• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.254-258
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• 2009

In this paper, the low frequency vibration forming system is developed for micro-patterns formation on the metal substrate. many researchers have studied about micro-forming technologies such as micro deep drawing, press forming, forging, extrusion etc. for the formation of precise micro-patterns on the surface of metal substrates, multi-step forming process must be used to improve qualifies of the deformed patterns. Since the low frequency vibration forming system could easily deform the surface of metal substrates, several steps of multi-step forming process should be removed by using the low frequency vibration forming system. In order to find optimal process conditions, we have carried out low frequency vibration forming process with varying the vibration frequency from 110Hz to 500Hz.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.256-261
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• 2008

We developed an authoring tool for designing vibrotactile patterns quickly and easily by using the drag-and-drop paradigm in mobile devices. Designed vibrotactile patterns are registered into a data pool in the XML format, improving the reusability and extensibility of vibrotactile patterns. A multi-channel timeline interface is also incorporated to provide time-synchronized pattern editing for multiple vibration patterns (for multiple vibration actuators). In addition, an internal vibration player is embedded in the authoring tool in order to evaluate the patterns on the spot. A transform function for perceptually transparent vibration rendering can also be set in the editor. Although the authoring tool was developed for mobile devices, it can be used for other applications such as haptic interaction m virtual reality.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.9
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• pp.785-796
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• 2007

This study offers a design procedure of optimum cable damper for multi-mode vibration control with nonlinear damper and also investigates the relation between mode and amplitude dependency. The proposed multi-mode damping index, which is defined as a potential energy loss ratio of cable vibration, is a main component of optimization problem of optimum nonlinear damper. In order to include the amplitude dependency of nonlinear damper, three types of multi-mode patterns such as ambient vibration, support excitation and rain-wind induced vibration are assumed. The optimum damper exponent depends on amplitude patterns. In case of ambient vibration, optimum factor is less than 0.5 and in case of support excitation or rain-wind induced vibration it is between 0.5 and 1.0.

• 전기의세계
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• v.26 no.5
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• pp.74-82
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• 1977

This study is to present a method for reductin of noise and vibration of home electric motors coupled to the mechanical load causing relatively big amplitude of vibration. The noise and vibration factors have been analysed in the divisions such as the pattern related to the armature reaction, the pattern related to the circulating current by induction and the other patterns those are affected by a dditive magnetic field and have an effect on mechanical constants. From the systematic mutual relations between the patterns and daping effects, it is possible to derive the fundamental measure for reduction of noise and vibration. Vibration measurements and analysis were carried out in accordance with the planned experimentation and thre object model was chosen randomly from the production line in a factory where home electric machines were mass-produced. Based on the above-mentioned fundamental measure, suppression effects on noise and vibration have been analysed according to the number of slots, the amount of rotor skew and the way the stator winding connection was series or parallel.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.147-156
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• 2007

This study offers a design procedure of optimum cable damper for multi-mode vibration control with nonlinear damper and also investigate the relation between mode and amplitude dependency. The proposed multi-mode damping index, which is defined as a energy loss ratio of cable potential, is a main component of optimization problem of optimum nonlinear damper. In order to include the amplitude dependency of nonlinear damper, it is assumed to exist three kinds of multi-mode patterns such as ambient vibration, support excitation and rain-win induced vibration. The optimum damper exponent depends on amplitude patterns. In case of ambient vibration, optimum factor is less than 0.5. In case of support excitation or rain-wind induced vibration is between 0.5 and 1.0. In this study, the effects of cable sag and inclination angle are included in the asymptotic design equation of damped cable structures.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.329-336
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• 1998

The characteristics of vibration and sound signals which occurs at the driving system of electric train are investigated in this study since the vibration of driving system is one of the main sources of vibration and sound in electric train. The vibration signals are changed its signal patterns during the transmission from the source to passengers due to noise or several unknown factors. To avoid the complexity of actual signals of electric train, signals from experimental apparatus of motor/gear driving system are analyzed to find the appropriate method of analysis and to characterize the signal patterns. The used methods are waterfall diagram, transfer function and modal analysis. The results shows that the vibration signals are usually originated from motor bearing and gear meshing and these signals are transmitted to bottom or bogie. Also, the sound signal is similar to the vibration of bottom or bogie, but it is not so clear to figure out the source of vibration.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.363-369
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• 2011

In this study, a direct pattern forming process on a plastic film using ultrasonic vibration energy is investigated. A tool horn containing micro-patterns is attached to an ultrasonic power supply, and is used to press a plastic film with ultrasonic vibration in order to replicate micro-patterns on the surface of the plastic film. To replicate micro-patterns with high accuracy, the tool horn should be designed to allow only the longitudinal vibration, not the transverse vibration. For this purpose, the design of a tool horn is investigated through finite element analysis, from which the resulting natural frequency of the tool horn can be adjusted in the range of the ultrasonic power supply. The analysis result is then reflected on the optimal design and fabrication of the tool horn. The validity of the developed tool horn is discussed through pattern-forming experiments using the ultrasonic vibration of the developed tool horn.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.413-418
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• 2013

As haptic devices become increasingly important in various product fields, it becomes essential to design effective vibration patterns for better tactile sensitivities. Despite this trend, standardization in the design of vibration patterns has not been well established, which causes developers to neglect the effects of haptics while programming or developing products. To provide better tactile sensitivity, the present study introduces a vibration pattern design system and proposes guidelines for designing vibration patterns. This system consists of two modules: (1) a graphical pattern design and evaluation program and (2) a vibro-tactile display device for prototyping the designed vibration patterns.

• Explosives and Blasting
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• v.28 no.1
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• pp.11-18
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• 2010

This study improved construction and cost efficiency that are disadvantages of existing low vibration crackers(low vibration cracker, plasma, etc) and introduced cases of development and practical applications of Low vibration explosives(NewFINECKER) that minimizes blast vibration. The low vibration explosives(NewFINECKER) is suitable to Type-1 among standard blasting patterns of Ministry of Land, Transport and Maritime Affairs(MLTM) and delay blasting is possible. Moreover, the low vibration explosives improve construction and work efficiency while the level of vibration is shown to be about 60~70% of normal emulsion explosives. Additionally, this study suggested standard blasting patterns, the prediction equation of blasting vibration, and construction methods.

• Genomics & Informatics
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• v.10 no.2
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• pp.128-132
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• 2012

To learn the differences between the structure-activity relationship and molecular vibration-activity relationship in the ligand-receptor interaction of the histamine receptor, 47 ligands of the histamine receptor were analyzed by structural similarity and molecular vibrational frequency patterns. The radial tree that was produced by clustering analysis of molecular vibrational frequency patterns shows its potential for the functional classification of histamine receptor ligands.