• Korean Journal of Environment and Ecology
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• v.10 no.1
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• pp.76-86
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• 1996

We studied the degree of damage of trees which have been chronically damaged by environmental pollutants and the area of damaged stands in each region of the middle part of Korea with three tree species - Picea abies, Abies holophylla and Pinus densiflora. So as to diagnose the degree of tree damage in an early stage, We investigated injury index and measured contact angle and finally got the following results; 1) Visible and physiological damage such as the increase of injury index and the decrease of contact angle was serious centering around metropolitan cities live Seoul and Inchon; 2) The trees of all of 14 sites surveyed were damaged by environmental pollutants although there was difference to some extent among sites. Especially, the degree of damage appeared to be increased gradually in the western parts along including Inchon, the seacoasts. In fact, more systematic studies for this issue should be continued in other regions and countermeasures should be devised.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.10a
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• pp.138-146
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• 1996

The presence of a damage, such as a crack, in a structure increases the flexibility and damping in the structure. Most of methods to detect damage or damage location uses stiffness matrix of the structural system. The modification of stiffness matrix, however, has complicated procedures to identify structural. system in the basis of finite element model and has too many degree of freedom to calculate. Identification of changes of flexibility of structure can offer damage information immediately and simple procedure can employ real time continuous monitoring system. To identify changes of the flexibility, vibration mode shapes and natural frequencies are usually used. In this paper, a procedure for damage location in continuous girder bridges using vibration data is described. The effectiveness and sensitivity of the presented method to measurement errors in mode shapes and natural frequencies are investigated using analytical results from finite element models. It is shown that the errors in the first mode shape and first natural frequency demonstrate much larger influence than those in the higher mode shapes and modal frequencies.

• Steel and Composite Structures
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• v.10 no.4
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• pp.331-348
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• 2010

Ample research effort has been oriented into developing damage indices with the aim of estimating in a reasonable manner the consequences, in terms of structural damage and deterioration, of severe plastic cycling. Although several studies have been devoted to calibrate damage indices for steel and reinforced concrete members; currently, there is a challenge to study and calibrate the use of such indices for the practical evaluation of complex structures. The aim of this paper is to introduce an energy-based damage index for multi-degree-of-freedom steel buildings that accounts explicitly for the effects of cumulative plastic deformation demands. The model has been developed by complementing the results obtained from experimental testing of steel members with those derived from analytical studies regarding the distribution of plastic demands on several steel frames designed according to the Mexico City Building Code. It is concluded that the approach discussed herein is a promising tool for practical structural evaluation of framed structures subjected to large energy demands.

• Journal of the Korean Society of Safety
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• v.36 no.3
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• pp.40-49
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• 2021

This study surveyed damage to small and medium-sized RC slab bridges, the largest in number in Korea. Four common types of damage were identified, and their static and dynamic structural behaviors were examined through structural analysis. The degree of damage was selected as an analysis parameter for three superstructures of RC slab bridges. After structural analysis, a damage assessment process was proposed that can be used as the basis for establishing maintenance yplans for these bridges. The results of the present study can be used for the safety management of RC slab bridges, classified as bridges suspected of safety flaws or requiring maintenance in load-carrying capacity tests.

• The monthly packaging world
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• s.354
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• pp.54-60
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• 2022

• Journal of Fashion Business
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• v.13 no.6
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• pp.45-60
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• 2009

This study examined the efficacy of restraining the increase of the bacteria colony of scalp according to the application of the Ayurvedic base oils and essential oils to scalp and hair. The result is as follows. The experiment illustrated that as the result of doing the paired sample t-test of a treated group and a control group according to constitutional oiling, the efficacy of the statistically significant decrease of the colony manifested in six tested groups except the group of Pitta constitution to which sesame and lavender were applied. Also, in a group that sesame was applied to Vata constitution and a group that coconut and lavender were applied to Pitta constitution, according to the passage of time, the result of being reduced the number of the colony was obtained and it showed that the oiling suitable for each constitution has the efficacy to decrease the colony of scalp. At the same time, regardless of the constitutions, the application of oils also showed the efficacy of restraining the increase of the bacteria colony of scalp. As the result of performing Paired Sample t-test for the subjective evaluation of the subjects in pre and post clinical testing, In the analysis of questionnaire that were obtained before and after the clinical testing, the results of all of the items except the item questioning a degree of inflammation appeared to be significant. That is to say, the subjects answered that a degree of keratin or a pain in scalp, an amount of sebum and a degree of hair damage were decreased after the application of oil more than before it. And in the question of a degree of hair damage, the application of oils were proved as having the efficacy to improve the hair damage.

• Journal of the Korean housing association
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• v.3 no.2
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• pp.75-88
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• 1992

The purpose of this study is to analyze the relations between the conditions of the flaws and the types of damage according to the characteristics of housing, and then to provide with some basic data for the construction of houses of good quality. The effective analytic data for this research are 558 of all 700 questionnaires gathered through distribution collection and personal interviews conducted from June 22, 1992 Through to July 6, towards the first occupants in apartment houses, tenement houses, multidetached houses, multifamily houses and detached houses that last 10 years after construction, located in Seoul and Kyungki-Do. Our major findings are as under:1) Our data reveal that the ratio of flaw occurrence by general type breaks down into noise 53.7%, crack 39.3%, dew condensation 36.9%, windows and doors 36.6%, structure and frame 35.3%, built-in materials 33.3%, the inferiority of equipments/facilities 29.0%, ill drainage 22.0%, and the leakage of water 19.3% average number of flaw occurrence, multi detached house is the highest as 13.7, apartment house 10.5, tenement house 10.5, detached house 10.51 and multifamily house 8.7.3) As regards the degree of flaw occurrence, the flaw of noise is as serious in the degree of occurence as it is high in the ratio of occurrence. Particularly, the following contrastive phenomena are found: multidetached house is normal (2.0) in the degree of occurrence but it is high in the ratio of occurrence: while multifamily house is 2.9 in the degree of occurrence but it is low in the ratio of occurrence.4) In view of the relations between the types of flaws and those of damage, the flaw type which significantly influences on the injury of spirit and health is built-in materials; the flaw types that have considerable effect on the damage of house and home life are the inferiority of equipments/facilities, due condensation, and inferior windows and doors; and the flaw types that have a bad influence over the reliance on the constructors are the inferiority of equipments/facilities, due condensation and built-in materials.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.102-111
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• 2022

Termites are a group of social insects that are one of the primary causes of damage to wooden architectural heritage. Since termite damage impairs the authenticity and structural stability of cultural heritage, it is imperative to prevent it. This study examines the extent of termite damage to wooden architectural heritage as part of efforts to prevent termite damage to nationally designated wooden architectural heritage sites across the country. The extent of termite damage to each cultural heritage was assessed qualitatively and quantitatively and comparatively analyzed by region using the results of the "Investigation on Biological Damage to Wooden Architectural Heritages" conducted by the National Research Institute of Cultural Heritage from 2016 to 2019. It involved 362 nationally designated wooden architectural heritages(25 national treasures, 157 treasures, 180 national folklore cultural heritages) and 1,104 buildings. The results were as follows: termite detection dogs reacted at 317(87.6%) of the 362 wooden heritages, with visible termite damage observed in 185 cases(51.1%). Furthermore, termite damage was confirmed using one of two methods(detection dogs or visual inspection) in 324 cases(89.5%). Of the 1,104 buildings, termite detection dogs reacted at 668(60.5%), while 339(30.7%) showed visible termite damage. Employing one of the two methods, damage was confirmed in 702 buildings(63.6%). The country was categorized into nine regions(Seoul Metropolitan Area, Gangwon, Chungbuk, Chungnam, Jeonbuk, Jeonnam, Gyeongbuk, Gyeongnam, and Jeju) to examine the termite damage rate and the degree of damage to each cultural heritage according to location. Termite detection dogs reacted to more than 70% of the cultural heritage in all regions. Visible damage was minimal in the Seoul metropolitan area(32.1%) and Gangwon(21.4%) but severe in Chungnam(65.6%), Jeonnam(67.3%), and Gyeongnam(68.2%). By quantifying the degree of termite damage of each cultural heritage as a ratio of the absence of termite damage among the total absence, the average termite damage of the cultural heritage across the country was 9.2%. Regional variance analysis showed that the cultural heritage in Jeonbuk and Jeonnam showed a statistically significantly higher degree of termite damage than the cultural heritage in the Seoul metropolitan area, Chungbuk, and Gyeongbuk. This paper comprehensively analyzed termite damage to nationally designated wooden architectural heritage. The findings are expected to be valuable in establishing policies for the preservation and management of cultural heritage sites in the future.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.505-509
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• 2020

Twitter is a useful medium to grasp various damage situations that have occurred in society. However, it is a laborious task to spot damage-related topics according to time in the environment where information is constantly produced. This paper proposes a methodology of constructing a knowledge structure by combining the BERT-based classifier and the community detection techniques to discover the topics underlain in the damage information. The methodology consists of two steps. In the first step, the tweets are classified into the classes that are related to human damage, infrastructure damage, and industrial activity damage by a BERT-based transfer learning approach. In the second step, networks of the words that appear in the damage-related tweets are constructed based on the co-occurrence matrix. The derived networks are partitioned by maximizing the modularity to reveal the hidden topics. Five keywords with high values of degree centrality are selected to interpret the topics. The proposed methodology is validated with the Hurricane Harvey test data.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.697-705
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• 2005

Vibration-based damage identification method using embedded sensitivity functions is discussed. The theory of embedded sensitivity functions is reviewed and applied to identify damage in a three degree-of-freedom system and a metallic panel. Embedded sensitivity functions are algebraic combinations of measured frequency response functions that reflect changes in the response of mechanical systems when mass, damping or stiffness parameters are changed. By comparing the embedded sensitivity functions with finite difference functions using undamaged and damaged frequency response functions, damage is shown to be properly detected, located and quantified in theory and practice assuming that structures of interest are only damaged in one location. Simulated and experimental results indicate that the technique is most effective when changes to frequency response functions are small to avoid distorsions in the estimated perturbations due to variations in the sensitivity functions.