• Journal of the Korean Arthroscopy Society
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• v.13 no.2
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• pp.183-187
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• 2009

Purpose: We describe a new and simple technique for arthroscopic fixation of tibial intercondylar eminence avulsion fracture using bioabsorbable pins in skeletally immature patients. Operative Technique: Diagnostic knee arthroscopy is performed using anterolateral and anteromedial portals. Fracture debris and blood clot are debrided to expose the injured site well. The fragment is reduced with the probe and fixed temporarily with a 1.1-mm diameter K-wire that is inserted percutaneously from the anterosuperior aspect of the knee joint. The drill guide is introduced into the joint and the fragment is secured by bioabsorbable, poly-p-dioxanone 1.3-mm pins inserted from different angles. The pins are 40 mm in length. The knee is placed in a long leg cast in extension for 4 weeks to assure that full extension is obtained. Conclusion: Arthroscopic fixation of an tibial intercondylar eminence avulsion fracture using bioabsorbable pins is not a technically demanding, suitable method that ensures fracture healing and restores the stability of the joint.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3442-3447
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• 2014

A simple method to evaluate the hygroscopic characteristics of polymer of microelectronic plastic package is suggested. To evaluate the characteristics, specimens were prepared, and the internally absorbed moisture masses were measured as a function of the absorbing time and calculated numerically. The hygroscopic pressure ratio was calculated by heat transfer analysis supported by commercial FEM code because the hygroscopic diffusion equation has the same form as the heat transfer equation. The moisture masses were then summed by the self developed code. The nonconductive polymers had quite different characteristics for the different lots, even though they were the same products. The absorbed moisture mass variations were calculated for several different characteristics, and the optimal curve of the mass variation close to experimental data was selected, whose solubility and diffusivity were affected by the hygroscopic characteristics of the material. The method can be useful in the industrial fields to quickly characterize the polymer material of the semiconductor package because the fast correspondence is normally required in industry. The weight changes in the aluminum-nonconductive-polymer joint due to moisture absorption were measured. The deformed system was also measured using the Moire Interferometry system and compared with the results of finite element analysis.

• Smart Media Journal
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• v.1 no.2
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• pp.40-46
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• 2012

In this paper, we describe interactive contents which is used the result of the inputted interface recognizing vision-based body gesture. Because the content uses the imp which is the common culture as the subject in Asia, we can enjoy it with culture familiarity. And also since the player can use their own gesture to fight with the imp in the game, they are naturally absorbed in the game. And the users can choose the multiple endings of the contents in the end of the scenario. In the part of the gesture recognition, KINECT is used to obtain the three-dimensional coordinates of each joint of the limb to capture the static pose of the actions. The vision-based 3D human pose recognition technology is used to method for convey human gesture in HCI(Human-Computer Interaction). 2D pose model based recognition method recognizes simple 2D human pose in particular environment On the other hand, 3D pose model which describes 3D human body skeletal structure can recognize more complex 3D pose than 2D pose model in because it can use joint angle and shape information of body part Because gestures can be presented through sequential static poses, we recognize the gestures which are configured poses by using HMM In this paper, we describe the interactive content which is used as input interface by using gesture recognition result. So, we can control the contents using only user's gestures naturally. And we intended to improve the immersion and the interest by using the imp who is used real-time interaction with user.

• Archives of Craniofacial Surgery
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• v.10 no.2
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• pp.131-134
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• 2009

Purpose: Mandible fractures are common in maxillofacial trauma and the incidence of condylar fracture is high. The management of mandibular condylar fracture continues to be controversial. Conservative treatment of it may lead to complications such as asymmetry, malocclusion, temporomandibular joint dysfunction. Moreover, open reduction can cause facial nerve injury, parotid gland injury, scarring and hematoma formation. We present a case of mandibular condylar fracture that was treated by manual reduction without incision under C-arm fluoroscopy. Methods: A 76-year-old female was admitted due to left side mandibular condylar fracture that required surgical intervention. Because of her age, history of diabetes mellitus, hypertension, she underwent closed manual reduction under general anesthesia. We adopted C-arm fluoroscopy as a method of identifying the fracture site and a evaluation of reduction state. C-arm fluoroscopy was set up like modified Towne's view. Results: The reduction was successful and didn't result in any complications that could occur in open reduction-facial nerve injury, infection, parotid gland injury, hematoma, avascular necrosis. The mandibular-maxillary fixations were removed after 4 weeks and patients were could open 3.5 cm after 6 weeks with physical therapy. Conclusion: We tried closed manual reduction of mandibular condylar fracture due to high risk of complication using C-arm fluoroscopy and did achieve anatomic reduction with avoiding open incision. This is simple, effective, reversible, time saving and fairly attemptable method in condylar fracture cases before open reduction.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1911-1919
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• 2012

In this paper, we focus on a robotic sealing process in which three robots are used. Each robot can be considered as a 7 axis redundant robot of which the first joint is prismatic and the last 6 joints are revolute. In the factory floor, robot path planning is not a simple problem and is not automated. They need experienced operators who can operate robots by teaching and playing back fashion. However, the robotic sealing process is well organized so the relative positions and orientations of the objects in the floor and robot paths are all pre-determined. Therefore by adopting robotic theory, we can optimally plan robot pathes without using teaching. In this paper, we analyze the sealing robot by using redundant manipulator theory and propose three different methods for path planning. For sealing paths outside of a car body, we propose two methods. The first one is resolving redundancy by using pseudo-inverse of Jacobian and the second one is by using weighted pseudo-inverse of Jacobian. The former is optimal in the sense of energy and the latter is optimal in the sense of manipulability. For sealing paths inside of a car body, we must consider collision avoidance so we propose a performance index for that purpose and a method for optimizing that performance index. We show by simulation that the proposed method can avoid collision with faithfully following the given end effector path.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.455-462
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• 2016

Recently, followed by rapid growth of robotics field, multi-linkage mechanism which can even pass by rough road is getting lots of attention. In this paper, I focused on Jansen mechanism. It's a kinematics object which is named after Dutch artist Theo jansen. Jansen mechanism embraces structure and mechanism which creates locomotion with the combination of the power and simple structure. Theo jansen suggests a 'Holy number'. It's an ideal ratio of leg components length. However, if there's desired gait locomotion, you have to adjust the ratio and the length. But even slight change of the length could cause a big change at the end-point. To solve this problem, I suggest a reverse engineering method to get a ratio of each links by nonlinear optimization with pre-set desired trajectory. First, we converted a movement of the joint of Jansen mechanism to vectors by kinematics analysis of multi-linkage structure. And we showed the trajectory at the end-point. After that, we set desired trajectory which we found most ideal. Then we got the length of the leg components which draws a trajectory as same as trajectory we set, using Multi-objective genetic algorithm toolbox in MATLAB. Result is verified by Edison designer and mSketch. And we analyzed if it could pass through the obstruction which is set dynamically.

• Structural Engineering and Mechanics
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• v.71 no.1
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• pp.57-63
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• 2019

During the last two decades, much joint research regarding vibration based methods has been done, leading to developing various algorithms and techniques. These algorithms and techniques can be divided into modal methods and signal methods. Although modal methods have been widely used for health monitoring and damage detection, signal methods due to higher efficiency have received considerable attention in various fields, including aerospace, mechanical and civil engineering. Signal-based methods are derived directly from the recorded responses through signal processing algorithms to detect damage. According to different signal processing techniques, signal-based methods can be divided into three categories including time domain methods, frequency domain methods, and time-frequency domain methods. The frequency domain methods are well-known and interest in using them has increased in recent years. To determine dynamic behaviours, to identify systems and to detect damages of bridges, different methods and algorithms have been proposed by researchers. In this study, a new algorithm to detect seismic damage in the bridge's piers is suggested. To evaluate the algorithm, an analytical model of a bridge with simple spans is used. Based on the algorithm, before and after damage, the bridge is excited by a sine force, and the piers' responses are measured. The dynamic specifications of the bridge are extracted by Power Spectral Density function. In addition, the Least Square Method is used to detect damage in the bridge's piers. The results indicate that the proposed algorithm can identify the seismic damage effectively. The algorithm is output-only method and measuring the excitation force is not needed. Moreover, the proposed approach does not need numerical models.

• Steel and Composite Structures
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• v.42 no.1
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• pp.91-106
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• 2022

Concrete-filled square stainless steel tubes (CFSSST), which possess relatively large flexural stiffness, high corrosion resistance and require simple joint configurations and low maintenance cost, have a great potential in constructional applications. Despite that the use of stainless steel may result in high initial cost compared to their conventional carbon steel counterparts, the whole-life cost of CFSSST is however considered to be lower, which offers a competitive choice in engineering practice. In this paper, a comprehensive experimental and numerical program on 24 CFSSST stub column specimens, including 3 austenitic and 3 duplex stainless steel square hollow section (SHS) stub columns and 9 austenitic and 9 duplex CFSSST stub columns, has been carried out. Finite element (FE) models were developed to be used in parametric analysis to investigate the influence of the tube thickness and concrete strength on the ultimate capacities more accurately. Comparisons of the experimental and numerical results with the predictions made by design guides ACI 318, ANSI/AISC 360, Eurocode 4 and GB 50936 have been performed. It was found that these design methods generally give conservative predictions to the ultimate capacities of CFSSST stub columns. Improved calculation methods, developed based on the Continuous Strength Method, have been proposed to provide more accurate estimations of the ultimate resistances of CFSSST stub columns. The suitability of these proposals has been validated by comparison with the test results, where a good agreement between the predictions and the test results have been achieved.

• The Journal of the Korean bone and joint tumor society
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• v.12 no.1
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• pp.23-29
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• 2006

Purpose: To evaluate the effectiveness of steroid injection for treatment of simple bone cyst in adults. Materials and Methods: 11 patients who were able to be followed up from February 1998 to February 2003. These lesions were attained by needle aspiration or trepanation and 80 mg to 200 mg of Depo-medrol (methylprednisolone acetate, Shin Poong Pharm. Co., Korea) was injected. The follow-up roentgenograms were done every 2 weeks, and if there were no evidence of recovery, re-injection was done 8 weeks later. Injection has done maximally 5 times, and we evaluated the result with modified Neer, Pentimalli, Scaglietti and Sandra classification. Results: There were no cases in which one Injection was enough for full recovery, and 3 cases after 2 injections, 3 cases after 3 injections, 2 case after 5 injections had good result. but 2 cases after more than 5 injections did not show improvements and are currently under observation. One case showed a increase in size of the bone cyst after 2 injections of steroid and underwent curettage and autogenous bone graft. Overall outcomes by Pentimalli classification were good in One case, fair in 7 cases and poor in 3 cases at final follow-up. Conclusion: Local injection of steroids is effective method in adults and can be considered as a first line treatment modality.

• Journal of the Korean Arthroscopy Society
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• v.9 no.2
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• pp.201-205
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• 2005

Purpose: The purpose of this study is to evaluate the result of arthroscopic excision of painful Os subtibiale and Os subfibulare. Materials and Methods: Sixteen patients who had accessory bone in the ankle joint were treated by arthroscopy. Os subtibiale was four cases and os subfibulare twelve. The average follow-up period was 9 months$(range:6{\sim}42months)$. All patients were evaluated clinically with physical examination and radiologically with simple X-ray and for further evaluation, eight with bone scan, three with computed tomography and twelve with magnetic resonance image. We estimated the result of resection with Ogilvie-Harris's criteria. Results: All parameters of subjective and functional evaluation were improved with statistical significance(p<0.05). At final evaluation, eight patients still complained of mild pain and among them, three patients for synovitis, three for tendinitis on MRI and two for incomplete resection. Conclusion: The arthroscopic resection is a very effective method for painful os subtibiale and subfibulare using small incisions and for treatment of associated lesion. The preoperative radiological evaluation is essential and magnetic resornance image is useful for detecting of associated lesion.