• Journal of Biomedical Engineering Research
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• 제30권3호
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• pp.241-246
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• 2009

Since inappropriate muscle forces mean that people cannot perform some activities related to roles of the muscle, muscle forces have been considered as an important parameter in clinic. Therefore, many methods have been introduced to estimate muscle forces indirectly. One of the methods is muscle tissue dynamics and it is widely used in commercial softwares including musculoskeletal model, such as SIMM. They, however, need motion data captured from 3-dimensional motion analysis system. In this study, we introduced an algorithm to estimate muscle forces in real-time by using joint angles. The heel-rise movements were performed for a normal with 3-dimensional motion analysis system, EMG measurement system, and electrogoniometers. Joint angles obtained from electrogoniometers and EMG signals were used to estimate muscle forces. Simulation was performed to find muscle forces using motion data which was imported into musculoskeletal software. As the results, muscle lengths and forces from the developed algorithm were similar to those from commercial software in pattern. Results of this study would be helpful to implement a tool to calculate reasonable muscle forces in real-time.

• Journal of Korean Institute of Industrial Engineers
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• 제26권3호
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• pp.257-264
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• 2000

This research suggested a method by which the driver space can be designed to best accommodate the driver's anthropometric characteristics. Three-dimensional manikins and a variable seating buck were developed and used for this study. Manikins were designed with 18 links comprising the 95th percentile male and 5th percentile female data. The seating buck was built to create various driving environments using the distance and the height between the H-point(hip pivot) of the seat and the AHP(accelerator heel point), the angle of the back rest, the angle of the steering wheel, the vertical distance of the steering wheel, and the location of the T.G.S.(transmission gear shift) knob. Measurements of each variable were collected with a coordinate measuring machine by positioning the 3-D manikin under various combinations of the design factors of the seating buck, which was constructed based on mid-size domestic passenger cars. The data were then converted to the joint angles of the driver. The combination of the measurements for an optimal driving environment is suggested by applying sets of the joint angles at which the driver feels comfortable.

• Journal of the Society of Naval Architects of Korea
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• 제58권4호
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• pp.253-261
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• 2021

This paper describes the process of evaluating maneuverability in still water of an unmanned surface vehicle based on data measured by performing sea trials. First, we set up a test scenario that is easy to analyze the maneuverability of the unmanned surface vehicle and to identify and verify the dynamics model. Since the attitude of hull varies according to the speed of the unmanned surface vehicle which has a planing hull shape, the relationship between waterjet RPM, speed and attitude is analyzed by performing straight forward tests at various speeds. The turning tests of the unmanned surface vehicle in which the waterjet angle rotates while turning are performed by changing the waterjet rotation angle under the condition of two representative speeds to analyze turning ability. The turning ability of the unmanned surface vehicle includes speed reduction, yaw rate, heel, and turing diameter at steady turning phase according to the speed and RPM.

• Physical Therapy Korea
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• 제11권2호
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• pp.27-34
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• 2004

The purpose of this study was to identify the influence of wedged insole and foot progression angle (FPG) on lateral thrust of knee in healthy subjects. Fifteen healthy male subjects were recruited from Suncheon First College, in Suncheon. The subjects randomly walked at the comfortable velocity under five conditions: bare footed, medio-lateral $10^{\circ}$ wedged insoles, toe-in and toe-out gait. The lateral thrust was measured by a accelerometer with telemeter during walking. Data was collected while each subject walked for about 10 gait cycle on a flat, level walkway at their normal speed. The middle three gait cycle were used for averaged peak value of lateral acceleration. The three averaged peak value of lateral acceleration were collected under each condition at heel strike. The results showed that averaged peak value of lateral acceleration increased significantly in medial wedged insole and toe-in gait and decreased significantly in lateral wedged insole and toe-out gait as compared with bare footed (p<.05). These results suggest that wedged insole as well as walking strategy, such as foot progression angle, may prevent progression of degenerative knee osteoarthritis.

• Journal of Korean Foot and Ankle Society
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• 제13권1호
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• pp.60-67
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• 2009

Purpose: This study was designed to investigate the usefulness of extensile lateral approach for accurate reduction and rigid internal fixation in comminuted intraarticular fractures of calcaneus. Materials and Methods: From October 2002 to May 2007, we managed 55 patients (62 cases) with open reduction and internal fixation using extensile lateral approach. Among these, 38 patients (43 cases) who underwent preoperative and postoperative CT scan were enrolled. All patients were evaluated over 24 months after surgery. Bohler angle and Gissane angle on plain X-ray, displacement and step-off of articular surface of calcaneus on CT scan were measured and we compared the difference between preoperative and postoperative value of them. Clinical results were assessed by using AOFAS Ankle-Hindfoot Scale. Results: The average Bohler angle was restored from $6.8^{\circ}$ to $23.5^{\circ}$ and Gissane angle was improved from $116.4^{\circ}$ to $113.5^{\circ}$ after operation. The average distance of displacement was restored from 4.2 mm to 1.4 mm and step-off of articular surface was recovered from 5.1 mm to 1.3 mm. Clinical results were excellent in 17 cases, good in 18 cases, fair in 3 cases, and poor in 5 cases. 10 cases developed postoperative complications such as skin necrosis, heel pain, limitation of motion of ankle and subtalar arthritis. Conclusion: The extensile lateral approach is valuable for the comminuted intraarticular fractures of calcaneus that enables accurate anatomical reduction and rigid internal fixation by providing direct exposure of subtalar joint.

• Korean Journal of Applied Biomechanics
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• 제20권4호
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• pp.381-386
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• 2010

This study examined the changes in the walking pattern during level walking under low illumination conditions. Fourteen male subjects ($22.1{\pm}2.21$ years, $174{\pm}3.74\;cm$, $68.86{\pm}10.81\;kg$) with normal vision and no disabilities were enrolled in this study. All experiments were performed on a level walkway with three conditions: normal walking (preferred & low speed) and walking with low illumination. 3D motion capturing system was used for acquisition and analysis of the walking motion data with a sampling frequency of 120Hz. The walking speed, normalized jerk(NJ) at the center of mass(COM), wrist and heel, knee and elbow joint angle, ratio of the knee joint angle to elbow joint angle and the toe clearance on stance phase were used to compare the differences in walking pattern between the two illumination conditions, The results showed that the walking speed and joint angles decreased in low illumination, whereas the NJ and toe minimum clearance increased. In low illumination, most variables were similar to effects of low speed walking, but toe clearance was different from the effects of low speed. These results can be used as primary data for examining the changes in the level walking pattern of young adults under low illumination. Further study will be needed to compare these results in young adults with those in the elderly.

• Journal of the Korean Society of Marine Environment & Safety
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• 제23권3호
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• pp.266-272
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• 2017

In this study, it was simulated and analyzed the evacuation safety to identify the cadets' evacuation time by using maritimeEXODUS which is applied IMO MSC.1/Circ.1238 theory as well as the trim and heel which are the major factor of reducing the ship evacuation speed. In addition, this study carried out a simulation through the special program for fire analysis - FDS (Fire Dynamics Simulator) in order to find the effective evacuation time, i.e. life survival time. Particularly, this study did comparative analysis of the influence on the survival of cadets based on the collected simulation data by fire size and sort. As a result of the analysis, It was analyzed the Evacuation Allowable Limit Temperature $60^{\circ}C$ and resulted that there is no influence in evacuation by temperature. As a result of the analysis on visibility evacuation limit 5 m, it was found that the only one evacuation rallying point could not meet the evacuation safety. However, it derived the perfect evacuation safety under the condition of two rallying points available on wood fire. In case of Kerosene, it was satisfied the evacuation safety if the heeling was under $10^{\circ}$. Moreover, it could not meet the evacuation safety by evacuating through upper deck although there were two evacuation rallying points. When it was set by the lifeboat descending maximum angle-$20^{\circ}heel$ and $10^{\circ}trim$ which was described in SOLAS regulation, it was simulated that the wood fire having two evacuation rallying points in the center of the ship satisfied the evacuation safety.

• Journal of the Korean Home Economics Association
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• 제41권6호
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• pp.1-12
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• 2003

The purpose of this study were to analyze the anthropometric data of feet of Korean women with aging, to categorize the women's foot shapes, and to compare the shoe size according to the foot shapes in order to provide the basic information for more comfortable shoes. Subjects of this study were 181 women over age 20. They were measured with the direct measurement method and the indirect measurement method. 26 items were measured from the right foot and 6 items were taken on foot outline. Factor analysis, cluster analysis, analysis of variance, post-hoc test, and cross tabs were peformed for statistical analysis of the data by SPSS program. There were significant differences in height items, breadth items, girth items, and angle items by subjects' age. The older subjects' feet were wide and thick with big deformity on toes. The arch height of the older ones was low. This implicates that the degree of deformity on toes, the foot ratio, the foot girth, the foot breath and the arch height as well as the foot length are needed to be considered in developing comfortable shoes. Nine foot construction factors were extracted by the factor analysis of anthropometric measurements; foot size factor, heel and instep factor, malleolus lateralis factor, malleolus medialis factor, foot shape factor, shape of toes factor, heel height factor, big toe height factor, and internal factor. On the basis of the cluster analysis, three different foot shapes were categorized. Type 1 was large and wide foot with little deformity on little toe. Type 2 was medium foot with deformation of big toe, and with the lowest arch height. Type 3 was small and narrow foot with the highest arch height. Distribution of shoe size according to the foot shape was analyzed. The ball of foot breath was of wide distribution than the ball of foot girth. This implicates that girth items and breath items of the foot should be enclosed for the same foot length in the shoe sizing system.

• Journal of the Society of Naval Architects of Korea
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• 제43권4호
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• pp.414-421
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• 2006

Yacht is operated by wind-driven thrust on the saii, but also experiencing the side force. Thus the keel attached on the bottom of main hull prevents it from flowing sideway. Since the keel affects the stability and thrust of yacht, its selection is one of the most important factor in design. In the present paper the correlation between yacht hull and keel was investigated. through comparison of forces measured at various combinations of heeling and leeway angles with and without keel. Keel-only test was also performed to find out the drag and lift characteristics of keel itself. finally three different types of keel, i.e. fin keel, bulb keel and winglet keel were tested to compare their advantages and drawbacks.

• Proceedings of the ESK Conference
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• 대한인간공학회 1997년도 춘계학술대회논문집
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• pp.297-303
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• 1997

This study was initiated to investigate suitability of men's dress shoe sizes made for young men. Experiments were performed on 172 men for 19 to 29 years of age. Nine dimensions were measured from the subject's right foot and 11 dimensions were measrued from the outline of the foot. The data were analyzed for six different groups. The subjects were grouped by their dress shoe size or the ratio of the foot width to foot length. The result of the experiments lead to the following conclusions: 1. Foot length, metatarsal width and heel width were significantly different among the small, medium and large dress shoe size groups. 2. No significant differences in front foot angle and the inside metatarsal width were found among the above three groups. 3. The difference between wearing shoe size and the foot length was larger for the subjects with wide foot shape.