• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.5 no.1
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• pp.54-69
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• 1994

The purpose of present study was to develop the Korean Version of Luria-Nebraska Neuropsychological Battery for Children(LNNB-C), to examine the reliability of it, and to establish the norms for determining the probability of brain damage. The normative group used to standardize the Korean version of LNNB-C was composed of 147 children between the age of 8 and 12(body 74, girl 73). The clinical group consisted of 19 brain damaged, 16 ADHD, and 16 psychiatric controls. The inter-scorer reliability was 96.3%, indicating that the stability of the scoring system for the Korean version of LNNB-C is good. The reliability coefficients(Cronbach's ${\alpha}$) of LNNB-C scales were ranged .51 to .91, which are similar to those of original LNNB-C. To establish the norms for detecting brain damage, the means and standard deviations for normative group were used to calculate T-scores for each scale. To determine a critical level that could successfully predict a normal child's average score at a given age, first the average score of normative group was calculated, and this score was then entered a regression equation with age to predict the average(baseline) acore. Finally, some issues on constructing the Korean version of LNNB-C and the cultural differences between Korean and American children in performing LNNB-C were discussed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.4
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• pp.313-327
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• 2008

Thermo-mechanical coupled behavior of an underground structure during a fire accident have not been fully understood yet. Moreover, when such a thermo-mechanical coupled behavior is not considered in numerical analyses based on conventional heat transfer theory, fire-induced damage zone in an underground structure can be considerably underestimated. This study aims to develop a FEM-based numerical technique to simulate the thermo-mechanical coupled behavior of an underground structure in a fire accident. Especially, an element elimination model is newly proposed to simulate fire-induced structural loss together with a convective boundary condition. In the proposed model, an element where the maximum temperature calculated from heat transfer analysis is over a prescribed critical temperature is eliminated. Then, the proposed numerical technique is verified by comparing numerical results with experimental results from real fire model tests. From a series of parametric studies, the key parameters such as critical temperature, element size and temperature-dependent convection coefficients are optimized for the RABT and the RWS fire scenarios.

• Journal of the Korean Applied Science and Technology
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• v.41 no.3
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• pp.543-554
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• 2024

In this study, the anti-inflammatory, anti-bacterial and anti-oxidative activities of subcritical water extract from Chamaecyparis obtusa leaves was compared with hot water extract. The yield of subcritical water extract (165℃ and 180℃, 80 bar) was 39.4~48.5%, higher than 31.5% of hot water extract. In the anti-inflammatory tests using lipopolysaccaride (LPS)-induced RAW264.7 macrophages, the subcritical water extract concentration-dependently inhibited production of nitric oxide (NO) without causing cell toxicity. Upon the anti-bacterial studies using Cutibacterium acnes and Staphylococcus epidermidis, subcritical water extract showed the stronger activity than hot water extract. In addition, DPPH and ABTS cation radical scavenging activity experiments showed that the radical scavenging activity of subcritical water extract was similar to that of hot water extract. Moreover, in the study of cell protection effect using HaCaT keratinocytes damaged by hydrogen peroxide (H₂O₂), the subcritical water extract (165℃, 80 bar) indicated protective effect against oxidative stress. These results suggested that the subcritical water extract of C. obtusa leaves as natural ingredients could be used as anti-inflammatory, anti-bacterial and anti-oxidative ingredients in cosmetic formulations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1387-1395
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• 2013

When the center of mass of a railway wheel is not aligned with the geometrical center of the wheel axis, wheel unbalance occurs. If a railway vehicle runs without removing the wheel unbalance, vibrations will be produced. This will also cause wear and damage of the axle bearing. In this study, dynamic analysis of a railway vehicle with wheel unbalance was conducted to examine the reduction in critical speed and the resonance of the car-body and the effect on the magnitude of wheel unbalance was examined. In addition, the calculation of the car-body vibration owing to static and dynamic unbalance in the railway wheel shows that two-plane balancing is necessary.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.5
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• pp.94-102
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• 2007

In de-noising, it is wellknown that wavelet-thresholding algorithm shows near-optimal performances in the minimax sense. However, the wavelet-thresholding algorithm is difficult in realization it on hardware, such as FPGA, because of wavelet function complexity. In this paper, we present a new do-noising technique with the binary tree structured filter bank, which is based on the signal power ratio of each subbands to the total signal power. And we realize it on FPGA. For simple realization, the filter banks are designed by Hadamard transform coefficients. The simulation and hardware experimental results show that the performance of the proposed method is similar with that of soft thresholding de-noising algorithm based on wavelets, nevertheless it is simple.

• Journal of Broadcast Engineering
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• v.7 no.4
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• pp.368-375
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• 2002

In this paper, we apply multiresolution wavelet transform for the digital image watermarking. For better result, we insert watermark into the images and set a proper weighting factor for each subband based on HVS model. With proposed algorithm, we confirm that the image quality is satisfactory and this method outperforms the previous methods against image compression and cropping.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.41-46
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• 2011

The tire damage classification method is researched by periodicity detection of ultrasonic envelope signals to occur at the driving vehicle tire. Because periodic signals is generated by rotations of the damaged tire, it should convert to pulse for using the density function. After time intervals of pulses are represented by the density function, the dominant periodicity is detected. The threshold to make a pulse is calculated by moving average of envelope signals. The result of time density function in case of one damage material, the first peak's time is equals to tire's rotation period, 162ms and 102ms, about the speed of 50km/h and 80km/h. In case of more than one damage material, the sum of each peak's time is equals to tire's rotation period about the speed.

• Journal of the Korean Society for Nondestructive Testing
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• v.17 no.1
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• pp.1-10
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• 1997

In this paper, the effects of temperature change (low and high temperature) on the impact damages of CFRP laminates was experimentally studied. Composite laminates used for this experiment are CF/epoxy orthotropic laminated plates, which have two-interfaces $[0^{\circ}\;_6/90^{\circ}\;_6]s$ and $[0^{\circ}\;_4/90^{\circ}\;_4]s$. And CF/PEEK orthotropic laminated plates, which have two-interfaces $[0^{\circ}\;_4/90^{\circ}\;_4]s$. And, this study aims experimentally to present the interrelations between the impact energy vs. impact damages (i.e. delamination area and matrix crack) of CFRP laminates (CF/epoxy, CF/PEEK) subjected to FOD(foreign object damage) under low and high temperatures. A steel ball launched by the air gun collides against CFRP laminates to generate impact damages.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.1
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• pp.33-40
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• 2021

In recent years, many construction projects become large and complicated, and construction accidents also steadily increase, which grows interest in the safety and maintenance during construction. Many of the construction accidents are related to temporary construction and structures, but the safety evaluation and management during construction are unclear and indefinite due to the short operating period and continuous change in the formation of the temporary structure. The system support, which is one of the temporary structures to support the pouring load of concrete, was proposed to easily install and dismantle members with connection parts pre-manufactured. The use of the system support is increasing to improve the safety of the temporary structure during construction. However, the system support, which consists of multiple members, still has uncertainties in connectivity between members and supports of vertical members. Therefore, this study analyzed the structure, load, and accident cases of the system support to define the damage scenarios for member connection, support condition, and lateral displacement. The decrease rate of the critical load was analyzed according to the damage scenarios based on the defined unit structure of the system support. In addition, this study provided vulnerable members for each damage scenario, which could induce instability of the temporary structures during design, construction, and operation of the structure.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.291-296
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• 2015

The tire damage classification method is researched on the periodicity detection of ramdomness ultrasonic signals to occur at the driving vehicle tire. Setting method of adaptive threshold is proposed in order to valid pulse detection by tire damage in ultrasonic noise on the road and used low pass filter for decrease signal ramdomness as preprocessing. Time interval of detected pulse is setted the density function depend on the vehicle's speed and the method of tire damage detection is proposed that measuring the first peak's time of time density function.The result of time density function in case of one damage material, the first peak's time is measured within the error limit of tire's rotation period, 169.8ms and 97.9ms and 81.8ms, about the speed of 50km/h and 80km/h and 100km/h. In case of more than one damage material, the sum of each peak's time is measured within the error limit of tire's rotation period about the speed.