• Title/Summary/Keyword: Predominant frequency

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Vibration based bridge scour evaluation: A data-driven method using support vector machines

  • Zhang, Zhiming;Sun, Chao;Li, Changbin;Sun, Mingxuan
    • Structural Monitoring and Maintenance
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    • v.6 no.2
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    • pp.125-145
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    • 2019
  • Bridge scour is one of the predominant causes of bridge failure. Current climate deterioration leads to increase of flooding frequency and severity and thus poses a higher risk of bridge scour failure than before. Recent studies have explored extensively the vibration-based scour monitoring technique by analyzing the structural modal properties before and after damage. However, the state-of-art of this area lacks a systematic approach with sufficient robustness and credibility for practical decision making. This paper attempts to develop a data-driven methodology for bridge scour monitoring using support vector machines. This study extracts features from the bridge dynamic responses based on a generic sensitivity study on the bridge's modal properties and selects the features that are significantly contributive to bridge scour detection. Results indicate that the proposed data-driven method can quantify the bridge scour damage with satisfactory accuracy for most cases. This paper provides an alternative methodology for bridge scour evaluation using the machine learning method. It has the potential to be practically applied for bridge safety assessment in case that scour happens.

The Domestic Trend of Studies on 3D Printing Technology Applied to the Fashion Industry

  • Choi, Jeongwook;Park, Sanghee
    • Journal of Fashion Business
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    • v.24 no.6
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    • pp.80-88
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    • 2020
  • This study, by analyzing previous studies, aimed to understand how 3D printing technology is applied and utilized in the fashion industry and to contribute to encouraging further studies on 3D printing technology in the fashion sector and suggesting proper ways for designing such studies. Firstly, 47 papers were selected from all literature concerning 3D printing technology published in 15 journals of fashion and design since 2013. Afterwards, these papers were analyzed with regard to the frequency, topics or sectors, and purposes or types of studies shown by outcomes. Results were as follows: First, the number of papers on 3D printing technology published in the journals was counted according to the year, which showed that this number increased rapidly after 2015 for about 3 years. Especially in the year 2016, this increase was quite notable. Although a little decrease in this number was found afterwards, a steady increase was highly expected. Out of the 8 journals, Journal of The Korean Society of Fashion Design had the maximum papers. Regarding areas of studies, works on designing and development of products were most common. Finally, regarding the purpose of studies, those suggesting or presenting apparel were predominant. Product items included clothes, shoes, and caps. Studies on caps mostly covered designing the products. Studies on clothes aimed at designing, characteristics of construction, and case study. However, there were very few works on 3D printing technology as an alternative material or composition of clothing.

Association between Food Content Watching and Nutrition Quotient in Adolescents (NQ-A) in Seoul (서울 일부 지역 청소년의 음식 콘텐츠 시청과 영양지수(NQ-A)와의 관련성)

  • Bo-Mi, Kim;Kyung-Hee, Kim
    • Journal of the Korean Society of Food Culture
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    • v.38 no.1
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    • pp.61-72
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    • 2023
  • In this study, we identified the differences in food content watching habits and nutrition quotient in adolescent (NQ-A). A total number of 811 subjects were surveyed to establish their general characteristics, food content watching habits, and NQ-A using a self-administered questionnaire. In addition, the mediating effect of watching motivation between the type of food content watched and the NQ-A score was determined. The classification by the type of the food content mainly watched showed that 405 participants (49.9%) watched the Mukbang content, 244 (30.1%) the Cookbang content, and 162 (20.0%) another contents. Among the content watching motives in the Cookbang content group, information acquisition and enjoyment were predominant, whereas emotional satisfaction had the lowest frequency. Compared to the Mukbang content group, when the Cookbang content group mediated information acquisition motivation, the scores of the total, diversity, balance, and practice of NQ-A score areas increased. Compared to the Mukbang content group, the score in the moderation area decreased when the Cookbang content group mediated enjoyment motivation. If food content with accurate information and interesting content are produced and used for adolescent nutrition education, the education will be highly effective.

A Comparative Study on the Status and Utilization Types of Closed Schools in Rural and Islands - Comparative Study of Closed School in Goesan-gun, Chungcheongbuk-do, and Sinan-gun, Jeollanam-do - (농촌지역과 도서지역의 폐교 현황과 활용 유형 비교 연구 - 충청북도 괴산군과 전라남도 신안군 폐교를 중심으로 -)

  • Moon, Seang Hyen
    • Journal of the Korean Institute of Rural Architecture
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    • v.26 no.1
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    • pp.11-20
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    • 2024
  • Due to the decrease in the school-age population and the overall population, school closures will continue to occur. Currently, most school closures are happening in rural areas, where geographical conditions often result in relatively poor educational, welfare, and cultural facilities compared to urban areas. Additionally, the proportion of elderly populations and migrant women is continuously increasing. In order to effectively utilize closed schools in the future, various efficient utilization methods that align with the social context of the respective regions will be necessary. The purpose of this study is to examine the status of closed school and utilization types in selected rural and island areas of similar sizes through field surveys and literature reviews. By comparing and analyzing these findings, we have identified the predominant utilization types in rural and island areas and assessed the current situation where utilization is lacking. Based on the results, we aim to provide fundamental data for improving and enhancing the utilization of school closures in the face of the ongoing decline in the school-age population.

A review of chloride induced stress corrosion cracking characterization in austenitic stainless steels using acoustic emission technique

  • Suresh Nuthalapati;K.E. Kee;Srinivasa Rao Pedapati;Khairulazhar Jumbri
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.688-706
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    • 2024
  • Austenitic stainless steels (ASS) are extensively employed in various sectors such as nuclear, power, petrochemical, oil and gas because of their excellent structural strength and resistance to corrosion. SS304 and SS316 are the predominant choices for piping, pressure vessels, heat exchangers, nuclear reactor core components and support structures, but they are susceptible to stress corrosion cracking (SCC) in chloride-rich environments. Over the course of several decades, extensive research efforts have been directed towards evaluating SCC using diverse methodologies and models, albeit some uncertainties persist regarding the precise progression of cracks. This review paper focuses on the application of Acoustic Emission Technique (AET) for assessing SCC damage mechanism by monitoring the dynamic acoustic emissions or inelastic stress waves generated during the initiation and propagation of cracks. AET serves as a valuable non-destructive technique (NDT) for in-service evaluation of the structural integrity within operational conditions and early detection of critical flaws. By leveraging the time domain and time-frequency domain techniques, various Acoustic Emission (AE) parameters can be characterized and correlated with the multi-stage crack damage phenomena. Further theories of the SCC mechanisms are elucidated, with a focus on both the dissolution-based and cleavage-based damage models. Through the comprehensive insights provided here, this review stands to contribute to an enhanced understanding of SCC damage in stainless steels and the potential AET application in nuclear industry.

Effects of Heated Effluents on the Intertidal Macroalgal Community near Uljin, the East Coast of Korea (동해안 울진원전의 온배수 방출이 주변 해조군집에 미치는 영향)

  • Kim, Young-Hwan;Ahn, Jung-Kwan;Lee, Jae-Il;Eum, Hee-Moon
    • ALGAE
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    • v.19 no.3
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    • pp.257-270
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    • 2004
  • In order to clarify the structure and seasonal dynamics of warm tolerant benthic marine algal community in Korea, the species composition and biomass of marine algae at the discharge canal of Uljin nuclear power plant on the East Coast of Korea were investigated seasonally from February 1992 to October 2000. 107 species of marine algae were found at the discharge canal during the past nine years. In general, the number of species observed was abundant in spring or summer and less in autumn or winter. 27 species (4 blue-green, 5 green, 6 brown and 12 red algae) of marine algae occurred more than 1/ 6 frequency and thus can be categorized as warm tolerant species. Among these, one brown (Dictyota dichotoma) and four red algae (Gelidium amansii, Anphiroa ephedraea, Hydrolithon sargassi, Marginisporum crassissimum) are recorded as warm tolerant marine algae for the first time in Korea. Padina arborescens, Anphiroa zonata and Corallina pilulifera were common species found more than 75% frequency. Seasonal fluctuations of mean biomass were 0-1,330 g dry wt m^(-2) and dominant species in biomass were Corallina pilulifera (contribution to a total biomass proportion 34%), Anphiroa zonata (23%), Padina arborescens (18%) and Sargassum micracanthum (11%). The red algae appeared as predominant algal group at the discharge canal of Uljin nuclear power plant in the qualitative and quantitative aspects. The green algae such as Enterornorpha compressa appeared rather frequently at the discharge canal, but the biomass proportion was very low, in contrast to Kori nuclear power plant where there was definite green algal dominance. Differences in algal communities developed at the discharge canals of Uljin and Kori nuclear power plant on the East Coast of Korea, particularly biomass proportions of green algae, can probably be related to local environmental factors such as water velocity through the canal and natural seawater temperatures.

Which Environmental Factors Caused Lammas Shoot Growth of Korean Red Pine?

  • Lee, Chang-Seok;Song, Hye-Gyung;Kim, Hye-Soo;Lee, Bit-Na-Ra;Pi, Jeong-Hoon;Cho, Yong-Chan;Seol, Eun-Sil;Oh, Woo-Seok;Park, Sung-Ae;Lee, Seon-Mi
    • Journal of Ecology and Environment
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    • v.30 no.1
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    • pp.101-105
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    • 2007
  • Lammas growth, a rare phenomenon for Korean red pine (Pinus densiflora), occurred in 2006. Lammas shoots showed higher frequency and longer length in Seoul's hotter urban center than in urban boundary or suburban forest sites. Frequency and length showed a close correlation with urbanization density and vegetation cover expressed in NDVI. Air temperature in the late summer of 2006 was more than $1^{\circ}C$ higher than an average year. Of the predominant environmental signals that modulate bud flush, only temperature changed significantly during the year. Differences in temperature between the urban centers, urban boundaries and suburban forests correlated with varying land-use density. The rise in temperature likely spurred lammas growth of the Korean red pine. Symptoms of climate change are being detected throughout the world, and its consequences will be clearer in the future. Considerate interest in the responses of ecological systems to the variable changes is required to prepare for unforeseeable crises. Monitoring of diverse ecological phenomena at Long Term Ecological Research sites could offer harbingers of change.

A Comparative Study of Casual Styles Between Korean and Chinese Women - Focusing on 2008 Summer Street Fashion in Seoul and Shanghai - (한국과 중국 여성의 캐주얼 스타일 비교연구 - 2008년 여름 서울과 상하이의 스트리트 패션을 중심으로 -)

  • Dong, Bei;Oh, Hyun-A;Bae, Soo-Jeong
    • Journal of the Korean Society of Costume
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    • v.59 no.9
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    • pp.97-114
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    • 2009
  • The purpose of this thesis is to contribute to the fashion industry of Korea and China by providing the basic informations of Korean fashion company planning to launch into the Chinese fashion market, and also presenting the Korean fashion style to the China, by the way of searching the sameness and differences of the casual style. The direct picturing method and comparative analysis were applied for the methods of study. The whole body pictures were taken from the major fashion streets of Seoul and Shanghai, then clear 250 photos were selected in each city. The period for two weeks from 1st, July to 14th, July 2008, and from 10AM until 5PM. The results of study are as follows. The sequential order of frequency is easy casual, jean casual, romantic casual and character casual in Seoul and Shanshai. In case of easy casual, there were many similarities of the preferences in the items, colors and coordinations, while showing the differences in the styling of the clothing. Taking the jean casual, there were no specific differences in items between two cities except the styling of clothing in which the tidy style were more prevalent in Seoul, while the sexy style were more predominant in Shanghai. The main item of romantic style was the one-piece dresses. This was preferred in the style of A-line or H-line with short length, in Seoul while X-silhouette showing the body line with knee-length skirts were more popular in Shanghai. Finally the frequency of character casual is below 5% in both cities. In the items, the skirts were more preferred as a bottom in Seoul in contrast with the pants being more prevalent in Shanghai, the sleeveless top popular in both cities. The modest style were noted in Seoul, the sexy style were more prevalent in Shanghai. However many similarities between two cities were found in the speed of acceptabilities of fashion.

Risk Factors Associated with Thyroid Carcinoma in North Pakistan

  • Khan, Muhammad Aleem;Khan, Kamran Hakeem;Shah, Sajid Ali;Mir, Kahkashan Ali;Khattak, Mubarik;Shahzad, Muhammad Faheem
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.1
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    • pp.377-380
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    • 2016
  • Background: Epidemiological data on thyroid cancer and associated risk factors are scarce in our setting. The present study was therefore designed to gather data which could be helpful in providing insights to thyroid physicians and surgeons for better management of affected patients. Purpose: To determine the frequency of carcinoma thyroid among patients presenting with goiter and its association with TSH, Tg/ATg and other demographic factors. Materials and Methods: A total of 73 adult patients of either gender with solitary solid cold nodules and/or multi-ndoular goiter (MNG) with predominant solid cold nodules were enrolled. All surgically resected samples were sent for histopathology. The frequency of thyroid cancer and its subtypes was noted and tested for association with gender, age (< or ${\geq}40years$), recent increase in swelling size, TSH, Tg and ATg. Results: Thyroid cancer was diagnosed in 26% (n=19) of the patients, 14 (73.7%) being diagnosed with papillary thyroid cancer and 5 (26.3%) with follicular thyroid cancer. No other subtypes were noted. Presence of thyroid cancer was significantly associated with recent increase in swelling size and higher TSH Values mean TSH values (P<0.05). No significant association was found with gender, age, Tg and ATg values (P>0.05). Conclusions: Overall percentage of thyroid cancer in our study sample was found to be 26%, with a predominance of papillary over follicular lesions. Rates were significantly higher in patients who had history of recent increase in swelling size and higher and higher pre-surgery TSH values.

Ecological Characteristics of Marine Algal Communities at the Discharge Canals of Three Nuclear Power Plants on the East Coast of Korea (동해안 3개 원전 배수로 해조군집의 생태적 특성)

  • Kim, Young-Hwan;Ahn, Jung-Kwan
    • ALGAE
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    • v.20 no.3
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    • pp.217-224
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    • 2005
  • The species composition and biomass of marine algae at the discharge canals of three (Gori, Wolseong and Uljin) nuclear power plants on the east coast of Korea were investigated seasonally from February 1992 to October 2000. As a result, 103-107 species of marine algae were found at the discharge canals during the past nine years. In general, algal communities established at the discharge canals were less diverse than those at the intake canals and control sites. 43 species (6 blue-green, 9 green, 10 brown and 18 red algae) of marine algae occurred more than 1/6 frequency and thus can be categorized as warm tolerant species. Among these, two green (Urospora penicilliformis, Cladophora albida), four brown (Sphacelaria divaricata, S. rigidula, Sargassum coreanum, S. fulvellum) and four red algae (Stylonema alsidii, Bangia atropurpurea, Hypnea charoides, Chondria crassicaulis) are recorded as warm tolerant marine algae for the first time in Korea during this study. Enteromorpha compressa, Padina arborescens, Amphiroa zonata and Ahnfeltiopsis flabelliformis were common species found more than 50% frequency at the discharge canals of all three nuclear power plants investigated. Dominant species in biomass were Padina arborescens and Amphiroa zonata. Results showed that, as a whole, the red algae appeared as predominant algal group at the discharge canals of all three nuclear power plants on the east coast of Korea. However, the biomass proportion of dominant algae at the discharge canals of each nuclear power plant varied over the year during the past nine years.