• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.239-247
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• 2015

Since 2006, new national forest inventory in Korea has been restructured to assess current status and and monitor the changes in forest resources based on permanent sample plots. The objective of estimate this study is to assess changes in forest resources such as land use/cover categories and forest stand variables. For this study, permanent plot data were collected between 2006-2008 and 2011-2013 in Chungcheongbuk-do, respectively. In order to produce land use/cover change matrix which plays an important role as an activity data for estimating GreenHouse Gas inventory, permanent plots were classified into six land use/cover categories. Additionally, matrixes for assessing the changes in age class and dominant tree species can provide more detailed information. For forest stand variables(tree density, basal area, growing stock, mean diameter at breath height, and mean height), their growth and change were assessed. The periodic annual growth ratios for tree density and basal area were slightly declined whereas that of growing stock was estimated to be about 3.7%. The uncertainty of changes in forest stand variables is less than 5%, except for tree density (RSE: 58%). The variation of tree density is relatively high compared to the other variables.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1141-1149
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• 2009

In Bone Mineral Density(BMD) measurements, accuracy and precision must be superior in order to know the small changes in bone mineral density and actual biological changes. Therefore the purpose of this study is to increase the reliability of bone mineral density inspection through appropriate management of image quality from machines and inspectors. For the machine management method, the recommended phantom from each bone mineral density machine manufacturer was used to take 10~25 measurements to determine the standard amount and permitted limit. On each inspection day, measurements were taken everyday or at least three times per week to verify the whether or not change existed in the amount of actual bone mineral density. Also evaluations following Shewhart control chart and CUSUM control chart rules were made for the bone mineral density figures from the phantoms used for measurements. Various forms of management became necessary for machine installation and movement. For the management methods of inspectors, evaluation of the measurement precision was conducted by testing the reproducibility of the exact same figures without any real biological changes occurring during reinspection. There were two measurement methods followed: patients were either measured twice with 30 measurements or three times with 15 measurements. An important point to make regarding measurements is that after the first inspection and any other inspection following, the patient was required to come off the inspection table completely and then get back on for any further measurements. With a 95% confidence level, the precision error produced from the measurement bone mineral figures produced a precision error of 2.77 times the minimum of the biological bone mineral density change (Least significant change: LSC). In order to assure reliability in inspection, there needs to be good oversight of machine management and measurer for machine operation and inspection error. Accuracy error in machines needs to be reduced to under 1% for scientific development in bone mineral density machines.

• Journal of Acupuncture Research
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• v.18 no.6
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• pp.188-205
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• 2001

Objective : The purpose of this studies was to determine the effect of Carthami semen, Bogol-Tang and Rhynchosia volubilis Lour. on changes of trabecular area and physiological metabolites in the ovariectomized osteoporotic Rats. Methods : In order to induce estrogen deficient osteoporosis, ovariectomy was done on rats. Then the Carthami semen, Bogol-Tang and Rhynchosia volubilis Lour. were orally administerd: Such indexes were measured as the changes of body weight, bone mineral density, trabecular area in tibia, and levels of osteocalcin, bone alkaline phosphatase, calcium, phosphorus, cholesterol, triglyceride, aspartate aminotransferase and alanine aminotransferase in serum. Results : 1. The change of bone mineral density in Bogol-Tang group and Rhynchosia volubilis lour. group. was significantly increased compare to control group. 2. The change of trabecular area % in epiphysis of tibia in Carthami semen group was significantly increased compare to control group. 3. The change of trabecular area % in diaphysis of tibia in Bogol-Tang group was significantly increased compare to control group. 4. The change of serum osteocalcin in Bogol-Tang group was significantly decreased compare to control group. 5. The change of serum bone alkaline phosphatase in Bogol-Tang group was significantly decreased compare to control group. 5. The change of serum bone alkaline phosphatase in Bogol-Tang group was significantly decreased compare to control group. 6. The change of1 serum calcium in Rhynchosia volubilis lour. group was significantly decreased compare to control group. 7. The change of phosphorus in Carthami semen group and Rhynchosia volubilis Lour. group was significantly decreased compare to control group. 8. The change of serum cholesterol and triglyceride of experimental groups were decreased in comparison with control group. 9. The change of serum AST(Aspartate aminotransferase : GOT) in Rhynchosia volubilis Lour. group was decreased compare to control group. 10. The change of serum ALT(Alanine aminotransferase : GPT) in Bogol-Tang group was decreased compare to control group.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.317-326
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• 1991

The purpose of this study was to establish the principle and the clinical application of dynamic tomogram of a human head by using the dental machine. For this study, a block of wax with details lying at three parallel planes and a human dry skull were used. This experiment was reexamined the dynamic tomogram with specialized radiographic device and view box, and the radiograms taken by the change of exposure time according to the numbers of film used in x-ray taking and taken according to the change of kVp and the types of film were analyzed density with the densitometer. From this study, the obtained results were as follows: 1. When the underexposed radiograms taken by angulation of clockwise and counter-clockwise direction of the film and skull. were superimposed and moved laterally, it was possible to focus on right and left jaws and teeth. 2. The superimposition of the two underexposed radiograms according to each condition of x-ray taking showed some differencies in density visually, and the measurement of density with the densitometer was 1.23 to 1.57 in 75kVp and 1.34 to 1.70 in 90kVp. 3. The superimposition of the two underexposed radiograms according to the kinds of x-ray film showed almost equal density visually, and the measurement of density with the densiometer was 1.34 to 1.37. 4. When seven radiograms taken by each condition of x-ray taking were superimposed on the view box, a intense rear light of view box didn't transilluminate film density regardless of the conditions of x-ray taking. Even though seven radiograms taken according to types of film were superimposed on the view box, a more intense rear light of view box was required to transilluminate total density of films. 6. Long film-object distance resulted in the enlargement and blurring of radiographic images.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.237-248
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• 1998

Landcover has been largely influenced by human activities, especially in recent days. The analysis of the change of land use by urbanized development is useful for determining development plan hereafter. This study aimed to the quantitative analysis about the urban sprawl within 12 years from 1985 to 1996, at Chonan, and for extracting the characteristics of change. For this purpose, this study performed land cover classifications using Landsat TM data . A hybrid classification method was used to classify satellite images into seven types of land cover. Road network digitied from 1:25,000 topographic map was rasterized and overlaid on the landcover map. A result of this study showed that area of forest and paddy decreased due to urban sprawl. Especially from 1993 to 1996, the change of land use progressed rapidly because of merging a city and a country in Chonan. The size of patch in forest had been smaller and irregular form. It is a general progress that size of patch in forest had been smaller and irregular form. It is a general progress that the forest have changed the paddy and bare land paddy and bare land have changed low-density urban or high-density urban. This explained how urbanized Chonan was and applied the suggeston of plan in landuse with the result of this study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.115-119
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• 1995

Electrical conduction characteristics of Polyethylene/Ethylene vinyl acetate blends of varing vinyl acetate content(1% and 4%) were investigated at electric fields ranging from 10$\^$6/ to 10.$\^$8/ V/cm over the temperature range of 30 and 85$^{\circ}C$. It was obser-ved that the extent of current density was changed at the blends and the rate of change of current den-sity was slightly suppressed at high field range, but PE and EVA were not shown. The change of con-duction characteristics and a suppression in rate of change of current density were attributed to the VA content in PE.EVA blends.

• Electrical & Electronic Materials
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• v.9 no.2
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• pp.165-173
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• 1996

We prepared polythiophene and poly(3-methylthiophene) films, known as conducting polymer, by electrochemical method. Polythiophene and poly(3-methylthiophene) films were doped and undoped dopant for the studing the understanding of doping mechanism and possible application to the color change switch. We observed that the anodic, cathodic wave and absorption spectra were slightly changed during doping and undoping process in polythiophene. It shows that doping and undoping process were showed some difference by the appearance and disappearance of polaron and bi-polaron. In the relation of the peak of oxidative current density and potential sweep rate of cyclic voltammograms, the amount of dopant in polythiophene film was homogeneously increased at low scan rate. This also can be applied to the poly(3-methlythiophene).

• Journal of the Korean Wood Science and Technology
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• v.40 no.2
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• pp.101-109
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• 2012

Wood composites are a hygroscopic material and have ability to exchange its moisture content with air. This study investigated the formaldehyde emission and moisture content change of four wood composites (particleboard (PB), medium density fiberboard (MDF), high density fiberboard (HDF), laminated HDF (L-HDF)) as a function of bake-out temperature and time. The composites were baked out for 1, 3, 5, 7, 10, 14, 21, and 28 days at temperatures of $20{\pm}2$, $35{\pm}2$, and $50{\pm}2^{\circ}C$ in a dry oven. The moisture content change was used to determine the emission bake-out of the composites. Best bake-out time results were obtained with after 7 days all composites. Formaldehyde emission values of composites decreased with decreasing moisture content for both temperatures. The formaldehyde emission results of bake-out temperature 35 and $50^{\circ}C$ showed a similar tendency.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.140.1-140.1
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• 2015

Currently, As Plasma application is expanded to the industrial and medical industrial, Low temperature plasma characteristics became important. Especially in Medical industrial, Low temperature plasma directly adapted to human skin, so their plasma parameter is important. One of the plasma parameters is electron density, some kinds of method to measuring electron density are Thomson scattering spectroscopy and Millimeter-wave transmission measurement. But most methods is expensive to composed of experiment system. Heterodyne interferometer system is cheap and simple to setting up, So we tried to measuring electron density by Laser heterodyne interferometer. To measuring electron density at atmospheric pressure, we need to obtain the phase shift signal. And we use a heterodyne interferometer. Our guiding laser is Helium-Neon laser which generated 632 nm laser. We set up to chopper which can make a laser signal like a pulse. Chopper can make a 4 kHz chopping. We used Needle jet as Ne plasma sources. Interference pattern is changed by refractive index of electron density. As this refractive index change, phase shift was occurred. Electron density is changed from Townsend discharge's electron bombardment, so we observed phenomena and calculated phase shift. Finally, we measured electron density by refractive index and electron density relationship. The calculated electron density value is approximately 1015~1016 cm-3. And we studied electron density value with voltage.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.453-459
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• 2018

Purpose : This study was to investigate the change of accommodative functions by different color density and color of colored lenses. Methods : Participant had a normal NPC and no dyschromatopsia, phoria and eye disease, also had no histories of eye surgery in 31 students of university. Their accommodative functions were measured according to 50%, 80% density of the gray, blue, brown lens and non-colored lenses. Tests of accommodative functions performed include amplitude of accommodation, accommodative facility, relative accommodation, and accommodative lag. Results : The amplitude of accommodation and accommodation lag were increased when wearing the colored lens. Negative relative accommodation was more increased when wearing the colored lens than achromatic. Positive relative accommodation increased when wearing the blue color lens density by 50%. Also, accommodation facility increased when wearing the colored lens, but, as the density of the color increased, the accommodation facility was decreased. Conclusion : As since the accommodation function changes according to density of the colored lenses, working distance and environment of the wearing colored lens should be considered when selecting density and color of colored lenses.