• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.865-870
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• 2004

This paper describes the generation of chordal surface for various shell structures, such as automobile bodies, plastic injection mold components and shell metal parts. After one-layered tetrahedral mesh is generated by an advancing front algorithm, the chordal surface is generated by cutting a tetrahedral element. It is generated one or two elements at a tetrahedral element and the chordal surface is composed with triangular or quadrilateral elements. This algorithm has been tested on several models with rib structure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.835-846
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• 2011

In medial opening wedge high tibial osteotomy (OWHTO), researchers have reported critical problems caused by unexpected changes in the tibial posterior-slope angle. This unexpected change can be analyzed, but there is no general solution for cases with an oblique hinge axis and cut plane. We propose a general analysis model for OWHTO. We first evaluate the effects according to variation in the hinge axis and tibial cut plane and then define an ideal correction axis. This ideal axis, called the virtual tibial correction axis, is not on the tibial cut plane in general. In this paper, we also present an evaluation of feasibility of the proposed analysis model.

• ETRI Journal
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• v.29 no.4
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• pp.507-515
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• 2007

Skeleton transform of which the medial axis transform is the most popular has been proposed as a useful shape abstraction tool for the representation and modeling of human posture. This paper explains this proposition with a description of the areas in which skeletons could serve to enable the representation of shapes. We present algorithms for two-dimensional posture modeling using the developed simplified shock graph (SSG). The efficacy of SSG extracted feature vectors as shape descriptors are also evaluated using three different classifiers, namely, decision tree, multilayer perceptron, and support vector machine. The paper concludes with a discussion of the issues involved in using shock graphs to model and classify human postures.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.105-115
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• 2006

Thickness is a commonly used parameter in product design and manufacture. Its intuitive definition as the smallest dimension of a cross-section or the minimum distance between two opposite surfaces is ambiguous for intricate solids, and there is very little reported work in automatic computation of thickness. We present three generic definitions of thickness: interior thickness of points inside an object, exterior thickness for points on the object surface, and radiographic thickness along a view direction. Methods for computing and displaying the respective thickness values are also presented. The internal thickness distribution is obtained by peeling or successive skin removal, eventually revealing the object skeleton (similar to medial axis transformation). Another method involves radiographic scanning along a viewing direction, with minimum, maximum and total thickness options, displayed on the surface of the object. The algorithms have been implemented using an efficient voxel based representation that can handle up to one billion voxels (1000 per axis), coupled with a near-real time display scheme that uses a look-up table based on voxel neighborhood configurations. Three different types of intricate objects: industrial (press cylinder casting), sculpture (Ganesha idol), and medical (pelvic bone) were used for successfully testing the algorithms. The results are found to be useful for early evaluation of manufacturability and other lifecycle considerations.

• Journal of the Korean Geographical Society
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• v.41 no.2 s.113
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• pp.188-194
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• 2006

Three-dimensional topological data is essential for 3D modeling and application such as emergency management and 3D network analysis. This paper reviewed current 3D topological data model and developed a method to construct 3D topological node-relation data structure from 2D computer aided design (CAD) data. The method needed two steps with medial axis-transformation and topological node-relation algorithms. Using a medial-axis transformation algorithm, the first step is to extract skeleton from wall data that was drawn polygon or double line in a CAD data. The second step is to build a topological node-relation structure by converting rooms to nodes and the relations between rooms to links. So, links represent adjacency and connectivity between nodes (rooms). As a result, with the conversion method 3D topological data for micro-level sub-unit of each building can be easily constructed from CAD data that are commonly used to design a building as a blueprint.

• Journal of Korean Foot and Ankle Society
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• v.27 no.2
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• pp.71-74
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• 2023

A medial opening wedge supramalleolar osteotomy (SMO) introduced by Takakura et al. is a useful realignment procedure for patients with ankle joint arthritis and varus malalignment by shifting the weight-bearing axis laterally and redistributing the loads on the ankle joint. When pain persists after arthroscopic microfracture in patients with medial osteochondral lesion of the talus (OLT), redo arthroscopy, osteochondral autograft transplantation, autologous chondrocyte implantation, or matrix-induced chondrogenesis might be indicated. On the other hand, there is insufficient scientific evidence for realignment surgery through SMO, while the effect of realignment surgery has been studied consecutively for osteochondral lesions of the knee. Therefore, this paper reports a patient with medial OLT who underwent redo arthroscopy combined with SMO for persistent pain after primary arthroscopic microfracture.

• Physical Therapy Rehabilitation Science
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• v.5 no.3
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• pp.113-119
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• 2016

Objective: The effect of abdominal expansion maneuver (AEM) and abdominal draw-in maneuver (ADIM) on postural control in an unsupported position in stroke patients. Design: Randomized controlled trial. Methods: A total of 36 persons with hemiplegic stroke participated in this study. The subjects were randomly divided into an AEM experimental group (n=12), an experimental ADIM group (n=12), and a control group (n=12). We collected the general characteristics of all subjects and the pre-test results before the intervention and after 4 weeks of the intervention. The trunk stabilization training of the ADIM and AEM group were performed 15 minutes a day, 3 times a week for 4 weeks, and general physical therapy was performed 2 times a day, 30 minutes per session, 5 times a week for all three groups. The control group received joint mobilizations, muscle strengthening, endurance strengthening, and gait exercises along with treatment of the central nervous system, such as neuro-developmental treatment, mat, and gait training. The AEM is an inspiratory phase of tidal breathing expanding the lateral lower ribcage in a lateral direction with minimal superior movements of the chest. Then the lower abdomen expands and the navel moves in an anterior-caudal direction. The ADIM is a repeated contraction and relaxation of the anal sphincter during inspiration. The navel pulls the lower abdomen to the direction of the spine without the movement of the trunk and pelvis. Results: Before and after the interventions, medial-lateral axis movement distance, anterior-posterior axis movement distance, sway mean velocity, and sway area 95% was a statistically significant change in all three groups (p<0.05). The post-hoc test showed a significant improvement in medial-lateral axis movement distance, anterior-posterior axis movement distance, sway mean velocity, and sway area in the AEM group compared with the control group, and in the ADIM group compared with the control group (p<0.05). Conclusions: In conclusion, both AEM training and ADIM training are necessary interventions to maintain the independent sitting position according to the characteristics of the patient.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.7-10
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• 2008

We present a technique for constructing a digital elevation model (DEM) from contours. The elevation of each ground point in DEM is computed by interpolating the heights of the two adjacent contours of the point. The technique decomposes each sub-domain between adjacent contours into a set of sub-regions. The decomposition is accomplished by constructing a medial axis of the sub-domain. Each sub-region in the decomposition is classified into a variety of terrain features like hillsides, valleys, ridges, etc. The elevations of points are interpolated with different methods according to terrain features they belong to. For a given point in hillside, an approximate gradient line passing through the point is determined and the elevation of the point is interpolated from the known elevations of the two adjacent contours along the approximate gradient line. The univariate monotone rational Hermite spline is used for the interpolation. The DEM constructed by the technique is to be used to orthorectify the high-resolution KOMPSAT3 imagery.

• Journal of Veterinary Clinics
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• v.39 no.3
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• pp.93-99
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• 2022

The present study was performed to compare cranial tibial wedge osteotomy (CTWO) and tibial plateau leveling osteotomy (TPLO) through radiographic evaluation. The experiment was conducted with five cadaver dogs [mean (± SD) weight, 32.9 ± 4.1 kg; mean (± SD) age, 6 ± 2 years; three males and two females] euthanized for reasons unrelated to this study. The cadaver dogs consisted of German Shepherd (n = 3), Belgian Malinois (n = 1), and mixed breed (n = 1). CTWO and TPLO were carried out by the standard surgical method. Radiographic evaluation was performed by comparing several factors, including the flexion and extension angles, the anatomical mechanical axis angle (AMA-angle), tibial length, patellar height measurement using the Labelle-Laurin method, mechanical medial proximal tibial angle (mMPTA), mechanical medial distal tibial angle (mMDTA), and frontal plane alignment (FPA). Both the CTWO and the TPLO groups showed significantly increased flexion angles after surgery. Only the CTWO group had significantly increased extension angle. Although both groups showed significant decreases in the AMA-angle, the mechanical axis moved cranially against the anatomical axis only in the CTWO group. The patellar height was significantly lowered in the CTWO group. No significant differences were found in mMPTA, mMDTA, or FPA. In conclusion, radiographic comparison revealed more changes in CTWO group than in TPLO group.

• The Journal of Korean Physical Therapy
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• v.27 no.2
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• pp.85-88
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• 2015

Purpose: The purpose of this study was to investigate the effects of active abduction exercise of the great toe on the medial and lateral sesamoid bones in hallux valgus (HV) patients by measuring radiography. Methods: In this study 27 young subjects were separated into two groups (normal group and HV group). Two pictures were taken by radiography while maintaining resting and while holding maximal active abduction of the great toe in sitting position on an x-ray table. All radiographs were used to measure the distance of the medial and lateral sesamoid bone from the longitudinal axis of the first metatarsal bone, respectively. Paired t-test was used for analysis of the resting and active abduction exercise in groups. Independent t-test was used to evaluate statistical significance between normal group and HV group. The statistical significance level was p<0.05. Results: In active abduction exercise of the normal group, distance of the medial and lateral sesamoid bones was not significantly different compared to resting condition. In active abduction exercise of the HV group, change of distance of the medial and lateral sesamoid bones showed statistically significant difference compared to resting condition. The distance between the medial sesamoid bone showed a more significant decrease in the HV vs. normal group, while the distance between the lateral sesamoid bone was significantly greater in the HV vs. normal group. Conclusion: These findings suggest that active abduction exercises, to reduce or prevent deterioration of the HV angle, should be considered for sesamoid bone displacement to improve muscle balance in the great toe.