• Applied Biological Chemistry
• /
• v.51 no.1
• /
• pp.88-91
• /
• 2008

숙성 중인 김치에서 생육과 산 생성이 우수한 유산균을 분리하여 API 50 CHL kit로 확인하고 16S rDNA의 염기 서열을 분석한 결과 Leuconostoc mesenteroides로 동정되어 Leuconostoc mesenteroides KC51로 명명하였다. 대두에 10배의 증류수를 가하여 제조한 두유에 KC51 균주를 접종하고 $30^{\circ}C$에서 정치 배양한 결과, 생균수는 접종 후 9시간까지 급격히 증가하였으며 그 이후 완만하게 증가하여 배양 12시간에는 $2.70{\times}10^9$ CFU/g까지 증가하였다. 적정산도는 배양 12시간에 0.35%까지 증가하였으며,pH 는 pH 4.52까지 감소하였다. 이때 유기산 농도는 젖산과 초산의 함량이 각각 0.56%와 0.10%로 분석 되었다. 두유 발효액에서 Leuconostoc mesenteroides의 증식에 의한 점도의 증가는 관찰되지 않았으며, 관능적으로도 신맛을 제외한 항목에서 두유와 유사하였다. 또한 $4^{\circ}C$에서 두유 발효액은 2주일의 저장기간 동안 pH, 적정산도와 생균수의 변화는 미미하였다.

• Journal of Applied Biological Chemistry
• /
• v.52 no.1
• /
• pp.33-37
• /
• 2009

A saccharified-rice was fermented using Leuconostoc(Ln.) mesenteroides KC51 strain in various dry matter (DM) contents (4%, 8%, and 12%) at $30^{\circ}C$ for 18 h. The changes of viable cell number, acid production and phytate degradation in saccharified-rice during fermentation were investigated. The viable cell population of Ln. mesenteroides KC51 was increased rapidly in proportion to DM contents during the 9 h of cultivation. The changes of pH and titratable acidity in saccharified-rice were dependent on DM contents. At high DM content (12%), the viable cell number of Ln. mesenteroides KC51 increased to 9.56 log CFU/g after 6 h of fermentation. The pH and titratable acidity reached to pH 3.38 and 0.93% after 18 h of fermentation, respectively. The phytate, known as an antinutrient factor, in saccharified-rice was degraded by Ln. mesenteroides KC51 cultivation. The decrease of phytate during fermentation approximately coincided with the increase of Ln. mesenteroides KC51 population observed in fermented saccharified-rice. Regardless of DM contents, the levels of phytate were reduced to around 50% of initial concentration.

• Journal of Aerospace System Engineering
• /
• v.7 no.2
• /
• pp.15-22
• /
• 2013

The conformity of propulsion system need to be evaluated thorough the flight test because it is an important part of the airplane to ensure the flight safety. In the small airplane development, the flight test according to KAS(Korean Airworthiness Standards) Part 23 is one of the ways to verify compliance in terms of satisfactory aircraft/engine/propeller integration. This thesis introduces means of verifying the compliance and test requirement of KAS Part 23 for the conformity of the propulsion system in small airplane. It also describes procedures and methods of propulsion system flight test through KC-100 airplane project.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2002.12a
• /
• pp.102-105
• /
• 2002

다기능 휠체어 시스템의 제어부인 80C196KC를 사용했으나, fuzzy 알고리즘을 적용하는데 있어서 여러 가지 문제점(속도, 연산, 외부장치 등) 때문에 구현1차는데 상당한 어려움이 있었다. 이를 해결하기 위해 20MIPS의 속도인 TMS320F240의 프로세서를 사용하였으며 이로 인해 발생하는 문제점을 거의 해소시켰고, 퍼지 알고리즘을 효율적으로 적용할 수 있었다. 본 시스템의 구성은 주제어기로 퍼지 제어 알고리즘을 사용하여 조이스틱을 제어시켰고, 2개 encoder를 입력을 받아 휠체어 회전수를 이용하여 제어시켰다. 휠체어 모터로는 BLDC(Brushless DC) 모터를 사용했으면, BLDC전용 드라이브단을 이용하여 모터를 구현시켰다. 그리고 3개의 초음파 센서를 부착하여 장애물 회피를 시도하였다. 초음파센서의 효율적인 사용을 위해 스텝 모터(Stepping Motor)와 마이크로 컨트롤러로 PIC을 사용하였다. 본 논문의 실험 결과에서는 이전의 제어기(80C196KC)보다 현저히 성능 면에서 향상되었고, 부수적인 외부장치 처리면에서도 상당한 차이를 볼 수 있었다

• Journal of Life Science
• /
• v.28 no.9
• /
• pp.1056-1061
• /
• 2018

This article reports an agar-degrading marine bacterium and characterizes its agarase. The agar-degrading marine bacterium, KC-1, was isolated from seawater on the shores of Sacheon, in Gyeongnam province, Korea, using Marine Broth 2216 agar medium. To identify the agar-degrading bacterium as Agarivorans sp. KC-1, phylogenetic analysis based on the 16S rRNA gene sequence was used. An extracellular agarase was prepared from a culture medium of Agarivorans sp. KC-1, and used for the characterization of enzyme. The relative activities at 20, 30, 40, 50, 60, and $70^{\circ}C$ were 65, 91, 96, 100, 77, and 35%, respectively. The relative activities at pH 5, 6, 7, and 8 were 93, 100, 87, and 82%, respectively. The extracellular agarase showed maximum activity (254 units/l) at pH 6.0 and $50^{\circ}C$ in 20 mM of Tris-HCl buffer. The agarase activity was maintained at 90% or more until 2 hr exposure at $20^{\circ}C$, $30^{\circ}C$ and $40^{\circ}C$, but it was found that the activity decreased sharply from $60^{\circ}C$. A zymogram analysis showed that Agarivorans sp. KC-1 produced 3 agar-degrading enzymes that had molecular weights of 130, 80, and 69 kDa. A thin layer chromatography analysis suggested that Agarivorans sp. KC-1 produced extracellular ${\beta}$-agarases as it hydrolyzed agarose to produce neoagarooligosaccharides, including neoagarohexaose (21.6%), neoagarotetraose (32.2%), and neoagarobiose (46.2%). These results suggest that Agarivorans sp. KC-1 and its thermotolerant ${\beta}$-agarase would be useful for the production of neoagarooligosaccharides that inhibit bacterial growth and delay starch degradation.

• Journal of fish pathology
• /
• v.29 no.1
• /
• pp.35-43
• /
• 2016

In comparison to the numbers of such studies of fish, few studies have been carried out on the immunity, physiology and ecology of abalone, while studies on abalone disease are also extremely rare. Moreover, mass mortality of cultured abalone due to pathogenic bacteria has not been reported in the southern coast of Korea. However, Vibrio-like bacteria have been isolated from dead abalone, which indicates that a review is required in order to determine the cause of abalone mortality. Use of an antimicrobial agent to minimize the damage caused by disease in abalone farms is common, but the therapeutic effects are insignificant. Demand for probiotics has increased, but research on the development of probiotics for use in abalone culture is very rare. Therefore, the present study isolated KC16-2 from fermented kimchi soup and investigated the characteristics of the isolate as a candidate probiotic bacterium in abalone. KC16-2 was identified as Bacillus amyloliquefaciens (B. amyloliquefaciens KC16-2) based on its biochemical properties and 16S rRNA gene sequence. B. amyloliquefaciens KC16-2 showed inhibitory effects against the growth of various vibrios in vitro, and kept the numbers constant until four days after inoculation in marine water at a temperature of $15{\sim}25^{\circ}C$, indicating the possible use of KC16-2 as a probiotic, except in the winter. The growth of KC16-2 was inhibited by bile salt, but the numbers increased over time suggesting the bacteria were still alive in the abalone's digestive tract. Abalone fed with a diet including KC16-2 for 12 weeks showed good growth, but showed no significant differences from the control group. However, the mortality of the abalone supplied the probiotic diet was reduced to half that of the control group in a challenge test with Vibrio tubiashii. Therefore, we suggest that B. amyloliquefaciens KC16-2 could be used as a probiotic bacterium for control of the mortality of abalone caused by opportunistic pathogenic vibrios.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.20 no.5
• /
• pp.510-521
• /
• 2008

In the study, experiments are performed in the interaction region combined with wave and current to investigate the characteristics of local scour around submarine pipelines. Wave generator and current generator are used for the experiments and two current directions were used; co-direction and counter direction to the wave. The local scour depths around the pipeline are obtained according to the various pipe diameters(D), wave periods(T), wave heights(H), and current velocities(V). The experiments show that the maximum equilibrium local scour depth increases with pipe diameter, wave period, wave height, and current velocity. Using the experimental results, the correlations of scour depth and parameters such as Shields parameter($\theta$), Froude number(Fr), period parameter, Keulegan-Carpenter number(KC), Ursell number($U_R$), modified Ursell number($U_{RP}$) and ratio of velocities($U_{c}/(U_{c}+U_{m})$) are analyzed. In the interaction region combined with waves and currents, Froude number and Shields parameter are found the main parameters to cause the local scour around the submarine pipelines and this means that current governs the scour within any limits of the currents.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.34 no.5
• /
• pp.169-175
• /
• 2022

Scour in a flow field affected by waves, such as river estuaries or shallow waters, is more difficult to predict than scour in a currents. The main issue in predicting the scour around circular files, such as undersea bridges, is the maximum scour depth and the point of occurrence. In the case of two or more adjacent circular piles, the location and depth of maximum scour according to the spacing between piles and the arrangement method show a lot of difference compared to the case of a single pile. In this paper, the KC number are calculated as dimensionless variables representing the strength of the flow. And the correlation between pile gap size and relative scour depth was analyzed.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.22 no.6
• /
• pp.405-414
• /
• 2010

In the study, experiments are performed in the mixing region combined wave and current to investigate the characteristics of local scour around a slender pile. Wave generator and current generator are used for the experiments and currents are co-directions with the waves. The local scour depths around the pipeline are obtained according to the various pipe diameters, wave periods, wave heights, and current velocities. The experiments show that the maximum equilibrium local scour depth increases with pipe diameter, wave period, wave height, and current velocity. Using the experimental results, the correlations of scour depth and parameters such as Shields parameter ($\theta$), Froude number (Fr), Keulegan-Carpenter number (KC), Ursell number ($U_R$), modified Ursell number ($U_{RP}$) and ratio of velocities ($U_c/U_c+U_m$) are analyzed. In the mixing region combined with waves and currents, The Froude number of single parameters is the main parameter to cause the local scour around a slender pile due to waves and current and this means that current governs the scour within any limits of the currents.

• Journal of the Korea Society for Simulation
• /
• v.26 no.2
• /
• pp.31-39
• /
• 2017

This paper analyses the effectiveness of Kill Chain (KC) and Korea Air and Missile Defense (KAMD), also known as the K2 systems, using monte carlo simulation. It is assumed that the K2 systems are consisted with unitary KC and multi-layered (upper-tier and lower-tier) KAMD. And each system has two or three arbitrary weapon systems and its combination makes 12 scenarios. Measures of effectiveness (MOE) of the K2 systems were defined as ratio of eliminated ballistic missiles from total threats. And total cost was calculated by number of weapon launched and its unit cost. MOE and total cost of the K2 systems were estimated using monte carlo simulation with a thousand iteration for each scenario. Cost-effectiveness analysis was performed and the best candidate was selected using fixed effectiveness approach. As a result, the performances of KC are prime factor that affects both effectiveness and total cost of the K2 systems. It is also, acquired proper level of lower-tier KAMD to achieve desired defense effectiveness. For future work, it needs to be performed cost-effectiveness analysis based on practical specification and life cycle cost of weapon systems.