• Human Ecology Research
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• v.55 no.4
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• pp.441-450
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• 2017

Childcare related studies have focused on the characteristics of care work, policy aspects, user family satisfaction, and job satisfaction of childcare helpers. But there have been few studies on family system characteristics that support childcare givers. Thus, this study conducted on the topic, "How to characterize the family resilience of long-term childcare givers?" The subjects belong to a healthy family support center in U. City, who belong to a group with an income in the top 20 % of about 20 persons working for more than 3 years. In an interview, qualitative questions were used Walsh's family resilience. The results are as follows. First, they had economic hardship, but their family would stand together and build up a family's power based on the couple's faith. They had a family role model based on their parents' family that included inherited maternity qualities from their mother. Second, the flexibility of the family organization changed to autonomous or co-role type and the connectivity. Especially, they appear as a family's leader. Third, their family communication was active, shared-care, responsible and passionate with family affection and understanding. The conclusions results are as follows. Participants were high school graduates as well as had work experience. They were characterized by positive family energy, a family belief system, family-based resources, flexibility, connectivity, open family communication and expression skills. Therefore, it can be suggested that it is necessary to check the family's resilience during an interview for the reliable, long-term supply of human resources for childcare activities.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.509-516
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• 2015

We investigated the reduction leaching process of manganese dioxide ore using black locust as reductant in sulfuric acid solution. The effect of parameters on the leaching efficiency of manganese was the primary focus. Experimental results indicate that manganese leaching efficiency of 97.57% was achieved under the optimal conditions: weight ratio of black locust to manganese dioxide ore (WT) of 4:10, ore particle size of $63{\mu}m$, $1.7mol{\cdot}L^{-1}\;H_2SO_4$, liquid to solid ratio (L/S) of 5:1, leaching time of 8 h, leaching temperature of 368 K and agitation rate of $400r{\cdot}min^{-1}$. The leaching rate of manganese, based on the shrinking core model, was found to be controlled by inner diffusion through the ash/inert layer composed of associated minerals. The activation energy of reductive leaching is $17.81kJ{\cdot}mol^{-1}$. To conclude the reaction mechanism, XRD analysis of leached ore residue indicates manganese compounds disappear; FTIR characterization of leached residue of black locust sawdust shows hemicellulose and cellulose disappear after the leaching process.

• Journal of Digital Contents Society
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• v.19 no.1
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• pp.103-112
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• 2018

In this paper, we propose a method of recognizing emotions using PPG sensor which measures blood flow according to emotion. From the existing PPG signal, we use a method of determining positive emotions and negative emotions in the frequency domain through PSD (Power Spectrum Density). Based on James R. Russell's two-dimensional prototype model, we classify emotions as joy, sadness, irritability, and calmness and examine their association with the magnitude of energy in the frequency domain. It is significant that this study used the same PPG sensor used in wearable devices to measure the top four kinds of emotions in the frequency domain through image experiments. Through the questionnaire, the accuracy, the immersion level according to the individual, the emotional change, and the biofeedback for the image were collected. The proposed method is expected to be various development such as commercial application service using PPG and mobile application prediction service by merging with context information of existing smart phone.

• Earthquakes and Structures
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• v.13 no.5
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• pp.429-442
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• 2017

Dry bridges have been widely applied in the Qinghai-Tibet Railway (QTR) to minimize the thermal disturbance of engineering to the permafrost. However, because the Qinghai-Tibet Plateau is an area with a high potential occurrence of earthquakes, seismic action can easily destroy the dry bridges. Therefore, a three-dimensional numerical model, with consideration of the soil-pile interactions, is established to investigate the thermal characteristics and their impact on the seismic response of the dry bridge in permafrost region along the QTR. The numerical results indicate that there exist significant differences in the lateral displacement, shear force, and bending moment of the piles in different thermal conditions under seismic action. When the active layer become from unfrozen to frozen state, the maximum displacement of the bridge pile reduces, and the locations of the zero and peak values of the shear force and bending moment also change. It is found that although the higher stiffness of frozen soil confines the lateral displacement of the pile, compared with unfrozen soil, it has an adverse effect on the earthquake energy dissipation capacity.

• Advances in nano research
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• v.8 no.2
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• pp.135-148
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• 2020

The incorporation of carbon nanotubes in a polymer matrix makes it possible to obtain nanocomposite materials with exceptional properties. It's in this scientific background that this work was based. There are several theories that deal with the behavior of plates, in this research based on the Mindlin-Reissner theory that takes into account the transversal shear effect, for analysis of the critical buckling load of a reinforced polymer plate with parabolic distribution of carbon nanotubes. The equations of the model are derived and the critical loads of linear and parabolic distribution of carbon nanotubes are obtained. With different disposition of nanotubes of carbon in the polymer matrix, the effects of different parameters such as the volume fractions, the plate geometric ratios and the number of modes on the critical load buckling are analysed and discussed. The results show that the critical buckling load of parabolic distribution is larger than the linear distribution. This variation is attributed to the concentration of reinforcement (CNTs) at the top and bottom faces for the X-CNT type which make the plate more rigid against buckling.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1219-1227
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• 2011

Due to recent changes in living conditions, people who suffer from vascular disease have been increasing. As a result, several kinds of procedures to treat diseases of the blood vessels are being carried out and the epidemiological analysis and interpretation is needed. In this paper, the mechanical behavior of blood vessels based on hyperelastic model were evaluated. The stress distributions in the arterial walls subjected to both normal blood pressure and high blood pressure are studied along with different opening angles representing as the effect of the residual stress. As a result, when applied to residual stress effects in blood vessels to act maximum stress compared to as the absence of residual stress effect about 50% stresses can be reduced. When high blood pressure was the normal blood pressure acting on the blood vessel wall that twice stress can be confirmed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1213-1217
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• 2011

Electric stimulators are used for various treatments, such as for pain relief and to improve rehabilitation in and out of the hospital. However, if the stimulation pulse affects the patient's heart, it can cause critical cardiac disorders such as arrhythmia or ventricular fibrillation. As a result, it must be ensured that the transmission length of the stimulation pulse does not exceed the proper range in the design of an electric stimulator. Furthermore, every anticipated risk factor must be monitored in in-vitro and in-vivo experiments. A new stimulator was designed to supply continuous 0.001 J stimulation pulses at a rate of 60 pulses per second. To evaluate the safety of the new electric stimulator and to measure its energy transfer and pulse transmission length, we built a conduction model that was filled with saline and measured the electric field at various positions in response to real stimulations. In an animal experiment with two pigs, heart disorders were induced by applying electric stimulation to tissues near the heart. These heart disorders were different from the result obtained with 9 V DC stimulation.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.606-611
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• 2007

Pulsation is an inherent phenomenon in reciprocating compressors. It interacts with piping to cause vibrations and performance problems. Indiscriminately connecting to a compressor can be dangerous and cost money in the form of broken equipment and piping, poor performance, inaccurate metering, unwanted vibration, and sometimes noise. Piping connected to a compressor can materially affect the performance and response. To minimize these detrimental effects, reciprocating compressor system should be equipped by pulsation suppression system. This study discusses pressure pulsation phenomena occurred in a reciprocating compressor system. An experiment applied air compressor unit, as pulsating pressure generator, has been done. The compressor was connected sequentially to a snubber model and pressure tank. Sensor probes were placed on the inlet and outlet pipes of snubber. Compressor was driven by a motor controlled by a frequency regulator. The experiment was conducted by adjusting the regulator at 40Hz. General information about an internal gas flow can be achieved by numerical analysis approach. Information of the velocity, pressure and turbulence kinetic energy distribution are presented in this paper. Based on this result, the design improvement might be done.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.46-55
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• 2016

The kinetic analysis of a heavily aluminized cyclotrimethylene-trinitramine(RDX) is conducted using differential scanning calorimetry(DSC), and the Friedman isoconversional method is applied to the DSC experimental data. The pre-exponential factor and activation energy are extracted as a function of the product mass fraction. The extracted kinetic scheme does not assume multiple chemical steps to describe the complex response of energetic materials; instead, a set of multiple Arrhenius factors is constructed based on the local progress of the exothermic reaction. The resulting reaction kinetic scheme is applied to two thermal decomposition tests for validating the reactive flow response of a heavily aluminized RDX. The results support applicability of the present model to practical thermal explosion systems.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.2
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• pp.71-81
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• 2007

One of the most important hydrologic components is evapotranspiration. It is a process by which water is evaporated from moist land surfaces and transpired into atmosphere by plants. There are many methods of estimating evapotranspiration rate and its potential such as the methods of soil-moisture sampling, lysimeter measurements, water balance, energy balance, groundwater fluctuations and evapotranspiration. But it is very difficult to estimate evapotranspiration in terms of regional discrete characteristics of topography and/or vegetation. The evapotranspiration is strongly affected by ground covering vegetation, and the degree of vegetation growth. In order to grasp vegetation condition over a vast study area, NDVI (Normalized Difference Vegetation Indices) calculated from the data obtained from NOAA/AVHRR were utilized. Through multi-regression analysis, we developed a model equation to estimate the evapotranspiration using NDVIs and temperature data.