• ETRI Journal
• /
• v.24 no.2
• /
• pp.97-108
• /
• 2002

Optical Border Gateway Protocol (OBGP) is an extension to BGP for Optical Cross Connects (OXCs) to automatically setup multiple direct optical lightpaths between many different autonomous domains. With OBGP, the routing component of a network may be distributed to the edge of the network while the packet classification and forwarding is done in the core. However, it is necessary to analyze the stable convergence functions of OBGP in case of lightpath failures. In this paper, we first describe the architecture of the OBGP model and analyze the potential problems of OBGP, e.g., virtual BGP router convergence behavior in the presence of lightpath failure. We then propose an OBGP convergence model derived from an inter-AS (Autonomous System) relationship. The evaluation results show that the proposed model can be used for a stable OBGP routing policy and OBGP routing convergence under lightpath failures of the optical Internet.

• Steel and Composite Structures
• /
• v.27 no.6
• /
• pp.761-775
• /
• 2018

In the present work, the recently developed non-polynomial shear deformation theories are assessed for thermo-mechanical response characteristics of laminated composite plates. The applicability and accuracy of these theories for static, buckling and free vibration responses were ascertained in the recent past by several authors. However, the assessment of these theories for thermo-mechanical analysis of the laminated composite structures is still to be ascertained. The response characteristics are investigated in linear and non-linear thermal gradient and also in the presence and absence of mechanical transverse loads. The laminated composite plates are modelled using recently developed six shear deformation theories involving different shear strain functions. The principle of virtual work is used to develop the governing system of equations. The Navier type closed form solution is adopted to yield the exact solution of the developed equation for simply supported cross ply laminated plates. The thermo-mechanical response characteristics due to these six different theories are obtained and compared with the existing results.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.45 no.1
• /
• pp.146-158
• /
• 1996

The WKB method has been widely used in evaluating of the propagation characteristics of planar waveguides with graded-index profiles. This method, however, yields large errors when a turning point is near or at the discontinuity in the presence of the index discontinuity or index slope discontinuity. Especially, in the case of a truncated-index profile, this phenomenon appears more clearly in the low-order modes and near the cutoff regions. The MWKB method is introduced to reduce these inherent errors of the conventional WKB method. The MWKB method is based on both the linearization of the index profile from an index discontinuity and the introduction of a virtual turning point. It is noticed that the b-v curves obtained by the MWKB method agree well with those of the finite-difference method, and that the phase shift at a turning point depends on both the index profile and its propagation constant. (author). refs., figs.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.505-507
• /
• 2003

This paper describes techniques for the automated creation of geometric 3D models of the urban area us ing two 2D laser scanners and aerial images. One of the laser scanners scans an environment horizontally and the other scans vertically. Horizontal scanner is used for position estimation and vertical scanner is used for building 3D model. Aerial image is used for registration with scan data. Those models can be used for virtual reality, tele-presence, digital cinematography, and urban planning applications. Results are shown with 3D point cloud in urban area.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.6 no.3
• /
• pp.132-138
• /
• 2011

This paper presents an intelligent control approach for lateral position control of an autonomous four wheel steered snowplowing robotic vehicle. The vehicle is built for removing snow on the highway. Dynamics of the vehicle is derived and linearized for LQR control. Lateral position is controlled by the LQR method first, then the neural network control technique is introduced to improve tracking performances under the presence of load. The feasibility of using four wheel steering control is investigated by simulation studies of lateral position tracking of the Ford F-250 truck model. Performances of a LQR control method and a neural network control method under virtual snowplowing situation are compared.

• Journal of Power Electronics
• /
• v.19 no.1
• /
• pp.168-178
• /
• 2019

Discrete space vector modulation (DSVM) is an effective method to improve the steady-state performance of the finite control set predictive control for permanent magnet synchronous motor drive systems. However, it requires complex computations due to the presence of numerous virtual voltage vectors. This paper proposes an improved finite control set model-free predictive control using DSVM to reduce the computational burden. First, model-free deadbeat current control is used to generate the reference voltage vector. Then, based on the principle that the voltage vector closest to the reference voltage vector minimizes the cost function, the optimal voltage vector is obtained in an effective way which avoids evaluation of the cost function. Additionally, in order to implement double-objective control, a two-level decisional cost function is designed to sequentially reduce the stator currents tracking error and the inverter switching frequency. The effectiveness of the proposed control is validated based on experimental tests.

• Cartoon and Animation Studies
• /
• s.47
• /
• pp.1-29
• /
• 2017

360-degree virtual reality has been a technology that has been available for a long time and has been actively promoted worldwide in recent years due to development of devices such as HMD (Head Mounted Display) and development of hardware for controlling and executing images of virtual reality. The production of the 360 degree VR requires a different mode of production than the traditional video production, and the matters to be considered for the user have begun to appear. Since the virtual reality image is aimed at a platform that requires enthusiasm, presence and interaction, it is necessary to have a suitable cinematography. In VR, users can freely enjoy the world created by the director and have the advantage of being able to concentrate on his interests during playing the image. However, the director had to develope and install the device what the observer could concentrate on the narrative progression and images to be delivered. Among the various methods of transmitting images, the director can use the composition of the short. In this paper, we will study how to effectively apply the technique of directing through the composition of this shot to 360 degrees virtual reality. Currently, there are no killer contents that are still dominant in the world, including inside and outside the country. In this situation, the potential of virtual reality is recognized and various images are produced. So the way of production follows the traditional image production method, and the shot composition is the same. However, in the 360 degree virtual reality, the use of the long take or blocking technique of the conventional third person view point is used as the main production configuration, and the limit of the short configuration is felt. In addition, while the viewer can interactively view the 360-degree screen using the HMD tracking, the configuration of the shot and the connection of the shot are absolutely dependent on the director like the existing cinematography. In this study, I tried to study whether the viewer can freely change the cinematography such as the composition of the shot at a user's desired time using the feature of interaction of the VR image. To do this, 3D animation was created using a game tool called Unreal Engine to construct an interactive image. Using visual scripting of Unreal Engine called blueprint, we create a device that distinguishes the true and false condition of a condition with a trigger node, which makes a variety of shorts. Through this, various direction techniques are developed and related research is expected, and it is expected to help the development of 360 degree VR image.

• Journal of Technology Innovation
• /
• v.27 no.4
• /
• pp.111-144
• /
• 2019

As virtual assistants rapidly diffused into the market, the voice shopping market is expected to expand. The purpose of this study is to identify the factors that determine the consumers' intention to adopt voice shopping by using the unified theory of acceptance and use of technology(UTAUT). In this study, we set variables that influence the intention to adoption of voice shopping with performance expectation and effort expectations as the variables of UTAUT and playfulness expectations as an extended variable. In addition, we also include four voice secretary attributes such as response accuracy, compatibility, social presence, and safety in our research model to investigate the source of motivation of voice shopping adoption. The result of this analysis shows that variables such as performance expectation, effort expectation, and amusement expectation have a positive effect on the intention to adoption of voice shopping. With respect to the four voice shopping attributes, compatibility had a positive effect on performance expectancy, effort expectancy, and playfulness expectancy. Social presence has a positive effect on playfulness expectancy. Safety has a positive effect on effort expectancy and playfulness expectancy. On the other hand, response accuracy is not significant for performance expectancy, effort expectancy, and playfulness expectancy. This study reveals the determinants of intention to adopt the new purchasing method called voice shopping, and suggests the important factors for the innovation of commerce business.

• The Journal of Society for e-Business Studies
• /
• v.26 no.2
• /
• pp.95-122
• /
• 2021

As it recently became a non-face-to-face society because of the COVID-19 Pandemics, attempts have been made to experience heritage based on virtual reality (VR). Despite the satisfaction of VR contents, however, questions are being raised about whether the VR experience leads to visit a heritage tour or reduces to visit a heritage tour. This study examined how VR-based heritage experiences affect the visit intention of heritage sites. In addition, this study investigated how VR-based experiences differently affect the visit intention compared to web-based experiences. To this end, based on the information success model proposed by DeLone and McLean, this study examined how the perception for system quality and information quality through VR (vs. web) experience affects the intention of visiting the historical site. The results demonstrated that satisfaction was positively influenced by the convenience of system quality and the presence and usefulness of information quality and that the presence and satisfaction positively affected continuance intention. In addition, continuous intention to use positively affected the visit intention of heritage sites. Lastly, it has been shown that the usefulness of information quality in groups experiencing content through the Web (vs. VR) has a greater impact on the intent of continuous use. Based on the results of this study, we discussed ways to organize tourism content to increase the intention of visiting heritage sites.

• The Journal of the Korea Contents Association
• /
• v.18 no.8
• /
• pp.148-156
• /
• 2018

This study focuses on the play aspect of the existing digital games and VR games as part of a basic research for facilitating discussion on VR games. As a method for this research, the play aspect of digital games was classified based on the play theory by Johan Huizinga and Roger Caillois, followed by examination on the play characteristics of VR games according to the established classification. As a result, VR games share a significant portion of play characteristics with digital games. Nevertheless, in VR games the player is allowed unimpeded physical activity while having the HMD on and complete disconnection from the real world via new input/output devices. In the end, the transformation of play environment results in various sensory stimulation, and in turn influences the player's experiences in areas such as presence, immersion, emotional enjoyment and satisfaction. This study is expected to serve as an important indicator for studies on the characteristics of VR contents which is certain to develop in a wide range of directions in the future.