• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.1
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• pp.55-58
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• 2012

By using EEG and HRV, subjects were estimated on their psychological and physiological reaction when reading psychrometric chart in 7 point century font, in an environmental test room in the condition of temperature 25[$^{\circ}C$], relative humidity 50[RH%], air current speed 0.02[m/sec], giving variation in illuminance to 0.1, 300, 600, 1000, 1300 and 1600[lux]. As a result, it was at 1300[lux] that absolute ${\alpha}$ wave, SMR, SDNN were most vitalized, and also both sides ${\alpha}$ wave asymmetry index, SEF50, HRT, stress and fatigue degree were at the lowest. It was found that a certain illuminance which minimizes psychological stress and fatigue degree while enhancing concentration and task achievement stably does exist.

• Korean Journal of Community Nutrition
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• v.18 no.6
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• pp.599-610
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• 2013

This study was carried out to analyze the effect of a diet program for adult women on weight loss, BMI, eating habits, sleeping habits, health related indices. The subjects was 415 participants of the 10 weeks (20 time participation program). The data was collected by basic somatometry and HRV (Heart Rate Variability) / APG (Accelerated Plethysmograph) Analyzer. The average age, height, weight and BMI were 28.6 years, 162.1 cm, 62.8 kg and 23.9 $kg/m^2$, respectively. Their body types by BMI were under weight (1.2%), normal (45.8%), overweight (24.8%), mild obesity (22.7%) and obesity (5.5%). There were significant reductions of average weight (4.6 kg) and average BMI (1.75 $kg/m^2$) on the 10th week. There were positive changes in vascular age (50.4%), stress index (44.6%), fatigue index (43.9%), health index (54.5%) of the subjects during the program. There was a meaningful difference of the average variation for the vascular age, stress index, fatigue index, and health index between two groups; one improving the eating habit and the other did not (p<0.05), and also there was a meaningful difference of the average variation for the fatigue index in both groups improving the sleeping habit (p<0.05), but was not a meaningful difference of the average variation for the vascular age, stress index, and health index between two groups. There was a meaningful difference of the average variation for the vascular age, stress index, fatigue index, and health index between two groups improving both eating and sleeping habit (p<0.05). In conclusion, the weight loss program was effective on the weight loss and BMI reduction and health related indices.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.6
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• pp.77-87
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• 2012

Recently, Load and Resistance Factor Design (LRFD) based on reliability analysis has become a global trend for economical and rational design. In order to implement the LRFD, quantification of uncertainty for load and resistance should be done. The reliability of result relies on input variable, and therefore, it is important to obtain exact uncertainty properties of load and resistance. Since soil stress is the main reason causing the settlement or deformation of ground and load on the underground structure, it is essential to clarify the uncertainty of soil stress distribution for accurately predict the uncertainty of load in LRFD. In this study, laboratory model test on silty sand bed under probabilistic load is performed to observe propagation of upper load uncertainty. The results show that the coefficient of variation (COV) of soil stress are varied depending on location due to non-linear relationship between upper load increment and soil pressure increment. In addition, when the load uncertainty is transmitted through ground, COV is decreased by damping effect.

• Computers and Concrete
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• v.3 no.1
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• pp.17-28
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• 2006

Replacement of actual stress distribution in a reinforced concrete (RC) flexural member with a simpler geometrical shape, which maintains magnitude and location of the resultant compressive force, is an acceptable conceptual trick. This concept was originally perfected for normal strength concrete. In recent years, high strength concrete (HSC) has been introduced and widely used in modern construction. The stress block parameters require updating to account for special features of HSC in the design of flexural members. In future, more varieties of concrete may be developed and a corresponding design procedure of RC flexural members will be required. The usual practice is to conduct large number of experiments on various sizes of specimen and then evolve an empirical relation. This paper presents a numerical procedure through which the stress block parameters can be numerically derived for a given strain ratio variation. The material model for concrete is presented and computational procedure is described. This procedure is illustrated with several variations of strain ratio. The advantages of numerical procedure are that it costs less and it can be used with new material models for any new variety of concrete.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.1
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• pp.21-30
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• 1998

Design parameters which used to analyze the stress distribution on the tank wall were defined to develop the propellant tank and obtain optimal values. 1/4 modeling of total tank was selected to calculate the stress distribution with respect to the variation of the support lug location and the tank wall thickness and 1/2 modeling was selected for the stress distributions with respect to the variation of fuel outlet location. Actually, 350psi was applied as static load and 12 gravity as a dynamic load during launching on the internal tank wall. The structural analysis was done with respect to attaching condition of the tank in the satellite. Also the effect of the variation of the propellant outlet location from $0^{\cire}$ to $25^{\cire}$ on the stress distribution was investigated. The equivalent stress distribution and optimal parameters induced from analysis results of the each condition will be used as the fundamental data to design the propellant tank.

• Anxiety and mood
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• v.8 no.2
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• pp.93-98
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• 2012

Objective : Cortisol, a product of hypothalamus-pituitary-adrenal axis (HPA axis), is one of our defensive mechanisms in response to stress. The level of cortisol in the saliva is a major biomarker of the stress response by HPA axis and shows diurnal variation. We measured salivary cortisol level and its diurnal variation to compare the pattern of changes by degree of burn and Clinician-Administered PTSD Scale (CAPS) score. Methods : We measured the salivary cortisol levels of 37 subjects hospitalized in the burn center at our facility from March to June 2012. Salivary cortisol levels were measured at 6 : 00 AM and at 7 : 00 PM. All subjects were tested for CAPS to evaluate the severity of posttraumatic stress disorder and the Hamilton Depression Rating Scale to evaluate and to control the coexisting depression. Results : Factorial ANOVA test revealed that there was a statistically significant difference in terms of the effect of the interaction between the degree of burn and the patient's CAPS score. Unlike the mild burn group, in the severe burn group, the patients who had a low CAPS score didn't show a normal diurnal variation and the patients who had a high CAPS score showed the normal diurnal variation. After a few months follow up, we found a greater degree of psychiatric complications in severe burn patients that had a lower cortisol stress response. Conclusion : We suppose that the disappearance of the stress response changes in salivary cortisol seen in the severe burn group may be caused by an impaired stress response. Through followed observation of the subjects, this disruption of cortisol response may cause psychiatric problems afterwards.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.50-57
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• 2013

The high temperature thermal attacks in welding can affect the residual stress of a frame for automotive assembly accompanying frame deformation. Also the residual stress can induce the negative effect on durability performance of the automobile. In order to analyze the frame deformation, the simplified test frame which had the similar shape (form) of the real automotive frame was fabricated. The contactless optical 3D scanner was used for the shape difference measurement of the frame between before and after the welding. The FE-model of the test frame was composed and the deformation and residual stress simulation were performed. The simulated results were compared with the measured results for the reference of the frame design following as the variation of welding sequency. The deformation shape of the frame by simulation was in good agreement with that by the experimental measurement. In addition, the optimized welding sequency with reduced deformation after welding could be achieved through these analyses.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.8
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• pp.73-79
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• 2019

The purpose of this study is to analyze the stress variation according to Hitler's residence using EEG data. Hitler's residence, one of the most monumental buildings, is designed as a grand and overbearing space, giving the visitor a sense of psychological pressure when moving from a high space to low space. Based on the above background, this paper constructs Hitler's residence using virtual reality and measure the changes of the beta waves which are known to be related with stress when the floor level moves from high to low space in Hitler's residence built in virtual space. The results of the experiment are as follows; when moving from high to low space, the subjects' stress was high and at the same time brain waves variation was increased greatly due to changes in space.

• Computers and Concrete
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• v.27 no.1
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• pp.73-83
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• 2021

In this article, the mechanical buckling analysis of simply-supported functionally graded plates is carried out using a higher shear deformation theory (HSDT) in conjunction with the stress function method. The proposed formulation is variationally consistent, does not use a shear correction factor and gives rise to a variation of transverse shear stress such that the transverse shear stresses vary parabolically through the thickness satisfying the surface conditions without stress of shear. The properties of the plate are supposed to vary across the thickness according to a simple power law variation in terms of volume fraction of the constituents of the material. Numerical results are obtained to study the influences of the power law index and the geometric ratio on the critical buckling load.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.77-84
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• 2000

In this paper, the stress analysis of the cast iron insert of spent nuclear fuel disposal canister in a deep repository at 500m underground is done for the underground pressure variation. Since the nuclear fuel disposal usually emits much heat and radiation, its careful treatment is required. And so a long term safe repository at a deep bedrock is used. Under this situation, the canister experiences some mechanical external loads such as hydrostatic pressue of underground water, swelling pressure of bentonite, sudden rock movement etc.. Hence, the canister should be designed to withstand these loads. The cast iron insert of the canister mainly supports these loads. Therefore, the stress analysis of the cast iron insert is done to determine the design variables such as the diameter versus length of canister and the number and array type of inner baskets in this paper, The linear static structural analysis is done using the finite element analysis method. And the finite element analysis code, NISA, is used for the computation.