• Journal of the Korean Society for Precision Engineering
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• v.18 no.5
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• pp.65-73
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• 2001

In this paper, a mobile system using multi-wheel steering and driving mechanism is proposed to maximize maneuverability of the wheeled mobile system. Among various possible configurations, the two-wheel steering and driving systems, which is minimal in structural requirement, is proposed to reduce the complexity in actual design and difficulties in control. The system possesses three or four degrees of freedom depending on the orientations of two wheels, one or two for driving and two for steering, which implies that the system's mobility is always less than three DOF. The proposed system, nonetheless, can exactly emulate characteristics of the omnidirectional motion as long as the planned path is smooth i.e., the curvature changes continuously while velocity is not zero. Efficient kinematic and dynamic control algorithms are proposed for position and orientation control of the proposed wheeled mobile system.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.13.1-13.12
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• 2016

Background: Mandibular motion tracking system (ManMoS) has been developed for orthognathic surgery. This article aimed to introduce the ManMoS and to examine the accuracy of this system. Methods: Skeletal and dental models are reconstructed in a virtual space from the DICOM data of three-dimensional computed tomography (3D-CT) recording and the STL data of 3D scanning, respectively. The ManMoS uniquely integrates the virtual dento-skeletal model with the real motion of the dental cast mounted on the simulator, using the reference splint. Positional change of the dental cast is tracked by using the 3D motion tracking equipment and reflects on the jaw position of the virtual model in real time, generating the mixed-reality surgical simulation. ManMoS was applied for two clinical cases having a facial asymmetry. In order to assess the accuracy of the ManMoS, the positional change of the lower dental arch was compared between the virtual and real models. Results: With the measurement data of the real lower dental cast as a reference, measurement error for the whole simulation system was less than 0.32 mm. In ManMoS, the skeletal and dental asymmetries were adequately diagnosed in three dimensions. Jaw repositioning was simulated with priority given to the skeletal correction rather than the occlusal correction. In two cases, facial asymmetry was successfully improved while a normal occlusal relationship was reconstructed. Positional change measured in the virtual model did not differ significantly from that in the real model. Conclusions: It was suggested that the accuracy of the ManMoS was good enough for a clinical use. This surgical simulation system appears to meet clinical demands well and is an important facilitator of communication between orthodontists and surgeons.

• Journal of Digital Contents Society
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• v.9 no.3
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• pp.389-398
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• 2008

There has been some research into a speech system for communications between those who are hearing impaired and those who hear normally, but the system has been pursued in inefficient teaching ways in which existing teachers teach each individual due to social indifference and a lack of marketability. In order to overcome such a weakness, there appeared to be a need to develop contents utilizing 3D animation and digital technology. For the investigation of a standard face and a standard spherical shape for the preparation of a character, the study collected sufficient data concerning students in the third-sixth grades in elementary schools in Seoul and Gyeonggi, Korea, and drew up standards for a face and a spherical shape of such students. This data is not merely the basic data of content development for the hearing impaired, but it can also offer a standard measurement and a standard type realistically applicable to them. As a system for understanding conversations by applying 3D character animation and educating self-expression, the character speech animation system supports effective learning for language education for hearing impaired children who need language education within their families and in special education institutions with the combination of 3D technology and motion capture.

• Clinics in Shoulder and Elbow
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• v.26 no.2
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• pp.126-130
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• 2023

Background: Arm swing plays a role in gait by accommodating forward movement through trunk balance. This study evaluates the biomechanical characteristics of arm swing during gait. Methods: The study performed computational musculoskeletal modeling based on motion tracking in 15 participants without musculoskeletal or gait disorder. A three-dimensional (3D) motion tracking system using three Azure Kinect (Microsoft) modules was used to obtain information in the 3D location of shoulder and elbow joints. Computational modeling using AnyBody Modeling System was performed to calculate the joint moment and range of motion (ROM) during arm swing. Results: Mean ROM of the dominant elbow was 29.7°±10.2° and 14.2°±3.2° in flexion-extension and pronation-supination, respectively. Mean joint moment of the dominant elbow was 56.4±12.7 Nm, 25.6±5.2 Nm, and 19.8±4.6 Nm in flexion-extension, rotation, and abduction-adduction, respectively. Conclusions: The elbow bears the load created by gravity and muscle contracture in dynamic arm swing movement.

• Journal of Biomedical Engineering Research
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• v.31 no.2
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• pp.141-150
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• 2010

The purpose of this study was to analyze the golf swing motion for a soft golf clubs and regular golf club. Soft golf is a newly developed recreational sports for all ages, including the elderly and the beginners of golf. To quantify the effect of using soft golf club, which much lighter club than regular clubs, a motion analysis has been performed using a 3D optoelectric motion tracking system that utilizes active infrared LEDs and near-infrared sensors. The subject performed swing motion using a regular golf club and a soft golf club in turn. The obtained motion capture data was used to build a 3D computer simulation model to obtain left wrist, elbow shoulder and lumbar joint force and torque using inverse and forward dynamics calculations. The joint force and torque during soft golf swing were lower than regular golf swing. The analysis gave better understanding of the effectiveness of the soft golf club.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.7
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• pp.70-82
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• 1993

In this paper, employing the 3-dimensional discrete cosine transform (DCT) for the utilization of the temporal correlation, an adaptive motion sequence coding technique is proposed. The energy distribution in a 3-D DCT block, due to the nonstationary nature of the image data, varies along the veritical, horizontal and temporal directions. Thus, aiming an adaptive system to local variations, adaptive procedures, such as the 3-D classification, the classified linear scanning technique and the VLC table selection scheme, have been implemented in our approach. Also, a hybrid structure which adaptively combines inter-frame coding is presented, and it is found that the adaptive hybrid frame coding technique shows a significant performance gain for a moving sequence which contains a relatively small moving area. Through an intensive computer simulation, it is demonstrated that, the performance of the proposed 3-D transform coding technique shows a close relation with the temporal variation of the sequence to be code. And the proposed technique has the advantages of skipping the computationally complex motion compensation procedure and improving the performance over the 2-D motion compensated transform coding technique for rates in the range of 0.5 ~ 1.0 bpp.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.11
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• pp.1131-1135
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• 2010

This paper presents a method to capture the posture of the human lower-limbs on the 3D space by using a single camera and a planar mirror. The system estimates the pose of the camera facing the mirror by using four coplanar IR markers attached on the planar mirror. After that, the training space is set up based on the relationship between the mirror and the camera. When a patient steps on the weight board, the system obtains relative position between patients' feet. The markers are attached on the sides of both legs, so that some markers are invisible from the camera due to the self-occlusion. The reflections of the markers on the mirror can partially resolve the above problem with a single camera system. The 3D positions of the markers are estimated by using the geometric information of the camera on the training space. Finally the system estimates and visualizes the posture and motion of the both legs based on the 3D marker positions.

• Journal of Industrial Technology
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• v.25 no.A
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• pp.87-93
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• 2005

Three-dimensional ultrasonic probes being applied to the medical imaging can be grouped into three depending on the scanning methods, which are a mechanical type system, a free-hand system, and 2D phased arrays system. A mechanical type scanner uses a mechanically driven transducer to acquire series of 2D plane images. By integrating these images, a 3-D medical image can be constructed. A motor driving mechanism is a conventional choice for mechanically driving a transducer assembly which picks the raw ultrasonic images up. In this paper we attempt to design a 3D ultrasonic probe which has a operating mechanism of s tilting 3-D scanning. The motion of a transducer assembly of the ultrasonic probe is analytically modelled. We propose a selection procedure for the diameter of a wire rope driving the transducer assembly and the size of torsional spring which gives an initial tension to wire ropes.

• Journal of the Korea Convergence Society
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• v.1 no.1
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• pp.69-75
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• 2010

The importance of a using the visual media in English education has been increased. By an importance of Characters in English language content, the more effort is needed for a learner to show the English pronunciation and a realistic implementation. In this paper, we tried to review the Syntax-based Educational Contents Authoring System. For the more realistic lip-sync character, 3D character to enhance the efficiency of the education was constructed. We used a chart of the association structure analysis of mouth's shape. we produced an optimized 3D character through a process of a concept, a modeling, a mapping and an animating design. For more effective educational content for 3D character creation, the next research will be continuously a 3d Character added to a hand motion and body motion in order to show an effective communication example.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.395-398
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• 2002

In this paper, we propose a system that is configured with double stereo-visions to measure jaw movement. This new system measures not only left and right hinge points of jaw motion but also floating paths of hinge points during lateral and protrusive movement. The resulting 3D position and path data can also be used for 3D graphic simulation technique for occlusion diagnosis and therapy. The system also considers the compatibility with conventional occlusion therapy devices.