• 터널과지하공간
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• 제25권1호
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• pp.24-36
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• 2015

거창화강암은 국내 주요 석재자원의 하나로서 토목 및 건축사업에 널리 사용되고 있다. 본 연구에서는 거창화강암을 대상으로 수많은 실내시험을 실시하여 암석의 단위중량, 흡수율, P파 속도, S파 속도, 일축압축강도, 인장강도, 영률, 포아송비, 점착력, 내부마찰각, 점하중강도지수 등의 물리적 성질을 조사하였다. 일축압축강도는 인장강도의 19.5배, 점착력의 8.6배이고, P파 속도는 S파 속도의 1.5배 수준이었다. 실험결과로 얻어진 각종 물성간의 상호관계를 분석하였으며, 일축압축강도는 포아송비, 점하중강도지수, 영률과 0.8 이상의 피어슨 상관계수를 보였다. 또한, 단순회귀분석과 다중회귀분석을 통해 물성간의 각종 회귀식을 구하였으며, 특히 결정계수 0.7이상의 회귀식을 정리하여 나타내었다.

• 국제물리치료학회지
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• 제8권1호
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• pp.1105-1113
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• 2017

The Purpose of this study was to determine the effects of sciatic nerve mobilization on pain and lower back muscle strength in female patients in their 40s who have been diagnosed with lumbar radiculopathy. Using a simple blinded method, 20 female patients with neuropathy in the nerve segments between L4-S1 were randomly divided into one group (n=10) that would undergo sciatic nerve mobilization, and another group (n=10) that would perform lower back segment stabilization exercises. The two groups attended 3 sessions per week, with each session taking 30 minutes, for a duration of 4 weeks. In the preliminary examinations, the pain index as well as the isometric muscle strength of the lower back extensor and flexor muscles were measured. After the passing of 4 weeks. The same method of measurement was used for the concluding examinations. Comparison of the pain indices in the two groups revealed that they both experienced a statistically significant decrease, and further inspection revealed that the there was a more substantial difference in the sciatic nerve mobilization group. Results of comparing changes in the Isometric Muscle Strength lower back muscle and bending muscle by group, In comparison between groups, the isometric strength of the lower back extensor showed a more significant difference in the sciatic nerve mobilization group (p <.05). Conclulsion, it can be inferred that application of sciatic nerve mobilization has a positive effect on the pain index and isometric muscle strength of the lower back in female patients with lumbar radiculopathy in their 40s.

• 대한인간공학회지
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• 제28권3호
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• pp.125-134
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• 2009

The muscle strengths in various postures are used in our daily life with or without our recognition. Also, many works are still performed with strengths, although mechanization and automation have been fairly accomplished at the industry site. Since the late seventies, various body measurements have been conducted periodically in Korea, however, muscle strengths have not been measured actively. For this reason, the muscle strength data have been hardly accumulated. The aims of this study are to learn more about the physical strength of young-aged Koreans and to provide basic information for designing equipments, tools and facilities in the work site and daily life. The muscle strengths that are related to shoulder and upper limbs joints, which are used frequently, are measured in this study. Eighteen muscle strengths, from seven different movements such as elbow flexion, elbow extension, shoulder abduction(seated), shoulder adduction(seated), shoulder rotation(internal and external), lifting a tray, and turning a key(inward and outward) were measured. For every movement, the muscle strengths for both hands were measured. In each measurement, five seconds averaged value and peak value were collected. Comparing the average value, the strength of shoulder adduction was the strongest for male and female, while strength of turning a key inward with left hand was the weakest for male and female. Strengths of preferred hand in elbow extension, shoulder abduction, shoulder external rotation, lifting a tray, and turning a key were stronger than those of non-preferred hand for both male and female. Rohrer's index considerably had an effect on muscle strength. The results of this study can provide some basic information not only in designing the equipment and facilities in work site or daily life, but also in selection, training and management of workers.

• 한국학교보건학회지
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• 제33권3호
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• pp.203-212
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• 2020

Purpose: The purpose of this study was to investigate the relationship between relative handgrip strength (HGS/BMI) and obesity (BMI above 95th percentile) in adolescents. Methods: The subjects of the study were 637 out of 701 adolescents aged 10~18 who participated in the 2018 National Health and Nutrition Survey (KNHANES), excluding those with missing values in body mass index (BMI) and handgrip strength (HGS). The relative handgrip strength (HGS/BMI) value was divided by quartile and composite sample logistic regression analysis was performed to see its relationship with obesity (BMI above 95th percentile). The collected data were analyzed using SPSS 18.0. Results: As a result of analyzing HGS according to gender-specific quartiles, age, height, and weight of male adolescents increased significantly as HGS/BMI increased (p trend<.001). In addition, as HGS/BMI increased, total cholesterol, triglycerides, and HDL cholesterol decreased significantly (p trend<.001). In the case of female adolescents, age and height increased significantly as HGS/BMI increased (p trend<.001). HGS/BMI was lower in the obese group (p=.023), while total cholesterol was higher in the obese group(BMI above 95th percentile) than in the non-obese group. As a result of the composite sample logistic regression analysis, the odds ratio (OR) decreased significantly as the quartile increased in both male and female adolescents. Conclusion: According to these results, a follow-up study is needed to confirm the factors affecting muscle strength of adolescents. In addition, this study intends to be used as basic data to conduct further research and to develop programs that can improve muscle strength and reduce obesity in adolescents.

• 대한통합의학회지
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• 제10권3호
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• pp.63-72
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• 2022

Purpose : Several studies have investigated the effects of dynamic stretching (DS) and self-mobilization (SM), however, studies comparing the two interventions are rare. Therefore, the purpose of this study was to compare the effects of DS and SM on ankle strength, dorsiflexion range of motion (DFROM), and balance to determine which is superior. Methods : Thirty-two healthy young adults participated in this study. Participants were randomly assigned to two groups (SM and DS). DS was performed for the purpose of stretching the medial gastrocnemius muscle. For the SM group, ankle joint SM was performed in three ways. For all participants, the following measurements were performed as pre- and post-tests: isometric strength of dorsiflexor and plantar flexor, weight-bearing lunge test (WBLT) to evaluate DFROM, Tetrax system to evaluate static balance, and y balance test (YBT) to evaluate dynamic balance. Differences before and after the intervention within each group were compared using paired t-test. Also, the variable's variation was compared between groups using an independent t-test. Results : Significant differences were found in ankle dorsiflexor strength, WBLT, YBT, weight distribution index (WDI) (pillow and opened eyes; PO), and stability index (ST) (normal and closed eyes; NC) before and after intervention in the SM group (p<.05). In the DS group, significant differences were found in ankle dorsiflexor and plantar flexor strength, WBLT, YBT anterior, WDI (normal and opened eyes; NO, PO), and ST (NO, NC, PO, pillow and closed eyes) before and after the intervention (p<.05). Ankle plantar flexor strength and WDI (PO) were significantly different between groups. Conclusion : Based on the results of this study, DS or SM can be considered as a possibility for selective use according to variables for improving ankle joint function (DFROM, muscle strength, balance).

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.729-736
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• 1997

This paper gives the information of field concrete placed under raining condition. Experimental factors in this study are concrete strength, standard deviation and coefficient of variation. The results are as follows: 1. The strength of field concrete placed under raining condition is not largely dependent on the raining condition. 2. But, the quality of concrete is very critical.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1997년도 사면안정 학술발표회 논문집
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• pp.115-136
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• 1997

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.308-311
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• 2004

Many researchers have reported that adding steel fiber to concrete improved its tensile and flexural strength significantly, but relatively few studies have been made on the compressive behavior of SFRC(steel fiber reinforced concrete). It is still less in case of high strength SFRC. The main objective of this research is to examine the effect of adding steel fiber on the compressive strength of high strength SFRC using fiber reinforcing index$(RI,\;V_f(l/d))$. It was found from the study that compressive strength was noticeably increased in proportion to RI.

• 항공우주시스템공학회지
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• 제15권2호
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• pp.16-25
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• 2021

Reliability of fatigue strength on Aircraft Composites(GFRP) Structures was assessed in this paper. Fatigue strength of GFRP was used through the existing fatigue test data with Monte Carlo method. The S_a-N_f curve of composites fatigue strength was assumed as normal distribution and reliability was analyzed using SSIT model. Fatigue stress was designed IAW ASTM F3114-15 with special safety factor of S_sf=1.2~2.0. Reliability was calculated by analytic method and FORM. Sensitivity for the effect of mean and standard deviation of fatigue strength as well as fatigue stability was evaluated. This result can be usefully applied to reliability and fatigue design for composite structures of light weight aircraft.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.80-83
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• 2008

Diverse researches using vegetation index have been carried out to monitor spring droughts that have frequently occurred since 2000. The strength of the drought monitoring using vegetation index lies in that it can reflect characteristics of satellite images: large area coverage, cyclicity, and promptness. However, vegetation index involve uncertainly caused by diverse factors that affect vegetation stress. In this study, multi-temporal vegetation index is compared with the most representative meteorological drought indices like PSDI, SPI. Based on the results from analyses, usability of vegetation index as a tool of drought analysis is proposed.