• Journal of architectural history
• /
• v.21 no.2
• /
• pp.21-36
• /
• 2012

As wooden construction developed, it was observed that the rafters with corners changed to angled rafters. The change from rafters to angle rafters means that the angle rafters became the most important member in supporting the roof weight as the construction scale increased and structurally developed. The specific installation methods of angle rafters were all unique in Korea, China, and Japan. In East Asia, the angle of the angle rafter gradually decreased along with the development of construction. However, in Joseon Dynasty Korea, the angle of the angle rafter was larger than that of the Gorye era because the method of fixing the corner of the roof more firmly by building the fan-shaped rafter was utilized. The changes to the angle rafter installation method is a unique characteristic of Korea, in that it was developed in a totally different way from the methods used in China and Japan.

• The Journal of Korean Physical Therapy
• /
• v.32 no.2
• /
• pp.94-100
• /
• 2020

Purpose: This study examined the effects of the abdominal hollowing technique applied during plank exercises at different shoulder angles between the ground and the humerus on the abdominal muscle activity Methods: The subjects were 36 male volunteers. They were randomized to perform plank exercises or plank exercises using the hollowing technique at 80˚, 90˚, 100˚, and 110˚ between the ground and the humerus. The abdominis muscles were measured using a surface electromyogram. Independent t-tests examined the changes in the activity of these muscles according to the two exercise methods at each angle. The changes in muscle activity were examined according to the selected angles by one-way analysis of variance. Results: The activity of abdominal muscles was investigated according to the angle between the ground and the humerus during the plank exercise. As a result, the muscle activity increased significantly with decreasing angle in the rectus abdominis, external oblique, and internal oblique·transverse abdominis muscles (p<0.05). In terms of the changes in abdominal muscle activity after hollowing plank exercises at the given angles between the ground and the humerus, an increase in angle resulted in a statistically significant increase in the rectus abdominis muscle activity (p<0.05). The activities of the rectus abdominis, external oblique, and internal oblique/transverse abdominis muscles after hollowing plank exercises showed statistically significant increases (p<0.05) compared to those after plank exercises. Conclusion: The hollowing technique and the increase in the angle between the ground and the humerus may be an effective exercise method for increasing the muscle activity of the abdominis muscles.

• Journal of International Academy of Physical Therapy Research
• /
• v.1 no.2
• /
• pp.162-168
• /
• 2010

Low back pain is a common phenomenon among the golfers. In an attempt to understand low back pain, the kinematic changes and golf swing motion analysis has been performed to focus on lumbar spine in pro. golfers. According to the swing pattern, significant variations of the lumbar joint forces and loads has related with muscles activities so the motion analysis of lumbar spine were discussed. The purpose of this study was to analyze motion of lumbar spine and it was to compare joint force during golf swing in pro. golfers. The swing motion of the subjects was tracked using a 3D motion analysis system by Motion Analysis Ltd. and SIMM software. The angle changes of lumbar spine rapidly in vx direction during the top back swing and the finish and in vy direction during the follow through and in vz direction during the down swing and the impact(Subject A). The angle changes of lumbar spine rapidly in vx direction during the top back swing and in vy direction during the down swing, the impact and the follow through and in vz direction during the down swing(Subject B). In conclusion, subject A and B both show sudden angle changes between 1st-3rd lumbar spine and 4th-5th lumbar spine during the stage from address to top back swing which caused by over upper body twisting.

• Korean Journal of Applied Biomechanics
• /
• v.15 no.3
• /
• pp.95-104
• /
• 2005

To know the proper setup posture for the various clubs, changes of setup variables according to the change of golf club length was investigated. Swing motions of three male low handicappers including a professional were taken using two high-speed videocameras. Four clubs iron 7, iron 5, iron 3 and driver (wood 1) were selected for this experiment. Three dimensional motion analysis techniques were used to get the kinematical variables. Mathcad and Kwon3D motion analysis program were used to analyze the position, distance and angle data in three dimensions. The variables divided into three categories 1) position and width of anterior-posterior direction 2) position and width of lateral direction 3) angles and evaluated based on the theories of many good golf teachers. Major findings of this study were as follows. 1.The stance (distance between ankle joints) was increased as the length of the club increased but the increasing width was not large. It ranges from 5cm to 10cm and professional player showed small changes. 2. Forward lean angle of trunk was decreased (more erected) as the length of the club increased. It ranges from 30 degrees for iron7 to 25 degrees for driver. 3. Angle between horizontal and right shoulder were increased as the length of the club increased. It ranges from 10 degrees to 20 degrees and professional player showed small changes. 4. Anterior-posterior position of the shoulders were located in front of the foot for all clubs and the difference between the shoulder and knee position was decreased as the length of the club increased. 5. Anterior-posterior position of grip (hand) was located almost beneath the shoulders (2.5cm front) for iron7, but it increased to 10cm for the driver. This grip adjustment makes the height of the posture increased only 5cm from iron7 to driver. 6. Lateral position of grip located at 5cm left for the face of iron7, but it located at the right side (behind) for the face of driver. 7. Lateral position of the ball located at the 40%(15cm) of stance from left ankle for iron7 and located at the 10% (5cm) of stance for driver. 8. Head always located at the right side of the stance and the midpoint of the eyes located at the 37% of stance from the right ankle for all clubs. This means that the axis of swing always maintained consistently for all clubs. 9. Left foot opened to the target for all subject and clubs. The maximum open angle was 25 degrees. Overall result shows that the changes of the setup variables vary only small ranges from iron7 to driver. Paradoxically it could be concluded that the failure of swing result from the excessive changes of setup not from the incorrect changes. These findings will be useful for evaluating the setup motion of golf swing and helpful to most golfers.

• Korean Journal of Applied Biomechanics
• /
• v.33 no.2
• /
• pp.73-83
• /
• 2023

Objective: Adolescent idiopathic scoliosis patients make up 40% of all scoliosis patients, and it is likely to increase even more because of the increase in sitting times due to the pandemic. Method: The subject of this study was a 16-year-old female student. The Cobb's Angle at initial value was 42° at the thoracic and 33° at the lumbar. The subject's height was 161.6 cm, and the type of scoliosis was 3CL. The brace was built with fabric materials with the size information from the X-ray information and actual measurements. The brace was made for the adolescents to wear for a longer time by making them put pressure on the same pressure points of the existing braces. The subjects were required to wear the device for 16 hours every day for three months. Additional features to check the pressure and time were synchronized through an app for easier communication and management with the responsible investigator. Results: After wearing the 3D Fabric brace, Cobb's angle changed from 42° to 33° at the thoracic and 33° to 23° at the lumbar. The ATR changed from 9° to 8° at the thoracic and 11° to 6° at the lumbar. As a result, the changes in the ATR angle do relate to the decrease of Cobb's angle, which made the angle of scoliosis that is bent in a three-dimensional way improve, making the height of the subject increase from 161.6 cm to 163.5 cm. Conclusion: Through this study, developing a brace that is made in the form of the 3CL to align the strap direction and putting pressure on the proper pressure points makes Cobb's angle and the ATR smaller. This means that there is a positive effect on the changes in height. A brace made of light fabric material is a good brace to help treat adolescent idiopathic scoliosis. There was an opinion that it is more comfortable to wear than existing braces, but it seems necessary to conduct a quantitative study about the before and after of wearing the brace and a survey for Korean specific cases.

• The korean journal of orthodontics
• /
• v.53 no.1
• /
• pp.35-44
• /
• 2023

Objective: Surgically assisted maxillary protraction is an alternative protocol in severe Class III cases or after the adolescent growth spurt involving increased maxillary advancement. Correction of the maxillary deficiency has been suggested to improve pharyngeal airway dimensions. Therefore, this retrospective study aimed to analyze the airway changes cephalometrically following surgically assisted maxillary protraction with skeletal anchorage and Class III elastics. Methods: The study population consisted of 15 Class III patients treated with surgically assisted maxillary protraction combined with skeletal anchorage and Class III elastics (mean age: 12.9 ± 1.2 years). Growth changes were initially assessed for a mean of 5.5 ± 1.6 months prior to treatment. Airway and skeletal changes in the control (T0), pre-protraction (T1), post-protraction (T2), and follow-up (T3) periods were monitored and compared using lateral cephalometric radiographs. Statistical significance was set at p < 0.05. Results: The skeletal or airway parameters showed no statistically significant changes during the control period. Sella to nasion angle, N perpendicular to A, Point A to Point B angle, and Frankfort plane to mandibular plane angle increased significantly during the maxillary protraction period (p < 0.05), but no significant changes were observed in airway parameters (p > 0.05). No statistically significant changes were observed in the airway parameters in the follow-up period either. However, Sella to Gonion distance increased significantly (p < 0.05) during the follow-up period. Conclusions: No significant changes in pharyngeal airway parameters were found during the control, maxillary protraction, and follow-up periods. Moreover, the significant increases in the skeletal parameters during maxillary protraction were maintained in the long-term.

• Current Optics and Photonics
• /
• v.4 no.6
• /
• pp.500-508
• /
• 2020

The rifling angle of artillery is an important parameter, and its determination plays a key role in the stability, hit rate, accuracy and service life of artillery. In this study, we propose an optical measurement method for the rifling angle based on angle error correction. The method is based on the principle of geometrical optics imaging, where the rifling on the inner wall of the artillery barrel is imaged on a CCD camera target surface by an optical system. When the measurement system moves in the barrel, the rifling image rotates accordingly. According to the relationship between the rotation angle of the rifling image and the travel distance of the measurement system, different types of rifling equations are established. Solving equations of the rifling angle are deduced according to the definition of the rifling angle. Furthermore, we added an angle error correction function to the method that is based on the theory of dynamic optics. This function can measure and correct the angle error caused by the posture change of the measurement system. Thus, the rifling angle measurement accuracy is effectively improved. Finally, we simulated and analyzed the influence of parameter changes of the measurement system on rifling angle measurement accuracy. The simulation results show that the rifling angle measurement method has high measurement accuracy, and the method can be applied to different types of rifling angle measurements. The method provides the theoretical basis for the development of a high-precision rifling measurement system in the future.

• Earthquakes and Structures
• /
• v.20 no.4
• /
• pp.389-403
• /
• 2021

Skewed bridges, being irregular structures with complicated dynamic behavior, are more susceptible to earthquake damage. Reliable seismic-resistant design of skewed bridges can be achieved by accurate determination of nonlinear seismic demands. However, the effect of geometric characteristics on the response modification factor (R-factor) is not accounted for in bridge design practices. This study attempts to investigate the effects of changes in the number of spans, skew angle and bearing stiffness on R-factor values and to assess the seismic fragility of skewed bridges. Results indicated that changes in the skew angle had no significant effect on R-factor values which were in consonance with code-prescribed R values. Also, unlike the increase in the number of spans that resulted in a decrease in the R-factor, the increase in bearing stiffness led to higher R-factor values. Findings of the fragility analysis implied that although the increase in the number of spans, as well as the increase in the skew angle, led to a higher failure probability, greater values of bearing stiffness reduced the collapse probability. For practicing design engineers, it is recommended that maximum demands on substructure elements to be calculated when the excitation angle is applied along the principal axes of skewed bridges.

• The Journal of Korean Physical Therapy
• /
• v.35 no.2
• /
• pp.53-57
• /
• 2023

Purpose: The purpose of this study was to compare the changes in the muscle activation of the quadriceps muscle (rectus femoris, vastus lateralis, vastus medialis) during the stand-to-sit (StandTS) movement according to the plantar flexion angle of the ankle joint. Methods: A total of 22 healthy young females participated in this study. During the StandTS under the three conditions (plantarflexion angle 0°, 20°, and 45° of the ankle), electromyography (EMG) data (% maximum voluntary iso¬metric contraction) of the rectus femoris, vastus lateralis, and vastus medialis were recorded using a wireless surface EMG system. Results: There was a significant difference in the muscle activation of rectus femoris, vastus lateralis, and vastus medialis according to the plantar flexion angle (0°, 20°, and 45°) of the ankle. The muscle activation of the quadriceps was the highest at a 45° angle of plantarflexion and the lowest at 0°. One-way repeated ANOVA was used to analyze the muscle activation data of the lower extremity muscles according to the angle of the ankle joint. Conclusion: Based on the results of our study, it was confirmed that the muscle activity of the quadriceps can be increased even in the StandTS movement, which involves the eccentric contraction of the quadriceps muscle. This suggests that maintaining a plantar flexion posture for a long time, say by wearing high-heeled shoes, can quickly cause muscle fatigue in the lower-limb muscles, which can cause a decrease in balance ability leading to falls.

• Journal of Fashion Business
• /
• v.15 no.1
• /
• pp.80-91
• /
• 2011

The purpose of this study is to evaluate the differences of visual effects and visual images by variations in shoulder angle and shoulder width of power shoulder jacket. The stimuli are 5 samples: One control group, 2 variations of the angle of shoulder line and 2 variations of the width of shoulder line. The data has been obtained from 87 fashion design majors. The data has been analyzed by Factor Analysis, Anova, Scheffe's Test and the Correlation Analysis. The results of the study are as follows: The visual images by the angle and the width of shoulder line of power shoulder jacket are composed of 4 factors : attention, stiffness and softness, masculinity, and trendiness. Among these factors, attention factor is estimated by the most important factor. The visual effects by the angle and the width of shoulder line of power shoulder jacket are composed of 3 factors : whole silhouette, neck and arm figure, upper body figure. In these factors, the whole silhouette is estimated by the most important factor. The power shoulder jacket with extreme changes in shoulder angle has double images: it looks trendy and classy but also gives an awkward image. In case of changes in shoulder width, the visual evaluation shows big differences with the degree of expansion. The visual evaluation with variation in angle has stronger image and effect than that in width. The power shoulder jacket trend itself is also evaluated that variation in angle reflects the trend better than that in width.