• Journal of Power Electronics
• /
• v.6 no.1
• /
• pp.52-66
• /
• 2006

This paper proposes a wind energy conversion system connected to a grid using a self-excited induction generator (SEIG) based on the maximum power point tracking (MPPT) control scheme. The induction generator (IG) is controlled by the MPPT below the base speed and the maximum energy can be captured from the wind turbine. Therefore, the stator currents of the IG are optimally controlled using the indirect field orientation control (IFOC) according to the generator speed in order to maximize the generated power from the wind turbine. The SEIG feeds a (CRPWM) converter which regulates the DC-link voltage at a constant value where the speed of the IG is varied. Based on the IG d-q axes dynamic model in the synchronous reference frame at field orientation, high-performance synchronous current controllers with satisfactory performance are designed and analyzed. Utilizing these current controllers and IFOC, a fast dynamic response and low current harmonic distortion are attained. The regulated DC-link voltage feeds a grid connected CRPWM inverter. By using the virtual flux orientation control and the synchronous frame current regulators for the grid connected CRPWM inverter, a fast current response, low harmonic distortion and unity power factor are achieved. The complete system has been simulated with different wind velocities. The simulation results are presented to illustrate the effectiveness of the proposed MPPT control scheme for a wind energy system. In the simulation results, the d-q axes current controllers and DC-link voltage controller give prominent dynamic response in command tracking and load regulation characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.4C
• /
• pp.277-282
• /
• 2012

In this paper, we present a real-time eye contact system for realistic telepresence using a Kinect depth camera. In order to generate the eye contact image, we capture a pair of color and depth video. Then, the foreground single user is separated from the background. Since the raw depth data includes several types of noises, we perform a joint bilateral filtering method. We apply the discontinuity-adaptive depth filter to the filtered depth map to reduce the disocclusion area. From the color image and the preprocessed depth map, we construct a user mesh model at the virtual viewpoint. The entire system is implemented through GPU-based parallel programming for real-time processing. Experimental results have shown that the proposed eye contact system is efficient in realizing eye contact, providing the realistic telepresence.

• Composites Research
• /
• v.29 no.1
• /
• pp.16-23
• /
• 2016

In this paper, numerical results of sectional analysis, stress recovery and energy release rate were compared with the results of VABS, 3-D FEM through the blade analysis library. The result of stress recovery analysis for one-dimensional model including the stiffness matrix is compared with stress results of three-dimensional FEM. We discuss the configuration of the blade analysis library and compare verifications of numerical analysis results of VABS. Blade analysis library through dimensional reduction and stress recovery is intended to be utilized in conjunction with pre- and post-processing of the analysis program of the composite blade, high-altitude uav's wing, wind blades and tilt rotor blade.

• Structural Engineering and Mechanics
• /
• v.66 no.3
• /
• pp.353-368
• /
• 2018

In this work, a high order hyperbolic shear deformation theory with four variables is presented to study the vibratory behavior of functionally graduated plates. The field of displacement of the theory used in this work is introduced indeterminate integral variables. In addition, the effect of porosity is studied. It is assumed that the material characteristics of the porous FGM plate, varies continuously in the direction of thickness as a function of the power law model in terms of volume fractions of constituents taken into account the homogeneous distribution of porosity. The equations of motion are obtained using the principle of virtual work. An analytical solution of the Navier type for free vibration analysis is obtained for a FGM plate for simply supported boundary conditions. A comparison of the results obtained with those of the literature is made to verify the accuracy and efficiency of the present theory. It can be concluded from his results that the current theory is not only accurate but also simple for the presentation of the response of free vibration and the effect of porosity on the latter.

• Journal of Digital Convergence
• /
• v.11 no.1
• /
• pp.423-430
• /
• 2013

The development of information technology introduced digital contents and Social Network Services(SNS), and allowed the virtual transaction and communication between users called "the experience knowledge" advanced from "the objective knowledge." This paper will analyze interactive storytelling system creating different types of stories on narrative genre about family history, personal history and so on. Through analysis on narrative interviews, direct observations, documentations and visual records, contents about CEO story, corporate story, family story and especially family history will be categorized into sampleDB and informationDB. Accumulated contents will allow the user to increase the value and usage of the contents through interactive storytelling system by restructuring the contents on family history. This research has developed writing tool data model using different digital contents such as texts, images and pictures to encourage open communications between first generations and third generations in Korea. Furthermore, researched about connected system on interactive storytelling creation device using various genre of family story that has been data based.

• Journal of the East Asian Society of Dietary Life
• /
• v.22 no.2
• /
• pp.315-321
• /
• 2012

In this study, the product attributes that give customers the estimated benefits and products that can predict the customer's choice conjoint analysis techniques to identify the restaurant affinity markets a new dining concept was to develop. Questionnaire for this study of 400 non-response is negative and insincere characters, except for the final analysis, the questionnaire Part 309 was the target. Conjoint model used in this study Pearson's R is 0.928 ($p$<0.000), Kendall's tau is 0.750 ($p$<0.000) with an orthogonal plan was well suited for profiling attributes are extracted 16. Part of the relative importance of the value of the property to determine the result of analyzing the properties that are most important at the level of the respondents of the induct (38.46%), and followed by price (30.52%), Atmosphere (18.28%), and Exclusive space (12.73%) was followed. Portion of the property value for each analysis among industry preference for the Italian food was highest, a nature-friendly interior atmosphere had the highest affinity Average per price at 10,000 won~30,000 won or less than the amount of affinity was higher location of the restaurant alone, showed that space preferred. Through simulation in a virtual seafood restaurant nature-friendly image, average price per person ranging from 10,000 to 30,000won at an exclusive restaurant was most preferred.

• International Journal of Advanced Culture Technology
• /
• v.8 no.2
• /
• pp.116-128
• /
• 2020

In this study, we introduce a multi-modal mixed reality (MR) application for advertising the main touristic landmarks on Jeju Island, and evaluate its effectiveness based on the Technology Acceptance Model (TAM) with a focus on the user's involvement in Korean culture (K-Culture). Specifically, we deployed several stimuli to enable users to retrieve information, visualize a variety of heritage content such as text, images, videos, virtual artifacts, and immerse in a VR environment to experience the heritage locations. The results of the online survey with 436 participants showed that for consumers with low K-Culture involvement, Perceived Usefulness and Perceived Ease-of-Use did not affect their Intention to Visit the island. Still, it had a significant impact on their Intention to Use the application. On the other hand, for the group with high K-Culture involvement, Perceived Usefulness had no effect on the Intention to Use and Intention to Visit. However, Perceived Ease-of-Use had a significant impact on their Intention to Use the application and Intention to Visit Jeju Island. Therefore, when user involvement in K-Culture is high, convenience of use has played a significant role in sensory media usage and the intention to visit, regardless of the usefulness of the mixed reality content. In contrast, users with low K-Culture involvement primarily focused on the functional aspects of the application. These findings open the path for follow-up studies on K-Culture involvement and immersive media tourism marketing, which will benefit digital tourism marketing and Korea's tourism industry.

• Journal of Digital Contents Society
• /
• v.5 no.1
• /
• pp.22-27
• /
• 2004

To handle the high level radioactive materials such a spent fuel, the master-slave manipulaters (MSM) are wide1y used as a remote handling device in nuclear facilities such as the hot cell with sealed and shielded space. In this paper, the Digital Mockup which simulates the remote operation of the Advanced Conditioning Process(ACP) is developed. Also, the workspace and the motion of the slave manipulator, as well as, the remote operation task should be analyzed. The process equipment of ACP and Maintenance/Handling Device are drawn in 3D CAD model using IGRIP. Modeling device of manipulator is assigned with various mobile attributes such as a relative position, kinematics constraints, and a range of mobility. The 3D graphic simulator using the extermal input device of spare ball displays the movement of manipulator. To connect the exterral input device to the graphic simulator, the interface program of external input device with 6 DOF is deigned using the Low Level Tele-operation Interface(LLTI). The experimental result show that the developed simulation system gives much-improved human interface characteristics and shows satisfactory reponse characteristics in terms of synchronization speed. This should be useful for the development of work`s education system in the environment.

• Journal of Korea Society of Industrial Information Systems
• /
• v.8 no.4
• /
• pp.55-63
• /
• 2003

The game & multimedia industry is a high-valued industry comparing to any industry. Also, it has been shown the possibility as considerably bright future industry due to a development of the Internet, an explosive growth of on-line game market, and a union with virtual reality technology Since an on-line game having a clear profit model is expanding to PC and other platform, it brings to us a large change throughout the whole game industry. In order to develop a game, we need a number of elements. A game character among them delivers to a user the overall characteristics of a game as a visual representation and makes us access to a game directly and sensuously. A game character of on-line game is considerable in an operation in the volume of initial sales from a viewpoint of marketing. In addition, it affects to secure users and be immersed in a game. In this paper, we propose a production skill of an efficient 3D game character for 3D on-line game.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.2
• /
• pp.222-228
• /
• 2012

Haptics and virtual reality are rapidly growing technologies in medical fields. Physicians and nurses can benefit from medical simulation via training and acquire surgical and clinical techniques. In this paper, the research on needle insertion force of biological tissue for haptic based intravenous injection simulator was carried out. We built the setup for needle insertion (intravenous injection) experiments and performed the experiments on live pigs. The force responses against needle insertion were measured using the experimental setup. In addition, the modeling of needle insertion force was carried out with the experimental results and numerical models via nonlinear least-squares method. The results presented in this paper indicate that the developed models can be applied not only to estimate the force feedback during intravenous injection procedure but also to improve the overall training quality of the medical simulator.