• 한국CDE학회논문집
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• 제4권1호
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• pp.12-18
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• 1999

A deformable non-Uniform Rational B-Spline (NURBS) based volume is programed for the force reflecting exoskeleton haptic device. In this work, a direct free form deformation (DFFD) technique is applied for the realistic manipulation. In order to implement the real-time deformation, a nodal mapping technique is used to connect points on the virtual object with the NURBS volume. This geometric modeling technique is ideally incorporated with the force reflecting haptic device as a virtual interface. The results in this work introduce details for the complete set-up for the realistic virtual clay modeling task with force feedback. The force reflecting exoskeleton haptic manipulator, coupled with a supporting PUMA 560 manipulator and the virtual clay model are integrated with the graphics display, and results show that the force feedback from the realistic physically based virtual environment can greately enhance the sense of immersion.

• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.116-119
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• 2019

User interface/experience and realistic game manipulation play an important role in virtual reality first-person-shooting game. This paper presents an intuitive hands-free interface of gaming interaction scheme for FPS based on user's gesture recognition and VR controller. We focus on conventional interface of VR FPS interaction, and design the player interaction wearing head mounted display with two motion controllers; leap motion to handle low-level physics interaction and VIVE tracker to control movement of the player joints in the VR world. The FPS prototype system shows that the design interface helps to enjoy playing immersive FPS and gives players a new gaming experience.

• 한국HCI학회논문지
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• 제2권2호
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• pp.53-59
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• 2007

3D/가상환경 애플리케이션을 위한 3D 인터랙션에 관한 연구는 이동(navigation), 선택(selection), 조작 (manipulation), 시스템 제어(system control)와 같은 기본적인 4가지 형태의 상호작용으로 정의하고 광범위하게 연구되어 왔으며, 일반적으로 현실세계나 가상환경에서 작은 물체라도 상호작용하기에 적합한 기술로 여겨져 왔다. 그러나 이러한 비직관적인 상호작용 방법은 최근 산업계에서 필요시 되고 있는 가상 훈련이나 가상 디자인/사용성 평가 시스템과 같이 사용자가 도구나 장치를 사용하여 간접적으로 물체를 조작해야 하는 비직관적인 상호작용 방법이 아닌, 자신의 손으로 직접 물체를 만지거나 조작할 수 있는 직관적인 상호작용 방법이 필요한 고품질, 고정밀 애플리케이션을 지원하기에는 적합하지 않은 방법이었다. 따라서 본 연구에서는 직관적이며 자연스러운 상호작용을 지원하기 위한 방법으로 고정밀 핸드 조작과 사실적 역.촉감을 제공하는 장갑형 핸드 인터페이스 장치 및 햅틱 장갑 장치와 6자유도 햅틱 장치로 구성된 핸드 햅틱 인터페이스를 제시하고자 한다.

• 한국콘텐츠학회논문지
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• 제10권8호
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• pp.461-471
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• 2010

최근, 현실세계와 가상세계를 결합하여 디지털 컨텐츠 형태로 보여주는 증강 현실 기술이 등장하고 있다. 증강현실 기술의 효과를 극대화하기 위해서, 사용자가 현실세계의 사물을 조작하는 것과 유사한 방법으로 디지털 콘텐츠와 상호작용하는 것을 가능하게 해 주는 실감형 인터페이스가 적용된다. 특히, 교육 분야에서는 이러한 기술들이 학습자의 흥미와 몰입도를 높이고, 학습 효과를 극대화할 수 있는 새로운 학습 콘텐츠의 제작을 가능하게 할 것으로 기대되고 있다. 본 논문에서는 멀티 터치스크린과 실감형 인터페이스를 적용한 과학 실험 학습 시스템을 제안한다. 이 시스템은 종래의 실험대 위에서 이루어지는 실험도구의 조작을 대체하기 위하여 대형 멀티 터치스크린을 장착한 실험 테이블과 간단한 사용자의 제스쳐를 인식할 수 있는 실감형 학습 디바이스를 사용한다. 실제 과학 실험에서는 높은 비용이나 긴 시간, 또는 위험 물질들이 요구되기도 하는데, 본 시스템은 이러한 요인들을 극복하면서 학습자들에게 다양한 실험을 현실감 있게 제공할 수 있다.

• 접착 및 계면
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• 제5권2호
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• pp.22-36
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• 2004

Several in-situ testing methods of adhesively bonded joints under static short-time tensile loading are critically analyzed in terms of experimental procedure and data evaluation. Due to its rather homogeneous stress state across the glue line, the tensile-shear test with thick single-lap specimens, according to ISO 11003-2, has become the most important test process for the determination of realistic materials parameters. This basic method, which was improved in both, the experimental part by stepped adherends and easily attachable extensometers and the evaluation procedure by numeric substrate deformation correction and test simulation based on the finite element method (FEM), is therefore demonstrated by application to several kinds of adhesives and metallic adherends. Multi-axial load decreases the strength of a joint. This effect, which is illustrated by an experimental comparison, impedes the derivation of realistic mechanical characteristics from measured force-displacement curves. It is shown by numeric modeling that tensile-shear tests with thin plate substrates according to ISO 4587, which are widely used for quick industrial quality assurance, reveal an inhomogeneous stress state, especially because of relatively large adherend deformation. Complete experimental determination of the elastic properties of bonded joints requires independent measurement of at least two characteristics. As the thick-adherend tensile-shear test directly yields the shear modulus, the tensile butt-joint test according to ISO 6922 represents the most obvious complement of the test programme. Thus, validity of analytical correction formulae proposed in literature for the derivation of realistic materials characteristics is verified by numeric simulation. Moreover, the influence of the substrate deformation is examined and a FEM correction method introduced.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.283-289
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• 2009

In level set method, material properties are made to change smoothly across an interface of two materials with different properties by introducing an interpolation or smoothing scheme. So far, the weighted arithmetic mean (WAM) method has been exclusively adopted in level set method, without complete assessment for its validity. We showed here that the weighted harmonic mean (WHM) method for rate constants of various rate processes, including viscosity, thermal conductivity, electrical conductivity, and permittivity, gives much more accurate results than the WAM method. The selection of interpolation scheme is particularly important in multi-phase electrohydrodynamic problems in which driving force for fluid flow is electrical force exerted on the phase interface. Our analysis also showed that WHM method for both electrical conductivity and permittivity gives not only more accurate, but also more physically realistic distribution of electrical force at the interface. Our arguments are confirmed by numerical simulations of drop deformation under DC electric field.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.745-750
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• 2000

Steel plate bonding technique is most widely used in strengthening of existing concrete structures, but it has inherently a problem of the premature failure such as interface separation and rip off. So far, many studies have been arid out in the manner of laboratory tests for the reinforced concrete beams to find out he mechanism of the premature failure. However, in order to verify the characteristics of the premature failure, more reasonable local investigations are needed rather than such relatively global experimental works. In this study, therefore, the double lap test which simulate the pure shear loadings and the half beam tests which consider combined flexure-shear force have been done. There are, however, difficulties in getting the normal stress caused to premature failure, so that finite element analysis was performed, too. In numerical study, material nonlinearity was considered, and the interface element was applied to model the interface between steel plate and adhesive. From the results of experimental and numerical studies, a realistic failure criterion on the separation of steel plates has been derived.

• Educational Technology International
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• 제18권1호
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• pp.49-71
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• 2017

The purpose of the study was to identify key design features of virtual reality with head-mounted displays (HMD) and touchless interface for the hearing-impaired and hard-of-hearing learners. The virtual reality based training program was aimed to help hearing-impaired learners in machine operating learning, which requires spatial understanding to operate. We developed an immersive virtual learning environment prototype with an HMD (Oculus Rift) and a touchless natural user interface (Leap Motion) to identify the key design features required to enhance virtual reality for the hearing-impaired and hard-of-hearing learners. Two usability tests of the prototype were conducted, which revealed that several features in the system need revision and that the technology presents an enormous potential to help hearing-impaired learners by providing realistic and immersive learning experiences. After the usability tests of hearing-impaired students' exploring the 3D virtual space, interviews were conducted, which also established that further revision of the system is needed, which would take into account the learners' physical as well as cognitive characteristics.

• Geomechanics and Engineering
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• 제36권2호
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• pp.145-156
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• 2024

The mechanical properties of the concrete-frozen soil interface play a significant role in the stability and service performance of construction projects in cold regions. Current research mainly focuses on the precast concrete-frozen soil interface, with limited consideration for the more realistic cast-in-place concrete-frozen soil interface. The two construction methods result in completely different contact surface morphologies and exhibit significant differences in mechanical properties. Therefore, this study selects silty clay as the research object and conducts direct shear tests on the concrete-frozen soil interface under conditions of initial water content ranging from 12% to 24%, normal stress from 50 kPa to 300 kPa, and freezing temperature of -3℃. The results indicate that (1) both interface shear stress-displacement curves can be divided into three stages: rapid growth of shear stress, softening of shear stress after peak, and residual stability; (2) the peak strength of both interfaces increases initially and then decreases with an increase in water content, while residual strength is relatively less affected by water content; (3) peak strength and residual strength are linearly positively correlated with normal stress, and the strength of ice bonding is less affected by normal stress; (4) the mechanical properties of the cast-in-place concrete-frozen soil interface are significantly better than those of the precast concrete-frozen soil interface. However, when the water content is high, the former's mechanical performance deteriorates much more than the latter, leading to severe strength loss. Therefore, in practical engineering, cast-in-place concrete construction is preferred in cases of higher negative temperatures and lower water content, while precast concrete construction is considered in cases of lower negative temperatures and higher water content. This study provides reference for the construction of frozen soil-structure interface in cold regions and basic data support for improving the stability and service performance of cold region engineering.

• 센서학회지
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• 제26권5호
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• pp.297-300
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• 2017

Realistic media comprised of metadata of the five senses to provide enhanced experiences by stimulating our memory and sensations have had an increasingly pervading effect in our daily lives. Many researchers and companies are in the process of developing their own authoring systems running on different platforms to serve realistic media, resulting in compatibility issues among the systems. To tackle these issues, the International Organization for Standardization have standardized the interface, data format, protocol, API, etc. required to provide the realistic media. In particular, the ISO/IEC 23005 standard, which is called MPEG-V in SC29/WG 11, has defined XML schemas for olfaction interaction based on electronic nose (E-Nose), and scent display. In this paper, the MPEG-V standard for olfaction interaction is reviewed, and a data flow diagram that can be used for olfactory interaction based on the MPEG-V standard was designed. In addition, the necessary schemas related to the E-Nose sensor for olfactory interaction was provided.