• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.683-685
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• 2010

Augmented reality is a technology for showing virtual objects overlapped with the real world as seen from the eyes of users. Studies are being conducted on effective communication methods using hand movements in augmented reality. Hand movements are an important means of human communication along with writing and voice. Space arrangement technology and hand tracking technology using markers to acquire virtual information in augmented reality have many limitations. This paper proposes tracking hand area for augmented object. The augmented objects change viewpoints by hand positions which improves the sense of three dimensions and immersion.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.3
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• pp.35-47
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• 1996

A surface panel method treating a boundary-value problem of the Dirichlet type is presented to design a three dimensional body with free surface corresponding to a prescribed pressure distribution. An integral equation is derived from Green's theorem, giving a relation between total potential of known strength and the unknown local flux. Upon discretization, a system of linear simultaneous equations is formed including free surface boundary condition and is solved for an assumed geometry. The pseudo local flux, present due to the incorrect positioning of the assumed geometry, plays a role f the geometry corrector, with which the new geometry is computed for the next iteration. Sample designs for submerged spheroids and Wigley hull and carried out to demonstrate the stable convergence, the effectiveness and the robustness of the method. For the calculation of the wave resistance, normal dipoles and Rankine sources are distributed on the body surface and Rankine sources on the free surface. The free surface boundary condition is linearized with respect to the oncoming flow. Four-points upwind finite difference scheme is used to compute the free surface boundary condition. A hyperboloidal panel is adopted to represent the hull surface, which can compensate the defects of the low-order panel method. The design of a 5500TEU container carrier is performed with respect to reduction of the wave resistance. To reduce the wave resistance, calculated pressure on the hull surface is modified to have the lower fluctuation, and is applied as a Dirichlet type dynamic boundary condition on the hull surface. The designed hull form is verified to have the lower wave resistance than the initial one not only by computation but by experiment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.3
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• pp.93-100
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• 2021

Since the IB (Immersed Boundary) method, which can perform coupling analysis with objects and fluids having an impermeable boundary of arbitrary shape on a fixed grid system, has been developed, the IB method in various CFD models is increasing. The representative IB methods are the directing-forcing method and the ghost cell method. The directing-forcing type method numerically satisfies the boundary condition from the fluid force calculated at the boundary surface of the structure, and the ghost-cell type method is a computational method that satisfies the boundary condition through interpolation by placing a virtual cell inside the obstacle. These IB methods have a disadvantage in that the computational algorithm is complex. In this study, the simplified immersed boundary (SIB) method enables the analysis of temporary structures on a fixed grid system and is easy to expand to three proposed dimensions. The SIB method proposed in this study is based on a one-field model for immiscible two-phase fluid that assumes that the density function of each phase moves with the center of local mass. In addition, the volume-weighted average method using the density function of the solid was applied to handle moving solid structures, and the CIP method was applied to the advection calculation to prevent numerical diffusion. To examine the analysis performance of the proposed SIB method, a numerical simulation was performed on an object falling to the free water surface. The numerical analysis result reproduced the object falling to the free water surface well.

• Cartoon and Animation Studies
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• s.22
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• pp.81-97
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• 2011

The technology of 'Virtual Reality' has placed in advanced tools for human beings' joy and anger together with sorrow and pleasure in our generation. It has recently tried in a variety ways to use as an implication for treatment in the field of Cognitive Psychology. Especially, it widely approaches to human in terms of that a sense of reality in a virtual world through the five senses should reinterpret the meaning of cognition in the real world. Based on this paradigm shift, it allows for new treatment using the technology of virtual reality. A typical example is a field of Therapy in order to overcome panic disorder. It has advantages that in particular development of flexible interaction technologies in a virtual space can lead patients to experience psychological environments rather than physical one. the interaction technology provides environments in which users' five senses can be actively stimulated, it is very useful that information from the experiences in the virtual world allows people to learn through real experiences by renewing potential energies, advantages of Virtual Reality Therapy can be customized treatment by depending on symptoms in patients with panic disorder and are capable of differentiate application for the cure at each stage. It is to treat by leading patients to get accustomed to environments and situations in real world through care process with each symptom and stage. It is helpful that based on A Human-Sensibility Ergonomics, technologies like immersive virtual reality equipment, force-relative feedback and stereophonic sound, and like stimulating the sense of smell make people to induce experiences by stimulating human's five senses. There are many advantages of immersion in virtual world in that the phenomenon such as challenge, interaction, reality, illusion, and cooperation is expanded. As an application for therapy by growing such augmented reality, virtual space and sharing of data through the Internet and also inexpensive its availability have recently expanded the base. There are other benefits of Virtual Reality Therapy offering active interaction environments for cognitive experience which can provide appropriately adjusted environments for patients who are hard to overcome the real situation because of phobia. In addition to that it is safe and economical and patients' confidentiality is assured. Moreover, due to the principles of applying real-time navigation the Virtual Reality Therapy makes modification and supplementation easier and also it can reduce cybersickness because of the supply of Lenticular allowing people to see stereoscopy without eyeglasses, which makes sense of presence clearer. On top of that due to the development of interactive technologies, it is becoming close to sense of reality similar to real world by leading users to navigate by themselves and to operate objects in a virtual space. This paper will therefore examine, although it is of limited, characteristics of application of virtual reality technology based on A Human-Sensibility Ergonomics used for treatment for a disorder. this paper will analyse a range of its application and problems and it will suggest the future possibilities.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.708-716
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• 2009

Applications which are implemented on Table Top Display are controlled by hands, so that they support an intuitive interface to users. Users feel the real sense when they interact on the virtual scene in Table Top Display. However, most of conventional augmented reality applications on Table Top Display satisfy only visual sense. In this paper, we propose an interface that supports multi-modal sense in that tactile sense is utilized for augment reality by vibrating a physical control unit when it collides to virtual objects. Users can feel the collision in addition to visual scene. The proposed system facilitates tactile augmented reality through an air hockey game. A physical control unit vibrates when it receives virtual collision data over wireless communication. Since the use of tabletop display environment is extended with a tactile sense based physical unit other than hand, it provides a more intuitive interface.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.441-447
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• 2006

See-through HMD type 3D display can provide an advantage of us seeing virtual 3D data used stereoscopic display simultaneously with real object(MR-Mixed Reality). But, when user sees stereoscopic display for a long time, not only eye fatigue phenomenon happens but also de-focus phenomenon of data happens by fixed focal point of virtual data. Dissatisfaction of focus adjustment of eye can be considered as the important reason of this phenomenon. In this paper, We proposed an application of multi-focus in see-through HMD as a solution of this problem. As a result, we confirmed that the focus adjustment coincide between the object of real world and the virtual data by multi-focus in monocular condition.

• Journal of the Korea Computer Graphics Society
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• v.23 no.3
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• pp.77-85
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• 2017

Tangible Space is a new emerging interaction space with mobile AR/VR computing and ubiquitous computing environment with IoT. Tangible Space spans from a physical environment augmented with virtual entities to immersive virtual environments mirroring the physical environment. Interacting with Tangible Space is logged just like interacting with the Web. By webizing Tangible Space, we can gain persistence as a by-product so that human life experience in the physical environment can be logged and shared just like the information being created and shared in the current Web. The result is a powerful future direction of the web from a World Wide Web of Information to World Wide Web of Life experiences.

• Journal of the Korea Computer Graphics Society
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• v.23 no.3
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• pp.87-94
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• 2017

Due to improvements in the capabilities of commercial game engines, there are increasing instances of applying game engines to scientific visualization applications. This study describes a case of creating a virtual reality application that visualizes medical volume data based on the Unity3D game engine. When using a game engine, there is an advantage that various functions required for an application are basically provided, such as depth sorting of translucent objects or virtual reality hardware support. On the other hand, there is a restriction that the structure of the application program should be modified to suit the characteristics of the game engine. This paper describes a method for visualizing medical volume data using the structure of a game engine. As a result, we were able to create a virtual reality scene that consisted of surface data and medical volume data fragments together. And we confirmed the possibility of game engine as a future medical simulation production tool.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.525-530
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• 2016

In this paper, we proposed an image shaking index to evaluate the remote controllability of vision based unmanned vehicles. To analyze the usefulness of the proposed image-shaking index, we perform subjective tests using a virtual unmanned vehicle driving simulator. The developed driving simulator consists of a real-time multibody dynamic software of the unmanned vehicle, a motion simulator, and a driver console. We perform dynamic simulations to obtain the motion of the unmanned vehicle running on the various road surfaces such as ISO roughness level A~E roads. The motion of the vehicle body is reflected in the motion simulator. Then, to enable remote control operation, we offer to operators the image data that was measured using the camera sensor on the simulator. We verify the usefulness of the proposed image-shaking index compared with subjective index provided by operators.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.451-456
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• 2009

In this paper, a virtual force is generated and fed back to the operator to make the teleoperation more reliable, which reflects the relationship between a slave robot and an uncertain remote environment as a form of an impedance. In general, for the teleoperation, the teleoperated mobile robot takes pictures of the remote environment and sends the visual information back to the operator over the Internet. Because of the limitations of communication bandwidth and narrow view-angles of camera, it is not possible to watch certain regions, for examples, the shadow and curved areas. To overcome this problem, a virtual force is generated according to both the distance between the obstacle and the robot and the approaching velocity of the obstacle w.r.t the collision vector based on the ultrasonic sensor data. This virtual force is transferred back to the master (two degrees of freedom joystick) over the Internet to enable a human operator to estimate the position of obstacle at the remote site. By holding this master, in spite of limited visual information, the operator can feel the spatial sense against the remote environment. It is demonstrated by experiments that this collision vector based haptic reflection improves the performance of teleoperated mobile robot significantly.