• Korean Journal of Food Science and Technology
• /
• v.35 no.3
• /
• pp.442-446
• /
• 2003

Over two hundred fungal strains from Korean soil were tested for the production of cholesterol-lowering agent, lovastatin. Each fungal strain was cultivated in the rapeseedmeal production medium (RPM). After growing for 7 days, the presence of lovastatin in the culture was examined by TLC analysis and HPLC. Nine different fungal strains were determined to produce detectable amounts of lovastatin, among which one fungal strain isolated from barnyard manure of Kanghwa island produced 25.58 mg/L of lovastatin in the production medium. The morphological observation combined with the determination of 18S-rRNA sequence suggested that the selected strain belongs to a member of Aspergillus sp..

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.2
• /
• pp.335-342
• /
• 2020

ESS(Environmental Stress Screening) is an important production process to remove 'latent defects' introduced in the production of products. Recently, ESS is included in QAR(Quality Assurance Report) as an essential quality assurance requirement for products in the defense business. However, depending on the author of the QAR or the classification of the weapon system, it is often identified that the content and form are different or important elements are omitted. Therefore, this paper proposes a MIL-HDBK-344A based quantitative ESS requirement standard to secure the consistency and completeness of QAR. and to make easier to calculate PE(Precipitation Efficiency), which is an indicator for identifying the latent defects elimination effect.

• Asia Pacific Journal of Business Review
• /
• v.1 no.2
• /
• pp.17-35
• /
• 2017

This research is a case study that focuses on how conglomerate illegality and corresponding penalty affects corporate performance and strategy. The research aims to provide base information for policy-makers as well as the general public about the corporate environment. The analysis results can be summarized as follows. First, profitability is represented as an M-curve. Profitability falls from indictment to the final pronouncement of the corporate head and increases upon his or her return. The result suggests that the absence of a corporate head could result in low profitability as the firm is exposed to owner risk. Secondly, significant effects on investment were not found. Investment showed a continuous increase from indictment to final judgment. This could have resulted from investment decisions made prior to the indictment, which are generally long-term. Meanwhile, the rate at which investments rose for core subsidiaries were lower, which makes it reasonable to suspect dwindling executive capacity due to the absence of a corporate head. Thirdly, employment showed a slight increase, but the rate was found to be greater during the periods following the final judgment. From a political perspective, this increase can be inferred from a give-and-take tradeoff between corporate employment and the pardon of the corporate head.

• Journal of the Society of Naval Architects of Korea
• /
• v.48 no.1
• /
• pp.8-14
• /
• 2011

RIB(Rigid Inflatable Boat) is widely used for coastal transportation in the commercial use and for ISR(Intelligence, Surveillance, Reconnaissance) in the military use. Since RIB is around 10 meters in length and over 30 knots in speed, its motion characteristics in waves is quite different from a large scale ship. When it turns, large roll occurs and heeling direction is opposite to the large ship's case. Currently, many countries are developing USV(Unmanned Surface Vehicle) of which type is RIB. In order to develop high performance autopilot and way point controller, it is very important to identify RIB's motion characteristics. In this paper, sea trial test results of a 7-meter RIB such as speed, turning, zig-zag, and way point control tests were represented and its resistance and propulsion model was identified by using sea trial data and Savitsky's formula. In addition, the state space model which will be used in the identification of the four-degree-of-freedom dynamics in the next step was formulated and the identification procedure was proposed.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.4
• /
• pp.617-624
• /
• 2020

Due to the rapid development of science technology and the main characteristics of the defense industry, such as long development period, design complexity, high possibility of discontinuing parts due to long life cycle, and small quantity production, it can cause increasing of the inflow possibility of counterfeit electronic parts and deteriorating the reliability of weapons systems. This paper presents the specific criteria for the identification of electronic parts to be verified for mass produced weapons systems after the development is completed, and the identification and verification methods for the inflow of counterfeit electronic components.

• Journal of Convergence for Information Technology
• /
• v.9 no.11
• /
• pp.118-124
• /
• 2019

As Unmanned Aerial Vehicles technology has been widespread, various types of unmanned aircraft and mission equipment have been developed in line with mission diversification. Especially in Korea, small unmanned aerial vehicles have been actively developed. In addition, flight control system and mission equipment interface system for effective control of small unmanned aerial vehicles, efficient communication system configuration and operation for transmission to ground operated systems by processing data are required. This paper addresses efficient system structure and operation of communication equipment for missions and control of small unmanned aerial vehicles.

• Journal of Aerospace System Engineering
• /
• v.15 no.6
• /
• pp.42-49
• /
• 2021

To develop a high-resolution electro-optical/infrared (EO/IR) payload to be mounted on a high-speed and performance fighter aircraft in an external POD for acquiring daytime and nighttime image information on tactical targets, simulations, including flight environments and maneuvers, should be performed. Such simulations are pertinent to predicting the performance of several variables, such as aerodynamic force and inertia load acting on the payload. This paper describes the development of a flight data acquisition and analysis system based on flight simulation software (SW) for mission simulation of super-maneuverability fighter equipped with EO/IR payload. The effectiveness of the system is verified through comparison with actual flight data. The proposed flight data acquisition and analysis system based on FlightGear can be used as an M&S tool for system performance analysis in the development of the EO/IR payload.

• Journal of Astronomy and Space Sciences
• /
• v.36 no.3
• /
• pp.121-131
• /
• 2019

The ionospheric mid-latitude trough (IMT) is the electron density depletion phenomenon in the F region during nighttime. It has been suggested that the IMT is the result of complex plasma processes coupled to the magnetosphere. In order to statistically investigate the characteristics of the IMT, we analyze topside sounding data from Alouette and ISIS satellites in 1960s and 1970s. The IMT position is almost constant for seasons and solar activities whereas the IMT depth ratio and the IMT feature are stronger and clearer in the winter hemisphere under solar minimum condition. We also calculated transition heights at which the densities of oxygen ions and hydrogen/helium ions are equal. Transition heights are generally higher in daytime and lower in nighttime, but the opposite aspects are seen in the IMT region. Utilizing the Incoherent Scatter Radar (ISR) electron temperature measurements, we find that the electron temperature in the IMT region is enhanced at night during winter. The increase of electron temperature may cause fast transport of the ionospheric plasma to the magnetosphere via ambipolar diffusion, resulting in the IMT depletion. This mechanism of the IMT may work in addition to the simply prolonged recombination of ions proposed by the traditional stagnation model.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.2
• /
• pp.241-246
• /
• 2021

In this paper, hydrogenated amorphous silicon(a-Si:H) grating coupler with distributed Bragg reflector(DBR) is proposed to achieve high-efficiency nanophotonic radiator for Light Detection and Ranging(LiDAR) application. The DBR reduces downward leakage of the optical field below the grating region. As a result, the far-field intensity shows about 1.4 times stronger, compared to the common grating coupler without the DBR.

• Journal of the Korean Society of Industry Convergence
• /
• v.23 no.6_2
• /
• pp.1103-1110
• /
• 2020

In this study, a segmented model with Upside-Down bathtub shaped failure intensity for a repairable system are proposed under the assumption that the occurrences of the failures of a repairable system follow the Non-Homogeneous Poisson Process. The proposed segmented model is the compound model of S-PLP and LIP (Segmented Power Law Process and Logistic Intensity Process), that fits the separate failure intensity functions on each segment of time interval. The maximum likelihood estimation is used for estimating the parameters of the S-PLP and LIP model. The case study of system A shows that the S-PLP and LIP model fits better than the other models when compared by AICc (Akaike Information Criterion corrected) and MSE (Mean Squared Error). And it also implies that the S-PLP and LIP model can be useful for explaining the failure intensities of similar systems.