• 대한통합의학회지
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• 제12권3호
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• pp.155-161
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• 2024

Purpose : Wearing high-heeled shoes leads to foot and ankle instability, which requires leg muscles to remain in constant contraction. In order to adapt to the instability of the feet and ankles caused by wearing high heels, the muscles of the legs continuously repeat contraction and relaxation. Previous studies of the impact of stair climbing in high-heeled shoes have involved placing the entire stepping area of the shoe on the stair. However, high-heeled shoe wearers sometimes unconsciously contact the stair using only half of the stepping area. Therefore, the objective of this study was to examine differences in leg and ankle muscle activation according to stepping area during stair climbing in high-heeled shoes. Methods : Twenty young women in their early 20s voluntarily agreed to participate in this study. We used surface electromyography to measure gastrocnemius and tibialis anterior activation in the right leg during stair climbing under three conditions: barefoot, using half of high-heeled shoe stepping area, and using the total of high-heeled shoe stepping area. Barefoot, half of high heeled shoe, and total of high-heeled shoe were used to evaluate the effects of different areas of the foot or high heels touching the stairs. Results : Both muscles showed significant activity differences among the three stair climbing conditions. Gastrocnemius activity was significantly different between the high-heeled shoe conditions (p= .032), and tibialis anterior activity was significantly different between barefoot stair climbing and climbing with half of the high-heeled shoe stepping area (p= .021). Conclusion : The stepping area increased as heel size increased, thus increasing excessive gastrocnemius and tibialis anterior activity to control excessive ankle joint movement. We infer that using half of the high-heeled shoe stepping area prevents muscle fatigue by reducing excessive leg and ankle muscle activation.

• 한국공작기계학회논문집
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• 제16권5호
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• pp.48-54
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• 2007

Surface of rapid prototype has inevitably stair-stepping error, which is attributed to the continuous building process of 2 dimensional area. In this study, rounded edge model was established to estimate the roughness of inclined surface which has stair-stepping error. To investigate the roughness of rapid prototypes, specimens that have various surface inclinations were manufactured by various types of RP machines. As the surface inclination increased, the roughness of the specimens manufactured by SL, FDM, or LOM process decreased, which coincides with the simulation results. However, surface roughness of 3DP specimen was almost independent of the inclination. Furthermore, as the angle of surface increased, roughness of poly-jet specimen also increased, which is attributed to the frictional behavior between writing head and scanned area.

• 근관절건강학회지
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• 제18권2호
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• pp.249-256
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• 2011

Purpose: The purpose of this study was to investigate electromyographic(EMG) activity of vastus medialis oblique(VMO) and vastus lateralis(VL) following the application of patellar taping during stair stepping. Methods: Both VMO-VL onset timing and VMO/VL ratio of 15 participants with patellofemoral pain syndrome (PFPS) were measured using an surface EMG uint(Myosystem 1400A, Noraxon Inc., USA). The measurements were taken under three conditions in random order of patellar taping, placebo taping, and no-taping. Data were analysed using $1{\times}3$ repeated measures ANOVA. Results: There was a significant difference with patellar taping on VMO/VL amplitude compared with the placebo taping and no-taping conditions during stair stepping, but no significant difference on VMO-VL onset timing. Conclusion: These result indicate that patellar taping on the vastus medialis oblique has effect on the VMO/VL ratio. Increased values of VMO/VL ratio may contribute to patellar realignment and explain the mechanism of pain reduction following patellar taping in participants with PFPS.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.45-48
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• 2001

SL(Stereolithogrphy) part is made by piling up thin layers which causes the stair stepping effect at the surface of SL parts. This effect causes excessive surface roughness and requires additional postprocess finishing such as abrasive basting which is detrimental to part geometry and time consuming. Hence paraffin coating and grinding postprocess is proposed to raise the surface quality of SL part. The paraffin which has suitable properties for the proposed postprocess is coated all over the part surface. By grinding the thin layer of coated on the SL part only, the surface roughness can be improved without any damage on the part. From the experimental result, It is verified as very practical for die casting with silicon rubber mold.

• International journal of advanced smart convergence
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• 제9권4호
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• pp.26-33
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• 2020

This study measured the downward stepping movement relative to weight change (no load, and 10%, 20%, 30% of body weight respectively of adult male (n=10) from standardized stair (rise of 0.3 m, tread of 0.29 m, width of 1 m). The 3-dimensional cinematography and ground reaction force were also utilized for analysis of leg stiffness: Peak vertical force, change in stance phase leg length, Torque of whole body, kinematic variables. The strategy heightened the leg stiffness and standardized vertical ground reaction force relative to the added weights (p<.01). Torque showed rather larger rotational force in case of no load, but less in 10% of body weight (p<.05). Similarly angle of hip joint showed most extended in no-load, but most flexed in 10% of body weight (p<.05). Inclined angle of body trunk showed largest range in posterior direction in no-load, but in vertical line nearly relative to added weights (p<.001). Thus the result of the study proved that downward stepping strategy altered from height of 30 cm, regardless of added weight, did not affect velocity and length of lower leg. But added weight contributed to more vertical impulse force and increase of rigidity of whole body than forward rotational torque under condition of altered stepping strategy. In future study, the experimental on effect of weight change and alteration of downward stepping strategy using ankle joint may provide helpful information for development of enhanced program of prevention and rehabilitation on motor performance and injury.

• 한국의류산업학회지
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• 제2권5호
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• pp.430-436
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• 2000

The purpose of the study was to obtain the basic data on the self-adjusting ability of the support panty stockings. Ten healthy women in the twenties were selected as subjects and clothing pressure of 9 support panty stockings made of single covered yarn (SCY) and double covered yarn (DCY) were measured under the standard environmental condition for the study. Data was analysed statistically according to body postures, sides, and parks. The results were as follows: Clothing pressure according to body posture was order of 'sitting-on-a-chair', 'stepping-up-a-stair', and 'standing'. High clothing pressure was obtained in the parts of calf ($9.4gf/cm^2$) in 'standing' and knee (9.7 and $16.5gf/cm^2$) in both 'stepping-up-a-stair' and 'sitting-on-a-chair', respectively. The order of clothing pressure with body sides was 'front', 'side', and 'back'. The highest clothing pressure was knee ($18.8gf/cm^2$) on the front, thigh ($8.8gf/cm^2$) on the side, and calf ($6.4gf/cm^2$) on the back. Clothing pressure of DCY at abdomen and knee was a little higher than those of SCY 3. In terms of material structure variation, clothing pressure of thigh, calf and ankle with SCY was a little higher than those with DCY, while clothing pressure of abdomen and knee with DCY was a little higher than those with SCY.

• 제어로봇시스템학회논문지
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• 제19권7호
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• pp.640-645
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• 2013

This paper presents a step length estimation algorithm for Pedestrian Dead Reckoning using linear calibrated ZUPT (zero velocity update) with a foot mounted IMU. The IMU consists of 3 axis accelerometer, gyro and magnetometer. Attitude of IMU is estimated using an inertial navigation algorithm. To increase accuracy of step length estimation algorithm, we propose a stance detection algorithm and an enhanced ZUPT. The enhanced ZUPT calculates firefighter's step length considering velocity error caused by sensor bias during one step. This algorithm also works efficiently at various motions, such as crawling, sideways and stair stepping. Through experiments, the step length estimation performance of the proposed algorithm is verified.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.659-662
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• 2002

SL(Stereolithography) part is made by piling up thin layers which causes the stair stepping effect at the surface of SL parts. This effect brings about excessive surface roughness and requires additional post-process finishing such as abrasive techniques that are detrimental to part geometry and time consuming. Hence a wax coating and grinding post-process is proposed to improve the surface quality of SL part. The wax that has suitable properties for the proposed post-process is coated all over the part surface. By grinding the thin layer of coated on the SL part only, the surface roughness can be improved without any damage on the part. From the experimental results, This approach is considered to be very practical fur die casting with RT(Rapid Tooling) techniques.

• 한국정밀공학회지
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• 제21권9호
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• pp.196-203
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• 2004

SL(Stereolithography) part is made by piling up thin layers which causes the stair stepping effect at the surface of SL parts. The effect brings about excessive surface roughness and cuts down the merits of using SL part. Hence, additional post-machining finishing such as traditional grinding is required. But the traditional post-machining is detrimental to part geometry and time consuming. In this study, therefore, a paraffin coating and grinding post-machining is newly proposed to improve the surface quality of SL fart. The paraffin which has suitable properties for the proposed post-machining is coated all over the part surface. By grinding the only over-coated paraffin based on boundary of the SL part surface, the surface roughness can be improved without any damage on the part. Also, it is verified that SL part finished by the proposed post-machining process can be applied for rapid tooling as pattern through manufacturing silicon rubber molding and casting test.

• 대한기계학회논문집A
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• 제26권11호
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• pp.2409-2414
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• 2002

The surfaces of prototypes become rough due to the stair-stepping which is the inevitable phenomenon in the Rapid Prototypes are not used only for the verification of feature. The grinding, coating, or the composition of them is a main operation in post-processing in which lots of costs and long build time are needed. The solution is proposed to increase the efficiency of rapid prototyping by minimizing or removing the composition of them is a main operation in post-processing in which lots of costs and long build time are needed. the solution is proposed to increase the efficiency of rapid prototyping by minimizing or removing the regions for post-processing. the factors to cause the surface roughness and their effects are analyzed through the experiments. Software modules are developed to predict the surface roughness of each face in the prototyping with the result. An experimental compensation method is developed to apply the modules to various RP equipments, materials and build styles. The build direction is searched with use of genetic algorithm to maximize the total areas of the surface of which roughness is better than the user-defined value.