• Journal of Korean Foot and Ankle Society
• /
• v.11 no.2
• /
• pp.141-144
• /
• 2007

Purpose: To statistically evaluate the contributing role of the 3 radiographic factors (Obliquity, Asymmetry, Joint deviation) of the hallux valgus interphalangeus with comparison to the normal control group. Materials and Methods: The study is based on the standing foot AP radiographs of the 77 feet (56 patients) of the hallux valgus interphalangeus out of 119 feet of randomly sampled patients of the age range 20 to 60. Fractures or other foot disorders have been excluded. Obliquity, asymmetry and joint deviation factors formed by proximal and distal phalanges of hallux are measured by one observer and evaluated the statistical significance of the contribution of the 3 factors to the hallux interphalangeal angle (HIA). Results: The average age of the patients were 36.0 years old and average HIA was $14.5^{\circ}{\pm}2.8^{\circ}$. Obliquity was measured $4.8^{\circ}{\pm}2.90^{\circ}$, asymmetry $8.2^{\circ}{\pm}3.28^{\circ}$ and joint deviation $2.0^{\circ}{\pm}1.85^{\circ}$. All 3 factors showed the statistical significance as the contributing factors to the HIA and among them, the asymmetry played the biggest role (p<0.05). Conclusion: Hallux interphalangeal angle is formed by 3 radiographic factors (Obliquity, Asymmetry, Joint deviation), and among them the asymmetry factor plays the biggest role.

• Journal of Positioning, Navigation, and Timing
• /
• v.8 no.2
• /
• pp.59-68
• /
• 2019

This paper proposed a method to estimate the vertical delay from the slant delay, which can improve accuracy of the ionospheric correction of SBAS. Proposed method used Chapman profile which is a model for the vertical electron density distribution of the ionosphere. In the proposed method, we assumed that parameters of Chapman profile are given and the vertical ionospheric can be modeled with linear function. We also divided ionosphere into multi-layer. For the verification, we converted slant ionospheric delays to vertical ionospheric delays by using the proposed method and generated the ionospheric correction of SBAS with vertical delays. We used International Reference Ionosphere (IRI) model for the simulation to verification. As a result, the accuracy of ionospheric correction from proposed method has been improved for 17.3% in daytime, 10.2% in evening, 2.1% in nighttime, compared with correction from thin shell model. Finally, we verified the method in the SBAS user domain, by comparing slant ionospheric delays of users. Using the proposed method, root mean square value of slant delay error decreased for 23.6% and max error value decreased for 27.2%.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.15 no.1
• /
• pp.21-32
• /
• 2003

In this study, the reliability design method developed by Hanzawa et al. in 1996 for calculation of the expected damage to armor blocks of a horizontally composite breakwater is extended to take into account the variability in wave direction such as directional spreading of waves, obliquity of the design principal wave direction from the shore-normal direction, and its variation about the design value. To calculate the transformation of random directional waves. the model developed by Kweon et al. in 1997 is used instead of Goda's model, which was developed in 1975 for unidirectional random waves normally incident to a straight coast with parallel depth contours and has been used by Hanzawa et al. It was found that the variability in wave direction had great influence on the computed expected damage to armor blocks. The previous design, which disregarded wave directionality, could either overestimate or underestimate the expected damage by a factor of two depending on water depth and seabed slope, if the assumption of the present study that the stability formula for breakwater armor blocks proposed for normal incidence can be used for obliquely incident waves is valid.

• Journal of the Korean Orthopaedic Association
• /
• v.56 no.3
• /
• pp.215-223
• /
• 2021

Purpose: Distal radius fractures in youth are treated conservatively in most cases, but there are some cases of redisplacement in the follow-up period after cast immobilization, even after complete reduction. This study examined the risk factors of redisplacement in reduced unstable distal radius fractures. Materials and Methods: From February 2011 to June 2018, 44 unstable distal radius fractures were managed with a closed reduction and cast immobilization. The patients were aged between 6 and 14 years. The cases of redisplacement were analyzed with the fracture characteristics (fracture obliquity, fracture level ratio, ulnar fracture combined), cast qualities (gap index, cast index, 3 point index, and radius-2nd metacarpal angle) and host factors (age, sex). Results: The mean angulation in the union was 9.2° (0°-32.8°). In the categorical grouping 29 cases were within 10° angulation, and 15 cases were more than 10°. No significant differences in the factors of the cast indices or host factors were noted. The meaningful factor was the fracture level calculated by the relative width of the fracture site divided by the sum of width of diaphysis and epiphysis (p=0.001) and combined ulnar fracture (p=0.019). Conclusion: Unstable distal radius fractures should be treated with more stubborn guidelines lest the fracture loses its anatomical alignment. In particular, in patients with less remodeling power, operative treatment would secure a better result if the fracture occurs in a more proximal location.