• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.11
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• pp.21-30
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• 1998

In this paper, a digital current control system using a FPGA(Field Programmable Gate Array) was implemented, and the system was applied to an induction motor widely used as an industrial driving machine. The FPGA designed by VHDL(VHSIC Hardware Description Language) consists of a PWM(Pulse Width Modulation) generation block, a PWM protection block, a speed measuring block, a watch dog timer block, an interrupt control block, a decoder logic block, a wait control block and digital input and output blocks respectively. Dedicated clock inputs on the FPGA were used for high-speed execution, and an up-down counter and a latch block were designed in parallel, in order that the triangle wave could be operated at 40 MHz clock. When triangle wave is compared with many registers respectively, gate delay occurs from excessive fan-outs. To reduce the delay, two triangle wave registers were implemented in parallel. Amplitude and frequency of the triangle wave, and dead time of PWM could be changed by software. This FPGA was synthesized by pASIC 2SpDE and Synplify-Lite synthesis tool of Quick Logic company. The final simulation for worst cases was successfully performed under a Verilog HDL simulation environment. And the FPGA programmed for an 84 pin PLCC package was applied to digital current control system for 3-phase induction motor. The digital current control system of the 3 phase induction motor was configured using the DSP(TMS320C31-40 MHz), FPGA, A/D converter and Hall CT etc., and experimental results showed the effectiveness of the digital current control system.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.574-582
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• 1997

Background : Normal humans meet the increased ventilatory need during exercise initially by the increase of tidal volume (TV) and later by the increase of respiratory frequency (Rf). And the inspiratory duty cycle (Ti/Ttot) is also increased more than 50% for the compensation of the decrease of respiratory cycle provoked by the increase of respiratory frequency. The patients with chronic airflow obstruction show rapid and shallow breathing pattern during exercise because of the decreased ventilatory capacity and the increased dead space ventilation. However, the studies about the change of inspiratory duty cycle are only a few and there is no literature about the relationship between the change of inspiratory duty cycle and the degree of airflow obstruction. Methods : The subjects were the twelve patients with chronic airflow obstruction (CAO) and ten normal people. The incremental exercise test was done. The increase of work load was 10 W in CAO group and 25 W in normal control group. The analysis of the results was done by the comparison of the parameters such as minute ventilation (VE), TV, Rf, physiologic dead space (Vd/Vt), and inspiratory duty cycle between the two groups. Each parameters were compared after transformation into % control duration base that means dividing the total exercise time into five fractions and % control duration data were obtained at rest, 20%, 40%, 60%, 80%, and max. Statistical analysis was done by repeated measure ANOVA using SAS program. Results : The changes of VE and TV were significantly different between two groups while the change of Rf was not significant. The decrease of Vd/Vt was significantly low in CAO group. Ti/Ttot was markedly increased from 38.4 + 3.0% at rest to 48.6 + 4.5% at max in normal control group while Ti/Ttot showed little change from 40.5 + 2.2% at rest to 42.6 + 3.5% at max. And the change of inspiratory duty cycle showed highly good correlation with the degree of airflow obstruction (FEV1%). (r=0.8151, p < 0.05). Conclusions : The increase of Ti/Ttot during exercise observed in normal humans is absent in the patients with CAO and the change of Ti/Ttot is well correlated with the degree of airflow obstruction.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.635-643
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• 2018

This paper propose a method to identify the motor parameters and improve input voltage error which affect the low speed position error of the back-emf(back electromotive force) based sensorless algorithm and to secure the operation reliability and stability even in the case where the load fluctuation is severe and the start and low speed operation frequently occurs. In the model-based observer used in this paper, stator resistance, inductance, and input voltage are particularly influential factors on low speed performance. Stator resistance can cause resistance value fluctuation which may occur in mass production process, and fluctuation of resistance value due to heat generated during operation. The inductance is influenced by the fluctuation due to the manufacturing dispersion and at a low speed where the change of the current is severe. In order to find stator resistance and inductance which have different initial values and fluctuate during operation and have a large influence on sensorless performance at low speed, they are commonly measured through 2-point calculation method by 2-step align current injection. The effect of voltage error is minimized by offsetting the voltage error. In addition, when the command voltage is used, it is difficult to estimate the back-emf due to the relatively large distortion voltage due to the dead time and the voltage drop of the power device. In this paper, we propose a simple circuit and method to detect the voltage by measuring the PWM(Pulse Width Modulation) pulse width and compensate the voltage drop of the power device with the table, thereby minimizing the position error due to the exact estimation of the back-emf at low speed. The suitability of the proposed algorithm is verified through experiment.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.4
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• pp.48-57
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• 1997

This paper presents the automatic construction and parameter optimization technique for fuzzy logic controllers using genetic algorithm. In general. the design of fuzzy logic controllers has difficulties in the acq~lisition of expert's knowledge and relies to a great extent on empirical and heuristic knowledge which, in many cases, cannot be objectively justified. So, the performance of the controllers c:an be degraded in the case of plant parameter variations or unpredictable incident which a designer may have ignored, and the parameters of fuzzy logic controllers obtained by expert's control action may not be optirnal. Some of these problems can be resolved by the use of genetic algorithm. The proposed method can tune the parameters of fuzzy logic controllers including scaling factors and determine: the appropriate number of fuzzy rulcs systematically. Finally, we provides the second order dead time plant to evaluate the feasibility and generality of the proposed method. Comparison shows that the proposed method can produce fuzzy logic controllers with higher accuracy and a smaller number of fuzzy rules than manually tuned fuzzy logic controllers.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.575-585
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• 2000

This study was performed to observe the influence of host immune response on the chemotherapy of mice experimentally infected with Fasciola hepatica. Following immunosuppression with prednisolone or immunoenhancement with Freund's complete adjuvant(FCA), mice were experimentally infected with 3 Fasciola hepatica metacercariae and treated with closantel at 1 week post infection. In the group of mice infected with metacercariae alone, 2 mice of 10 were dead at 10 weeks post infection(20% mortality), and adult flukes were recovered from the liver and the peritoneal cavity of the remaining 8 mice(100% infectivity). In the group of mice treated with prednisolone and infected with metacercariae, 8 of 10 mice died before euthanasia with a mean time of death earlier than the control group (p<0.05). In the group of immunosuppressed mice infected with metacercariae and treated with closantel 20mg/kg, 4 of 10 mice died before sacrifice. In the group of mice infected and treated with closantel 20mg/kg, mortality and infectivity was 10% and 30%, respectively. Similar results were observed in mice infected and treated with closantel 5mg/kg which resulted in 10% and 50% mortality and infectivity, respectively. These results indicated that the efficacy of closantel treatment was decreased in immunosuppressed mice, while the pathogenicity was increased. In immunoenhanced mice infected with metacercariae, on the other hand, the efficacy of chemotherapy with both 5mg/kg or 20mg/kg closantel resulted in only 10% infectivity. The results shown in this study strongly suggest that a close interaction between chemotherapy against F hepatica with closantel and the host immune system exists. Considering that fascioliasis is a zoonosis, treatment regimen against the infection to immunosuppressed patients may require a concurrent prescription of an appro-priate immuno-enhancing adjuvant.

• The Korean Journal of Emergency Medical Services
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• v.9 no.1
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• pp.33-41
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• 2005

In Korea, the number of those who were drowned of the dead by 'accident and injury' ranked the third of causes of death is over 2,300 people a year. So the Ministry of Home Affairs arranged '119 drowning rescue team' at frequent occurrence regions of drowning temporarily as a part of drowning rescue measures during every summer season and made perfection more perfect for safety control and rescue services at prevention areas of accidents. However, considering that the number of professional drowning rescuers is small and it is managed temporarily only for summer, the placement of special rescue team equipped with professional education and qualification should be ensured and quick lifesaving and first-aid treatment should be conducted, since much time is required to arrive at accident place after receiving accident report at 119 office, rapid rescue and relief have not been achieved. Therefore, the placement of special rescue team should be increased for reducing the personal damages by considering regional characteristics and in particular placement of more drowning rescue teams in Jeonnam region which has more seas and rivers is needed This study aims at analyzing relief activities and statistics to cope with water accidents and achieve qualitative growth of first-aid services, examining actual conditions of water accident relief team and personnel assignment, providing first-aid services of good quality and establishing improvement methods to increase operation of relief team.

• Journal of Korean Society of Rural Planning
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• v.21 no.4
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• pp.77-84
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• 2015

The purpose of this study is to interpret Landscape of Naeap Village which still preserves the Confucian culture and the traditional clans among the ideally settled villages mentioned in Joong Hwan Lee's "Taengniji" and "Joseon's Fengsui" from the time of Japanese Imperial Rule, from CPTED principles. The following are the findings of this study: First, in terms of access control and zoning, Naeap Village was controlling access from the outside with the natural environment of Banbyeoncheon River and the hills surrounding the village, the artificial environment of human-scale walls around the head house and the dead ends, and the reformation by the Confucian ideologies. Naeap Village, in particular, is prominently configured by the hierarchy of zones; the Gaehosong pine trees, Gyeongpodae, and Naeapssu by the entrance to the village are considered the village itself and the landscapes and valleys are managed by the head house. Second, the Confucian culture across the village, the traditional vegetation method that does not hide the visibility, and the workers in the farms allow natural monitoring. The surrounding visibility is also applied to the spirit of mutual cooperation in the farming society, the culture of commoners at the common well and laundry site, and the culture of ruling class at the towers and pavilions. Third, Traditional villages show the efforts to preserve and maintain the villages with the village rules, the organizational decrees of the clan, and active response to national disasters.

• Ocean and Polar Research
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• v.31 no.4
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• pp.349-357
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• 2009

Ballast water is widely recognized as a serious environmental problem due to the risk of introducing non-indigenous aquatic species. In this study we aimed to investigate measures which can minimize the transfer of aquatic organisms from ballast water. Securing more reliable technologies to determine the viability of aquatic organisms is an important initiative in ballast water management systems. To evaluate the viability of marine phytoplankton, we designed the staining methods of fluorescein diacetate (FDA) and Calcein-AM assay on each target species belonging to different groups, such as bacillariphyceae, dinophyceae, raphidophyceae, chrysophyceae, haptophyceae and chlorophyceae. The FDA method, which is based on measurements of cell esterase activity using a fluorimetric stain, was the best dye for determining live cells of almost all phytoplankton species, except several diatoms tested in this study. On the other hand, although fluorescence of Calcein-AM was very clear for a comparatively longer time, green fluorescence per cell volume was lacking in most of the tested species. According to the Flow CAM method, which is a continuous imaging technique designed to characterize particles, green fluorescence values of stained cells by FDA were significantly higher than those of Calcein-AM treatments and control, implying that the Flow CAM using FDA assay could be adapted as an important tool for distinguishing living cells from dead cells. Our results suggest that the FDA and Calcein-AM methods can be adapted for use on phytoplankton, though species-specific characters are greatly different from one organism to another.

• Journal of Biosystems Engineering
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• v.31 no.5 s.118
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• pp.436-442
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• 2006

This research was conducted to design and develop a wired monitoring system for judging if sick or dead layers (SDL) exist in multi-tier layers battery (MLB) by machine vision, and to analyze its performance. In this study, 20 Brown Leghorn (Hi-Brown) layers aged 37 weeks old, were used as the experimental animals. The intensity of concern paid by layers on feed was over 90% during 5 minutes and 30 seconds after providing feed, and normal layers (NL) had been standing to take feed for that period. Therefore, in this study, the optimal judging time was set by this test result. The wired monitoring system developed was consisted of a driving device for carrying machine vision systems, a control program, a RS232 to RS485 convertor, an automatic positioning system, and an image capture system. An image processing algorithm was developed to find SDL in MLB by the processes of binary processing, erosion, expansion, labeling, and reckoning central coordinate of the captured images. The optimal velocity for driving unit was set up as 0.13 m/s by the test results for wired monitoring system, and the proximity switch was controlled not to be operated for 1.0 second after first image captured. The wired monitoring system developed was tested to evaluate the remote monitoring performance at lab-scale laying hen house. Results showed that its judgement success.ate on normal cage (without SDL) was 87% and that on abnormal cage (with SDL) was 90%, respectively. Therefore, it would be concluded that the wired monitoring system developed in this study was well suited to the purpose of this study.

• YAKHAK HOEJI
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• v.45 no.2
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• pp.190-204
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• 2001

This study was conducted to investigate for its effects on reproductive and developmental toxicity of recombinant human epidermal growth factor (rhEGF) in Sprague-Dawley rats. Male rats were administered rhEGF at doses of 1, 10, 100, and 1000$\mu$g/kg/day, respective1y, by subcutaneous injection from 63 days before and throughout to mating period until the day before sacrifice. Female rats were administered rhEGF at the same doses from 14 days before mating to day 20 of gestation or to day 21 of lactation. We examined the male and female fertility indices and maternal toxicity of F0 parental animals. Also, we examined the external, visceral, or skeletal malformation of fetuses, growth and development, behavior, and/or reproductive performance of F1 animals. At the highest dose (1,000 $\mu$g/kg), the mean body weights of F0 animals were significantly increased in males and females at 3 or 2 weeks after treatment, respective1y. No clinical signs and food intakes were observed at any time during the experimental period by rhEGF treatment. In autopsy examination, the relative and absolute liver weights significantly increased in both sexes of 1,000 $\mu$g/kg. At the highest dose (1,000 $\mu$g/kg), there was a statistically significant increase of pregnancy period and the number of dead fetuses. Moreover, significant increase of mean fetal body weight and decrease of number of live fetuses, which related to the difficult dilivery were observed in highest dose group. In Fl examination, no adverse effects on external, visceral, and skeletal malformation, physical and functional development, behavior or reproductive ability of Fl animals were observed in any group. Also, there was no significant difference between control and treated groups in copulation or fertility indices of Fl animals. These results indicate that rhEGF had no adverse effect on fertility and reproductive ability of Sprague-Dawley rats.