• Journal of Industrial Technology
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• v.28 no.A
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• pp.163-166
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• 2008

In this paper, the swept source optical coherence tomography system has realized using a free-space interferometer based on a beam splitter. Personal computer has completed the control for tunable wavelength laser digitally and the B-scan motor as well. From each experiment for an onion and a salmon egg, we confirmed that the in vivo epidermal cross-sectional images for them can be obtained appropriately.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.239-244
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• 2008

We have realized the swept source optical coherence tomography(SS-OCT) by using the self-fabricated wavelength swept laser(wavelength tuning range : 80nm, line-width : 0.12nm, wavelength sweeping rate : 50Hz). In addition, we have used the dual balanced detector that could make a mirror image in OCT display suppressed. We can also fabricate the comb filter of Michelson interferometer type for fast-signal processing in OCT. Using this SS-OCT system for measuring an mirror, a 1mm-depth glass and an onion, we confirmed that the in vivo epidermal cross-sectional images for them can be obtained appropriately.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.1-6
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• 2007

Two impedance imaging systems of multi-frequency electrical impedance tomography (MFEIT) and magnetic resonance electrical impedance tomography (MREIT) are described. MFEIT utilizes boundary measurements of current-voltage data at multiple frequencies to reconstruct cross-sectional images of a complex conductivity distribution (${\sigma}+i{\omega}{\varepsilon}$) inside the human body. The inverse problem in MFEIT is ill-posed due to the nonlinearity and low sensitivity between the boundary measurement and the complex conductivity. In MFEIT, we therefore focus on time- and frequency-difference imaging with a low spatial resolution and high temporal resolution. Multi-frequency time- and frequency-difference images in the frequency range of 10 Hz to 500 kHz are presented. In MREIT, we use an MRI scanner to measure an internal distribution of induced magnetic flux density subject to an injection current. This internal information enables us to reconstruct cross-sectional images of an internal conductivity distribution with a high spatial resolution. Conductivity image of a postmortem canine brain is presented and it shows a clear contrast between gray and white matters. Clinical applications for imaging the brain, breast, thorax, abdomen, and others are briefly discussed.

• Journal of Integrative Natural Science
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• v.7 no.1
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• pp.1-4
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• 2014

Distributed Bragg reflector porous silicon of different characteristics were formed to determine their optical constants in the visible wavelength range using a periodic square wave current between low and high current densities. The surface and cross-sectional SEM images of distributed Bragg reflector porous silicon were obtained using a cold field emission scanning electron microscope. The surface image of distributed Bragg reflector porous silicon indicates that the distributions of pores are even. The cross-sectional image illustrates that the multilayer of distributed Bragg reflector porous silicon exhibits a depth of few microns and applying of square current density during the etching process results two distinct refractive indices in the contrast. Distributed Bragg reflector porous silicon exhibited a porosity depth profile that related directly to the current-time profile used in etch. Its free-standing film was obtained by applying an electro-polishing current.

• Journal of Yeungnam Medical Science
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• v.40 no.4
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• pp.394-401
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• 2023

Background: Pregnancy is associated with a number of physical, emotional, and biological changes that can exacerbate maternal psychological disturbances, such as body image concerns and depression. Sleep disturbances during pregnancy can also have adverse impacts. This study aimed to determine the prevalence of depression, sleep disturbances, and body image concerns among pregnant women. The study also examined the relationship between these factors and pregnancy-related variables, such as bad obstetric history and whether the pregnancies were unplanned. Methods: A cross-sectional study of 146 pregnant patients was conducted at a tertiary care center over 15 months. The patients were administered the Beck Depression Inventory, Pittsburgh Sleep Quality Index, and Body Image Concern Inventory questionnaires. Contingency tables, Fisher exact test, and Spearman correlation were used to identify underlying relationships. Results: The prevalence of depression was 22.6%. Although body image disturbance was noted in only 2.7% of patients, 46.6% had poor sleep quality. Poor sleep was associated with primigravida status. Bad obstetric history and unplanned pregnancy were associated with depression. Depression was found to be significantly correlated with body image disturbances and poor sleep quality. Conclusion: Psychiatric disorders were prevalent during pregnancy. This study highlights the importance of screening for depression in pregnant patients. Counselling and caregiver education can be useful for mitigating psychological disturbances. Management of pregnancies by multidisciplinary teams that include psychiatrists could be immensely useful in improving the pregnancy experiences of patients.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.7-15
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• 2003

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.6
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• pp.596-605
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• 2007

The behavior of a non-buoyant turbulent round jet discharging horizontally was investigated experimentally. The instantaneous velocity field of the jet was obtained using the particle image velocimetry (PIV) method and used to calculate the mean velocity field by phase-averaging. This study tested regular waves with a relatively small wave height for a wavy environmental flow. The centerline and cross-sectional velocity profiles were reported to demonstrate the effect of the waves on the jet diffusion in respect of wave height and wave phase. The wave phase effect was studied for three phases: zero-upcrossing point, zero-downcrossing point, trough. From the results, it is found that the centerline velocity decreases and width of the cross-sectional profile increases as the wave height increases. In addition, the self-similarity of the cross-sectional profile appears to break down although the width of each case along the axial distance does not vary significantly. The phase effect is found to be relatively small compared to the wave height effect.

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

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.93-100
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• 2001

The three dimensional(3D) reconstruction from two dimensional(2D) image data is using in many fields such as RPD(Rapid Product Development) and reverse engineering. In this paper, the main step of 3D reconstruction is comprised of two steps : image processing step and B-spline surface approximation step. In the image processing step, feature points of each cross-section are obtained by means of several image processing technologies. In the B-spline surface approximation step, using the data of feature points obtained in the image processing step, the control points of B-spline surface are obtained, which are used for IGES file of 3D CAD model.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.820-823
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• 1996

In contrast to parts of relatively simple shapes, it is important to match their cross-sectional shapes during mating parts of complicated shapes. It requires the 2.pi. information along their matching boundary to figure out their relative geometrical shapes. In this paper, we propose a method measuring a misalignment at the interface during mating parts with the complicated shapes by using the omnidirectional image sensing system(OLSSA). Also we carried out experiments in order to prove the method, and the results show the feasibility.