• Korean journal of applied entomology
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• v.36 no.3
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• pp.215-223
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• 1997

A matrix model of rice weevil population based on degree day (DD) was constructed. The basic matrix model predicted on exponential jncrcase of the adult weevil density and the finite rate of increase(h) of the population was estimated to be 2.155/100DD. Adult density simulated by the matrix model including intraspecific competition showed a damped oscillation over time and reached at the stationary level of 530 at 69, 300DD. The experimental population showed similar features to that of the model. But there were some differences in the highest density and period of adult oscillation. The differences could largely be caused by the assumption of the model; resource constancy.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1421-1428
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• 2000

Objectives : The aim of this study is to evaluate the sequential metabolic changes in experimental hydrocephalus and the clinical applicability to the diagnosis and prognosis of hydrocephalus using proton MR spectroscopy. Methods : Hydrocephalus was experimentally induced in 30 cats(2-3kg body weight) by injecting 1ml of sterile kaolin suspension(250mg/ml) into the cisterna magna. Proton MRS was performed with a 1.5 T MRI/MRS unit (Vision Plus, Siemens) at pre-treatment and at 1, 3, 7, 14, 21, and 28 days after the kaolin injection. PRESS(TR/TE＝1500/270msec) technique was employed. The major metabolites which include N-acetyl aspartate (NAA), creatine(Cr), choline(Cho), and lactate(Lac) were quantitatively analyzed and the relative concentrations ratios were evaluated. Multislice $T_2$-weighted images were also obtained using fast spin echo sequence(TR/TE＝ 2500/96msec) to monitor the morphologic changes along with progression of hydrocephalus. Results : Hydrocephalus was successfully induced in all 30 cats. Twenty five cats died within 3 days and one at the end of the second week. In all animals, the NAA/Cr ratios initially decreased during the acute stage. In 4 surviving cats, the NAA/Cr ratios initially decreased during the acute stage(<14 days) and then gradually increased to the prekaolin level as follows : pre-kaolin($1.49{\pm}0.04$), day 1($1.11{\pm}0.07$), day 7($1.17{\pm}0.04$), day 14($1.40{\pm}0.03$), day 21 ($1.46{\pm}0.06$), day 28($1.43{\pm}0.03$). These levels were relatively well correlated with the symptomatologic improvement. Lactate peak, which reflects the evidence of ischemia, did not appear throughout the entire period except in one case which expired at the end of the second week. Conclusions : The NAA/Cr ratio of the sequential proton MRS in kaolin-induced hydrocephalic cats reflects a metabolic aspect of the hydrocephalus at each stage. A decreased NAA level at the early stage is from both neuronal and axonal damage which may provide diagnostic information in the acute stage of hydrocephalus. In addition, the initial fall of NAA/Cr ratio and recovery in the late stage, when no lactate peak emerges, may suggest that the main insult of the parenchyma is not to the neuron itself but to the axon, which may be related to a good prognosis. However, emergence of the lactate peak and unrecoverable NAA/Cr at the end of the acute phase may be a poor prognostic factor. In the chronic stage, recovery of NAA/Cr ratio may provide a diagnostic clue for the differentiation between hydrocephalus and cortical atrophy.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.4
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• pp.321-328
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• 2008

In this paper, we propose the hardware architecture of two-dimensional discrete wavelet transform (2D DWT) and quantization for using JPEG2000. Color 2-D DWT processor is proposed that is to apply to JPEG 2000 Hard-wired Encoder. JPEG 2000 DWT processor uses the Daubechies' (9,7) bi-orthogonal filter, and we design by minimizing error of the DWT transformer by ${\pm}1$ LSB during compression and decompression. We designed the DWT filters that using by using shift and adder structure instead of multiplier structure which raise the hardware complexity. It is improve the operation speed of filters and reduce the hardware complexity. The proposed system is designed by the hardware description language Verilog-HDL and verified by Synopsys Design Analyzer using TSMC 0.25${\mu}m$ ASIC library.

• Journal of the Korean Wood Science and Technology
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• v.35 no.4
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• pp.14-20
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• 2007

The properties of the wood pellets from damaged wood by forest fire and sound woods were investigated. Oven-dry densities of pellets made from sound wood and the damaged wood of Pinus densiflora were 0.93~0.94 and 0.86~0.88, respectively. Compressive strength of the pellets from the woods was ranged from 145 to $168kgf/cm^2$, and there was little difference between the sound wood and the damaged wood of P. densiflora. Ash content for the sound wood and the damaged wood of Pinus densiflora were 0.32~0.37% and 0.25~0.35%, respectively, and calorific values of each pellet were ranged from 18 to 19 MJ/kg. The result of elemental analysis in carbon. hydrogen and oxygen showed 45.8~48.8%, 6.2~6.5% and 46.5~48.0%, respectively. Consequently, there seem no significant difference in the properties between damaged and sound wood pellets.

• The Korean Journal of Soil Zoology
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• v.4 no.2
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• pp.75-80
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• 1999

Two years-study with litter bag (mesh size : 0.4 mm, 1.7 m) was carried out from Nov., 1996 to Sept., 1998 to investigate the soil microarthropod community in the process of needle leaf secomposition of Korean pine (Pinus koraiensis) forest in Namsan and Kwangreung, where were supposed to be under different environmental selective pressures. Soil arthropoda collected from litter bags were sorted into suborders or higher taxa. Acari and Collembola were dominant groups, which were 61-68% and 27-35% of total soil arthropod in their numbers, respectively. Among Acari, Oribatida was major group, and Gamasida and Actinedida were minor groups. Abundance of Acari was a little higher in Kwangreng than in Namsan. But there was not significant difference between the arthropod community structure of Namsan and Kwangreng forest. And the different mesh sizes (0.4 mm and 1.7 mm) of litter bags could not make significantly different community structures in the litter bags. One taxon showed different pattern of population dynalics from another. But Oribatida, Gamasida and Collembola showed peak density in July, 1997. All taxa showed lower population densities in cold season i.e. Nov., Jan. and March. There was not significant difference in decomposition rate between Namsan and Kwangreng forest, and between mesh sizes of litter bags. % residual mass of needle leaf was about 40% at 22 months after litter fall.

• Journal of the Korean Wood Science and Technology
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• v.15 no.2
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• pp.90-98
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• 1987

In the present paper I described the relations of wood ray indicators such as ray height, ray width, number of rays per $0.25mm^2$, ray spacing and fusiform ray height on the stem of Pinus koraiensis and Larix leptolepis grown at the Experiment Forest of Kangweon National University. The results may be summarized as follows. 1. The number of rays and ray spacing were generally decreased with the increase of ray height on the sample woods. 2. According to the tree species the patterns of varition of ray width with the increase of ray height were different, namely the relation between ray width and ray height showed some positive correlation on Pinus koraiensis and negative on Larix leptolepis. 3. It was recognized that the variation of fusiform ray height due to the increase of ray height indicated two patterns(the increasing, md constant regions) in sample woods. This boundary seemed to appear at six cells of ray height on Pinus koraiensis and ninc cells on Larix leptolepis. 4. The relation between fusiform ray height and number of rays had a negative correlation on Pinus koraiensis, but this tendancy was not obvious on Larix leptolepis. And ray spacing and ray width due to the increase of fusiform ray height were generally decreased. 5. On the whole the values of ray spacing and ray width became gradually larger in proportion to the increase of number of rays. 6. According to the increase of ray spacing the values of ray width also increased gradually. But this tendency was more clear on Pinus koraiensis than larix leptolepis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.18
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• pp.28-53
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• 1975

Experiments on the physiological root activity and its related characteristics of rice varieties were carried out in order to obtain some basic informations for the application of the results obtained to a rice breeding program. A significant positive correlation was found not only among the various characteristics related to conducting and ventilating systems which connects top and root of rice plant, but also between these characteristics and root activity. On the other hand, a significant difference in physiological root activity was recognized among different varieties and also between different groups of recognized 7 rice varieties differing in the their origin. It was also found that varieties with higher root activity (root activity indices) after ear formation stage tended to have more number of lower green leaves and consequently resulted in higher grain yield. Therefore, it may be possible to diagnose indirectly the root activity by examining the number of green leaves of the rice plant at later growth stage when breeders make selections of parent material for crossing or of hybrid lines in pedigree nurseries.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.215-224
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• 2013

We clarified the background for establishment of vegetation by comparing the spatial distribution maps of vegetation and substrate on a gravel bar in the Bangtae stream located on Inje-gun of Gangwon-do, the central eastern Korea. The total vegetation coverage was higher in the interior and lower in the marginal parts of the gravel bar. Spatial distribution of vegetation on the longitudinal section of the gravel bar tended to be arranged in the order of shrub, subtree, and tree dominated vegetation types from the front (upstream) toward the rear (downstream) parts. Coverage of the herbaceous plants was higher in the central and rear parts and lower in the front and right parts of the gravel bar. Vegetation height was higher in the rear part and became lowered as move toward the front part. Substrate was distributed in the order of boulder, gravel, sand, and boulder from the front toward the rear parts. Ordination of stands based on vegetation data was arranged in the order of annual plant, perennial herb, shrub, and tree dominated vegetation as move from the right to the left parts on the axis I. Species richness was higher in the order of Pinus densiflora community, Phragmites japonica community, Salix gracilistyla community, Fraxinus rhynchophylla community, annual plant dominated vegetation, and Prunus padus for. padus community based on the species rank-abundance curve. The order based on the Shannon's index was some different; diversity of Phragmites japonica community and Salix gracilistyla community, which showed higher dominance degree, were low differently from species richness. In conclusion, it was evaluated that the gravel bar newly established toward the upstream and vegetation dynamics of the gravel bar seemed to follow ecosystem mechanisms of succession. As were shown in the above results, the Bangtae stream corresponded to the upstream and thereby particle size of substrate was big. Therefore, they move by rolling and are accumulated for the upstream. Vegetation types were arranged in the order of woodland, shrub-land and grassland from the rear toward the front parts of the gravel bar and thereby reflected the formation process of the bar. However, the gravel bar is disturbed frequently by not only the running water but also the suspended sand as the dynamic space. Such disturbances cause habitat diversity and consequently led to high biodiversity.

• Clinical and Experimental Pediatrics
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• v.45 no.11
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• pp.1381-1388
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• 2002

Purpose : Magnetic resonance cholangiopancreatography(MRCP) is a noninvasive method for imaging the pancreaticobiliary tree. The aim of this study was to evalute the usefulness of MRCP for the diagnosis of pancreaticobiliary diseases in children. Methods : From October 1996 to May 2001, 67 patients with obstructive jaundice and three patients with chronic recurrent pancreatitis were evaluated with abdominal ultrasonography and MRCP. The final diagnosis was based on the operative and pathologic findings with biopsy specimen including clinical and laboratory findings. Results : A total of 70 patients, consisting of 31 males and 39 females, with a mean age of $2.6{\pm}3.3$ years were studied. The final diagnosis was biliary atresia in 25, neonatal cholestasis in 18, choledochal cyst without anomalous pancreatobiliary duct union(APBDU) in nine, choledochal cyst with APBDU in seven, cholestatic hepatitis in five, chronic recurrent pancreatitis in three, sclerosing cholangitis in two, and secondary biliary cirrhosis in one case. The overall diagnostic accuracy of abdominal ultrasonography was 75.7% and that of MRCP was 97.1%. The sensitivity and specificity of MRCP were 100% and 98% for biliary atresia, 87.5% and 100% for choledochal cyst with APBDU, 100% and 100% for choledochal cyst without APBDU, sclerosing cholangitis and chronic recurrent pancreatitis, respectively. Conclusion : MRCP is a fast, non-invasive and reliable method for diagnosing pancreaticobiliary diseases in children and will be the standard diagnostic procedure in the future.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.163-169
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• 2005

Photocatalytic oxidation of Cu(II)-EDTA has been studied using solar/$TiO_2$ photocatalysis as an energy source. Photocatalysis efficiency on the treatment of Cu(II)-EDTA was investigated using different types of solar collectors as well as by variation of the angles of solar collector solar light intensities, flow rates, and areas of solar collector. effect of $H_2O_2$ and types of $TiO_2$ catalyst on the treatment of Cu(II)-EDTA was also investigated. Removal of Cu(II) and DOC was favorable with a hemispherical collector than with a flat collector Removal of Cu(II) and DOC increased with increasing angles of solar collector up to $38^{\circ}$. Slurry type $TiO_2$ showed four-times higher removal efficiency than immobilized type $TiO_2$. Removal of both Cu(II) and DOC at a clear sky of solar light intensity ranging from 0.372 to $2.265\;mW/cm^2$ was greater than removal at a cloudy day of solar light intensity ranging from 0.038 to $1.129\;mW/cm^2$. From the result of this research that the removal efficiency of Cu(II) and DOC increased as the solar light intensity increased, it can be inferred that quantum yield in the destruction of Cu(II)-EDTA may directly related with the solar light intensity. Removal of Cu(II) increased as increasing the area of solar collector and was similar at lower flow rates white removal of Cu(II) was interfered at higher flow rates. When immobilized $TiO_2$ was used, removal efficiency of Cu(II) increased in the presence of $H_2O_2$ while negligible effect was found in the use of $TiO_2$ slurry.