• Economic and Environmental Geology
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• v.19 no.4
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• pp.297-304
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• 1986

Earthquake disaster is dependent upon both site intensity and strength of structures. The higher the strength, structures become more safe, which in turn increases the construction cost. Therefore, it is necessary to decide an optimum design intensity in which the safety is balanced with the cost. Such an optimum design intensity for major man-made structures in Korea is determined in the present study from a simulation model as follows. 1) Hypothetical earthquake time series are generated from the probability distribution to represent appropriately the seismicity of Korea. 2) The strength of structures constructed with a certain design intensity is assumed to exponentially decrease with the elapsed time. The construction cost is also expressed as a function of design intensity. 3) Comparing the seismic intensity generated from the earthquake time series with the strength of structures, the safety of structures is examined. Then the time until the structure is damaged by an earthquake is obtained within the designed life time. 4) The above simulation is iterated several hundred times and hence the mean life time of structures having a certain design intensity is obtained. 5) After all, the optimum design intensity to minimize the annual mean loss, the ratio of construction cost to mean life time, is estimated. The major conclusions obtained from the above simulation model are as follows. 1) Depending upon the designed life time ($T_p$), the optimum design intensities are appeared to be 0. 05-0. 10g for $T_p=50yr$ and 0. 08-0.13g for $T_p=100yr$. 2) According to the sensitivity analysis, the optimum design intensity increases with the rapid strength decrease of structure and decreases with the increase of initial construction cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.805-812
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• 2011

The elderly population has been dramatically increasing over the past years, but most of the population has developed chronic diseases and handicaps due to aging. High-intensity resistance training is one of the most effective ways to improve muscular strength, but it is unclear whether body composition and functional fitness would be increased by high-intensity resistance training. The aim of this investigation was to explore whether 12 weeks of high-intensity training would improve muscular strength, body composition, and functional fitness in women over the age of 70 years. Twenty-four participants were randomly assigned to a high-intensity resistance training group (n=8), a low-intensity resistance training group (n=8), and a control group (n=8). The experimental groups exercised 3 days per week for 12 weeks at a local fitness center. An analysis of variance(ANOVA) with repeated measures was used for analysis. The results showed that there was a significant improvement in agility and muscular strength following the high-intensity resistance training. Moreover, Moreover, %body fat and body fat mass decreased significantly after the 12 weeks of high-intensity resistance training(p<0.05). Based on these results, it was concluded that high-intensity resistance training is efficient for women over the age 70 years in increasing their muscular strength and functional fitness and reducing their total body fat mass.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.5
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• pp.42-50
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• 1991

According as the members and inner and outer plates of the automobile body structure have been thinned their thickness and have become high strength, each part of the body structure has been put more severe stress condition. Therefore, it has been increasingly required to improve the fatigue strength of the spot welded structures. As one of the improving methods for such problem, the author had previously proposed the method of alleviating stress concentration at nugget edge of the spot weld part and improving its fatigue strength [1]. But, because fatigue strength of the spot welded lap joint is influenced by its geometrical and mechanical factors, welding condition and etc., there needs a quantitative and systematic estimation method of them. In this report, by considering nugget edge of the spot weld part of the spot welded lap joint subjected to tensile load to the ligament crack, fatigue strength of various spot welded lap joints was estimated with the stress intensity factor (S.I.F.) K which is fracture mechanical parameter. It is known that evaluation of fatigue strength of the spot welded lap joint by the stress intensity factor (S.I.F.) K is more effective than the maximum stress $(\sigma_{ymax}$) at edge of the spot weld part on the center line of width of the plate.

• Coupled systems mechanics
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• v.7 no.3
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• pp.297-319
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• 2018

In this paper, the vibro-acoustic behaviors of vibrational cylindrical shells are investigated by using structural intensity approach. The reducing interior noise method for vibrating cylindrical shells is proposed by altering and redistributing the structural intensity through changing the damping property of the structure. The concept of proposed novel method is based on the properties of structural intensity distribution on cylindrical shells under different load and damping conditions, which can reflects power flow in the structures. In the study, the modal formulas of structural intensity are developed for the steady state vibration of cylindrical shell structures. The detailed formulas of structural intensity are derived by substituting modal quantities, in which the effect of main parameters such as weight coefficients and distribution functions on structure intensity are analyzed and discussed. Numerical simulations are first carried out based on the structural intensity analytical solutions of modal formulas. Through simulating the coupling vibration and acoustical radiation problems of cylindrical shell, the relationship between vibro-acoustic and structural intensity distribution is derived. We find that for cylindrical shell, by properly arranging damping conditions, the structural intensity can be efficiently changed and further the noise property can be improved. The proposed methodology has important implications and potential applications in the vibration and noise control of fuselage structure.

• The Journal of Korean Academic Society of Nursing Education
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• v.22 no.3
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• pp.345-354
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• 2016

Purpose: The purpose of this study was to determine the effects of a low intensity exercise program with telephone coaching on the physical fitness and physiological index of elderly women who are receiving home visiting health program. Methods: This study was conducted using a non-equivalent control group pretest-posttest design. The participants were 53 senior citizens. The subjects (15) in experimental group 1 performed only a low-intensity exercise program and the subjects (16) in experimental group 2 performed a low intensity exercise program with telephone coaching for 16 weeks. The low intensity exercise program consisted of muscle strength band exercise, stretching, and hand exercise using balls. Results: There were statistical differences in the right grip strength (p=.030), left grip strength (p=.035), raising behind of right arm (p=.046), raising behind of left arm (p=.045), postprandial blood sugar (p=.021), body mass index (p=.029). Conclusion: The low intensity exercise program with telephone coaching is recommended as a physical fitness and physiological index for elderly women in a home visiting health program.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.49-52
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• 2009

This paper aims to evaluate hydration and intensity property of different kind of members and intensity in order to evaluate compressive strength of structural concrete using Joint Separation Test Body(JSTB). In fact it is difficult to test and evaluate already have constructed member. In this case, common method used by construction engineer is that ; Schmidt rebound hammer test, Ultrasonic pulse test, Method of using test specimen previously cast. However, these method to control the structural intensity involve many problem and impossibility to adapt construction. 80, this paper proposes advance an opinion which have proper to examine intensity. has also aims to examine its validity and the plan to make similar environment with structural concrete and joint separation test body in order to verify efficiency assessment and on-site application.

• The Journal of Korean Physical Therapy
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• v.27 no.5
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• pp.339-344
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• 2015

Purpose: The purpose of this study was to determine the effects of high and low resistance exercise using an elastic band on the strength and lymphedema of upper extremity in patients with breast cancer. Methods: Seventeen female patients with breast cancer related lymphedema were randomly allocated to the high (n=9) or low (n=8) resistance exercise group. Both groups participated in the elastic band exercise program three times a week for eight weeks. For the high resistance exercise group (HR), the resistance was gradually increased, while maintaining constant intensity of exercise for the low resistance exercise group (LR). Assessments made include the upper extremity muscle strength and lymphedema before and after training. Results: After the exercise program, the HR showed significantly improved shoulder flexion and elbow flexion strength variation compared to the LR (p<0.05). Upper arm edema rate was significantly decreased in HR (p<0.05), but the difference between the two groups was not significant. Conclusion: These findings suggest that the elastic band exercise helps improve the strength and lymphedema of upper extremity in patients with breast cancer. In particular, high resistance exercise is more effective in improving muscle strength and does not exacerbate lymphedema, rather may improve upper arm edema if it is applied with a low elastic bandage or compression sleeve.

• Structural Engineering and Mechanics
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• v.14 no.2
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• pp.209-221
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• 2002

In this paper a fracture criterion is proposed for cracked cylindrical samples of high-strength prestressing steels of different yield strength. The surface crack is assumed to be semi-elliptical, a geometry very adequate to model sharp defects produced by any subcritical mechanism of cracking: mechanical fatigue, stress-corrosion cracking, hydrogen embrittlement or corrosion fatigue. Two fracture criteria with different meanings are considered: a global (energetic) criterion based on the energy release rate G, and a local (stress) criterion based on the stress intensity factor $K_I$. The advantages and disadvantages of both criteria for engineering design are discussed in this paper on the basis of many experimental results of fracture tests on cracked wires of high-strength prestressing steels of different yield strength and with different degrees of strength anisotropy.

• The Journal of Korean Physical Therapy
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• v.33 no.6
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• pp.292-296
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• 2021

Purpose: The purpose of this study was to investigate the exercise effect of two types of training with a recumbent cycle ergometer on ankle muscle strength (dorsiflexor strength, DFS; dorsiflexor strength/weight, DFS/kg; plantar flexor strength, PFS; and plantar flexor strength/weight, PFS/kg) in healthy male subjects. Methods: Twenty-three healthy males (27.91±8.66 yr) were randomly allocated into two groups (high-intensity interval training (HIIT), and aerobic exercise training (AET) after the first measurement. The subjects were trained for 24 sessions (40 min/rep, three times/week) and ankle strength was measured for a second time. Two-way mixed model analysis of variance (ANOVA) was used to identify significant differences between changes in ankle muscle strength between before and after training (within factors) in the HIIT and AET groups (between factors). The statistical significance level was set at α=0.05. Results: In both HIIT and AET groups, all variables of ankle muscle strength were significantly increased after training compared to before training (p=0.001). However, there were no differences in all variables of ankle strength between the HIIT and AET group (p>0.05). Conclusion: Both types (HIIT and AET) of recumbent cycle exercise training could be effective training methods to increase ankle muscle strength in healthy individuals, and the HIIT type with high intensity and low frequency pedaling could be recommended more to strengthen ankle muscles.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.45-53
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• 2001

Recently some studies have shown that low light intensity followed by final cure at high light intensity may result in a smaller marginal gap and may be no negative effect on material properties. The purpose of this study was to evaluate the influence of the initial cure with low intensity on the shear bond strength of dentin and the microhardness of composite resin. Twenty intact bovine teeth were prepared for shear bond strength test and each tooth sectioned to three specimens. The specimens were randomly divided into three groups according to the light intensity and curing time as follows; Group I. $450mmW/cm^2$ 40sec Group II. $300mmW/cm^2$ 20sec and $600mmW/cm^2$ 20sec Gropu III. $250mmW/cm^2$ 20sec and $450mmW/cm^2$ 20sec. Samples of each group were restored with light-cured composite resin after dentin bonding and then the shear bond strength of each specimen were measured using universal testing machine. Ten resin specimens per group were prepared. After 24 hours, the Vickers microhardness value was measured at the top and bottom surfaces. The result are as follows; 1. Mean value of low initial intensity groups(II, III) were higher than the control group(I) in shear bond strength, but no significant difference could be found. 2. No significant difference could be found between three groups in microhardness.