• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.7
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• pp.429-436
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• 2003

This paper presents a new approach for evaluating the transmission marginal loss factors (MLFs) considering the reactive power. Generally, MLFs are represented as the sensitivity of transmission losses, which is computed from the change of the generation at reference bus by the change of the load at the arbitrary bus-i. The conventional evaluation method for MLFs uses the only H matrix, which is a part of jacobian matrix. Therefore, the MLFs computed by the existing method, don't consider the effect of the reactive power, although the transmission losses are a function of the reactive power as well as the active power. To compensate the limits of the existing method for evaluating MLFs, the power factor at the bus-i is introduced for reflecting the effect of the reactive power in the evaluation method of the MLFs. Also, MLFs calculated by the developed method are applied to energy spot markets to reflect the impacts of reactive power. This method is tested with the sample system with 5-bus, and analyzed how much MLFs have an effect on the bidding/offer price, market clearing price(MCP), and settlement in the competitive energy spot market. This paper compared the results of MLFs calculated by the existing and proposed method for the IEEE 14-bus system, and the KEPCO system.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.67-74
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• 1999

Self-Boring Pressuremeter Test(SBPT) is known to be the most effective in-situ test method which can reliably determine consolidation characteristics as well as deformation modules and untrained shear strength. In order to derive the coefficient of consolidation using SBPT results it is necessary to obtain the dissipation behavior from the pore pressure change with time during constant radial strain(generally 10%) and to derive the reliable time factor(Τ) from the analytical method which considers the real in-situ conditions. As previous studies on time factor are based on the assumptions of plane strain condition that the membrane of SBP is infinite, of untrained condition during the expansion of the probe and of elastic soil behavior during consolidation, these analyses can't consider the real boundary conditions and the real soil behaviour. In this study, consolidation analysis similar to real in-situ conditions including test procedure is conducted using finite element program which employs MCC model and Biot theory. Time factor considering the effects of finite membrane length, the total pressure change during consolidation and partial drainage is proposed and compared with previous results.

• Geomechanics and Engineering
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• v.6 no.1
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• pp.17-31
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• 2014

This paper investigates the development of failure surfaces induced by an embankment on soft marine clay deposits and the characteristics of such surfaces through numerical simulations and its comparative study with monitoring results. It is well known that the factor of safety of embankment slopes is closely related to the vertical loading, including the height of the embankment. That is, an increase in the embankment height reduces the factor of safety. However, few studies have examined the relationship between the lateral movement of soft soil beneath the embankment and the factor of safety. In addition, no study has investigated the distribution of the pore pressure coefficient B value along the failure surface. This paper conducts a continuum analysis using finite difference methods to characterize the development of failure surfaces during embankment construction on soft marine clay deposits. The results of the continuum analysis for failure surfaces, stress, displacement, and the factor of safety can be used for the management of embankment construction. In failure mechanism, it has been validated that a large shear displacement causes change of stress and pore pressure along the failure surface. In addition, the pore pressure coefficient B value decreases along the failure surface as the embankment height increases. This means that the rate of change in stress is higher than that in pore pressure.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.37-46
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• 2013

Many factors about the stability for the reservoir embankments is determined when the facility is completed. Therefore the initial design of the embankment is important. Many researchers focused the effect of soil parameters although the cross section greatly affects the stability and can be controlled in design step. The objective of this research is to analysis of the effects for the safety factor of slope and seepage according to change cross-section in embankment. As a result, the quantity of seepage decreased as the gradient of downstream slope decreased and was proportional to the height of embankments. There was a linear relationship between the gradient of slope and the safety factor of slope. However the gradient of slope did not affect other side slope. All in a relationship, regressive equations with a high correlation coefficient were calculated and can be applied the simple estimation method of the stability using the cross-section. As results of analyzing the sensitivity, the friction angle and permeability critically effect for the slope stability and the seepage, respectively. The effect of the slope gradient was similar to major soil properties.

• Journal of Community Nutrition
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• v.4 no.2
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• pp.90-98
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• 2002

This study was performed to examine the dietary and BMI change of Koreans after moving to America and to identify the factors influencing changes of BMI. The subjects were 192 Korean-Americans (men : 86, women : 106) residing in the eastern area of the U.S.A. 1) subjects reported significantly increased consumption frequency in American foods like, low fat milk(p<0.001), cold cereals (p<0.001), whole wheat bread(p<0.001), hamburger(only in males p<0.01) and pizza(only in males p<0.01). Whereas significantly decreased consumption frequency in fish (p<0.05), cooked vegetables(p<0.001), kimchi(p< 0.001) and cooked rice (p<0.001) were reported. 2) It was reported that weight, accordingly BMI were significantly increased (p<0.01). The smoking habit score was significantly decreased for males (p<0.05). 3) Multiple linear regression analysis for BMI change showed that education years in Korea was the most prominent negative factor(p<0.001) in predicting BMI change in America. Elevated frequencies of alcohol, chicken and soft drink in America were also associated with greater increase of BMI. When the length of residence (increase of age) was included in regression model, the increase of age was the most significant factor (p<0.001). Changes of chicken and soda scores were other significant factors.

• Journal of the Korea Safety Management & Science
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• v.16 no.2
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• pp.19-29
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• 2014

Korean societal concern for the train accidents is fast and widely increasing with an ever-increasing demand and use for KTX. Most of these train accidents are inclined to be caused by human error. Experts used to attribute the causes of human error to the defects in various aspects such as technology, organizational system, practices, corporate culture, and/or human resource itself. Among the diverse causes of human error, an important one, even though it was rarely focused, may be the issue of impact of rule or procedure change on human error. Giving attention to the implicit importance of this issue, this study intends to highlight the theme of frequent procedure change in railway driving manual as a critical factor of human error. To attain this purpose mentioned above, dual methodologies were adopted. One is to qualitatively analyze the real cases of procedure change in relevant manuals followed by the incident case(passing the station scheduled to stop) happened lately. Another is to quantitatively perform statistical analysis based on questionnaires received from 224 train drivers. Results show that frequent changes in internal affairs procedure is or may be an important factor causing stress and human error from train drivers.

• Biomedical Science Letters
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• v.11 no.1
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• pp.23-29
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• 2005

Molecular imaging with targeted contrast agents enables tissues to be distinguished by detecting specific cell-surface receptors. In the present study, a ligand-targeted acoustic nanoparticle system is used to identify angioplasty-induced expression of tissue factor by smooth muscle cell within carotid arteries. Pig carotid arteries were overstretched with balloon catheters, treated with tissue factor-targeted or a control nanoparticle system, and imaged with intravascular ultrasound before and after treatment. Tissue factor-targeted emulsion bound and increased the echogenicity and gray-scale levels of overstretched smooth muscle cell within the tunica media, versus no change in contralateral control arteries. Expression of stretch-induced tissue factor in carotid artery media was confirmed by immunohistochemistry. The potential for abnormal thrombogenicity of balloon-injured arteries, as reflected by smooth muscle expression of tissue factor, was imaged using a novel, targeted, nanoparticulate ultrasonic contrast agent.

• Culinary science and hospitality research
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• v.11 no.1
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• pp.87-104
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• 2005

A lifestyle changes according to environment. It appears more in the dietary life connected with the necessities in life. This study is executed empirically through the questionnaire that consists of selection attribute and variables connected with "well-being" that is examined in empirical analysis. It was carried out for 20 days from July 15 to August 5, 2003 with the customers who live in Seoul and the suburbs. With collected data, there were frequency analysis and factor analysis, reliability analysis using SPSS 10.0 packages, and T-test and ANOVA were enforced for the verification of differences between demographic elements with each factor. The result indicates that the inclinations of customers changed from the "well-being" trend have four factors: health consideration factor, food materials factor, cooking factor, and habit factor. And the housewife group shows the great changes in habit factor. In case of the changes according to incomes, the larger income earners tend to consider health more. In conclusion, people came to prefer the healthy Korean style food from the well-being trend.

• Culinary science and hospitality research
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• v.13 no.2
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• pp.22-34
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• 2007

We researched the previous study about the restaurant's physical environment and had made up questionnaires. The purpose of this study is to analyze the effect of physical facilities of family restaurants on customers' satisfaction. The result was as follows: First, customers visited with friends or family irrespective of days $2{\sim}3$ times a month. Second, the physical environment factors of family restaurants were interior design, interior, making atmosphere and exterior. Third, it was the interior factor(0.268), making atmosphere factor(0.353) and exterior factor(0.244) that affected customers' satisfaction in family restaurants(p<0.001). $R^2$ change was 0.659 and the regression model was suited to our study(F=56.475). To increase customers' satisfaction, the physical environment of family restaurants needs remodeling in proper time.

• The Research Journal of the Costume Culture
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• v.19 no.3
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• pp.597-611
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• 2011

The purpose of this study is to propose a design method for one-piece dress patterns with high body fitness through an appearance evaluation of one-piece dress patterns with the application of the 3D Virtual Clothing System known as i-designer. Measures consisted of an optical illusion effect in visual imagery and mutual influence according to a change in the length and princess line, in a silhouette of a one-piece dress. The data was assessed by a t-test and a multi-way ANOVA and factor analysis using SPSS 17.0. The results were as follows; The design of the study pattern was done by modifying the ease of the bust circumference, ease of the abdominal circumference, ease of the hip circumference, the position of the side seam line, and the appearance of horizontality in the hem line, which received a low evaluation in appearance evaluations of a one-piece dress pattern. As a result of analyzing the visual image according to a change in the length and princess line, in the form of a silhouette of a one-piece dress, four factors were selected; the whole-body optical illusion factor, the upper-body optical illusion factor, the bust optical illusion factor, and the lower-body optical illusion factor. As a result of analyzing the effect of the interaction in the visual image according to the design variables, the influence of the main effect was found to be great in each factor. In the upper-body optical illusion factor, a significant difference was not noted in the two-way interaction between the length and the princess line. However, the influence on three-way interaction among the length, princess line, and silhouette was significant.