• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.111-117
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• 1998

The effect of chitosan on physicochemical and organoleptic properties of Nabak kimchi was studied during fermentation at 2$0^{\circ}C$ . Viscosity of the juice of Nabak kimchi added with chitosan was lower than that of control group. The viscosity was gradually increased during storage period, especially from 5 days to ,7 days of storage. Initial pH was higher in control group than inchitosan groups. The pH of controlgroup decreased rapidly during 4 days of storage. The pH of chitosan groups was slightly increased during the first 3 days of storage and decreased thereafter. Acidity was rapidly increased from 3 to 5 days. Reducing sugar contents increased up to 3 days and decreased thereafter. Acidity was rapidly increased from 3 to 5 days. Reducing sugar contents increased upto 3 days and decreased therafter. Glutamic acid, alanine, threonine, aspartic acid, proline and valine were the major free amino acids, and as the fermentation preceeded they were increased gradually. There were signigicant differences in saltiness, sourness and aged odor in sensory evaluation of Nabak kimchi solution during fermentation at 2$0^{\circ}C$.

• Journal of Korean Institute of Industrial Engineers
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• v.14 no.2
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• pp.131-141
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• 1988

As flexible manufacturing technology has become available across a broad range of applications, an increasingly large number of firms have confronted decisions about when to adopt the FMS technology and the size of FMS at that time. For small to medium size firms that should invest under budget limitation and high investment risk, proper size of FMS adoption at proper time is very important. In this paper the discrete optimal control theory has been used to make decisions about the size and timing of FMS capacity expansion over a planning period. Sensitivity analysis is presented for analysing the behavior of the model to variations of model parameters.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.511-513
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• 2004

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position, because the position of rotor is an essential information. In the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost analog encoder suitable for practical applications is proposed. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.

• Journal of information and communication convergence engineering
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• v.11 no.3
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• pp.199-206
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• 2013

An emergency monitoring system for the elderly, which uses acceleration data measured with an accelerometer, angular velocity data measured with a gyroscope, and heart rate measured with an electrocardiogram, is proposed. The proposed fall detection algorithm uses multiple parameter combinations in which all parameters, calculated using tri-axial accelerations and bi-axial angular velocities, are above a certain threshold within a time period. Further, we propose an emergency detection algorithm that monitors the movements of the fallen elderly person, after a fall is detected. The results show that the proposed algorithms can distinguish various types of falls from activities of daily living with 100% sensitivity and 98.75% specificity. In addition, when falls are detected, the emergency detection rate is 100%. This suggests that the presented fall and emergency detection method provides an effective automatic fall detection and emergency alarm system. The proposed algorithms are simple enough to be implemented into an embedded system such as 8051-based microcontroller with 128 kbyte ROM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.593-603
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• 1997

Connection admission decision in ATM networks requires decision made in real time using fast algorithm. It is difficult to construct a model of the multiplexed traffic and thus, approximation of the traffic load is necessary. In this paper, we propose a measurement-based dynamic CAC(Connection admission Control) in ATM(Asynchronous Transfer Mode) networks, which observes current traffic by the moving window and set the window size to the value which is computed from the measured cell loss amount. It is based on the measurements of the traffic load over an admission period that is load enough to reflect the current traffic behavior instead of analytic modeling. And, the dynamic reallocation of bandwidth for each class leads to effective bandwidth utilization. The performance of proposed method is analyzed through computer simulation. The performance of proposed method is analyzed by using SIMAN simulation package and FORTRAN language. As can be seen in the simulation result, cell loss performance and bandwidth utilization have been increased.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.166-171
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• 2002

We are in transitional period of welding technique, which has changed from the stage of quantity and quality to the stage of future technique, imported and introduced from many advanced countries. Therefore, many researches and studies for development on high speeding and making welding machines with high effectiveness has been doing vigorously. In this dissertation, I have studied on a pulsed MAG welding machine, with which welding of thin plates may perform high speeding and effecting. First, I produced a phase shifted full bridge DC-DC convert, which is the type of reduced conduction loss and the power supply for welding machine. And then, I found out an output waveform control algorithm about one pulsed one droplet and short waveform control for thin plates with high speed by deriving the circuit model utilizing the circuit averaged method for full bridge converter.

• Journal of Power Electronics
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• v.12 no.6
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• pp.912-924
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• 2012

In hybrid renewable power systems, the use of a multiple-input dc/dc converter (MIC) leads to simpler circuit and lower cost, when compared to the conventional use of several single-input converters. This paper proposed a novel three-input buck/boost/buck-boost converter, which can be used in applications with various values of input voltage. The energy sources in this converter can deliver power to the load either simultaneously or individually in one switching period. The steady relationship, the power management strategy and the small-signal circuit model of this converter have been derived. With decoupling technology, modeling and regulator design can be obtained under multi-loop control modes. Finally, three generating methods of a multiple-input buck/boost/buck-boost converter is given, and this method can be extended to the other multiple-input dc/dc converters.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.114-117
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• 1999

표고 시설재배에서의 고품질 표고(동고, 화고)의 생산환경 분석을 위하여 차광재배와 시설재배사의 환경을 분석하여 각 시설내의 환경조건을 분석하였다. 차광재배사와 시설재배사의 기상환경 분석 결과, 시설재배의 습도는 차광재배에 비하여 20-40%높게 나타났으며, 70-80% 이상인 기간이 차광재배에 비하여 약2배 가량 높게 나타났다. 생육기간중 시설재배에서의 최고온도가 저온성 표고의 생육 온도보다 2-4$^{\circ}C$ 높아 생육에 악 영향 준 것으로 판단된다. 골목 하부로 갈수록 시설재배에서 4-5$^{\circ}C$ 높게 나타났다. 시설재배의 $CO_2$의 농도는 차광재배에 비하여 100-200ppm 정도 높게 나타났다. 이상의 결과로부터 시설내의 환기촉진과 과습방지가 시설내의 고품질 표고 생산을 위한 환경개선 방법이라고 판단된다.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.1
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• pp.9-15
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• 2011

Highly pathogenic avian influenza could not be identified visually. It takes time to identify the symptoms by its incubation period. Without taking a quick step, the diffusion area of HPAI has dramatically increased, the extent of damage becomes bigger. In network research, the algorithm of finding the central node on the network applied to various diffusion of epidemic problems, was used in control system of tracing the diffusion path, blocking central nodes. This study tried to make the diffusion of HPAI network model for the crowded farms area, and reduce the diffusion rate to control the high-risk farms.

• Journal of Power Electronics
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• v.6 no.2
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• pp.114-120
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• 2006

This paper compares two types of direct torque controllers for permanent magnet synchronous motors(PMSMs). These controllers both use a single-chip FPGA(Field Programmable Gate Array) but have differing hardware configurations. One of the controllers was constructed by programming a soft-core CPU and hardware logic circuits written in VHDL(Very high speed IC Hardware Description Language), while the other was constructed of only hardware logic circuits. The characteristics of these two controllers were compared in this paper. The results show the controller constructed of only hardware logic circuits was able to shorten the control period and it was able to suppress the low torque ripple.