• The Journal of the Acoustical Society of Korea
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• v.25 no.1E
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• pp.25-31
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• 2006

Two twin microphones may produce particular patterns of binaural directivity by time delays between the twin microphones. The boundary element method (BEM) was used for the simulation of the sound pressure field around the KEMAR head model in order to quantify the acoustic head effect. The sound pressure onto the microphone was calculated by the BEM to an incident sound pressure. Then a planar directivity pattern was formed by four sound pressure signals from four microphones. The optimal binaural directivity pattern may be achieved by adjusting time delays at each frequency while maintaining the forward beam pattern is relatively bigger than the backward beam pattern. The simulation results were verified by the experimental measurement.

• The Journal of the Acoustical Society of Korea
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• v.24 no.3E
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• pp.115-122
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• 2005

Two twin microphones may produce particular patterns of binaural directivity by time delays between twin microphones. The boundary element method (BEM) was used for the simulation of the sound pressure field around the head model in order to quantify the acoustic head effect. The sound pressure onto the microphone was calculated by the BEM to an incident sound pressure. Then a planar directivity pattern was formed by four sound pressure signals from four microphones. The optimal binaural directivity pattern may be achieved by adjusting time delays at each frequency while maintaining the forward beam pattern is relatively bigger than the backward beam pattern.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.58-67
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• 2020

In this paper, the maintenance training manual of EV vehicle was produced by utilizing digital twin technology and various sensors such as IR-based light house tracking and head tracker. In addition, through digital twin technology and VR to provide high immersiveness to users, sensory content creation technology was secured through animation and effect realization suitable for EV vehicle maintenance situation. EV vehicle maintenance training manual is 3D engine programming and real-time creation of 3D objects and minimization of screen obstacles and selection of specific menus in virtual space in the form of training simulation. In addition, automatic output from the Head Mount Display (HUD), EV vehicle maintenance and inspection, etc., user can easily operate content was produced. This technology development can enhance immersion to users through implementation of detailed scenarios for maintenance / inspection of EV vehicles" and 3D parts display by procedure, realization of animations and effects for maintenance situations. Through this study, familiarity with improving the quality of education and safety accidents and correct maintenance process and the experienced person was very helpful in learning how to use equipment naturally and how to maintain EV vehicles.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.1055-1056
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• 2010

• Journal of Welding and Joining
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• v.19 no.6
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• pp.622-629
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• 2001

The aim of this experiment is to establish the method that obtains symmetrically two nuggets in microresistance series spot welding. The sheets of austenite stainless steel STS304 applied to various electronic parts were experimented by the inverter welding power source of polarity controllable type and by the twin head for left and right electrode force to be controlled separately. The experimental results were obtained as follows : 1) When series spot welding was carried out by DC 1 pulse as welding current with same electrode force at left and right, the asymmetry of nuggets was resulted from the larger nugget of the (-) pole because of the Peltier effect. The dynamic resistance of weld spot at left and right was appeared differently according to the growth of nuggets. 2) When AC 1 cycle by welding power source of polarity controllable type was applied, the nuggets were almost symmetrically formed. 3) In a twin head, if the electrode force of (-) pole was larger than that of (+) pole, the diameters of two nuggets became to same. It was confirmed that the dynamic resistance of (-) pole was decreased to the same level as it of (+) pole. 4) Although the forces of left and right electrode were same, and only DC 1 pulse was applied, symmetric nuggets were obtained if the conductivity of (+) pole was lower than it of (-) pole.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1138-1145
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• 2022

While pursuing digitalization and paperless projects, the construction industry needs to settle on how to make the most of digitized data and information. On-site workers, who currently rely on paper documents to check and review design and construction plans, will need alternative ways to efficiently access the information without using any paper. Augmented Reality is a potential solution where the information customized to a user is aligned with the physical world. This paper proposes the Augmented Reality framework to deliver the information on on-site resources (e.g., workers and equipment) using head-mounted devices. The proposed framework was developed by interoperating Augmented Reality-supported devices and a digital twin platform in which all information related to ongoing tasks is accumulated in real-time. On-site resources appearing in the user's field of view are automatically detected by an object detection algorithm and then assigned to the corresponding information by matching the data in the digital twin platform. Preliminary experiments show the feasibility of the proposed framework. Worker detection results can be visualized on HoloLens 2 in near real-time, and the matching process obtained the accuracy greater than 88%.

• Proceedings of the KWS Conference
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• 2001.05a
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• pp.305-307
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• 2001

• Journal of ILASS-Korea
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• v.3 no.4
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• pp.50-57
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• 1998

The utilization of resonance should be considered to get the maximum effect of ultrasonic to atomize liquid. The ultrasonic generator, transducer, horn, and all attached parts are used to produce the resonance, and specially the characteristics of liquids such as liquid load, property, and etc., for the liquid atomization affinity are considered. In this study, the variable device of liquid load was made and distilled water and city water selected as experimental liquids were sprayed by a twin-fluid spray method and their diameters, distributions, and spray quantum of spray droplets were measured by the light scattering system. And all data were observed, compared and considered relatively. In results, a lot of phenomena of liquid atomization affinity by ultrasonic appeared in accordance with liquid loads, namely head h.

• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.228-234
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• 1996

It is very important to understand the domain structures of ferroelectric BaTiO3 in the poling process. Especially because {111} twinning is frequently observed in most BaTiO3 ceramics it is required to know the relations between the ferroelectric domains and the structural twin. In this study the domain structures of a {111} twinned crystal sample were observed under a polarizing microscope. and the relation between the {111} twin and the domain configurations could be classified into two types of 'V'-shape and linear shape penetrating perpendicular to the twin boundary. Domain formation obeys the symmetry of the {111} twining when a new domain structure is developed by heat treatment and surface deformation due to domain formation is also occured symmetrically between the both sides of the{111} twin boundary. This symmetrical behavior of the domains could be interpreted with the "head-to-tall" orientation of the domains across the {111} twin boundary.

• Language and Information
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• v.8 no.2
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• pp.113-130
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• 2004

In a prevailing view of meaning and reference (cf. Frege 1892), words pick out entities in the physical world by virtue of meaning. Linguists and philosophers have argued whether the meaning of a word is inside or out-side language users' mind; but, in general, they have taken it for granted that words refer to entities in the physical world. Hilary Putnam (1975), based on his famous twin-earth thought experiment, argued that the meaning of a word could not be inside language users' head. In this paper, I point out that Putnam's argument makes sense only if words refer to entities in the physical world. That is, Putnam did not provide any argument against mentalistic semantics, since he erroneously assumed that meaning, but not reference, was inside our mind in mentalistic semantics. Mentalistic semanticist, however, assume that words pick out their references inside our head (instead of a possible outside world). A number of arguments for the mentalistic position come from psychology: studies on emotion and visual perception provide numerous cases where words cannot pick out entities from the physical world, but inside our head. The mentalistic theory has desirable consequences for the philosophy of language in that some classical puzzles of language (e.g. Russell's (1919) well-known puzzle of excluded middle) are explained well in the proposed theory.