• Korean Journal of Social Welfare
• /
• v.62 no.2
• /
• pp.161-185
• /
• 2010

The purpose of this study is to verify the causal relationship between depression and aggressiveness among adolescents. The 4-year longitudinal data collected from 2,670 4th grade elementary school students by the Korean Youth Panel study was used in this study. From the analysis result using the Autoregressive Cross-Lagged Model, the depression and aggressiveness in adolescents were continued from elementary school 4th grade to middle school 7th grade in significant stability. In addition, the previous aggressiveness turned out to have significant positive effect on the later period depression. Similarly, the previous depression had significant effect on the later aggressiveness, but the direction was negative. This means that the adolescents's depression increases as their aggressiveness increases, but as the depression increases, the later aggressiveness of the adolescents decreases. There were no differences between girls and boys within the relationship of these two variables. Finally, the implication derived from the results, the limitation of this study, and suggestion for following studies were presented.

• Journal of the Korean Wood Science and Technology
• /
• v.19 no.1
• /
• pp.71-80
• /
• 1991

This study was carried out to investigate replaceable species with the conventional sounding board sitka spruce. by comparing the dynamic properties such as density, dynamic Young's modulus and internal friction Dynamic Young's modulus. internal friction of longitudinal and radial direction measured in free mass-free boundary condition for facile vibration analysis and measured by forced vibration method. Dynamical properties of four species were measured on squared plate specimen that the four edges were hung vertically by threads and driven magnetically through an iron piece glued on the specimen, by the use of condenser microphone as vibration transducer, and analyzed by FFT analyzer. The results obtained were as follows: 1. Chaldni method using aluminum powder was proper to identify the vibration mode in the plate vibration and it was possible to verify the resornance mode. 2. It was considered that it was necessary to investigate the influence of adhesive part on the plate vibration when the sounding board was made by two or three small board adhesion. 3. It was considered that plate vibration method, which was a superior to the vibration test of beam, was suitable for selecting suounding board because dynamic Young's modulus and internal friction show different order according to longitudinal and radial direction. 4. Paulownia tomentosa Thunb.) Steudel has been considered to be replaceable species with sitka spruce because it has high dynamic Young's modulus compared with low density, low internal friction, and K value of Paulownia tomentosa (Thunb.) Steudel is greater than that of sitka spruce.

• Journal of Korea Water Resources Association
• /
• v.43 no.5
• /
• pp.421-431
• /
• 2010

The hydromorphological structure assessment of the urban streams of Anyang stream, Yangjae stream, Osan stream, Jangsu stream, and Hakui stream 5 years the after close to nature stream restoration work was performed using LAWA (Laenderarbeitsgemeinschaft Wasser) for the investigation of the ecology of streams in urban areas. Based on the results, the effectiveness of stream restoration in urban areas was least in spite that existing various types of stream improvements were applied. Significantly, the grade of the longitudinal, the waterfront, and the use of land nearby waterfront was poorly evaluated. It would be estimated that this trend was due to the discontinuity of the longitudinal, the lack of diversity in waterfront, the installation of facilities nearby waterfront, and was due to the use of hard materials as like stones, blocks, frames, and mats in waterfront. The further studies on the implementation of structural diversity in waterfront should be performed for the improvement of the ecology of urban streams.

• Korean journal of communication and information
• /
• v.37
• /
• pp.171-203
• /
• 2007

Since 2003, Korean government went thru biggest and the most significant 'innovation' communicating the government itself as well as its policies. Following Jo's research design conducted in 2003 (published in 2004), this study adopted a longitudinal design to see how Korean government agencies have been changed by the president 'Noh' administration. The concept, 'encroachment' has been utilized to measure professional level of public relations departments of Korean government agencies. 'Encroachment' occurs when a communication department is managed by a person without proper experience or education/training in the field of public relations. After interviewing public relations managers (19 from central agencies, 16 from local government), encroachment has been found to be 'almost not changed' while, opportunities for professional 'on the job' training increased to a certain level.

• Korean journal of communication and information
• /
• v.32
• /
• pp.7-48
• /
• 2006

The study explores how Korea's major newspaper cover about science news, especially how newspaper frame biotechnology news including new source, news construction ways, coverage trend. The research has a research design to find out coverage pattern or model with frame theory. The result shows that the newspaper has some aspect of frame through out the biotechnology development in the section, theme, source, complexity. The section has been expend to the society and international section, while the theme shift from disease or cancer cure to life itself, genome, or stem cell. In the complexity, the biotechnology news stories have been developed a story plot (event-problem-development-solution). In the climax, the news coverage focuses on the explanation of biotechnology news.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.6
• /
• pp.731-738
• /
• 2013

This paper describes a fault-tolerant driving control strategy for an independent steer-by-wire system in sixwheel-drive/six-wheel-steering vehicles. An algorithm has been designed to realize vehicle maneuverability that is as close as possible to that of non-faulty vehicles by inducing high slip ratio of the wheel through a faulty steer-by-wire system in order to reduce the lateral tire force, which is resistant to the yaw motion. Considering the transition of the longitudinal tire force of a wheel with a faulty steer-by-wire component, the longitudinal tire forces are optimally distributed to the other wheels. Fault-tolerant driving performance has been investigated via computer simulations. Simulation studies show that the proposed algorithm can significantly improve the maneuverability of a vehicle with a faulty steer-by-wire system as compared to the optimal traction distribution method.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.6
• /
• pp.615-624
• /
• 2014

The fin-tube heat exchanger being used for industrial boiler, radiator, refrigerator has been conducted in various studies to improve it's performance. In this study, the characteristics of heat transfer and pressure drop was theoretically analyzed according to longitudinal pitch, location of vortex generator, bump phase and number of the tube surface about the plain fin-tube heat exchanger. The boundary condition for the CFD (Computational Fluid Dynamics) analysis applied with the SST (Shear Stress Transport) turbulence model assumed as the tube surface temperature of 333 K, the inlet air temperature of 423-438 K and the inlet air velocity of 1.5~2.1 m/s. The analysis results indicated that the heat transfer coefficient is not affected highly by the longitudinal pitch, and the heat transfer characteristics was more favorable when the vortex generator was located in front of the tube. Also the bump phase of the tube surface indicated that circle type was more appropriate than serrated type and triangle type in the characteristics of heat transfer and pressure drop, and the sixteen's bump phase of circle type was most favorable.

• Journal of Distribution Science
• /
• v.14 no.10
• /
• pp.109-116
• /
• 2016

Purpose - This study investigates the purchase pattern relating to soybean products in Korea. Specifically, the effect of branding based on a regional name was analyzed in terms of consumer purchase frequencies. The primary purpose of this study is to understand why family characteristics affect product selection for a regional brand in the soybean food category. Research design, data, and methodology - We used data collected by the Rural Development Administration (RDA) of Korea. The RDA has monitored agricultural food consumers for years in order to obtain purchase records. Panel participants live in regions near the capital city of Seoul, Korea. Examining data from January 2010 to May 2016, 667 families were selected for analysis. The final data set was 1,335,402. Each purchase item by each individual family was aggregated to a countable weekly observation. To analyze the data set quantitatively, zero-inflation regression was adopted, which was appropriate to avoid biases from overly dispersed observations. Results - We hypothesized the effects of regional branding from the viewpoint of the family characteristics. The first hypothesis was that the number of children would be positively associated with the purchase of a regional brand of soybean products. The result strongly supported this hypothesis. The second hypothesis was that the number of family members would be negatively associated with the purchase of the soybean products of a regional brand. Based on empirical analysis, we concluded that this hypothesis was partially supported. The third hypothesis was the presence of an interaction effect between the number of children and the family size, which was supported by the results. As a supplementary analysis, we also tested mean-variance differences in terms of categories and regional branding with corporate branding. Conclusion - The results of this study provide insights for regional branding strategies in agricultural food management. This study appears to be one of the seminal studies trying to analyze purchase patterns from longitudinal observations. In addition, this study adopted variables characterizing family lifestyle. This study confirmed that children and family size should be considered when soybean product brands are introduced.

• Korea journal of population studies
• /
• v.34 no.1
• /
• pp.179-198
• /
• 2011

The purpose of this study was to examine relationships between chronic diseases, age, and education in Korea. Logistic regression techniques were used to analyze data from the Korean Longitudinal Study of Ageing (KLoSA), which is a nationally representative sample of Koreans aged 45 years and older. The findings show that probability of having chronic diseases increased with age up to about 74; however, it was reduced for respondents aged 74 years or older. Associations between age and chronic diseases were also differential by education. Less educated Koreans tended to have chronic diseases earlier in their lifetime; however, they were likely to have chronic diseases later in life less than more educated counterparts. The findings suggest that individuals with fewer years of education are at an increased risk of developing chronic diseases earlier in their lifetimes, thereby, leading to a higher rate of mortality at younger ages.

• Journal of Korea Water Resources Association
• /
• v.36 no.4
• /
• pp.673-689
• /
• 2003

Field tests were conducted to investigate characteristics of the transverse mixing and to evaluate the dispersion coefficients in the meandering natural streams. The Sum River and the Cheong-mi Creek, tributaries of Han River, were selected as the test site, and measurements of the hydraulic and dispersion data were performed. In the tracer tests, the radioisotope was used as a tracer and injected into a flow on the instantaneous point source. Using the measured data, the longitudinal and transverse dispersion coefficients were evaluated and compared with the previous studies. The longitudinal dispersion coefficients, which were evaluated by application of the analytical solution, were about 0.5 $m^2$/s at the Sum River and 0.2 $m^2$/s at the Cheong -mi Creek. The transverse dispersion coefficients, which were evaluated by the analytical solution and the moment method, were ranging from 0.01 to 0.06 $m^2$/s for the Sum River and from 0.01 to 0.05 $m^2$/s for the Cheong-mi Creek.