• Journal of Korea Multimedia Society
• /
• v.12 no.1
• /
• pp.130-138
• /
• 2009

As time spent in front of the computer screens increases, an increasing number of people are using natural landscapes or virtual aquariums as their desktop and screen saver that can provide them with mental comfort. A virtual aquarium is constructed by an animation work that creates a variety of fish that freely move in a random virtual underwater environment to analyze their movement. This paper suggests a method that constructs an immersive virtual aquarium, using fluid animation method that expresses changes of shape of fluid in real time and the Smart Fish technology which is capable of an interaction according to the diverse characteristics of virtual fish. The suggested method can be used in a virtual aquarium, aquarium screen saver, virtual fish-raising game, etc., which express diverse undersea environment.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.125-129
• /
• 1996

This paper presents the haptic rendering algorithm which gives the feel information to the operator by manipulating a virtual tool with a haptic device in the simulated environment. The movement of a virtual tool grasped by the operator, which is modeled as a square is displayed in the graphic screen of a computer and the virtual environment is modeled as deformable thin film. When the tool contacts with the virtual environment, the operator is forced to feel the contact and the feature of the deformed virtual environment through the torque control of th haptic device. Contact situations are modeled as close as to the reality considering friction, elasticity and multiple contacts. Several experiments are conducted and the effectiveness of the proposed algorithm is confirmed.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.2
• /
• pp.137-144
• /
• 2010

In general, spinal fusion surgery takes pressure off the pain induced nerves, by restoring the alignment of the spine. Therefore spinal fixation system is used to maintain the alignment of spine. In this study, a biomechanical study was performed comparing the SROM(Spinal Range Of Motion) of three types of system such as Rigid, Dynesys, and Fused system to analyze the behavior of spinal fixation system inserted in vertebra. Dynesys system, a flexible posterior stabilization system that provides an alternative to fusion, is designed to preserve inter-segmental kinematics and alleviate loading at the facet joints. In this study, SROM of inter-vertebra with spinal fixation system installed in the virtual vertebra from L4 to S1 is estimated. To compare with spinal fixation system, a simulation was performed by BRG. LifeMOD 2005.5.0 was used to create the human virtual model of spinal fixation system. Through this, each SROM of flexion, extension, lateral bending, and axial rotation of human virtual model was measured. The result demonstrates that the movement of Dynesys system was similar to normal condition through allowing the movement of lumbar.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.713-716
• /
• 2000

In this study, we present a mobile robot for ultrasonic scanning of weldment. magnetic Caterpillar mechanism is selected in order to travel on the inclined surface and vertical wall. A motion control board and motor driver are developed to control four DC-servo motors. A virtual device driver is also developed for the purpose of communicating between the control board and a host PC with Dual 'port ram. To provide the mobile robot with stable and accurate movement, PID control algorithm is applied to the mobile robot control. And a vision system for detecting the weld-line are developed with laser slit beam as a light source. In the experiments, movement of the mobile robot is tested inclined on a surface and a vertical wall.

• Journal of Fashion Business
• /
• v.15 no.3
• /
• pp.84-96
• /
• 2011

With the advancements in the computer graphics sectors, the visual quality of the virtual clothing implemented by using the 3-dimensional digital clothing software system has been much improved during the past decade. Most of the cloth simulation procedures are complicated due to the multitude of parameters involved in the simulation in order to achieve the appearance of the actual textile fabrics or the movement of the actual clothing as close as possible. Bending properties affect the tactile and visual qualities of the textile fabrics along with the shear and tensile properties. In this study, dynamic bending properties, focused on the movement of the textile fabrics including damping ratio and amplitude, were measured by using a dynamic bending test system.

• PNF and Movement
• /
• v.17 no.3
• /
• pp.369-378
• /
• 2019

Purpose: This study investigated the effects of virtual reality-based task training (VRBTT) using a smart glove on upper extremity function and activity of daily living in stroke patients. Methods: Twenty-nine patients with chronic stroke disease were randomly allocated to two groups: the VRBTT group (n=14) and the control group (n=15). All patients received 30 minutes of standard occupational therapy, 5 times a week, for 8 weeks. The VRBTT group performed an additional 30 minutes of virtual reality-based rehabilitation training, 5 times a week, for 8 weeks. Results: Both groups showed significant improvements in upper extremity function, yielding an increase in FMA and K-WMFT (p<0.05). There was a more significant increase in the VRBTT group before and after interventions (p<0.05). There was no significant difference in MAS for the control group (p>0.05); however, there was a significant increase for the VRBTT group (p<0.05). In the activities of daily living, there was a significant difference in the values for K-MBI (p<0.05). In addition, both groups showed a significant increase for K-MBI and K-RNLI (p<0.05). Conclusion: This study showed that VRBTT using smart gloves can have a more positive effect on upper extremity function and activities of daily living in stroke patients than conventional intervention methods. A variety of virtual reality-based contents and glove-shaped wearable devices will help stroke patients in rehabilitation clinics recover and return to society.

• Korean Journal of Computational Design and Engineering
• /
• v.18 no.4
• /
• pp.290-298
• /
• 2013

A walking navigation system (usually known as a locomotion interface) is an interactive platform which gives simulated walking sensation to users using sensed bipedal motion signals. This enables us to perform navigation tasks using only bipedal movement. Especially, it is useful for the certain VR task which emphasizes on physical human movement, or accompanies understanding of the size and complexity of building structures. In this work, we described system components of VR walking system and investigated several types of walking platform by literature survey. We adopted a MS Kinect depth sensor for the motion recognition and a treadmill which includes directional turning mechanism for the walking platform. Through the integration of these components with a VR navigation scenario, we developed a simple VR walking navigation system. Finally several technical issues were found during development process, and further research directions were suggested for the system improvement.

• The korean journal of orthodontics
• /
• v.45 no.6
• /
• pp.275-281
• /
• 2015

Objective: To assess the accuracy of anterior tooth movement using clear aligners in integrated three-dimensional digital models. Methods: Cone-beam computed tomography was performed before and after treatment with clear aligners in 32 patients. Plaster casts were laser-scanned for virtual setup and aligner fabrication. Differences in predicted and achieved root and crown positions of anterior teeth were compared on superimposed maxillofacial digital images and virtual models and analyzed by Student's t-test. Results: The mean discrepancies in maxillary and mandibular crown positions were $0.376{\pm}0.041mm$ and $0.398{\pm}0.037mm$, respectively. Maxillary and mandibular root positions differed by $2.062{\pm}0.128mm$ and $1.941{\pm}0.154mm$, respectively. Conclusions: Crowns but not roots of anterior teeth can be moved to designated positions using clear aligners, because these appliances cause tooth movement by tilting motion.

• Cartoon and Animation Studies
• /
• s.33
• /
• pp.383-402
• /
• 2013

In this study, we apply the facial Facial Action Coding System for coding the muscular system anatomical approach facial expressions to be displayed in response to a change in sensitivity. To verify by applying the virtual character the Duchenne smile to the original. I extracted the Duchenne smile by inducing experiment of emotion (man 2, woman 2) and the movie theater department students trained for the experiment. Based on the expression that has been extracted, I collect the data of the facial muscles. Calculates the frequency of expression of the face and other parts of the body muscles around the mouth and lips, to be applied to the virtual character of the data. Orbicularis muscle to contract end of lips due to shrinkage of the Zygomatic Major is a upward movement, cheek goes up, the movement of the muscles, facial expressions appear the outer eyelid under the eye goes up with a look of smile. Muscle movement of large muscle and surrounding Zygomatic Major is observed together (AU9) muscles around the nose and (AU25, AU26, AU27) muscles around the mouth associated with openness. Duchen smile occurred in the form of Orbicularis Oculi and Zygomatic Major moves at the same time. Based on this, by separating the orbicularis muscle that is displayed in the form of laughter and sympathy to emotional feelings and viable large muscle by the will of the person, by applying to the character of the virtual, and expression of human I try to examine expression of the virtual character's ability to distinguish.

• Journal of Drive and Control
• /
• v.12 no.2
• /
• pp.27-33
• /
• 2015

Excavators are versatile earthmoving equipment that are used in civil engineering, hydraulic engineering, grading and landscaping, pipeline construction and mining. Effective operator training is essential to ensure safe and efficient operating of the machine. The virtual reality excavator based on simulation using conventional large size monitors is limited by the inability to provide a realistic real world training experience. We proposed a flexible observation method with a head tracking system to improve user feeling and sensation when operating a virtual reality excavator. First, an excavation simulator is designed by combining an excavator SimMechanics model and the virtual world. Second, a head mounted display (HMD) device is presented to replace the cumbersome large screens. Moreover, an Inertial Measurement Unit (IMU) sensor is mounted to the HMD for tracking the movement of the operator's head. These signals consequently change the virtual viewpoint of the virtual reality excavator. Simulation results were used to analyze the performance of the proposed system.