• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.2
• /
• pp.193-200
• /
• 2002

Simple spring-damper-mass models have been widely used to investigate whole-body vortical biodynamic response characteristics of the seated vehicle driver. Most previous models have not considered the effect of wobbling masses; i.e. heart, lungs, liver, intestine, etc. In this study, 4 -DOF seated driver model including one non-rigid mass representing wobbling visceral mass, 5-DOF model including intestine, and 10-DOF model including five lumbar vertebral masses were proposed. The model parameters were identified by a combinatorial optimization technique. simulated annealing method. The objective function was chosen as the sum of error between model response of seat-to-head transmissibility and driving point mechanical impedance and those of experimental data for subjects seated erect without backrest support. The model response showed a good agreement with the experimental response characteristics. Using a 10-DOF model, calculated resonance frequency of lumbar spine at 4Hz was matched well with experimental results of Panjabi et al.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.2
• /
• pp.130-136
• /
• 2010

For stability analysis of the lumbar spine, the hypothesis presented is that the disc has stress sensors driving feedback mechanism, which could react to the imposed loads by adjusting the contraction of the muscles. Fusion in the motion segment of the lumbar spinal column is believed to alter the stability of the spinal column. To identify this effect finite element (FE) models combined with optimization technique was applied and quantify the role of each muscle and reaction forces in the spinal column with respect to the fusion level. The musculoskeletal FE model was consisted with detailed whole lumbar spine, pelvis, sacrum, coccyx and simplified trunk model. Vertebral body and pelvis were modeled as a rigid body and the rib cage was constructed with rigid truss element for the computational efficiency. Spinal fusion model was applied to L3-L4, L4-L5, L5-S1 (single level) and L3-L5 (two levels) segments. Muscle architecture with 46 local muscles was used as acting directions. Minimization of the nucleus pressure deviation and annulus fiber average axial stress deviation was selected for cost function. As a result, spinal fusion produced reaction changes at each motion segment as well as contribution of each muscle. Longissimus thoracis and psoas major muscle showed dramatic changes for the cases of L5-S1 and L3-L5 level fusion. Muscle force change at each muscle also generated relatively high nucleus pressure not only at the adjacent level but at another level, which can explain disc degeneration pattern observed in clinical study.

• Asian Spine Journal
• /
• v.12 no.6
• /
• pp.998-1009
• /
• 2018

Study Design: Olfactory ensheathing cells (OECs) from rat olfactory mucosa were cultured, characterized, and transplanted into a rat model of spinal cord injury (SCI). Purpose: To evaluate different doses of OECs in a rat model of SCI. Overview of Literature: SCI causes permanent functional deficit because the central nervous system lacks the ability to perform spontaneous repair. Cell therapy strategies are being explored globally. The clinical use of human embryonic stem cell is hampered by ethical controversies. Alternatively, OECs are a promising cell source for neurotransplantation. This study aimed to evaluate the efficacy of different doses of allogenic OEC transplantation in a rat model of SCI. Methods: OECs were cultured from the olfactory mucosa of Albino Wistar rats; these cells were characterized using immunohistochemistry and flow cytometry. Rats were divided into five groups (n=6 rats each). In each group, different dosage ($2{\times}10^5$, $5{\times}10^5$, $10{\times}10^5$, and >$10{\times}10^5$) of cultured cells were transplanted into experimentally injured spinal cords of rat models. However, in the SCI group, only DMEM (Dulbecco's modified Eagle's medium) was injected. Rats were followed up upto 8 weeks post-transplantation. The outcome of transplantation was assessed using the Basso, Beattie, Bresnahan (BBB) scale; motor-evoked potential studies; and histological examination. Results: Cultured cells expressed 41% of p75NTR, a marker for OEC, and 35% of anti-fibronectin, a marker for olfactory nerve fibroblast. These cells also expressed $S100{\beta}$ and glial fibrillary acid protein of approximately 75% and 83%, respectively. All the transplanted groups showed promising BBB scores for hind-limb motor recovery compared with the SCI group (p<0.05). A motor-evoked potential study showed increased amplitude in all the treated groups compared with the SCI. Green fluorescent protein-labeled cells survived in the injured cord, suggesting their role in the transplantation-mediated repair. Transplantation of $5{\times}10^5$ cells showed the best motor outcomes among all the doses. Conclusions: OECs demonstrated a therapeutic effect in rat models with the potential for future clinical applications.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.5
• /
• pp.548-553
• /
• 2014

In order to evaluate the performance of arrow that manufactures through production process, it is used that personal experiences such as hunters who have been using bow and arrow for a long time, technicians who produces leisure and sports equipment, and experts related with this industries. Also, the intensity of arrow's impact point which obtains from repeated shooting experiments is an important indicator for evaluating the performance of arrow. There are some ongoing researches for evaluating performance of arrow using intensity of the arrow's impact point and the arrow's flying image that obtained from high-speed camera. However, the research that deals with mutual relation between distribution of the arrow's impact point and characteristics of the arrow (length, weight, spine, overlap, straightness) is not enough. Therefore, this paper suggests both the system that could describes the distribution of the arrow's impact point into numerical representation and the correlation model between characteristics of arrow and impact points. The inputs of the model are characteristics of arrow (spine, straightness). And the output is MAD (mean absolute distance) of triangular shaped coordinates that could be obtained from 3 times repeated shooting by changing knock degree 120. The input-output data is collected for learning the correlation model, and ANN (artificial neural network) is used for implementing the model.

• Korean Journal of Radiology
• /
• v.25 no.4
• /
• pp.363-373
• /
• 2024

Objective: To develop and evaluate a deep learning model for automated segmentation and detection of bone metastasis on spinal MRI. Materials and Methods: We included whole spine MRI scans of adult patients with bone metastasis: 662 MRI series from 302 patients (63.5 ± 11.5 years; male:female, 151:151) from three study centers obtained between January 2015 and August 2021 for training and internal testing (random split into 536 and 126 series, respectively) and 49 MRI series from 20 patients (65.9 ± 11.5 years; male:female, 11:9) from another center obtained between January 2018 and August 2020 for external testing. Three sagittal MRI sequences, including non-contrast T1-weighted image (T1), contrast-enhanced T1-weighted Dixon fat-only image (FO), and contrast-enhanced fat-suppressed T1-weighted image (CE), were used. Seven models trained using the 2D and 3D U-Nets were developed with different combinations (T1, FO, CE, T1 + FO, T1 + CE, FO + CE, and T1 + FO + CE). The segmentation performance was evaluated using Dice coefficient, pixel-wise recall, and pixel-wise precision. The detection performance was analyzed using per-lesion sensitivity and a free-response receiver operating characteristic curve. The performance of the model was compared with that of five radiologists using the external test set. Results: The 2D U-Net T1 + CE model exhibited superior segmentation performance in the external test compared to the other models, with a Dice coefficient of 0.699 and pixel-wise recall of 0.653. The T1 + CE model achieved per-lesion sensitivities of 0.828 (497/600) and 0.857 (150/175) for metastases in the internal and external tests, respectively. The radiologists demonstrated a mean per-lesion sensitivity of 0.746 and a mean per-lesion positive predictive value of 0.701 in the external test. Conclusion: The deep learning models proposed for automated segmentation and detection of bone metastases on spinal MRI demonstrated high diagnostic performance.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.8
• /
• pp.157-163
• /
• 2004

Scoliosis is a complex musculoskeletal dieses requiring 3-D treatment with surgical instrumentation. To investigate the effects of correction surgery, a finite element model of personalized model of the scoliotic spine that will allow the design of clinical test providing optimal estimation of the post-operation results was developed. Three dimensional skeletal parts, such as vertebrae, clavicle and scapular were modeled as rigid bodies with keeping their morphologies. Kinematical joints and spring elements were adapted to represent the inter-vertebral disc and ligaments respectively. With this model, two types of surgery procedure, distraction procedure with Harrington device and rod derotation procedure with pedicle screw and rod system had been carried out. The obtained simulation results were comparatively corresponding to the post operational outcomes and successfully demonstrated qualitative analysis of surgical effectiveness. From this analysis, it has been found that the preparing of appropriate rod curvature and its insertion was more important than just performing the excessive derotation for scoliosis correction.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.3
• /
• pp.139-150
• /
• 2000

Although a number of neck injuries are generated, the data which quantify the kinematic response of the human head and cervical spine in low-speed rear-end automobile collisions is very limited. On this problem, just few in vitro experimental research or some experimental research using dummy on neck injury by rear-end collision was conducted, thus systematic research is requested on full scale injury mechanism. An occupant model for the response of the occupant subject to rear-end collision using commercial dynamics package DADS was developed. Developed model shows more close agreement with the experimental data compared with the MADYMO simulation results for the cases of ${\delta}V=16$ kph in sled test. For the case of ${\delta}V=8$ kph and 33.5 kph with production seat, model also shows its reliable response compared with experimental results using Hybrid III and Hybird III with RID.

• Journal of Korean Neurosurgical Society
• /
• v.60 no.3
• /
• pp.348-354
• /
• 2017

Objective : To identify and investigate differences in spinal fusion between the normal and osteopenic spine in a rat model. Methods : Female Sprague Dawley rats underwent either an ovariectomy (OVX) or sham operation and were randomized into two groups: non-OVX group and OVX group. Eight weeks after OVX, unilateral lumbar spinal fusion was performed using autologous iliac bone. Bone density (BD) was measured 2 days and 8 weeks after fusion surgery. Microcomputed tomography was used to evaluate the process of bone fusion every two weeks for 8 weeks after fusion surgery. The fusion rate, fusion process, and bone volume parameters of fusion bed were compared between the two groups. Results : BD was significantly higher in the non-OVX group than in the OVX group 2 days and 8 weeks after fusion surgery. The fusion rate in the non-OVX group was higher than that in the OVX group 8 weeks after surgery (p=0.044). The bony connection of bone fragments with transverse processes and bone formation between transverse processes in non-OVX group were significantly superior to those of OVX group from 6 weeks after fusion surgery. The compactness and bone maturation of fusion bed in non-OVX were prominent compared with the non-OVX group. Conclusion : The fusion rate in OVX group was inferior to non-OVX group at late stage after fusion surgery. Bone maturation of fusion bed in the OVX group was inferior compared with the non-OVX group. Fusion enhancement strategies at early stage may be needed to patients with osteoporosis who need spine fusion surgery.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.10
• /
• pp.1205-1210
• /
• 2011

Spinal instability known to be related to low back pain. However, the quantitative definition of spinal instability has not been established because there is a lack of consensus regarding clinical and radiological studies. In addition, the major factors affecting such instability have not been elucidated, although disc degeneration, disc injury, ligament injury, and isthmic defects are considered to result in such problems. In this study, individual and combined influences on spinal instability with a three-dimensional finite element model of a one-level lumbar spinal motion segment were investigated, under the assumption that the rotation and translation in the sagittal plane under flexion and extension represented the instability indices. The results could be helpful in understanding the causes and mechanisms of spinal instability in the lumbar spine.

• Journal of Korean Physical Therapy Science
• /
• v.6 no.2
• /
• pp.1041-1062
• /
• 1999

This study is to stimulate the model of which top notch muscle stimuli physical therapy has been made on the basis of GCM. GCM has been studied on the hypermobility & hypomobility pattern on the part of spine & extremity, and the body characteristics of four body types, which is the tilting of seal scapular & ilium. The purpose of this study is to analysize the type of GCM which has been focused on the spine & extremity for the patients having dysfunctions of neuromuscular system, being analysized the movement. The result of this study is as following; 1) The First hypothesis: The hypermobility & hypomobility pattern assorted by the tilting of scapular & ilium, as does the former study analysize was claimed that it would be in line with the pattern for hypermobility hypomobility and physical characteristics according to each body type at the percentage of at least 60(p<.001). 2) The 2nd hypothesis : Stimuli therapy of muscle dealing with physical characteristics and joint hypermobility hypomobility has the important role in restoring the deformity and keeping anatomical postural plumb alignment also it would a highly effects on correcting the body even though the stimuli area was limited to four areas and it was lack of time compared with those applied by general physical therapy(p<.001). As above the result, the top-notch type for physical therapy based on hypermobility hypomobility pattern by 4 body types which has been studied on tilting of scapular & ilium is more specificed and specialized than those of general physical therapy technologies. So this study will be believed to dedicate to restoration ideal anatomical postural plumb alignment based on spinal Manipulation and the concept of whole person as well as to being simple and effective to apply.