• Korean Journal of Child Studies
• /
• v.35 no.5
• /
• pp.1-14
• /
• 2014

This study explored the determinants of smartphone addiction among mothers of infants, focusing on their socio-demographic characteristics, parental stress, and parental knowledge. A total 220 mothers of infants were surveyed and the collected data were analyzed by binary logistic regression. A considerable percentage (16%) of mothers of infants were observed to be at a risk of smartphone addiction, which was significantly higher than the percentage (8%) of adult population at risk of smartphone addiction reported by the Korean government. Parental stress from dysfunctional parent-child relationships was a risk factor and parental knowledge about infant development was observed to be a protective factor when it came to the smartphone addiction of mothers' with infants. However, socio-demographic characteristics (number of children, age, education, family income, and job) did not have statistically significant associations with their smartphone addiction.

• Korean Journal of Child Studies
• /
• v.28 no.5
• /
• pp.73-89
• /
• 2007

The purpose of this study was to develop a reliable and valid instrument to assess Korean teachers' strategies for addressing challenging behaviors of preschoolers. The Teacher Strategy Questionnaire(TSQ) consisting of 34 items was developed with three theoretically driven factors(positive proactive, positive reactive, and negative reactive strategies). Participants were 238 preschool and daycare center teachers who responded to the TSQ. Validity and reliability of the TSQ were explored using Cronbach's $\alpha$, item analysis, and factor analyses. The reliability of the TSQ was relatively high, ranging from .74 to .85. No item needed to be eliminated. Among the three pre-structured factors of the TSQ, one positive proactive factor was identified as having two innate factors.

• Journal of Ocean Engineering and Technology
• /
• v.22 no.6
• /
• pp.1-6
• /
• 2008

Anchors have been commonly used to as foundation systems of the structures that require the uplift resistance. Recently anchors have been used in ocean sediment for mooring systems to stabilizeoffshore structures. In the saturated clayey soil however suction developed between the soil and andchor and affects the uplift capacity of anchor. To estimate the uplift capacity of the andchor accurately, the failure mechanisms of the andchor by the uplift force should also be correctly assumed. The uplift capacity is usually expressed in terms of breakout factors with respect to embedment ratio. In this paper, a two-dimensional plane strain numerical investigation into the vertical uplift capacity of a plate andchor in a clayey soil is described. The breakout factor against their corresponding values of embedment ratio was calculated and plotted along a single curve. The modes of failure mechanism at shallow and deep andchors are also presented.

• Journal of Institute of Control, Robotics and Systems
• /
• v.4 no.4
• /
• pp.517-524
• /
• 1998

This paper discusses the development of a reactive power controller using digital signal processing. Digital Signal Processing is the technique of using digital devices to Process continuous signals or data, often in real-time. And DSP algorithms are associated with a discrete time interval between input samples. When one designs a digital filter, one can use a Laplace transform to determine the continuous time frequency response. The corresponding discrete time transform is called Z transform and depends upon discrete samples of the input spaced equally in time. The objectives of this paper are to minimize real power losses and improve the power factor of a given system. Also, the implementation of a direct-form non recursive filter on the TMS320C31 has been described. The application of this microprocessor-based controller using DSP on test system reveals its numerous advantages. Performance and features of the controller for the reactive power control are analyzed.

• Journal of Environmental Science International
• /
• v.20 no.3
• /
• pp.373-384
• /
• 2011

This study aims at the examination of the relative characteristics of discharge and water quality in river basins using statistical methods. For it, water quality and discharge data was collected in observed stations of Nakdong river and carried out correlation analysis, regression analysis, factor analysis and cluster analysis. And it was investigated the applicability of water quality prediction using Nearest-neighbor method. As a result, it grasped a trenditional characteristics and mutual relations between discharge an water quality data. Therefore, this results were suggested the comprehensive data and methods for a management of water quality, effective operation and policy development in Nakdong river basin.

• Journal of Families and Better Life
• /
• v.16 no.4
• /
• pp.155-166
• /
• 1998

The purpose of this study was to develop ' the Behavior Problem Scale for Children and Adolescence' The 518 subjects were selected from 5th and 6th grades of elementary schools and first and second grades of middle schools in Pusan. Statistics used for data analysis were χ2 cramer's V, factor analysis multi-regression Pearson's r, Cronbach's a. The major finding of this study were as follows 1) 80 items of the 159 item scale were acceptable through item discriminant method The discriminant coefficients of the items(Cramer's V) ranged from .48 to .81. 2) 6 factors(shyness aggression hyperactivity withdrawal anxious immature) extracted from factor analysis,. Multi-regression analysis conducted to reduce the length of scale have drawn 42 items for 'the Behavior Problem Scale Children and Adolescence' 3) Reliability coefficients(Cronbach's a) of this scale was 94.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.81-82
• /
• 2008

본 논문은 국책사업으로 진행되는 한국형EMS(K-EMS : Korean Energy Management System)의 응용프로그램 중 하나인 TLF(Transmission Loss Factor)산정 프로그램에 대해 중요 알고리즘과 전반적인 기능에 대해서 기술하였다.

• Journal of the Korean Home Economics Association
• /
• v.31 no.2
• /
• pp.41-54
• /
• 1993

The purpose of this study was to develop 「the Self-Esteem Inventory」(SEI). The 2,451 subjects were selected randomly from 4, 5 and 6th grades of elementary schools and the first and second grades of middle schools in the city to Taegu. Factor analysis, Pearson's r, Cramer's V, and Cronbach's αwere conducted for the statistical analysis. It was found that (1) Factor analysis showed that SEI consisted of 4 factors (global, social-peers, home-parents, and school-academics), (2) The discriminant coefficients of the items (Cramer's V)ranged from 0.25 to 0.71, (3) The reliability coefficients of the scale (Cronbach's α) ranged from 0.69 to 0.84, and (4) The correlation coeffcients of the SEI with RSES and CSEI ranged from 0.47 to 0.78.

• Geomechanics and Engineering
• /
• v.15 no.1
• /
• pp.669-676
• /
• 2018

The "pseudo-wedge" failure is a name for a complex instability occurring at the Sarcheshmeh open-pit mine (Iran). The pseudo-wedge failure contains both the rock bridge failure and sliding along pre-existing discontinuities. In this paper, a cross section of the failure area was first modeled using a bonded-particle method. The results indicated development of tensile cracks at the slope toe which explains the freedom of pseudo-wedge blocks to slide. Then, a three-dimensional discrete element method was used to perform a block analysis of the instability. The technique of shear strength reduction was used to calculate the factor of safety. Finally, the influence of geometrical characteristics of the mine wall on the pseudo-wedge failure was investigated. The safety factor significantly increases as the dip and dip direction of the wall decrease, and reaches an acceptable value with a 10-degree decrease of them.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.236-241
• /
• 2000

In this paper, transparent dynamic photoelastic experimental hybrid method for propagating cracks in orthotropic material is developed. Using transparent dynamic photoelastic experimental hybrid method, we can obtain stress intensity factor and separate the stress components from only isochromatic fringe patterns without using isoclinics. It is certified that the dynamic photoelastic experimental hybrid method is very useful for the problems of the dynamic tincture mechanics.