• Korea-Australia Rheology Journal
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• v.13 no.2
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• pp.97-106
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• 2001

Three-dimensional flow analysis was performed by using the control volume finite-element method for design of a profile extrusion die. Because polymer melt behavior is complicated and cross-sectional shape of the profile extrusion die is changing continuously, the fluid flow within the die must be analyzed three-dimensionally. A commercially available polypropylene is used for theoretical and experimental investigations. Material properties are assumed to be constant except for the viscosity. The 5-constant modified Cross model is used for the numerical analysis. A test problem is examined in order to verify the accuracy of the numerical method. Simulations are performed for conditions of three different screw speeds and three different die temperatures. Predicted pressure distribution is compared with the experimental measurements and the results of the previous two-dimensional study. The computational results obtained by using three dimensional CVFEM agree with the experimental measurements and are more accurate than those obtained by using the two-dimensional cross-sectional method. The velocity profiles and the temperature distributions within several cross-sections of the die are given as contour plots.

• Structural Engineering and Mechanics
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• v.63 no.6
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• pp.751-760
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• 2017

In recent years, multifractal-based analysis methods have been widely applied in engineering. Among these methods, multifractal detrended cross-correlation analysis (MFDXA), a branch of fractal analysis, has been successfully applied in the fields of finance and biomedicine. For its great potential in reflecting the subtle characteristic among signals, a structural health monitoring (SHM) system based on MFDXA is proposed. In this system, damage assessment is conducted by exploiting the concept of multifractal theory to quantify the complexity of the vibration signal measured from a structure. According to the proposed algorithm, the damage condition is first distinguished by multifractal detrended fluctuation analysis. Subsequently, the relationship between the q-order, q-order detrended covariance, and length of segment is further explored. The dissimilarity between damaged and undamaged cases is visualized on contour diagrams, and the damage location can thus be detected using signals measured from different floors. Moreover, a damage index is proposed to efficiently enhance the SHM process. A seven-story benchmark structure, located at the National Center for Research on Earthquake Engineering (NCREE), was employed for an experimental verification to demonstrate the performance of the proposed SHM algorithm. According to the results, the damage condition and orientation could be correctly identified using the MFDXA algorithm and the proposed damage index. Since only the ambient vibration signal is required along with a set of initial reference measurements, the proposed SHM system can provide a lower cost, efficient, and reliable monitoring process.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.215-218
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• 2001

Finite element models are constructed using the commercial code ANSYS for two most representative types of ultrasonic transducers, cMUTs and piezoelectric transducers. Calculation result shows the origin and level of cross talk between array elements in each transducer type For reduction of the cross talk level, the effects of various structural variations are Investigated for each transducer type. The results say that proper design of the coupling isolation structures between the transducing elements can significantly reduce the cross talk in ultrasonic transducers.

• Asian Journal of Innovation and Policy
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• v.8 no.1
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• pp.73-96
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• 2019

This study suggests a new approach for identifying core robot tech-nologies based on technological cross-impact. Specifically, the approach applies data mining techniques and multi-criteria decision-making methods to the co-classification information of registered patents on the robots. First, a cross-impact matrix is constructed with the confidence values by applying association rule mining (ARM) to the co-classification information of patents. Analytic network process (ANP) is applied to the co-classification frequency matrix for deriving weights of each robot technology. Then, a technique for order performance by similarity to ideal solution (TOPSIS) is employed to the derived cross-impact matrix and weights for identifying core robot technologies from the overall cross-impact perspective. It is expected that the proposed approach could help robot technology managers to formulate strategy and policy for technology planning of robot area.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1894-1906
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• 2016

The purpose of this study is to analyze the setting and directions of cross-curricular learning topics based on research on experts' recognition of cross-curricular learning topics. The study method adopted was Delphi, and the subjects selected were curricular experts. This study has drawn following results: first, regarding the essence and problems of cross-curricular learning topics, even among the experts, there is no opinion agreed about cross-curricular learning topics' concept, essence, or characters. Second, more detailed discussion is demanded to select cross-curricular learning topics and set up a guideline about the operation. Third, it is needed to examine closely if presently suggested cross-curricular learning topics are duplicated or not and consider related subjects connected with those cross-curricular learning topics to improve education more systematically. Fourth, it is necessary to conduct more profound and systematic research on core competence that can embrace those cross-curricular learning topics. Fifth, to cope with changes in society and demands at school, it is needed to discuss how cross-curricular learning topics should be added or which learning topics should be added.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.8
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• pp.1312-1322
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• 2006

A recent accelerated globalization has changed every aspect of consumers' life on the globe, thus understanding the similarity and the difference among people in the world became the crucial element of business for many global companies. As one of the most globalized industries in Korea, fashion businesses also require urgent assistance of academics in understanding global consumers. This study aimed to analyze cross-cultural fashion marketing studies published in two respectful journals in fashion studies: Journal of Korean Society of Clothing and Textiles and Journal of the Korean Society of Costume. Four researchers independently searched the target journals to locate studies using cross-cultural approaches. A total of 45 cross-cultural studies published in two journals between 1977 and 2005 were found and analyzed. The major findings could be summarized as followed. First, the US was the most frequently studied country followed by China, Japan, Hong Kong and others. Second, popular subjects of cross cultural studies in fashion marketing were fashion marketing environment and management rather than consumer psychology. Third, about 78% of the sampled studies were using quantitative approach, and statistical methods such as factor analysis, t-test, ANOVA, and $X^2$ analysis were commonly used. Finally, problems in sampling methods, translation of scales, and equivalence of concept, measure and sample were analyzed. Suggestions for future cross-cultural studies were discussed.

• Human Ecology Research
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• v.56 no.2
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• pp.109-122
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• 2018

Cross-border online shopping is an example of non-mobile transnational consumption behavior that has become more popular over the last decade due to the development of technology and transportation. Based on the Theory of Reasoned Action(TRA), this study proposed and tested the hypothesized model that would explain the relationships among consumption beliefs, attitudes toward cross-border online shopping, subjective norms, and purchase intention. Consumption beliefs were measured by global consumption orientation, consumer orientation, and global brand beliefs. In addition, subjective norms included two types: online and offline norms. Descriptive statistics and path analysis were employed for the analysis of the dataset of 174 participants. As a result, the hypothesized model was generally supported. Consistent with the hypothesis, global consumption orientation and global brand beliefs were positively related to positive attitudes toward cross-border online shopping but negatively associated with consumer ethnocentrism. Offline subjective norms positively predicted both the attitudes and purchase intention whereas online subjective norms only predicted purchase intention. The results reflected that TRA was applicable to the intention of cross-border online shopping in a current on-line shopping context. We also discussed the practical applications and limitations of the study.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1224-1227
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• 1998

This paper presents an effect of cross magnetization to the generator characteristics in synchronous machine infinite bus system. Eigenvalues, synchronous torque and damping torque are investigated as the operating condition of the system is changed variously. The simulation results show that cross magnetization has an important effect to the generator characteristics in steady state stability analysis.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.4
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• pp.76-86
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• 2019

The cross-flow turbine is a key hydraulic power system that is widely due to low costs, high efficiency, and low maintenance. In particular, the cross-flow turbine considered as the most suitable turbine for low head situations as it is known to operate down to 5 m of water head. However, the conventional cross-flow turbine is unsuitable for ultra-low head situations with less than a 3 m water head. In this study, we propose an inverted-type cross-flow turbine to overcome the limitations of conventional cross-flow turbines under ultra-low head situations. First, we described the limitations of conventional turbines and suggested a new turbine for the ultra-low head circumstances. Second, we investigated the performance of the new turbine using CFD analysis. Results demonstrated the effects of the design parameters, such as number of blades and rotor diameter ratio, on the performance of the suggested turbine. As a result, we developed an inverted-type cross-flow turbine with up to 60% efficiency under low water head conditions.

• Journal of Mechanical Science and Technology
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• v.14 no.9
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• pp.935-946
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• 2000

Elastic-plastic stress analysis has been performed to evaluate the fatigue life of an autofrettaged pressure vessel containing cross-bores subjected to pulsating internal pressure of 200 MPa. Finite element analyses were used to calculate the residual and operating stress distributions of the pressure vessel due to the autofrettage process and pulsating internal pressure, respectively. Theoretical stress concentration factors of 3.06, 2.58, and 2.64 were obtained at the cross-bore of the pressure vessel due to internal pressure, 50%, and 100% autofrettage loadings, respectively. Local stresses and local strains determined from the elastic-plastic finite element analysis were employed to calculate the failure location and fatigue life of the pressure vessel with radial cross-bores, incorporating the low-cycle fatigue properties of the pressure vessel steel and fatigue damage parameters. Increase in the amount of overstrain by autofrettage process moved the crack initiation location from the inner radius toward a mid-wall, and extended the crack initiation life. Predicted fatigue life of the fully autofrettaged pressure vessel with cross-bores increased about 50%, compared to the unautofrettaged pressure vessel. At the autofrettage level higher than 50%, the failure location and fatigue life of the pressure vessel were not significantly influenced by the autofrettage level.