• Korean Journal of Human Ecology
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• v.12 no.4
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• pp.433-447
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• 2003

Since self-efficacy was suggested by Bandura(1977) as the most important factor that affects human behavior, preceding studies about self-efficacy are frequently related with children, and it is a main stream that only personal factors are chosen as related factors of these studies. Considering we don't have enough studies about family factors that reflect qualitative and relational factors of adolescents' home background, this study was aimed to seize the actual condition of self-efficacy meaning perceived and emotional faith about their own ability. These are our major concerns: 1. What kind of tendency does self-efficacy and appearance stress of adolescents, family functioning show? 2. How strong are relative influences of variables on self-efficacy of adolescents? This study was operated on July and August, 2002, aimed 378 middle school and high school students in Jeon-Nam, Mokpo area. 378 question sheets were used for analysis. Followings are results of this study. First, aimed students' average mark of self-efficacy was 2.09, which meant a normal level. And in low-ranked part, self-control-efficacy was the highest, and confidence task difficulty preference was following. Furthermore, whole self-efficacy showed a little difference from the demographic factor of adolescents. In low-ranked part, however, confidence and self-efficacy showed a somewhat difference. As students grew up, confidence decreased, and male students showed higher self-control-efficacy than female ones. Second, appearance stress and family functioning degree had a strong relation with self-efficacy. Family functioning, had important interrelation not only with whole self-efficacy but also with low-ranked part of self-efficacy. In low-ranked part, self-control-efficacy and task difficulty preference were proportional to the family functioning degree. From these results, we can find that the appearance stress was an actual factor that affected the self-efficacy of adolescents, and their self-efficacy was strongly related with family functioning degree. Accordingly, affirmative emotion in family, harmonic communication among family members and sharing housekeeping works had an immediate influence on elevation of self-efficacy.

• Journal of the Korean Society for Marine Environment & Energy
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• v.1 no.1
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• pp.56-65
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• 1998

An oil spill model, Green Sea Ranger(GSR) based on trajectory and fate modeling of spilt oil behavior is introduced. The various physical models on weathering processes are reviewed and those adopted by GSR are described. A database for currents, which is necessary for the real-time simulation of oil spill, is generated on the south sea of Korea. The real-time prediction of tidal currents in the South Sea of Korea is carried out. Four major constituents (M₂, S₂, K₁, O₁ tide) are employed in the prediction, and those angular speeds and phases are determined from the astronomical arguments. The harmonic constants of the constituents are computed by solving shallow-water tide equations. The GSR has user-freiendly GUI and flexible framework which makes it easy to expand the database for sea environments in Korean coastal waters. The GSR is validated by the simulation of O-Sung oil spill caused by a grounded oil tanker in coastal sea near Maemol-do. The simulated trajectory is compared with observed one and it is shown that the GSR gives reasonable estimation on spilt oil bahavior.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.3
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• pp.116-129
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• 1990

A rational management of water resources in estuary reservoirs necessiates the prediction of water quality. In this study, a multiple box model for the water quality prediction was developed as a tool for the purpose of examining an adequate way to improve and maintain the water quality. Some submodels that are suitable for simulating the mixing behavior of pollutant materials in a lake were considered in this model. The model was appiled for predicting water qualities of Haenam Esturay Reservoir. The result from this study can be summarized as follows : 1.A water quality simulation model that can predict the 10-day mean value of water qualities was developed by adding some submodels that simulate the concentrations of chlorophyll-a, BOD, T-P and T-N to the existing Multiple Box Model representing the mixing and circulating of materials by the hydarulic action. 2.As input data for the model developed, the climatic data including precipitation, solar radiation, temperature, cloudness, wind speed and relative humidity, and the water buget records including the pumping discharge and the releasing discharge by drainage gate were ollected. The hydrologic data for the inflow discharge from the watershed was obtained by simulation with the aid of USDAUL-74/SNUA watershed model. Also the water quality data were measured at streams and the reservoir. 3.As a result of calibration and verification test by using four comonents of water quality such as Chlorophyll-a, BOD, T-P and T-N, it was found that the correlation coefficeints between the observed and the simulated water qualities showed greater than 0.6, therefore the capability of the model to simulate the water quality was proved. 4.The result based on the model application showed that the water quality of the Haenam Estuary Reservoir varies seasonally with the harmonic trend, however the water quality is good in winter and get worse in summer. Also it may be concluded that the current grarde of water quality in the Heanam Esutary Reservoir is ranked as grade 4 suitable only for the agricultutal use.

• Journal of the Korean Society for Marine Environment & Energy
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• v.1 no.2
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• pp.52-59
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• 1998

Many concerns are placed on preservation of coastal environment from the spilled oil contaminant in the coastal area. And the use of computer simulation model to combat with oil spill has come to play mote important role in forecasting the oil spill trajectory so as to protect coastal area and minimize the damage from oil contaminants. The main concerns of this study is how the movements of spilled oil are affected by currents including tidal, oceanic, and wind-driven currents. Especially, in the present paper, the oil spill trajectory can be predicted by a real-time system that allows prediction of circulation and wind field. The harmonic methods are adopted to simulate the tidal currents as well as it can be possible to achieve the wind-field data and oceanic current data from the established database. System performance is illustrated by the simulation of oil spill in the south-eastern coastal area of Korea. Simulation results are compared with the observed one.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.295-298
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• 2006

Experiments in methane-air low strain rate counterflow diffusion flames diluted with nitrogen have been conducted to study the behavior of flame extinction and edge flame oscillation in which lateral conduction heat loss in addition to radiative heat loss could be remarkable at low global strain rates. Onset conditions of edge flame oscillation and flame oscillation modes are also provided with global strain rate. It is seen that flame length is closely relevant to lateral heat loss, and this affects flame extinction and edge flame oscillation. Edge flame oscillations in low strain rate flames are categorized into three: a growing oscillation mode, a decaying oscillation mode, and a harmonic oscillation mode. The regime of flame oscillation is also provided at low strain rate flames.

• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.507-513
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• 1996

Nonlinear optical properties of TeO2-PbO-GeO2 glasses were investigated and their correlation with struc-tural modification was investigated. Third-order nonlinear susceptibility $\chi$, ranged between 5.0$\times$10-13 esu and 10.7$\times$10-13 esu which are approximately 20-40 times larger than that of silica glass. The glass with a composition of 85(80TeO2-20PbO)-15GeO2(mol%) seemed to provide an optimum compromise between $\chi$and the stability against crystallization. Analyses of the Raman spectra suggested that these glasses are mainly composed of [TeO4] tbp, [TeO3]tp and [GeO4] tetrahedral structural units. It was concluded that the positive contribution of Pb2+ with high polarizability to $\chi$ in TeO2-PbO glasses overwhelmed the negative influence due to the structural modification of [TeO4]tbplongrightarrow[TeO3]tp. On the other hand addition of GeO2 in TeO2-PbO-GeO2 glasses resulted in the decrease of $\chi$ values. This behavior was attributed to the formation of [GeO4] polyhedra at the expense of [TeOn] polyhedra and Pb2+ ions which normally sowed a higher contribu-tion to $\chi$ than [GeO4] polyhedra.

• Structural Engineering and Mechanics
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• v.58 no.1
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• pp.59-91
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• 2016

Laminated composite shells are commonly used in various engineering applications including aerospace and marine structures. In this paper, using semi-analytical finite strip method, the buckling behavior of laminated composite deep as well as thick shells of revolution under follower forces which remain normal to the shell is investigated. The stiffness caused by pressure is calculated for the follower forces subjected to external fibers in thick shells. The shell is divided into several closed strips with alignment of their nodal lines in the circumferential direction. The governing equations are derived based on first-order shear deformation theory which accounts for through thickness-shear flexibility. Displacements and rotations in the middle surface of shell are approximated by combining polynomial functions in the meridional direction as well as truncated Fourier series with an appropriate number of harmonic terms in the circumferential direction. The load stiffness matrix which accounts for variation of loads direction will be derived for each strip of the shell. Assembling of these matrices results in global load stiffness matrix which may be un-symmetric. Upon forming linear elastic stiffness matrix called constitutive stiffness matrix, geometric stiffness matrix and load stiffness matrix, the required elements for the second step analysis which is an eigenvalue problem are provided. In this study, different parameter effects are investigated including shell geometry, material properties, and different boundary conditions. Afterwards, the outcomes are compared with other researches. By considering the results of this article, it can be concluded that the deformation-dependent pressure assumption can entail to decrease the calculated buckling load in shells. This characteristic is studied for different examples.

• Journal of the Optical Society of Korea
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• v.18 no.4
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• pp.382-387
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• 2014

An all-reflective, simple noncollinear second harmonic (SH) autocorrelator is described for monitoring the shot-to-shot behavior of ultrashort high-power laser pulses. Two mirrors are used for the dispersion-free splitting of a pulse into two halves. One of the mirrors is able to adjust the delay time and angle between two halves of the laser pulse in a nonlinear crystal. We present the possibility of real-time measurement of the pulse duration, peak intensity (or energy), and the pointing jitters of a laser pulse, by analyzing the spatial profile of the SH autocorrelation signal measured by a CCD camera. The measurement of the shot-to-shot variation of those parameters will be important for the detailed characterization of laser accelerated electrons or protons.

• Journal of the Korean Society for Nondestructive Testing
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• v.13 no.4
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• pp.9-17
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• 1994

It is well recognized recently that ultrasonic technique is one of the most widely used methods of nondestructive evaluation to characterize material properties of nonconventional engineering materials. Therefore it is very important to understand physical phenomenon on propagation behavior of elastic wave in these materials, which is directly associated with ultrasonic signals in the test. In this study, the theoretical analysis on multi-scattering of harmonic elastic wave due to the particulate with interface between matrix and fiber in metal matrix composites(MMCs) was done on the basis of Lax's quasi-crystalline approximation and extinction theorem. SiC particulate (SiCp) reinforced A16061-T6 composite material was chosen for this analysis. From this analysis, frequency dependences of phase velocity and amplitude attenuation of effective plane wave due to the change of volume fraction of SiC particulate were clearly found. It was also shown that the interface condition between matrix and fiber in MMCs gives a direct effect on the variation of phase velocity of plane wave in MMCs.

• Structural Engineering and Mechanics
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• v.45 no.5
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• pp.677-691
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• 2013

A semi-analytical finite strip method is developed for analyzing the post-buckling behavior of rectangular composite laminated plates of arbitrary lay-up subjected to progressive end-shortening in their plane and to normal pressure loading. In this method, all the displacements are postulated by the appropriate harmonic shape functions in the longitudinal direction and polynomial interpolation functions in the transverse direction. Thin or thick plates are assumed and correspondingly the Classical Plate Theory (CPT) or Higher Order Plate Theory (HOPT) is applied. The in-plane transverse deflection is allowed at the loaded ends of the plate, whilst the same deflection at the unloaded edges is either allowed to occur or completely restrained. Geometric non-linearity is introduced in the strain-displacement equations in the manner of the von-Karman assumptions. The formulations of the finite strip methods are based on the concept of the principle of the minimum potential energy. The Newton-Raphson method is used to solve the non-linear equilibrium equations. A number of applications involving isotropic plates, symmetric and unsymmetric cross-ply laminates are described to investigate the through-thickness shearing effects as well as the effect of pressure loading, end-shortening and boundary conditions. The study of the results has revealed that the response of the composite laminated plates is particularly influenced by the application of the Higher Order Plate Theory (HOPT) and normal pressure loading. In the relatively thick plates, the HOPT results have more accuracy than CPT.