• Korean Journal of Environmental Biology
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• v.20 no.1
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• pp.25-34
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• 2002

The halophytes were investigated on Gyeonggi Bay from Aug. 1999 to Oct. 2001. The survey was conducted at 38 areas including natural salt marshes, dunes, abandoned salt farms and bank areas. During this study 46 species of halophytes were collected in the areas. Among the halophytes the following 7 species were found at natural salt marshes only; Triglochin maritimum L, Carex scabrifolia Steud., Salicornia herbacea L., Suaedu australis (R. Br.) Moq., S. martima Dum., S. japonica Makino, S. malacosperma Hara, on the other hand 8 species at dunes only; Glehnia littoralis Fr. Schm., Cnidium japonicum Miq., Messerschmidia sibirica L., Ixeris repens A. Gray, Corispermum stauntonii Miq., Vitex rotundifolia L. fil., Ischaemum anthephoroides Miq., Carex kobomugi Ohwi. The distributions of halophytes in each regions are as the followings : Isl. Gyodong-do 21 species, Isl. Seokmo-do 10 species, Isl. Ganghwa-do 28 species, Isl. Jangbong-do 16 species, Isl. Sin & Si-do 10 species, Isl. Daemuui-do 23 species, Isl. Deokjeok-do 23 species, Isl. Ijak-do 10 species, Isl. Yeongheung-do 29 species, Soyra 25 species, Isl. Daebu-do 15 species, Ssangsong-ri 6 species, Hogok-ri 16 species, Maehyang-ri 10 species.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1112-1113
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• 2006

The perovskite- type oxide $(ABO_3)$ containing transition metals on the B-site show mixed (electronic/ionic) conductivity. These mixed-conductivity oxides are promising materials for oxygen permeating membranes. The main objective of this research work is to synthesize and characterization ceramic powders of the Sr-Co-Fe-O system for methane conversion using membrane reactor. SCFO powders were synthesized from the route was based on the complex method of combination of acid EDTA and citrate and shown be available by control efficient of synthesis to performed $SrCo_{0.8}Fe_{0.2}O_{3-\delta$, moreover, it presented easy implementation, reproducibility and operation. Powder ceramic was characterized by XRD, microscopic optic, SEM and TG-DTA.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1121-1126
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• 2017

Various studies such as INS(: Inertial Navigation System) are conducting to estimate the position of UAV, because the GPS information of UAV is at risk like the GPS jamming. The position estimation using DoA and RTT are used to apply many radar systems, and that process can be applied in datalink of UAV. The general monopulse feed in UAV datalink is Multi-horn, because of the wide BW(: Band Width) and frequency range. And it needs wide SNR range of tracking because of the limited transmit power of airborne unit. The estimation error of position increase at low SNR, and the DoA is valid in only 3dB beam width but high SNR causes false of mainlobe detection because of large sidelobe. In this paper, We propose the method to achieve higher accuracy of DoA estimation on low SNR and review some idea that able to detect mainlobe.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.65-73
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• 2008

Security layer of the Cdma2000 1x EV-DO is currently completing standard (C.S0024-A v2.0). Accordingly, a hardware security devices, that allows to implementation requirement of the security layer described in standard document, is required to apply security function about data transferred between AT and AN of then Cdma2000 1x EV-DO environment. This paper represents design of hardware device providing EV-DO security with simulation of the security layer protocol via the FPGA platform. The SHA-1 hash algorithm for certification and service of packet data, and the AES, SEED, ARIA algorithms for data encryption are equip in this device. And paper represents implementation of hardware that applies optionally certification and encryption function after executing key-switch using key-switching algorithm.

• Journal of Platform Technology
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• v.8 no.4
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• pp.47-58
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• 2020

DO-330 Software Tool Qualification Considerations is a guideline for development of tools used to develop/verify software and hardware installed on aircraft. And among several processes, the verification process is very crucial as it occupies a large proportion for DO-330. Especially, in order to qualify tool with high safety level, test objectives must be performed with independence, accordingly, more time, cost, and manpower are required than other objectives. In addition, even if the test cases or test procedures are well defined, the higher the complexity of the test the higher probability of human error occurs. In this paper, we propose Script-based Test Automation Agent software structure for efficient DO-330 verification process of A661UAGEN tool developed by Hanwha Systems. Compared to the test performed manually by the test engineer, testing time of the Script-based Test Automation Agent is reduced by 87.5% and testing productivity is increased by 43.75%.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.679-686
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• 2022

In this paper, we implemented an algae removal device that recognizes and removes algae existing in water using Raspberry Pi camera and DO (Dissolved Oxygen) sensor. The Raspberry Pi board recognizes the color of green algae by converting the RGB values obtained from the camera into HSV. Through this, the location of the algae is identified and when the amount of dissolved oxygen's decrease at the location is more than the reference value using the DO sensor, the algae removal device is driven to spray the algae removal solution. Raspberry Pi's camera uses OpenCV, and the motor movement is controlled according to the output value of the DO sensor and the result of the camera's green algae recognition. Algae recognition and spraying of algae removal solution were implemented through Arduino and Raspberry Pi, and the feasibility of the proposed portable algae removal device was verified through experiments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.626-633
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• 2023

Vibrio spp. are aquatic bacteria that are ubiquitous in warm estuarine and marine environments. Especially, V. vulnificus and V. cholerae are currently known to cause potentially fatal infections in humans. This study investigated the distribution and antibiotic resistance of V. vulnificus and V. cholerae isolated from coastal areas of Gyeongsangnam-do in 2022. A total of 252 samples of water, shellfish and coastal sediment were collected from 7 locations along the coast, and 124 samples of fishery products were collected from markets. Among the 252 samples, forty-four V. vulnificus (11.7%) and fourteen V. cholerae non-O1/non-O139 (3.7%), none of which carried the ctx gene, were isolated. Out of the 124 samples, 6 (4.8%) tested positive for V. vulnificus and V. cholerae was not detected. The isolation rates of V. vulnificus and V. cholerae showed a significant correlation with environmental factors such as seawater temperature and salinity. In an antibiotic resistance test, V. vulnificus was susceptible to amikacin, gentamicin, imipenem trimethoprim/sulfamethoxazole, and ciprofloxacin, but resistant to cefoxitin (100.0%), followed by tetracycline (9.1%). Multidrug resistance was also observed. Continuous monitoring of Vibrio pathogens with water temperature and salinity is expected to help reduce the outbreaks, and rational use of antibiotic agents is needed to prevent the accession of antibiotic-resistant microorganisms in aquatic ecosystems.

• The Korean Journal of Mycology
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• v.44 no.1
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• pp.23-30
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• 2016

This study was conducted for comparison of ingredients, phytochemical compounds and antioxidant activity of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do, and Jeolla-do. Three contents of Wofiporia extensa were analyzed as oxygen (46~48%), carbon (38~39%), hydrogen (6.05~6.1%) and nitrogen (0.17~0.21%). The mineral contents of 50% ethanol Wofiporia extensa extracts were measured as sulfur (S) 145~149 ppm, Magnesium (Mg) 69~72 ppm, phosphorus (P) 122~154 ppm and calcium (Ca) 210.61~509.98 ppm. Wofiporia extensa from Gyeongsang-do (509.98 ppm) contained a significantly higher quantity of Ca than that from Gangwon-do (210.62 ppm) and Jeolla-do (223.88 ppm). In the gas chromatograph-mass spectrometry (GC-MS) analysis, oleic acid was identified in three 50% ethanol Wofiporia extensa extracts. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay for antioxidant activity, the $IC_{50}$ values of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do and Jeolla-do were calculated as 2.966 mg/mL, 23.03 mg/mL, and 4.16 mg/mL and 3.521 mg/mL, 12.17 mg/mL, and 7.40 mg/mL. In the ferric reducing antioxidant power (FRAP) assay, the $IC_{50}$ values of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do, Jeolla-do were 6.585 mg/mL, 19.06 mg/mL, and 18.97 mg/mL, respectively. In summary, Wofiporia extensa cultured in Gangwon-do had stronger antioxidant activity and higher concentration of oleic acid than that of Geyongsang-do and Jeolla-do. However, Wofiporia extensa cultured in Geyongsang-do contained a much higher concentration of Ca than that of Gangwon-do and Jeolla-do.

• ALGAE
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• v.19 no.3
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• pp.235-245
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• 2004

A study on seasonal characteristics of phytoplankton dynamics and environmental factors was carried out at four stations including Mara-do and U-do located in the western and eastern coast of Jeju Island in southern Korea from April 2003 to March 2004. Out of 101 phytoplankton species identified, 84 belong to Bacillariophyceae, 9 Dinophyceae, 6 phytoflagellates and 2 coccolithophorids, and the highest value of species diversity was observed in April. Phytoplankton was more abundant at the western coast than at the eastern coast from March to September and its highest abundance was 49.24 ${\times}$ 10$^3$ cells L$^{-1}$ at Mara-do in July. The pennate diatoms were more abundant at the western coast than at the eastern coast with the highest abundance of 38.75 ${\times}$ 10$^3$ cells L$^{-1}$ at Mara-do in July, and during this period Nitzschia longissima contributed 68.5% of the total phytoplankton abundance. Naviculaceae was more abundant at Gosan (western coast) in November when Stauroneis membranacea represented 80.1% of the abundance. Leptocylindrus dances contributed 49.4% of the abundance at U-do in November. Dinophyceae was more abundant at U-do in August. Water temperature and pH fluctuated from 11.7${^{\circ}C}$ to 27.1${^{\circ}C}$ and from 7.31 to 8.70, respectively. Water temperature of Mara-do was about 1-2${^{\circ}C}$ higher than the other stations. Salinity varied from 30.4 to 35.0 psu with the minimum in rainy season and the maximum at the end of winter. The concentration of NH$_4$-N, NO$_3$-N, NO$_2$-N, PO$_4$-P and SiO$_2$-Si ranged 0.07-6.79, 1.0-62.0, 1.0-8.0, 1.0-7.0 and 7.0-191.0 $\mu$g-at L$^{-1}$, respectively. Chlorophyll a concentrations varied from 0.10 to 1.17 $\mu$g L$^{-1}$. NH$_4$-N concentrations were high at U-do from May to December, and at Mara-do from January to February. The high concentrations of NO$_3$-N were found at Mara-do from June to September and at U-do from January to May. The effects of various physicochemical parameters on the seasonal distribution and succession of phytoplankton population suggest that there is a classical pattern of phytoplankton dynamics in Jeju coastal waters.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1690-1698
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• 2006

In order to investigate the effect of dissolved oxygen (DO) level on AVM $B_{1a}$ production by a high yielding mutant of Streptomyces avermitilis, five sets of bioreactor cultures were performed under variously controlled DO levels. Using an online computer control system, the agitation speed and aeration rate were automatically controlled in an adaptive manner, responding timely to the oxygen requirement of the producer microorganism. In the two cultures of DO limitation, the onset of AVM $B_{1a}$ biosynthesis was observed to casually coincide with the fermentation time when oxygen-limited conditions were overcome by the producing microorganism. In contrast, this phenomenon did not occur in the parallel fermentations with DO levels controlled at around 30% and 40% throughout the entire fermentation period, showing an almost growth-associated mode of AVM $B_{1a}$ production: AVM $B_{1a}$ biosynthesis under the environments of high DO levels started much earlier than the corresponding oxygen-limited cultures, leading to a significant enhancement of AVM $B_{1a}$ production during the exponential stage. Consequently, approximately 6-fold and 9-fold increases in the final AVM $B_{1a}$ production were obtained in 30% and 40% DO-controlled fermentations, respectively, especially when compared with the culture of severe DO limitation (the culture with 0% DO level during the exponential phase). The production yield ($Y_{p/x}$), volumetric production rate (Qp), and specific production rate (${\bar{q}}_p$) of the 40% DO-controlled culture were observed to be 14%, 15%, and 15% higher, respectively, than those of the parallel cultures that were performed under an excessive agitation speed (350 rpm) and aeration rate (1 vvm) to maintain sufficiently high DO levels throughout the entire fermentation period. These results suggest that high shear damage of the high-yielding strain due to an excessive agitation speed is the primary reason for the reduction of the AVM $B_{1a}$ biosynthetic capability of the producer. As for the cell growth, exponential growth patterns during the initial 3 days were observed in the fermentations of sufficient DO levels, whereas almost linear patterns of cell growth were observed in the other two cultures of DO limitation during the identical period, resulting in apparently lower amounts of DCW. These results led us to conclude that maintenance of optimum DO levels, but not too high to cause potential shear damage on the producer, was crucial not only for the cell growth, but also for the enhanced production of AVM $B_{1a}$ by the filamentous mycelial cells of Streptomyces avermitilis.