• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4095-4100
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• 2011

In this paper, a log periodic bow-tie dipole array (LPBDA) antenna for UWB communications is investigated. Bow-tie shaped dipole elements are used instead of general dipole elements for LPDA antennas and the input reflection coefficient and realized gain characteristics of the LPBDA as a function of a flare angle are analyzed. It turns out that as the flare angle of the bow-tie dipole elements is increased, the lowest operating frequency is shifted toward lower frequency and the operating frequency band is increased, but the average gain is decreased. However, the gain variation of the LPBDA is much decreased and the front-back ratio is improved compared to the LPDA. Standard LPDA and LPBDA with a flare angle of 13 degrees are fabricated on an FR4 substrate with a dielectric constant of 4.4 and a thickness of 1.6 mm. Measured gain for the LPDA ranges from 4 to 6.5 dBi at 3.1 to 10.6 GHz band, while that for the LPBDA is in the range of 4.2 to 5 dBi.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.4
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• pp.195-200
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• 2006

The conventional discrete circuit for ABS/TCS system was examined and the problems of the system were analyzed by computer simulation. In order to improve the performance of ABS/TCS system, interface IC which has error compensation, comparator and under voltage lock-out circuit was designed and their electrical characteristics were investigated. The voltage regulator was included to compensate the temperature variation in the temperature range from $-20^{\circ}C$ to $120^{\circ}C$ for automobile environment. ABS and brake signal were separated using the duty factor of same frequency or different frequencies. UVLO(Under Voltage Lock-Out) circuit and constant current circuit were applied for the elimination of noise, and protection circuit was applied to cut the excess current off. Layout for IC fabrication was designed to enhance the electrical performance of ABS/TCS system. Layout was consisted of 11 masks, arrayed effectively 8 pads to reduce the current loss. We can see that the result of layout simulation was better than the result of bread board.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.489-495
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• 2010

Hyperspectral imaging obtains information with a wider wavelength range a large number of bands. However, a high correlation between each band, computation cost, and noise causes inaccurate results in cases of no pre-processing. The noises of band extraction and elimination positively necessary in hyperspectral imaging. Since the previous studies have used a characteristic the whole image, a local characteristic of the image is considered for the noise band extraction. In this study, the Quadtree, which is a data structure algorithm. and the fractal dimension are adopted for noise band extraction in Hyperion images. The fractal dimensions of the segments divided by the Quadtree structure are calculated, and variation is used. We focused on the extraction of random noise bands in Hyperion images and compared them with the reference data made by visual decisions. The proposed algorithm extracts the most bands, including random noises. It is possible to eliminate more than 30 noise bands, regardless of images.

• Animal Systematics, Evolution and Diversity
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• v.8 no.2
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• pp.231-242
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• 1992

Samples of two species of genus Ratts(black rat, Rattus rasttus Linnaeus; common rat, Rattus norvegicus Berkenhaut) in Korea were trapped and their 31 morphometric charcters were analyzed statistically in order to determine the range of geographic variation within each species and the interspecific differences. In addition, chromosomal G-bands and C-bands were compared and the fragment patterns of mtDNA resulted from the digestion with restriction enzymes were also analyzed. Samples of black rats from six localities in Korea were similar with one another in their morphometric characters: in head and body length, length of tail vertebrae, conventional karyotype and C-bands, they are comparable to Rattus rattus tanezumi in Japan. Specimens of common rats from seven localities in Korea were similar with one another in their morphometric characters: in conventional karyotype, they are comparable to Rattus norvegicus caraco in eastern Asia. Common rats differ from black rats in their morphometric characteris, chromosomal karyotypes and mtDNA. It is confirmed that correct species name of black rat in Korea is Rattus rattus tanezumi Tempminck: species name of common rat in Korea is Rattus norvegicus caraco Pallas: the common rat is a species, which is distinct from the black rat.

• The Research Journal of the Costume Culture
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• v.29 no.4
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• pp.572-584
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• 2021

The emergence of environmental and social issues has led to global discussions for the realization of sustainable development. The purpose of this study is to propose a method of sustainable fashion design using waste Hanbok, focusing on men's Hanbok with cultural values. The study utilizes literature research and fashion design development. From the literature study, reform was judged to be a higher concept encompassing reduction, recycling, and upcycling. Reduction is a design method through removal, and recycling design transforms from its original form into a completely different product. Upcycling design focuses on improvement and change in functionality. Accordingly, nine redesigns using men's Hanbok were developed from which three were produced. Consequently, the reduction design demonstrated a small range of variation without changing the item, and cultural sustainability was confirmed through the design that removed the components and recombined the Hanbok. Second, recycling redesign can be reconstituted into a different item. Third, upcycling enables various designs through module assembly, which prolongs the lifespan of the product and confirms its value as a raw material for waste Hanbok. This study is meaningful in realizing sustainable fashion and suggesting practical measures for the sustainability of Korean traditional culture and creative fashion design planning.

• Journal of IKEEE
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• v.27 no.4
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• pp.567-572
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• 2023

In this paper, the breakdown voltage of Pi-LDMOS (Partial isolation lateral double diffused metal oxide semiconductor) was analyzed by simulation. Breakdown voltage variation is investigated under various settings of Parial buied oxide(P-BOX) parameters(length, thickness, location) and their mechanism is specified. In addition, the change in on-resistance in the breakdown voltage and trade-off relationship was analyzed according to the change in the P-BOX parameter, and the Figure-of-merit(FOM) was calculated and compared. In proposed structure, Lbox=5 ㎛, tbox=2 ㎛, and Lbc=2 ㎛ showed the highest breakdown voltage of 138V, and Lbox=5 ㎛, tbox=1.6 ㎛, and Lbc=2 ㎛ showed the highest FOM. Compared to conventional LDMOS, the breakdown voltage is 123% and FOM is 3.89 times improved. Therefore, Pi-LDMOS has a high breakdown voltage and FOM, which can contribute to the improvement of the stable operating range of the Power IC.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.449-455
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• 1997

The anisotropic etching behavior of single crystal silicon were studied in aqueous KOH solution. N-type (100) oriented single crystal silicon wafers were used for the study, and the $SiO_2$ layer, whose etching rate is known to be much slower than that of silicon in the KOH solution, was used as a mask for the silicon etching. The silicon etching rate and the etching properties are shown to be a function of etchant temperature uniformity, circulation speed, and circulation direction of the etchant as well as the etchant concentration and the temperature. The etching rate is increased as the temperature is increased from $10\mu \textrm{m}/hr$ to $250\mu \textrm{m}/hr$ in the range of $50^{\circ}C~105^{\circ}C$. Hillock density and height is observed to be correlated with the etchant concentration and the etch temperature. The variation of the hillock density was explained by the ratio between the etching rate of (100) orientation and that of (111) orientation.

• 한국해양학회지
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• v.23 no.4
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• pp.184-193
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• 1989

To study the pelagic fish egg community in the mid-east coastal waters of the Yellow Sea, pelagic eggs were sampled with Bongo net at 13 stations from Chonsu Bay to Keum Estuary from July, 1985 to June, 1986. Nineteen taxa of pelagic eggs were collected. Among them, 7 taxa were identified to the species level, and 2 taxa to the family level. Engraulis japonica was the most abundant species with 89.5% of the total eggs; Sillago japonica was 2.5%; Clupanodon punctatus, 2.4%; Herklotsichthys zunasi, 1.7%; Callionymidae spp., 1.6%. These 5 taxa occupied 97.7% of the total eggs. Pelagic eggs occurred from April to October. In June and July, their abundances were high, but the species diversities were low as E. japonica eggs were predominant. The range of spawning temperature for each taxa were estimated from the occurence pattern of the pelagic eggs.

• Journal of the Korean Society for Heat Treatment
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• v.21 no.5
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• pp.244-250
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• 2008

This study has investigated the surface phase change, hardness variation, surface precipitates, nitrogen content and corrosion resistance in STS 431 (17Cr-2Ni-0.2C-0.01Nb) martensitic stainless steel after high temperature gas nitriding (HTGN) treatment at the temperature range between $1050^{\circ}C$ and $1150^{\circ}C$. The HTGN-treated surface layer appeared $Cr_2N$ of rod type, carbo-nitride of round type and fine precipitates in the austenite matrix. On the other hand the interior region where the nitrogen was not permeated, exhibited martensite phase. The surface hardness showed 250~590 HV, depending on the HTGN treatment conditions, while the interior martensitic phase represented 520 HV. The permeation depth of nitrogen increased with increasing the HTGN-treated temperature. The nitrogen concentration of the surface layer appeared approximately ~0.17% at $1100^{\circ}C$. On comparing the corrosion resistance between solution-annealed and HTGN-treated steels, the corrosion resistance of HTGN-treated steel was superior to that of solution-annealed specimens.

• Ocean and Polar Research
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• v.28 no.4
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• pp.395-405
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• 2006

We measured the fugacity of $CO_2$ $(fCO_2)$, temperature, salinity, nutrients and chlorophyll a in the surface water of the western North Pacific $(4^{\circ}30'{\sim}33^{\circ}10'N,\;144^{\circ}20'{\sim}127^{\circ}35'E)$ in September 2002. There were zonally several major currents which have characteristics of specific temperature and salinity (NECC, North Equatorial Counter Current; NEC, North Equatorial Current; Kuroshio etc.). Surface $fCO_2$ distribution was clearly distinguished into two groups, tropical and subtropical areas of which boundary was $20^{\circ}N$. In the tropical Int surface $fCO_2$ was mainly controlled by temperature, while in the subtropical area, surface $fCO_2$ was dependent on total inorganic carbon contents. Air-sea $CO_2$ flux showed a large spatial variation, with a range of $-0.69{\sim}0.79 mmole\;m^{-2}day^{-1}$. In the area of AE (Anticyclonic Eddy), SM(Southern Mixed region) and NM (Northern Mixed region), the ocean acted as a weak source of $CO_2$ $(0.6{\sim}0.79 mmole\; m^{-2}day^{-1})$. In NECC, NEC, Kuroshio and ECS (East China Sea), however, the fluxes were estimated to be $-0.3mmole\; m^{-2}day^{-1})$ for the first three regions and $-1.2mmole\; m^{-2}day^{-1})$ for ECS respectively, indicating that these areas acted as sinks of $CO_2$. The average air-sea flux in the entire study area was $0.15mmole\;m^{-2}day^{-1})$, implying that the western North Pacific was a weak source of $CO_2$ during the study period.