• Journal of Korea Water Resources Association
• /
• v.52 no.10
• /
• pp.743-752
• /
• 2019

The flow in the meandering channel is characterized by the spiral motion of secondary currents that typically cause the erosion along the outer bank. Hydraulic structures, such as spur dike and groyne, are commonly installed on the channel bottom near the outer bank to mitigate the strength of secondary currents. This study is to investigate the effects of submerged vanes installed in a $90^{\circ}$ meandering channel on the development of secondary currents through three-dimensional numerical modeling using the hybrid RANS/LES method for turbulence and the volume of fluid method, based on OpenFOAM open source toolbox, for capturing the free surface at the Froude number of 0.43. We employ the second-order-accurate finite volume methods in the space and time for the numerical modeling and compare numerical results with experimental measurements for evaluating the numerical predictions. Numerical results show that the present simulations well reproduce the experimental measurements, in terms of the time-averaged streamwise velocity and secondary velocity vector fields in the bend with submerged vanes. The computed flow fields reveal that the streamwise velocity near the bed along the outer bank at the end section of bend dramatically decrease by one third of mean velocity after the installation of vanes, which support that submerged vanes mitigate the strength of primary secondary flow and are helpful for the channel stability along the outer bank. The flow between the top of vanes and the free surface accelerates and the maximum velocity of free surface flow near the flow impingement along the outer bank increases about 20% due to the installation of submerged vanes. Numerical solutions show the formations of the horseshoe vortices at the front of vanes and the lee wakes behind the vanes, which are responsible for strong local scour around vanes. Additional study on the shapes and arrangement of vanes is required for mitigate the local scour.

• Cartoon and Animation Studies
• /
• s.33
• /
• pp.449-467
• /
• 2013

Contemporary 21st century, the rapid development of technology has achieved due to the emergence of various digital devices, a variety of media to the diversification of the limits of visual representation is reduced. Therefore, the combination of technology and art, visual arts, giving limits of getting it free to the public will feel fresh new visual impact. Such a new approach to light of a combination of technology and art, a variety of fine art and motion picture of the visual arts, such as has been recognized as a new genre. Of the resolution of the projector by utilizing the current reality and unreality beyond the boundaries of the building or structure in the city, as a schematic design of the screen projected structure and mapping of the art technology in an attempt to integrate recent has been studied in various ways. The projected structure design and the mapping of the art technology in an attempt to incorporate recent research has been diverse. In this study, as a new technology of a projection mapping to study the technique of looking for the definition of mapping practices to maximize the effectiveness of Visual Perception 3D animation was applied to a case study. A combination of 3D animation and project mapping in the future the fusion of art and technology to meet the zeitgeist with new possibilities of visual art to create synergies that is expected.

• Magazine of the Korea Concrete Institute
• /
• v.10 no.6
• /
• pp.241-252
• /
• 1998

The objective of the research stated herein is to observe the actual responses of a low-rise nonseismic moment-resisting reinforced concrete frame subjected to varied levels of earthquake ground motions. First, the reduction scale for the model was determined as 1 : 5 considering the capacity of the shaking table to be used and the model was manufactured according to the similitude law. This model was, then, subjected to the shaking table motions simulating Taft N21E component earthquake ground motions, whose peak ground accelations (PGAs) were modified to 0.12g, 0.2g, 0.3g, and 0.4g. The lateral accelerations and displacements at each story and local deformations at the critical reginos of the structure were measured. The base shear was measured by using self-made load cells. Before and after each earthquake simulation test, free vibration tests were performed to find the change in the natural period and damping ratio of the model. The test data on the global and local behaviors are interpreted. The model showed the linear elastic behavior under the Taft N21E motion with the PGA if 0.12g, which represents the design earthquake in Korea. The maximum base shear was 1.8tf, approximately 4.7 times the design base shear. The model revealed fairly good resistance to the higher level of earthquake simulation tests. The main components of its resistance to the high level of earthquakes appeared to be 1) the high overstrength, 2) the elongation of the fundamental period, and 3) the minor energy dissipation by inelastic deformations. The drifts of the model under these tests were approximately within the allowable limit.

• Clinical and Experimental Reproductive Medicine
• /
• v.21 no.1
• /
• pp.1-11
• /
• 1994

The occurrence and time course of capacitation, acrosomal loss, and hyperactivated motility require quantitative definition in order to characterize fertile human sperm. Recently the method has been developed to estimate the quality of spermatozoa by using kinematic parameters such as curvilinear velocity(VCL), average path velocity(VAP), linearity(LIN), straightness(STR), amplitude of lateral head displacement(ALH), and beat cross frequence(BCF) from Computer Assisted Sperm Analysis (CASA). In this study, using the Hamilton Thorn motility analyzer HTM 2030(Hamilton Thorn Research, Beverly, MA), we attempted to identify the spermatozoa with hyperactivated motility (HA) objectively and to monitor hyperactivation of human spermatozoa during incubation in capacitating media and after treatment of calcium ionophore as compared with acrosome status. And we examined whether HA are related to the result of SPA. Semen samples obtained from 16 healthy men were prepared by swim up technique and preincubated in a capacitating media(modified BWW medium) for 5 hours and treated with calcium ionophore solution. The acrosome reaction was detected with PSA-FITC labelling of the acrosome and in vitro sperm ferilizing capacity was assessed by the zona free hamster ovum penetration assay (SPA). The incidence of hyperactivated sperm was 2.6% in fresh semen, 14.3% of the swim up population, 13.7% after 5h of incubation. Significant increase of percentage of hyperactivated sperm was observed after the incubation (p<0.05) but after treatment, no significant changes of percentage of hyperactivated sperm(l1.8%) in contrast to significant rise in the percentage of acrosome reacted cells. Correlation analysis failed to show any significant relationship between the percentage of sperm with HA and SPA score. In conclusion, although no direct correlations were found between the results of SPA and HA, hyperactivation of sperm is associated with capacitation and monitoring hyperactivated sperm will be expected as a method of evaluating the functional quality of sperm such as SPA.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.7 no.4
• /
• pp.192-198
• /
• 2004

A numerical method is developed to solve a two-dimensional diffraction problem for a body located in a sediment pocket where a heavier muddy water is trapped. In the present study, the wave exciting forces acting on a submerged body in the water-sediment interface by an incident wave is investigate. It is assumed that the heavier mud is trapped locally in a sediment pocket. A mathematical formulation is made in the scope of the potential theory. The fluid is assumed to be inviscid, incompressible and its motion irrotational. The boundary conditions on the unknown free surface and interface are linearized. As a method of solution, the localized finite-element method is adopted. In the method, the computation domain is reduced by utilizing the complete set of analytic solutions known in the infinite subdomain to be truncated by introduction of an appropriate juncture conditions. The main advantage of this method is that any complex geometry of the boundaries can be easily accommodated. Computations are carried out for mono-chromatic plane progressive surface waves normally incident on the domain. Numerical results are compared with those obtained by Lassiter based on Schwingers variational method. Good Agreements are obtained in general. Another numerical computations are made for the cases with and without a body in the sediment pocket.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.9
• /
• pp.825-837
• /
• 2017

This paper describes a novel type of a walking rehabilitation robot that applies robot technologies to crutches used by patients with walking difficulties in the lower body. The primary features of the developed robot are divided into three parts. First, the developed robot is worn on the patient's chest, as opposed to the conventional elbow crutch that is attached to the forearm; hence, it can effectively disperse the patient's weight throughout the width of the chest, and eliminate the concentrated load at the elbow. Furthermore, it allows free arm motion during walking. Second, the developed robot can recognize the walking intention of the patient from the magnitude and direction of the ground reactive forces. This is done using three-axis force sensors attached to the feet of the robot. Third, the robot can perform a stair walking function, which can change vertical movement trajectories in order to step up and down a single stair according to the floor height. Consequently, we experimentally showed that the developed robot can effectively perform walking rehabilitation assistance by perceiving the walking intention of the patient. Moreover we quantitatively verified muscle power assistance by measuring the electromyography (EMG) signals of the muscles of the lower limb.

• Archives of Reconstructive Microsurgery
• /
• v.6 no.1
• /
• pp.73-79
• /
• 1997

Complete denervation after severe brachial plexus injury make significant muscle atrophy with loss of proper function. It is much helpful to reconstruct the essential function of the elbow flexion movement in patient with total loss of elbow flexion motion after brachial plexus lesion which was not recovered with nerve surgery or long term conservative treatment from onset. In whole arm type brachial plexus injury, if there were no response to neurotization or neglected from injury, the volume of the denervated muscle is significantely reduced month by month. About 18 months most of the muscle fibers change to fibrous tissues and markedly atrophied irreversibly, further waiting is no more meaningful from that period. Authors performed 14 cases of functioning gracilis muscle transfer from 1981 to 1995 with microneurovascular technique, neuromusculocutaneous free flaps were performed for reconstruction of lost elbow flexion function. Average follow-up period was 5 years and 6 months. We used couple of intercostal nerves as a recipient nerve which were anastomosed to muscular nerve from obturator nerve in all cases. Recipient vessels were three deep brachial artery and eleven brachial artery which were anastomosed to medial femoral circumflex artery with end to end or end to side fashion. Average resting length of the transplanted gracilis were 24 cm. We can get average 54 degree flexion range of elbow with fair muscle power from flail elbow. There were one case of muscle necrosis with lately developed thrombosis of microvascular anastomosed site which comes from insufficient recipient arterial condition, 3 cases of partial marginal necrosis of distal skin of the transplanted part which were not significant problem with spontaneously solved with time goes by gracilis muscle has constant neurovascular pattern with relatively easy harvesting donor with minimal donor morbidity. Especially it has similar length and shape with biceps brachii muscle of upper arm and longer nerve pedicle which can neurorrhaphy with intercostal nerve without nerve graft if sufficient mobilization of the nerves from both sides of gracilis and intercostal region. Authors can propose gracilis muscle transplantation with intercostal nerves neurotization is helpful method with minimal donor morbidity for neglected brachial plexus palsy patients.

• Korean Journal of Applied Biomechanics
• /
• v.23 no.4
• /
• pp.285-294
• /
• 2013

The purpose of this study was to provide fundamental information for success factors of techniques through kinematic analysis including coordination of lower extremities and landing stability according to the success and failure of $540^{\circ}$ Dwihuryeochagi in Taekwondo. Twenty Taekwondo athletes: ten success group (S, age: $22.3{\pm}1.8$ yrs, height: $172.1{\pm}5.4$ cm, body mass: $64.4{\pm}4.2$ kg) and ten failure group (F, age: $22.3{\pm}1.8$ yrs, height: $172.1{\pm}5.4$ cm, body mass: $64.4{\pm}4.2$ kg) participated in this study. Three-dimensional motion analysis using a system of 3 video cameras with a sampling of 60 fields/s was performed during the competition of $540^{\circ}$ Dwihuryeochagi. Motions were divided into five events: pivot foot landing (E1), pivot foot toe off (E2), COM max height (E3), kick impact (E4) and landing (E5). At E1, the stride width was greater for S than for F (p<.05) while the time was greater for S than for F during P4 (p<.05). At E4, knee angle was greater for S than for F (p<.05). At E5, hip angle was greater for S than for F (p<.05) while kick distance was greater for S than for F (p<.05). Furthermore, at P3, the time would be related to kicking velocity (p<.05), while at P4, the time, range of hip angle and knee angle would be related to kick distance (p<.05). At P1, COM horizontal velocity would be related to COM vertical velocity of P1 and P2 (p<.05). Based on the findings, success factors of $540^{\circ}\acute{y}$ Dwihuryeochagi were COM horizontal velocity of P1, COM vertical velocity of P2, the time, kick distance, velocity, angle of lower extremities and coordination of P3-P4.

• The Journal of the Korean bone and joint tumor society
• /
• v.11 no.1
• /
• pp.100-104
• /
• 2005

Osteosarcoma is the most common tumor in malignant bone tumors. The peak age incidence in osteosarcoma is between 10 to 14 years of age. This tumor rarely develops under 6 years of age and the youngest patient in the previous literature was a 13 months old girl who had an osteosarcoma involving the second metacarpal bone. We report a case of an 8 month old male infant, who had an osteosarcoma involving the right proximal tibia. This patient was treated by wide excision with transepiphyseal resection and reconstruction with allograft. At 20 months after operation, the varus deformity was developed at the proximal junctional site of allograft. Thereafter, the revision was performed with correction of deformity and augmentation with the proximal fibula transfer. At 51 months after operation, he has been remained as free of disease, and he has recovered the knee motion ranged from 15 degree to 75 degree. The osteosarcoma in infant is very rare but it should be considered the osteosarcoma in the differential diagnosis of any bone lesion. Instead of amputation, the limb sparing operation and the solutions for limb length inequility in growing period should be carefully considered in the infantile osteosarcoma.

• Journal of KIISE:Software and Applications
• /
• v.32 no.3
• /
• pp.181-191
• /
• 2005

This article describes a simplified mathematical model and the relevant numerical algorithm to simulate the draped cloth on virtual human body. The proposed algorithm incorporates an elliptical, or non-consecutive, method to simulate the cloth wrinkles on moving bodies without resorting to the result of the past time-steps of drape simulation. A global-local analysis technique was employed to decompose the drape of cloths into the global deformation and the local wrinkles that will be superposed linearly The global deformation is determined directly by the rotation and the translation of body parts to generate a wrinkle-free yet globally deformed shape of cloth. The local wrinkles are calculated by solving simple elliptical equations based on the orthogonality between conjugate harmonic functions representing the wrinkle amplitude and the direction of wrinkles. The proposed method requires no interpolative time frames even for discontinuous body postures. Standing away from the incremental approach of time integration in conventional methods, the proposed method yields a remarkable reduction of CPU time and an enhanced stability. Also, the transient motion of cloth could be achieved by interpolating between the deformations corresponding to each static posture.