• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.6
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• pp.112-122
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• 2009

In this paper, we present a novel space-frequency adaptive image restoration approach using vaguelette-wavelet decomposition (VWD). The proposed algorithm classifies a degraded image into flat and edge regions by using spatial information of the wavelet coefficient. For reducing the noise we perform an adaptive wavelet shrinkage process. At edge region candidates, we adopt entropy approach for estimating the noise and remove it by using relative between sub-bands. After shrinking wavelet coefficients process, we restore the degraded image using the VWD. The proposed algorithm can reduce the noise without affecting the sharpness details. Based on the experimental results, the proposed algorithm efficiently proved to be able to restore the degraded image while preserving details.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1360-1368
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• 2010

Recently, as the development of Radio Frequency Identification (RFID) technology becomes active, the demand for services which can electronically manage the history and location information of major trees, including trees for cultural heritage restoration and nurse trees, has been increased. This information has been managed by separated drawings and documents or storing its information into PDAs and then structuring data files through input and computation. But, these methods imply limitations in terms of its extensibility and scalability. This paper has designed and implemented an RFID based Tree History Information System (THIS) for cultural heritage restoration. The purpose of the proposed system is to support to be able to effectively and consistently manage historical information of major trees and improve working processes by implementing mobile RFID services through wireless Internet or Local Area Network (LAN) as mobile communication networks. Through implementation, it is confirmed that the proposed system can manage the historical information of major trees more effectively than conventional methods and also improve previous field working conditions.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.1
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• pp.34-42
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• 2003

In this paper, the image restoration process is interpreted as a backward diffusion process and the restored image is given as the solution of the backward diffusion equation (BDF). The ill-posedness of the backward diffusion if subdued by manipulating the exponentially increasing coefficients of the eigenfunctions. In manipulating the coefficients the spectral characteristics of an image is taken into account. The proposed scheme uses an exponentially decreasing function of the coefficients of the eigenfunctions beyond a certain threshold which is optimal with respect to the observation accuracy. The use of decreasing functions also improves the result compared with the constant bounded algorithm since it can include more low frequency components.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.2
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• pp.9-18
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• 2012

The street canyon forms the geometric unit of the built environment. The geometry makes up urban canyons and it influences the urban climate. In order to investigate the wind characteristics of urban street canyon at Dogok-dong, Gangnam-gu in Seoul, the wind direction and wind speed data were observed and analyzed by using 2-D ultra sonic and propeller wind monitor from May 5, 2010 to May 4, 2011. The results show that the prevailing wind direction was west at Station A(Military Mutual Aid Association Building), southwest at Station B(Sookmyung Girls' High School) and the wind speed of Station B was higher than Station A. There were diurnal differences about prevailing wind direction between two stations : it was westerly wind at Station A for a whole day, but at Station B only from 22 : 00 to 04 : 00. However, Station B is different from Station A at other time. At Station B, it was easterly wind from 04 : 00 to 12 : 00, southwesterly wind from 12 : 00 to 22 : 00. In terms of seasonal(except winter) frequency, the spring shows the highest frequency and fall was the next.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.2
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• pp.95-104
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• 2010

The purpose of this study is to analyze the correlation between physical stream characteristics and bed materials in natural rivers. Accordingly, four natural rivers were selected reference streams, they were Nam river, Sumjin River, Naesung River and Han River. Grain size distributions of bed materials were gravels, cobbles and boulders in Han river and Nam river, were sand, gravels, cobbles and boulders in Sumjin river and were sand in Naesung river. Four reference streams were divided into each two reference reaches (straight and bend) by plan and profile characteristics of naturally meandering stream. Therefore various reference reaches were chosen in the aspect of physical stream characteristics and grain size distributions. The results investigated and analyzed are as follows. The streams that grain sizes distributions of river bed materials were coarse were stable because they had variety of bed slope without sediment deposition, and then the riffles frequency and the physical characteristics were various. Also, velocitydepth regime were various in four kinds, and the response parts for water level change were small, so that channel flow status were stable and excellent condition. On the other hand, sand river that grain sizes distributions of river bed materials were fine had not the variety of parameters as velocity-depth regimes, sediment deposition, channel flow status and riffles frequency, so that the physical stream characteristics were not various.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.1
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• pp.52-61
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• 2008

The purpose of this study is to investigate the children's different responses on the playground and facilities by the materials. For the study, the overall satisfaction on the playgrounds, the visiting frequency, the staying time, and olfactory and tactile responses were collected and analyzed by the materials. The materials for the playing facilities were categorized into 3 different groups ; steel, regular form wood and natural wood. The each group was also estimated and analyzed through the SD (sematic differential) scale which consisted of landscape adjectives. According the results, children liked and most highly scored the playground and playing facilities with natural wood in every items; overall satisfaction, visiting frequency, the staying time, and olfactory and tactile. On the other hand, the steel facilities were most negatively assessed in almost every items. Especially children felt the steel facilities were not environmentally friendly and very boring, comparing to the others. However, only 6 cases were analyzed in this study, because there were few playgrounds with natural wood facilities, so it is necessary to research on more cases to generalize these results.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.151-159
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• 2021

Since January 2019, insurance coverage for caries treatment of permanent teeth using composite resin in children aged 12 and under has started in South Korea. The purpose of this study was to compare the pattern of permanent molar composite resin restoration aged 12 and under before and after the insurance coverage from January 2009 to March 2020 in the Department of Pediatric Dentistry at Kyung Hee University Dental Hospital at Gangdong. Since the insurance coverage was started in 2019, the frequency of permanent molar composite resin restoration aged 12 and under has increased more than twice. There was a significant change in frequency of resin restoration by shape of cavity comparing before and after the insurance coverage, whereas there was no significant difference in changes by patient age, gender and position of tooth. As accessibility to the permanent tooth composite resin restoration is increased by the insurance coverage, which shows a fair survival rate, it is expected that it could be able to secure oral health in the early permanent dentition aged 12 and under.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.521-525
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• 2014

The Ussurian tube-nosed bat (Murina ussuriensis) is a registered endangered species that has not been observed in South Korea since 1960. We were able to capture three individuals of M. ussuriensis between 2011 and 2013 at Sobaeksan National Park. The discovery of this species was the first time within 50 years. To collect basic data on the M. ussuriensis, we analyzed the external morphology and ultrasound characteristics of the captured bats. The results indicated that M. ussuriensis weigh approximately 5.2 g, which is less than that of a typical small bat such as Pipistrellus abramus. The bat's wing-type ratio was determined to be 1.22 and classified as a broad and short wingspan type. The bat uses FM signals for ultrasound with a peak frequency of 92 kHz. The M. ussuriensis seems to be a forest-dwelling bat that preys on insects by maneuvering expertly within the complex mazelike structure of forests. In the future, further research on the hibernation and foraging sites of the bats is necessary to protect and monitor the species.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.1
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• pp.55-75
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• 2017

The purpose of this study is to present the basic data for restoration of physical stream environment by analyzing habitat variables because habitat environment is changed due to the construction of waterfront space in urban streams. Assessment results of 10 habitat variables(three divisions) were almost same as optimal condition, in the reach of reference stream where there are no stream crossing structures and channel alteration. Assessment results of reaches in urban rivers, where streams were improved on water-friendly recreation activities, appeared to be marginal condition. Because habitat environment got worse due to stream improvement works such as construction of weir for water landscape, stepping stones for walking, low water revetment and high water revetment, and high water channel. In addition, in the case of mid gradient stream, the frequency of riffles was small or not existed because the intervals of the river crossing structures was short. In the case of mild stream types, the diversity of the pool was damaged due to the deposition of sludge in the upstream pool of weir and the installation of low water revetment.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.500-507
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• 2011

Acoustic emission(AE) signals during the polymerization shrinkage of composite resin subjected to the LED light exposure were detected through a wave guide method and a direct sensor attachment method. For PMMA, human tooth, stainless steel substrate, data of AE hits and amplitudes were compared. For the test using the wave guide, AE amplitudes decreased because of the attenuant wave. However, AE hits and 1st peak frequency distribution were not different according to the sensor attachments. Through the experiments, wave guide could be used for a nondestructive evaluation of the marginal disintegrative fracture of dental restoration.