• The Journal of Korean Physical Therapy
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• 제15권3호
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• pp.173-188
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• 2003

The two groups each consisting of 28 people who had an adult hemiplegia due to a brain injury received two different methods of exercises to reduce the angle to which the affected lower limb rotates externally. The comparisons between the two groups were made for the changes of the angle in external rotations measured between pre and post test. The static balance index values taken during pre and post tests were also compared. In addition, the correlations of the angle to which the affected lower limb rotates externally with static balance index values were analyzed. The result were as follows: 1. A statistical analysis indicated that in group one having taken simple R.O.M exercises, the angle to which the affected lower limb rotates externally and the static balance index values were both significantly different between pre and post test (P<.01). 2. A statistical analysis indicated that in group two having taken a pattern movement, both the angle to which the affected lower limb rotates externally and static balance index values were significantly different between pre and post test (P<.01). 3. A significant difference between simple R.O.M exercises group and pattern movement exercises groupwas shown only for the angle to which affected limb rotates externally not for static balance index values (P<.01), 4. Pearson correlation coefficient for the angle to which the affected limb rotates externally with static balance index values was found to be significant only in pattern movement exercises group (P < .05).

• Advances in biomechanics and applications
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• 제1권3호
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• pp.169-185
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• 2014

Computational multibody models of the elbow can provide a versatile tool to study joint mechanics, cartilage loading, ligament function and the effects of joint trauma and orthopaedic repair. An efficiently developed computational model can assist surgeons and other investigators in the design and evaluation of treatments for elbow injuries, and contribute to improvements in patient care. The purpose of this study was to develop an anatomically correct elbow joint model and validate the model against experimental data. The elbow model was constrained by multiple bundles of non-linear ligaments, three-dimensional deformable contacts between articulating geometries, and applied external loads. The developed anatomical computational models of the joint can then be incorporated into neuro-musculoskeletal models within a multibody framework. In the approach presented here, volume images of two cadaver elbows were generated by computed tomography (CT) and one elbow by magnetic resonance imaging (MRI) to construct the three-dimensional bone geometries for the model. The ligaments and triceps tendon were represented with non-linear spring-damper elements as a function of stiffness, ligament length and ligament zero-load length. Articular cartilage was represented as uniform thickness solids that allowed prediction of compliant contact forces. As a final step, the subject specific model was validated by comparing predicted kinematics and triceps tendon forces to experimentally obtained data of the identically loaded cadaver elbow. The maximum root mean square (RMS) error between the predicted and measured kinematics during the complete testing cycle was 4.9 mm medial-lateral translational of the radius relative to the humerus (for Specimen 2 in this study) and 5.30 internal-external rotation of the radius relative to the humerus (for Specimen 3 in this study). The maximum RMS error for triceps tendon force was 7.6 N (for Specimen 3).

• 대한전기학회논문지:전력기술부문A
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• 제52권6호
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• pp.307-315
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• 2003

This paper proposes a novel simulation method of WPGS (Wind Power Generation System). The rotation speed control method of turbine under variable wind speed using the pitch control is proposed. Moreover, when wind speed exceeds the cut-out wind speed, the turbine will be stopped by controlling pitch angle to 90$^{\circ}$, otherwise it will be controlled to steady-state operation. For the purpose of effective simulation, the SWRW (Simulation method for WPGS using Real Weather condition) is used for the utility interactive WPGS simulation in this paper, in which those of three topics for the WPGS simulation: user-friendly method, applicability to grid-connection and the utilization of the real weather conditions, are satisfied. It is impossible to consider the real weather conditions in the WPGS simulation using the EMTP type of simulators and PSPICE, etc. External parameter of the real weather conditions is necessary to ensure the simulation accuracy. The simulation of the WPGS using the real weather conditions including components modeling of wind turbine system is achieved by introducing the interface method of a non-linear external parameter and FORTRAN using PSCAD/EMTDC in this paper. The simulation of long-term, short-term, over cut-out and under cut-out wind speeds will be peformed by the proposed simulation method effectively. The efficiency of wind power generator, power converter and flow of energy are analyzed by wind speed of the long-term simulation. The generator output and current supplied into utility can be obtained by the short-term simulation. Finally, transient-state of the WPGS can be analyzed by the simulation results of over cut-out and under cut-out wind speeds, respectively.

• 한국기계가공학회지
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• 제11권3호
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• pp.138-145
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• 2012

The material used in this study is dielectric and ferrite. Because of the unique characteristics of the material, it is easily exposed to external shocks and pressure, which cause damage to the product. However, after being processed under high-temperature environment repeatedly, the mechanical strength of the product is greatly increased due to the change of the electrical properties. In this paper, dielectric and bonded ferrite material was tested for the material properties. The equipment for this experiment was produced and tested to allow Cylindrical and Three-dimensional geometry of the product for the vacuum deposition. For Cylindrical shape of the product, in order to obtain the equivalent film thickness, the device is constructed in a vacuum chamber which gives arbitrary revolving and rotating capability. The electrical performance of the product is obtained through this process as well. However, as mentioned above, with repeating processes under high temperature and exposure to external environment, the product is easy to be broken. This experiment has enabled us to find out a stable condition to apply the communication of the RF high frequency to each of the core elements, such as Ferrite and Dielectric which is then used for the mechanical strength of the Raw material, hetero-junction material, Hetero-junction Ag Coating material and hetero-junction Ag Coating SiO2 Coating material respectively.

• 대한조선학회논문집
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• 제50권3호
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• pp.175-181
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• 2013

This paper presents a simulation for passenger ship evacuation considering the inclination of a ship. In order to describe a passenger's behavior in an evacuation situation, a passenger is modeled as a rigid body which translates in the horizontal plane and rotates along the vertical axis. The position and rotation angle of a passenger are calculated by solving the dynamic equations of motions at each time step. To calculate inclined angle of damaged ship, static equilibrium equations of damaged ship are derived using "added weight method". Using these equations, physical external forces due to the inclination of a ship act on the body of each passenger. The crowd behavior of the passenger is considered as the flock behavior, a form of collective behavior of a large number of interacting passengers with a common group objective. Passengers can also avoid an obstacle due to penalty forces acting on their body. With the passenger model and forces acting on its body, the test problems in International Maritime Organization, Maritime Safety Committee/Circulation 1238(IMO MSC/Circ.1238) are implemented and the effects of ship's inclination on the evacuation time are confirmed.

• 한국항행학회논문지
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• 제22권5호
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• pp.351-358
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• 2018

본 연구에서는 개발된 모터 조립체의 누설 잡음신호 감쇠 방안을 시험을 통해 제안한다. 개발된 장치는 항공기 외부에 장착되어 안테나를 회전시키기 위한 장치로서 전자기 간섭 측면에서 MIL-STD-461F의 RE102 요구규격을 충족해야한다. RE102 시험결과를 통해 장치의 누설 잡음신호가 전원 및 제어 케이블을 통한 외부 유입과 모터 회전에 의해 발생됨을 확인하였다. 그리고 회전을 위해 내 외부의 물리적 차폐가 어려운 부분에서 잡음신호가 누설됨을 확인하였다. 누설 잡음신호에 대한 감쇠를 위해 장치 동작을 고려한 전기적 접지 보강, 전기적 차폐 구조를 적용하여 시험을 수행했고 규격 충족 여부를 확인하였다. 최종적으로 잡음누설 경로에 맞물리는 형태를 갖는 원형 주름 초크 구조와 전도성 그리스를 함께 적용하여 요구규격을 충족함을 확인하였다.

• Clinics in Shoulder and Elbow
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• 제8권1호
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• pp.23-30
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• 2005

Purpose: This paper analyzes the results of arthroscopic bankart repair for anterior recurrent dislocation following a trauma on shoulder. Material and Methods: The subjects were twenty-three (23) cases that were available to follow up for more than eighteen months during the period from November 2001 to June 2003 and were chosen from patients to whom arthroscopic bankart repair was applied using a knotless suture anchor for their traumatic anterior recurrent dislocation on the shoulder. Their average age was 28 (ranging from 15 to 60) with 20 males and 3 females. The injury from sports activities accounted for the most cases with 14 subjects. The average follow-up period was 27 months (ranging from 18 months to 35 months). There were 19 cases of bankart lesions, 4 cases of ALPSA lesions and associated with 5 cases of partial tear in the rotator cuff. The anchors employed were knotless anchor (Mitek) for all the cases. Rowe scoring scale was adopted to judge the results after operations. Patients' subjective satisfaction and range of motion of external rotation were addressed together. Results: Rowe scores showed that 20 cases (87%) reaches the level of 'good' and hinger. The average patients' satisfaction accounted for 90 points out of 100. It was also found that external rotations averagely decreased by 6.5 degree when the range of motion was in at the side. Conclusion: There were satisfactory results of arthroscopic bankart repair using knotless suture anchors as an operative treatment for traumatic anterior recurrent dislocation on shoulder.

• 한국운동역학회지
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• 제15권3호
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• pp.9-19
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• 2005

The purpose of this study was to analyze the effects of three different types of preparatory movement(squat, countermovement and hopping) in sideward responsive propulsion movement. 7 healthy subjects performed left and right side movement task by external output signal. 3D kinematics were analyzed The results were followed First, performance time in the countermovement and hopping conditions was shorter(10-20%) than that in the squat condition. The hopping condition that is more related to pre-stretch showed excellent performance. Second, time difference between after turned on the external signal and until take off was the primary factor in performance results among movement conditions. The preparatory phase before the propulsive phase in the squat condition produced more time than that in other conditions. The hopping condition showed the most short time in both the preparatory and the propulsive phase, therefore it was advantage for performance result Third, significant difference was not found in take-off velocity among movement conditions although there was difference of the time required in the propulsive phase. The maximum acceleration in the propulsive phase was larger in order of the hopping. countermovement, and squat condition. The countermovement and hopping conditions showed high take-off velocity although the propulsive phase in those conditions was shorter than that in squat condition. The pre-stretch by preparatory countermovement was considered as the positive factor of producing power in concentric contraction. Fourth, the hopping condition produced large angular velocity of joints. In hopping condition, large amount of moment for rotation movement was revealed in relatively short time and it was considered to cause powerful joint movements. In conclusion, the hopping movement using countermovement is advantage of responsive propulsion movement. It is resulted from short duration until take off and large amount of joint moment and joint power in concentric contraction by pre-stretch.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.244-250
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• 2021

Objective: The purpose of this study was to investigate the effect of sprinter pattern bridging exercise using theraband on activation of lower extremity and abdominal muscle and to find out postures that can effectively improve abdominal and lower extremity muscle strength and increase abdominal stability. Methods: This study was designed as a cross-sectional study. The following research was done with applicants attending S university in Seoul to compare the difference in muscle activity between one-leg-Support bridging exercise and sprinter-pattern bridging exercise using theraband. For 48 study participants, we first measured their MVC. Then, we applied one-leg-support bridging exercise and sprinter-pattern bridging exercise at random order. These data were expressed as the percentage of maximal voluntary contraction (%MVC).Electromyography analysis was performed by measuring the external obliques, internal obliques, biceps femoris, and gluteus maximus. Results: There was a statistically significant increment of muscle activity in external and internal oblique muscle(p<0.001)by sprinter-pattern bridging exercise using theraband. On the lower body, statistically significant increment of muscle activity in biceps femoris and gluteus maximus was found(p<0.05). On the other hand, on erector spinae, there was statistically significant decrease in muscle activity(p<0.05). Conclusions: Efficient treatment is expected when sprinter-pattern bridging exercise using theraband is applied clinically.For patients with chronic knee and ankle pain who have difficulty bearing weight, including low back pain and internal rotation of the femur, starting with a low weight bearing, we think it will be helpful in planning systematic training aimed at progressively strengthening the lower extremities.

• 한국해양공학회지
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• 제35권6호
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• pp.434-445
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• 2021

This paper proposes an optimal design method for an unmanned underwater vehicle (UUV) platform to overcome strong current. First, to minimize the hydrodynamic drag components in water, the vehicle is designed to have a streamlined disc shape, which help maintaining horizontal motion (zero roll and pitch angles posture) while overcoming external current. To this end, four vertical thrusters are symmetrically mounted outside of the platform to stabilize the vehicle's horizontal motion. In the horizontal plane, four horizontal thrusters are symmetrically mounted outside of the disc, and each of them has the same forward and reverse thrust performances. With these four thrusters, a specific thrust vector control (TVC) method is proposed, and for external current in any direction, four horizontal thrusters are controlled to generate a vectored thrust force to encounter the current while minimizing the vehicle's rotation and maintaining its heading. However, for the numerical simulations, the vehicle's hydrodynamic coefficients related to the horizontal plane are derived based on both theoretical and empirically derived formulas. In addition to the simulation, experimental studies in both the water tank and circulating water channel are performed to verify the vehicle's various final performances, including its ability to overcome strong current.