• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.637-642
• /
• 2011

Rails are subjected to damage from rolling contact fatigue, which leads to defects such as cracks. Rolling contact fatigue damages on the surface of rail such as head check, squats are one of growing problems. Another form of rail surface damage, known as "Ballast imprint" has become apparent. This form of damage is associated with ballast particles becoming trapped between the wheel and the surface of rail. These defects are still one of the key reasons for rail maintenance and replacement. In this study, we have investigated whether the ballast imprint is an initiator of head check type cracks and effect of defect size using Finite element analysis. The FE analysis were used to investigate stresses and strains in subsurface of defects according to variation of defect size. Based on loading cycles obtained from FE analysis, fatigue analysis for each point was carried out.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.4
• /
• pp.339-345
• /
• 2006

An analysis methodology of Decentralized Dynamic Surface Control (DDSC) for the large-scale interconnected nonlinear systems is presented in this paper. While the centralized DSC approach proposed in [14] has a difficulty to check the quadratic stability for the large-scale systems numerically due to dramatic increases of the order of overall augmented error dynamics, DDSC is relatively easy to check the quadratic stability since lower order error dynamics of individual subsystems are used. Then, a systematic procedure for designing DDSC will be developed. Furthermore, after a quadratic function containing a reachable set is defined, it will be calculated numerically to indicate the performance of DDSC in the framework of convex optimization. Finally an illustrative example will be given for showing the advantages of DDSC compared with other decentralized nonlinear control techniques.

• Journal of Welding and Joining
• /
• v.21 no.7
• /
• pp.65-70
• /
• 2003

Thermal emissivity is generally affected by surface situation of material such as roughness. In this study, the effect of surface roughness on measuring thermal emissivity is experimented. And emissivity measurement method and equipment using hemisperical mirror is also reviewed. As the result of this research, thermal emissivity increased as long as increasing surface roughness. So, surface roughness is a essential check point when we measure the emissivity.

• English & American cultural studies
• /
• v.14 no.2
• /
• pp.49-75
• /
• 2014

This paper argues that John Leguizamo disguises ethical intention with humor in his one-person show, Freak. The argument proceeds in three stages. First, on the basis of Slavoj ${\check{Z}}i{\check{z}}ek^{\prime}s$ theory that fantasies teach us how to desire discussed in The Sublime Object of Ideology, I analyze how and why Leguizamo exaggerates and thus de-constructs the ideological fantasies about Latin Americans in Freak. Through this analysis the ridiculous exaggeration of the fantasies and their deconstruction emerges as the means to surface the trauma caused by the fantasies, internally and externally curing and reconciling the audience. Second, I apply ${\check{Z}}i{\check{z}}ek^{\prime}s$ theory of the quilting point introduced in Looking Awry: An Introduction to Jacques Lacan through Popular Culture to reveal how "blots" in Freak form "black holes" in the audience's consciousness to smash their established view of the reality, inducing them to encounter with "the real." The investigation into Leguizamo's use of humor as the quilting point illuminates how he invites the audience to look awry beyond the popular fantasy at "the real" America. Third, on the ground of Emmanuel Levinas's theory that theaters are the space of ethics, namely "ethotopos" to emphasize responsible actions discussed in "Ethics as First Philosophy," I assert that Leguizamo disguises his ethical message with humor so as for the audience to recognize their responsibility for others in America and take action towards change.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1994.10a
• /
• pp.188-192
• /
• 1994

This paper presenta new method for tool interference acoidance using rectanguar approximation in NC machining of scuptured surface. The procedure of algorithm for approximation of sculptured surface to rectangular surface is described. Using this algorithm, we can check concave, convex, and side interference region and avoid these interferenes.

• Atmosphere
• /
• v.29 no.4
• /
• pp.501-509
• /
• 2019

Asian Dust is a meteorological phenomenon that sand particles are raised from the arid and semi-arid regions-Taklamakan Desert, Gobi Desert and Inner Mongolia in China-and transported by westerlies and deposited on the surface. Asian dust results in a negative effect on human health as well as environmental, social and economic aspects. For monitoring of Asian Dust, Korea Meteorological Administration operates 29 stations using a continuous ambient particulate monitor. Kim et al. (2016) developed an automatic quality check (AQC) algorithm for objective and systematic quality check of observed PM₁₀ concentration and evaluated AQC with results of a manual quality check (MQC). The results showed the AQC algorithm could detect abnormal observations efficiently but it also presented a large number of false alarms which result from valid error check. To complement the deficiency of AQC and to develop an AQC system which can be applied in real-time, AQC has been modulated. Based on the analysis of instrument status codes, valid error check process was revised and 6 status codes were further considered as normal. Also, time continuity check and spike check were modified so that posterior data was not referred at inspection time. Two-year observed PM₁₀ concentration data and corresponding MQC results were used to evaluate the modulated AQC compared to the original AQC algorithm. The results showed a false alarm ratio decreased from 0.44 to 0.09 and the accuracy and the probability of detection were conserved well in spite of the exclusion of posterior data at inspection time.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.626-630
• /
• 1996

The most important problem in NC machining of a freeform mold surface is removal of tool interference. In this paper three methods are introduced to remove self-intersection on offsetted freeform surface for 3-axis NC. All methods are using intersectional offset curves on original offset surface. The fast method is sequential loop check using two lines which have two neighbor points of intersectional offset curves.

• Journal of the Korean Wood Science and Technology
• /
• v.39 no.2
• /
• pp.125-131
• /
• 2011

The characteristics of radio-frequency/vacuum drying Japanese larch boxed heart round logs with 150 mm and 210 mm in diameter and 2,500 mm in length, subjected to compressive loading, after the pretreatment of kerf were investigated. The results of this study were as the follows: The drying time of about 120 hours~130 hours was needed from green to about 15 percent of moisture content. The gradient of final moisture content for all specimens was very gentle in both longitudinal and transverse directions owing to dielectric heating. The surface checks seriously occurred although the occurrence extent of surface check for the kerfed specimens was slight compared with that for the control specimens because drying stress was relieved by kerf. The occurrence of surface checks for the L-specimen was more serious than that for the S-specimen.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.6
• /
• pp.613-620
• /
• 2012

Rails are subjected to damage from rolling contact fatigue, which leads to defects such as cracks. Rolling contact fatigue damages on the surface of rail such as head check, squats are one of growing problems. Another form of rail surface damage, known as "Ballast imprint" has become apparent. This form of damage is associated with ballast particles becoming trapped between the wheel and the surface of rail. These defects are still one of the key reasons for rail maintenance and replacement. In this study, we have investigated whether the ballast imprint is an initiator of head check type cracks and effect of defect size using Finite element analysis. The FE analysis were used to investigate stresses and strains in subsurface of defects according to variation of defect size. Based on loading cycles obtained from FE analysis, fatigue analysis for each point was carried out.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.26-32
• /
• 2008

Middle Route Project, the largest water conveyance system in China delivers the water of Changjiang River to North China. In order to create canal operation simulation system, mathematical models are established based on the analysis of hydraulics about steady flow, unsteady flow, and check gate. By simulating the canal operation behavior, we improved the check gate control algorithm and predicted the change process of water surface and flow profile which is very valuable to actual canal operation.