• Clinics in Shoulder and Elbow
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• v.1 no.2
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• pp.205-211
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• 1998

The comminuted fracture and dislocation of the proximal humerus occur more frequently in older patient group and operative treatment is difficult due to poor bone quality. Based on Neer's work, hemiarthroplasty has now become widly accepted for the management of the three-part fracture and four-part fracture-dislocation of the proximal humerus in old age group. The purpose of this study is to evaluate function, pain relief, and patient satisfaction after hemiarthroplasty for proximal humerus fractures and dislocations. Authors reviewed and analyzed 14 prosthetic replacement in comminuted proximal humeral fracture and dislocation at the Department of Orthopaedic Surgery, Yonsei University Wonju College of Medicine from March, 1988 to May, 1997. The results were as follows the average age was 58.9years and the ratio of males and females was 5:9. The most common cause of injury was traffic accident(43%). According to the classification of Neer, three part fracture were three(21%), four-part fracture and four-part fracture-dislocation were eleven(79%). The prosthetic replacement was performed within two weeks in eight patient and six were performed after two weeks. The results were analysed according to Neer's criteria and five cases showed satisfactory results. We concluded that hemiarthroplasty for fracture and dislocation of the proximal humerus facilitated the restoration of humerus length and pain relief, thereby allowing earlier motion to prevent the development of painful shoulder: stiffness.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.105-110
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• 2011

Purpose: The purpose of this article is to identify and understand the complications of RTSA and to review the current methods of preventing and treating this malady. Materials and Methods: Previous constrained prostheses (ball-and-socket or reverse ball-and-socket designs) have failed because their center of rotation remained lateral to the scapula, which has limited of the motion of the prostheses and produced excessive torque on the glenoid component, and this leads to early loosening. The Grammont reverse prosthesis imposes a new biomechanical environment for the deltoid muscle to act, thus allowing it to compensate for the deficient rotator cuff muscles. Results: The clinical experience does live up to the lofty biomechanical concept and expectations: the reverse prosthesis restores active elevation above $90^{\circ}$ in patients with a cuff-deficient shoulder. However, external rotation often remains limited and particularly in patients with an absent or fat-infiltrated teres minor. Internal rotation is also rarely restored after a reverse prosthesis. Failure to restore sufficient tension in the deltoid may result in prosthetic instability. Conclusion: Finally, surgeons must be aware that the results are less predictable and the complication/revision rates are higher in revision surgery than that in the first surgery. A standardized monitoring tool that has clear definitions and assessment instructions is surely needed to document and then prevent complications after revision surgery.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.435-448
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• 2009

The purpose of this study was to investigate the kinemaitc gait parameter of lower extremities with different gait conditions(level walking, stairs, ramp) in old adults. Fourteen healthy older adults participated in this study and kinematic data were measured using 3D motion analysis system(Vicon, Oxford Metrics, England). Statistical analysis was used one-way ANOVA to know the difference of lower extremities angle at each gait phase with a different gait conditions. In sagittal plane, pelvic anterior tilt increased in stairs and ramp climbing and hip and knee flexion increased in stairs climbing but ankle dorsiflexion increased in ramp climbing. In frontal plane, pelvic was up in stairs and hip abduction and adduction more changed in stairs climbing than level walking. Knee varus and ankle inversion increased in stair climbing. In horizontal plane, pelvic internal rotation increased in stairs and ramp climbing and knee internal rotation increased in stairs climbing but ankle external rotation increased in stairs climbing. This results was shown that the stairs and ramp climbing changed the kinematic gait parameters of lower extremities in healthy old adults.

• Journal of the Korean Society of Physical Medicine
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• v.1 no.1
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• pp.23-36
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• 2006

Purpose : The purpose of this study was to evaluate the effects of back muscle stretching on the flexibility of spinal column. Methods : The subjects were consisted of healthy adults (18 of females, 22 males ; mean aged 21.83) from 18 to 29. All subjects randomly assigned to the control group, back muscle stretching group. back muscle stretching group received back muscles stretching for 20 minutes per day and 3 times a week during 3 week period. Spine motion analyzer (Spinal Mouse) was used to measure the flexibility of spinal column. All measurement of each subjects were measured at pre-experiment, after 10 days, and after 21 days. Results : The results of this study were summarized below 1. The sacral tilt angle of the hip joint of control group, back muscle stretching group was no significantly differences at pre-experiment and after 10 days(p>0.5), but differency of each group occurred at after 21 days(p<0.5). the sacral tilt angle significantly increased at the back muscle stretching group rather than the control group. 2. The thoracic vertebral tilt angle of the control group, back muscle stretching group was no significantly differences at pre-experiment, after 10 days, after 21 days(p>0.5). 3. The lumbar vertebral tilt angle of the control group, back muscle stretching group was no significantly differences at pre-experiment, after 10 days, after 21 days(p>0.5). 4. The spinal tilt angle of control group, back muscle stretching group was no significantly differences at pre-experiment and after 10 days(p>0.5), but differency of each group occurred at after 21 days(p<0.5). the spinal tilt angle significantly increased at the back muscle stretching group rather than the control group(p>0.5). 5. The length of the spinal column of control group, back muscle stretching group was no significantly differences at pre-experiment and after 10 days (p>0.5), but differency of each group occurred at after 21 days(p<0.5). the length of the spinal column significantly increased at the back muscle stretching group rather than the control group(p<0.5). Conclusion : These data suggests that 3-week back muscle stretching improved the flexibility of sacrum, spinal column, and also improved spinal column lengthening. Additional randomized controlled trials to more fully investigate treatment effects and factors that may mediate these effects are needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5689-5697
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• 2013

The purpose of this study was to determine the effects of scapular taping on muscle activities of the scapular rotators and anterior deltoid, ROM, shoulder pain, proprioception in subacute stroke patients. Twenty-eight patients were randomly assigned to an experimental and control groups of fourteen patients respectively. Muscle activity of upper and lower trapezius, serratus anterior, anterior deltoid was measured using surface electromyography. Visual analog scale was used for shoulder pain. Electro-Goniometry was used for shoulder elevation ROM. Assessment board was used for shoulder elevation proprioception. The muscle activity of the lower trapezius and serratus anterior increased significantly after scapular tape application (p<0.05). The AROM and PROM in the shoulder elevation significantly increased after scapular tape application (p<0.05). The VAS in the shoulder no significantly decreased after scapular tape application (p>0.05). The proprioception in the shoulder no significantly increased after scapular tape application (p>0.05). The results of this study suggest that scapular taping can be used an additional therapy for increasing muscle activity of lower trapezius and serratus anterior and ROM during shoulder elevation in subacute stroke patients.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.779-791
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• 2009

The purpose of this study is to develop a program that computes the position of the instantaneous center of rotation while an object moves in a circular motion. For this study, a mathematical algorithm was developed and implemented on the experimental data. Data for pitching (40m carry) and putting (4m) strokes were obtained from a skilled female golfer. A computer program (Centering 1.0) calculated the experimental data and found the radius of the instantaneous center of rotation. When the data were taken broadly, the program produced an error distance of radius. When the data were divided gradually, the program produced a very close instantaneous center of rotation. On comparing pitching and putting strokes, putting was found to have a greater radius than pitching. The instantaneous centers of rotation of putting were not in the golfer's body rather, they were 3m away from the club head. The Centering 1.0 program can calculate the instantaneous center of rotation with at least three sets of experimental data.

• Journal of Korean Physical Therapy Science
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• v.10 no.1
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• pp.90-101
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• 2003

Gait analysis can provide a better understanding of how the alignment of the lower limb and foot can contribute to force observed at the knee. Anatomic and mechanical factors that affect loading in the knee pint can contribute to pathologic change seen at the knee in degenerative pint disease and should be considered in treatment plan. The purpose of this study is to present the gait analysis data and to determine whether there is any relationships between alignment of the lower limb, foot progression angle and knee pint moments in elderly healthy women with 3-dimensional motion analyzer. The results were as follows; 1. Cadence showed 114.8 steps/min, gait speed showed 1.05 m/s, time per a stride showed 1.06 sec, time per a step showed 0.53 sec, single-supporting phase was 0.41 sec, double-supporting phase was 0.24 sec, stride length was 1.04 m, Step length was 0.56 m. 2. According to the parameters of kinematics, the maximal knee flexion angle through swing phase showed left $46.82^{\circ}$, right $40.19^{\circ}$ and the maximal knee extension angle showed left $-1.32^{\circ}$, right $2.01^{\circ}$. knee varus showed left $26.90^{\circ}$, right $30.93^{\circ}$. 3. Moment, one of kinetic parameters of knee pint the maximal flexion moment showed left 0.363. Nm/kg, right 0.464 Nm/kg and maximal extension moment showed left 0.389 Nm/kg, right 0.463 Nm/kg. The maximal. adduction moment showed left 0.332 Nm/kg, right 0.379 Nm/kg and the maximal internal rotatory moment showed left 0.13 Nm/kg, right 0.140 Nm/kg. 4. On sagittal plane, the maximal power of knee joint showed left 0.571 J/kg, right 0.629 J/kg. On coronal plane, the maximal power of knee joint showed left 0.11 J/kg, right 0.12 J/kg. On transverse plane, the maximal power of knee joint showed left 0.058 J/kg, right 0.072 J/kg. 5. The subject who had varus alignment of the lower extremity had statistically higher in knee adduction moment in mid stance phase. 6. The subject who had large foot progression angle had statistically lower in knee adduction moment in late stance phase. A relationship was observed between the alignment of the lower extremity and the adduction moment of the knee joint during stance phase. Hence, we need some research to figure, out the change of adduction moment according to the sort of knee joint osteoarthritis and the normal geriatrics as well. And we also require more effective, specific therapeutic program by making use of those background of researches.

• Science of Emotion and Sensibility
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• v.9 no.2
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• pp.133-140
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• 2006

In order to investigate the sensation of the fabric sound simulating the real wear-condition, the fabric sound simulator using reciprocating friction was developed. Fabric sounds from 5 specimen were generated by the fabric sound simulator and recorded using high performance microphone. Physical sound parameters of fabrics including level pressure of total sound (LPT), level range (${\Delta}L$), and frequency differences (${\Delta}f$) were calculated. For psychological evaluation, seven adjectives for sound (softness, loudness, sharpness, clearness, roughness, highness, and pleasantness) were used as the semantic differential scale. Fabric sounds by reciprocating friction of nylon taffeta and polyester leno had the highest value of LPT and evaluated as loud, sharp, rough, and unpleasant while polyester ultra suede and silk crepe de chine haying the lower LPT and ${\Delta}f$ were perceived as soft and quite. Comparing with fabric sound by one-way friction, fabric sound by reciprocation friction was perceived as more sharp, loud, and rough. LPT was also the most important factor affecting the sensation of the fabric sound by reciprocating friction.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.9
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• pp.765-772
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• 2015

Aerodynamic force measurements and phase-locked PIV study were carried out to check the bio-mimetic MAV applicability of a swift flight. Two-rotational DOF robotic wing model and blowing-type wind tunnel were employed. The amplitude of twist angle were ${\pm}0$, ${\pm}5$, ${\pm}10$, and ${\pm}20$ deg. and stroke angles were manipulated by simple harmonic function with out-of-phase in regards to the stroke motion. It is acknowledged that the time-varying lift coefficients in accordance with the change of the twist angle did not result in any noticeable differences, just the small decrease and delay. However, the drag exhibited that the small change of the twist angle can produce large thrust. These findings imply why a swift uses small twist angle during flight. The PIV results displayed that the delay of aerodynamic forces is highly associated with the vortical structures around the wing. It is therefore indicated that a process of designing a swift-based Micro Air Vehicle should take the twist angle into consideration, as the essential parameter.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.304-311
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• 2014

In this study, to apply hydrogen energy to ship engine and to generate effective hydrogen production, we investigated the effects of high temperature $H_2SO_4$ feed rate and cooling water rate to pump parts with fixed frequency needed to reciprocate motion and a simulation was conducted at each condition. In the fixed frequency and cooling water inlet flow rate of 0.5 Hz and 3.9 kg/s, we changed the high temperature $H_2SO_4$ flow rate to 47.46 kg/s (it is 105 % of 45.2 kg/s), 49.72 kg/s (110 %), and 51.98 kg/s (115 %). Also, at 0.5 Hz and 45.2 kg/s of frequency and high temperature $H_2SO_4$ flow, the thermal hydraulic analysis was performed at the condition of 95 % (3.705 kg/s), 90 % (3.51 kg/s), and 85 % (3.315 kg/s). In overall simulation cases, the physical properties of materials are more influential to the temperature increase in the pump part rather than the changes on the feed rate of high temperature $H_2SO_4$ and cooling water. A continuous operation of pump was also capable even if the excess feed of high temperature $H_2SO_4$ of about 15 % or the less feed of cooling water of about 15 % were performed, respectively. When the increasing feed of high temperature $H_2SO_4$ of up to 5 %, 10 %, and 15 % were compared with base flow (45.2 kg/s), the deviation of time period rose to a certain temperature and ranged from 0 to 4.5 s in the same position (same material). In case of cooling water, the deviation of time period rose to a certain temperature and ranged from 0 to 5.9 s according to the decreasing feed changes of cooling water at 5 %, 10 %, and 15 % compared to a base flow (3.9 kg/s). Finally, the additional researches related to the two different materials (Teflon and STS for Pitch and End-plate), which are concerned about the effects of temperature changes to the parts contacting different materials, are needed, and we have a plan to conduct a follow-up study.