• Korean Journal of Human Ecology
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• v.20 no.5
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• pp.897-915
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• 2011

The purpose of this study was to investigate the actual conditions and characteristics of weekly and daily child care programs for infants, to provide a basis for the improvement of infant care quality. Weekly and daily curricula of 18 classes for one and two-year-olds classes (9 for each ages) from childcare centers in D city were collected from Nov. 2009 to February 2010. The results are as following: first, classes for one-year-olds plan 6-25 activities and classes for two-year-olds plan 12-30 activities weekly, with differences in the number of weekly activities according to the childcare centers. The number of weekly activities should be planned considering infants' interest as well as educational continuity of the activities. Second, the investigation of daily activities showed that the routine activities planned for one-year-olds were for total of 310-600 minutes and for two-year-olds 310-540 minutes. Among these, on average of 66% of the time was planned for everyday life such as eating and napping. The rest of time was dedicated to indoor and outdoor free play. However a few centers allocated more time for group activities according to subjects compared to free play. A curriculum composed of group activities ignoring infants' individual developmental differences should not be encouraged. Last, the results of cluster analyses on weekly and daily curricula in terms of the number of activities and time, duration, number of group activities and time showed that curricula for infants could be characterized into two types: "free play" and "group activity" curricula.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.104-111
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• 2012

In this paper, we propose a novel method to improve the performance of the improved minima controlled recursive averaging (IMCRA). From an examination for various noise environment, it is shown that the IMCRA has a fundamental drawback for the noise power estimate at the offset region of continuity speech signals. Espectially, it is difficult to obtain the robust estimates of the noise power in non-stationary noisy environments that is rapidly changed the spectral characteristics such as babble noise. To overcome the drawback, we apply the global speech absence probability (GSAP) conditioned on both a priori SNR and a posteriori SNR to the speech detection algorithm of IMCRA. With the performance criteria of the ITU-T P.862 perceptual evaluation of speech quality (PESQ) and a composite measure test, we show that the proposed algorithm yields better results compared to the conventional IMCRA-based scheme under various noise environments. In particular, in the case of babble 5 dB, the proposed method produced a remarkable improvement compared to the IMCRA ( PESQ = 0.026, composite measure = 0.029 ).

• Korean Journal of Construction Engineering and Management
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• v.17 no.4
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• pp.20-27
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• 2016

Emergency and evacuation planning is critical to reduce potential loss of life from flooding. In order to develop evacuation plans, emergency managers and decision makers require estimates of probable inundation areas and times of inundation. In this paper, we present an agent-based modeling approach that incorporates in a hydrodynamic model to estimate both of these properties. A case study is conducted modeling the failure of a dam located in Andong, South Korea. We estimate flood travel times for Manning's roughness coefficients and discharge using a coupling of the continuity equation and Manning's equation. Using the output from the hydrodynamic model and the flood travel times, the agent-based model produces flood inundation maps at each time interval. The model estimates that for two-thirds of the Andong region the time of inundation is estimated to be slightly less than three minutes. The results of this study can be used to in the development of emergency and evacuation planning for the region.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.2
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• pp.94-100
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• 2013

A convergent-divergent nozzle or venturi nozzle has been used to accelerate the wind speed at its throat. The wind speed at the throat is inversely proportional to its area according to the continuity equation. In this numerical study, an airflow phenomena in the venturi system placed at a vertical structure was investigated to understand the vortex effect occurred at the rear-side of the vertical structure on the air speed increment at the throat of the venturi system. For this study, a venturi system sized by $20(m){\times}20(m){\times}6(m)$ was modelled and the area ratio(AR) of the model venturi was 2.86. To see the vortex effect on the air flow acceleration in the venturi throat, two different boundary conditions was defined From the study, it was found that the pressure coefficient(CP) of the venturi system with the vortex formed at the exit of the venturi was about 2.5times of the CP of the venturi system without the vortex effect. The velocity increment rate of the venturi system with the vortex was 61% but 9.5% only at the venturi system without the vortex. Conclusively, it can be said that the venturi system installed in a vertical structure has very positive effect on the flow acceleration at its throat due to the vortex formed at the rear-side of the vertical structure.

• Journal of Educational Research in Mathematics
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• v.18 no.2
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• pp.201-221
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• 2008

This study discusses how the humanity mathematics education can be realized in practice. The essence of mathematical concept is gradually disclosed revealing the ambiguities in the concept currently accepted and clarifying them. Historical development of mathematical concepts has progressed as such, exemplified with the group-theoretical thought and continuous function. In learning of mathematical concepts, thus, students have to recognize, reveal and clarify the ambiguities that intuitive and context-dependent definitions in school mathematics have. We present the process of improvement of definitions of a tangent and a polygon in school mathematics as examples. In the process, students may recognize the limitations of their thoughts and reform them with feelings of humility and satisfaction. Therefore this learning process would contribute to cultivating students' minds as the humanity mathematics education pursues.

• Journal of the Society of Disaster Information
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• v.11 no.3
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• pp.421-428
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• 2015

This study reviewed the occurrence and cases of disasters in the rural areas with an aim to establish safety village in rural areas. It also identified the occurrence of disasters and problems with on-site inspections of 6 villages which had suffered from disaster, and figured out people's awareness of and requirements for disaster and safety in rural areas by conducting surveys on the awareness of the residents. The research concluded as follows: First, it is required to come up with the measures to increase the interest of the rural residents in disaster and safety. Second, it is required to develop customized content to improve the residents' awareness of disaster prevention through continued education and trainings. Third, it is required to have legal/institutional grounds for continuous budget support and maintaining the continuity of business. Fourth, it is required to equally establish the structural and non-structural measures to make safety village.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.775-786
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• 2002

A Mixed Volume and Boundary Integral Equation Method is applied for the effective analysis of elastic wave scattering problems and plane elastostatic problems in unbounded solids containing general anisotropic inclusions and voids or isotropic inclusions. It should be noted that this newly developed numerical method does not require the Green's function for anisotropic inclusions to solve this class of problems since only Green's function for the unbounded isotropic matrix is involved in their formulation for the analysis. This new method can also be applied to general two-dimensional elastodynamic and elastostatic problems with arbitrary shapes and number of anisotropic inclusions and voids or isotropic inclusions. In the formulation of this method, the continuity condition at each interface is automatically satisfied, and in contrast to finite element methods, where the full domain needs to be discretized, this method requires discretization of the inclusions only. Finally, this method takes full advantage of the pre- and post-processing capabilities developed in FEM and BIEM. Through the analysis of plane elastostatic problems in unbounded isotropic matrix with orthotropic inclusions and voids or isotropic inclusions, and the analysis of plane wave scattering problems in unbounded isotropic matrix with isotropic inclusions and voids, it will be established that this new method is very accurate and effective for solving plane wave scattering problems and plane elastic problems in unbounded solids containing general anisotropic inclusions and voids/cracks or isotropic inclusions.

• Journal of Yeungnam Medical Science
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• v.12 no.1
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• pp.75-83
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• 1995

Even though phototherapy is an effective means of treating hyperbilirubinemia, adequate binocular shields are essential to prevent light hazard of retina during phototherapy. The phototherapy to young albino rabbits was performed under various conditions; exposured for 12, 24, and 48 hours, continuity or intermittence of irradiation, and use of shields. Although there was no definite pathologic change in indirect ophthalmoscopic examination, severe damage was seen at electron microscopic level. In all experimental groups, swelling and edema of photoreceptor were seen at right after phototherapy. Futhermore, more severe damage was seen in case of intermittent irradiated group and prolong exposed group. In mydriatic eyes, severity of damage was similiar to non mydriatic eyes, but area of retinal damage was more extensive than non-mydriatic eyes. In control group which was protected by binocular shields during phototherapy, no significant abnormality was found.

• Geomechanics and Engineering
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• v.6 no.2
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• pp.153-172
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• 2014

In order to investigate the effect of different perforation angles (the angle between the perforation direction and the maximum horizontal principal stress) on the fracture initiation and propagation during hydraulic fracturing of highly deviated well in oil & gas saturated formation, laboratory experiments of the hydraulic fracturing had been carried out on the basis of non-dimensional similar criteria by using 400^3 $mm^3$ cement cubes. A plane fracture can be produced when the perforations are placed in the direction of the maximum horizontal principal stress. When the perforation angle is $45^{\circ}$, the fractures firstly initiate from the perforations at the upper side of the wellbore, and then turn to the maximum horizontal principal stress direction. When the well deviation angle and perforation angle are both between $45^{\circ}$ and $90^{\circ}$, the fractures hardly initiate from the perforations at the lower side of the wellbore. Well azimuth (the angle between the wellbore axis and the maximum horizontal principal stress) has a little influence on the fracture geometries; however it mainly increases the fracture roughness, fracture continuity and the number of secondary fractures, and also increases the fracture initiation and propagation pressure. Oriented perforating technology should be applied in highly deviated well to obtain a single plane fracture. If the well deviation angle is smaller, the fractures may link up.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.5-17
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• 2018

The standardized eddy covariance flux data processing in KoFlux has been updated, and its database has been amended accordingly. KoFlux data users have not been informed properly regarding these changes and the likely impacts on their analyses. In this paper, we have documented how the current structure of data processing in KoFlux has been established through the changes and improvements to ensure transparency, reliability and usability of the KoFlux database. Due to increasing diversity and complexity of flux site instrumentation and organization, we have re-implemented the previously ignored or simplified procedures in data processing (e.g., frequency response correction, stationarity test), and added new methods for $CH_4$ flux gap-filling and $CO_2$ flux correction and partitioning. To evaluate the effects of the changes, we processed the data measured at a flat and homogeneous paddy field (i.e., HPK) and a deciduous forest in complex and heterogeneous topography (i.e., GDK), and quantified the differences. Based on the results from our overall assessment, it is confirmed that (1) the frequency response correction (HPK: 11~18% of biases for annually integrated values, GDK: 6~10%) and the stationarity test (HPK: 4~19% of biases for annually integrated values, GDK: 9~23%) are important for quality control and (2) the minimization of the missing data and the choice of the appropriate driver (rather than the choice of the gap-filling method) are important to reduce the uncertainty in gap-filled fluxes. These results suggest the future directions for the data processing technology development to ensure the continuity of the long-term KoFlux database.