• Journal of Yeungnam Medical Science
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• 제37권2호
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• pp.90-97
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• 2020

Background: To minimize damage to the ovarian reserve, it is necessary to evaluate the follicular density in the ovarian tissue surrounding endometriosis on preoperative imaging. The purpose of the present study was to evaluate the usefulness of subtraction pelvic magnetic resonance imaging (MRI) to detect ovarian reserve. Methods: A subtracted T1-weighted image (^subT1WI) was obtained by subtracting unenhanced T1WI from contrast-enhanced T1WI (^ceT1WI) with similar parameters in 22 patients with ovarian endometriosis. The signal-to-noise ratio (SNR) in ovarian endometriosis, which was classified into the high signal intensity and iso-to-low signal intensity groups on the T2-weighted image, was compared to that in normal ovarian tissue. To evaluate the effect of contrast enhancement, a standardization map was obtained by dividing ^subT1WI by ^ceT1WI. Results: On visual assessment of 22 patients with ovarian endometriosis, 16 patients showed a high signal intensity, and 6 patients showed an iso-to-low signal intensity on T1WI. Although SNR in endometriosis with a high signal intensity was higher than that with an iso-to-low signal intensity, there was no difference in SNR after the subtraction (13.72±77.55 vs. 63.03±43.90, p=0.126). The area of the affected ovary was smaller than that of the normal ovary (121.10±22.48 vs. 380.51±75.87 ㎟, p=0.002), but the mean number of pixels in the viable remaining tissue of the affected ovary was similar to that of the normal ovary (0.53±0.09 vs. 0.47±0.09, p=0.682). Conclusion: The subtraction technique used with pelvic MRI could reveal the extent of endometrial invasion of the normal ovarian tissue and viable remnant ovarian tissue.

• 대한의생명과학회지
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• 제10권2호
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• pp.115-120
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• 2004

To investigate the correlation between the magnetic resonance imaging (MRI) of cerebral fat embolism that is induced by injecting oleic acid into 10 cats, and a pathologic diagnosis. Using a microcatheter, 30 ${mu}ell$ of oleic acid was injected into the internal carotid artery of 10 cats. MR T2-weighted image (T2WI), diffusion-weighted image (DWI) and Gadolinium-enhanced T1-weighted image (Gd-enhanced T1WI) were obtained after 30 minutes and 2 hours of embolization. After 30 minutes of the embolization, lesions of very high signal intensity were detected by T2WI in 6 cats, and of slightly high signal intensity in 2 cats; in the remaining 2 cats, signal intensity was normal. DWI showed lesions of very high intensity in 9 cats and of slightly high intensity in one cat. According to the findings of light microscopic examination, infarcted lesions mainly involved the gray matter, but also some white matter. A magnetic resonance imaging diagnosis for cerebral fat embolism that was induced by oleic acid through the internal carotid artery in cats showed high signal intensity on the T2WI and the DWI within an initial 2 hours, and with a well enhancement on the Gd-enhanced T1WI. Considering cellular edema, cerebrovascular injury and extracellular space widening, we assumed pathologically that cytotoxic and vasogenic edema exists at the same time.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.415-418
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• 1996

Etching Process, one of the most important process in semiconductor fabrication, has input control part of which components are pressure, gas flow, RF power and etc., and plasma gas which is complex and not exactly understood is used to etch wafer in etching chamber. So this process has not real-time feedback controller based on input-output relation, then it uses EPD(End Point Detection) signal to determine when to start or when to stop etching. Various type EPD controller control etching process using EPD signal obtained from optical intensity of etching chamber. In development EPD controller we concentrate on compensation of this signal intensity and setting the relative signal magnitude at first of etching. We compensate signal intensity using neural network learning method and set the relative signal magnitude using fuzzy inference method. Potential of this method which improves EPD system capability is proved by experiences.

• 한국정밀공학회지
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• 제29권10호
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• pp.1096-1100
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• 2012

In the phase-shift measurement method, the distance light travels can be obtained based on the phase difference between the reference signal and the measured signal. When the object having various colors is measured, the intensity of the measured signal much varies even at the same distance, and it causes different phase delay due to wide dynamic range input to a signal processing circuit. In this work, an measured intensity control method is proposed to solve this phase delay problem.

• 한국식품영양과학회지
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• 제30권1호
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• pp.43-47
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• 2001

Electron spin resonance (ESR) spectroscopy was used to investigate the effect of irradiation dose on the ESR signal intensity and to identify the stability of radicals after 9 weeks of storage in order to detect irradiated shellfishes. The irradiated shellfishes (short-necked clam, purplish washington clam, freshwater clam, jackknifed clam, scallop and hard-shell mussel) presented an asymmetric absorption in shape at $g_{1}$=2.002~2.003 and $g_{2}$=1.998. The strength of the ESR signal increased linearly with the applied doses (1~7 kGy). A highly positive correlation coefficients ($R^{2}$=0.9136~0.9896) were obtained between the irradiation dose and corresponding ESR signal intensity. The intensity of the signals after irradiation was stable even after 9 weeks of storage at 5$\pm$1$^{\circ}C$.

• 한국콘텐츠학회논문지
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• 제17권12호
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• pp.266-271
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• 2017

본 연구는 자기공명검사 시 재현성이 달라져 신호강도가 저하되는 문제점을 후처리 기법인 DOTS 기법을 적용함으로써 개선하고자 하였다. 연구방법은 재현성이 떨어져 신호강도 저하가 가장 빈번하게 발생하는 간 검사를 시행한 30명을 대상으로 하였으며, 조영제 주입 전 후 영상을 획득한 다음 DOTS 기법으로 영상을 후처리하여 적용 여부에 따른 영상의 신호강도를 비교 평가하였다. 연구결과 영상의 신호강도는 DOTS 기법을 적용한 경우가 적용하지 않은 경우보다 조영제 주입 전에는 183.3%(적용 전 $1038.0{\pm}70.7$, 적용 후 $2940.7{\pm}179.6$), 주입 후에는 1118.4%($444.1{\pm}92.4$, 적용 후 $5410.5{\pm}168.4$) 유의하게 증가하였다. 이는 후처리 기법인 DOTS 기법을 통해 영상척도의 기준을 재설정하여 개선한 것으로써 자기공명검사 시 재현성이 달라져 신호강도가 저하되는 문제를 근본적으로 해결하였다는 데 의의가 있다.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.5124-5130
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• 2014

조영제의 희석률 변화에 따른 신호강도를 분석하여 조영증강 자기공명혈관조영검사 시 점도와 삼투압에 따른 부작용을 최소화하고 신호강도를 높여 영상의 질을 향상시키고자 하였다. 연구방법은 조영제가 혈관에 주입되면 혈액과 희석되어 mol 농도가 변화되고, 그에 따라 신호강도의 변화를 일으킴에 착안하여 phantom을 제작하였다. phantom 결과를 바탕으로 임상실험은 2013년 11월부터 2014년 1월까지 조영제를 희석한 군(30명)과 희석하지 않은 군(30명)으로 구분하여 뇌혈관의 신호강도를 비교하였다. 연구결과, 조영제 mol 농도 변화에 따른 phantom의 신호강도는 0.0125mmol부터 급격히 증가하다 20mmol에서 최고점을 이룬 후 200mmol부터 평형을 이루었다. 임상실험에서도 조영제를 희석하여 검사한 영상의 신호강도가 모두 높게 나타나, 1000mmol 조영제 사용에 비해 500mmol로 희석하여 사용함이 최고점인 20mmol에 근접하여 우수함을 알 수 있었다. 결론적으로 조영제를 희석하여 사용함으로써 점도와 삼투압을 저하시키고, 영상의 질을 향상시킬 수 있었으므로 임상적용의 유용성이 높다고 할 수 있다.

• 한국정보전자통신기술학회논문지
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• 제3권4호
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• pp.70-75
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• 2010

이 논문은 광케이블인 optical fiber를 통해 의료용 signal을 전송 할 때 porarization obtain fiber 에서 mono mode fiber로 교체되는 지점에 integrated optic인 wave conductor를 사용하여, optical signal intensity의 maximum를 sensing 하기 위한 Algorithm Brent을 설계하고 이를 검토하였다.

• Journal of Korean Neurosurgical Society
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• 제57권2호
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• pp.94-99
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• 2015

Objective : The purpose of our study was to assess prevalence of carotid intraplaque hemorrhage (IPH) and associations between territorial acute infarction and IPH on magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) in patients with acute neurologic symptoms. Methods : 83 patients with suspected acute neurologic symptoms were evaluated with both brain diffusion weighted imaging (DWI) and carotid MPRAGE sequences. Carotid plaque with high signal intensity on MPRAGE of >200% that of adjacent muscle was categorized as IPH. We analyzed the prevalence of IPH and its correlation with territorial acute infarction. Results : Of 166 arteries, 39 had a carotid artery plaque. Of these arteries, 26 had carotid artery stenosis less than 50%. In all carotid arteries, MR-depicted IPH was found in 7.2% (12/166). High-signal intensity on DWI was found in 17.5% (29/166). Combined lesion with ipsilateral high-signal intensity on DWI and IPH on carotid MPRAGE sequence was found in 6 lesions (6/166, 3.6%). Of patients with carotid artery plaque, MR-predicted IPH was found in 30.8% (12/39) and match lesions with high-signal intensity on DWI and MPRAGE was found in 15.4% (6/39). MR-predicted IPH was significantly higher prevalence in high-grade stenosis group (p=0.010). Relative risk between carotid MPRAGE-positive signal and ipsilateral high-signal intensity on DWI in arteries with carotid artery plaques was 6.8 (p=0.010). Conclusion : Carotid MPRAGE-positive signal in patients was associated with an increased risk of territorial acute infarction as detected objectively by brain DWI. The relative risk of stroke was increased in high-grade stenosis categories.

• 말소리와 음성과학
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• 제9권2호
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• pp.119-124
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• 2017

This study investigates how perception of easy sentences varies with prosody pattern, sound intensity, and signal-to-noise ratio(SNR) in young adults with normal hearing who were in their 20's. The results showed that the presence of proper prosody pattern in the sentences increased correct perception rate of the target sentences, and that the lower the intensity and SNR, the lower the sentence perception scores. The results also showed that SNR had a greater effect on the sentence perception scores than sound intensity. There was a significant decrease of perception scores starting at the level of 15 dB and +3 SNR for the sentences with prosody pattern, while starting at the level of 18 dB and +6 SNR for the sentences without prosody pattern, ending up with a very poor perception score as sound intensity and SNR gets lower. There was a significant difference in the perception score of the sentences with prosody pattern between 20 year-old group and 21 year or older group in several listening conditions of sound intensity and SNR.