• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.172-180
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• 2007

Among the nuclear medicine imaging methods available today, $H_2^{15}O-PET$ is most widely used by cognitive neuroscientists to examine regional brain function via the measurement of regional cerebral blood flow (rCBF). The short half-life of the radioactively labeled probe, $^{15}O$, often allows repeated measures from the same subjects in many different task conditions. $H_2^{15}O-$ PET, however, has technical limitations relative to other methods of functional neuroimaging, e.g., fMRI, including relatively poor time and spatial resolutions, and, frequently, insufficient statistical power for analysis of individual subjects. However, recent technical developments, such as the 3-D acquisition method provide relatively good image quality with a smaller radioactive dosage, which in turn results in more PET scans from each individual, thus providing sufficient statistical power for the analysis of individual subject's data. Furthermore, the noise free scanner environment $H_2^{15}O$ PET, along with discrete acquisition of data for each task condition, are important advantages of PET over other functional imaging methods regarding studying state-dependent changes in brain activity. This review presents both the limitations and advantages of $^{15}O-PET$, and outlines the design of efficient PET protocols, using examples of recent PET studies both in the normal healthy population, and in the clinical population.

• Journal of the Korean Society for Railway
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• v.17 no.3
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• pp.201-209
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• 2014

Transit Oriented Development(TOD) has been the dominant paradigm for urban development. The traditional approach to the development of urban rail station areas demonstrates apparent weaknesses when it comes to compact and mixed-use types of development for these stations. Thus, the objective of this study is to derive evaluation indicators with which to assess urban rail station areas using TOD planning elements. A focus group interview was conducted to explore TOD planning elements. In order to examine the level of TOD to be achieved, an AHP technique was utilized to analyze the importance of several variables. Z-scores and Re-scores were applied to derive the values for the stations. The Variables related to the land use type, mixed use, floor area, and public transit were found to be the major contributing factors to the achievement of TOD in urban rail station areas. The results of this study show that the level of TOD achievement varies according to the major land use, density, accessibility, and mixed-use planning elements.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.101-109
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• 1996

This study was done to find out the methods of long-term use of liquid boar semen in 100 ml plastic bottle for artificial insemination and to investigate differences between Lactose-Egg yolk and Biitschwiler diluents according to storage temperature, and effect of final glycerol concent ration in Lactose-Egg yolk diluent. Liquid boar semen diluted with Lactose-Egg yolk diluent showed significantly higher sperm motility (p<0.05) after 0.5 and 2h incubation at 37$^{\circ}C$,than Butschwiler diluent at all storage length when it was preserved in the 5$^{\circ}C$ refrigerator. The NAR acrosome in Lactose-Egg yolk diluent a after 0.5 and 2h incubation at 37$^{\circ}C$, respectively, during preservation periods was similar to that in Biitschwiler diluent. When liquid boar semen was preserved at 15$^{\circ}C$, liquid boar semen in the Butschwiler diluent showed significantly higher percentages of sperm motility and NAR acrosome from third day to seventh than that in Lactose-Egg yolk diluent. In the effect of final glycerol concentration of liquid boar semen in the Lactose-Egg yolk diluent, the final glycerol concentration of 2% showed higer percentages of sperm motility and NAR acrosome than that of 0, 1, 3, and 5%. Farrowing rate, litter size and average pig weight at birth did not differ significantly between Lactose-Egg yolk and But schwiler diluents. As a result of this study, we found out that liquid boar semen can be stored for 6-7 days at 5$^{\circ}C$ in Lactose-Egg yolk diluent and at 15$^{\circ}C$ in Butschwiler diluent.

• Korean Journal of Environment and Ecology
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• v.31 no.3
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• pp.318-328
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• 2017

In order to provide basic data for the ecological management of forest vegetation in Southern Naeyeon Mountains, A total of 149 sample plots were selected and vegetation survey was carried out by the phytosociological method of the ZM school to classify vegetation types and to grasp ecological characteristics. The forest vegetation was divided into 10 types in terms of species composition, and had a unit hierarchy of 2 community groups, 4 communities, 6 sub-communities and 6 variants. A total of 19 types of physiognomic vegetation were identified based on uppermost dominant species, of which 18 were natural vegetation and 1 was artificial vegetation. As a result of the analysis of the importance values of constituent species, Quercus mongolica, a potentially natural vegetation element, was found to be relatively more important in most stands than other species, and excluding the artificial interference, most of the areas except for some sites would be changed to Q. mongolica forest. In order to understand the spatial distribution of forest vegetation, 1/5,000 large-scale physiognomic vegetation map was created by the uppermost dominant species. As a result, natural vegetation accounted for 98.2%, the number of vegetation patches was 733 and the average area per patch 3.93ha.

• Journal of Korean Society of Forest Science
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• v.107 no.3
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• pp.245-257
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• 2018

The study was carried out to discover the forest vegetation structure in Hongdo Island, Jeonnam province. Vegetation data were collected by total of forty one quadrate plots using Z-M phytosociological method from June to August in 2017, and analyzed by vegetation classification, mean importance value and species diversity. As a result of vegetation type classification, Castanopsis sieboldii community group was classified at a top level of vegetation hierarchy. In the level of community, it was classified into Neolitsea sericea community and Carpinus turczaninowii community. N. sericea community was subdivided into Ficus erecta group(Vegetation unit 1) and Arisaema ringens group(VU 2). C. turczaninowii community was subdivided into Fraxinus sieboldiana group(VU 3) and C. turczaninowii typical group(VU 4). Therefore, it was classified into total of four vegetation units(one community group, three communities and four groups). As a result of mean importance value, Castanopsis sieboldii was the highest in VU 1, VU 2, VU 4, and C. turczaninowii in VU 4, respectively. In case of species diversity, VU 3 showed the highest among four units in species diversity index. In conclusion, the forest vegetation of Hongdo Island was classified into four units and seven species groups. Hongdo Island could be conclusively managed by community ecological approach for the units and groups. Also it was considered that a research for the succession to the evergreen broad-leaved forest should be more intensively proceeded near future.

• Korean Journal of Environment and Ecology
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• v.29 no.5
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• pp.791-802
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• 2015

The study was carried out to analyze vegetation structure of Mt. Eungbok located in Jochimryeong to Shinbaeryeong of the Baekdudaegan mountain range. The survey for 25 plots was conducted from April 2012 to August 2013 in the permanent plots using phytosociological analysis. As a result, the vegetations were classified into four vegetation units. In species composition, they were classified into Quercus mongolica community group divided into 2 community such as Ulmus laciniata community and Corylus sieboldiana var. mandshurica community, U. laciniata community was subdivided Rhododendron schlippenbachii group and Rubus crataegifolius group(into Viola albida subgroup, Rubus oldhamii subgroup). In terms of Importance values according to layer-specific and altitude of ridge, Q. mongolica was the highest importance value of tree layer and Acer pseudosieboldianum was highest importance value of sub tree layer. Therefore Q. mongolica and A. pseudosieboldianum could likely remain in the future of tree layer and sub tree layer respectively. Analysis of dominance most value of vegetation are on about 0.3. In ridge area was a species diversity result, vegetation unit 3 showed the highest value 0.974 and vegetation unit 1 showed the lowest value 0.725. Based on the interspecific association showed four types which were coincident with differential species and character species on the constancy table. Specially type I plant species were mostly differential species and the characteristic species, which appeared in the Rhododendron schlippenbachii community classified phytosociologically, and type III plant species were mostly the species appearing in the Corylus sieboldiana var. mandshurica community growing in the relatively.

• Applied Biological Chemistry
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• v.14 no.1
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• pp.19-27
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• 1971

This experiment was conducted as a preliminary test to invent the quick ripening process for soysauces. The bran koji extract of 2 kinds of mold (Asp. niger and Asp. sojae) was used as enzyme sources in order to improve the rate of enzymatic conversion of raw materials and shorten the ripening period of soysauces. Soybean koji (inoculated Asp. sojae) and steamed soybean were enzymatically decomposed for 8 hours at $40^{\circ}C$, pH 4-6 with stirring at a rate of 1500 rpm. After the enzymatic treatment, soysauces were fermented by 4 kinds of processes with the above-mentioned salt tolerant microorganisms inoculated. After 4 weeks, sensory evolution for these soysauces products and analysis of chemical components were carried out. The results obtained were summarized as follows. 1. Soysauces prepared from decomposed koji by Asp. niger enzyme complex showed higher extractables, such as total nitrogen, amino nitrogen, pure extract and reducing sugar, than any other procedure. Extracted amounts of each components of soysauces prepared from this process during 1 month were similar to those of soysauces made from general procedure (control) for 5 to 6 months. 2. According to sensory evaluation, soysauce prepared from decomposed koji also showed best taste and were similar to that of soysauces prepared by general method for 6 months.

• Progress in Medical Physics
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• v.15 no.4
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• pp.215-219
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• 2004

Due to their excellence for the high-energy therapy range of photon beams, researchers show increasing interest in applying MOSFET dosimeters to low- and medium-energy applications. In this energy range, however, MOSFET dosimeter is complicated by the fact that the interaction probability of photons shows significant dependence on the atomic number, Z, due to photoelectric effect. The objective of this study is to develop a very detailed 3-dimensional Monte Carlo simulation model of a MOSFET dosimeter for radiological characterizations and calibrations. The sensitive volume of the High-Sensitivity MOSFET dosimeter is very thin (1 ${\mu}{\textrm}{m}$) and the standard MCNP tallies do not accurately determine absorbed dose to the sensitive volume. Therefore, we need to score the energy deposition directly from electrons. The developed model was then used to study various radiological characteristics of the MOSFET dosimeter. the energy dependence was quantified for the energy range 15 keV to 6 MeV; finding maximum dependence of 6.6 at about 40 keV. A commercial computer code, Sabrina, was used to read the particle track information from an MCNP simulation and count the tracks of simulated electrons. The MOSFET dosimeter estimated the calibration factor by 1.16 when the dosimeter was at 15 cm depth in tissue phantom for 662 keV incident photons. Our results showed that the MOSFET dosimeter estimated by 1.11 for 1.25 MeV photons for the same condition.

• Korean Journal of Optics and Photonics
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• v.24 no.5
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• pp.245-250
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• 2013

The Wiener-Khinchin theorem, which means that the autocorrelation function of a signal corresponds to the power spectrum of the signal, is very important in signal processing, spectroscopy and telecommunications engineering. However, because of needs for some relatively expensive equipments such as a correlator and the signal processing system, its demonstration in most undergraduate class is not easy so far. Recently, digital oscilloscopes whose functions can be replaced foresaid equipments are marketed with development of digital engineering. In this paper, a simple demonstration of the theorem is given by a digital storage oscilloscope and a personal computer with its theoretical background. The reason that deals again with this theorem which has been introduced in 1930 is that it has been not well informed yet to us and theoretical background of the demonstration is directly introduced from its driving process. Through deriving process of the theorem, some extended physical meanings of the impedance, power, power factor, Wiener spectrum, linear system response and, furthermore, basic idea of the Planck's quantization in the black body theory reveal themselves naturally. Hence it can be referred to lectures in general physics, modern physics, spectroscopy and material characterization experiment.

• The Korean Journal of Ecology
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• v.26 no.1
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• pp.23-28
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• 2003

In order to identify plant species and communities characteristic of lithospheric condition, forest vegetations of igneous(mainly granite) and sedimentary(mainly sandstone) areas in Kyungpook province were compared. We collected 108 phytosociological releves from the older forests over 20 years old. 444 vascular plant species and 25 plant communities were identified. Results of Principal Coordinates Analysis (PCA) indicated that lithospheric conditions and human impacts were the most important factors related to the plant community diversity and species richness. In the igneous rock areas net contribution degree (rNCD) of 139 species including Quercus serrata, Q. mongolica, Lindera obtusiloba and Fraxinus sieboldiana increased and those of Carpinus laxiflora and Styrax japonica decreased. In the sedimentary rock areas, to a lesser extent, 96 species including Q. aliena, Zanthoxylum schinifolium, Potentilla fragarioides var. major, Rhus javanica, and Plectranthus japonicus increased, whereas character species of Lindero-Quercion mongolicae such as Q. mongolica, Q. serrata, Rhododendron schlippenbachii, Acer mono and Styrax obassia decreased, and particularily the species Sasa borealis, the Alangium-Zelkova serrata community and the Philadelphus-Fraxinus mandshurica community were absent. The vegetation of sedimentary rock area is characterized as a regional type shaping dwarf pine forests and sparse and light broad-leaved forests.