• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.606-608
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• 1998

가상환경기술이 여러 분야에서 보편화되고 활용되기 시작하면서 컴퓨터 프로그래밍기술이 없어도 가상환경을 손쉽게 꾸밀 수 있는 저작기술이 필요하게 되었다. 본 논문에서는 가상환경 저작용 시각 언어인 Virtual Environment Specification Language(VESL)를 사용하여 컴퓨터 프로그램 코딩을 하지 않아도 가상환경을 저작할 수 있는 기술을 구현하였다. 우리가 개발한 시각언어 편집기는 VESL을 기반으로 하여 3차원 가상환경을 구축하고 가상환경 내에 정의된 객체들의 물리적 속성을 정의하고 객체들간의 관계 및 유지를 명시함으로써 보다 현실감 있는 동적인 가상 환경을 손쉽게 저작할 수 있도록 하였다.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.19-23
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• 2008

The development of computer graphics techniques came after development of various entertainment industry such as movies, game and so on, and techniques that make diverse objects in virtual space and control the action of objects are growing rapidly. Especially objects(characters) play an important role in encouraging virtual space at computer animation field. If lots of objects are animated in virtual space, undesired matters of fixed topography or collision between objects etc occur. In order to solve this problem, we need control techniques in detail. This paper presents and implements collision evasion with submarine topography in a virtual aquarium and control technique about collision evasion with other objects.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.697-699
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• 2001

가상환경에서의 실시간 상호작용을 지원하기 위해 가상세계의 데이터를 서버에서 클라이언트로 복제 해놓는 방법이 쓰여지고 있다. 효과적인 복제를 위해서는 두 가지 기법 - 우선 순위기반의 객체 전송과 캐싱 및 프리패칭 기법이 쓰이고 있다. 기존의 캐시와 프리패칭 기법들은 사용자와 객체간의 지역적 관계를 이용하고 있지만, 이는 어떤 종류의 객체가 사용자에게 더 중요한 지를 결정할 수 없는 단점이 있다. 본 연구에서는 지역적 관계 뿐 아니라 개별 사용자의 객체에 대한 관심도로부터 발생하는 객체에 대한 우선 순위를 이용하여 사용자 기반의 캐싱과 프리패칭을 사용하는 분산 가상환경 하에서의 확장성 있는 데이터 관리 기법을 제안한다. 또한 이 기법에서는 사용자의 행동 모드를 구분함으로써 더욱 높은 캐시 적중 비율을 얻을 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.95-106
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• 1996

The most fundamental difference between general three dimensional computer graphics technology and virtual reality technology lies in the degree of realism as we feel, and thus the virtual reality method heavily relies on such tolls as data gloves, 3D auditory system to enhance human perception and recognition. Although these tolls are valid for such purpose, more essential ingredient. This paper provides further realism by modeling active interactions between the objects inside scenes. For this purpose, this paper proposes and implements a field model where the virtual reality space is treated as a physical field defined on the characteristic radius of stimulus and sense corresponding to the individual object. In the field model, the rule of cause and effect as an essential feature of the realism can be interpreted simply as an energy exchange between objects and consequently, variation on the radius information together with behavioral logic alone can build the virtual environment where each object can react to other objects actively and controllably.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.957-960
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• 2007

The construction information used in the design and construction phases are being gradually changed by 3D objects based on virtual reality (VR). This study developed an algorithm and computerized system to visualize layer object simulation that can be used in the pre-design phase. Layer object simulation enables designer to review expecting problems, which can reappear in real construction site, by building construction structures in a VR system. This function can be used as an important tool of virtual construction system.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.3
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• pp.51-58
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• 2010

Since Augmented Reality (AR) enables users to experience computer-generated content embedded in real environments, AR agents can be visualized among physical objects in the environments where the users exist, and directly interact with them in real-time. We model perceptual attention for autonomous agents in AR environments where virtual and physical objects coexist. Since such AR agents must adaptively perceive and attend to surrounded objects relevant to their goals, our model allows the agents to determine currently visible objects from the description of what virtual and physical objects are configured in the camera's viewing area. A degree of attention is assigned to each perceived object based on its relevance to achieve agents' goals. The agents can focus on a reduced set of perceived objects with respect to the estimated degree of attention. To demonstrate the effectiveness of our approach, we implemented an animated character that was overlaid over a miniature version of campus and that attended to buildings relevant to their goals. Experiments showed that our model could reduce the character's perceptual loads even when surroundings change.

• Journal of Korea Multimedia Society
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• v.9 no.4
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• pp.421-433
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• 2006

This paper proposes a method to insert virtual objects into a real video stream based on feature tracking and camera pose estimation from a set of single-camera video frames. To insert or modify 3D shapes to target video frames, the transformation from the 3D objects to the projection of the objects onto the video frames should be revealed. It is shown that, without a camera calibration process, the 3D reconstruction is possible using multiple images from a single camera under the fixed internal camera parameters. The proposed approach is based on the simplification of the camera matrix of intrinsic parameters and the use of projective geometry. The method is particularly useful for augmented reality applications to insert or modify models to a real video stream. The proposed method is based on a linear parameter estimation approach for the auto-calibration step and it enhances the stability and reduces the execution time. Several experimental results are presented on real-world video streams, demonstrating the usefulness of our method for the augmented reality applications.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.563-565
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• 1995

기존의 가상현실(Virtual Reality) 시스템들은 가상세계 (Virtual World)에 관한 데이타를 대부분 파일의 형태로 관리하고 있다. 가상현실에 대한 연구가 진전되어 공유가상세계(Shared Virtual World)를 기반으로 하는 대규모 응용분야가 나타나면서, 데이타의 효율적 관리와 공유를 위한 상위 레벨의 데이타 관리층이 필요하게 되었다. 본 논문에서는 가상세계 데이타의 관리를 위한 객체지향 DBMS(Database Management System)[1]의 사용을 제안한다. 그리고 데이터베이스에 저장된 지속객체 (Persistent Object)[2]를 공유하는 가상현실 응용시 스템의 구조를 연구한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.479-484
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• 2000

웹 기반 3차원 가상환경에서 내부 객체들간의 다양한 상호작용 기능은 가상환경이 제시하는 현실세계와의 유사성 및 참여자의 몰입감 정도를 판단하는 기준으로서 현재 좀 더 많은 연구가 필요한 분야이다. 특히 사용자를 대신하는 아바타의 다양한 행위표현과 관련하여 얼마나 이를 실세계의 개념에 가깝고 자연스럽게 지원하는지의 여부는 가상환경이 제공하는 사실감에 절대적인 영향을 데치게 된다. 본 논문에서는 아바타를 포함한 가상환경 내의 다양한 객체들을 그 특징에 따라 분류하고 이들간의 상호작용 및 행위의 유형물 정의한다. 또한 본 논문의 개념에 기반 한 가상환경시스템을 실제 구축하여 제안하는 상호작용모델에 대한 타당성을 검증한다.

• Journal of Internet Computing and Services
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• v.15 no.1
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• pp.171-178
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• 2014

This paper presents dynamic modelling of a virtual object in augmented reality environments when external forces are applied to the object in real-time fashion. In order to simulate a natural behavior of the object we employ the theory of Newtonian physics to construct motion equation of the object according to the varying external forces applied to the AR object. In dynamic modelling process, the physical interaction is taken placed between the augmented object and the physical object such as a haptic input device and the external forces are transferred to the object. The intrinsic properties of the augmented object are either rigid or elastically deformable (non-rigid) model. In case of the rigid object, the dynamic motion of the object is simulated when the augmented object is collided with by the haptic stick by considering linear momentum or angular momentum. In the case of the non-rigid object, the physics-based simulation approach is adopted since the elastically deformable models respond in a natural way to the external or internal forces and constraints. Depending on the characteristics of force caused by a user through a haptic interface and model's intrinsic properties, the virtual elastic object in AR is deformed naturally. In the simulation, we exploit standard mass-spring damper differential equation so called Newton's second law of motion to model deformable objects. From the experiments, we can successfully visualize the behavior of a virtual objects in AR based on the theorem of physics when the haptic device interact with the rigid or non-rigid virtual object.