• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.10-16
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• 2022

Since aviation systems are developed as the complex form of software a hardware, the necessity to apply to relevant guidelines is increasing. It is however uncommon that international development guidelines regarding electronic hardware are applied to current domestic aviation systems. In this paper, we compare and analyze DO-254 and ECSS-Q-ST-60-02C, electronic hardware development guidelines with the case of KASS (Korea Augmentation Satellite System) Performance Suitability, based on the project of SBAS (Satellite Based Augmentation System) development and construction.

• Journal of Plant Biology
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• v.28 no.2
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• pp.165-175
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• 1985

The natural forest vegetation of the Piagol, Mt. Chiri, was classified into five major communities, i.e. Quercus mongolica, Carpinus laxiflora, C. tschonoskii, Q. serrata and Fraxinus mandshurica community. C. tschonoskii, C. laxiflora and Q. mongolica characteristically were dominated in the range of 500∼700 m, 700∼900 m and 900∼1,400 m in altitude, respectively. Abies nephrolepis and Rhododendron schlippenbachii in the ridge of Nogodan-Nalnaribong, and F. mandshurica and Q. serrata in the Yongsuam ravine were found as the dominant species. The transition between C. tschonoskii and C. laxiflora communities was relatively wide. The boundary between F. mandshurica, in the conglomerated zone, and the other communities surrounding its community was fairly abrupt. In Q. mongolica community, the canopy was relatively opened and the oak young tree of undergrowth was fairly dense. In the community of C. laxiflora and C. tschonoskii, the species composed of their understory was rich while their coverage was lower than that of Q. mongolica community. Shannon's diversity index was decreased in order of C. tschonoskii, C. laxiflora and Q. mongolica community, while their Simpson's dominance index increased conversely. Judging by the DBH-class distribution showing the negative exponential curve, these communities were considered as the climax forest. In Polar Ordination used samples (quadrats), the vegetation of the Piagol was divided into five groups, which was coincided with five communities classified by Braun-Blanquet system. In the ordination, the first axis and the second axis may be considered soil conditions and thermal conditions, respectively. It seems that two different methods, phytosociological method in macro level and ordination techniques in micro level, are useful for the vegetation classification.

• Korean Journal of Environment and Ecology
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• v.24 no.5
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• pp.601-610
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• 2010

This study was carried out to classify vegetation structure of the southern and northern slopes in the Deogyusan National Park using TWINSPAN classification and DCCA ordination analysis. The vegetation on the southern slope was classified into Quercus mongolica community, Q. serrata community, Q. variabillis community, Pinus densiflora community, Carpinus laxiflora community, Cornus controversa community and Fraxinus mandshurica community. The vegetation on the northern slope was classified into Q. mongolica community, Q. serrata community, P. densiflora community, C. laxiflora community, Betula davurica community, C. controversa community, F. mandshurica community, B. costata community, Abies koreana community and Taxus cuspidata community. To find out important value in each slope, we took 103 districts on the southern slope and 137 districts on the northern slope. As the result, Q. mongolica was highest value in the southern and northern slopes, followed by P. densiflora, Q. serrata, Q. variabillis, Styrax obassia, Acer pseudosieboldianum in the southern slope, F. mandshurica, A. pseudosieboldianum, Q. serrata, C. laxiflora, C. controversa, C. cordata, Rhododendron schlippenbachii in the northern slope. Species distribution and ecological features had differences between the southern and northern slopes communities. As the result of DCCA ordination analysis, sea level and water availability had high correlation with community distribution. Besides, T-N, O.M., exchangeable Ca and pH did in the southern slope. And exchangeable Ca, pH also did in the northern slope.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2A
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• pp.177-183
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• 2009

In this paper, we propose an improved anti-collision algorithm. We have designed an anti-collision unit using this algorithm for the 18000-6 Type C Class 1 Generation 2 standard (Gen2). The Gen2 standard uses a Q-algorithm for incremental method on the Dynamic Slot-Aloha algorithm. It has basically enhanced performance over the Slot-Aloha algorithm. Unfortunately, there are several non-clarified parts: initial $Q_{fp}$ value, weighted C, and the ending point of the algorithm. If an incorrect value is selected, it causes degradation in performance. Thus we propose an improved anti-collision algorithm by clearly defining the vague parts of the existing algorithm. Simulation results showed an improved performance of up to 34.8% using an optimized value of C and the initial $Q_{fp}$ value. With the ending condition, performance is 34.7%. The anti-collision unit is designed using the Verilog HDL. The module was synthesized using Synopsys' Design Compiler and the TSMC $0.2{\mu}m$ standard cell library. The synthesized result yielded 3,847 gates, and was guaranteed under the proposed working frequency of 19.2MHz.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.662-675
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• 2022

This study was intended to investigate and analyze the current status of the plant community structure in order to provide basic data for the systematic conservation and management of the Buxus sinica area appearing on the ridgeline connecting the Gyeokjabong(Mt.) and Keungiljae, on Bogildo Island. In consideration of location characteristics such as density, topography, and direction of B. sinica appearing in the shrub layers, a total of 26 sites were set as the survey area for representative vegetation communities or areas with changes in topography. According to DCA and TWINSPAN, it was classified into 6 communities, namely Carpinus turczaninovii-Deciduous broad-leaved, C. turczaninovii, C. turczaninovii-B. sinica, C. turczaninovii-Evergreen broad-leaved, Q. acuta, and D. trifidus-Q. acuta. The community dominated by C. turczaninovii maintains the status quo for the present moment, however, Q. acuta will dominate the surrounding area in the long term, so Q. acuta has high succesion potential. In the case of the Q. acuta and D. trifidus-Q. acuta communities, Q. acuta, known as the climax species of warm-temperate forests, will maintain dominant status. In a case of B. sinica, the community dominated by C. turczaninovii will remain in good status due to the topographical conditions, but the community dominated by Q. acuta growth difficulties are expected due to the high coverage. In the relationship between environmental factors and vegetation distribution, analysis showed that only soil pH affect vegetation distribution. Furthermore, the soil acidity (pH) was 3.78-5.30, the electrical conductivity was 0.186-0.543 dS/m, and the organic matter content was 2.25-2.89%.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.566-573
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• 2014

Decay rate and nutrient dynamics during leaf litter decomposition of deciduous broad leaf Quercus mongolica and evergreen needle leaf Pinus densiflora were investigated for 69 months from December 2005 to September 2011 in Mt. Worak National Park as a part of National Long-Term Ecological Research Program in Korea. Percent remaining weight of Q. mongolica and P. densiflora leaf litter after 69 months elapsed was $35.4{\pm}2.3%$ and $16.1{\pm}1.3%$, respectively. Decomposition of P. densiflora leaf litter was significantly faster than that of Q. mongolica leaf litter. Decay constant (k) of Q. mongolica and P. densiflora leaf litter after 69 months elapsed was 5.97 and 10.50, respectively. Initial C/N and C/P ratio of Q. mongolica leaf litter was 43.1 and 543.9 respectively. After 69 months elapsed, C/N and C/P ratio of decomposing Q. mongolica leaf litter decreased to 8.7 and 141.2, respectively. Initial C/N and C/P ratio of P. densiflora leaf litter was 151.2 and 391.4, respectively. After 69 months elapsed, C/N and C/P ratio of decomposing P. densiflora leaf litter decreased to 22.9. and 136.5. respectively. Initial concentration of N, P, K, Ca and Mg in leaf litter was 9.30, 0.23, 2.36, 3.14, 1.11 mg/g in Q. mongolica, and 3.02, 0.09, 1.00, 3.84, 0.62 mg/g in P. densiflora, respectively. Initial concentration of N and P in Q. mongolica leaf litter was significantly higher than those in P. densiflora. After 69 months elapsed, remaining N, P, K, Ca and Mg in decomposing leaf litter were 73.8, 60.9, 17.2, 20.3, 35.1 % in Q. mongolica, and 69.5, 75.3, 12.3, 10.9, 10.8 % in P. densiflora, respectively.

• Journal of Life Science
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• v.25 no.8
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• pp.925-931
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• 2015

We performed a molecular marker-based analysis of quantitative trait loci (QTLs) for traits that determine the quality of the appearance of grains, using 120 doubled-haploid (DH) lines developed by another culture from the F1 cross between ‘Cheongcheong’ (Oryza sativa L. ssp. Indica) and ‘Nagdong’ (Oryza sativa L. ssp. Japonica). The traits studied included length, width, and thickness of the grains, as well as length-to-width ratio and 1,000-grain weight. The objective of this study was to determine the genetic control of these traits in order to formulate a strategy for improving the appearance of this hybrid. Within the DH population, five traits exhibited wide variation, with mean values occurring within the range of the two parents. Three QTLs were identified for grain length on chromosomes 2, 5, and 7. Three QTLs were mapped for grain width on chromosome 2: qGW2-1, qGW2-2, and qGW2-3. Six chromosomes were identified for the grain length-to-width ratio; four of these were on chromosome 2, whereas the other two were on chromosomes 7 and 12. One QTL influencing 1,000-grain weight was identified and located on chromosome 8. The results presented in the present study should facilitate rice-breeding, especially for improved hybrid-rice quality.

• Clean Technology
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• v.18 no.4
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• pp.366-372
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• 2012

Three acrylic copolymers containing tris(8-hydroxyquinoline) aluminum (AlQ3) pendant group (25 wt%), acrylateco-HEMA-$AlQ_3$ (25 wt%), were successfully synthesized by free radical polymerization from acrylates [methyl methacrylate (MMA), acrylonitrile (AN) or 2-hydroxyethyl methacrylate (HEMA)] with HEMA functionalized with AlQ3 pendant groups (HEMA-p-$AlQ_3$). The glass transition temperatures ($T_g$) of MMA-co-HEMA-p-$AlQ_3$ (copolymer 1), AN-co-HEMA-p-$AlQ_3$ (copolymer 2) and HEMA-co-HEMA-p-$AlQ_3$ (copolymer 3) were found to be 158, 150 and $126^{\circ}C$, respectively. They have good thermal stability: a very desirable feature for the stability of OLEDs. Their solubility, thermal properties, UV-visible absorption and photoluminescence behaviors were investigated. They were found to be soluble in various organic solvents such as tetrahydrofuran (THF), dimethylformamide (DMF), toluene and chloroform. It was also found that the UV-visible absorption and photoluminescence behaviors of these copolymers were similar to those of pristine $AlQ_3$. Green organic light-emitting diodes (OLEDs) have also been fabricated using these copolymers as light emission/electron transport components obtained easily by spin coating, and their current density voltage (J-V) curves were compared. The OLED device of the copolymer 3 had the lowest turn-on voltage of about 2 V compared to other copolymer types devices.

• Biomolecules & Therapeutics
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• v.18 no.1
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• pp.99-105
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• 2010

The purpose of this study was to evaluate relative bioavailability of the coenzyme Q10 (CoQ10) in emulsion and three liposome formulations after a single oral administration (60 mg/kg) into rats. Emulsion formulation of CoQ10 was prepared by conventional method using Phospholipon 85G as an emulsifier, and three liposome formulations (neutral, anionic, and cationic) of CoQ10 were prepared by traditional lipid film hydration technique using Phospholipon 85G, cholesterol, and charge carrier lipids (1,2-dioleoyl-3-trimethylammonium-propane chloride salt for cationic liposome and 1,2-dimyristoyl-sn-glycero-3-phosphate monosodium salt for anionic liposome). Mean particle size of all CoQ10-loaded liposome was less than a micron, and size distribution of the liposome population was homogeneous. Bioavailability of CoQ10 in emulsion was 1.5 to 2.6-fold greater than liposome formulations in terms of $AUC_{0-24\;h}$. $T_{max}$ was 3 h when administered as emulsion while it was greater than 6 h in liposome formulations. Notably, it was approximately 8 h in cationic liposome. $C_{max}$ was highest in emulsion and was significantly decreased when administered as liposome. Charged liposome showed even lower $C_{max}$ than neutral liposome, especially in cationic liposome. In conclusion, therefore, it is suggested that clinicians and patients consider bioavailability issue a primary concern when choosing a CoQ10 product, especially when very high plasma level is required such as in the treatment of heart failure and Parkinson's disease.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2116-2118
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• 2000

In the technique of Q-switching, very fast electronically controlled optical shutters can be made by using the electro-optic effect in crystals or liquids. The driver for the Pockels cell must be a high-speed, high-voltage switch which also must deliver a sizeable current. Common switching techniques include the use of vacuum tubes, cold cathode tubes, thyratrons, SCRs, and avalanche transistors. Semiconductor devices such as SCRs, avalanche transistors, and MOSFETs have been successfully employed to drive Pockels cell Q-switch. In this study, a simple driver for the Pockels cell Q-switch was developed by using SCRs, pulse transformer and TTL ICs. The Pockels cell Q-switch which was operated by this driver was employed in pulsed Nd:YAG laser system to investigate the operating characteristics of this Q-switch. And we have investigated the output characteristics of this Q-switch as a function of the Q-switch delay time to Xe flashlamp current on.