbation theory are introduced in order to accurately calculate the effect of rotor eccentricity on the open-circuit and armature reaction performance. The calculation results are presented and validated by the corresponding finite-element method (FEM) results.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.44-51
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• 2008

The performance design and analysis of an electric motor for vehicles is very complicated due to the variety of parameters. This paper presents the design of the BLDC motor for electric air compressor in high voltage(42V) system and compares with the characteristics of IPM, SPM type BLDC motor. Futher, optimal design for the electric motor has been carried out using Equivalent Magnetic Circuit and FEM Modelling. By analyzing the design results, it is found that design parameters for BLDC motor provided an useful tool for vehicles motor design.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1027-1028
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• 2007

In this paper, the variation of air-gap field intensity caused by the slot-opening in interior permanent magnet (IPM) motor is investigated, which is for predicting the instantaneous magnetic field more preciously in analytical method further. It is different with the approach of dealing the slot-opening effect on the air-gap field distribution with the "relative permeance" function in surface permanent magnet (SPM) motor. The prediction of the air-gap field in IPM motor is much more complex than SPM motor. In this study, an approximate estimation method is adopted based on analyzing the changing of flux path in both the IPM rotor part and stator part, and in additional an analytical function defined as "relative pole-arc" is built. The finite element method(FEM) is used for confirming the slot-opening effect on the field prediction.

• Journal of the Korean Magnetic Resonance Society
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• v.6 no.1
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• pp.45-53
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• 2002

Objectives: This study investigated alterations in regional cerebral blood flow (rCBF) in patients with transient global amnesia (TGA) using statistical parametric mapping 99 (SPM99). Methods: Noninvasive rCBF measurements using 99mTc-ethyl cysteinate dimer (ECD) SPECT were performed on 8 patients with TGA who have ongoing symptoms and 17 age matched controls. The relative rCBF maps in patients with TGA and controls were compared. Results: In patients with TGA, significant decreased rCBF was found along the L superior temporal extending to L parietal region of the brain and L thalamus. There were areas of increased rCBF in the R temporal, R frontal region and R thalamus. Conclusion: We could demonstrate decreased perfusion in left cerebral hemisphere and increased perfusion in right cerebral hemisphere in patients with TGA using SPM99. The imbalanced change of rCBF between bilateral cerebral hemisphere in patients with TGA might suggest that imbalanced neuronal activity between the bilateral hemispheres may have strong relationship to the pathogenesis of the TGA. For quantitative SPECT analysis in TGA patients, we recommend SPM99 rather than the ROI method because of its definitive advantages.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.52-62
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• 2010

The aim of this study was to evaluated the efficacy of mixture of Lactic Acid Bacteria (LAB) and bifidobacteria supplement, which are contained with Lactobacillus acidophilus, Bifidobacterium longum SPM1205, and Pediococcus pentosaceus for the management of constipation in animal model and clinical trials. 5 ICR mice and 4 female constipation subjects were orally taken mixture of LAB and bifidobacteria for 2 weeks. We investigated the number of fecal LAB and harmful enzymes activities before and after mixture of LAB and bifidobacteria application. As a result, fecal LAB count was increased and harmful enzymes activities of intestinal microflora were generally decreased after mixture of LAB and bifidobacteria application. Also, 61 female subjects were randomly assigned to receive either mixture of LAB and bifidobacteria or lactose and were taken three times a day for 2 weeks. Then, we analyzed mixture of LAB and bifidobacteria effect through the questionnaires. Daily consumption of this mixture of LAB and bifidobacteria improved the constipation in constipation group (56.3%) compared with lactose application group (26.7%). Furthermore, after mixture of LAB and bifidobacteria treatment, frequency of hard stool decreased from 0.22 to 0.03. These results indicated that mixture of LAB and bifidobacteria application is effective to improve the constipation.