• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.89-94
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• 2006

A compact microstrip band-selective filter for ultra-wideband(UWB) radio system is proposed. The filter combines the traditional short-circuited stub highpass filter and coupled resonator band-stop filter on both sides of the mitered 50-ohm microstrip line. To realize the pseudo-highpass filtering characteristic over UWB frequency band(3.1 GHz to 10.6 GHz), a distributed highpass filter scheme is adopted. Three coupled resonators are utilized to obtain the band stop function at the desired frequency band. By meandering the coupled resonators, there is $29\;\%$ size reduction in footprint compared to the traditional band-stop filter using L-shaped resonators. The measured results show that the filter has a wide passband of $146.7\;\%$(2.1 GHz to 10.15 GHz) with low insertion loss and the stop band of $10.04\;\%$(5.2 GHz to 5.75 GHz) for 3-dB bandwidth. The measured group delay is less than 0.7 ns within the passband except the rejection band.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.210-219
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• 1991

This study is to diagnose the drought tolerance of twenty broad-leaved tree species by the pressure-volume(P-V) curves. As for the diagnosis of drought tolerance, the valuable water relations parameters obtained from P-V curves are the osmotic potential at full turgor, ${\Psi}_0{^{sat}}$, osmotic potential at incipient plasmolysis, ${\Psi}_0{^{tlp}}$, maximum bulk modulus of elasticity, $E_{max}$, and relative water content at incipient plasmolysis, $RWC^{tlp}$. Also, the figures related to the diagnosis of drought tolerance are the free water content (FWC) versus leaf water potential(${\Psi}_L$), volume-averaged turgor pressure ($P_{vat}$) versus leaf water potential (${\Psi}_L$), and H$\ddot{o}$fler diagram. In this study, the relatively high drought tolerant species are Fraxinus rhynchophylla, Quercus acutissima, Quercus serrata, Quercus aliena, and Populus alba${\times}$glandulosa ; the relatively low drought tolerant species are Fraxinus mandshurica, Betula platyphylla var. japonica, Populus euramericana, Kalopanax pictum, Carpinus loxiflora, Carpinus cordata, Prunus sargentii, Prunus leveilleana, and Cornus controversa ; medium species are Quercus mongolica, Acer mono, Acer triflorum, Acer pseudo-sieboldianum, Ulmus davidiana, and Zelkova serrata.

• Journal of Korean Society of Forest Science
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• v.81 no.4
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• pp.325-336
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• 1992

The successional status and potential natural vegetation were examined in a mixed broadleaved-Abies forest located at Mt, Odae National Park. The examination was based on the subsequent process of generation replacement by understory saplings for the dominant canopy trees within 88 $5m{\times}50m$ belt transects. The transition matrix model, which was modified from mathematical theory of Markov chain, was employed to analyze the successional status of the study forest. The model suggests that the study forest is still seral, and it is considered to be more than 700 years away from the steady state or climax in terms of species composition. The simulations predict a remarkable decrease in the proportion of species composition of the present dominant Quercus mongolica and Tilia amurensi.s from current 28% and 13% to less than 3% and 5%, respectively, at the steady state. On the contrary, the proportions of Abies holophylla, Acer pseudo-sieboldianum, Carpinus cordata, and Pinus koraiensis will increase at the steady state. The ratio of mixture between deciduous and coniferous trees will be gradually changed from current 6.5 : 3.5 to 5.0 : 5.0 at equilibrium. Discussion for the problems of Quercus mongolica in successional status noted that the species behaved as a mid-successional dominant, not a climax species in the study forest. The hypothesis and sensitivity of the transition matrix model were also discussed to evaluate the applicability to the real situation. The overall results indicated that the present dynamics of the forest must reflect the seral state due to previous disturbance mainly by hyman related interference.

• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.330-336
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• 2015

Photocatalytic degradation of bisphenol A (BPA) in aqueous solution was investigated using $TiO_2$ nanoparticles (Degussa P25) in this study. After a 3 hr photocatalytic reaction (${\lambda}=365nm$ and $I=3mW\;cm^{-2}$, $[TiO_2]=2.0g\;L^{-1}$), 98% of BPA ($1.0{\times}10^{-5}M$) was degraded and 89% of the total organic carbon was removed. In addition, BPA degradation by photolytic, hydrolytic and adsorption reactions was found to be 2%, 5% and 13%, respectively. The reaction rate of BPA degradation by photocatalysis decreased with increasing concentration of methanol that is used as a hydroxyl radical scavenger. This indicates that the reaction between BPA and hydroxyl radical was the key mechanism of BPA degradation. The pseudo-first-order reaction rate constant for this reaction was determined to be $7.94{\times}10^{-4}min^{-1}$, and the time for 90% BPA removal was found to be 25 min. In addition, acute toxicity testing using Daphnia magna neonates (< 24 h old) was carried out to evaluate the reduction of BPA toxicity. Acute toxicity (48 hr) to D. magna was decreased from 2.93 TU (toxic unit) to non-toxic after photocatalytic degradation of BPA for 3 hr. This suggests that there was no formation of toxic degradation products from BPA photocatalysis.

• Korean Journal of Cognitive Science
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• v.26 no.1
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• pp.1-26
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• 2015

The purpose of this study was to examine whether the phonological information or the orthographic information plays a major role in visual word recognition. To do so, we used a non-word lexical decision task(LDT) in Experiment 1 and masked priming tasks in Experiement 2 and 3. The results of Experiment 1 showed that reaction times and the error rates were affected by the orthographic characteristics of the non-word stimuli such that orthographically similar non-words condition showed prolonged reaction times and higher error rates than control condition. In Experiment 2 and Experiment 3, the participants performed masked priming lexical decision tasks in two SOA conditions(60ms, 150ms). The results of the both experiments showed that the orthographically identical first syllable priming facilitated lexical decision of the target words while both of the pseudo-homophone priming and the phonologically identical first syllable priming did not. The dual route hypothesis(Coltheart et al, 2001), assuming that orthographic information rather than phonological information is the major source for the visual word recognition processes, fits well with the results of the current study.

• Journal of radiological science and technology
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• v.32 no.2
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• pp.141-146
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• 2009

This study analyzed decade-based statistic data which had been collected from the reports of annual radiographic pulmonary tuberculosis screening program initiated by the Korean National Tuberculosis Association (KNTA) for last 5 decades (from 1956 to 2005). We analyzed only the content of annual statistic report to preserve the characteristic of statistic data and the contents of original copy by focusing on the analysis of tuberculosis cases where age and sex were excluded. The results of the disease-based analysis on the tuberculosis cases from cumulative subjects of chest radiography (CXR) from 1956 to 2005 are summarized as follows. 1. The cumulative number of subjects who were examined under annual chest radiography over last 5 decades totaled 54,938,875 persons. 2. The cumulative number of pulmonary tuberculosis cases during same period totaled 958,251 persons (1.74%). 3. The cumulative number of subjects treated during same period totaled 465,082 persons (0.85%). 4. The cumulative number of mild pulmonary tuberculosis cases during same period totaled 229,615 persons (0.42%). 5. The cumulative number of moderate pulmonary tuberculosis cases during same period totaled 144,247 persons (0.26%). 6. The cumulative number of severe pulmonary tuberculosis cases during same period totaled 74,066 persons (0.13%). 7. The cumulative number of exudative pleurisy cases during same period totaled 17,154 persons (0.03%). 8. The cumulative number of subjects under monitoring during same period totaled 493,169 persons (0.90%). 9. The cumulative number of uncertain activity cases during same period totaled 78,214 persons (0.14%). 10. The cumulative number of pseudo-pulmonary tuberculosis cases during same period totaled 272,349 persons (0.50%).

• Korean Journal of Agricultural Science
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• v.6 no.2
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• pp.134-147
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• 1979

Mt. Kyeryong(828 meters in height) is located at $36^{\circ}18^{\prime}{\sim}36^{\circ}23^{\prime}$ N.L. and $127^{\circ}10^{\prime}{\sim}127^{\circ}17^{\prime}$ E.L., and also occupies three districts: Gongju-Gun, Nonsan-Gun, Daedeok-Gun. Authors surveyed the flora of the areas ten times from May to October, 1979. Variability of floras is rather high and dominant species are such as Pinus densiflora, Quercus mongolica, Quercus serrata, Quercus variabilis, Lindera erythrocarpa, Carpinus cordata, Acer pseudo-sieboldianum var. koreanum, Strax japonica, Sapium japonicum, Euonymus oxyphyllus, Sorbus alnifolia, Stephanandra incisa, Weigela subsessilis, Rhododendron mutcronulatum, Lespedeza bicolor, Sasa borealis, Celastrus orbiculatus, Arundinella hirta, Miscanthus sinensis var. purpurascans, and so on. There are 105 families, 355 genera, 679 species. According to the use of floras, they can be classified as follows; 69 familia and 287 species for edible source, 83 familia and 227 species of medicinal, 60 familia and 253 species for forage, 44 familia and 132 species for ornamental and 12 familia and 39 species for timber source.

• Journal of Korean Society of Forest Science
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• v.79 no.1
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• pp.33-41
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• 1990

The purpose of this study is to investigate the developmental process of plant community during the secondary succession through the analysis of floristic composition, life form etcectra in burned site, and the structure of forest stand before forest fire occurrence was estimated by the method of anatomical wood identification for dead trees in burned site, Cheisuk-bong in Mt. Chiri of Korea. Plant community before forest fire occurrence was estimated the high mountain conifer stand of the last successional stage to consist of Pinus koraiensis(75%), Abies koreana(15%) and Picea jezoensis(10%), and Betula costata was survived only one species after forest fire occurrence. The total number of plant species in the investigated area was 19 families and 23 species that was identified. The dominate species in burned site were Festuca ovina and Arrhenatherum elatius, Carex humilis, Ligularia fischeri etcectra in the investigated area flora. The life form of plant in burned site was the erect from 47.8%, the tufted from 30.4%, the branched and the prostrate from was both 8.7%, It was assumed that dominant species in the burned sites were Gramineae (Festuca ovina, Arrhenatherum elatius), Carex humilis ${\rightarrow}$Sorbus commixta, Rhododendron schrippenbachii, Sambucus williamsii var. coreana, Tripterygium regelii ${\rightarrow}$Acer pseudo-sieboldianum var. koreanum, Betula costata, Quercus mongolica${\rightarrow}$Pinaceae forest(Pinus koraiensis, Abies koreana, Picea jezoznsis).

• Journal of Korean Society of Forest Science
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• v.70 no.1
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• pp.17-27
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• 1985

Through the study of the physiognomical vegetation, the vertical distribution, the distribution of forest community and the flora of the woody plants on the south facing slope of Mt. Pal-Gong, the results obtained were summarized as follows. The forest of Pinus densiflora was dominant in the region of below 750m above the sea level, the mixed forest of conifer and broad-leaved trees in the region of 750m to 950m and the pure forest of deciduous broad-leaved trees in the region of above 950m. Pinus densiflora and Quercus mongolica were dominant for the upper-story trees, Acer pseudo-sieboldianum and Carpinus laxiflora for the mid-story trees, Lespedeza maximowiczii, Sasa purpurascens, Rhododendron mucronulatum and Rhododendron schlippenbachii for the under-story trees. Among seventeen forest communities, Cephalotaxus koreana, Populus davidiana and Alnus hirsuta var. sibirica were considered remarkable communities on the south facing slope of Mt. Pal-Gong. The woody plants growing on Mt. Pal-Gong are composed of 59 families, 7 subfamilies, 122 genera, 178 species, 29 varieties and 10 formae. Populus davidiana, Alnus hirsuta var. sibirica and Rubus phoenicolasius were collected newly in this study.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.10
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• pp.1142-1149
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• 2007

In this paper, the development of wideband MIMO channel sounder and a pilot measurement result is described for research on the multi antenna radio propagation characteristics considering urban environment at microwave frequencies. We developed $4{\times}4$ MIMO(BW:100 MHz) channel sounder using the high speed switching mechanism and periodic pseudo random binary signals method considering next generation mobile communication system. A pilot measurement campaign at the urban area of Bundang is presented for confirmation of system performance. From the analysis of measurement data, wideband path loss exponent of 3.7 and 8 GHz band is 1.79 and 1.76. Average RMS delay spread is 200 ns and 42 ns respectively. From the experiment results, operation of this measurement system is confirmed considering research for a coverage, SNR and channel capacity in urban environment at microwave frequencies.