• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1555-1561
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• 2011

The dynamic behavior of a bridge under moving loads has been investigated over many years. Especially, with the introduction of High Speed Railway, numerous theoretical studies on the interaction problem between bridges and trains are carried out. In the present study, advanced bridge/train interaction analyses are performed and compared with field tests of a simply-supported 40m long PSC box girder bridge of Kyung-Bu High Speed Railway. Vertical displacements and vertical accelerations of a bridge with increasing speeds are analyzed. In addition, wheel load reduction rates and accelerations of a car-body of the train are investigated for a study of appropriateness of traffic safety criteria of bridge design specification.

• Geomechanics and Engineering
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• v.5 no.2
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• pp.165-185
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• 2013

In the present study, the numerical and experimental investigations were performed on the backfill- exterior wall-fluid interaction systems in case of empty and full tanks. For this, firstly, the non-linear three dimensional (3D) finite element models were developed considering both backfill-wall and fluid-wall interactions, and modal analyses for these systems were carried out in order to acquire modal frequencies and mode shapes by means of ANSYS finite element structural analysis program. Secondly, a series of field tests were fulfilled to define their modal characteristics and to compare the results from proposed approximation in the selected structures. Finally, comparing the theoretical predictions from the finite element models to results from experimental measurements, a close agreement was found between theory and experiment. Thus, it can be easily stated that experimental verifications provide strong support for the finite element models and the proposed procedures themselves are the meritorious approximations to the real problem, and this makes the models appealing for use in further investigations.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.516-521
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• 2014

This paper describes the development of a new piezoelectric unimorph cantilever structure intended to improve electrical output power, compared to a conventional cantilever. The proposed structure employs a cylindrical bar attached to one side of a steel plate, which is a significant factor in forced vibration mode. The feasibility of the proposed methodology was assessed experimentally and theoretically. The influence of three different types of bar material (i.e., stainless steel, silicon rubber, and urethane), and bar position, on the output voltage were examined and compared with those without the bar. The optimal position and material for the bar were identified through experimental and theoretical analyses. It appears that the electrical output power of the proposed cantilever is about 40% higher than that of a conventional unimorph cantilever.

• Tribology and Lubricants
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• v.29 no.5
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• pp.286-290
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• 2013

When a threaded fastener is tightened, the torque-tension relationship is highly sensitive to two friction components: thread friction and head friction. In this study, we carried out friction experiments and analyses to determine the optimum clamping torque setting for bolt joints. First, we measured the coefficients of thread friction and head friction under the same running conditions of the bolt clamping process for lubricated and non-lubricated bolts. We also measured axial tension through bolt clamping tests using lubricated and non-lubricated bolts attached to a strain gauge. Finally, we compared the experiment and theoretical results.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.452-459
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• 2004

The geometrical structures of various isomers of hexafluoro-1,3-butadiene (HFBD), tetrafluoro-1,3-butadiene (TFBD), and difluoro-1,3-butadiene (DFBD) have been studied theoretically. Natural steric and natural resonance theory (NRT) analyses indicate that the lower energy of skew s-cis conformer of hexafluoro-1,3-butadiene than that of the s-trans conformer is originated from the strong steric repulsions between fluorine atoms particularly in the s-trans conformer. The resonance structures generated by NRT also show that the lone electron pairs of fluorine atoms effectively extend the conjugation, and the large differences in energy among the structural isomers of tetrafluoro-1,3-butadiene and difluoro-1,3-butadiene are in part attributed to the differences in the delocalization energies, in addition to the steric repulsion between fluorine atoms. Other interatomic interactions, such as hydrogen bonding, also play important roles in determination of the structures of isomers of tetrafluoro-1,3-butadiene and difluoro-1,3-butadiene.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.2
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• pp.67-76
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• 2013

Under an imperfect channel estimation, a Device-to-Device (D2D) communication framework based on MIMO relay technology is presented. The model consists of a D2D pair equipped with M antennas and a relay equipped with N antennas as well as a cellular user equipped with M antennas. The outage probability under different relaying protocols (i.e. AF and DF protocol) with and without considering a direct link was derived. The actual and theoretical outage probability of the five links under different antenna numbers was emulated. The number of user antennas and channel estimation error was analyzed carefully to determine their impact on the outage probability of a system. The simulation verified the theory analyses and the results showed that MIMO relaying improves the D2D communication system performance.

• Culinary science and hospitality research
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• v.22 no.6
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• pp.151-159
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• 2016

With the targeted coffee consumers in Kwangju city, South Korea, this paper investigates a few determinants such as taste, aroma, mouth-feel, and satisfaction to influence coffee price, based upon self-evaluations by those who enjoy specialty coffee. Using both simple regression and standard multiple regression analyses, it turned out that tastes, smell, mouth-feel, and satisfaction of specialty coffee had effects on coffee price. This study implies that when coffee consumers decide coffee price, they consider multiple factors to influence their overall satisfaction in multiple aspects than a single facet like taste, aroma, and mouth-feel. Practical and theoretical discussion and implications are suggested for the following studies.

• Culinary science and hospitality research
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• v.23 no.6
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• pp.89-98
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• 2017

This research focused on recognizing and empirically testing a relationship between brand personality congruence and brand extension, which can lead to effective marketing strategies for the hotel industry. The objective of this research was to identify how customer's brand personality congruence affect brand extension and to then address what the most appropriate brand extension types for hotel brands are. This study offered a better approach to assess the broader impact of extension strategy for the marketer managers. The methodology for achieving these objectives were described in the following sections: developing measurements based on extensive reviews of literature and analyzing data utilized a exploratory factor analysis and a series of simple linear regression analyses. The result of this study showed customer's brand personality congruence had a great impact on the customer's positive attitude toward core brand. However, customer's attitude toward core brand had no impact on the updated attitude. The findings provided some theoretical and managerial implications for hotel operators.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.301-312
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• 2003

This paper considers the stresses and pore pressures induced in soft ground due to tunnelling and it presents and discusses the approach methods for estimating the stability of the tunnel and its heading during drained and undrained condition. In practical, the undrained analyses of the face stability of shield tunnelling in soft soil, are carried out based on the field data measured during tunnelling and the results are also evaluated.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.280-285
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• 2001

This paper presents a modelling of thermal discharge performance for a static ice-on-coil ice-storage tank. Through the present study, discharging characteristics were examined with the existing results of theoretical and numerical heat transfer analyses. Also, an experiment was conducted to obtain a real set of discharge performance. The thermal effectiveness, the ratio of the actual heat transfer rate to the maximum possible heat transfer rate, decreased when the stored energy decreased during discharging period. And the effectiveness increased as the coolant flow rate through the storage increased, of which increasing rate decreased abruptly near the maximum and the minimum stored energy. An empirical correlation was obtained from the experimental and the numerical analysis data.