• The Journal of the Korea Contents Association
• /
• v.12 no.8
• /
• pp.20-28
• /
• 2012

DVC(Distributed Video Coding) technique is a new paradigm, which is based on the Slepian-Wolf and Wyner-Ziv theorems. DVC offers not only flexible partitioning of the complexity between the encoder and decoder, but also robustness to channel errors due to intrinsic joint source-channel coding. Many conventional research works have been focused on the light video encoder and its rate-distortion performance improvement. However, in this paper, we propose a new DVC codec which is effectively applicable for error-prone environment. The proposed method adopts a quantiser without dead-zone and symmetric Gray code around zero value. Through computer simulations, the proposed method is evaluated by the bit errors position as well as the number of burst bit errors. Additionally, it is shown that the maximum and minimum transmission rate for the given application can be linearly determined by the number of bit errors.

• Journal of Broadcast Engineering
• /
• v.1 no.2
• /
• pp.176-187
• /
• 1996

This paper deals with the accurate estimation of 3- D pose (position and orientation) of a moving object with reference to the world frame (or robot base frame), based on a sequence of stereo images taken by cameras mounted on the end - effector of a robot manipulator. This work is an extension of the previous work[1]. Emphasis is given to the 3-D pose estimation relative to the world (or robot base) frame under the presence of not only the measurement noise in 2 - D images[ 1] but also the camera position errors due to the random noise involved in joint angles of a robot manipulator. To this end, a new set of discrete linear Kalman filter equations is derived, based on the following: 1) the orientation error of the object frame due to measurement noise in 2 - D images is modeled with reference to the camera frame by analyzing the noise propagation through 3- D reconstruction; 2) an extended Jacobian matrix is formulated by combining the result of 1) and the orientation error of the end-effector frame due to joint angle errors through robot differential kinematics; and 3) the rotational motion of an object, which is nonlinear in nature, is linearized based on quaternions. Motion parameters are computed from the estimated quaternions based on the iterated least-squares method. Simulation results show the significant reduction of estimation errors and also demonstrate an accurate convergence of the actual motion parameters to the true values.

• Journal of Broadcast Engineering
• /
• v.26 no.5
• /
• pp.519-532
• /
• 2021

Recently, in various fields such as games, movies, and animation, content that uses motion capture to build body models and create characters to express in 3D space is increasing. Studies are underway to generate animations using RGB-D cameras to compensate for problems such as the cost of cinematography in how to place joints by attaching markers, but the problem of pose estimation accuracy or equipment cost still exists. Therefore, in this paper, we propose a system that inputs RGB images into a joint estimation network and converts the results into 3D data to create FBX format animations in order to reduce the equipment cost required for animation creation and increase joint estimation accuracy. First, the two-dimensional joint is estimated for the RGB image, and the three-dimensional coordinates of the joint are estimated using this value. The result is converted to a quaternion, rotated, and an animation in FBX format is created. To measure the accuracy of the proposed method, the system operation was verified by comparing the error between the animation generated based on the 3D position of the marker by attaching a marker to the body and the animation generated by the proposed system.

• Journal of the Korean Society of Physical Medicine
• /
• v.4 no.2
• /
• pp.93-100
• /
• 2009

Purpose：The purpose of this study was to examine the effects of self-controlled knowledge of result (KR) versus the yoked KR on learning of knee joint proprioception. Methods：Forty volunteer subjects (20 men and 20 women) were randomly assigned to each four groups: 1) self-controlled KR in open kinematic chain, 2) yoked KR in open kinematic chain, 3) self controlled KR in close kinematic chain, and 4) yoked KR in close kinematic chain. The difference between the angle of position and reproduction angle was determined as a proprioception error and measured using an angle reproduction test. The subjects in self-controlled groups were provided with feedback whenever they requested it, whereas the subjects in yoked groups were not provided with feedback. The data were analyzed using a one-way ANOVA. Results：The proprioception errors in close kinematic chain groups decreased significantly compared with those in close kinematic chain groups(p<.05). The proprioception errors in the self-controlled group decreased significantly compared with those in yoked groups during acquisition and retention test(p<.05). Conclusion：Self-controlled knowledge of result during open kinematic chain movement is considered to be a good method on motor learning.

• Physical Therapy Korea
• /
• v.24 no.3
• /
• pp.21-29
• /
• 2017

Background: The measurement of the strength of the shoulder muscles is an important element of the overall assessment of patients with various shoulder disorders. However, the clinical utilization of this measurement is dependent on its reproducibility. Objects: To explore the reproducibility of the measurements derived from testing of the isokinetic strength of shoulder muscles in patients with tendinitis of the rotator cuff. Methods: A total of 20 patients with tendinitis of the rotator cuff participated in this study and were assessed twice in 1 week. Isokinetic testing was performed concentrically for shoulder flexors, abductors, and external rotators and eccentrically for the shoulder extensors, adductors, and internal rotators. The relative and absolute reproducibility of the peak torque (PT) and ratios were assessed using intra-class correlation coefficients (ICC), standard error of measurement (SEM), and minimal clinically important difference (MCID), respectively. Results: Overall, high to excellent ICC, clinically acceptable SEM and MCID values were obtained for the PT (ICC: .83-.95, SEM: 1.2%-9%, MCID: 3.4%-25%) and ratios (ICC: .85-.93, SEM: 5.1%-10%, MCID: 14.2%-27.6%). Conclusion: These findings suggest that isokinetic tests may be effectively utilized for the determination of shoulder strength profiles and appropriate position are recommended to perform test without pain in patients with tendinitis of the rotator cuff.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.576-583
• /
• 2000

A robust position control using a sliding mode controller is adopted for the stable dynamic walking of the biped. For the biped robot that is modeled with 14 degrees of freedom rigid bodies using the method of the multibody dynamics, the joint angles for simulation are obtained by the velocity transformation matrix using the given Cartesian foot and trunk trajectories. Hertz force model and Hysteresis damping element which is used in explanation of the energy dissipation during contact with ground are used for modeling of the ground reactions during the simulation. By the obtained that forces which contains highly confused noise elements and the system modeling uncertainties of various kinds such as unmodeled dynamics and parameter inaccuracies, the biped system will be unstable. For that problems, we are adopting a nonlinear robust control using a sliding mode controller. Under the assumption that the esimation error on the unknown parameters is bounded by a given function, that controller provides a successful way to preserve stability and achieve good performance, despite the presence of strong modeling imprecisions or uncertainties.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.4
• /
• pp.1373-1391
• /
• 2022

We investigate mobile multiple-input multiple-output (MIMO) molecular communication via diffusion (MCvD) system which is consisted of two source nodes, two destination nodes and one relay node in the mobile three-dimensional channel. First, the combinations of decode-and-forward (DF) relaying protocol and network coding (NC) scheme are implemented at relay node. The adaptive thresholds at relay node and destination nodes can be obtained by maximum a posteriori (MAP) probability detection method. Then the mathematical expressions of the average bit error probability (BEP) of this mobile MIMO MCvD system based on DF and NC scheme are derived. Furthermore, in order to minimize the average BEP, we establish the optimization problem with optimization variables which include the ratio of the number of emitted molecules at two source nodes and the initial position of relay node. We put forward an iterative scheme based on block coordinate descent algorithm which can be used to solve the optimization problem and get optimal values of the optimization variables simultaneously. Finally, the numerical results reveal that the proposed iterative method has good convergence behavior. The average BEP performance of this system can be improved by performing the joint optimizations.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.2C
• /
• pp.139-147
• /
• 2010

A novel turbo coded modulation scheme, called turbo-APPM, for deep space optical communications is constructed. The constructed turbo-APPM is a serial concatenations of turbo codes, an accumulator and a pulse position modulation (PPM), where turbo codes act as an outer code while the accumulator and the PPM act together as an inner code. The generator polynomial and the puncturing rule for generating turbo codes are chosen to show the low bit error rate. At the receiver, the joint decoding is performed by exchanging soft information iteratively between the inner decoder and the outer decoder. In the outer decoder, a local iterative decoding for turbo codes is conducted before transferring soft information to the inner decoder. Poisson distribution is used to model the deep space optical channel. It is shown by simulations that the constructed turbo-APPM provides coding gains over all previously proposed schemes such as LDPC-APPM, RS-PPM and SCPPM.

• The Journal of Korean Physical Therapy
• /
• v.32 no.2
• /
• pp.88-93
• /
• 2020

Purpose: This study examined the inter-rater reliability of cervical proprioception, dynamic balance ability, and ankle dorsiflexion range of motion using STARmat^®, which is a practical clinical tool that can provide practitioners and patients with quantitative and qualitative results. Methods: Thirty healthy young subjects were enrolled in this study, and two well-trained physical therapists participated as a tester. Two testers measured the cervical joint position error at the starting position after neck flexion, extension, side bending, and rotation; three dynamic balance tests, including anterior excursion, anterior reaching with single leg balance, and posterior diagonal excursion; and ankle dorsiflexion range of motion using STARmat^®. The intra-class correlation coefficient (ICC) was used to determine the inter-rater reliability of the tests. Results: The inter-rater reliability for the cervical proprioception ranged from moderate to good (0.66 to 0.83), particularly for flexion (0.82), extension (0.70), right side bending (0.73), left side bending (0.71), right rotation (0.83), and left rotation (0.66). For the dynamic balance, the inter-rater reliability ranged from good to excellent (0.87 to 0.91), particularly for anterior excursion (0.86), posterior diagonal excursion (0.87 to 0.89), and anterior reaching with a single leg balance (0.90 to 0.91). In addition, for the ankle dorsiflexion range of motion, the ICC for the inter-rater reliability ranged from 0.95 to 0.96. Conclusion: STARmat^® is a reliable tool for measuring cervical proprioception, dynamic balance tests, and ankle dorsiflexion range of motion in healthy young adults.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.10 no.1
• /
• pp.65-72
• /
• 2010

For developing navigation system of total hip arthroplasty (THA) and evaluating hip joint kinematics, 3-D pose position of the femur and acetabulum in the pelvic coordinate system has been quantified. The pelvic coordinate system is determined by manually indicating pelvic landmarks in multidetector-row computed tomography (MDCT) images. It includes intra- and inter-observer variability, and may result in a variability of THA operation or diagnosis. To reduce the variability of pelvic coordinate system determination, this paper proposes an automated method in MDCT images. The proposed method determines pelvic coordinate system automatically by detecting pelvic landmarks on anterior pelvic plane (APP) from MDCT images. The method calibrates pelvic pose by using silhouette images to suppress the affect of pelvic pose change. As a result of comparing with manual determination, the proposed method determined the coordinate system with a mean displacement of $2.6\;{\pm}\;1.6$ mm and a mean angle error of $0.78\;{\pm}\;0.34$ deg on 5 THA subjects. For changes of pelvic pose position within 10 deg, standard deviation of displacement was 3.7 mm, and of pose was 1.28 deg. We confirmed the proposed method was robust for pelvic pose changes.