• Journal of Trauma and Injury
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• v.18 no.1
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• pp.64-69
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• 2005

Purpose: We report the radiologic and the clinical results for surgical treatment of calcaneal fractures involving the subtalar joint. Methods: We evaluated the findings of radiographs and computed tomographs of 39 patients (40 cases) with intra-articular calcaneal fractures. The fractures were treated with open reduction via an extended lateral approach and internal fixation using a plate. We assessed the radiologic results, such as the $B{\ddot{o}}hler$ angle, the Gissane angle, and the height/width ratio. We assessed the clinical results based on the critieria of Salama et al. Results: According to the Essex-Lopresti classification, 9 cases were classified as tongue type and 31 cases as joint depression type. According to the Sanders classification, 10 cases were classified as type IIA, 4 cases as IIB, 16 cases as IIIAB, 4 cases as IIIAC, and 6 cases as type IV. The mean preoperative $B{\ddot{o}}hler$ angle was 7.7, the mean postoperative $B{\ddot{o}}hler$ angle was 21.1, and the mean last follow-up $B{\ddot{o}}hler$ angle was 16.8. Clinical results classified as 10 excellent, 13 good, 11 fair, and 6 poor. Conclusion: In the treatment of intra-articular fractures of the calcaneus, open reduction via an extended lateral approach seems to be a useful method in that it can provide direct exposure of the subtalar joint with little morbidity.

• Structural Engineering and Mechanics
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• v.44 no.1
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• pp.35-49
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• 2012

A series of fatigue test were carried out on scarfed lap joints (SLJ) using in airfoil siding to explore the effect of structural details, such as rows of rivets, lap angles, on its fatigue performance. Finite element (FE) analysis was employed to explore the effect of lap angle on load transfer and the stress evolution around the rivet hole. At last, the fatigue lives were predicted by nominal stress approach and critical plane approach. Both of the test results and predicted results showed that fatigue life of SLJ was remarkably increased after introducing lap angle into the faying surface. Specimen with the lap angle of $1.68^{\circ}$ exhibits the best fatigue performance in the present study.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1254-1262
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• 2014

Magneto-electric encoders have been widely used in industry and military applications because of their good shock resistance, small volume, and convenient data processing. However, the characteristics of a magneto-electric encoder's signal generator and hall sensor changes minimally with temperature variation. These changes cause an angle drift. The main purpose of this study is to construct the compensation system of a neural network and constantly update weight coefficients of temperature correction by finite iteration calculation so that the angle value modified can approach the angle value at the target temperature. This approach is used in adaptive correction of the angle value.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.2
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• pp.271-278
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• 1999

An alternative panel flutter approach utilizing minimum angle is presented. The minimum angle is the lowest value among the angles between modes i and j at a certain pressure condition. This method utilizes eigenvectors rather than eigenvalues. Cross-ply composite plates are considered in this study. A remarkable result of this investigation is that the angle always dropped gradually to zero for all presented examples

• Journal of Korean Foot and Ankle Society
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• v.11 no.1
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• pp.79-85
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• 2007

Purpose: To evaluate the clinical efficacy of the limited posterior approach for the surgical treatment of intraarticular fracture of calcaneus. Materials and Methods: From March 2000 to February 2006, we studied retrospectively 186 patients, 203 cases who were treated with open reduction and internal fixation through limited posterior approach and were followed up for more than 1 year. The clinical results were evaluated with Creighton-Nebraska score and circle draw test after 1 year. We checked simple AP, lateral, axial and Broden's view preoperatively and 1 year after surgery, and compared $B{\ddot{o}}hler$ angle and Gissane angle. Results: By Creighton-Nebraska score, Sanders type 2 was 86.4, type 3 was 74.3, type 4 was 62.4. And by circle draw test, type 2 was 8.9 cm, type 3 was 7.2 cm, type 4 was 5.9 cm. $B{\ddot{o}}hler$ angle and Gissane angle were $7.6^{\circ}$, $102.4^{\circ}$, and it increased to $23.5^{\circ}$, $128.6^{\circ}$ after postoperative 1 year. Conclusion: Limited posterior approach for the surgical treatment of intraarticular fracture of calcaneus was considered to an effective treatment modality.

• Journal of Korean Foot and Ankle Society
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• v.13 no.1
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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.

• Journal of Korean Foot and Ankle Society
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• v.21 no.1
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• pp.27-32
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• 2017

Purpose: Bone grafting is often necessary to maintain a reduction and prevent delayed collapse of reduced fracture in a treatment of severely displaced comminuted intra-articular calcaneal fractures. Herein, we analyzed the usefulness and necessary conditions to perform tricortical-allobone grafting in open reduction of calcaneal fracture via the Ollier approach. Materials and Methods: We performed a retrospective review of 57 intra-articular calcaneal fractures that underwent an operation via the Ollier approach between April 2009 and April 2015. They were divided into two groups: Group 1 (n=17) included those with tricortical-allobone grafts underneath the posterior facet fragment, and group 2 (n=40) included cases without a bone graft. We measured the $B{\ddot{o}}hler$ angle, Gissane angle, height, and width of the calcaneus at preoperative, postoperative, and final follow-up radiograph. We measured the sagittal rotational angle of the posterior facet fragment of preoperative computed tomography to analyze the effect and necessary conditions for bone grafting. We also reviewed the clinical results by the American Orthopaedic Foot and Ankle Society (AOFAS) scale, visual analogue scale (VAS), and any complications. Results: According to the Sanders classification, there were 3 type-II fractures, 12 type-III fractures, and 2 type-IV fractures in Group 1; whereas in Group 2, there were 26 type-II fractures, 13 type-III fractures, and 1 type-IV fracture (p=0.002). Regarding the preoperative radiologic parameters, there were significant differences in the $B{\ddot{o}}hler$ angle (p=0.006), Gissane angle (p=0.043), and rotational angle of the posterior facet fragment (p=0.001). No significant difference was observed in the preoperative calcaneal height and width, as well as postoperative radiologic parameters. There was no significant clinical difference between the two groups (p=0.546). Conclusion: We suggest that a tricortical-allobone graft may be useful in open reduction and screw fixation via the Ollier approach for displaced intra-articular calcaneal fracture with a bony defect after reduction of collapsed posterior facet fragment. This graft can contribute to the stable reduction via a small approach, even without a plate.

• Journal of information and communication convergence engineering
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• v.13 no.2
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• pp.132-138
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• 2015

Enlarging the horizontal viewing angle is an important feature of integral imaging monitors. Thus far, the horizontal viewing angle has been enlarged in different ways, such as by changing the size of the elemental images or by tilting the lens array in the capture and reconstruction stages. However, these methods are limited by the microlenses used in the capture stage and by the fact that the images obtained cannot be easily projected into different displays. In this study, we upgrade our previously reported method, called SPOC 2.0. In particular, our new approach, which can be called SPOC 2.1, enlarges the viewing angle by increasing the density of the elemental images in the horizontal direction and by an appropriate application of our transformation and reshape algorithm. To illustrate our approach, we have calculated some high-viewing angle elemental images and displayed them on an integral imaging monitor.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.5
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• pp.85-93
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• 1994

We have studied the effect of channel and/or spacing chirpings on the near field and near field intensity patterns, modal gains and radiation angles of 6 supermodes in the index-guided laser arrays with 6 channels, on the basis of the coupled mode theory. The spacings between channels can be indenpendent parameters for control of the radiation angle. It is found that an asymmetrically v channel-chirped array has both a smaller radiation angle and better supermode discrimination characteristics than a uniform array. Comparing two approaches for enhancing modal stability in point of supermode discrimination characteristics, approach I which increases the coupling cofficient between the outer-most waveguides at each end of an otherwise uniform array, has superior discrimination characteristics to the approach II which increases the propagation constant for the end elements with the same coupling between neighbor elements. Approach III which has a narrower spacing between the outer-most waveguides at one end and a wider channel width of the outer-most waveguide at another end, gets a narrower radiation angle than the approach I and good supermode discrimination characteristics by applying optimized gain profiles.

• Structural Engineering and Mechanics
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• v.73 no.5
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• pp.515-527
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• 2020

This paper presents a stress field approach for the shear capacity of stirrup-reinforced concrete beams that explicitly incorporates the contribution of principal tensile stresses in concrete. This formulation represents an extension of the variable strut inclination method adopted in the Eurocode 2. In this model, the stress fields in web concrete consist of principal compressive stresses inclined at an angle θ combined with principal tensile stresses oriented along a direction orthogonal to the former (the latter being typically neglected in other formulations). Three different failure mechanisms are identified, from which the strut inclination angle and the corresponding shear strength are determined through equilibrium principles and the static theorem of limit analysis, similar to the EC-2 approach. It is demonstrated that incorporating the contribution of principal tensile stresses of concrete slightly increases the ultimate inclination angle of the compression struts as well as the shear capacity of reinforced concrete beams. The proposed stress field approach improves the prediction of the shear strength in comparison with the Eurocode 2 model, in terms of both accuracy (mean) and precision (CoV), as demonstrated by a broad comparison with more than 200 published experimental results from the literature.