• Journal of Korean Biological Nursing Science
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• v.21 no.4
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• pp.300-307
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• 2019

Purpose: The purpose of this study was to provide basic data on the infection prevention management program, which is one of the infectious disease control program by identifying the prevalence and risk factors of latent tuberculosis infection (LTBI) in healthcare workers. Methods: We surveyed a total of 3,046 LTBI test results, including those of 2,269 existing staff and 777 new employees. An interferon-gamma release assay (IGRA) for the diagnosis of LTBI was performed using QuantiFERON^®-TB Gold In-Tube (QFT-IT). The risk factors of LTBI were analyzed using logistic regression analysis. Results: The overall prevalence of LTBI was 16.0% (487/3,046). The prevalence of LTBI in the existing staff was 17.9% (406/2,269) and the prevalence of LTBI in new employees was 10.4% (81/777). Multivariate logistic regression analysis revealed that the risk factors of latent tuberculosis infection among the existing staff were gender, age and work period wheres, the risk factor amongst the new employees depended on their age. Conclusion: The LTBI was not related to the type of occupation and work unit. Therefore, while establishing an infection control program for the prevention of tuberculosis infection at medical institurions, institutional heads and infection control experts should encompass a policy for all the employees.

• Journal of Environmental Science International
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• v.7 no.2
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• pp.133-140
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• 1998

To investigate the effects of sulfite on the chloroplast development, etiolated barley seedlings were treated with 100 mM sulfite solution every 3 hour by spraying during 96 hours greening Period. The effects were determined by chlorophyll a, b and carotenoids contents, photosynthetic electron transport activity, chlorophyll fluorescence yield and fluorescence quenching parameters. The contents of chlorophyll a and carotenoids were decreased than that of control by treatment of salfite over 48 hours greening. PS II Is more sensitive to sulfite than PS I Is. And by the addition of DPC to the chloroplasts of the barley seedling treated with sulfite, the photoreduction of DCPIP was not recovered. In greening with suite treated barley leaves, Fo, Fv and Nlh ratio were decreased with little difference from that of control. But qP, qNP and qR were lowed in comparison with those of controls whereas qE was markedly higher than that of control. Especially, It is Interesting that qR was decreased markedly compared to that of control. The results in the change of PS I activity, Nf and qP suggest that the strate of Inhibition by suite Is carbon dioxide reduction cycle.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.8
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• pp.557-564
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• 2000

A very simple control approach using neural network for the robust position control of a Permanent Magnet Synchronous Motor(PMSM) is presented. The linear quadratic controller plus feedforward neural network is employed to obtain the robust PMSM system approximately linearized using field-orientation method for an AC servo. The neural network is trained in on-line phases and this neural network is composed by a feedforward recall and error back-propagation training. Since the total number of nodes are only eight, this system can be easily realized by the general microprocessor. During the normal operation, the input-output response is sampled and the weighting value is trained multi-times by error back-propagation method at each sample period to accommodate the possible variations in the parameters or load torque. In addition, the robustness is also obtained without affecting overall system response. This method is realized by a floating-point Digital Signal Processor DS1102 Board (TMS320C31).

• Preventive Nutrition and Food Science
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• v.18 no.3
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• pp.203-209
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• 2013

The objective of the present study was to evaluate the physicochemical and microbial properties of the Korean traditional rice wine Makgeolli, supplemented with banana during 6 day fermentation. The alcohol contents of the control and banana Makgeolli were 17.0 and 16.5%, respectively. The pH values decreased while total acidity, total soluble solids, and color values increased throughout the fermentation process. An increase in microorganism counts throughout the 6-day fermentation period was noted in all samples. The major free sugar and organic acid detected in all samples were glucose and succinic acid, respectively. There were 39 volatile compounds detected in the control and banana Makgeolli. The major ester detected was ethyl acetate (20.037 and 22.604% for the control and banana Makgeolli, respectively). The major alcohol compounds detected were 3-methylbutanol (20.933%) and 3-methyl-1-butanol (34.325%) in the control. 2-mtehyl-1-propanol (22.289%) and 3-methyl-1-butanol (39.851%) were the highest alcohol compounds detected in the banana Makgeolli.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.284-287
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• 1987

In this paper, the design and implementation of a multiprocessor based Die Bonder Machine for the semiconductor will be described. This the partial research result, that is, the 1st year portion of the project to be performed for a period of two years from June, 1986 to May, 1988. The mechanical system consists of the following three subsystems : (i) transfer head unit, (ii) die feeding XY-table unit, and (iii) plunge up unit. The overall control system is designed to be essentially a master-slave type in which each slave is functionally fixed in view of software and also the time shared common bus structure with hardwired bus arbitration scheme is utilized, the control system consists of the following three subsystems each of which employs a 16 bits microprocessor MC 68000 : (i) die bonder processor controller, (ii) visual recognition/inspection and display system, (iii) the servo control system. It is reported that the proposed control system were applied to Working Sample and tested in real system, and the results are successful as a working sample phase.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.918-925
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• 2008

Controlling the light energy and major nutrients is important for high cell density culture of cyanobacterial cells. The growth phase of Anabaena variabilis can be divided into an exponential growth phase and a deceleration phase. In this study, the cell growth in the deceleration phase showed a linear growth pattern. Both the period of the exponential growth phase and the average cell growth rate in the deceleration phase increased by controlling the light intensity. To control the light intensity, the specific irradiation rate was maintained above $10\;{\mu}mol/s/g$ dry cell by increasing the incident light intensity stepwise. The final cell density increased by controlling the nutrient supply. For the control of the nutrient supply, nitrate, phosphate, and sulfate were intermittently added based on the growth yield, along with the combined control of light intensity and nutrient concentration. Under these control conditions, both final cell concentration and cell productivity increased, to 8.2 g/l and 1.9 g/l/day, respectively.

• International Journal of Safety
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• v.10 no.2
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• pp.10-15
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• 2011

The reconfigurable control systems based on feedback controls are utilized to compensate for damages of actuators in control systems. Such systems have multiple feedback controls and switch them in accordance with the degrees of the failures of the actuators. In order to be able to assess those systems, this paper develops a method to obtain reliabilities of reconfigurable dynamical systems which are interconnected in parallel / series configuration. By calculating reliabilities of interconnected dynamical systems, it is possible to assess many dynamical systems by comparing their reliabilities. Firstly, reliabilities of subsystems are obtained according to the definitions of the failures in terms of robust reliability for each subsystem. Then, the reliability of overall system is calculated from reliabilities of subsystems, using the methodology employed for probabilistic safety assessment. Failure rates of subsystems with feedbacks for reconfiguration change in certain time periods because of the switching of feedback controls. In order to deal with this, combinations of subsystems which compose overall system for each time period are derived by the methodology mentioned above and then integrated to calculate the reliability of overall system for a specific time. An illustrative example shows the validity and details of the proposed method.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.1
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• pp.38-43
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• 2011

This paper presents the improvement of start-up characteristic of sensorless controlled IPMSM(Interior Permanent Magnet Synchronous Motor) with SMO(Sliding Mode Observer). It is difficult to utilize the rotor position information at starting point for the back EMF estimation based sensorless control. For this reason, open loop control is normally used during start-up period. However, changing from open loop to closed loop control might bring a problem on the transient characteristics for difference load conditions. To solve this problem, we add another rotor angle controller. Simulation results and experimental results are presented to verify proposed method.

• Journal of Power Electronics
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• v.18 no.1
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• pp.251-265
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• 2018

To enable a master-slave control independent microgrid system (MSCIMGS) to supply electricity continuously, the microgrid inverter should perform mode transfer between grid-connected and islanding operations. Transient oscillations should be reduced during transfer to effectively conduct a seamless mode transfer. This study uses a typical MSCIMGS as an example and improves the mode transfer strategy in three aspects: (1) adopts a status-tracking algorithm to improve the switching strategy of the outer loop, (2) uses the voltage magnitude and phase pre-synchronization algorithm to reduce transient shock at the time of grid connection, and (3) applies the hybrid-sensitivity $H_{\infty}$ robust controller instead of the current inner loop to improve the robustness of the controller. Simulations and experiments show that the proposed strategy is more practical than the traditional proportional-derivative control mode transfer and effective in reducing voltage and current oscillations during the transfer period.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.117-118
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• 2003

This experiment was conducted to investigate the effect of feed restriction in early stage of growth on the compensatory growth in male and female broiler chickens. Day-old 480 male and 480 female commercial broiler chickens(Ross strain) were randomly allotted to 32 pens(replicates), 30 birds per pen, to compare the sex difference in growth performance and carcass characteristics. Birds in control group(C) were full fed throughout the study. T1, T2 and T3 were restricted at 4∼11d, 4∼14d and 4∼18d, respectively. Chickens were weighed every week, and one bird was selected from each pen to measure carcass characteristics at the end of experiment. In female chickens, all restricted-fed groups except for T3 weighed same as or heavier than the control group at 7 weeks of age. In male chickens, both T2 and T3 that had longer feed restriction period were significantly different from the control group. Viability was not different significantly. Feed intake in both male and female chickens of T3 group statistically differed from the control group. The female chicks showed larger abdominal fat pad sizes than did male birds up to market age.