• Journal of Korean Society of Forest Science
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• v.32 no.1
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• pp.29-35
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• 1976

In order to estimate sawmill productivities, rates of technical change and optimum combination of production factors, Cobb-Douglas production functions have been derived using data obtained from 96 sample mills in Busan-Incheon, southwestern and northeastern areas. The results may be summarized as follows: 1. There is a tendency of expanding average sawmill size in the areas. The horse-power holdings per mill have been increased at the rates of 91 percent in Busan-Incheon, 7.7 percent in southwestern and 16.9 percent in northeastern areas. This implies that the mills around log-importing ports have made rapid development, compared with those in forest regions. 2. The regression coefficients (production elasticities) of the functions for the year of 1967 in the above three areas are much similar each other, but significant differencies are found in the production functions of 1975. In other words, sawmill productivity was mainly restricted by capital deficiencies in all areas in 1967, but this situation was succeeded only by N-E area in 1975. The range of sum of regression coefficients is 1.0437-1.4214, this indicates increasing rates of return to scale. 3. The annual rates of technical changes in B-I, S-W and N-E areas for the observed period are 17.6, 7.6 and 2.2 percents respectively. Busan-Incheon is the only area where labor productivity is higher than that of capital. 4. The best combination of production factors for maximizing firm's profit is subject to the changes of input and output prices. With some assumptions of prices and costs, the optimum levels of power and labor input in B-I, S-W and N-E areas are 57:17, 427:94 and 192:27.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.285-293
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• 2018

This study aimed to evaluate the effect of height suppression of cucumber and tomato plug seedlings as affected by mechanical stimulus using brushing as environment-friendly method. Cucumber (Cucumis sativus L. 'Joeunbaekdadagi') and tomato (Solanum lycopersicum L. 'Mini Chal') seeds were sown in 40-cell plug trays ($54{\times}27.5{\times}5cm$) filled with growing medium on Oct. 9, 2017. The cultivation environment in a venlo-type glasshouse was maintained as cultivation temperature range of $15-25^{\circ}C$ and the relative humidity of $50{\pm}10%$. Nontreatment and diniconazole ($7.5mg{\cdot}L^{-1}$) application at 15 days after sowing were used as the control. In addition, brushing treatments in cucumber and tomato were applied interval of 2, 4 or 6 hrs for 15 and 20 days, respectively. Plant height, hypocotyl length, and internode length were inhibited for cucumber and tomato in the diniconazole treatment than in the control. The leaf size was reduced, both cucumber and tomato, while the SPAD increased under the diniconazole treatment. However, stem diameter of cucumber was the thickest in the 2 hrs brushing interval treatment. Fresh weights of shoot and root were the significantly lowest in the diniconazole treatment. Application of brushing improved seedlings quality by promoting dry weights of shoot and root, and compactness of tomato seedlings. The chlorophyll fluorescence of tomato seedlings drastically decreased with 2 hrs treatment, indicating that mechanical stress by brushing treatment. The relative growth rate of tomato seedlings was significantly lower in the diniconazole treatment, but cucumber seedlings were not significantly different in all treatments. As a results, height suppression of cucumber and tomato seedlings was best achievement in the diniconazole treatment by the chemical as growth regulator. In an environment-friendly point of view, however, it is considered that 2 hrs brushing interval treatment can be the applicability for replacing the chemical methods in plug seedling growth of cucumber and tomato.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.302-311
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• 2018

Using cylindrical paper pot nursery method, three kinds of commercial tomatoes 'Dafnis', 'DOTAERANG DIA' and 'Maescala' were grafted onto a commercial rootstock 'B blocking'. From 10 to 40 days after graft-take, growth traits of seedlings were investigated by 0.5, 1.0 and 2.0S treatments of standard nutrient solution(S) for seedling growth, and top to root ratio(TRR), compactness(CP) and Dickson Quality Index(DQI) were calculated. Two weeks after transplanting of the seedlings under three different night temperature targeting to 10, 15, and $25^{\circ}C$, which were not precisely controlled, the relative growth rate (RGR) was investigated. The quantitative growth traits of grafted seedlings increased with increasing fertilizer concentration, and various range of seedling size could be produced. Compactness and DQI were significantly regressed (Adj $R^2=0.9480$). Short-term RGR after transplanting was higher at 1.0S treatment of standard nutrient solution at the seedling age of 30 days and 40 days after graft-take(DAGT). DQI and RGR were significantly regressed linearly at respective fertigation strength. Specially the diminishing slope of RGR was lower at 1.0S fertigation strength with the increase of DQI than others. The results indicate that DQI could be applied as a quality index of grafted tomato seedlings and the relation analysis between DQI and short-term RGR also could be used to determine the good quality seedlings of grafted tomato grown in cylindrical paper pot.

• Investigative Magnetic Resonance Imaging
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• v.13 no.1
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• pp.74-80
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• 2009

Purpose : To evaluate the characteristic MR imaging findings of Langerhans cell histiocytosis (LCH) in the skull and to compare them with those of plain radiography and computed tomography. Materials and Methods : A total of 10 lesions in 9 patients (Age range; 5-42 years, Mean age; 18, all women) with Langerhans cell histiocytosis in the skull were included in our study. Nine lesions in nine patients were histologically confirmed by surgery or fine needle aspiration biopsy. All patients performed with MRI, and plain radiography and CT scan were done in 7 patients (8 lesions). Two experienced neuroradiologists reviewed the radiological examinations independently with attention to location, size, shape and nature of the lesions in the skull and compared the extent and extension of the lesions to adjacent structures. Results : The lesions were distributed in all of the skulls without predilection site. On MRI, the masses were shown as well-enhancing soft tissue masses (10/10) mainly in diploic spaces (8/10) with extension to scalp (9/10) and dura mater (7/10). Dural enhancement (7/10) and thickening (4/10) were seen. The largest diameter of the soft tissue masses ranged 1.1 cm to 6.8 cm, shaped as round (5/10) or oval (5/10). On CT scans, the lesions were presented as soft tissue masses involving diploic space (6/8) and scalp extension (7/8) were also well visualized. Although bony erosion or destruction was more clearly seen on CT rather than those of MRI, enhancement of soft tissue masses and dura were not well visualized on CT. In contrast, all of the lesions in LCH were seen as punched out (4/8), beveled-edge appearance (4/8) osteolytic masses in plain radiography, but scalp and dural extension could not be seen. Conclusion : Characteristic MR findings in patients with LCH are soft tissue mass in diploic space with extension to dura and scalp, and MRI would be better imaging modality than plain radiography or CT.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.604-619
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• 2012

According to the concept of woodland aesthetic in Germany and forest design in United Kingdom, artificial forest should be restore ecologically step by step in National Park, Korea. This study was carried out to provide the density criterion of thinning for the inducement of the ecological succession by analysing of vegetational structure in Artificial Forest, National Parks. Eleven plots(size is $20m{\times}20m$) were set up in the artificial forest such as Pinus koraiensis forest, Abies holophylla forest, Chamaecyparis obtusa forest, Populus tomentiglandulosa forest, and Larix kaempferi forest and in the natural forest such as Pinus densiflora community, Pinus densiflora-Quercus serrata community, and Quercus serrata community in Chiaksan, Songnisan, Deogyusan, and Naejangsan National Parks, Korea. We classified the artificial forest into undeveloped type of succession, type of alien young trees developing, and early phase type of succession based on the vegetational structure. According to the index of Shnnon's diversity(unit: $400m^2$), undeveloped type of succession was ranged from 0.9681 to 1.1323, type of alien young trees developing was ranged from 1.0192 to 1.1870, early phase type of succession was ranged from 1.3071 to 1.3892, and natural vegetation was ranged from 1.2202 to 1.3428, therefore early phase type of succession forest and natural vegetation are more higher than simple-layered artificial forest with one needle leaf tree species. The limit for the step-by-step thinning was in the range of 30~60%. In case of undeveloped type of succession, we should thin out from large trees throughout three phases, because alien species dominated high value 88~90% in canopy layer. In case of type of alien young trees developing, we should thin out from alien young trees such as Populus tomentiglandulosa throughout one or two phases, because alien species dominated high value 60~97% and young trees with saplings growing up in understory and shrub layer. In case of early phase type of succession, we should thin out from alien trees that compete with native species throughout one or two phases, because alien species dominated less than value 30%.

• Journal of Radiation Protection and Research
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• v.33 no.2
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• pp.47-51
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• 2008

Objective: This study analyzed errors due to rotation or tilt of the magnetic resonance (MR) imaging indicator during image acquisition for a stereotactic radiosurgery. The error correction procedure of a commercially available stereotactic neurosurgery treatment planning program has been verified. Materials and Methods: Software virtual phantoms were built with stereotactic images generated by a commercial programming language, Interactive Data Language (version 5.5). The thickness of an image slice was 0.5 mm, pixel size was $0.5{\times}0.5mm$, field of view was 256 mm, and image resolution was $512{\times}512$. The images were generated under the DICOM 3.0 standard in order to be used with Leksell GammaPlan$^{(R)}$. For the verification of the rotation error correction function of Leksell GammaPlan$^{(R)}$, 45 measurement points were arranged in five axial planes. On each axial plane, there were nine measurement points along a square of length 100 mm. The center of the square was located on the z-axis and a measurement point was on the z-axis, too. Five axial planes were placed at z=-50.0, -30.0, 0.0, 30.0, 50.0 mm, respectively. The virtual phantom was rotated by $3^{\circ}$ around one of x, y, and z-axis. It was also rotated by $3^{\circ}$ around two axes of x, y, and z-axis, and rotated by $3^{\circ}$ along all three axes. The errors in the position of rotated measurement points were measured with Leksell GammaPlan$^{(R)}$ and the correction function was verified. Results: The image registration errors of the virtual phantom images was $0.1{\pm}0.1mm$ and it was within the requirement of stereotactic images. The maximum theoretical errors in position of measurement points were 2.6 mm for a rotation around one axis, 3.7 mm for a rotation around two axes, and 4.5 mm for a rotation around three axes. The measured errors in position was $0.1{\pm}0.1mm$ for a rotation around single axis, $0.2{\pm}0.2mm$ for double and triple axes. These small errors verified that the rotation error correction function of Leksell GammaPlan$^{(R)}$ is working fine. Conclusion: A virtual phantom was built to verify software functions of stereotactic neurosurgery treatment planning program. The error correction function of a commercial treatment planning program worked within nominal error range. The virtual phantom of this study can be applied in many other fields to verify various functions of treatment planning programs.

• Journal of the Korean Magnetics Society
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• v.5 no.4
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• pp.269-274
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• 1995

The basic composition of Mn-Zn ferrite was $Mn_{0.631}Zn_{0.316}Fe_{2.053}O_{4}$(specimen A), $Mn_{0.584}Zn_{0.312}Fe_{2.104}O_{4}$(specimen B) and $Mn_{0.538}Zn_{0.308}Fe_{2.154}O_{4}$(specimen C) with additional 0.1 mol % $CaCo_{3}$ and 0.04 mol % $V_{2}O_{5}$. For high per¬meability and acceleration of grain growth, $CaCo_{3}$ and $V_{2}O_{5}$. was added. The mixture of the law materials was calcinated at $950^{\circ}C$ for 3 hours and then milled. The compacts of toroidal type were sintered at different temperature($1250^{\circ}C$, $1300^{\circ}C$, $1350^{\circ}C$) for 2 hours in $N_2$ atmosphere. The effects of the various raw material composition and sintered temperature on the physical properties of Mn-Zn ferrite have been investigated. They turned out to be spinel structure by X-ray diffraction and the size of grain from SEM was from $18\;\mu\textrm{m}\;to\;23\;\mu\textrm{m}$. As the sintering temperature was increased from $1250^{\circ}C$ to $1350^{\circ}C$, the initial permeability and magnetic induction has increased and the both of Q factor and coercive force has decreased. The coercive force and curie temperature were almost the same at each specimen Their values were about 0.45 Oe and $200^{\circ}C$. The frequency of specimen will used in the range from 200 kHz to 2 MHz. The basic composition of $Mn_{0.584}Zn_{0.312}Fe_{2.104}O_{4}$(specimen B) sintered at $1300^{\circ}C$ shows the best results at magnetic induction (Br & Bm).

• Food Science and Preservation
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• v.22 no.1
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• pp.63-69
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• 2015

The highly producible rice cultivars, hanareum and dasan 2, were prepared and investigated for their physicochemical properties, and the quality characteristics of frozen cookie dough with rice flour according to the thawing time were measured. The water, ash, crude protein, amylose, and damaged starch contents of rice flour, as well as its water holding capacity, particle size, and Hunter color value, were measured. The water, ash, and crude protein contents of the hanareum and dasan 2 rice flours were shown to range from 7.28 to 13.14%, from 0.35 to 0.39, and from 6.05 and 8.68%, respectively. The protein content of the control group was higher than that of hanareum and dasan 2 rice flours. The amylose contents of the hanareum and dasan 2 rice flour were 19.05 and 23.04%, respectively. The damaged starch content and water holding capacity of the control group were lower than those of the hanareum and dasan 2 rice flours. The particle sizes of the samples were $48.54{\sim}50.05{\mu}m$. The lightness values of the hanareum, and dasan 2 rice flour, and of the control were 93.72, 93.51 and 92.63, respectively. The quality characteristics of the gluten-free frozen cookie dough were investigated. The lightness of the cookie made with frozen cookie dough decreased according to the by thawing time, but the diameter of the cookie did not differ significantly. The hardness of the cookie made with rice frozen dasan 2 rice dough was lower than that of the cookie made with frozen hanareum rice dough.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.313-324
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• 2009

We explore the effect of particle shape and size on 3-dimensional (3D) network and pore structure of porous earth materials composed of glass beads and silica gel using NMR micro-imaging in order to gain better insights into relationship between structure and the corresponding hydrologic and seismological properties. The 3D micro-imaging data for the model porous networks show that the specific surface area, porosity, and permeability range from 2.5 to $9.6\;mm^2/mm^3$, from 0.21 to 0.38, and from 11.6 to 892.3 D (Darcy), respectively, which are typical values for unconsolidated sands. The relationships among specific surface area, porosity, and permeability of the porous media are relatively well explained with the Kozeny equation. Cube counting fractal dimension analysis shows that fractal dimension increases from ~2.5－2.6 to 3.0 with increasing specific surface area from 2.5 to $9.6\;mm^2/mm^3$, with the data also suggesting the effect of porosity. Specific surface area, porosity, permeability, and cube counting fractal dimension for the natural mongolian sandstone are $0.33\;mm^2/mm^3$, 0.017, 30.9 mD, and 1.59, respectively. The current results highlight that NMR micro-imaging, together with detailed statistical analyses can be useful to characterize 3D pore structures of various porous earth materials and be potentially effective in accounting for transport properties and seismic wave velocity and attenuation of diverse porous media in earth crust and interiors.

• The Korean Journal of Financial Management
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• v.27 no.1
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• pp.181-208
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• 2010

In July 2007, Korean government has passed "The Capital Market and Financial Investment Services Act" to further develop the capital markets and the Act was to become effective in February 2009. Using a large sample of Korean firms, we have examined (i) the effect of underwriting activities on the firm value (bond spread) comparing commercial bank and investment bank, and (ii) the determinants of the firm value changes following underwriting activities of bank. To test our goal, we collected a wide range of samples of data for bond issuing activities executed by Korean firms listed on the Korea Stock Exchange (KSE) between 2000 and 2003. Our paper is distinguished from previous studies on this subject in a way that we analyzed the effect of corporate bond underwriting activities with regard to commercial banking and investment banking. Initially, we set up a hypothesis that "Certification View" and "Conflict-of-interest View" are major driving forces behind cross-firm differences in performance following bond issuance. We find that, in general, underwriting by investment bank (securities company) brings a positive effect on the firm value (spread between bench mark rate and bond issuing rate). This result indicates that firm value has been negatively affected by the bank underwriting and provides the evidence for "Conflict-of-interest View" in Korea. Our studies have also revealed that any change in firm value following bond issuance is positively related with the firm size (total asset), operating performance, liquidity (cashflow), and equity ownership by foreign investors. Overall, our results support the view that bank underwriting activities can play an important role in determining firm value and financial strategies under "The Capital Market and Financial Investment Services Act" of 2007.