• The Journal of the Korea Contents Association
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• v.17 no.9
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• pp.375-384
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• 2017

The objective of this study is to suggest problems and complementation of Korean curriculum by comparatively analyzing curriculums of domestic/foreign musical-related departments. In order to compare differences in domestic/foreign curriculums, selecting musical-related departments of domestic colleges with four-year course and 2 or 3-year course, and also five musical-related schools in the US and another five schools in France, the actual lesson status of dance curriculum was researched. In the results, for the development of Korean musical, it would be necessary to reorganize its curriculum. First, the systematic dance curriculum suitable for musical site would be needed. Second, the dance technique lesson suitable for diversified musical expressions should be strengthened. Third, teaching methods for the characterized musical dance would be necessary. Above all, we need effective education method concerned with performance venues. Musical students are facing difficulties in performing acting, singing, and dancing at the same time. In reality, it is even tough to learn a single area among them. For the original Korean-style musical that could be imitated by no one, the systematic curriculum of college is very important.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.527-534
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• 2006

A real-time hybrid method, in which the experimental implementation and the numerical computation of a structure are simultaneously carried out in real-time and combined on-line, has been used as a dynamic testing technique of structure to investigate its dynamic behaviors. In this paper, an experimental hybrid method, which implements the earthquake response control of a building structure with a TLD by using only a TLD as an experimental part, is proposed and is experimentally verified through a shaking table test. In the proposed methodology, the whole building structure with a TLD is divided into the upper TLD and the lower structural parts as experimental and numerical substructures, respectively. At the moment, the control force acting between their interface is measured from the experimental TLD with shear-type load-cell which is mounted on shaking table. Shaking table vibrates the upper experimental TLD with the response calculated from the numerical substructure, which is subjected to the excitations of the measured interface control force at its top story and an earthquake input at its base. The experimental results show that the conventional method, in which both a TLD and a building model are physically manufactured and are tested, can be replaced by the proposed methodology with a simple experimental installation and a good accuracy for evaluating the control performance of a TLD.

• Journal of Dental Anesthesia and Pain Medicine
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• v.21 no.5
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• pp.451-459
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• 2021

Background: Lignocaine with adrenaline is routinely used as a local anesthetic for dental procedures. Adrenaline was added to increase the duration of anesthesia. However, epinephrine containing a local anesthetic solution is not recommended in conditions such as advanced cardiovascular diseases and hyperthyroidism. Recently, ropivacaine has gained popularity as a long-acting anesthetic with superior outcomes. The goal of this study was to assess and compare the effectiveness of 0.75% ropivacaine alone and 2% lignocaine with adrenaline (1:80,000) in the removal of bilateral maxillary wisdom teeth using the posterior superior alveolar nerve block technique. Methods: This was a single-blind, randomized, split-mouth, prospective study assessing 15 systemically sound outpatients who needed bilateral removal of maxillary third molars. We randomly allocated the sides and sequences of ropivacaine and lignocaine with adrenaline administration. We evaluated the efficacy of both anesthetics with regard to the onset of anesthesia, intensity of pain, variation in heart rate, and blood pressure. Results: The onset of anesthesia was faster with lignocaine (138 s) than with ropivacaine (168 s), with insignificant differences (p = 0.001). There was no need for additional local anesthetics in the ropivacaine group, while in the lignocaine with adrenaline group, 2 (13.3%) patients required additional anesthesia. Adequate intraoperative anesthesia was provided by ropivacaine and lignocaine solutions. No significant difference was observed in the perioperative variation in blood pressure and heart rate. Conclusion: Ropivacaine (0.75%) is a safe and an adrenaline-free local anesthetic option for posterior superior alveolar nerve block, which provides adequate intraoperative anesthesia and a stable hemodynamic profile for the removal of the maxillary third molar.

• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.37-51
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• 2021

The pressure drop phenomenon that occurs when the same flow rate is supplied to the gas regulator was analyzed. The regulator moves the position of the piston through the interaction of the force acting on the upper and lower parts of the piston and the spring tension to release the pressure of a specific range in a specific environment as constant pressure, thereby maintaining the pressure. The flow characteristics and pressure control process of the regulator were investigated through a numerical analysis technique as the volume of the fluid inside the regulator changed. As the gap between the piston and the piston seat decreased, the pressure drop increased and the flow velocity increased. It was verified through numerical analysis that the piston was positioned at 0.12mm under the same conditions as the pressure-flow test (inlet pressure 3MPa, outlet pressure 0.8MPa, flow rate 70kg/h).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.1020-1042
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• 2019

Reversible data hiding in encrypted images (RDHEI) provides some real-time cloud applications; i.e. the cloud, acting as a data-hider, automatically embeds timestamp in the encrypted image uploaded by a content owner. Many existing methods of RDHEI only satisfy user privacy in which the data-hider does not know the original image, but leaks owner privacy in which the receiver can obtains the original image by decryption and extraction. In the literature, the method of Zhang et al. is the one providing weak content-owner privacy in which the content-owner and data-hider have to share a data-hiding key. In this paper, we take care of the stronger notion, called strong content-owner privacy, and achieve it by presenting a new reversible data hiding in encrypted images. In the proposed method, image decryption and message extraction are separately controlled by different types of keys, and thus such functionalities are decoupled to solve the privacy problem. At the technique level, the original image is segmented along a Hilbert filling curve. To keep image privacy, segments are transformed into an encrypted image by using random permutation. The encrypted image does not reveal significant information about the original one. Data embedment can be realized by using pixel histogram-style hiding, since this property, can be preserved before or after encryption. The proposed method is a modular method to compile some specific reversible data hiding to those in encrypted image with content owner privacy. Finally, our experimental results show that the image quality is 50.85dB when the averaged payload is 0.12bpp.

• Tribology and Lubricants
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• v.36 no.6
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• pp.371-377
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• 2020

In In this study, we compared the results of a ball bearing life prediction model based on rolling element loads with the results of fatigue life prediction of ball bearings when a stress-based contact fatigue life prediction technique is applied to the ball bearing. We calculate the load acting on each rolling element by the external load of the bearing and apply the result to the Lundberg-Palmgren (LP) theory to calculate ball bearing life based on the rolling element. We also calculate stress-based ball bearing life through contact and fatigue analyses based on contact modeling of the ball and raceway while considering the fatigue test results of AISI 52100 steel. In stress-based life prediction, we use three high-cycle fatigue-determination equations that can predict the fatigue life when multi-axis proportional loads such as rolling-slide contact conditions are applied. These equations are derived from the stress invariant and critical plane methods and the mesoscopic approach. Life expectancy results are compared with those of the LP model. Results of the analysis indicated that the fatigue life was predicted to be lower in the order of the Crossland, Dang Van, and Matake models. Of the three, the Dang Van fatigue model was found to be the closest to the LP life.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.208-222
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• 2021

Managing with the presence of sea ice is the primary challenge in the operation of floating platforms in the Arctic region. It is widely accepted that offshore structures operating in Arctic conditions need station-keeping methods as well as ice management by icebreakers. Dynamic Positioning (DP) is one of the station-keeping methods that can provide mobility and flexibility in marine operations. The presence of sea ice generates complex external forces and moments acting on the vessel, which need to be counteracted by the DP system. In this paper, an icevaning control algorithm is proposed that enables Arctic offshore vessels to perform DP operations. The proposed icevaning control enables each vessel to be oriented toward the direction of the mean environmental force induced by ice drifting so as to improve the operational safety and reduce the overall thruster power consumption by having minimum external disturbances naturally. A mathematical model of an Arctic offshore vessel is summarized for the development of the new icevaning control algorithm. To determine the icevaning action of the Arctic offshore vessel without any measurements and estimation of ice conditions including ice drift, task and null space are defined in the vessel model, and the control law is formulated in the task space. A backstepping technique is utilized to handle the nonlinearity of the Arctic offshore vessel's dynamic model, and the Lyapunov stability theory is applied to guarantee the stability of the proposed icevaning control algorithm. Experiments are conducted in the ice tank of the Korea Research Institute of Ships and Ocean Engineering to demonstrate the feasibility of the proposed approach.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.3
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• pp.158-166
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• 2021

In this paper, a numerical analysis technique using a body force model is investigated to estimate the available net thrust of multi-pod-driven ice-breaking vessels under bollard pull and overload conditions. To employ the body force model in present flow simulations, drag and thrust components acting on the pod unit are calculated by using Propeller Open Water (POW) test data. The available net thrusts according to the direction of operation are evaluated in both bollard pull and overload conditions under deep water. The simulation results are compared with the model test data. The available net thrusts, calculated by the present analysis for ahead operating modes at 3~6 knots which are typical speeds of the target vessel in arctic field, are agreed well with the model test results. It is also found that the present result for astern operating mode appears approximately 6 % larger than the model test result. In addition, the available net thrusts are calculated under the both operating conditions accompanied by shallow water effects, and the main cause of the difference is studied. Based on the result of the present study, it is confirmed that the body force model can be applied to the performance evaluation of multi-pod propulsion system and the main engine selection in early design stage of the vessel.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.2
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• pp.120-134
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• 2023

In this study, hydrodynamic characteristics of dam break flow were investigated by a series of experiments. The experiments were performed in a 2-D rectangular flume with obtaining instantaneous images of dam break flow to capture the free surface elevation, and pressure distributions on vertical wall and bottom of the flume. The initial water depth of the dam break flow was changed into 3 different heights, and the gate opening speed was changed during the experiments to study the effect of the gate speed in the dam break flow. Generation of dam break phenomena could be classified into three stages, i.e., very initial, relatively stable, and wall impact stages. The wall impact stage could be separated into 4 generation phases of wall impinge, run-up, overturning, and touchdown phases based on the deformation of the free surface. The free surface elevation were investigated with various initial water depth and compared with the analytic solutions by Ritter (1892). The pressures acting on the vertical wall and bottom were provided for the whole period of dam break flow varying the initial water depth and gate open speed. The measurement results of the dam break flow was compared with the hydrodynamic characteristics of green water phenomena, and it showed that the dam break flow could overestimate the green water loading based on the estimation suggested by Buchner (2002).

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.841-852
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• 2023

Gas turbines, which are used as generators for frequency regulation of the domestic power system, are increasing in use due to the carbon-neutral policy, quick startup and shutdown, and high thermal efficiency. Since the gas turbine rotates the turbine using high-temperature flame, the turbine inlet temperature is acting as a key factor determining the performance and lifespan of the device. However, since the inlet temperature cannot be directly measured, the temperature calculated by the manufacturer is used or the temperature predicted based on field experience is applied, which makes it difficult to operate and maintain the gas turbine in a stable manner. In this study, we present a model that can predict the inlet temperature of a reheat gas turbine based on Deep Neural Network (DNN), which is widely used in artificial neural networks, and verify the performance of the proposed DNN based on actual data.