• Clinical and Experimental Reproductive Medicine
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• v.36 no.2
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• pp.111-119
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• 2009

Objective: The aim of this study was to compare the clinical efficacy of clomiphene citrate (CC) and letrozole combined with gonadotropins for controlled ovarian stimulation (COS) in patients with CC-induced thin endometrium Methods: Fifty-one intrauterine insemination cycles performed in patients who previously had a thin endometrium (<8 mm) to ovulation induction using CC were included in this study. A CC 100 mg/day (CC+gonadotropin group, n=26) or letrozole 2.5 or 5 mg/day (letrozole+gonadotropin group, n=25) was administered on day 3~7 of the menstrual cycle, combined with gonadotropins at dose 75~150 IU every other day starting on day 5~7. We compared total dose of gonadotropin used, endometrial thickness, endometrial pattern, number of follicles ${\geq}14\;mm$ on hCG day, pregnancy rate and multiple pregnancy rate between the two groups, which were statistically analyzed using Mann-Whitney U test or Fisher's exact test, where appropriate. Results: There were no significant differences in clinical characteristics such as age, duration of infertility, number of previous IUI cycles, basal serum hormone levels and cause of infertility between the two groups. In both groups, the endometrium was significantly thicker than that of previous ovulation induction cycles using CC. No significant differences were found in the total dose of gonadotropin used, day of hCG administration, the rate of triple endometrium and pregnancy rate. The number of follicles ${\geq}14\;mm$ was significantly lower ($3.7{\pm}1.7$ vs. $2.8{\pm}1.7$, p=0.03) and the endometrium on hCG day was significantly thicker ($7.7{\pm}1.5$ vs. $9.1{\pm}1.7$, p=0.001) in letrozole+gonadotropin group compared to CC+gonadotropin group. Conclusion: The clomiphene citrate and letrozole combined with gonadotropins appear to avoid the undesirable effects on the endometrium frequently seen with CC for ovulation induction. However, in terms of adequate endometrial development or optimal follicular growth, letrozole may be more beneficial than CC for gonadotropin-combined COS in patients with CC-induced thin endometrium. Further prospective randomized controlled studies in a larger scale will be necessary to confirm our findings.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1994.05a
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• pp.20-33
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• 1994

우리나라에 있어서 양액재배는 지금으로부터 40년전으로 거슬러 올라간다. 그러나 현재의 발전수준은 양액재배가 발전된 나라들에 비하면 특히 그 수준이 저조한 상태에 머물고 있다. 그러나 최근에 들어 그러한 현상은 농민을 에워싼 환경의 변화에 따라 크게 자극을 받고 있다. 시설원예의 일부가 양액재배로 전환되어 가는 일이 전국적으로 확산되어가고 있다. 이러한 현상은 마치 사람이 깊은 잠을 자고 난 후에 다시 활발한 활동을 시작하는 것처럼 지구상의 생물의 주기적인 활동현상과 유사해서 장래의 발전에 기대가 된다. (중략)

• Electrical & Electronic Materials
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• v.1 no.4
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• pp.333-341
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• 1988

포리에틸렌, 테레프탈레트를 금속감화물로 오염시켜 열자극특성을 중심으로 가동이온의 중성화, 재이온화 및 이동의 과정등에서 이온의 거동에 관하여 검토하였다. PET가 오염이 되면 이온이 증가되고 전극금속의 영향이 있으며 고온에서 서브리니어 특성을 가지며 가동이온의 증성화 현상이 있는 것을 밝혔다. 가동이돈의 주기적 운동에 기인한 직류전기전도모델로 실험한 결과가 정성적으로 정상전류 전압 특성과 일치함이 입증되었다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.294-295
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• 2017

태양광발전시스템은 설비 사용률을 최대화하기 위하여 PV 모듈을 최대 전력점에서 운전하는 MPPT(Maximum Power Point Tracking) 제어가 반드시 필요하다. 기존의 MPPT 알고리즘은 경사법에 기반을 두기 때문에 일정한 MPPT 주기마다 일정한 크기의 PWM Duty 비의 자극을 주고, 그에 따른 출력 전력의 변화를 감지하여 최대 전력점을 향한 다음 운전점을 찾는다. 이러한 MPPT 알고리즘을 실제 날씨 환경에 적용할 때 최대전력을 생산하기 위한 최적의 MPPT 주기와 PWM Duty 비의 변량은 다양한 일사량의 프로파일 형태에 따라 달라진다. 그러므로 최적의 MPPT 주기와 PWM Duty 비의 변량을 결정하기 위해서는 실제 날씨 환경에서 다양한 일사량 프로파일의 패턴에 대한 분석이 필수적이다. 본 논문에서는 대한민국 중부지역의 전형적인 맑은 날씨와 흐린 날씨에서 실제 일사량을 측정, 분석하여 MPPT 목표 효율을 최대화할 수 있는 MPPT 주기를 제시하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1697-1698
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• 2013

정보처리 기술이 발전함에 따라 정보에 대한 접근과 소통은 더욱 빠르고 편리하게 되었고, 동시에 사용자의 정보에 대한 요구 또한 세분화되고 다양해지면서, 이러한 다양한 요구에 대응하기 위해서 사용자의 경험과 소통하여 인지과정에 영향을 줄 수 있는 감성이 중요하게 인식되고 있다. 감성은 동일한 외부자극에 대해 개인의 경험, 환경 등에 따라 다르게 나타나기 때문에 객관적으로 측정하기가 어렵지만, 외부자극에 대해 반사적이고 직관적으로 발생하여 의사결정 과정에 지속적으로 영향을 주기 때문에 사용자의 경험과 소통하여 사용자의 요구를 이해할 수 있는 정보를 제공한다. 본 논문에서는 이미지 공유 사이트를 이용하여 이미지라는 외부자극에 대해 사용자들이 느낀 어휘들을 수집하고 긍정과 부정 감성을 분석하여 어휘를 기반으로 이미지의 감성을 측정하고 평가하였다.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.404-408
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• 1999

개에서 정상 발정주기 때와 자궁 축농증에 이환 되었을 경우 이에 대한 전침 자극의 효과를 알아보기 위하여 본 실험을 실시하였다. 정상 자궁 운동은 발정기 때에 최대이었으며 발정정지기 때에 운동성이 감소되거나 결여되었다. 발정정지기 때에 전침자윽을 하거나 Prostagrandin $F_2{\alpha}$를 투여하였을 경우에는 자궁의 운동성이 크게 증가하였다. 자궁경관이 열린 자궁축농증에 이환된 두 마리에서 전침자극을 3~4일간 실시하였다. 자궁의 직경은 감소되었고 질 분비물은 증가한 후 이후 감소하였다. 환축은 회복되는 경향을 보였으나 축주의 요구에 의하여 난소자궁절제술을 시행하였다. 본 실험의 결과를 통하여 전침자극은 자궁 축농증에 이환된 환축에서 축주가 번식용으로 계속 기르기를 원한다거나 또는 난소자궁절제술을 환축에 적용하는데 있어서 수술적인 위험이 높을 때에 적용 가능한 새로운 치료적 대안이 될 수 있음을 알 수 있었다.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.289-296
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• 2009

In this study, I presented power control unit with potential use in the magnetic stimulation of biological systems. The effect of the magnetic stimulation depends on the geometry and orientation of the induced electric field as well as on the current pulse waveform delivered by the stimulator coil. TMS is achieved from the outside of the head using pulses of electromagnetic field that induce an electric field in the brain. There are numerous possibities in the applications TMS, such as diagnosis and therapy through the brain stimulation. These factors are very important to define the equipment requirements and characteristics in that the topology of the power supply and the size and geometry of the coil. The proposed solution is the generation of current pulses with variable amplitude and duration, according to a user defined input. Another solution is the topology that uses elements to store and transfer energy from the power source to the load. In addition to proposed topology, an adequate control strategy and right set of the power circuit parameters made possible to obtain unipolar waves and bipolar waves.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.14-19
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• 2000

Purpose : This study was to present the functional brain mapping of both functional magnetic resonance imaging(MRI) and transcranial magnetic stimulation(TMS) in a case of schizencephaly. Materials and methods : A 28-year-old man, who had left hemiplegia and schizencephaly in right cerebral hemisphere, was exacted with both functional MRI and TMS. Motor function of left hand was decreased whereas right hand was within normal limit. For functional MRI, gradient-echo echo planar imaging($TR/TE/{\alpha}$=1.2 sec/90 msec/90) was employed. The paradigm of motor task consisted of repetitive self-paseo hand flexion-extension exercises with 1-2 Hz periods. An image set of 10 slices was repetitively acquired with 15 seconds alternating periods of task performance and rest and total 6 cycles (three ON periods and three OFF periods) were performed. In brain mapping, TMS was performed with the round magnetic stimulator (mean diameter; 90mm). The magnetic stimulation was done with 80% of maximal output. The latency and amplitude of motor evoked potential(MEP)s were obtained from both abductor pollicis brevis(APB) muscles. Results : Functional MRI revealed activation of the left primary motor cortex with flexion-extension exercises of healthy right hand. On the other hand, the left primary motor cortex, left supplementary motor cortex, and left promoter areas were activated with flexion-extension exercises of left hand. In TMS, magnetic evoked potentials were induced in no areas of right cerebral hemisphere, but in 5 areas of left corebral hemisphere from both abductor pollicis brevis. Latency, amplitude, and contour of response of the magnetic evoked potentials in both hands were similar. Conclusion : Functional MRI and TMS in a patient with schizencephaly were successfully used to localize cortical motor function. Ipsilateral motor pathway is thought to be secondary to reinforcement of the corticospinal tract of the ipsilateral motor cortex.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.237-244
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• 1994

We investigated the qualitive and quantitative properties in EEG signal which responds to auditory stimulus with increaing the sound-cutting frequency from 2 Hz to 20 Hz by 2 Hz step units, by chaotic dynamics. To bigin with, general chaotic properties such as fractal mechanism, 1 If frequency spectrum and positive Lyapunov exponent are discussed in EEG signal. For evoked potential with given auditory stimulus, the route to chaos by bifurcation diagram and the changes in geometrical property of Poincare sections of 2-dimensional psedophase space is observed. For that containing spontaneous potential, seen as the random background signal, the chaotic attractors in 3-dimensional phase space are found containing the same infomation as the above mentioned evoked potential. Finally the chinges of Lyapunov exponent by various sound-cutting frequencies of stimulus and by the various spatial positions (occipital region) in a brain surface to be measured, are illustrated meaningfully.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1665-1671
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• 2012

The purpose of this study was to look into changes in voice using acoustic analysis during the process of neuromuscular electrical stimulation targeting dysphagia treatment. Fifteen man with dysphagia caused by stroke was treated neuromuscular electrical stimulation for two months and intensity of voice, $F_0$, Jitter, Shimmer, NNE were measured. The results of this study that improvement in functions of dysphagia and Jitter, Shimmer were stabilized. But there was not significantly changes of $F_0$. NNE was improved after the intervention, but still showed abnormal levels. This result suggests a possibility of effects that Neuromuscular electrical stimulation has on stabilization of Jitter, Shimmer and intensity of voice.