• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.50-57
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• 1997

In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstations to provide the required intelligence of the expert. This paper deals with condition monitoring for chatter, tool wear and breakage during turning operation. To develop economic sensing and identiffication methods for turning processes, sound pressure measurement and digital signal processing technique were proposed. We suppressed chatter by stability control methodology, which was studied through manipulation of spindle speeds regarding to chatter frequencies. It was shown that tool wear and fracture were identified and to be estimated by using the wear indices. The validity of the proposed system was confirmed through the large number of cutting tests.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1219-1224
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• 2006

This paper presents the friction and anti-wear characteristics of nano-oil with n mixture of a refrigerant oil and carbon nano-particles in the thrust slide-bearing of scroll compressors. Frictional loss in the thrust slide-bearing occupies a large part of total mechanical loss in scroll compressors. The characteristics of friction and anti-wear Lising nano-oil is evaluated using the thrust bearing tester for measuring friction surface temperature and the coefficient of friction at the thrust slide-bearing as a function of normal loads up to 4,000 N and orbiting speed up to 3,200 rpm. It is found that the coefficient of friction increases with decreasing orbiting speed and normal force. The friction coefficient of carbon nano-oil is 0.015, while that of pure oil is 0.023 under the conditions of refrigerant gas R-22 at the pressure of 5 bars. It is believed that carbon nano-particles can be coated on the friction surfaces and the interaction of nano-particles between surfaces can be improved the lubrication in the friction surfaces. Carbon nano-oilenhances the characteristics of the anti-wear and friction at the thrust slide-bearing of scroll compressors.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.3
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• pp.280-287
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• 2019

In the oral cavity, the teeth undergo wear and corrosion throughout their lives. Progressive and constant tooth wear is a natural phenomenon of aging, but wear and corrosion due to specific factors are pathological factors. It can cause pathological damage of the occlusal surface, aesthetic problems, dimensional loss and jaw joint disorders. This case is a 26-year-old female patient with general tooth abrasion and erosion on the entire dentition. Diagnostic wax-up was fabricated based on the information including digital facial analysis, physiological stabilization, and evaluation of anterior crown length. Through the digital analysis, the necessary guides for crown lengthening were prepared and the mastication function and esthetics were evaluated by using temporary crowns. Definitive prosthesis was fabricated with the zirconia restorations. The results were satisfactory when they were observed 3 months of follow-up.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.4
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• pp.320-329
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• 2022

Physiological wear of occlusal surface is inevitable throughout the lifetime, and considered to be normal. Pathologic wear, however, may cause fatal damage to the occlusal surface and destroy esthetics and proper anterior guidance. In such cases, rehabilitation of occlusal wear should be followed by thorough evaluation and diagnosis. In this present case, severe occlusal wear was found in the labial surfaces of mandibular anterior teeth and palatal surfaces of maxillary anterior teeth. Occlusal vertical dimension was evaluated and decided to be regained due to insufficient amount of restorative space. After determining new occlusal vertical dimension, diagnostic wax-up is usually performed to continue prosthodontic treatment. In this case with collapsed occlusion and loss of occlusal vertical dimension, conventional diagnostic wax-up was replaced with various digital devices. Diagnostic wax-up was digitally performed in the software and provisional prosthesis was fabricated with digital tools. With verification with provisional prosthesis, the entire dentition was rehabilitated with newly set occlusal vertical dimension and proper anterior guidance.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.457-458
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• 2002

The fractal dimension is the characteristics that can quantitatively define the irregularity in natural. It is useful in describing the morphology or various rubbed surface for hydraulic piston motor instead of the stylus profiling method. But fractal parameters had not constructed on the morphological characteristic or rubbed surface because of the insufficient knowledge about a conception of fractal dimension. In this study, for the purpose or applying fractal I parameters practically, we have suggested way to establish the morphological characteristic of rubbed surface with fractal parameters, and we carried out an experiment on the lubricant friction and wear by using Ball-ON-Disk type tester. Materials were the brass and the bronze which are used to slipper-pad in the hydraulic piston motor. We searched for fractal parameters or surface structure with the digital image processing, Surface fractal dimension can be determined by sum of intensity difference of surface pixel. Using the image processing and fractal parameters for rubbed surface in the friction and wear test, morphology of rubbed sur race can be effectively obtained by fractal dimensions.

• Journal of the Korean Society of Costume
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• v.59 no.2
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• pp.70-86
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• 2009

Today, digital technology is extending its influence to fashion design, which is closely related to people's lifestyle. In order for people to access information all the time, every place, people have to wear these devices all the time, every place. Intelligent wear allows people to communicate with their own body, other persons or surrounding real-time. The purposes of this study are to define 'Intelligent wear' by looking through the similar terms of intelligent wear on related fields, to analyze characteristics of intelligent wear and to provide not only theoretical data but also, practical data far product development on both functional and aesthetic sides. In this study, usefulness provided by intelligent wear were identified in the concept of instrumental & expressive function. For the aim of the study, literature and case study were considered at the same time. The conclusions are as the following. The characteristics of intelligent materials were found to be information, intelligence and protection, the characteristics of intelligent manufacture were combination and virtual reality. And The characteristics of intelligent products were multi-function, transformation, camouflage. Integration of operability function extends human ability and the area of human activity, entertainment, and communication, and provides convenience. Consequently, development of intelligent wear should promote through not only computer engineering but also, connection to other fields. Most of all, there is a need for active research in clothing design and the fashion design since intelligent wear is after all, clothing.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.82-87
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• 1997

In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstation to provide the required intelligence of the expert. This paper deals with condition monitoring for tool wear and fracture during turning operation. Developing economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique are proposed. The validity of the proposed system is confirmed through the large number of cutting tests.

• The Research Journal of the Costume Culture
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• v.17 no.1
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• pp.40-54
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• 2009

Many studies make us difficult for understanding the specific concept of NOW avant garde by misusing avant garde or by using the over wide-ranging concept. The purpose of this study is to define the concept of NOW avant garde fashion by analyzing its fashion and its paradigm characteristics, after considering modern avant garde fashion history. This study was used with bibliographic research as well as internet search of qualitative method for analyzing fashion show clothes since 2005 women's wear. The characteristics of NOW avant garde fashion are classified into plural deconstructivism, econonism that integrates the last avant garde factors with logical economics, and the aesthetic of Tech-Human. To conclude, the concept of NOW avant garde fashion is defined as the fashion expressing either the digital-hybrid images or the deconstructive images meaning elimination, unification or confinement, being pilled up one on another, bizarre connection, transposition, and distortion.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.2061-2068
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• 1993

Condition monitoring technology is of great importance for the maintenance of complex machinery in view of its early monitoring of the abnormal condition and the protection against failure. Several methods have been used for the detection of failure of journal bearings, one of the main elements of mechanical system. The methods most frequently used are vibration and temperature monitoring, but these are unable to monitor the wear conditions exactly. In this study, an ultrasonic measument method, one of the non-destructive testing methods, was introduced as the monitoring technology. Furtermore a pattem recognition method was applied to analyze the ultrasonic signal. The monitoring system using the pattern recognition method is composed of digital signal processing units and uses Hamming net algorithm for the recognition of ultrasonic waves. From the journal bearing wear test, the occurrence of adhesive wear of the white metal in rubbing contact with the shaft was exactly detected by this system, and the wear status of the journal bearing was monitored by measuring the wear thickness.

• The Journal of Advanced Prosthodontics
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• v.11 no.1
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• pp.23-31
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• 2019

PURPOSE. To investigate and compare the surface roughness (SR), weight and height of monolithic zirconia (MZ), ceramometal (CM), lithium disilicate glass ceramic (LD), composite resin (CR), and their antagonistic human teeth enamel. MATERIALS AND METHODS. 32 disc shaped specimens for the four test materials (n=8) and 32 premolars were prepared and randomly divided. SR, weight and height of the materials and the antagonist enamel were recorded before and after subjecting the specimens to 240,000 wear-cycles ($49N/0.8Hz/5^{\circ}C/50^{\circ}C$). SR, height, weight, and digital microscopic qualitative evaluation were measured. RESULTS. CM ($0.23+0.08{\mu}m$) and LD ($0.68+0.16{\mu}m$) exhibited the least and highest mean difference in the SR, respectively. ANOVA revealed significance (P=.001) between the materials for the SR. Paired T-Test showed significance (P<.05) for the pre- and post- SR for all the materials. For the antagonistic enamel, no significance (P=.987) was found between the groups. However, the pre- and post- SR values of all the enamel groups were significant (P<.05). Wear cycles had significant effect on enamel weight loss against all the materials (P<.05). CR and MZ showed the lowest and highest height loss of 0.14 mm and 0.46 mm, respectively. CONCLUSION. MZ and CM are more resistant to SR against the enamel than LD and CR. Enamel worn against test materials showed similar SR. Significant variations in SR values for the tested materials (MZ, LD, CM, and CR) against the enamel were found. Wear simulation significantly affected the enamel weight loss against all the materials, and enamel antagonist against MZ and CM showed more height loss.