• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.1-7
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• 2010

The soil nailing method have been developed on the basis of experimental works as well as theoretical backgrounds. As for the experimental research works, most of the data have been measured during the application of load in service. However, not only the soil-nailed structure behavior in service but also the failure behavior of the structure are the major concerns to evaluate and even establish a design method of soil-nailed walls. In this paper for the apprehension of behavior in the soil-nailed structure which the front of nail is connected, a relatively large-scale experiment was carried out to figure out the failure behavior of soil-nailed wall. A number of data have been acquired and analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2343-2350
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• 2013

The wave height distributions in front of a vertically perforated wall structures for obliquely incident uni-directional irregular waves are mainly investigated by using 3D hydraulic experiments. The difference and similarity of wave propagation along the plain and perforated wall structures are investigated and particularly the effects of side walls in chamber and relative chamber width are analyzed. This study shows that the wave height distribution patterns for normalized wave heights in front of structure is significantly different between the plain and perforated wall structures, and the side wall in the chamber suppresses the growth of waves.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.6
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• pp.138-144
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• 2010

If the vibration is occurred in a large-sized bus roof, it makes people annoying and complaining the quality of a large-sized bus. So in design stage, it must be considered. To assess vibration at the roof which is equipped with air conditioner in design stage, finite element model is constructed. Computer simulation analysis and experimental method are performed. The dynamic characteristics of the large-sized bus are found by using eigenvalue method. It is related with dynamic behavior. The running conditions of a large-sized bus are velocity and road condition which followed experimental conditions. And the frequency response of a large-sized bus is well correlated with analysis result. Modal participation method is used for finding major modes at each peak. Using this method, we found that front and rear suspension system, engine mounting system and roof structure are the major reasons of the roof vibration. To reduce vibration level of roof in a large-sized bus, spring stiffness of front and rear suspension system, spring stiffness of engine mounting system and roof structure are properly combined. From this study, the vibration characteristics of the roof structure of a large-sized bus can be to a satisfactory level.

• Smart Structures and Systems
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• v.26 no.5
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• pp.545-558
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• 2020

A design method of a Multiple Tuned Mass Damper (MTMD) system is presented for wind induced vibration control of a cable-supported roof structure. Modal contribution analysis is carried out to determine the dominating modes of the structure for the MTMD design. Two MTMD systems are developed for two most dominating modes. Each MTMD system is composed of multiple TMDs with small masses spread at multiple locations with large responses in the corresponding mode. Frequencies of TMDs are distributed uniformly within a range around the dominating frequencies of the roof structure to enhance the robustness of the MTMD system against uncertainties of structural frequencies. Parameter optimizations are carried out by minimizing objective functions regarding the structural responses, TMD strokes, robustness and mass cost. Two optimization approaches are used: Single Objective Approach (SOA) using Sequential Quadratic Programming (SQP) with multi-start method and Multi-Objective Approach (MOA) using Non-dominated Sorting Genetic Algorithm-II (NSGA-II). The computation efficiency of the MOA is found to be superior to the SOA with consistent optimization results. A Pareto optimal front is obtained regarding the control performance and the total weight of the TMDs, from which several specific design options are proposed. The final design may be selected based on the Pareto optimal front and other engineering factors.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.3
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• pp.68-75
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• 2008

The three-dimensional structure of detonation wave propagating in a circular tube was investigated using a parallel computational code developed previously. A series of parametric study for a circular tube of a fixed diameter gave the formation mechanism of the detonation cell structures depending on pre-exponential factor, k. The unsteady results in three-dimension showed the mechanisms of two, three and four cell mode of detonation wave front structures. The detonation cell number was increased but cell width and length were decreased with increased pre-exponential factor k. In the all multi-cell mode, the detonation wave structure and smoked-foil records on the wall are made by the moving of transverse waves. The detonation wave front structures have the regular polygon and windmill shapes periodically.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.679-687
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• 2019

This paper presents the autonomous swimming technology developed for an Autonomous Underwater Vehicle (AUV) operating in the underwater jacket structure environment. To prevent the position divergence of the inertial navigation system constructed for the primary navigation solution for the vehicle, we've developed kinds of marker-recognition based underwater localization methods using both of optical and acoustic cameras. However, these two methods all require the artificial markers to be located near to the cameras mounted on the vehicle. Therefore, in the case of the vehicle far away from the structure where the markers are usually mounted on, we may need alternative position-aiding solution to guarantee the navigation accuracy. For this purpose, we develop a sonar image processing based underwater localization method using a Forward Looking Sonar (FLS) mounted in front of the vehicle. The primary purpose of this FLS is to detect the obstacles in front of the vehicle. According to the detected obstacle(s), we apply an Occupancy Grid Map (OGM) based path planning algorithm to derive an obstacle collision-free reference path. Experimental studies are carried out in the water tank and also in the Pohang Yeongilman port sea environment to demonstrate the effectiveness of the proposed autonomous swimming technology.

• Journal of architectural history
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• v.29 no.2
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• pp.39-52
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• 2020

Seonjeong-jeon, the semi-great hall in Changdeok Palace, was constructed in a highly formal and conservative style and accommodated official ceremonies. However, the contemporary modification of the building has distorted or eliminated features including the two side doors on the front, the floor coverings, and the throne base (Jwa-tap) that consisted the most significant part of the throne. Seonjeong-jeon originally had three doors that stood between each pair of columns on the front side, respectively. The courtiers accessed the building through the side doors, while the central door was exclusively designated for the king. However, the renovation in 1999 ignored the political context of the architectural form of the building and changed the side doors into windows, damaging the traditional structure inherited from the early Joseon Dynasty. Although the building currently has traditional wooden floor structure (Woomul-maru), it was originally covered with square brick tiles (Bang-jeon) before the Japanese occupation, following the customs of early Joseon Dynasty. The throne was placed to the north of the central door and consisted of the throne base and a decorative roof (Dang-ga). A canvas (Jang-ja), which featured the royal symbolic painting of Sun, Moon, and Five Peaks, was also installed between the two columns that connected the base and the roof. Nevertheless, only the columns and the blank canvas remain nowadays after the removal of the base.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.480-484
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• 2006

We propose a new PDP cell structure named DIDE (Dual Ignition Discharge Electrodes) structure with a long electrode gap to realize a high luminous efficacy. Suggested DIDE structure basically has a long electrode gap $(200{\mu}m{\sim}400{\mu}m)$, nevertheless, because of auxiliary electrodes formed on the front panel, can be driven at relatively low voltage. The discharge characteristic of DIDE structure was much different from that of conventional structure, which was analyzed by IR emission images using IICCD (Image Intensified Charge Coupled Device). The study can explain some particular characteristics of DIDE structure. As a result, the long electrode gap and low voltage effect can be expected in DIDE structure, and a very high luminous efficacy of 7.5 lm/W has been achieved in monochrome green test panel adopting the new cell structure with Ne-Xe (12%) mixture at 400 torr.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.101-107
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• 2004

Recently the objective of vehicle design was focused on the crash safety and the energy saving. For the energy saving vehicle structures must be light weight, but for the crash safety some energy absorbing elements must be added. In this paper hybrid structure which consists of a steel and a FRP was studied on the energy absorption characteristics under the impact load by finite element method. Test results of the other researchers were compared with that of computer simulation on this simple hybrid structure. Side rail of vehicle front structure was replaced with hybrid materials for the application of the vehicle structure. 35mph frontal crash simulation was performed with hybrid structure and with conventional steel structure. By the adoption of hybrid structure, the improvement of energy absorption characteristics and reduction of weight was observed under the frontal crash simulation.

• (The) Research of the performance art and culture
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• no.39
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• pp.701-748
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• 2019

Gwanak-yeongsanhoesang, called as Samhyeon-yeongsanhoesang or Pyojeongmanbangjigok, is played by the musical instrumental organization, Samhyeonyukgak or by a large scale wind ensemble added Sogeum and Ajaeng. This study aims to analyze the structure and form of Piri melody which plays major melody of Sangnyeongsan in Gwanak-yeongsanhoesang, and to examine the relationship between Piri melody and Daegeum yeoneum grasping the structure and function of yeoneum. In Sangnyeongsan of Gwanak-yeongsanhoesang, the criterion for grouping the phrases of Piri melody is yeoneum. Especially, Daegeum yeoneum carries out the function of finishing the phrase of Piri playing the major melody by ornamenting or extending it, and presenting the motives or motive elements of the next phrase while Piri rests. The types of a, b, g, and i in the various shapes of the minimum melodic fragment of Piri are important motive elements that constitute a phrase of Piri melody. Especially, main motive a-type (仲→無) contrasts with b type (林→潢) which forms a strong tension by transposing 2 degrees upward. In addition, a-type gradually descends towards the end of music by changing to g-type (仲→林) or to i-type (太→林) which is 3 degrees below, which is related to the gradual descent cadence of Korean traditional music. A phrase of Piri melody of Sangnyeongsan in Gwanak-yeongsanhoesang consists of a combination of the types a, b, g, i, and cadence (x-type), and each phrase is structured in the repeating tension-relaxation. Looking at the structure of Piri phrases by similar types, each phrase has a logical variation structure through the methods such as omission and addition of notes, and crossing of melodies. The shape of the minimum melodic fragment of Daegeum yeoneum can be divided into a back-yeoneum of a~b types and a front-yeoneum of x1~x3. The x-types ornament Jungnyeo (仲), the cadence tone of Piri melody or are simply used as the extending back-yeoneum, and types a and b have the function of a front-yeoneum that prepares the beginning of the next phrase of Piri melody. The combination types of the minimum melodic fragment of Daegeum yeoneum appear mostly as the shape of back-yeoneum + front-yeoneum. In addition, the front-yeoneum of the type a and b appears independently without back-yeoneum, and the x3 type has a shape of the back-yeoneum without the front-yeoneum. Looking at the structure of Daegeum yeoneum by similar types, it can be seen that Daegeum yeoneum is also composed of a variation structure of omission and addition of notes like Piri melody.