• Journal of Korean Society of Forest Science
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• v.61 no.1
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• pp.8-14
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• 1983

This study was to diagnose the ontogenetic ability of drought tolerance in trees, and was to investigate the seasonal changes in tissue-water relations parameters, ${\pi}_o$, ${\pi}_p$, $E_{max}$, $N_s/DW$, $V_o/W_s$ and $RWC_{(tlp)}$, obtained from P-V curves on the Pinus koraiensis and Abies holophylla shoots. The results obtained are as follows; 1) Seasonal changes of original osmotic pressure at maximum turgot, ${\pi}_o$, were -1.2 to -1.6 MPa in Pinus koraiensis and -1.4 to -1.7 MPa in Abies holophylla. 2) Seasonal changes of osmotic pressure at incipient plasmolysis, ${\pi}_p$, were -1.8 to -2.1 MPa in Pinus koraiensis and -1.6 to -2.1 MPa in Abies holophylla. 3) Seasonal changes of relative water content at incipient plasmolysis, $RWC_{(tlp)}$, were 70 to 77% in Pinus koraiensis and 69 to 85% in Abies holophylla. 4) Seasonal changes of maximum bulk modulus of elasticity at maximum hydration, $E_{max}$, were 2.2 to 6.3 MPa in Pinus koraiensis and 3.1 to 7.9 MPa in Abies holophylla. 5) Seasonal changes of number of osmoles of solute in symplasm versus dry weight, $N_s/DW$, were 0.5 to 1.3 in Pinus koraiensis and 0.3 to 1.0 in Abies holophylla. 6) Seasonal changes of original osmotic water volume versus total water volume (symplasmic and apoplastic water), $V_o/W_s$, were 55 to 65%r in Pinus koraiensis and 40 to 65% in Abies holophylla. Consequently, as the comparative values of ${\pi}_o$, ${\pi}_p$, $E_{max}$, $N_s/DW$, $V_o/W_s$, and $RWC_{(tlp)}$, it might be suggested that Abies holophylla shoot could have more or less a greater ability of drought tolerance as compared with Pinus koraiensis shoot.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.854-861
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• 2008

We have described a high power hybrid envelope elimination and restoration(H-EER) transmitter for IEEE 802.16e Mobile World Interoperability for Microwave Access(WiMAX) using an efficiency optimized power amplifier(PA). The PA has been designed to have maximum PAE at the important power generation $V_{ds}$, region using Nitronex 100-W PEP GaN HEMT. For the high power application, H-EER transmitter should be considered the regenerative oscillation problem due to the PA's bias fluctuation effect and bias modulator stability issue. Therefore, the bias modulator for H-EER transmitter has been designed to suppress the regenerative oscillation. For the interlock experiment, the bias modulator has been built with the efficiency of 72% and peak output voltage of 30 V for the envelope signal with a PAPR of 8.5 dB. The H-EER transmitter for WiMAX application has been achieved a high PAE characteristic, 38.8 % at an output power of 41.25 dBm. By using digital predistortion(DPD) technique, the Relative Constellation Error (RCE) has been satisfied the specification of -34.5 dB. This is the first work at 2.655 GHz high power H-EER transmitter for WiMAX application.

• Journal of the Korean Geotechnical Society
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• v.25 no.6
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• pp.5-16
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• 2009

The is study is to evaluate the small strain shear modulus ($G_{max}$) of Busan clay using in-situ penetration tests. A series of dilatometer tests (DMT) and piezocone penetration tests (CPTu) are performed at Busan newport and Noksan sites, and hybrid oedometer tests are also carried out on the specimens obtained from both sites. The $G_{max}$ is evaluated from the shear wave velocity ($V_s$) measured by the bender elements installed at the boundary of oedometer cell. By analyzing these data, the relationship of $G_{max}$ and state variables, such as confined stress and void ratio, is developed. The analysis of lab and in-situ test results reveals that the ratio of $G_{max}$ to $q_t$ is inversely proportional to the plasticity index while the ratio of $G_{max}$ to $E_D$ has a linear relationship with ($I/I_D$)$(p_a/{\sigma}'_v)^{0.5}$. Two correlations suggested in this study, based on CPT and DMT results, appear to provide reasonable predictions of the small strain shear modulus.

• Physical Therapy Korea
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• v.6 no.2
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• pp.56-66
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• 1999

The purpose of this study focused how to show physiological responses comparing exercise group and non exercise group for progressive maximal wheelchair ergometer exercise loading in complete paraplegia. It also examined the various factors which would be influenced physiological responses. Sixteen subjects have been investigated in this study, and the subjects are divided into two groups as follows: 1) exercise group (7 subjects) 2) non exercise group (9 subjects). Each test was terminated by physical exhaustion and/or an inability to maintain a flywheel velocity. The results were as follows: 1) No difference was noted in pulmonary function test between two groups. 2) $\dot{v}$ Emax value during maximal exercise was significantly different between the groups (p<0.05). The mean $\dot{v}$ Emax of exercise group was $69.67{\ell}/min$, non exercise group was $41.47{\ell}/min$. 3) $\dot{v}$ $O_2max$(${\ell}/min$) value during maximal exercise was significantly different between the groups (p<0.05). The mean $\dot{v}$ $O_2max$(${\ell}/min$) of exercise group was $1.72{\ell}/min$, non exercise group was $1.15{\ell}/min$. 4) $\dot{v}$ $O_2$ max(ml/kg/min) value during maximal exercise was significantly different between the groups (p<0.05). The mean $\dot{v}$ $O_2max$($ml/kg{\cdot}min$) of exercise group was $25.99ml/kg{\cdot}min$, non exercise group was $18.61{\ell}/min$. 5) Maximal heart rate(HRmax) value during maximal exercise was significantly different between the groups (p<0.05). The mean HRmax of exercise group was 180.43 beats/min, non exercise group was 175.00 beats/min. 6) $\dot{v}\;E/\dot{v}\;O_2$ value during maximal exercise was not significantly different between the groups (p>0.05). The mean $\dot{v}\;E/\dot{v}\;O_2$ of exercise group was $36.36{\ell}/{\ell}\;O_2$, non exercise group was $45.46{\ell}/{\ell}\;O_2$. Considering the results which explore the exercise group with paraplegia has shown the maximal aerobic power compared with non exercise group, regular and consistent physical training is highly assumed as a main factor to improve cardiopulmonary fitness.

• Journal of the Korean Mathematical Society
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• v.38 no.1
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• pp.177-191
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• 2001

We consider a linear differential game described by the delay-differential equation in a Hilbert space H; (※Equations, See Full-text) U and V are Hilbert spaces, and B(t) and C(t) are families of bounded operators on U and V to H, respectively. A(sub)0 generates an analytic semigroup T(t) = e(sup)tA(sub)0 in H. The control variables g, and u and v are supposed to be restricted in the norm bounded sets (※Equations, See Full-text). For given x(sup)0 ∈ H and a given time t > 0, we study $\xi$-approximate controllability to determine x($.$) for a given g and v($.$) such that the corresponding solution x(t) satisfies ∥x(t) - x(sup)0∥ $\leq$ $\xi$($\xi$ > 0 : a given error).

• IMMUNE NETWORK
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• v.5 no.4
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• pp.252-257
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• 2005

Background: This study was designed to investigate the effect of exercise training on defense mechanism of chronic degenerative disease, aging, and memory impairments of senescence-accelerated mouse (SAM)P8 under the hypothesis that "Senile dementia may be prevented by regular exercises". Methods: To evaluate the effects of exercise training on the defense mechanism of aging and memory impairment, SAMP8 were divided into two groups, the control group and exercise training groups. the exercise training group were performed with low $(\dot{V}O_2max\;25{\sim}33%)$, middle ($\dot{V}O_2max$ 50%) and high $(\dot{V}O_2max\;66{\sim}75%)$ intensity exercise. All SAMP8 mice were fed experimental diet ad libitum until 4, 8 months, and dead period. Results: Median lifespan in middle exercise group resulted in a significantly increased (23.5% and 18.7%, respectively), whereas these lifespan in high exercise group resulted in an unexpectedly decreased (13.5% and 12.1%, respectively) compared with control group. Body fat levels in 4 and 8 months of age were significantly decreased 43% to 51% in middle exercise group, whereas were remarkably deceased to 57% in high exercise group compared with control group. It is believed that extended median and maximum lifespan may be effected by calory restriction through the exercise training. Acetylcholine (ACh) levels were significantly increased 6.7% and 8.5% in middle and high exercise groups, and also choline acetyltransfease (ChAT) activities were significantly increased 10.3% and 11.9% in middle and high exercise groups. Conclusion: These results suggest that proper and regular exercises such as middle group ($\dot{V}O_2max$ 50%) may play an effective role in attenuating an oxygen radicals and may play an important role in improving a learning and memory impairments of senile dementia.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.711-716
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• 2010

New electroluminescent polymers with fluoro groups in vinylene units, poly(m-silylphenyl-p-phenylene-difluorovinylene) (m-SiP-PPDFV) have been synthesized by GILCH polymerization. These polymers have been used as the electroluminescent (EL) layers in single layer light-emitting diodes (LEDs) (ITO/PEDOT/polymer/Ca:Al). m-SiP-PPDFV shows PL around $\lambda_{max}$ = 452 nm and green EL around $\lambda_{max}$ = 497 nm. The current-voltage-luminance (I-V-L) characteristics of the polymers show turn-on voltages of 4.0 V approximately. Two fluoro groups were introduced on every vinylene units of m-SiP-PPV to give m-SiP-PPDFV in an attempt to increase the electron affinity of the parent polymer, and the devices show an increased color stability even with vinylene units. The color stability is attributed to the electron-withdrawing effect of the fluoro groups, which protect vinylene units from oxidation in PPV derivatives. We believe that fluoro groups can be introduced in vinylene units in order to attain excellent stability of PPV derivatives.

• BMB Reports
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• v.29 no.6
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• pp.493-499
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• 1996

The biochemical properties of purified D-hydruxyisovalerate dehydrogenase from Fusarium sambucinum was elucidated. D-Hydroxyisovalerate dehydrogenase produced solely D-hydroxyisovalerate from 2-ketoisovalerate. The isoelectric point of the purified enzyme was 7.0. The enzyme was highly specific with 2-ketoisovalerate ($K_{m}=0.188$ mM, $V_{max}=8.814$ mmol/min mg) and 2-keto-3-methyl-n-valerate ($K_{m}=0.4$ mM, $V_{max}=1.851$ mmol/min mg) for the reductive reaction. This was also seen by comparing D-hydroxyisovalerate ($K_{m}=1.667$ mM, $V_{max}=0.407$ mmol/min mg) and D-hydroxy-3-methyl-n-valerate ($K_{m}=6.7$ mM, $V_{max}=0.648$ mmol/min mg) for the oxidative reaction. Thiol blocking reagents, such as iodoacetamide, N-ethylmaleimide and p-chloromecuribenzoate inhibited about 80% of enzyme activity at 0.02 mM, 50 mM and 50 mM, respectively. The enzyme activity was also inhibited by the addition of 0.1 mM of various metal ions, such as $Fe^{2+}$ (67%), $Cu^{2+}$ (88%), $Zn^{2+}$ t (76%) and $Mg^{2+}$ (9%). The enzyme was stable over three months in 50 mM potassium phosphate buffer (pH 5~7) at $-80^{\circ}C$. However the purified enzyme lost 30% of its activity in the same buffer after 24 h at $4^{\circ}C$. The studies about thermal inactivation of D-hydroxyisovalerate dehydrogenase exhibit 209.2 kJ/M of activation enthalpy and 0.35 kJ/mol K of activation entropy.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.332-338
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• 1988

The density of heterotrophic bacterial population and heterotrophic activity were measured at monthly interval from March, 1986 to March, 1987 at four sites in the Sudong Stream, a tributary of North Han River. Total bacterial numbers and maximum uptake velocity ($V_{max}$) of glucose ranged as 0.8-$25.2\times 10^{5}$ cells/ml, 0.0006-24.39.$\mu$gC/1/hr, respectively. $V_{max}$ of glucose showed marked seasonal periodicity, with highest values in summer. But density of viable bacteria varied considerably, with no definite seasonal pattern. At the nucontaminated site which located in upstream, heterotrophic bacterial population and activities were relatively low, and small variations were observed downstream flowing except the site where animal originated sewage inputs occurred. And this large input of allochthonous materials and bacteria was an important factor for the stream condition.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.69-75
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• 2021

Recently, deep learning, which is the most used in the field of artificial intelligence, has a structure that is gradually becoming larger and more complex. As the deep learning model grows, a large amount of data is required to learn it, but there are cases in which it is difficult to integrate and learn the data because the data is distributed among several owners and security issues. In that situation we conducted parallel learning for each users that own data and then studied how to integrate it. For this, distributed learning was performed for each owner assuming the security situation as V-environment and H-environment, and the results of distributed learning were integrated using Average, Max, and AbsMax. As a result of applying this to the mnist-fashion data, it was confirmed that there was no significant difference from the results obtained by integrating the data in the V-environment in terms of accuracy. In the H-environment, although there was a difference, meaningful results were obtained.