• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.29-39
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• 2017

In this research, thermal design data such as heat transfer coefficient on the wall surface required for ventilation system design which is to prevent the temperature rise in the underground utility tunnel that three sides are adjoined with the ground was investigated in numerical analalysis. The numerical model has been devised including the tunnel lining of the underground utility tunnel in order to take account for the heat transfer in the tunnel walls. The air temperature in the tunnel, wall temperature, and the heating value through the wall based on heating value(117~468 kW/km) of the power cable installed in the tunnel and the wind speed in the tunnel(0.5~4.0 m/s) were calculated by CFD simulation. In addition, the wall heat transfer coefficient was computed from the results analysis, and the limit distance used to keep the air temperature in the tunnel stable was examined through the research. The convective heat transfer coefficient at the wall surface shows unstable pattern at the inlet area. However, it converges to a constant value beyond approximately 100 meter. The tunnel wall heat transfer coefficient is $3.1{\sim}9.16W/m^2^{\circ}C$ depending on the wind speed, and following is the dimensionless number:$Nu=1.081Re^{0.4927}({\mu}/{\mu}_w)^{0.14}$. This study has suggested the prediction model of temperature in the tunnel based on the thermal resistance analysis technique, and it is appraised that deviation can be used in the range of 3% estimation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.129-137
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• 2016

In the present study we verified performance of feed-forward control algorithm using short term prediction of ship motion information by taking advantage of developed numerical simulation model of FPSO motion. Up until now, various studies have been conducted about thrust control and allocation for dynamic positioning systems maintaining positions of ships or marine structures in diverse sea environmental conditions. In the existing studies, however, the dynamic positioning systems consist of only feedback control gains using a motion of vessel derived from environmental loads such as current, wind and wave. This study addresses dynamic positioning systems which have feedforward control gain derived from forecasted value of a motion of vessel occurred by current, wind and wave force. In this study, the future motion of vessel is forecasted via Brown's Exponential Smoothing after calculating the vessel motion via a selected mathematical model, and the control force for maintaining the position and heading angle of a vessel is decided by the feedback controller and the feedforward controller using PID theory and forecasted vessel motion respectively. For the allocation of thrusts, the Lagrange Multiplier Method is exploited. By constructing a simulation code for a dynamic positioning system of FPSO, the performance of feedforward control system which has feedback controller and feedforward controller was assessed. According to the result of this study, in case of using feedforward control system, it shows smaller maximum thrust power than using conventional feedback control system.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.173-180
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• 2015

A passive type of fence security system was developed, which was based on electric charge detection technique. The implemented fence security system was installed at outskirts of greenhouse laboratory in the University of Seoul. The purpose of this research is to minimize false alarms by analyzing environmental noise. The existing system determines the intrusion alarm by analyzing the power of amplified signal, but the alarm was seriously affected by natural strong wind and heavy rainfall. The SAU(Signal Analysis Unit) sends input signals to remote server which displays intrusion alarm and stores all the information in database. The environmental noise such as temperature, humidity and wind speed was separately gathered to analyze a correlation with input signal. The input signal was analyzed for frequency characteristic using FFT(Fast Fourier Transform) and the algorithm that differentiate between intrusion alarm and environmental noise signal is improved. The proposed algorithm is applied for the site for one month as the same as the existing algorithm and the false alarm data was gathered and analyzed. The false alarm number was decreased by 98% after new algorithm was applied to the fence. The proposed algorithm improved the reliability at the field regarding environmental noise signal.

• Korean Journal of Remote Sensing
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• v.32 no.6
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• pp.603-616
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• 2016

In this study, the effects of differential heating by land-use types on flow and air temperature at an Seoul Automated Synoptic Observing Systems (ASOS) located at Songwol-dong, Jongno-gu, Seoul was analyzed. For this, a computation fluid dynamics (CFD) model was coupled to the local data assimilation and prediction system (LDAPS) for reflecting the local meteorological characteristics at the boundaries of the CFD model domain. Time variation of temperatures on solid surfaces was calculated using observation data at El-Oued, Algeria of which latitude is similar to that of the target area. Considering land-use type and shadow, surface temperatures were prescribed in the LDAPS-CFD coupled model. The LDAPS overestimated wind speeds and underestimated air temperature compared to the observations. However, a coupled LDAPS-CFD model relatively well reproduced the observed wind speeds and air temperature, considering complicated flows and surface temperatures in the urban area. In the morning when the easterly was dominant around the target area, both the LDAPS and coupled LDAPS-CFD model underestimated the observed temperatures at the Seoul ASOS. This is because the Kyunghee Palace located at the upwind region was composed of green area and its surface temperature was relatively low. However, in the afternoon when the southeasterly was dominant, the LDAPS still underestimated, on the while, the coupled LDAPS-CFD model well reproduced the observed temperatures at the Seoul ASOS by considering the building-surface heating.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.316-329
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• 2012

In this paper, optimum design process of ICP (Inductively Coupled Plasma) torch, which has been used widely in aerospace application, such as supersonic plasma wind tunnel, is presented. For this purpose, the behaviors of equivalent circuit parameters (equivalent resistance and inductance, coupling efficiency) were investigated according to the variations of torch design parameters (frequency, $f$, confinement tube radius, $R$ and coil turn numbers, $N$) in the basis of analytical and numerical MHD (Magneto Hydro-Dynamics) models combined with electrical circuit theory. From the results, it is found that equivalent resistance is increased with the increase of $f$ values but vice versa for equivalent inductance. For elevated values of $R$ and $N$, however, both parameters tend to increase. Based on these observations, ICP torch with a power level of 10 kW can be optimized at the design ranges of $f$=4~6 MHz, $R$=17~25 mm and $N$=3~4 to maximize the electrical coupling efficiency, which is the ratio of equivalent resistance to equivalent inductance.

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.99-114
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• 2018

Saekdong is a unique Korean fabric that has been used since ancient times, and it is woven with the plain or satin weave so that vertical stripes appear by various colored warp threads of equal spacing. Saekdong means pleasure, joy, serenity, heavenly blessing, spirituality, wind, and abundance, expressing the optimistic and positive sentiment of Korea's forefathers. This study investigated how ancient Saekdong occurred with meanings. As a research method, this study used literature review and surfing newspapers and photographs, museum and internet search, even from other fields such as earthenware, bronze, and traditional dance. We collected Saekdong and the lifestyles of ethnic Koreans living in China, investigated the Asuka culture of Japan, and the tomb murals of Takamatsu-Chong, which are Baekje and Goguryeo settlement areas. The results are as follows: First, it expresses happy occasion, pleasure, and joy, and expresses a desire for good things to be repeated and lasting. Second, it symbolizes simple beauty, order, equality and harmony of many tribes. Third, Saekdong is life and power which represent a sacred, heavenly, mysterious bird. Fourth, it symbolizes abundance and wealth, rain, wind or fields. Finally, this study showed the brilliance and pride of Korean hanbok through Saekdong. The significance of this study is to examine the symbolism and inherent aesthetic characteristics of Saekdong and to show the unique value and spiritual heritage of the Korean people.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.208-213
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• 2013

The suitability of the site criteria is a basic requirement for securing safety of nuclear power plants. The suitability should be confirmed through the estimation of environmental radiation effects at the exclusion area boundary under the severe weather conditions. In this study, field tracer experiments over short range of 1 km radius under severe weather conditions were conducted at flat area in Daejeon. Severe weather conditions are represented with stable atmospheric condition and low wind speed. In general, the condition is appeared at clean night time with weak wind. The analysis of the measured distribution of the released tracer gas shows two big differences between the results of the past experiments conducted under the favorable weather conditions. One is the difficulty of finding the typical distribution of the released tracer gas with peak concentration in the downwind direction. The other one is the appearance of the contour of the concentration of tracer gas at several hundred meters even though the gas released at 10 m height over the ground.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.217-228
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• 2021

The purpose of this study is to analyze drum performance techniques, focusing on the representative artists of funk music, who had a revival starting in the 1970s. The purpose of this study is to analyze the creativity shown in David Garibaldi's playing technique, which had a great influence on drum majors with his funk drum playing technique. As a research method, 'James Brown', 'Earth, Wind & Fire' and 'Tower of Power' with David Garibaldi as drummer were selected as representative bands. For the study period, the drum performance was examined by selecting two representative songs from among the songs released between 1965 and 1975, when the development of the corresponding funk music began. David Garibaldi's creative performance in this study is as follows. First, we tried to create a new rhythm in the form of changing the beat or resting the beat out of the frame of contemporary drum performance. Second, the 'Paradiddle', 'Accent', and 'Swiss Army triplet' rudiment techniques were applied to the entire drum kit, bringing innovation to the rhythm. Third, the samba pattern of Latin rhythm and the form of 'Afro-Cuban' were grafted onto funk music. Fourth, the idea of Unison Rhythm obtained from the structure of Latin music was applied to funk music. Based on this study, it is hoped that research on drum performance techniques of various genres will be conducted.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.65-75
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• 2018

The wind energy produced at night is being discarded because of the excess power generated at night compared to daytime. To solve this problem, In this study, we analyzed the evaluation contents for evaluation of domestic and overseas water electrolysis systems and drew contents for safety performance contents test of the water electrolysis system based on the evaluation contents. The test contents produced the efficiency measurement test, the hydrogen generated pressure test, and the hydrogen purity test. And the safety performance evaluation of the alkaline water electrolysis system of $5Nm^3/hr$ was performed based on the results. As a result, the hydrogen generation was calculated as $5.10Nm^3/hr$ and the stack efficiency was $4.97kWh/Nm^3$. The purity of the hydrogen generated was 99.993% and it was confirmed that it produced high purity hydrogen. I think will help us assess and build safety performance of water electrolysis systems in the future.

• (The)Study of the Eastern Classic
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• no.32
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• pp.245-278
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• 2008

The purpose of this paper is to create an inter-religious dialogue between the Western Christian concept of the spirit and Eastern ch'i philosophy within the category of panentheism. The Hebrew term ruah means 'moving air' and 'wind' which derive from the particular experience of the ancient Hebrew people living in the desert. The Greek pnuema also means 'life' and 'wind' which denote the natural power. Both ruah and pneuma consist of the main idea of the spirit exploring the symbol of relationality of the divine in Western tradition. Eastern ch'i philosophy indicates a vital force for keeping the body and soul alive, which is unconscious and spontaneous. Ch'i as a vital force constitutes cosmogony and cosmology with the constant movement of yin and yang. Yin and Yang as representing earth and heaven are dynamic breaths, blending harmoniously to become all existence. The ethical implication of the inter-religious dialogue between the spirit and ch'i would be the integration and interconnection of heaven, earth, and human beings. The dialogue suggests becoming one body with nature and human community through embodying the non-dualistic spirit of life. The inter-relationality means that since all modalities of existence are made of the cosmic life, human beings are part of the divine cosmic process. This is related to degree of spirituality in the entire chain of being: rocks, trees, animals, humans, and goods represent different levels of spirituality based on the varying composition of the spirit and ch'i. All beings that internally embody with the spirit and ch'i are organically inter-connected, and they are integral part of a continuous process of transformation of life towards holistic liberation of human and nature community.