• 환경생물
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• 제27권1호
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• pp.82-87
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• 2009

우리나라의 주요 우점종인 상수리나무, 굴참나무, 신갈나무의 생태적 특성을 밝히기 위하여 식물생장에서 가장 중요하다고 판단되는 광, 토양수분, 영양소를 이들 3종의 참나무 유식물에 각각 실내에서 처리하여 그 생육반응을 관찰하고, 분석하고자 시도하였다. 상수리나무와 굴참나무는 광이 높을수록 잘 자라는 경향이 있었고, 신갈나무만이 뚜렷한 경향이 없었다. 신갈나무는 낮은 광도에서도 생육이 크게 감소하지 않았다 굴참나무와 신갈나무는 수분구배에 따라 생육의 차이가 없었고, 상수리나무만이 약간 높은 구배에서 잘 자랐을 뿐이었다. 상수리나무, 굴참나무와 신갈나무 모두는 영양소가 적을 때 잘 자랐고, 높을수록 못 자랐다. 영양소 구배에 따른 감소정도는 굴참나무, 신갈나무, 상수리나무 순으로 낮았다. 이상으로 볼 때, 신갈나무는 피음조건에, 상수리나무는 토양이 다습한 조건에 그리고 굴 참나무는 유기물이 적은 조건에서 각각 적응한 종이라고 판단된다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.555-558
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• 1997

A new approach to silent MR imaging using a rotating DC gradient has been explored and experimentally studied. As is known, acoustic or sound noise has been one of the major problems in handling patients, mainly due to the fast gradient pulsings in interaction with the main magnetic field. The sound noise is also proportionally louder as the magnetic field strength becomes larger. In this article, we have described a new imaging technique using a mechanically rotating DC gradient coil as an approach toward silent MR imaging, i.e., a mechanically rotated DC gradient effectively replaces both the phase encoding as well as the readout gradient pulsings and data obtained in this manner provides a set of project ion data which later can be used or the projection reconstructionorwithsomeinterpolation techniques one can also perform conventional 2-D FFT (Fast Fourier Transform) image reconstruction. We found, with this new technique, that the sound noise intensity compared with the conventional imaging technique, such as spin echo sequence, is reduced down to -20.7 dB or about 117.5 times. The experimental pulse sequence and its principle are described and images obtained by the new silent MR imaging technique are reported.

• 대한통합의학회지
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• 제5권2호
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• pp.83-90
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• 2017

Purpose : The purpose of this study was to investigate the correlation between shoulder gradient, range of motion of the neck, and subjective pain level of the potential risk group of smart-phone addiction. Methods : The subjects of this study were 90 women's who had potential risk of smart-phone addiction. VAS was used to measure subjectively pain intensity. Global Postural System was used to measure forward head posture. CROM was used to measure flexion, extension, lateral flexion of cervical range of motion. Results : The results of this study showed that was significant positive correlation between the both shoulder gradient, and cervical range of motion(p<.05). Statistically significant negative correlation between the VAS and left lateral flexion(p<.05). Conclusions : The difference between the gradient of both shoulders increased with the use of smart-phone addiction, and the cervical left lateral flexion decreased as the pain increased. This suggests that recognition on decrease of using smart phone and postural correction is necessary.

• IEIE Transactions on Smart Processing and Computing
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• 제4권5호
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• pp.349-353
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• 2015

The conventional intensity histogram does not indicate edge information, which is important in the perception of image contrast. In this paper, we propose a multi-cue histogram (MCH) to represent a collaborative distribution of both the intensity and the edges of an image. Based on the MCH, if the intensity values have high frequency and a large gradient magnitude, they are spread into a larger dynamic range. Otherwise, the intensity values are not strongly stretched. As a result, image details, such as edges and textures, can be enhanced while artifacts and noise can be prevented, as demonstrated in the experimental results.

• 천문학회지
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• 제29권1호
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• pp.75-81
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• 1996

We mapped the $^{13}CO$ line in the dark nebula L134 using the 14-m Taeduck radio telescope with a 57 arcsec beam and one beam spacing. The cloud has a spherical shape with an intensity peak ridge extended from the northwest to the southeast directions. The halfwidth and the radial velocity of the lines peak at the region of the cloud center. The radial velocity decreases from the cloud center towards the north and south directions. The integrated line intensity distributions in the space-velocity plane show some structure and a velocity gradient. The $^{13}CO$ and $H_2CO$ clouds and dark clouds are closely related in space in shape, outer boundary, and intensity peak positions. The $^{13}CO$ integrated line intensity is linearly proportional to the visual extinction.

• 대한의용생체공학회:의공학회지
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• 제28권1호
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• pp.24-28
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• 2007

Presuming that firing neurons have motions inside the MRI magnet due to the interaction between the neuronal magnetic field and the main magnetic field, we applied motion encoding gradients to dissected snail ganglia to observe faster responding MRI signal than the BOLD signal. To activate the snail ganglia in synchronization with the MRI pulse sequence, we used electrical stimulation with the frequency of 30 Hz and the pulse width of 2s. To observe the fast responding signal, we used the volume selected MRI sequence. The magnetic resonance signal intensity, measured with 8 ms long motion encoding gradient with a 20mT/m gradient strength, decreased about $3.46{\pm}1.48%$ when the ganglia were activated by the electrical stimulation.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1753-1763
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• 2002

Stress and displacement fields for a propagating crack in a functionally gradient material (FGM) which has shear modulus as $\mu$=$\mu$$\_$0/(1＋ζX) are derived. The equations of motion in FGM which is nonhomogeneous material are different from those of homogeneous material. The stress intensity factors in stress fields have influence on odd terms of γ$\^$n/2-1/(n=1,3,5,...,) but stress at crack tip only retains term of γ$\^$-1/2/, where the γ is a radius of cylindrical coordinates centered at crack tip. When the FGM constant ζ is zero or γ→0, the fields for FGM are almost same as the those for isotropic material.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.525-528
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• 1999

Abstract - In this paper, a segmentation method for brain Magnetic Resonance(MR) image using region clustering technique with statistical distribution of gradient image and fuzzy rules is described. The brain MRI consists of gray matter and white matter, cerebrospinal fluid. But due to noise, overlap, vagueness, and various parameters, segmentation of MR image is a very difficult task. We use gradient information rather than intensity directly from the MR images and find appropriate thresholds for region classification using gradient approximation, rayleigh distribution function, region clustering, and merging techniques. And then, we propose the adaptive fuzzy rules in order to extract anatomical structures and diseases from brain MR image data. The experimental results shows that the proposed segmentation algorithm given better performance than traditional segmentation techniques.

• 설비공학논문집
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• 제22권11호
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• pp.773-780
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• 2010

The dispersion of plume which is emitted from a chimney is governed by a lot of factors： wind, local terrain, turbulence intensity of atmosphere, and temperature, etc. In this study, we numerically investigate the plume dispersions for various altitudinal temperature gradients and wind speeds. The normal atmosphere has the temperature decrease of $0.6^{\circ}C/100m$, however, actually the real atmosphere has the various altitudinal temperature profiles according to the meteorological factors. A previous study focused on this atmospheric temperature gradient which induces a large scale vertical flow motion in the atmosphere thus makes a peculiar plume dispersion characteristics. In this paper, the effects of the atmospheric temperature gradient as well as the wind speed are investigated concurrently. The results for the developing processes in the atmosphere and the affluent's concentrations at the ambient and ground level are compared under the various altitudinal temperature gradients and wind speeds.

• Journal of Photoscience
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• 제2권1호
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• pp.31-35
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• 1995

Light signals in the form of intensity gradient, propagation direction, and wavelength elicit diverse mechanical responses ("photomechanical responese") in most organisms. The single cell ciliates, Stentor coeruleus and Blepharisma japonicum, are particularly sensitive to the light of visible wavelengths. In this paper, the way in which the seemingly sophisticated light signal transduction is triggered by the photosensory apparatus will be described in terms of the photoreceptor structure and photochemical function.