• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.4
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• pp.1738-1756
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• 2020

To improve the accuracy and realism of the virtual surgical simulation system, this paper proposes an optimized mass-spring model with shape restoration ability based on volume conservation to simulate soft tissue deformation. The proposed method constructs a soft tissue surface model that adopts a new flexion spring for resisting bending and incorporates it into the mass-spring model (MSM) to restore the original shape. Then, we employ the particle swarm optimization algorithm to achieve the optimal solution of the model parameters. Besides, the volume conservation constraint is applied to the position-based dynamics (PBD) approach to maintain the volume of the deformable object for constructing the soft tissue volumetric model base on tetrahedrons. Finally, we built a simulation system on the PHANTOM OMNI force tactile interaction device to realize the deformation simulation of the virtual liver. Experimental results show that the proposed model has a good shape restoration ability and incompressibility, which can enhance the deformation accuracy and interactive realism.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.863-868
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• 2007

본 연구는 Haptic System의 물리적 stiffness(N/mm)와 사용자의 주관적 촉감정보(단단하다, 무르다)의 상관성에 관한 것이다. tangible media와 같은 컨텐츠의 촉감을 실감나게 표현하기 위해서는 사용자가 주관적으로 느끼는 힘의 강도가 haptic system에 매핑이 되어야 한다. 따라서 사용자의 주관적인 힘의 강도와 haptic system의 물리적 stiffness간에 상관성 연구가 필요하다. 본 연구에서는 물리적 특성을 결정하고 하드웨어와 소프트웨어를 연동시켜 촉감을 모델링하는 haptic 렌더링을 통해 정량화된 외부의 자극(변화)에 대해 사람이 심리적으로 느끼고 있는 감각을 정량화하여 입력 자극과의 관계를 밝히고자 팬텀을 이용해 두 번의 실험을 실시하였다. 먼저 haptic system에서 사용자가 힘의 차이를 느낄 수 있는 stiffness의 해상도를 측정하고, 그에 따라 나뉘어진 해상도 별로 촉감에 대한 주관적인 평가를 하였다. ANOVA결과에 따르면 haptic system의 물리적 stiffness와 사용자의 주관적 촉감정보간에 유의한 상관관계가 분석되었으며 회귀분석을 실시하여 유의한 정도를 회귀 방정식으로 도출하였다. 따라서tangible media를 이용한 실감적인 촉감 컨텐츠를 재현하는 기술에 본 연구결과가 유용하게 사용되리라 기대된다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.2 s.314
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• pp.37-46
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• 2007

In this paper, we propose technologies for enhancing the immersive realization of virtual objects in AR-based product design. Generally, multimodal senses such as visual/auditory/tactile feedback are well known as a method for enhancing the immersion in case of interaction with virtual objects. By adapting tangible objects we can provide touch sensation to users. A 3D model of the same scale overlays the whole area of the tangible object so the marker area is invisible. This contributes to enhancing immersion. Also, the hand occlusion problem when the virtual objects overlay the user's hands is partially solved, providing more immersive and natural images to users. Finally, multimodal feedback also creates better immersion. In our work, both vibrotactile feedback through page motors, pneumatic tactile feedback, and sound feedback are considered. In our scenario, a game-phone model is selected, by way of proposed augmented vibrotactile feedback, hands occlusion-reduced visual effects and sound feedback are provided to users. These proposed methodologies will contribute to a better immersive realization of the conventional AR system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.208-216
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• 2003

ISO 14649 (data model for STEP-NC) is a new interface scheme or language for CAD-CAM-CNC chain under established by ISO TC184 SCI. Up to this point, the new language is mainly made for milling and turning, and other processes such as EDM will be completed in the future. Upon completion, it will be used as the international standard language for e-manufacturing paradigm by replacing the old machine-level language, so called M&G code used since 1950's. With the rich information contents included in the new language, various intelligent functions can be made by the CNC as the CNC knows what-to-make and how-to-make. In particular, On-Machine Inspection required for quality assurance in the machine level, can be done based on the information of feature­based tolerance graph. Previously, On-Machine inspection has been investigated mainly for milling operation, and only a few researches were made for turning operation without addressing the data model. In this thesis, we present a feature-based on-machine inspection process by the 4 Tasks: 1) proposing a new schema for STEP-NC data model, 2) converting the conventional tolerance scheme into that of STEP-NC, 3) modifying the tolerance graph such that the tolerance can be effectively measured by the touch probe on the machine, and 4) generating collision-free tool path for actual measurement. Task 1 is required for the incorporation of the presented method in the ISO 14649, whose current version does not much include the detailed schema for tolerance. Based on the presented schema, the tolerance represented in the conventional drafting can be changed to that of STEP-NC (Task 2). A special emphasis was given to Task 3 to make the represented tolerance accurately measurable by the touch probe on the machine even if the part setup is changed. Finally, Task 4 is converting the result of Task into the motion of touch probe. The developed schema and algorithms were illustrated by several examples including that of ISO 14649 Part 12.

• Journal of Fashion Business
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• v.6 no.5
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• pp.1-11
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• 2002

Today, great percentage of apparel fabrics comprise knit products. A few apparel items are almost exclusively made from knit products including sweaters, T-shirts, lingerie, and hosiery. In weft knits, intermeshing yarn traverses the fabric crosswise. The production rate of knitting machines is about four times higher than that of conventional looms iin proportion to the amount of fabric produced per unit time. Knit apparels fabrics are noted for freedom of body movement, easy-care, resilience, soft draping and quality. The appearance of fabrics is of prime importance along with tactile features such as smoothness, crispness, stiffness when we deal with the handling evaluation of the textiles. In practice, the quality and performance of fabrics judged by sighted evaluators, and it is perhaps logical, in attempting to establish an effective fabric objective measurement system. It is worthwhile to make objective measurement that correlate well with subjective evaluations made by sight and touch together. However, it often imposes difficulties to effectively measure and analyze the appearance or optical properties of the textile surface features. In this study, an attempt is made to provide a preliminary approach to the analysis of the gloss property, which is one of the optical properties of fabrics. The specimens range from 70/24 nylon 6 filament yarn knit fabric to 70/68 nylon 6 filament yarn knit fabric, the latter being finer. A few three-dimensional models based on Peirce's model of knit stitch have been proposed and material properties were given to calculate the properties. Goniophotometric measurements of the specimens were also carried out.

• Annals of Surgical Treatment and Research
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• v.95 no.6
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• pp.297-302
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• 2018

Purpose: Increased robotic surgery is attended by increased reports of complications, largely due to limited operative view and lack of tactile sense. These kinds of obstacles, which seldom occur in open surgery, are challenging for beginner surgeons. To enhance robotic surgery safety, we created an augmented reality (AR) model of the organs around the thyroid glands, and tested the AR model applicability in robotic thyroidectomy. Methods: We created AR images of the thyroid gland, common carotid arteries, trachea, and esophagus using preoperative CT images of a thyroid carcinoma patient. For a preliminary test, we overlaid the AR images on a 3-dimensional printed model at five different angles and evaluated its accuracy using Dice similarity coefficient. We then overlaid the AR images on the real-time operative images during robotic thyroidectomy. Results: The Dice similarity coefficients ranged from 0.984 to 0.9908, and the mean of the five different angles was 0.987. During the entire process of robotic thyroidectomy, the AR images were successfully overlaid on the real-time operative images using manual registration. Conclusion: We successfully demonstrated the use of AR on the operative field during robotic thyroidectomy. Although there are currently limitations, the use of AR in robotic surgery will become more practical as the technology advances and may contribute to the enhancement of surgical safety.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.266-274
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• 2006

본 논문은 새로운 햅틱 API 인 "K-Touch"의 개발에 관한 것이다. 그래픽 하드웨어 기반의 핵심 역감 알고리즘을 기반으로 개발된 K-Touch API 는 가상 환경을 구성하는 다양한 데이터 형식(3D polygon model, volume data, 2.5D depth image)에 대한 햅틱 상호작용을 가능하게 하고, 새로운 햅틱 알고리즘 및 장치 개발에 필요한 소프트웨어 확장성을 제공함과 동시에 사용자가 쉽고 빠르게 햅틱 응용분야를 개발할 수 있도록 설계되었다. 아울러 햅틱 감각의 중요 요소인 역감 및 촉감 상호작용을 위해 기존의 햅틱 SDK 및 API 와 달리 역/촉감을 동시에 제시할 수 있는 알고리즘이 개발되었다. 본 논문에서 제안하는 새로운 햅틱 API 의 효용성을 검증하기 위해 다양한 응용분야의 예를 구현하였다. 새로운 햅틱 API 인 K-Touch 는 사용자 및 연구자에게 보다 효율적으로 햅틱 연구를 진행 할 수 있도록 도움을 주는 툴(Tool)로써 중요한 역할을 할 것으로 기대된다.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.396-401
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• 2009

This paper describes the improvements made on hardware and software of the remote controller for realistic contents. The controller can provide vibrotactile feedback which uses both of a voice-coil actuator and a vibration motor. A vision tracking system for the 3D position of the controller is optimized with respect to the marker size and the camera parameters. We also present the improvements of motion recognition due to the effective motion segmentation and the fusion of vision and acceleration data. We apply the developed controller to realistic contents and validate its usability.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2003.05a
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• pp.94-100
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• 2003

Patients with schizophrenia have thinking disorders such as delusion or hallucination, because they have a deficit in the ability which to systematize and integrate information. Therefore, they cannot integrate or systemize visual, auditory and tactile stimuli. In this study we suggest a virtual reality system for the assessment of cognitive ability of schizophrenia patients, based on the brain multimodal integration model. The virtual reality system provides multimodal stimuli, such as visual and auditory stimuli, to the patient, and can evaluate the patient's multimodal integration and working memory integration abilities by making the patient interpret and react to multimodal stimuli, which must be remembered for a given period of time. The clinical study showed that the virtual reality program developed is comparable to those of the WCST and the SPM.

• Korean Institute of Interior Design Journal
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• v.13 no.2
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• pp.56-63
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• 2004

Harmony between men and their surroundings has been one of the most profound motives in space and object design for a long time. It is often expressed in design as the concept of 'organic'. Nowdays the term of organic is expanding its meaning in the contemporary sense of organicism. Nature, human 'beings, and digital technology are the key issues in future design paradigms. Karim Rashid is one of the most futuristic and vendible designer and his works show these issues. His designs flow organically and he uses materials that allow his forms to flow like the body, echoing life forms. it's very sensual, very tactile. In his work, a new concept of organic design is expressed in the organic unity of experience. He tries to contribute objects to our physical landscape that inspires, engages, and encourage positive experiences. Also, Technology is at constant play in his design process. With the latest three dimensional design software it is much easier to design and model sophisticated and complex shape and forms. Digital technology affects not only his design processes but also cultural views. New technologies and social shifts are changing our understanding of interior space.