• Journal of Institute of Control, Robotics and Systems
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• v.22 no.11
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• pp.904-911
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• 2016

This paper presents a novel driving system by the humanoid robot to drive a vehicle in disaster response situations. To enhance robot's capability for substituting human activities in responding to natural and man-made disaster, the one of prerequisite skills for the rescue robot is the mounted mobility to maneuver a vehicle safely in disaster site. Therefore, our driving system for the humanoid is developed in order to steer a vehicle through unknown obstacles even under poor communication conditions such as time-delay and black-out. Especially, the proposed system includes a tele-manipulation interface and stable navigation strategies. First, we propose a new type of path estimation method to overcome limited communication. Second, we establish navigation strategies when the operator cannot recognize obstacles based on Dynamic Window Approach. The effectiveness of the proposed developments is verified through simulation and experiments, which demonstrate suitable system for driving a vehicle in disaster response.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.181-183
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• 2003

This paper presents an operator training simulator for power system restoration against massive black-out. The system is designed especially focused on the generality and convenient setting up for initial condition of simulation. The former is accomplished by using on line calculation methodology, and PSS/E data is used to define the initial situation. The proposed simulator consists of three major components - the Power flow(PF) module, data conversion(CONV) module and CUI subsystem. PF module calculates power flow, and then checks overvoltage of buses and overflow of lines. CONV module composes an Y-Bus array and a data base at each restoration action. The initial Y-Bus array is constructed from PSS/E data. The user friendly GUI module is developed including graphic editor and built-in operation manual. As a result, the maximum processing time for one step operation is 15 seconds, which is adequate for training purpose. Comparison with PSS/E simulation proves the accuracy and reliability of the training system.

• Journal of Digital Contents Society
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• v.12 no.3
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• pp.329-337
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• 2011

Digital talking book has been developed to enhance reading experiences for reading-disabled people. In the existing digital talking book, however, annotations can be created only through the screen interfaces. Screen annotation interfaces is of no use for reading-disabled people because they need reader's eyesight. In this paper, we suggest a voice annotation technique can create notes and highlights at any playing time by using hearing sense and voice command. We design a location determination technique that pinpoints where a voice annotation should be placed in the playing sentences. To verify the effectiveness of our voice annotation technique, we implement a prototype in an android platform. We can find out by the black-blindfolded users testing that our system can perfectly locate the exact position that a voice annotation should be placed into.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.169-174
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• 2012

Electromagnetic interference(EMI) shielding effectiveness(SE) was investigated in of woven fabric made of epoxy/copper-nickel fabrics and nickel coated carbon fiber reinforced acrylonitrile-butadiene-styrene(ABS) composites. The coaxial transmission line method was used to measure the EMI shielding effectiveness of the composites. We designed and constructed a measuring system, consisting of a network analyzer and a device that plays the serves as a sample holder and at the same time as a transmission medium of the incident electromagnetic wave. The measurement of SE were carried out frequency range from 100MHz to 2GHz. It is observed that the SE of the composits is the frequency dependent increase with the increase in nickel coated carbon fibre volume fraction. The nickel coating with 20wt% ABS composite was shown to exhibit up to 60dB of SE. The result that nickel coated carbon fibre ABS composite can be used for the purpose of EMI shielding as well as for some microwave applications.

• Korean Journal of Crystallography
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• v.13 no.1
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• pp.31-35
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• 2002

The possibility of producing the pigments from potash feldspar was studied by adopting the mechanical alloying technique under various gas environments. The experiments were carried out by varying grinding time with the addition of copper metal and titanium oxide in N₂, O₂, He, CO₂, H₂and air atmospheres. The mixture of the potash feldspar concentrate and copper and titanium dioxide are finely ground by a planetary ball mill, and then the composite powders were calcined at 1200℃ for 20 minutes. As a result, the calcined feldspar with 1 wt% of Cu has shown various colors like green in air, black in O₂, dark green in CO₂, brown in H₂, purple in He, and pale green in N₂ atmospheres, respectively.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.54-60
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• 1994

The cause of black out of Tokyo Power in 1987 has been identified as the voltage stability problem. After this event many researchers has been interested in voltage stability or voltage collapse phenomena. The voltage instability is different Com the transient stability in the sense of reactive power mismatch and the long duration time. In this study, we developed efficient tool for analyze and control the dynamic voltage instability. To analize specific condition of dynamic voltage stability, quasi-dynamic simulation method is developed. To provide proper mathmatical model for dynamic voltage stability, generator, SVC, OLTC, induction motor models are introducted. To provide specified dynamic voltage stability, the authors considered to use reactive loss function(${\partial}Q/{\partial}p_L$) as reactive power facility control index. This program was tested and identified its usefulness in real KEPCO system.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.67-77
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• 2020

Traditionally nuclear thermal hydraulic and nuclear safety has relied on numerical simulations to predict the system response of a nuclear power plant either under normal operation or accident condition. However, this approach may sometimes be rather time consuming particularly for design and optimization problems. To expedite the decision-making process data-driven models can be used to deduce the statistical relationships between inputs and outputs rather than solving physics-based models. Compared to the traditional approach, data driven models can provide a fast and cost-effective framework to predict the behavior of highly complex and non-linear systems where otherwise great computational efforts would be required. The objective of this work is to develop an AI algorithm to predict the peak fuel cladding temperature as a metric for the successful implementation of FLEX strategies under extended station black out. To achieve this, the model requires to be conditioned using pre-existing database created using the thermal-hydraulic analysis code, MARS-KS. In the development stage, the model hyper-parameters are tuned and optimized using the talos tool.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.71.2-71.2
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• 2021

Using multi-epoch spectra of active galactic nuclei (AGN) obtained from the Sloan Digital Sky Survey, we identify 16 spectrally variable sources, for which the spectral shapes of broad emission lines significantly vary with a time scale of yrs. Out of them, 3 AGNs are already known as changing-look (CL) AGNs by previous studies. 6 AGNs are newly identified as CL AGNs from our study. A majority of these AGNs are relatively faint and their variability in the continuum is small, which may explain their non-detection in the previous studies. 7 sources are known as binary AGN candidates based on the systematic velocity offset between broad emission lines and narrow emission lines. For those sources and 3 CL AGNs, we find that the peak of broad emission lines had been shifted up to a few thousands km/s for ~10 years, implying that those can be promising candidates for pc-scale binary AGNs or recoiling black holes. We plan to conduct multiwavelength follow-up studies to nail down the physical origin of the velocity shift.

• Asia-Pacific Journal of Business
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• v.15 no.1
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• pp.273-287
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• 2024

Purpose - This study conducts the co-occurrence analysis, one of the social network analysis using global OTA's online reviews and grades in order to understand the experience structure of foreign tourists visiting cutural tourism resources in Jeju, Korea. Design/methodology/approach - For this purpose, this study selects 6 cultural tourism resources in Jeju as the study sites, and collects qualitative review data (noun, adjectives, and verb) and quantitative grade data. Findings - The co-occurrence network analysis between words and grade of market and street shows that the grade of 5 appears the most simultaneous with pork, buy, lot, try, fresh, black, food, price, seafood, local, market, good, street, etc. and the grade of 1 connects with small, dish, better, taste, etc. And the co-occurrence network analysis between words and grade of tradition and folklore shows that the grade of 5 appears the most simultaneous with village, place, museum, visit, time, life, culture, women, diver, use, lot, etc. and the grade of 1 connects with minute, spend, room, recommend, honey, etc. Research implications or originality - The above research results are relevant in order to find out the core experience of foreign tourists using online review and grade generated by foreign tourists and use as the important information to develop the strategies related to the planning and management of cultural tourism resources.

• Korean Journal of Veterinary Service
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• v.41 no.2
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• pp.111-118
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• 2018

This study was carried out to investigate the prevalence of honeybee (Apis mellifera) diseases in Gwangju area. From November 2016 to August 2017, 89 samples were collected from 33 apiculture farms and reverse transcriptase-polymerase chain reaction (RT-PCR), polymerase chain reaction (PCR), and real time PCR were conducted. 14 infectious pathogens, including seven viruses, two bacteria, three fungi, and two parasites, were investigated from random apiculture farms in Gwangju. The percentage of infectious pathogens were as follows: Stonebrood (76.4%), Deformed wing virus (51.7%), Nosema (27.0%) in PCR and RT-PCR. This result indicated that Stonebrood was most prevalent disease in Gwangju area. And we could get similar results from real time PCR. 84.8% of farms have more than two of infectious pathogens. Stonebrood and Deformed wing virus were major diseases in almost all seasons and Black queen cell virus disease was especially prevalent in May.