• Journal of the Korean Geographical Society
• /
• v.37 no.4
• /
• pp.317-336
• /
• 2002

Dongrae-bu, the administrative central area in Busan in Chosun-dynasty(1392-1910), performed the large parts of diplomatic and trading functions with Japan because of its geographical conditions. Because of his location, landscape of Dongrae city-wall is the mirror of political and military meaning in Chosun-dynasty period. Elements of landscape, such as site of city-wall, location and morphology of gates, government official buildings and the road systems can be interpreted by the functional and socio-cultural terms. The changes of landscape during Japanese colonial period(1910-1945) show that destruction of city-walt went on for the purpose of imperialism. Especially, the landscape which had political meaning in Chosun-dynasty had erased in terms of modem urban planning. Cates of city-wall, official guest house, fortress which symbolize the governing and political power of Chosun-dynasty were destructed almost perfectively. New road system was imported Urban planning was effective instrument through which city-wall could be destroyed for the Japanese colonialism. Under those processes, traditional structure was changed towards the dependency on Japan. Those relict landscape are remained in present urban landscape such as road system, cul-de sac, house and cornerstones. Those results of this study show that city-wall in Korea should be studied in terms of socio-cultural aspects in each periods.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.4
• /
• pp.34-40
• /
• 2004

In this paper, we have studied the OCT(Optical Coherence Tomography) system which has been advantages of high resolution, 2-D cross-sectional images, low cost and small size configuration. The characteristics of light source determine the resolution and coherence length. The light source has a commercial SLD with a central wavelength of 1,285 ill11, 35.3 nm(FWHM). The optical delay line is necessary to make equal with the optical path length to scattered light or reflected light from a sample. In order to make equal the optical path length, the stage that is attached to a reference mirror is controled by a step motor. And the interferometer is configured with the Michelson interferometer by using a single mode fiber, and the scanner can be focused on the sample by using a reference ann Also, the 2-dimension cross-sectional images were measured with scanning the transverse direction of the sample by using a step motor. After detecting the internal signal of lateral direction, a scanner is moved to obtain the cross-sectional image of 2-dimension by using step motor. A photodiode, which has high detection sensitivity and excellent noise characteristics has been used. The detected small signal has a noise and interference. After filtering and amplifying the signal, the output signal is demodulated the waveform And then, a cross-sectional image is seen through converting this signal into a digitalized signal by using an AID converter. The resolution of the sample is about 30${\mu}{\textrm}{m}$, which corresponds to the theoretical resolution. Also, the cross-sectional images of onion cells were measured in real time scheme.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.5
• /
• pp.725-731
• /
• 2002

This experiment was performed to understand the changes in plasma leptin in association with plasma IGF-1, body weight and ADG from early growing to late finishing stages of Holstein steers. Blood collection was performed by arterial vein puncture at selected monthly ages of 1 (54 kg), 2.6 (103 kg), 7.2 (205 kg), 13.5 (314 kg), 16.9 (414 kg), 22.2 (550 kg), 24.9 (626 kg) and 27.4 months (695 kg). The blood was analyzed for leptin using the multi-species leptin RIA with recombinant bovine leptin (rbleptin) as standard, plasma IGF-1 was also measured using RIA. Against the standard rbleptin, the multi-species Leptin RIA system's sensitivity, cross reactivity, slope and recovery of 41.0 ng/ml rbleptin in plasma were 4.9 ng/ml, 11.22%, -1.396 and 97.8%, respectively. Plasma leptin measured were more than 5.0 ng/ml, which enable multi-species RIA system to investigate plasma leptin in normal growing steers. Body weight resulted to a highly significant second-degree polynomial relationship with plasma leptin (q=0.54, p<0.0001) and plasma IGF-1 (q=0.44, p<0.0001) from 1 to 27.4 monthly ages. However, the second-degree polynomial curve of plasma leptin and IGF-1 differs showing a concave and convex curvilinear relationship, respectively. ADG was not significantly associated to plasma leptin (r=0.06, p>0.05) and plasma IGF=1 (r=0.06, p>0.05) from 1 to 27.4 monthly ages. Low coefficient, but significant associated increase of plasma leptin and IGF-1 (r=0.12, p<0.008) from 1 to 27.4 months was observed. The uncoordinated increases of plasma IGF-1 at growing and plasma leptin at fattening period, may indicate (1) indirect involvement of endogenous IGF-1 on leptin secretion, and (2) IGF-1 level may signify lean and bone accretion while plasma leptin may mirror body fatness across the monthly ages of Holstein steers.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.1
• /
• pp.1-6
• /
• 2014

In this study, we propose optimized RBFNNs based on night vision face recognition simulator with the aid of $(2D)^2$ PCA algorithm. It is difficult to obtain the night image for performing face recognition due to low brightness in case of image acquired through CCD camera at night. For this reason, a night vision camera is used to get images at night. Ada-Boost algorithm is also used for the detection of face images on both face and non-face image area. And the minimization of distortion phenomenon of the images is carried out by using the histogram equalization. These high-dimensional images are reduced to low-dimensional images by using $(2D)^2$ PCA algorithm. Face recognition is performed through polynomial-based RBFNNs classifier, and the essential design parameters of the classifiers are optimized by means of Differential Evolution(DE). The performance evaluation of the optimized RBFNNs based on $(2D)^2$ PCA is carried out with the aid of night vision face recognition system and IC&CI Lab data.

• Proceedings of the KSMRM Conference
• /
• 2002.11a
• /
• pp.133-133
• /
• 2002

Purpose： The purpose of paper is to implement software to visualize brain fiber tract using a 24-bit color coding scheme and to test its feasibility. Materials and Methods： MR imaging was performed on GE 1.5 T Signa scanner. For diffusion tensor image, we used a single shot spin-echo EPI sequence with 7 non-colinear pulsed-field gradient directions： (x, y, z)：(1,1,0),(-1,1,0),(1,0,1),(-1,0,1),(0,1,1),(0,1,-1) and without diffusion gradient. B-factor was 500 sec/$\textrm{mm}^2$. Acquisition parameters are as follows： TUTE=10000ms/99ms, FOV=240mm, matrix=128${\times}$128, slice thickness/gap=6mm/0mm, total slice number=30. Subjects consisted of 10 normal young volunteers (age：21∼26 yrs, 5 men, 5 women). All DTI images were smoothed with Gaussian kernel with the FWHM of 2 pixels. Color coding schemes for visualization of directional information was as follows. HSV(Hue, Saturation, Value) color system is appropriate for assigning RGB(Red, Green, and Blue) value for every different directions because of its volumetric directional expression. Each of HSV are assigned due to (r,$\theta$,${\Phi}$) in spherical coordinate. HSV calculated by this way can be transformed into RGB color system by general HSV to RGB conversion formula. Symmetry schemes： It is natural to code the antipodal direction to be same color(antipodal symmetry). So even with no symmetry scheme, the antipodal symmetry must be included. With no symmetry scheme, we can assign every different colors for every different orientation.(H =${\Phi}$, S=2$\theta$/$\pi$, V=λw, where λw is anisotropy). But that may assign very discontinuous color even between adjacent yokels. On the other hand, Full symmetry or absolute value scheme includes symmetry for 180$^{\circ}$ rotation about xy-plane of color coordinate (rotational symmetry) and for both hemisphere (mirror symmetry). In absolute value scheme, each of RGB value can be expressed as follows. R=λw｜Vx｜, G=λw｜Vy｜, B=λw｜Vz｜, where (Vx, Vy, Vz) is eigenvector corresponding to the largest eigenvalue of diffusion tensor. With applying full symmetry or absolute value scheme, we can get more continuous color coding at the expense of coding same color for symmetric direction. For better visualization of fiber tract directions, Gamma and brightness correction had done. All of these implementations were done on the IDL 5.4 platform.

• Korean Journal of Optics and Photonics
• /
• v.33 no.2
• /
• pp.74-83
• /
• 2022

The entire process, from the raw material to the final system qualification test, has been developed to fabricate a large-diameter, lightweight reflective-telescope system for a satellite observation. The telescope with 3 anastigmatic mirrors has an aperture of 700 mm and a total mass of 66 kg. We baked a silicon carbide substrate body from a carbon preform using a reaction sintering method, and tested the structural and chemical properties, surface conditions, and crystal structure of the body. We developed the polishing and coating methods considering the mechanical and chemical properties of the silicon carbide (SiC) body, and we utilized a chemical-vapor-deposition method to deposit a dense SiC thin film more than 170 ㎛ thick on the mirror's surface, to preserve a highly reflective surface with excellent optical performance. After we made the SiC mirrors, we measured the wave-front error for various optical fields by assembling and aligning three mirrors and support structures. We conducted major space-environment tests for the components and final assembly by temperature-cycling tests and vibration-shock tests, in accordance with the qualifications for the space and launch environment. We confirmed that the final telescope achieves all of the target performance criteria.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2003.09a
• /
• pp.67-67
• /
• 2003

It is crucial to minimize setup errors of a cancer treatment machine using a high energy and to perform precise radiation therapy. Usually, port film has been used for verifying errors. The Korea Cancer Center Hospital (KCCH) has manufactured digital electronic portal imaging device (EPID) system to verify treatment machine errors as a Quality Assurance (Q.A) tool. This EPID was consisted of a metal/fluorescent screen, 45$^{\circ}$ mirror, a camera and an image grabber and could display the portal image with near real time KIRAMS has also made the acrylic phantom that has lead line of 1mm width for ligh/radiation field congruence verification and reference points phantom for using as an isocenter on portal image. We acquired portal images of 10$\times$10cm field size with this phantom by EPID and portal film rotating treatment head by 0.3$^{\circ}$, 0.6$^{\circ}$ and 0.9$^{\circ}$. To check field size, we acquired portal images with 18$\times$18cm, 19$\times$19cm and 20$\times$20cm field size with collimator angle 0$^{\circ}$ and 0.5$^{\circ}$ individually. We have performed Flatness comparison by displaying the line intensity from EPID and film images. The 0.6$^{\circ}$ shift of collimator angle was easily observed by edge detection of irradiated field size on EPID image. To the extent of one pixel (0.76mm) difference could be detected. We also have measured field size by finding optimal threshold value, finding isocenter, finding field edge and gauging distance between isocenter and edge. This EPID system could be used as a Q.A tool for checking field size, light/radiation congruence and flatness with a developed video based EPID.

• Tuberculosis and Respiratory Diseases
• /
• v.65 no.4
• /
• pp.269-276
• /
• 2008

Background: Although the prevalence of tuberculosis infections (PTBI) is one of the basic epidemiologic indices, no survey has been carried out since 1995 because the nation-wide tuberculosis prevalence survey was changed to a surveillance system. Subjects without a BCG scar are examined in a tuberculin survey. However, it is very difficult to select these subjects under high vaccination coverage. It is important to evaluate the impact of BCG vaccinations on the tuberculin response and estimate the PTBI regardless of the BCG vaccination status. Methods: A nation-wide, school-based cross-sectional tuberculin survey was carried out among first graders in elementary school in 2006. A total of 5,148 children in 40 schools were selected by quota sampling. Tuberculin testing with 0.1 ml of two tuberculin units of PPD RT23 was carried out on 4,018 children. The maximum transverse diameter of induration was measured 48 to 72 hours later. The presence of a BCG scar was checked separately. Results: There were no BCG scars in 6.3% of the subjects. The mean induration size of tuberculin testing was $3.7{\pm}4.4mm$, which included 1,882 (46.8%) subjects with an induration size of 0 mm. The PTBI was 10.9% (439 subjects) using a cut-off point of ${\geq}10mm$ (conventional method). The annual risk of tuberculosis infections (ARTI) was 1.9% when the mean age of the subjects was assumed to be 6 years. There was no difference in the PTBI according to the presence or absence of a BCG scar [11.2% vs 7.6% (OR: 1.54, 95% CI: 0.98~2.43)]. Using a mirror image technique with 16 mm as the cut-off point, the PTBI and ARTI had decreased to 2.4% and 0.4% respectively. Conclusion: PTBI and ARTI, as estimated by conventional methods, appear to be high among BCG vaccinated children. A mirror image technique is more suitable for estimating the indices in a country with an intermediate burden of tuberculosis than the conventional method.

• Progress in Medical Physics
• /
• v.3 no.2
• /
• pp.1-12
• /
• 1992

For intraoperative radiation therapy using electron beams, a cone system to deliver a large dose to the tumor during surgical operation and to save the surrounding normal tissue should be developed and dosimetry for the cone system is necessary to find proper X-ray collimator setting as well as to get useful data for clinical use. We developed a docking type of a cone system consisting of two parts made of aluminum: holder and cone. The cones which range from 4cm to 9cm with 1cm step at 100cm SSD of photon beam are 28cm long circular tubular cylinders. The system has two 26cm long holders: one for the cones larger than or equal to 7cm diamter and another for the smaller ones than 7cm. On the side of the holder is an aperture for insertion of a lamp and mirror to observe treatment field. Depth dose curve. dose profile and output factor at dept of dose maximum. and dose distribution in water for each cone size were measured with a p-type silicone detector controlled by a linear scanner for several extra opening of X-ray collimators. For a combination of electron energy and cone size, the opening of the X-ray collimator was caused to the surface dose, depths of dose maximum and 80%, dose profile and output factor. The variation of the output factor was the most remarkable. The output factors of 9MeV electron, as an example, range from 0.637 to 1.549. The opening of X-ray collimators would cause the quantity of scattered electrons coming to the IORT cone system. which in turn would change the dose distribution as well as the output factor. Dosimetry for an IORT cone system is inevitable to minimize uncertainty in the clinical use.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.8
• /
• pp.253-263
• /
• 2013

Frequency Scanning Interferometry(FSI) system, one of the most promising optical surface measurement techniques, generally results in superior optical performance comparing with other 3-dimensional measuring methods as its hardware structure is fixed in operation and only the light frequency is scanned in a specific spectral band without vertical scanning of the target surface or the objective lens. FSI system collects a set of images of interference fringe by changing the frequency of light source. After that, it transforms intensity data of acquired image into frequency information, and calculates the height profile of target objects with the help of frequency analysis based on Fast Fourier Transform(FFT). However, it still suffers from optical noise on target surfaces and relatively long processing time due to the number of images acquired in frequency scanning phase. 1) a Polarization-based Frequency Scanning Interferometry(PFSI) is proposed for optical noise robustness. It consists of tunable laser for light source, ${\lambda}/4$ plate in front of reference mirror, ${\lambda}/4$ plate in front of target object, polarizing beam splitter, polarizer in front of image sensor, polarizer in front of the fiber coupled light source, ${\lambda}/2$ plate between PBS and polarizer of the light source. Using the proposed system, we can solve the problem of fringe image with low contrast by using polarization technique. Also, we can control light distribution of object beam and reference beam. 2) the signal processing acceleration method is proposed for PFSI, based on parallel processing architecture, which consists of parallel processing hardware and software such as Graphic Processing Unit(GPU) and Compute Unified Device Architecture(CUDA). As a result, the processing time reaches into tact time level of real-time processing. Finally, the proposed system is evaluated in terms of accuracy and processing speed through a series of experiment and the obtained results show the effectiveness of the proposed system and method.