• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.444-447
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• 2008

This study is intended to develop a improved version of Cross Impact Analysis Model based on Scaling Theory. In developing the model, we applied the scale transformation technique and regression technique to existing CIA model. Improved CIA model is composed of two sub-models: 'model for impact value measurement,' and 'model for impact value conversion'. We applied a technique which measures data by ordinal scale and then transforms them into interval scale and ratio scale data to CIA model. The accuracy of forecasting and the usability of CIA application have been improved.

• Korean Journal of Child Studies
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• v.30 no.4
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• pp.191-204
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• 2009

The purpose of the current study was to validate the ECBQ (Early Childhood Behavior Questionnaire) scale. Data were collected from the 39 teachers of 338 18- to 36-month-old toddlers (181 boys and 157 girls) in Korea. The ECBQ scale was composed of 201 items (7-point Likert scale) with three dimensions. Reliability of this study was confirmed by Cronbach ${\alpha}$'s for ECBQ subscales ranging from .76 to .81. The results of the Exploratory Factor Analysis identified three dimensions of ECBQ : activity-non activity, extraversion-attention, negative affectivity-transformation. Results of the Confirmatory Factor Analysis supported the hierarchic model. There was a significant relationship between temperament and adjustment of infants. It was concluded that the ECBQ scale in general is acceptable for use in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.82.1-82
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• 2002

• Journal of Korean Academy of Nursing Administration
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• v.9 no.2
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• pp.251-264
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• 2003

Purpose : The expectations are defined as desired expectations in initial SERVQUAL scale(1985, 1988), but in modified SERVQUAL scale(1991), are defined as a feasible ideal point expectations. In assessment of nursing service quality by SERVQUAL scale, the definitions of expectations is important problem. The purpose of this study was to compare the feasible ideal point expectations with the desired expectations in assessment of nursing service quality using SERVQUAL scale. Methods : The subjects were 256 inpatients at 4 general hospitals in Jeju-do(123 for feasible ideal point and 133 for desired). The data were collected by two types of self-reporting questionnaires to measure the feasible ideal point and desired expectations. For data analysis, t-test, multiple regression, and comparative analysis of multiple Rs via Fishers Z transformation. Results : Compared with the SERVQUAL scores, the feasible ideal point expectations better explained the variations of the overall consumer satisfaction($R^2$=O.33) than the desired($R^2$=O.25). Conclusion : The feasible ideal point expectations were more suitable to the assessment of nursing service quality using SERVQUAL scale. It will be need to explore the conceptual definitions of expectations using SERVQUAL scale in different settings. Also, further study needs to be conducted to compare alternative service quality measurement scales.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.838-846
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• 2015

This paper deals with the modified modeling of PV system based on the PSCAD/EMTDC and optimal control method of customer voltages in real distribution system interconnected with the photovoltaic (PV) systems. In order to analyze voltage variation characteristics, the specific modeling of PV system which contains the theory of d-q transformation, current-control algorithm and sinusoidal PWM method is being required. However, the conventional modeling of PV system can only perform the modeling of small-scale active power of less than 60 [kW]. Therefore, this paper presents a modified modeling that can perform the large-scale active power of more than 1 [MW]. And also, this paper proposes the optimal operation method of step voltage regulator (SVR) in order to solve the voltage variation problem when the PV systems are interconnected with the distribution feeders. From the simulation results, it is confirmed that this paper is effective tool for voltage analysis in distribution system with PV systems.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.871-874
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• 1998

It is most important in small signal stability analysis of large scale power systems to compute only the dominant eigenvalues selectively with numerical stability and efficiency. Hessenberg process is numerically very stable and identifies the largest eigenvalues in magnitude. Hence, transformed system matrix must be used with the process. Inverse transformation with complex shift provides high selectivity centered on the shift, but does not possess the desired property of computing the dominant mode first. Thus, advantage of high selectivity of the transformation can be fully utilized only when the complex shift is given close to the dominant eigenvalues. In this paper, complex shift is determined by Fourier transforming the results of dynamic simulation with PTI's PSS/E transient simulation program. The convergence in Hessenberg process is accelerated using the iterative scheme. Overall, a numerically stable and very efficient small signal stability program is obtained. The stability and efficiency of the program has been validated against New England 10-machines 39-bus system and KEPCO system.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.2
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• pp.1-10
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• 2002

This paper presents the new template based human face recognition methods to improve the recognition performance against scale and in-plane rotation variations of face images. To enhance the recognition performance, the templates are generated by linear or nonlinear operation on multiple images including different scales and rotations of faces. As the invariant features to allow for scale and rotation variations of face images, we adopt the affine transformation, the log-polar mapping, and the log-polar image based FFT. The proposed recognition methods are evaluated in terms of the recognition rate and the processing time. Experimental results show that the proposed template based methods lead to higher recognition rate than the single image based one. The affine transformation based face recognition method shows marginally higher recognition rate than those of the log-polar mapping based method and the log-polar image based FFT, while, in the aspect of processing time, the log-polar mapping based method is the fastest one.

• Physical Therapy Korea
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• v.14 no.1
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• pp.37-45
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• 2007

This study was designed to examine, applying Rasch analysis based on item response theory, the questionnaires of the Activities-Specific Balance Confidence (ABC) scale for the elderly. The subjects were 99 institutional older adults and clients of social welfare facilities. The subjects (17 men, 72 women) ranged in age from 65 to 94 years (mean age 76.5 yrs). The Winsteps software was used to assess whether the ABC scale fits the Rasch model, to estimate the score and to refine the rating scale. The results are as follows. Twenty-two subjects were excluded as misfit persons. Four items were found to be misfits and the order of difficulty of the remaining 12 items was rearranged. Their balance confidence is indicated by -.64~1.12 logit, and the transformation formula is score=[(logit score+2.76)/(2.76+3.48)]${\times}$100. The most difficult item was "Walk outside in icy sidewalks" and the easiest item was "Walk around house." In conclusion, the ABC scale for the elderly has been proven reliable and valid. Therefore, it is expected to be used as an effective examination tool for treatment planning and screening for older adults.

• Structural Engineering and Mechanics
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• v.33 no.4
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• pp.429-446
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• 2009

Three-scale homogenization procedure is proposed in this paper to provide estimates of the effective thermal conductivities of porous carbon-carbon textile composites. On each scale - the level of fiber tow (micro-scale), the level of yarns (meso-scale) and the level of laminate (macro-scale) - a two step homogenization procedure based on the Mori-Tanaka averaging scheme is adopted. This involves evaluation of the effective properties first in the absence of pores. In the next step, an ellipsoidal pore is introduced into a new, generally orthotropic, matrix to make provision for the presence of crimp voids and transverse and delamination cracks resulting from the thermal transformation of a polymeric precursor into the carbon matrix. Other sources of imperfections also attributed to the manufacturing processes, including non-uniform texture of the reinforcements, are taken into consideration through the histograms of inclination angles measured along the fiber tow path together with a particular shape of the equivalent ellipsoidal inclusion proposed already in Sko ek (1998). The analysis shows that a reasonable agreement of the numerical predictions with experimental measurements can be achieved.

• Proceedings of the Korea Water Resources Association Conference
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• 1998.05b
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• pp.3-3
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• 1998

In this pressentation it is argued that the heterogeneity of a hydrologic attribute which may seem to be nonstationary at one scale, may become stationary at a larger scale. The fundamental reason for transformation from nonstationarity to stationarity whith the increase in scale is the phenomenon of coarse-graining of the hydrologic processes with increasing scale. Due to the phenomenon of aliasing, a particular scale hydrologic process heterogeneity which is observed as a nonstationary process at that scale, may be observed as a stationary process at a higher(larger) scale whose size is bigger than the stationary extent of the lower scale heterogeneity. As one goes through a hierarchical sequence of larger and larger scales for observations, one would eliminate nonstationarities which emerge at some lower scales at the expense of losing information on the high frequency fluctuations of the lower scale heterogeneities which will no longer be observed at the larger sampling scales. We call this phenimenon as the "coarse-graining in hydrologic observations". In this presentation, it is also argued that by the coarse-graining of hydrologic processes due to the averaging and aliasing operations at increasing scales, the conservation laws corresponging to these scales may still be quite parsimonious, and need not be more complicated as the scales get larger. It is shown that shen a higher(larger) scale process is formed by averaging a lower(smaller) scale process in time or space, the high frequency components of the lower scale process will be eliminated by the averaging operation. Thereby, the resuliiting average hydrologic dynamics, free from the effects of the high frequency components of the lower scale process, can still be quite simple in form. This is demonstrated by means of some recent upscaling work on the solute teansport conservation equation for hetergeneous aquifers. By means of this solute transport example, it is also shown that for the ensemble average form of a hydrologic conservation equation to be equivalent to its volume-average form at any scale, the parameter functions of that conservation equation at the immediately lower scale must be ergodic.