• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.9
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• pp.315-324
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• 1983

Dynamic stability problems have been experienced with a generator connected to an infinite bus through a long transmission line. Nuclear turbine-generator units #1 and #2 at the Winsconsin Electric Power Point Baech Station were found to be dynamically unstable when one unit is isolated on one of the lines to Milwaukee or when two units are isolaed on the lines to milwaukee. Power System Stabilizers(PSS) were applied to the excitation system to provide stable operation under these conditions. Suitable settings for the PSS were predetetermined analytically by computer method and root licus analysis of an equivalent single machine-infinite bus configuration. This procedure allows graphical approach to the design of power stabilizers and serves as assynthesis procedure when the design constraints are relaxed so the the speed stabilizer is required ro provide animprovement in system damping. A simplified model of the complete exciter generator system is shown to be adequate for this type of analysis.

• Toxicological Research
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• v.28 no.4
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• pp.209-216
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• 2012

The biological activity of particles is largely dependent on their size in biological systems. Dispersion in the aqueous phase has been both a critical impediment to and a prerequisite for particle studies. Carbon black has been used as a surrogate to investigate the biological effects of carbonaceous particles. Here, biocompatible methods were established to disperse carbon black into ultrafine and fine particles which are generally distinguished by the small size of 100 nm. Carbon black with a distinct particle size, N330 and N990 were suspended in blood plasma, cell culture media, Krebs-Ringer's solution (KR), or physiological salt solution (PSS). Large clumps were observed in all dispersion preparations; however, sonication improved dispersion - averaged particle sizes for N330 and N990 were $85.0{\pm}42.9$ and $112.4{\pm}67.9$ nm, respectively, in plasma; the corresponding sizes in culture media were $84.8{\pm}38.4$ and $164.1{\pm}77.8$ nm. However, sonication was not enough to disperse N330 less than 100 nm in either KR or PSS. Application of Tween 80 along with sonication reduced the size of N330 to less than 100 nm, and dispersed N990 larger than 100 nm ($73.6{\pm}28.8$ and $80.1{\pm}30.0$ nm for N330 and $349.5{\pm}161.8$ and $399.8{\pm}181.1$ nm for N990 in KR and PSS, respectively). In contrast, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) exhibited little effect. Electron microscopy confirmed the typical aciniform structure of the carbon arrays; however, zeta potential measurement failed to explain the dispersibility of carbon black. The methods established in this study could disperse carbon black into ultrafine and fine particles, and may serve as a useful model for the study of particle toxicity, particularly size-related effects.

• Korean Journal of Materials Research
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• v.29 no.2
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• pp.87-91
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• 2019

We report on stretchable electrochromic films of poly(3-hexylthiophene) (P3HT) fabricated on silver nanowire (AgNW) electrodes. AgNWs electrodes are prepared on polydimethylsiloxane (PDMS) substrates using a spray coater for stretchable electrochromic applications. On top of the AgNW electrode, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is introduced to ensure a stable resistance over the electrode under broad strain range by effectively suppressing the protrusion of AgNWs from PDMS. This bilayer electrode exhibits a high performance as a stretchable substrate in terms of sheet resistance increment by a factor of 1.6, tensile strain change to 40 %, and stretching cycles to 100 cycles. Furthermore, P3HT film spin-coated on the bilayer electrode shows a stable electrochromic coloration within an applied voltage, with a color contrast of 28.6 %, response time of 4-5 sec, and a coloration efficiency of $91.0cm^2/C$. These findings indicate that AgNWs/PEDOT:PSS bilayer on PDMS substrate electrode is highly suitable for transparent and stretchable electrochromic devices.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.53-55
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• 2002

This paper presents a part of system study results for UPFC Pilot Plant application in Korea. The system study includes control limits of UPFC Pilot Plant. Expansion of control limits is studied by coordination to switched shunt capacitors in local areas. The system study is simulated by PSS/E Ver 26.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.397-398
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• 2007

Currently, most of Passenger Service System is supported to VOD in Korea. This current PSS has not internet access, real time broadcasting system and entertainment. The system did not come up to the expectation of consumer. This paper presents an application of new Passenger Service System for developing multimedia as well as wireless communication technology on internet, satellite broadcasting.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.112-116
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• 1996

This paper presents the study results of FACTS application plan for transmission capability Enhancement. Power transfer across the KEPCO system resulting from a concentration of load in the Kyung-In area are subject to thermal, voltage and stability constrains. In the analysis study of the KEPCO system in 2000 and 2006 year. voltage stability analysis. modal analysis and dynamic stability were simulated by the power system analysis tools(VSTAB, PSS/E).

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.63-65
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• 2007

Recently with increase consumption of electric power, the scale of the electric system becomes bigger and complex. Then, it is increasing the hardship in the operation of electric system and the continuance of stability. Especially, as the differences between demand and supply in electric power keeping low frequency oscillating attenuation from electric power have been very important in the continuance part of stability. The more control time of electricity system is getting faster with digitalization the more stability of electricity system is getting worse. As solutions of these problems, by establishing Power System Stabilizing Controller putting PSS output signal and putting damping to vibration of the rotor at generators's AVR in area where is oscillated, We are willing to contribute the electricity system by holding in generator output vibration.

• Journal of The Korean Society of Clinical Toxicology
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• v.18 no.2
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• pp.94-101
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• 2020

Purpose: This study examined the clinical and epidemiological characteristics of intensive care unit (ICU) patients admitted or died in the emergency medical center with acute-poisoning to investigate the variables related to the prognosis. Methods: The data were collected from poisoning patients admitted or died in the emergency medical center of a general hospital located in Seoul, from January 2014 to February 2020. The subjects of this study were 190 patients. The medical records were screened retrospectively, and the clinical and epidemiological characteristics of the patients in the emergency room (ER) and ICU were examined to investigate the contributing factors that influence the poor prognosis. Results: The study analyzed 182 patients who survived after being admitted to the intensive care unit (ICU). The results are as follows. The mental change (87.4%) was the most common symptom. Sedative poisoning (49.5%) was the commonest cause. For most patients, pneumonia (26.9%) was the most common complication. Hypotension (23.7%), tachycardia (42.1%), fever (15.8%), seizures (10.5%), dyspnea (2.6%), high poisoning severity score (PSS), type of toxic material, mechanical ventilator application (39.5%), inotropes application (39.5%), and pneumonia (55.3%) were correlated the LOS over 5 days in the ICU. 8 patients died. In the case of death pesticides and carbon monoxide were the main toxic materials; tachycardia, bradycardia, and hypotension were the main symptoms, and a mechanical ventilator and inotropes were applied. Conclusion: Patients with unstable vital signs, high PSS, and non-pharmaceutical poisoning had a prolonged LOS in the ICU and a poor prognosis.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.181-187
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• 2013

Identification of main ingredients in starches has been investigated using physicochemical analysis method mainly. However, physicochemical properties such as particle size have limitations in determining the differences among mixed starches. Therefore, we developed a molecular biological method to identify materials used in starch, as a sample, 11 kinds of starches including sweet potato starch, potato starch, corn starch, and tapioca starch. DNeasy plant mini kit, magnetic DNA purification system, and CTAB methods were used to extract DNA from samples. After gene extraction, whole genome amplification (WGA) was performed to amplify the extracted DNA. Species-specific primers were used as followings: ib-286-F/ib-286-R (105 bp), Pss 01n-5'/Pss 01n-3' (216 bp), SS11b 3-5'/SS11b 3-3' (114 bp), and SSRY26-F/SSRY26-R (121 bp) gene for sweet potato, potato, corn, and tapioca, respectively. In this study, we could confirm the main ingredients using WGA and PCR method.

• Science of Emotion and Sensibility
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• v.25 no.1
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• pp.29-40
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• 2022

This study uses the bidet 4D double diamond design process model to propose an improvement for "senior-oriented bidet product service design" that reflects the characteristics and needs of seniors. This study was based on the product service system concept. To this end, qualitative research on seniors was conducted to derive user value factors, and, based on this, product service ideas were discovered, and a prototype reflecting the usefulness review of a working-level expert group was proposed. First, a "smart application service for user-customized function setting guide" was proposed. A bidet incorporating Internet of Things technology and a smart phone are linked to provide an app service that automatically interprets user characteristic information and information on bidet products to guide customized functions. Second, a control panel and remote control user interface to "user-oriented product service interface" was proposed. In consideration of the usability and cognitive ability of seniors, a simple and intuitive physical user interface such as a configuration centered on main functions, button arrangement according to task sequence, and a touch screen remote control was presented. Third, we proposed a "bidet care service linked with products and health/hygiene care" that provides a wide range of services such as user health and hygiene, cleanliness, entertainment, etc., in addition to regular bidet product service. This study proposed a product-based service design methodology that can improve user experience and relationship quality by discovering and improving the pain points and needs of users (seniors) in the process of using bidet products (before, during, and after use).