• Title/Summary/Keyword: Fatigue Behavior

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Experimental Analysis of Large Size Concrete-Filled Glass Fiber Reinforced Composite Piles Subjected to the Flexural Compression (대구경 콘크리트 충전 복합소재 파일의 휨-압축 거동에 대한 실험적 분석)

  • Lee, Sung Woo;Choi, Sokhwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.5A
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    • pp.519-529
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    • 2009
  • Fiber reinforced composite materials have various advantages in mechanical and chemical aspects. Not only high fatigue and chemical resistance, but also high specific strength and stiffness are attained, and therefore, damping characteristics are beneficial to marine piles. Since piles used for marine structures are subjected to compression and bending as well, detailed research is necessary. Current study examine the mechanical behavior under flexural and/or compressive loads using concrete filled fiber reinforced plastic composite piles, which include large size diameter. 25 pile specimens which have various size of diameters and lengths were fabricated using hand lay-up or filament winding method to see the effect of fabrication method. The inner diameters of test specimens ranged from 165 mm to 600 mm, and the lengths of test specimens ranged from 1,350 mm to 8,000 mm. The strengths of the fill-in concrete were 27 and 40 MPa. Fiber volumes used in circumferential and axial directions are varied in order to see the difference. For some tubes, spiral inner grooves were fabricated to reduce shear deformation between concrete and tube. It was observed that the piles made using filament winding method showed higher flexural stiffness than those made using hand lay-up. The flexural stiffness of piles decreases from the early loading stage, and this phenomenon does not disappear even when the inner spiral grooves were introduced. It means that the relative shear deformation between the concrete and tube wasn't able to be removed.

A Study on Health Behaviors and Problems of Female Retail Workers (유통업 여성 근로자의 건강 문제와 건강 행위에 관한 연구)

  • Kim, Souk-Young;Yun, Soon-Nyung
    • Research in Community and Public Health Nursing
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    • v.11 no.1
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    • pp.127-145
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    • 2000
  • The objectives of this study are to identify health behaviors and health problems. and the relations between health behaviors and health problems of female workers in the retail business. The number of subjects were 200 female workers of 6 department stores in Seoul and Kyonggi area, whose jobs last more than 6 months as retail employees. The data was collected during 2 months from July 1 to August 30, 1998. The Cornell Medical Index Health Questionnaire(CMI) was used to measure their health problems, while health behaViorn were investigated in terms of 'smoking', 'alcohol', exercise', 'diet', and 'sleeping'. The data were analyzed with frequency. percentage, t-test, ANOVA test, and $X^2-test$ by SPSS PC+ program. The results of this study are as follows: 1. Out of health problems. Digestive symptoms occupied the highest percent number. nervous ones the second and cardiovascular ones the third among physical health problems of retail female workers. The most frequent mental health problem was 'adequacy' and the next, 'tension' and 'anger', 2, Health problems according to general characteristics of subjects were shown that the younger or the unmarried complained more than the older or the married, especially in the items of 'eye and ear', 'respiratory system', 'cardiovascular system', 'digestive tract', 'nervous system', 'adequacy', and 'depression'. The longer working duration they have had, the more they complained of 'respiratory system' and 'adequacy'. The lower academic careers complained of 'nervous' than the higher ones with statistical significance. 3. The analysis of daily health clinic notes showed that respiratory complaints were the highest percent, successively followed by digestive tract, nervous one, external injury, musculoskeletal system, urinary-reproductive system and others. 4. The level of their health practice was generally low in smoking, diet habit and alcohol intake, exercise, sleeping, very low especially in smoking, diet, alcohol intake, and exercise among them all. 5. Present smokers and ones with past experience complained of physical and mental health problems of 'respiratory system', 'digestive tract', 'skin', 'nervous', 'urinary-reproductive system', 'fatigability', adequacy', 'depression', 'anxiety', 'anger' and 'tension', than non smokers, with statistical difference. Workers without having breakfast and with irregular diet had more complaints on 'digestive tract', 'adequacy' and 'tension', than those who had regular dietary habit. The less the subjects slept, the more they complained of eye and ear, cardiovascular system. The subjects who drank alcohol complained more digestive problem. However, whether they exercise or not did not affect physical and mental health problems in a significant manner. 6. The subjects' age and marital status were statistically significant relating to health behaviors, as the younger or unmarried recorded a low level of health practice in smoking, drinking, dietary habit. Based on the results, the suggestions are made as follows: 1. Health education program on smoking, alcohol intake, diet habit is needed to improve health problems and health behavior of female retail workers. 2. The unmarried workers of late teen and twenties, who are transitional period from teenagers to adulthood are important targets for health promotion program especially for maternal health. 3. Better working environment with sufficient time and facilities for workers to relax is required to promote female sales workers' health. 4. Further research is required to identify the relation between workers' visual fatigue and intense lights for the display of goods.

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An Empirical Study of Discontinuous Use Intention on SNS: From a Perspective of Society Comparison Theory (사회비교이론 관점에서 살펴본 SNS 이용중단 의도)

  • Cha, Kyung Jin;Lee, Eun Mok
    • The Journal of Society for e-Business Studies
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    • v.20 no.3
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    • pp.59-77
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    • 2015
  • Social networking sites (SNS), such as Facebook, provide abundant social comparison opportunities. Given the widespread use of SNSs, the purpose of the present study was to examine the impact of exposure to social media-based social comparison on user's negative emotions and discontinuous use intention on SNS. We present evidence that under the use of SNS, social comparison activities diverge into three patterns, with explicit self-evaluation desire made against similar target (lateral comparison), self-defense desire made against less fortunate target (downward comparison), and self-enhancement desire made with more fortunate target (upward comparison). Such social comparison processes frequently arise, as people are increasingly using on SNSs, the downward contacts ameliorating self-esteem with positive emotions, but the upward contacts and standard contacts with lateral status enabling a person to compare his or her situation with others and simultaneously increase negative emotions due to its differences with others. In other words, as people increasingly relying on SNSs for a variety of everyday tasks, they risk overexposure to upward or standard social comparison information that may have a cumulative detrimental impact on future intention on SNS use. This study with survey with 209 SNS users found that these negative emotions lead to negative fatigue (attitude) and then discontinuous use intention (behavior) on SNS. Our findings are among the first to explicitly examine discontinuous use intention on SNS using social comparison theory and our results are consistent with those of past research showing that upward social comparisons can be detrimental.

Information types and characteristics within the Wireless Emergency Alert in COVID-19: Focusing on Wireless Emergency Alerts in Seoul (코로나 19 하에서 재난문자 내의 정보유형 및 특성: 서울특별시 재난문자를 중심으로)

  • Yoon, Sungwook;Nam, Kihwan
    • Journal of Intelligence and Information Systems
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    • v.28 no.1
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    • pp.45-68
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    • 2022
  • The central and local governments of the Republic of Korea provided information necessary for disaster response through wireless emergency alerts (WEAs) in order to overcome the pandemic situation in which COVID-19 rapidly spreads. Among all channels for delivering disaster information, wireless emergency alert is the most efficient, and since it adopts the CBS(Cell Broadcast Service) method that broadcasts directly to the mobile phone, it has the advantage of being able to easily access disaster information through the mobile phone without the effort of searching. In this study, the characteristics of wireless emergency alerts sent to Seoul during the past year and one month (January 2020 to January 2021) were derived through various text mining methodologies, and various types of information contained in wireless emergency alerts were analyzed. In addition, it was confirmed through the population mobility by age in the districts of Seoul that what kind of influence it had on the movement behavior of people. After going through the process of classifying key words and information included in each character, text analysis was performed so that individual sent characters can be used as an analysis unit by applying a document cluster analysis technique based on the included words. The number of WEAs sent to the Seoul has grown dramatically since the spread of Covid-19. In January 2020, only 10 WEAs were sent to the Seoul, but the number of the WEAs increased 5 times in March, and 7.7 times over the previous months. Since the basic, regional local government were authorized to send wireless emergency alerts independently, the sending behavior of related to wireless emergency alerts are different for each local government. Although most of the basic local governments increased the transmission of WEAs as the number of confirmed cases of Covid-19 increases, the trend of the increase in WEAs according to the increase in the number of confirmed cases of Covid-19 was different by region. By using structured econometric model, the effect of disaster information included in wireless emergency alerts on population mobility was measured by dividing it into baseline effect and accumulating effect. Six types of disaster information, including date, order, online URL, symptom, location, normative guidance, were identified in WEAs and analyzed through econometric modelling. It was confirmed that the types of information that significantly change population mobility by age are different. Population mobility of people in their 60s and 70s decreased when wireless emergency alerts included information related to date and order. As date and order information is appeared in WEAs when they intend to give information about Covid-19 confirmed cases, these results show that the population mobility of higher ages decreased as they reacted to the messages reporting of confirmed cases of Covid-19. Online information (URL) decreased the population mobility of in their 20s, and information related to symptoms reduced the population mobility of people in their 30s. On the other hand, it was confirmed that normative words that including the meaning of encouraging compliance with quarantine policies did not cause significant changes in the population mobility of all ages. This means that only meaningful information which is useful for disaster response should be included in the wireless emergency alerts. Repeated sending of wireless emergency alerts reduces the magnitude of the impact of disaster information on population mobility. It proves indirectly that under the prolonged pandemic, people started to feel tired of getting repetitive WEAs with similar content and started to react less. In order to effectively use WEAs for quarantine and overcoming disaster situations, it is necessary to reduce the fatigue of the people who receive WEA by sending them only in necessary situations, and to raise awareness of WEAs.

A study on knowledge, self-efficacy and compliance in Reumatic arthritis Patients (류마티스 관절염 환자의 지식, 자기효능감 및 치료이행과의 관계연구)

  • Kim, Soon-Bong
    • Journal of muscle and joint health
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    • v.5 no.2
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    • pp.238-252
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    • 1998
  • Reumatic arthritis is a disease with joint pain being one of the key symptoms. The patient suffers from the pain, stiff sensation and edema due to the inflammation taking Place In one or more joints. Accompanying these problems are fatigue, unusual exhaustion, fever, tachycardia and weakness. Inaddition, joints are often deformed and muscles shrink along with the progress of edema, coupled with depression and psychological instability resulting from the loss of the mobile function and limitations on the daily life. Some patients become fed up with the long and hard flight with the disease and just give up, which aggravates the symptoms. Others come to the hospital only when the conditions have become serious. We need to prevent these and guide the patients in the right direction. Against this backdrop, this study aims to look into the relations between the knowledge on the part of the patients together with their feeling of self-efficacy and the compliance. The results are expected to help the patients improve their life, In addition to providing useful materials for setting up appropriate plan for nursing intervention. The study was conducted by distributing questionnaire to 88 patients selected from the out-patient department of a university hospital in Inchon, from April 6 to 27, 1998. The following tools were used the yardstick of self-efficacy, developed in 1997 by the Society for the Health of Rheumatism Patients, was used for measuring the levels of knowledge and the feeling of self-efficacy. The degree of compliance was measured by the data collected from documents in addition to the results of the analysis of the interviews with the patients. The reliability of the tools was confirmed. In the analysis, the general characteristics were expressed in figures and percentages. The levels of knowledge, feeling of self-efficacy, and compliance were expressed in the average values and standard deviations. The relations among the variables following the general characteristics were analysed by the t-test and one-way ANOVA. The Pearson correction coefficient was used for the analysis of factors. Multiple-loop analysis was used to identify the variables affecting the compliance. The following are the results of this study. 1. Among the 88 patients, 18 were men and the remaining 70 were women, with a ratio 1 : 3.87. Regarding the age groups, 23 were between 50 and 59 years old, with those between 50 and 69 accounting for 51.1% of the total. High school graduates or higher amounted to 58%. Religious patients was 67% or 59 persons. Fifty nine percent were unemployed, and 58.3% (49 persons) had two children or fewer. The period of suffering from rheumatism varied between 2 months and IS years, with 70% less than years. 2. The average figure In relation to the of knowledge was 17.63 points over 30 or 58. 76%, which means a medium level. 3. The average figure of the feeling of self-efficacy was 60.06 points. 4. The level of compliance was 3.26, which was above average. 5. The relation between the feeling of self-efficacy and compliance showed an "r" value of 0.37, which was significant. It means that the higher the feeling, the greater the compliance points. 6. The analysis of the knowledge level revealed that the difference is found only between the college graduates and junior-high graduates or lower. 7. The feeling of self-efficacy varied along with the age and education level. 8. The general characteristics of patients as discussed above did not show significant difference with the compliance. 9. Regarding the elements influencing the compliance, the number of children, period of suffering, income, age, feering of self-efficacy, knowledge, and compliance had 54% of significance. In conclusion, rheumatism victims can lead a better life if they are appropriately educated, based on efficient training program from the early days of the disease ; if they become able to manage themselves thanks to the training ; and if they are helped by a program focusing on the increase of the feeling of self-efficacy aimed at changing patient's behavior.

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Effects of School Attendance Policy on Breakfast Eating, Sleep, and Physical Activity in Middle School Students (9시 등교정책이 중학생의 아침식사, 수면 및 신체활동에 미치는 영향)

  • Kim, Ha Na;Kim, Seong Yeong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.11
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    • pp.1397-1407
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    • 2017
  • The aim of a school attendance policy (SAP) is to ensure breakfast time for school-aged adolescents. Therefore, this study investigated the effects of SAP on dietary behavior, particularly breakfast consumption, among adolescent middle school students (n=426) in the Ansan area of Gyeonggi-do. After implementation of the SAP, the response rates for eating breakfast every-day among boys (P>0.05) and girls (P<0.05) slightly increased by 44.6% and 35.8%, respectively, compared to before the SAP. Further, the degree of satisfaction with breakfast increased among both boys ('satisfied' and 'strongly satisfied'; 32.4% and 21.6%, respectively) (P<0.01) and girls ('satisfied' and 'strongly satisfied'; 32.8% and 14.2%, respectively) (P<0.001) compared to before the SAP. Moreover, boys (56.8%) and girls (53.9%) were aware that the SAP increased breakfast-eating frequency. Increases in deep sleep as a result of the SAP were high in both boys (39.2%) and girls (47.1%), and sleeping hours among boys (P<0.05) and girls (P<0.01) increased compared to before the SAP. The respondents were aware of the positive effects on physical function such as reduction of physical fatigue (boys 40.1%, girls 38.2%) and improvement of physical health (boys 36.5%, girls 32.8%). Thus, systematic and sustained political support at the national level is required to encourage healthy breakfast eating and physical activity in middle school students.