• Journal of Institute of Convergence Technology
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• v.2 no.2
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• pp.35-39
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• 2012

This paper presents the effect of data-hold methods on stability of haptic system with a virtual wall. When a human operator interacts with virtual wall, the lager the stiffness of the virtual wall is, the more realistic the operator feels that the virtual wall is. However, if the stiffness of the virtual wall becomes extremely large, the system may be unstable. When a virtual wall is designed, it is necessary to analyze the maximum available stiffness to guarantee a stable haptic interaction. The simulation model in this paper is developed based on the haptic device model, sampler, a virtual wall model, and data hold methods to compute the maximum stiffness for stability. The effectiveness of the simulation is evaluated through comparing the results of previous studies with the results of this simulation. In addition, the effects of two data hold methods, that is, zero-order hold (ZOH) and first-order hold (FOH) on the stability are analyzed and the values of the maximum available stiffness are compared through the simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.11
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• pp.877-882
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• 2016

Disaster robots have accepted tele-operation in order to share the intelligence of human operators and robot systems. Virtual wall is one of the tele-operation technology to support recognition of human operator. If the virtual wall can block the robot from dangers, the operator will feel comfortable and can concentrate on fundamental missions. In this paper, we proposes and compares three methods for virtual wall visualization in tele-operation using 3D reconstruction. First is a virtual wall visualized only with edges. A wall filled with transparent color is the second method. Finally, third method is a texture-mapped virtual wall. In the experiments, we discuss their merits and demerits in view of robot tele-operation.

• Journal of Institute of Convergence Technology
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• v.4 no.2
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• pp.17-21
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• 2014

This paper presents the effects of the time delay on the stability of the haptic system that includes a virtual wall and a first-order-hold method. The model of a haptic system includes a haptic device model with a mass and a damper, a virtual wall model, a first-order-hold model and a time delay model. In this paper, the time delay is considered as the computational time delay that is assumed to be as much as the sampling time. As the time delay increases, the maximal available stiffness of a virtual wall model is reduced reversely. The relation among the time delay and the maximum available stiffness, the mass and the damper of the haptic device are analyzed using the MATLAB simulation.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.64-70
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• 2022

In recent years, with the continuous innovation and upgrading of engine software, the real-time rendering technology in film and television has been continuously improved, and the virtual production technology has also developed rapidly. This paper introduces the green screen often used in traditional film production and a virtual production technology based on light-emitting-diode background wall that was proposed and implemented last year. We analyzed the two production methods of virtual production and compared their characteristics. Based on these results, we can better understand the differences and respective advantages of the two production methods. And we also can according to the production budget, production cycle and the creative and technical capabilities of the team make better choices during the production process. We believe virtual production technology will be production in the future to provide a more solid technical guarantee for the development of the film industry, and this work will pave the way for further research on virtual production technology.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.118-123
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• 2023

With the continuous development of emerging technologies represented by VR technology, many game developers are declaring that they are constantly trying to break the "fourth wall" and break the boundaries between virtual and reality to create game immersion for players. new game. But for many gamers, a strong sense of immersion is not the focus of their pursuit. The sense of control and safe exploration during the game is also the game experience that many gamers are pursuing. Moreover, there is ambiguity in the definition of the concept of breaking the fourth wall in the field of academic theory. The purpose of breaking the fourth wall was to separate the real world from the virtual world, to remind the audience that the actors and the audience are in two different worlds, and to trigger the audience's thinking about drama and deeper philosophy. But in the current game, it has become a blurring of the boundary between virtual and reality, pulling players into the virtual world, and focusing on the immersive experience. In this paper, we will first sort out the concept of "breaking the fourth wall", and then conduct a comparative analysis of horizontal scroll games and VR games, and conclude that the "fourth wall" has an impact on players Great conclusion.

• Journal of Institute of Convergence Technology
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• v.5 no.2
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• pp.37-42
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• 2015

This paper presents the effects of the computational time-varying delay on the stability of the haptic system that includes a virtual wall and a first-order-hold method. The model of a haptic system includes a haptic device model with a mass and a damper, a virtual wall model, a first-order-hold model and a computational time-varying delay model. In this paper, the maximum of the computational time-varying delay is assumed to be as much as the sampling time. Using the simulation, it is analyzed how the sample-hold methods and the computational time-varying delay affect the maximum available stiffness. As the maximum of computational time-varying delay increases, the maximal available stiffness of a virtual wall model is reduced.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.301-302
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• 2002

Virtual cyclones have been the subject of aerosol separation studies since they were first developed by Torczynski and Rader (1996). In the virtual cyclone (originally referred to as the anticyclone), the main particle-laden flow follows a wall that curves away from the original flow direction rather than curving into the original direction, as in a cyclone. Although a wall forms the inner boundary of the main flow, its outer boundary is formed by an adjacent flow, often a confined recirculating flow, into which particles are transferred by centrifugal action. (omitted)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5338-5343
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• 2013

In a haptic system, a virtual wall is modeled as a virtual spring. The larger the stiffness of the virtual spring is, the more improved the reality of the virtual wall is, but the more unstable the haptic system becomes. This paper shows how to increase the stiffness of the virtual spring while the stability of the haptic system is guaranteed and shows the effects of a mass (Md) and a damper (Bd) of a haptic device on the stability when first-order hold method is applied and a virtual wall is modeled as a virtual spring (Kw). The simulation results show the boundary of the virtual spring is proportional to the square root of the mass (Md) and the damper (Bd) while maintaining the stability. The relation among the virtual spring (Kw), the mass (Md) and the damper (Bd) of the haptic device, and sampling time (T) is inferred as $K_w{\leq}{1.611M_d}^{0.50}{B_d}^{0.50}T^{-1.51}$, by using the simulation results. The maximum available stiffness of the virtual spring in first-order hold method is larger than in zero-order hold method. So the reality of the virtual wall can be improved.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.75-76
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• 2010

• Journal of Institute of Convergence Technology
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• v.3 no.2
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• pp.23-29
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• 2013

When a human operator interacts with a virtual wall that is modeled as a virtual spring model, the lager the stiffness of the virtual spring is, the more realistic the operator feels that the virtual wall is. In the previous studies, it is shown that the maximum available stiffness of a virtual spring to guarantee the stability can be increased when the first-order-hold method is applied, however the effects of a human impedance on the stability are not considered. This paper presents the effects of a human impedance on stability of haptic system with a virtual spring and a first-order-hold (FOH) method. The human impedance model is modeled as a linear second-order system model. The relations between the maximum available stiffness of a virtual spring and the human impedance such as a mass, a damping and a stiffness are analyzed through the MATLAB simulation. It is shown that the maximum available stiffness is proportional to the square root of the human mass or damping respectively.