• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.4
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• pp.347-355
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• 2013

A damage estimation method for monopile support structure of offshore wind turbine using modal properties and committee of neural networks is presented for effective structural health monitoring. An analytical model for a monopile support structure is established, and the natural frequencies, mode shapes, and mode shape slopes for the support structure are calculated considering soil condition and added mass. The input to the neural networks consists of the modal properties and the output is composed of the stiffness indices of the support structure. Multiple neural networks are constructed and each individual network is trained independently with different initial synaptic weights. Then, the estimated stiffness indices from different neural networks are averaged. Ten damage cases are estimated using the proposed method, and the identified damage locations and severities agree reasonably well with the exact values. The accuracy of the estimation can be improved by applying the committee of neural networks which is a statistical approach averaging the damage indices in the functional space.

• Fashion & Textile Research Journal
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• v.8 no.1
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• pp.134-138
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• 2006

The washing efficiency of two types of washing machine- drum(drum washing) and drum using steam jet system(steam drum washing) was studied. The purpose of this paper is to clarify the performance of new steam drum washing. The relationship between washing temperature and washing efficiency(reflectance(%)) by soil removal, and that between washing temperature and electric energy consumption, Fabric damage evaluated by Danish wear method, Fabric shrinkage(%) during laundering were investigated, and compared with those in drum washing machine. Washing efficiency of steam drum washing according to washing temperature is better than that of drum washing. Electric energy consumption and fabric damage in steam drum washing are lower than those of drum washing. Fabric damage increased as washing temperature increased. Shrinkage of fabrics in steam drum washing and drum washing are about same. Therefore, we assumed that in the case of steam drum washing using steam jet system, washing efficiency remarkably increased, and fabric damage decreased, even with a lot of saving in given electric energy and water used.

• Journal of Environmental Health Sciences
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• v.37 no.3
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• pp.173-181
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• 2011

Koo-ni Firing Range in Maehyang-ri consisted of a firing range around 'Nong-sum' and a land-based firing range in the nearby coastal area. From 1951, when the US Air Force began field firing, residents of Maehyang-ri suffered damage to health, environment, life and property due to 54 years of field firing and noise. The purpose of this article is to provide an overview of the environmental damage, property loss, and health impairment by reviewing literature and related lawsuits. Environmental damage, the destruction of coastal fisheries and wetlands, would be a result of heavy metal contamination of soil. Fishing restrictions and the confiscation of farmlands caused financial hardship. Errant bombings led to the loss of life and property, including buildings and livestock. As a result, residents repeatedly sued the Republic of Korea for damages. The court decided partially in favor of the plaintiffs. Finally, Koo-ni firing range was closed down in 2005. Through the literature review, it is presumed that the noise caused hearing problems, hypertension, and mental illness. Since earlier studies were confined to a small fragment of the damage, additional studies focused on chronic health hazards are needed.

• Korean Institute of Interior Design Journal
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• v.25 no.3
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• pp.82-89
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• 2016

This study investigated the preservation status of wooden architectural heritages, designated as Chungcheongbuk-do designated heritage in Jecheon. The purpose of this paper is to find the damage cause and the preservation method of wooden architectural heritages. It was conducted using the research methods of the existing literature and field survey to compare a current status of wooden architectural heritages. The result are as followings. Firstly, it was found the problems of a break, a damage, etc. in the platform and the problems of a cracking, an exfoliation, a corrosion, a warp, etc. in the wall. And, it was found a cracking of the beam(梁) and a roof tile(瓦), a falling of Angto(仰土), a sagging roof, etc. in the roof. Secondly, the damage causes of wooden architectural heritages were mostly caused by the physical limitations of the materials. And, it was caused by a rainwater, a subsidence of ground settlement, a destruction of waterproof membrane, etc. Lastly, the repair methods are making a quicklime layer in the soil mound on a cracking and an exfoliation part, a resin treatment or strut operation on a corrosion part of column, etc.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.5
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• pp.81-90
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• 2016

Due to droughts and water shortages causing severe damage to crops and other vegetations, much attention has been given to efficient irrigation for upland farming. However, little information has been known to measure soil moisture levels in a field scale and apply their spatial variability for proper irrigation scheduling. This study aimed to characterize the spatial variability and temporal stability of soil water contents at depths of 10 cm, 20 cm and 30 cm on flat (loamy soil) and hill-slope fields (silt-loamy soil). Field monitoring of soil moisture contents was used for variogram analysis using GS+ software. Kriging produced from the structural parameters of variogram was applied for the means of spatial prediction. The overall results showed that the surface soil moisture presented a strong spatial dependence at the sampling time and space in the field scale. The coefficient variation (CV) of soil moisture was within 7.0~31.3 % in a flat field and 8.3~39.4 % in a hill-slope field, which was noticeable in the dry season rather than the rainy season. The drought assessment analysis showed that only one day (Dec. 21st) was determined as dry (20.4 % and 24.5 % for flat and hill-slope fields, respectively). In contrary to a hill-slope field where the full irrigation was necessary, the centralized irrigation scheme was appeared to be more effective for a flat field based on the spatial variability of soil moisture contents. The findings of this study clearly showed that the geostatistical analysis of soil moisture contents greatly contributes to proper irrigation scheduling for water-efficient irrigation with maximal crop productivity and environmental benefits.

• The Korean Journal of Ecology
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• v.19 no.3
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• pp.251-260
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• 1996

The effect of forest fire on soil microarthropod fauna was investigated in the Inhoo Park, located at Deokjin-gu, Chonju city, where fire burned about 2 hectares on April 5, 1994. Vegetation of the area was covered with mixed forest such as 20 to 30 year old black locust, alder, and pine gree, etc., and also rich in understory plants, dead leaves, twigs, etc. The soil samples were taken from burnt soil and near-by control site on April 10, June 6 and Oct. 22 in 1994, and June 26, 1995. Soil microarthropods were extracted using Tullgren apparatus for 72 hours. Soil microarthropods collected in this experiment were 8, 013 at control and 3, 805 at the burnt site making a total of 11, 818 from 5 classes. Therefore, appearance of microarthropods was reduced to 52.5% at burnt site. Dominant animal groups were Acari (45%) and collembola (46%). The reduced rate of soil animal density by fire damage was 52.5% of the total soil microarthropods accounting 36% in Acari and 70% in collembola. The reduction of soil animal density by fire was 65.3% by habitat destruction and 51.7% by diret shock from fire heat. In Collembola, 89% was reduced by habitat destruction. Oribatid mites collected at sample plots included 29 families, 47 genera and 58 species. Forty-two species at burnt site and 47 species at unburnt site were identified, of these 32 being common species at both sites. The density ratio of soil animals at the burnt sites and those at unburnt sites was 38.6% va 61.4% resulting in 37% reduction due to fire. The dominant species with more than 5% in relative density were Trichogalumna nipponica (7.3%) and Eremobelba japonica (5.8%) at unburnt site, shereas 5 species including Eohypochthonius crassisetiger (8.5%) at the burnt site. The number of these species were 32.1% of total number. MGP analysis based on the number of oribatid mites indicated GP type at both unburnt and burnt sites, revealing domination of the P group in oribatid mites.

• Structural Monitoring and Maintenance
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• v.5 no.2
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• pp.231-242
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• 2018

Subway tunnel structure has been rapidly developed in many cities for its strong transport capacity. The model-based damage detection of subway tunnel structure is usually difficult due to the complex modeling of soil-structure interaction, the indetermination of boundary and so on. This paper proposes a new data-based method for the damage detection of subway tunnel structure. The root mean square acceleration and cross correlation function are used to derive a statistical pattern recognition algorithm for damage detection. A damage sensitive feature is proposed based on the root mean square deviations of the cross correlation functions. X-bar control charts are utilized to monitor the variation of the damage sensitive features before and after damage. The proposed algorithm is validated by the experiment of a full-scale two-rings subway tunnel lining, and damages are simulated by loosening the connection bolts of the rings. The results verify that root mean square deviation is sensitive to bolt loosening in the tunnel lining and X-bar control charts are feasible to be used in damage detection. The proposed data-based damage detection method is applicable to the online structural health monitoring system of subway tunnel lining.

• Journal of the Korean Home Economics Association
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• v.37 no.2
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• pp.113-126
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• 1999

In order to investigate the detergency effect of stained cotton and PET fabric, respectively, these fabrics stained with solid soils such as carbon black, liquid paraffin, and fat and examined the detergency effect in the optimum washing condition. The evaluation of washing efficiency of washed fabrics studied by using the surface reflectance measurement before and after washing treatment. The maximum detergency effect of stained cotton and PET fabric obtained in the mixed washing liquor-bleachig agen(ml)/concentrated washig agent(g/l). To obtain the excellent detergency effect, 2-step washing treatment, pre-washing by bleaching agent only and washing by concentrated detergent, is preferred. In comparing the detergency of polyester and cotton fabric, the detergency of stained polyester fabric superior than that of stained cotton fabric because of the difference of adhesive force between soil material and fabric in preparing soled stained fabric. In this study, we also studied the degree of fabric damage by the measurement of tensile strength change. From the results of the tensile strength measurement, the damage of washed fabric before and after washing treatment was nearly changed.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.305-306
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• 2003

In the case of the geosynthetics usage to soil structure, there are some damages by compaction. And these damages by the installation compaction result in the unexpected changes of short and long term properties of the structure. So in the case of index test, there are some problems to the exact evaluation on the installation damage. Therefore, to the more definite evaluation on the installation damage of geosynthetics, the real site installation damage test is encouraged. (omitted)

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.3-14
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• 1999

The Hyogoken-Nambu Earthquake of January 17, 1995 inflicted severe damage in the Hanshin and Awaji areas such as has never been seen in Japan in recent years. The safety inspections of the dams conducted in the area by site offices and dam experts immediately after the earthquake showed that there was no damage affecting the safety of the dams although slight damage was observed in several dams. The investigation also revealed that the peak accelerations at dam sites were much smaller than those at soil sites. The Ministry of construction organized the Committee on Evaluattion of Earthquake Resistance of Dams after the earthquake. The Committee confirmed through dynamic analysis that the dams designed in accordance with the present design criteria in Japan are safe under the magnitude of shaking that occurred close the source fault of the Hyogoken-Nambu Earthquake.