• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.94-101
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• 2015

This paper presents findings on the second-order sliding-mode controller for a nuclear research reactor. Sliding-mode controllers for nuclear reactors have been used for some time, but higher-order sliding-mode controllers have the added advantage of reduced chattering. The nonlinear model of Pakistan Research Reactor-1 has been used for higherorder sliding-mode controller design and performance evaluation. The reactor core is simulated based on point kinetics equations and one delayed neutron groups. The model assumes feedback from lumped fuel and coolant temperatures. The effect of xenon concentration is also considered. The employed method is easy to implement in practical applications, and the second-order sliding-mode control exhibits the desired dynamic properties during the entire output-tracking process. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness, and stability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.61-65
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• 2001

The conventional tracking testing as IEC-60587 is widely used in surface aging measurement of outdoor insulator because those testing can carry out very short time in Lab-testing. Also IEC-60587 testing is able to offer the standard judgement of relative degradation level of outdoor HV machine/system. Therefore it is very useful method compare to previous conventional tracking testing method and effective Lab-testing method. But surface discharges(SD) have very complex characteristics of discharge pattern so it is required estimation research to development of precise analysis method. In recent, the study of IRR-camera is carrying out discover of temperature of power equipment through condition diagnosis and system development of degradation diagnosis. In this study, SD occurred from procelain insulator, used 22.9[KV] distribution, is measured with partial temperature distribution in real time, the degradation grade of SD is analyzed through produced patterns in SD concentration according to applied time.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1210-1212
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• 1997

This study describes the influence of the size of the median particles of alumina trihydrated(ATH) filler on the tracking resistance, tensile properties, dielectric properties and water immersion properties of EPDM rubber. A fixed 100pph concentration of the filler of A TH was used for all particle sizes from 0.7 to $20{\mu}m$. It is shown that tracking and erosion resistance decrease with increasing particle size, whereas tensile properties and dielectric properties are improved with increasing particle size of ATH.

• Korean Institute of Interior Design Journal
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• v.21 no.2
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• pp.92-100
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• 2012

This study was to examine the pattern of visual interpretation in the process of eye-tracking. I categorized the subjects' observation inclination for analysis so that I could find out which element the user observing the space concentrated and explored. First, for 2 minutes of observation, there occurred 171 times of eye-fixations and 9.8 times of observation frequency on average, which showed that the subject, through this observing fixation, spent 44.5% of the entire time performing the visual activity in order to acquire the "visual understanding" of the lobby-space. Second, I found out that there was a consistent observation type as the time passed. I could categorize the subjects observing the space into 6 concentrating types and 3 discontinuing ones of observation types, which category can be utilized as data for analyzing the subjects' characteristics at space-observation. Third, the type, which was so intensive as to get the visual understanding on the space, was mostly of the case that (1) the subject had a kind of high degree of observation type, exploring the space, again having high degree of the observation type [Type A], (2) the subject repeated the concentration from the early part to the latter [Type C], which can be considered to be the observation type generally shared. Fourth, in the case of observing the space, 45.8% of the subjects showed a high rate of concentration at the time of starting the observation and in less than two minutes. The subjects of type A can be considered to understand the space visually by distinctively repeating the concentration and exploration.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.74.3-74
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• 2001

This paper proposes a nonlinear adaptive controller based on back-stepping method for tracking reference substrate concentration by manipulating dilution rate in a continuous baker´s yeast cultivating process in stirred tank bioreactor. Control law is obtained from Lyapunov control function to ensure asymptotical stability of the system. The Haldane model for the specific growth rate depending on only substrate concentration is used in this paper. Due to the uncertainty of specific growth rate, it has been modified as a function including the unknown parameter with known bounded values. The substrate concentration in the bioreactor and feed line are measured. The deviation from the reference is observed when the external disturbance such as the change of the feed is introduced to the system ...

• Journal of Korea Multimedia Society
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• v.24 no.11
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• pp.1580-1587
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• 2021

Currently, the development and sale of various emoticons has given users a wider range of choices, but a systematic and specific approach to the recognition and use of emoticons by actual users is lacking. Therefore, this study tried to investigate the subjective perception and visual attention concentration of actual users on negative emotional expression emoticons through a survey and eye tracking experiment. First, as a result of subjective recognition analysis, it was found that emoticons are frequently used because their appearance is important, and they can express various emotions in a fun and interesting way. In particular, it was found that emoticons that express negative emotions are often used because they can indirectly express negative emotions through various and concretely expressed visual elements. Next, as a result of the eye tracking experiment, it was found that the negative emotional expression emoticons focused on the large elements that visually emphasized or emphasized the emotional expression elements, and it was found that the focus was not only on the facial expression but also on the physical behavioral responses and language of expression of emotions. These results will be used as basic data to understand users' perceptions and utilization of the diversified emoticons. In addition, for the long-term growth and activation of the emoticon industry market in the future, continuous research should be conducted to understand the various emotions of real users and to develop differentiated emoticons that can maximize the empathy effect appropriate to the situation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.49-57
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• 2022

The government is making great efforts to prevent crimes such as missing children by using public CCTVs. However, there is a shortage of operating manpower, weakening of concentration due to long-term concentration, and difficulty in tracking. In addition, applying real-time object search, re-identification, and tracking through a deep learning algorithm showed a phenomenon of increased parameters and insufficient memory for speed reduction due to complex network analysis. In this paper, we designed the network to improve speed and save memory through the application of Yolo v4, which can recognize real-time objects, and the application of Batch and TensorRT technology. In this thesis, based on the research on these advanced algorithms, OSNet re-ranking and K-reciprocal nearest neighbor for re-identification, Jaccard distance dissimilarity measurement algorithm for correlation, etc. are developed and used in the solution of CCTV national safety identification and tracking system. As a result, we propose a solution that can track objects by recognizing and re-identification objects in real-time within situation of a Korean public multi-CCTV environment through a set of algorithm combinations.

• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.80-88
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• 2011

Heliostat in the tower type solar thermal power plant is a sun tracking mirror system to reflect the solar energy to the receiver and the optical performance of it affects to the efficiency of whole power plant most significantly. Thus a solid understanding of heliostat's energy concentration characteristics is the most important step in designing of the heliostat field and the whole power plant. The work presented here is the analysis of energy concentration characteristics of heliostat used in 200kW solar thermal power plant, where the receiver located at 43m high in tower has $2{\times}2$m rectangular shape. The heliostat reflective surface is formed by 4 of $1{\times}1$m flat plate mirror facet and the mirror facet is mounted on the spherical frame. The direct normal incident radiation models in vernal equinox, summer solstice, autumnal equinox and winter solstice are first derived from the actually measured data. Then the intercept ratio, heat flux distribution and total energy collected at the receiver for the heliostats located in the various places of the heliostat field are investigated. Finally the effect of mirror facet installation error on the optical performance of the heliostat is analyzed.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.293-297
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• 2010

Next generation concentrating photovoltaic technologies could have a large-scale impact on world electricity production once they will become economically attractive and grid parity will be reached. Multi-junction solar cells will be characterised by a high value of the cell economical performance index if the cells were able to operate at high concentration level. Concentrating the sunlight by optical devices like lenses or mirrors reduces the area of expensive solar cells or modules, and, moreover, increases their efficiency. Accurate and reliable tracking is an important issue to maintain high the CPV system output power. Further, for high concentration CPV systems, the actual tracker cost is about 20% of the total CPV system cost. In this paper high-concentration is defined as systems using concentration ratios well above 100 times the one sun intensity and trackerlss CPV system studied. Using sphericalness lens and parallel MJ cell connection method were suggested and achieved experiment on a clear day in summer. Development of these high performance multi-junction CPV module promises to accelerate growth in photovoltaic power generation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.2
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• pp.185-192
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• 1996

In order to simulate the coastal dispersion effectively, hybrid concept of operator split Eulerian-lagrangian concentration model and random-walk particle tracking model are developed. Especially the random-walk model is adequate for region with steep slope of concentration. According to model tests, it agrees perfectly with analytical solution on around the source point for therefore. ▽C $\geq$ 0.005, meanwhile it shows poor results for ▽C$\leq$0.002. trial modeling for real situation therefore, random-walk model is applied for near field henceforth Eulerian-Lagrangian concentration model is adoped for whole domain so that overall performance and accuracy can be achieved by using developed hybrid model.