• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1777-1783
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• 2013

Parshall flume is more practical one of hydraulic structures for measuring flowrate in open channels and also has more advantages when the magnitude of flow velocity is relatively lower or much more sediments are brought from upstream. International Organization for Standardization (ISO) has suggested the empirical formulas standardized by the sizes and dimensions of Parshall flume. However, the related studies using the numerical simulations and experiments are relatively rare. Therefore, in this study, it was examined whether the numerical simulation was adequacy for reproducing the hydraulic characteristics of Parshall flume as much as laboratory experiments by comparing the results from numerical simulations and empirical equation. And for arbitrary Parshall flume, that is unlisted in the ISO standards due to environmental conditions, constructional difficulties etc, thus, the hydraulic experiments should be conducted to obtain the empirical formulas for it, the results from numerical simulations were compared with those of laboratory experiments. Consequently, it was convinced that the numerical simulation about Parshall flume was simulated appropriately instead of experimental approach. And the dimensionless discharge equation of arbitrary ones was suggested using the results of numerical simulations, and the equation was validated by comparing with laboratory experimental results showing the maximum relative error of 2.3%. If the actual topography, the shape of inlet and submerged flow, which is excluded in this study, were carefully considered, it would be possible to supply a simple empirical discharge equation based on numerical results. Also, it can replete hard works for hydraulic experiment being error-prone with complex procedures to a minimum of economic effort.

• Journal of Preventive Medicine and Public Health
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• v.37 no.1
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• pp.59-71
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• 2004

Objectives: This study aimed to measure the disability weights for the Korean Burden of Disease study, and to compare them with those adopted in the Australian study to examine the validity and describe the distinctive features. Methods : The standardized valuation protocol was developed from the Global Burden of Disease (GBD) study and the Dutch Disability Weights study. Disability weights were measured for 123 diseases of the Korean version of Disease Classification by three panels of 10 medical doctors each. Then, overall distribution, correlation coefficients, difference by each disease, and mean of differences by disease group were analyzed for comparison of disability weights between the Korean and Australian studies. Results : Korean disability weights ranged from 0.037 to 0.927. While the rank correlation coefficient was moderate to high ($r_s$=0.68), Korean disability weights were higher than the corresponding Australian ones in 79.7% of the 118 diseases. Of these, war, leprosy, and most injuries showed the biggest differences. On the contrary, many infectious and parasitic diseases comprised the greater part of diseases of which Korean disability weights were lower. The mean of the differ ences was the highest in injuries of GBD disease groups, and in cardiovascular disease, injuries, and malignant neoplasm of the Korean disease category. Conclusions : Korean disability weights were found to be valid on the basis of overall distribution pattern and correlation, and are expected to be used as basic data for broadening the scope of burden of disease study. However, some distinctive features still remain to be explored in following studies.

• Journal of Distribution Science
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• v.12 no.10
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• pp.123-128
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• 2014

Purpose - The purpose of the study is to reexamine the price fairness as practiced by low cost airlines, as a consumer has to experience such inconveniences as inferior airport transportation, extra fees on in-flight meals, and non-negotiable seats, and consumers evaluate such experiences keeping in mind their total costs. This evaluation includes price fairness and allows a reasonable and overall consideration of factors of low cost airlines. It tries to set up a measurement of the indicators consumers' perceptions of price fairness academically as it adapts price fairness to airline services which are renowned for price volatility. Research design, data, and methodology - The research proposes an alternative pricing strategy for the long term profit of low cost airlines after going over conflicts between the traditional theory of consumers' price perception mechanism and flexible fair policy of low cost airlines. It was meaningful when it relates to the early stage of the business, while it enhances the risks relating to the long term survival of low cost airlines. In addition, it is significant as it highlights the negative influences on consumers' perceptions of price fairness, as low cost airlines run on extremely low cost perspectives. Results - The results of the research provide insight into four perspectives, as consumers' perceptions of price fairness are influenced by the frequency and range of price changes and services. The first perspective is that it would lead to positive price evaluation when a low cost airline cuts prices frequently with little changes than one big change. It also would lead to the same result when it comes to necessary services. The second perspective is that one big increase of price would rather undermine the negative aspects of price changes than those of several smaller ones. The third perspective is that additional services would be good to consumers' perceptions of price fairness as compared to discount benefits with respect to the cost. Finally, a low cost airline should consider that consumers will change airlines or defer their flight schedule if the flight fares increase beyond their limits. Conclusions - Low cost airlines should reconsider their pricing policies for services that were provided free earlier. A consumer would not like discount benefits when made to pay for services that were, for long, free of charge. If a low cost airline can provide services with no charge, it should improve volumes if the costs are standardized and, moreover, should consider the charging fees. Alternatively, a consumer can choose between services and fair discount. Low cost airlines are implementing sales promotion strategies, as the competition is more intense than it used to be. In these days, they should regard services over sales promotion, as consumers may prefer to spend money on good premium services. Some differentiation in services could create a good market position for the airlines and, hence, good financial performance.

• Journal of Korea Water Resources Association
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• v.41 no.4
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• pp.405-412
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• 2008

Rainfall quantiles were estimated by applying the FORGEX method. The circle network and two elliptical ones with the ratios of 1 to 1.5 and 1 to 2.0 were used and compared to find appropriate one for rainfall data. Annual maximum data were collected from 376 sites and standardized by the median. The networks were organized from the subject sites and then pooled and netmax data were collected from each network. Then, the growth curves and quantiles were estimated. When the subject site had small differences of quantiles from index flood method and at-site frequency analysis, those of the estimated quantiles from circle and elliptical networks were small. In contrast, the sites where the quantile differences are big have big differences of quantiles from circle and elliptical networks. The estimated quantiles from the elliptical network are more accurate than those from the circle network, because the ellipse network contains more sites in South Korea. Moreover, the ellipse with ratio of 1 to 2.0 shows closer quantiles to those from index flood method than one with ratio of 1 to 1.5. It is, therefore, found that the FORGEX method with 1 to 2.0 ellipse network is appropriate regional frequency analysis in South Korea.

• Imaging Science in Dentistry
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• v.40 no.1
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• pp.39-44
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• 2010

Purpose : We want to identify the appearance of the buccolingual root dilaceration teeth in the panoramic views and specify the characteristics of these teeth. Materials and Methods : One thousand-six patients were examined on the basis of both panoramic and CT image criteria. We diagnosed and excluded certain teeth from the samples; both prosthodontic or pathologic lesion appearing teeth and mesiodistally dilacerated ones. We meticulously discerned buccolingually dilacerated teeth in the CT images and total 48 samples were selected. The degree of severity in dilaceration was standardized by 2 types of criteria. The samples were differentiated into 3 groups and again categorized into six types showing from the panoramic views: irregular view on the root apex area, clear blunt on the root tip, stepping on root tip, double lamina dura or double tip, arrow-target shaped root, bull's eye, normal view. Results : The types of teeth selected from total 48 buccolingual root dilaceration samples were mandibular first and second molar, premolars, canines, and lateral incisors. The direction of dilaceration was an even percentage to each buccal and lingual side for most selected teeth, however, that of both canines and lateral incisors were directed in almost a buccal side. In the panoramic views, the root types of the buccolingually dilacerated teeth were irregular view on the root apex area, clear blunt on the root tip, stepping on root tip and normal types were almost always normal view. The more severity in dilareated degree, the more chances of observation in the panoramic views were clear blunt on the root tip and stepping on root tip. Conclusion : As observed in the shape of stepping on root tip or double lamina dura in the panoramic views, there can be much more probability to diagnose as a buccolingually dilacerated root.

• Journal of the HCI Society of Korea
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• v.3 no.1
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• pp.39-47
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• 2008

A mobile phone became the practical necessities of Chinese life that can not be explained without a mobile phone as it is rapidly popularized in China in recent years. As income increases due to economic growth, so did desire to buy better products. And This desire has made consumers in China more concerned about design and consequently leads to artistic design of a mobile phone. And also this trend is getting linked to people's personalisation in that people prefer rather to choose products they like than standardized ones in the middle of a variety of cultural inflows. This study mainly focuses on the development of the characterized mobile phone with a high class brand by use of traditional elements and of design identity of a mobile phone with Chines style that is well harmonized with cultural and personalized identity as consumers' preferences are quite different from each other depending on each country's culture. For this, this study investigates traditional elements such as patterns, colors and characters as well as development and features of the mobile phone design. This will also lead to the development of a mobile phone with traditional elements of China by studying utilization of design with traditional patterns. To do this, the study analyzes to research traditional patterns(Dragon, Phoenix, Peony, Lotus Flower), colors(Red, Yellow, Blue, Black, White) and historical origin and concept of characters. The study also looks into instances and personalisation of mobile phone design by analyzing literatures.

• Journal of Biosystems Engineering
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• v.38 no.2
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• pp.138-148
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• 2013

Purpose: Determining an appropriate path is a top priority in order for a robot to maneuver in a dynamically efficient way especially in a pick-and-place task. In a non-standardized work environment, current robot arm executes its motion based on the kinematic displacements of joint variables, though resulting motion is not dynamically optimal. In this research we suggest analyzing and applying motion patterns of the human arm as an alternative to perform near optimum motion trajectory for arbitrary pick-and-place tasks. Methods: Since the motion of a human arm is very complicated and diverse, it was simplified into two links: one from the shoulder to the elbow, and the other from the elbow to the hand. Motion patterns were then divided into horizontal and vertical components and further analyzed using kinematic and dynamic methods. The kinematic analysis was performed based on the D-H parameters and the dynamic analysis was carried out to calculate various parameters such as velocity, acceleration, torque, and energy using the Newton-Euler equation of motion and Lagrange's equation. In an attempt to assess the efficacy of the analyzed human motion pattern it was compared to the virtual motion pattern created by the joint interpolation method. Results: To demonstrate the efficacy of the human arm motion mechanical and dynamical analyses were performed, followed by the comparison with the virtual robot motion path that was created by the joint interpolation method. Consequently, the human arm was observed to be in motion while the elbow was bent. In return this contributed to the increase of the manipulability and decrease of gravity and torque being exerted on the elbow. In addition, the energy required for the motion decreased. Such phenomenon was more apparent under vertical motion than horizontal motion patterns, and in shorter paths than in longer ones. Thus, one can minimize the abrasion of joints by lowering the stress applied to the bones, muscles, and joints. From the perspectives of energy and durability, the robot arm will be able to utilize its motor most effectively by adopting the motion pattern of human arm. Conclusions: By applying the motion pattern of human arm to the robot arm motion, increase in efficiency and durability is expected, which will eventually produce robots capable of moving in an energy-efficient manner.

• Child Health Nursing Research
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• v.6 no.3
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• pp.329-343
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• 2000

This study was conducted to measure the degree of Korean Gender Egalitarianism among the students from six different high schools(132 girls, 127 boys) in Sunchon si, Chunnam province from Dec. 7th to Dec. 15th in 1999. The survey on gender egalitarianism was done in relation to the public understanding of the subject matter, parents' hug times, and parent's communication skills. Korean gender egalitari- anism scale was standardized by Korea Woman Developmental Institutes in 1999. The data was analyzed by SAS program. Results were as follows: 1) Generally, girls are more conscious of gender egalitariannism than boys(t=-13.79, p<.001). Above all, the younger the students are, the more they feel equal(F=8.01, p<.01). In sibling cases, two sisters have the highest level of gender egalitarianism while two brothers have the lowest level of gender egalitarianism(F=9.20, p<.001). Students who come from religious families are more inclined to demonstrate gender equality(t= 2.42, p<.05). However, there is no difference in relation to the parents' ages or academic background or harmony within the family. 2) There is no difference that girls and boys generally communicate with their parents. In ages, 17 years old students communicate more than 18, 19 with parents(father F=3.97 p<.05ㆍmother F=5.31, p<.01). That is, the younger students can communicate with their mothers more often than the older ones. In sibling cases, two sisters have more openly communication to parents while two brothers have(F=2.84, p<.05). Students communicate with their parents regardless of parents' academic background. But those from the family in harmony have more open chance to communicate than those who are not in hamony(father F=21.66, p<.001ㆍmother F=13.37, p<.001). They can comm -unicate with their parents better when their fathers hug them than when they didn't get hugs(father t=-4.76, p<.001ㆍ mother t= -2.34, p<.05). They can also communicate with their patents better when their mothers hug them once or more than when they didn't get hugs(father t=-3.78, p<.001ㆍmother t=-5.64, p<.001). 3) There is no difference whether the father hugs or not, but the mother's hug is very important because students whose mothers hug them once or more have significantly more gender egalitarianism than those students whose mothers didn't do(t=-3.98, p<.001). Based upon these results, it is recommended that we reconsider the role of gender in the socialization of high school students and also include gender egalitarianism in sex education. In this context, further study should be done for the improvement of students' communication within the framework of egalitarianism based upon parents' hugs(semi-language). Continued study is especially important in regards to the mother's hug and its enhancement of the students' gender egalitarianism.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.5
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• pp.301-313
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• 2021

Theoretical background for the meaning of various piezoelectric properties can be easily found in a number of textbooks and academic papers. In contrast, how they are actually measured and characterized are rarely described, though this information would be the most important especially to the researchers who just started working on the field. It follows that this report was intended to provide a practical guidance for measuring basic but essential properties of ferroelectric-based piezoelectric materials. The discussion begins with how to measurement dielectric properties such as dielectric permittivity and loss (dissipation factor), followed by piezoelectric properties such as piezoelectric constants, electromechanical coupling factor, and quality factor as well as ferroelectric features, i.e., electric field dependent polarization hysteresis. Though our discussion here is limited to the techniques that are already well-standardized, it is expected to make a seed to be developed into more challenging and creative ones.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.659-668
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• 2006

The optimization of supercritical water oxidation (SCWO) process for decomposing nitromethane was studied by means of a design of experiments. The optimum operating region for the SCWO process to minimize COD and T-N of treated water was obtained in a lab scale unit. The authors had compared the results from a SCWO pilot plant with those from a lab scale system to explore the problems of scale-up of SCWO process. The COD and T-N in treated waters were selected as key process output variables (KPOV) for optimization, and the reaction temperature (Temp) and the mole ratio of nitromethane to ammonium hydroxide (NAR) were selected as key process input variables (KPIV) through the preliminary tests. The central composite design as a statistical design of experiments was applied to the optimization, and the experimental results were analyzed by means of the response surface method. From the main effects analysis, it was declared that COD of treated water steeply decreased with increasing Temp but slightly decreased with an increase in NAR, and T-N decreased with increasing both Temp and NAR. At lower Temp as $420{\sim}430^{\circ}C$, the T-N steeply decreased with an increase in NAR, however its variation was negligible at higher Temp above $450^{\circ}C$. The regression equations for COD and T-N were obtained as quadratic models with coded Temp and NAR, and they were confirmed with coefficient of determination ($r^2$) and normality of standardized residuals. The optimum operating region was defined as Temp $450-460^{\circ}C$ and NAR 1.03-1.08 by the intersection area of COD < 2 mg/L and T-N < 40 mg/L with regression equations and considering corrosion prevention. To confirm the optimization results and investigate the scale-up problems of SCWO process, the nitromethane was decomposed in a pilot plant. The experimental results from a SCWO pilot plant were compared with regression equations of COD and T-N, respectively. The results of COD and T-N from a pilot plant could be predicted well with regression equations which were derived in a lab scale SCWO system, although the errors of pilot plant data were larger than lab ones. The predictabilities were confirmed by the parity plots and the normality analyses of standardized residuals.