• Journal of the Korean Chemical Society
• /
• v.57 no.1
• /
• pp.147-158
• /
• 2013

This study is to search an optimal model on causal relationships of the motivations to learn and motivation strategy in chemistry education. The participants in this study are consisted of G and I high schools students (487) in Gwangju. They all answered to the questionnaire. Model I is hypothesized to be path model of the mediation between 'self-efficacy, achievement need, and entity theory of intelligence' and 'learning strategy and self-handicapping tendency of motivation strategy' by goal orientation to explore variables of study effecting the motivation strategy. And Model II is hypothesized path model of the mediation between goal orientation and 'learning strategy and self-handicapping tendency' by 'self-efficacy, achievement need, and entity theory' to explore variables of study effecting the motivation strategy. Based on these models, structural equation modeling techniques are used to evaluate for the path model among goal orientation(learning, performance approach, and performance approach goal orientation), self-efficacy, achievement need, entity theory of intelligence, self-handicapping tendency, and learning strategy in chemistry education. As the results, Model II is considered. Goodness-of-fit indexes of this model related modification models are identified and analyzed in phases. And this model is accomplished by correcting the model the fifth time to enhance goodness-of-fit indexes. In this optimal model II-5 (Fig. 3) on causal relationships of the motivations to learn and learning strategy (p

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.339-339
• /
• 1994

It has been reported that Indole-3-carbinol (I3C), a naturally occurring compound In cruclferous vegetables, exerts anticarcinogenic activity In several organs In rodents. The modifying effects of I3C were therefore assessed uging a rat multi-organ carcinogenesis model. A total of 100 male Sprague-Dawley rats were divided Into 3 groups. Animals of groups 1 and 2 were sequentially treated with diethylnitrosamine (DEN; 100 mg/kg b.w., i.p.), N-methylnitrosourea (NNU; 20 mg/kg b.w., 4 times for 2 weeks, i.p), and dihydroxy-di-N-propylnitrosauine (DHPN; 0.1% In d.w. for 2 weeks) for 4 weeks (DMD treatment). Animals of groups 1 and 3 were given the diet of 0.25% I3C for 20 weeks after DMD initiation and then were given basal diet for 28 weeks. All animals were sacrificed at week 24 and 52, respectively. I3C has been clearly demonstrated promoting effects on the development of glutathione S-transferase placental form (GST-P) positive hepatic foci at 24 weeks of the experiment. And I3C also exerted promoting potential In the hepatocellular adenoma (4/14; 29%) and the adenoma (7/14; 50%) of the thyroid gland at 52 weeks of the experiment. Therefore, I3C may promote hepatocarcinogenesis and thyroid tumorigenesis in the rat multi-organ carcinogenesis model.

• The Mathematical Education
• /
• v.40 no.2
• /
• pp.179-194
• /
• 2001

The seventh curriculum put into operation gradually from first-year student in 2000 academic years of elementary school is subject to form and apply a step-wise level curriculum. Mathematics(correspond to junior high school course from 7th school year to 9th school year) should apply a step-wise level curriculum from 7th school year in 2001 academic years. Accordingly, mathematics teachers must diagnose actual conditions of educations, distribution tables of test results, step-wise teaching-studying programs etc. They also make proper plans suitable for actual situations of each school, prepare appropriate teaching materials and aids. I investigated preceding studies planned for preparation of putting into operation of a step-wise level curriculum. It showed that most of the studies were conducted at schools of medium or large scale and studies conducted at schools of small scale was rare. There were 113 small scale middle schools out of total 297 middle schools in Kyongsangbuk-do area in 2000. In this situation, I felt necessities of modeling of a step-wise level curriculum suitable for small scale schools. In this study, I modeled a step-wise level curriculum suitable for small scale middle schools, applied this model to 44 students in M middle school. I modeled two types of curriculum. One is a step-wise level curriculum that execute special supplementation process to students who do not complete 7-가 step successfully. The other is a step-wise level curriculum which is a regular model for a step-wise level of 7-나 step. I carried out an academic achievement test and intimacy test about mathematics before and after the application of the model. In this study, I found out that this model was very effective in academic achievement of students and helpful to declined students in scholarship. In the intimacy test, It was found out that most of the students gained confidence in mathematics, felt less anxiety, formed positive self consciousness. Therefore, I think that this model will be helpful to the application of the seventh step-wise level curriculum.

• Geophysics and Geophysical Exploration
• /
• v.10 no.1
• /
• pp.1-18
• /
• 2007

Non-linear elastic wavefield inversion is a powerful method for estimating elastic parameters for physical constraints that determine subsurface rock and properties. Here, I introduce six elastic-wave velocity models by reconstructing elastic-wave velocity variations from real data and a 2D elastic-wave velocity model. Reflection seismic data information is often decoupled into short and long wavelength components. The local search method has difficulty in estimating the longer wavelength velocity if the starting model is far from the true model, and source frequencies are then changed from lower to higher bands (as in the 'frequency-cascade scheme') to estimate model elastic parameters. Elastic parameters are inverted at each inversion step ('simultaneous mode') with a starting model of linear P- and S-wave velocity trends with depth. Elastic parameters are also derived by inversion in three other modes - using a P- and S-wave velocity basis $('V_P\;V_S\;mode')$; P-impedance and Poisson's ratio basis $('I_P\;Poisson\;mode')$; and P- and S-impedance $('I_P\;I_S\;mode')$. Density values are updated at each elastic inversion step under three assumptions in each mode. By evaluating the accuracy of the inversion for each parameter set for elastic models, it can be concluded that there is no specific difference between the inversion results for the $V_P\;V_S$ mode and the $I_P$ Poisson mode. The same conclusion is expected for the $I_P\;I_S$ mode, too. This gives us a sound basis for full wavelength elastic wavefield inversion.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.4 no.1 s.12
• /
• pp.33-40
• /
• 2004

The objective of this study is to develop single dam operation models for flood control using Fuzzy control technique, which can improve flood controllability. We set control rules by water level and inflow, and developed three models Fuzzy I, II, III according to rule to decide outflow. Fuzzy I model consists of six rules considering only flood control and Fuzzy II model considers the effect of water use by increasing water level at the end of flood control period as well as flood control during the same period. Finally, Fuzzy m is an adaptive model designed to perform multipurpose dam operation for both flood control and water use simultaneously based on a control rules.

• Journal of Power System Engineering
• /
• v.13 no.5
• /
• pp.76-81
• /
• 2009

The fatalities of pedestrian account for about 21.2% of all fatalities at 2007 year in Korea. To reconstruct exactly the accident, it is important to calculate the throw distance of pedestrian in car to pedestrian accident. The frontal shape of SUV vehicle is dissimilar to passenger car and bus, so the trajectory and throw distance of pedestrian by SUV vehicle is not the same of passenger car and bus. The influencing on it can be classified into the factors of vehicle and pedestrian, and road factor. It was analyzed by PC-CRASH for simulation, and SPSS s/w was used for regression analysis. From the simulation results, the maximum impact energy of multi-body of pedestrian was occurred to that of torso body at the same time. And the throw distance increased with the increasing of impact velocity, and decreased with the increasing of impact offset. Also it decreased with the increasing of velocity of pedestrian at accident, and the throw distance of wet road was longer than that of dry road. Finally, the regression analysis model of SUV(Nissan Pathfinder type)vehicle in car to pedestrian accident was as follows; $$disti_i=-0.87-0.11offseti_i+0.69speed_i-4.27height_i+0.004walk_i+0.63wet_i+{\epsilon}_i$$.

• Journal of Electrical Engineering and Technology
• /
• v.7 no.4
• /
• pp.570-575
• /
• 2012

In a wireless communication RF transmitter, the output of a quadrature modulator (QM) is distorted by not only the linear imperfection features such as in/quadrature-phase (I/Q) input gain imbalance, local phase imbalance, and local gain imbalance but also the nonlinear imperfection features such as direct current (DC) offset and mixer nonlinearity related to in-band spurious signal. In this paper, we propose the unified QM model to analyze the combined effects of the linear and nonlinear imperfection features on the performance of the QM. The unified QM model consists of two identical nonlinear systems and modified I/Q inputs based on the two-port nonlinear mixer model. The unified QM model shows that the output signals can be expressed by mixer circuit parameters such as intercept point and gain as well as the imperfection features. The proposed approach is validated by not only simulation but also measurement.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.6 no.3
• /
• pp.210-224
• /
• 2006

A new analytical model for the static I-V characteristics of GaAs MESFET’s under optically controlled conditions in both linear and saturation region is presented in this paper. The novelty of the model lies in characterizing both photovoltaic (external, internal) and photoconductive effects. Deep level traps in the semi insulating GaAs substrate are also included in this model. Finally, effect of backgate voltage on I-V characteristics is explained analytically for the first time in literature. Small signal parameters of GaAs MESFET are derived under both dark and illuminated conditions. Some of the results are compared with reported experimental results to show the validity of the proposed model. Since accurate dc modeling is the key to accurate ac modeling, this model is very useful in the designing of photonic MMIC’s and OEIC’s using GaAs MESFET.

• Korean Journal of Computational Design and Engineering
• /
• v.5 no.2
• /
• pp.175-183
• /
• 2000

Proposed in this paper is a model-bated AFA (automatic feedrate-adjustment) method for maintaining smooth cutting-loads (i.e., cutting-force) during 2D-profile milling. Before the cutting-force model was established, some assumptions were verified through a series of preliminary cutting experiments (The results found that the curving-force was independent of the cutting speed and the cutting action at the cutter bosom). From the data obtained during the main cutting experiments, a “chip-load/cutting-force model”representing the cutting-force as a function of the chip-load (i.e., effective cutting-depth) and a feedrate is proposed. Based on the model. an AFA scheme for maintaining smooth cutting-force by adjusting the feedrate (i.e., F-code) according to the changes in chip-load was proposed. To check the validity of the proposed AFA scheme. another set of cutting experiments was conducted by using feedrate-adjusted NC-data while monitoring the actual machining processes using an accelerometer. The experimental results showed that the proposed AFA-scheme was quite effective.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.830-833
• /
• 2005

SDM(Structural Dynamics Modification) is to improve dynamic characteristics of a structure, more specifically of a base structure, by adding or deleting auxiliary(modifying) structures. In this paper, I will focus on the optimal layout of the stiffeners which are attached to the plate to maximize 1st natural frequency. Recently, a new topology method was proposed by yamazaki. He uses growing and branching tree model. I modified the growing and branching tree model. The method is designated modified tree model. To expand the layout of stiffeners, I will consider non-matching problem. The problem is solved by using local lagrange multiplier without the mesh regeneration. Moreover The CMS(Component mode synthesis) method is employed to reduce the computing time of eigen reanalysis using reduced componet models.