• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.274-282
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• 2014

Purpose: In this study, a hybrid power system was developed for agricultural machines with a 20-KW output capacity, and it was attached to a multi-purpose cultivator to improve the performance of the cultivator, which was evaluated using output tests. Methods: The hybrid system combined heterogeneous sources: an internal-combustion engine and an electric power motor. In addition, a power splitter was developed to simplify the power transmission structure. The cultivator using the hybrid system was designed to have increased fuel efficiency and output power and reduced exhaust gas emissions, while maintaining the functions of existing cultivators. Results: The fuel consumption for driving the cultivator in the hybrid engine vehicle (HEV) mode was 341 g/KWh, which was 36% less than the consumption in the engine (ENG) mode for the same load. The maximum power take off output of the hybrid power system was 12.7 KW, which was 38% more than the output of the internal-combustion engine. In the HEV mode, harmful exhaust gas emissions were reduced; i.e., CO emissions were reduced by 36~41% and NOx emissions were reduced by 27~51% compared to the corresponding emissions in the ENG mode. Conclusions: The hybrid power system improved the fuel efficiency and reduced exhaust gas emissions in agricultural machinery. Lower exhaust gas emissions of the hybrid system have considerable advantages in closed work environments such as crop production facilities; therefore, agricultural machinery with less exhaust gas emissions should be commercialized. However, the high manufacturing cost and complexity of the proposed system are challenges which need to be solved in the future.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.397-404
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• 2011

In this research, wish to suggest method to embody system that can accommodate defect of PLC and find actual propriety. Defect permission control system minimizes production damage because enables repair and checking without discontinuance and improve believability about whole system. Propose duplexing of system to embody this fault tolerant system. Therefore, composed control system that can permit defect or breakdown duplexings of various module proposing this system, and confirms to simulation and actuality kiln of defect permission control system through an application experiment, and compares for mean time between defect by estimate and defect special quality and system configuration of failure(failure) to improve believability of PLC control system together. In proposed system expression method and system mode and relation with operation mode, error discovery mode and switching tube of duplexing mode, and PLC's central processing unit of node study algorithm about master-standby conversion driving and continuous operation of 2 channels method that have 2 that is not one and deduced continuous operation method and result about defect permission in this algorithm and applies this result to actuality kiln control system and confirms continuous operation about PLC defect permission.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.295-298
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• 2000

In order to maximize the RNA accumulation and biomass production in Saccharomyces cerevisiae MTY62, a high-content RNA yeast strain, fed-bach cultures were performed with optimized industrial medium including molasses and corn steep liquor. Among the feeding modes examined, the constant feeding mode resulted in the cell concentration of 35.7 g-DCW/L and the RNA concentration of 5434 ${\mu}g-RNA/mL$, which were about 2-fold increased levels, compared to the results of bach culture. However, the RNA content (153 mg-RNA/g-DCW) in the fed-batch cultures was lower than that in the batch culture (171 mg-RNA/g-DCW).

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.356-359
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• 2000

A two-stage fed-batch fermentation was carried out to increase xylitol productivity by Candida tropicalis. The first stage for cell growth was performed in the pH-stat and continuous fed-batch modes. The higher cell growth and lower ethanol production obtained in the fed-batch mode where the growth medium was fed when pH of culture broth increased over 5.7. And also the effect of oxygen transfer on xylitol production was investigated by changing agitation speed under 0.5 vvm of aeration. The maximum xylitol productivity and yield were obtained at 500 rpm of agitation.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.11a
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• pp.115-121
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• 2002

The growth of semiconductor industry attracted to researchers like design, facility technique and making small size chip areas. But nowadays, cause of technology extension and oversupply and price down, yield improvement is the most important point on growth. This paper describes the computer mode]ing technique as the solutions to analyze the problem, to formalize the semiconductor manufacturing process and to build advanced manufacturing environments. The computer models are built referring an existing 8' wafer production line in Korea.

• KSBB Journal
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• v.15 no.4
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• pp.346-351
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• 2000

Several solvents or combinations of solvents were tested for the extraction of wet or dried biomass at different extraction mode from plant cell cultures. Methanol gave the highest paclitaxel recovery with the least amount of solvent usage. before extraction drying of biomass wass helpful to decrease solvent usage in extraction step./ in this case drying method was very important to obtain high yield from dried biomass. In thid mode of operation counter-current extraction process can be able to decrease solvent usage but paclitaxel recovery was almost same with both batch and counter-current mode of operation. The number of extraction times was at least four to obtain high yield(>99%) from cell and one to obtain highyield(>96%) from cell debris in batch mode. Equilibrium (i.e. the ratio of paclitaxel in biomass to paclitaxel in the extraction solvent) was reached within 5 minutes. The minimum methodal concentration (90%) and solvent amount(biomass : solvent=1 Kg : 1L) are enough to obtain high yield(>98%) for extraction from biomass.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6B
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• pp.423-432
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• 2012

We design a control circuit that can switch input power between a rechargeable battery and a sensor communication device (mote) depending on the operating state of a solar cell as well as the active and sleep mode of a sensor MAC protocol. A mote that simply combines a solarcell and a rechargeable battery may die if there is not sunlight long. A battery is recharged if sunlight is sufficient and a device is in a sleep mode, and it supplies power if sunlight is low and the mote is in an active mode. A mote can switch its input power between solar cell and battery depending on the output level of a solar cell. During this switching, a mote may lose its state information due to the reset of a microprocessor by the transient power-off. A capacitor is used to cope with this phenomenon and also supplies power to a mote during a sleep mode. Experimental results show that the solar cell based mote operates in a very stable manner against the lack of sunlight long.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.39-46
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• 2014

In this paper, to operate 2.4 GHz Inverted-L antenna with On-Board Broadband characteristics is proposed. The antenna was designed on the system board, the bandwidth by adjusting the reactance of the antenna that was formed common-mode and differential-mode on the antenna stubs has been improved. The system size is $80mm{\times}60mm$, the size of the antenna was limited to $30mm{\times}60mm$, the thickness of FR4 dielectric substrate is 0.8 mm, FR4 dielectric constant 4.4 is used. The experimental results, the bandwidth from 17.2 to 24.1 %, the gain is 3.01~4.71 dB, omni-directional radiation pattern characteristics were obtained. By a mobile terminal design applying the results of the paper, the handset's price competitiveness and production efficiency can be improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.751-758
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• 2021

Munitions must be analyzed to identify any risks for quality assurance in development and mass production. Risk identification for parts, compositions, and systems is carried out through failure mode effects analysis (FMEA) as one of the most reliable methods. FMEA is a design tool for the failure mode of risk identification and relies on the RPN (risk priority number). FMEA has disadvantages because its severity, occurrence, and detectability are rated at the same level. Fuzzy FMEA applies fuzzy logic to compensate for the shortcomings of FMEA. The fuzzy logic of Fuzzy FMEA is to express uncertainties about the phenomenon and provides quantitative values. In this paper, Fuzzy FMEA is applied to the failure mode of a rotorcraft landing system. The Fuzzy rule and membership functions were conducted in the Fuzzy model to study the RPN in the failure mode of a landing system. This method was selected to demonstrate crisp values of severity, occurrence, and detectability. In addition, the RPN was obtained. The results of Fuzzy FMEA for the landing system were analyzed for the RPN and ranking by fuzzy logic. Finally, Fuzzy FMEA confirmed that it could use the data in quality assurance activities for rotorcraft.

• Journal of Platform Technology
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• v.9 no.4
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• pp.42-50
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• 2021

Recently, the need to introduce smart farms is increasing in order to solve the problems of intensifying competition such as a decrease in rural population due to aging, a decrease in production, and the inflow of foreign agricultural products, and accordingly, the need for education is increasing. This paper is a study on the implementation of an Android-based IoT smart farm for education so that it can be used in a real environment by reducing the farm's smart farm system. To confirm that Android-based education can be applied in a real environment using the IoT smart farm for education, experiments were performed in automatic mode and manual mode using Bluetooth, Wi-Fi, and server/client communication methods. In the automatic mode, the current status can be checked in real time by receiving all data, and in the manual mode, commands are transmitted in real time using the received sensor data and remote control is performed. As a result of the experiment, it was possible to understand the characteristics of each communication method, and it was confirmed that remote monitoring and remote control of the smart farm using the Android App was possible.