• Journal of Convergence for Information Technology
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• v.9 no.8
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• pp.140-147
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• 2019

The purpose of this study is to find biomechanical parameters for optimal shoes production through an ergonomic usability assessment of five existing types of shoes preferred by B-BOY. Ten experts and ten non-experts participated in the experiment, and 12 infrared cameras (Qualis, Oqus), force plate (Kistler, 9286AA) and foot pressure plate (Zebris Gmbh, Zebris PDM-System) were used to obtain the data. The results of the study are as follows. First, P shoes with a friction coefficient of 0.38 and a free moment of 0.32 N/m/kg are desirable in terms of traction capability and safety. Second, on the cushion, it was found that the N shoes 2.51 N, sec/kg and non-expert, and 2.86 N and sec/kg were suitable. Third, it is deemed appropriate for C shoes with a forefoot average pressure of 10.11 KPa (right), 10.05 KPa (left), and V shoes with a rearfoot average pressure of 8.4 KPa (right) and 8.36 KPa (left). In conclusion, the combination of the structure and material of V shoes should be developed for traction and stability, N shoes for cushion, and walking balance for C and V shoes.

• Journal of Biomedical Engineering Research
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• v.43 no.5
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• pp.308-318
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• 2022

The purpose of this study is to evaluate the biomechanical properties of fractured adjacent soft tissue during closed reduction after forearm fracture using the finite element method. To accomplish this, a finite element (FE) model of the forearm including soft tissue was constructed, and the material properties reported in previous studies were implemented. Based on this, nine finite element models with different fracture types and fracture positions, which are the main parameters, were subjected to finite element analysis under the same load and boundary conditions. The load condition simulated the traction of increasing the fracture site spacing from 0.4 mm to 1.6 mm at intervals of 0.4 mm at the distal end of the radioulnar bone. Through the finite element analysis, the fracture type, fracture location, and displacement were compared and analyzed for the fracture site spacing of the fractured portion and the maximum equivalent stress of the soft tissues adjacent to the fracture(interosseous membrane, muscle, fat, and skin). The results of this study are as follows. The effect of the major parameters on the fracture site spacing of the fractured part is negligible. Also, from the displacement of 1.2 mm, the maximum equivalent stress of the interosseous membrane and muscle adjacent to the fractured bone exceeds the ultimate tensile strength of the material. In addition, it was confirmed that the maximum equivalent stresses of soft tissues(fat, skin) were different in size but similar in trend. As a result, this study was able to numerically confirm the damage to the adjacent soft tissue due to the fracture site spacing during closed reduction of forearm fracture.

• 한국체육학회지인문사회과학편
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• v.57 no.6
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• pp.293-308
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• 2018

This study was carried out to investigate the current trends in skiing-related research from existing literature in the field of kinematics, measurement sensor and computer simulation. In the field of kinematics, research is being conducted on the mechanism of ski turn, posture analysis according to the grade and skill level of skiers, friction force of ski and snow, and air resistance. In the field of measurement sensor and computer simulation, researches are being conducted for researching and developing equipment using IMU sensor and GPS. The results of this study are as follows. First, beyond the limits of the existing kinematic analysis, it is necessary to develop measurement equipment that can analyze the entire skiing area and can be deployed with ease at the sports scene. Second, research on the accuracy of information obtained using measurement sensors and various analysis techniques based on these measures should be carried out continuously to provide data that can help the sports scene. Third, it is necessary to use computer simulation methods to clarify the injury mechanism and discover ways to prevent injuries related to skiing. Fourth, it is necessary to provide optimized ski trajectory algorithm by developing 3D ski model using computer simulation and comparing with actual skiing data.

• Journal of Life Science
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• v.20 no.4
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• pp.543-548
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• 2010

The purpose of this study was to examine the differences in kinetics between 6 months of rehabilitation training and 12 months of rehabilitation training after total hip arthroplasty. 10 unilateral THA participants performed kinetic tests. Three dimensional kinematics and hip flexors and abductors electromyography (EMG) were collected during each trial. T-test was used for statistical analysis (p<0.05). There was no significant difference in EMG data between the two groups, but the mean comparison EMG data was higher in the 12 months rehabilitation training group than the 6 months rehabilitation training group. The moment value was found with motion-dependent interaction analyzing method which was used by Feltner and Dapena. There was no significant difference between moment values of the two groups. There was no significant difference between ground reaction forces of the two groups; however, there were some differences shown in Fz (vertical reaction force) between the two groups ($892{\pm}104\;N$, $820{\pm}87\;N$). The first peak impact force was about 9% lower in the 12 months group compared to the 6 months group. The second peak active force was nearly equal between the two groups. More research is necessary to determine exactly what constitutes optimal rehabilitation training biomechanics for patients with total hip arthroplasty.

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.47-61
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• 2004

Although the purpose of orthodontic treatment is to increase the function and esthetics of the jaws along with increasing stability, there are many side effects during the treatment itself, such as root resorption and alveolar bone resorption. Such resorption of the apical root Is unpredictable, and may even proceed into the dentin layer. Once the process has begun, it is irreversible. By evaluating the effect of many oral habits, especially that of nail biting, in correlation with the root and the periodontal tissues, the appropriate biomechanics for orthodontic treatment can be taken into consideration, along with the possibility of root resorption and alveolar bone loss during orthodontic treatment, and any legal problems that might occur. Among the male and female patients of the ages $10\~15$ without skeletal deformity, 63 were chosen as the experiment group with known nail biting habits at time of examination, and within the same age group without nail biting habits as the control. After the orthodontic treatment, number of the experiment group was 31 and the control group was 22. The periapical radiographies of anterior teeth were taken and the assesment of the root length and alveolar bone level were taken before(T1) and after(T2) the orthodontic treatment. The results from this study were as follows : 1. Before the orthodontic treatment, average crown-to-root ratio of the experimental group showed noticeably high values in 4 maxillary incisors and mandibular right central incisor. 2. Before the orthodontic treatment, comparing the root length, maxillary and mandibular right central incisors and both mandibular incisors had a smaller value in the experimental group. 3. Before the orthodontic treatment, comparing and evaluating the alveolar bone loss measured from the cemento-enamel junction to the alveolar bone crest, some crestal bone of the experiment group showed greater loss than the control. 4. After the orthodontic treatment, there was shortening of the root length and loss of the crestal bone in both groups. 5. After the orthodontic treatment, the changes of C/R ratio and the shortening of root length were significantly high in the experimental group. 6. After the orthodontic treatment, the level of alveolar crestal bone showed greater loss in the experimental group.

• The korean journal of orthodontics
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• v.26 no.4
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• pp.389-399
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• 1996

Remineralization of acid-etched enamel across the time has been one of the curiosities in the context of the orthodontic biomechanics(Arends J. et al., IRL Press, 1, 1985), nevertheless, is so far controversial. It was the aim of this study to observe the remineralization patterns of acid-etched enamel across the time and whether the existence of fluoride might carry out any modifications. The intact buccal surfaces of the first bicuspids which was extracted for orthodontic treatment were ground smooth, and etched with a 38w/w% phosphoric acid for 60 seconds, The surface was observed by the scanning electron microscope and surface microhardness was measured after immersion in the fluoride or non-fluoride containing remineralizing solution for 0 hour, 12 hours, 1 day, 3 days, 7 days, 14 days, 28 days, and 42 days. The following results and conclusions were drawn; 1. Surface microhardness increased in both fluoride containing and non-fluoride containing solution group with time lapse. 2. In fluoride containing solution group, the surface microhardness sharply increased at the 12 hours group, on the other hand, surface microhardness increased at 3 days in non-fluoride containing solution group. 3. The difference in microhardness value between two groups manifested gradual decrease. 4. Scanning electron microphotographs disclosed that the fluoride containing solution group generated spiculate sub-stances in the 12 hours group, which was increased in number and size with time lapse. 7 days later, spherical composure was began to be produced, The spiculate substances so much increased in number that the etched enamel surface looked like flat in 42 days. 5. In non fluoride-containing solution group, there was no surface change at 42 days, perceivable in scanning electron microphotographs which could be defined as remineralization though the surface was a little rougher than the incipient etched surface. These results demonstrate that the action of the fluoride is exceedingly pertinent in the remineralization of acid-etched enamel and the remineralization process goes uninterruptedly with time lapse.

• Journal of Biomedical Engineering Research
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• v.25 no.3
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• pp.171-182
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• 2004

This study investigates the biomechanical efficacies of vertebroplasty which is used to treat vertebral body fracture with bone cement augmentation for osteoporotic patients using image and finite element analysis. Simulated models were divided into two groups: (a) a vertebral body, (b) a functional spinal unit(FSU). For a vertebral body model, the maximum axial displacement was investigated under axial compression to evaluate the effect of structural integrity. The stiffness of each FE model simulated was normalized by the stiffness of intact model. In the case of FSU model, 3 types of compression fractures were formulated to assess the influence on spinal curvature changes. The FSU models were loaded under compressive pressure to calculate the change of spinal curvature. The results according to the various factors suggest that vertebroplasty has the biomechanical efficacy of the increment of structural reinforcement in a patient who has relatively high level of BMD and a patient with the amount of 15％, PMMA injection of the cancellous bone volume. The spinal curvatures after compression fracture simulation vary from 9$^{\circ}$ to 17$^{\circ}$ of kyphosis compared to that the spinal curvature of normal model was -2.8$^{\circ}$ of lordosis. These spinal curvature changes cause the severe spinal deformity under the same loading. As the degree of compressive fracture increases the spinal deformity also increases. The results indicate that vertebroplasty has the increasing effect of the structural integrity regardless of the amount of PMMA or BMD and the restoration of decreased vertebral body height may be an important factor when the compressive fracture caused the significant height loss of vertebral body.

• The korean journal of orthodontics
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• v.29 no.6 s.77
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• pp.689-698
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• 1999

Although the purpose of orthodontic treatment is to increase the function and aesthetics of the jaws as well as to increase stability, there are side effects from the treatment itself such as root resorption and alveolar bone resorption. Such resoiption of the apical root is unpredictable and may even proceed into the dentin layer. Once the process has begun, it is irreversible. By evaluating the effects of different oral habits, especially that ef nail biting, and their correlation with the root and the periodontal tissues, the appropriate biomechanics for orthodontic treatment can be taken into consideration. The possibility of root resorption and alveolar bone loss during orthodontic treatment can also be considered. Also, any legal problems that might occur may be pondered as well. Among the male md female patients of the ages 10~15, 63 were chosen as the test group with known nail biting habits at time of examination and within the same age range those without nail biting habits as the control group. The test group was composed of 30 males and 33 females. The control group had 31 males and 32 females. The result from this study were as follows : 1. Of the 63 patients of both the test and control groups, the male-to-female-ratio was 1:1, and had no statistically significant difference in male and female root resorption. 2. In comparing crown length of the test and control groups, no significant difference existed, but in root length, maxillary and mandibular right and left central incisors and mandibular right lateral incisors had a smaller value. (p<0.001) 3. Average crown-to-root ratio of the test group on the periapical view show a noticeably high value for the maxillary and mandibular right and left central incisors and mandibular right and left lateral incisors. (p<0.01) 4. In comparing and evaluating the alveolar bone loss measured from the cemento-enamel junction to the alveolar bone crest, mesial surfaces of the maxillary and mandibular right and left central incisors and distal surface of maxillary right central incisor of the test group showed greater loss of crestal bone than the control. (p<0.05)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.2
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• pp.166-179
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• 2008

Excessive concentration of stress which is occurred in occlusion around the implant in case of the implant supported fixed partial denture has been known to be the main cause of the crestal bone destruction. Therefore, it is essential to evaluate the stress analysis on supporting tissue to get higher success rates of implant. The purpose of this study was to evaluate the effects of stress distribution and deformation in 3 different types of three-unit fixed partial denture sup-ported by two implants, using a three dimensional finite element analysis in a three dimensional model of a whole mandible. A mechanical model of an edentulous mandible was generated from 3D scan, assuming two implants were placed in the left premolars area. According to the position of pontic, the experiments groups were divided into three types. Type I had a pontic in the middle position between two implants, type II in the anterior posi-tion, and type III in the posterior position. A 100-N axial load was applied to sites such as the central fossa of anterior and posterior implant abutment, central fossa of pontic, the connector of pontic or the connector between two implants, the mandibular boundary conditions were modeled considering the real geometry of its four-masticatory muscular supporting system. The results obtained from this study were as follows; 1. The mandible deformed in a way that the condyles converged medially in all types under muscular actions. In comparison with types, the deformations in the type II and type III were greater by 2-2.5 times than in the type I regardless of the loading location. 2. The values of von Mises stresses in cortical and cancellous bone were relatively stable in all types, but slightly increased as the loading position was changed more posteriorly. 3. In comparison with type I, the values of von Mises stress in the implant increased by 73% in Type II and by 77% in Type III when the load was applied anterior and posterior respectively, but when the load was applied to the middle, the values were similar in all types. 4. When the load was applied to the centric fossa of pontic, the values of von Mises stress were nearly $30{\sim}35%$ higher in the type III than type I or II in the cortical and cancellous bone. Also, in the implant, the values of von Mises stress of the type II or III were $160{\sim}170%$ higher than in the type I. 5. When the load was applied to the centric fossa of implant abutment, the values of von Mises stress in the cortical and cancellous bone were relatively $20{\sim}25%$ higher in the type III than in the other types, but in the implant they were 40-45% higher in the type I or II than in the type III. According to the results of this study, musculature modeling is important to the finite element analysis for stress distribution and deformation as the muscular action causes stress concentration. And the type I model is the most stable from a view of biomechanics. Type II is also a clinically accept-able design when the implant is stiff sufficiently and mandibular deformation is considered. Considering the high values of von Mises stress in the cortical bone, type III is not thought as an useful design.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.401-410
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• 2003

This study investigates the biomechanical efficacies of various cement augmentation techniques with or without pressurization for varying degrees of osteoporotic femur. For this study, a biomechanical analysis using a finite element method (FEM) was undertaken to evaluate surgical procedures, Simulated models include the non-cemented(i.e., hip screw only, Type I), the cement-augmented(Type II), and the cemented augmented with pressurization(Type III) models. To simulate the fracture plane and other interfacial regions, 3-D contact elements were used with appropriate friction coefficients. Material properties of the cancellous bone were varied to accommodate varying degrees of osteoporosis(Singh indices, II∼V). For each model. the following items were analyzed to investigate the effect surgical procedures in relation to osteoporosis of varying degrees : (a) von Mises stress distribution within the femoral head in terms of volumetric percentages. (b) Peak von Mises stress(PVMS) within the femoral head and the surgical constructs. (c) Maximum von Mises strain(MVMS) within the femoral head, (d) micromotions at the fracture plane and at the interfacial region between surgical construct and surrounding bone. Type III showed the lowest PVMS and MVMS at the cancellous bone near the bone-construct interface regardless of bone densities. an indication of its least likelihood of construct loosening due to failure of the host bone. Particularly, its efficacy was more prominent when the bone density level was low. Micromotions at the interfacial surgical construct was lowest in Type III. followed by Type I and Type II. They were about 15-20% of other types. which suggested that pressurization was most effective in limiting the interfacial motion. Our results demonstrated the cement augmentation with hip screw could be more effective when used with pressurization technique for the treatment of intertrochanteric fractures. For patients with low bone density. its effectiveness can be more pronounced in limiting construct loosening and promoting bone union.