• Steel and Composite Structures
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• v.26 no.5
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• pp.635-647
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• 2018

In order to improve the efficiency of the Reinforced Concrete, RC, structures against progressive collapse, this paper proposes a procedure using alternate path and specific local resistance method to resist progressive collapse in intermediate RC frame structures. Cap truss consists of multiple trusses above a suddenly removed structural element to restrain excessive collapse and provide an alternate path. Steel strut is used as a brace to resist compressive axial forces. It is similar to knee braces in the geometry, responsible for enhancing ductility and preventing shear force localization around the column. In this paper, column removals in the critical position at the first story of two 5 and 10-story regular buildings strengthened using steel strut or cap truss are studied. Based on nonlinear dynamic analysis results, steel strut can only decrease vertical displacement due to sudden removal of the column at the first story about 23%. Cap truss can reduce the average vertical displacement and column axial force transferred to adjacent columns for the studied buildings about 56% and 61%, respectively due to sudden removal of the column. In other words, using cap truss, the axial force in the removed column transfers through an alternate path to adjacent columns to prevent local or general failure or to delay the progressive collapse occurrence.

• The Journal of the Korean bone and joint tumor society
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• v.7 no.2
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• pp.73-79
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• 2001

Giant cell tumor is usually found around the knee joint, especially in the distal femur or proximal tibia. Despite being classified as benign, it has unusual biological behavior of local aggressiveness and tend to have severely destructive lesion and develop rare pulmonary metastasis. Therefore, when the patient is presented to the physician with an expansile lytic lesion of challenging clinicopathologic entity extending to subchondral bone, the physician faces up to difficulties in treatment. We report a case of 25 years old patient having recurrent giant cell tumor in the right distal femur which developed metastasis to lung. The primary bone lesion was treated with local curettage and fillings with methylmethacrylate, but when he returned to the hospital two years later, the recurrence had developed with lung metastasis.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.87-90
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• 2001

This paper presents a design of new type biped robot and dynamic walking simulation for this system. The robot is distinguished from other one by which has a parallel mechanism type trunk and lead-screw type actuators to drive the joints of the trunk, knee and ankle. The basic consideration on the design is that it is able to accommodate itself to human's daily environments without any other modification of around and also to operate its upper limbs more smoothly with a spine functional trunk. It is designed according to a human with about 130 cm height and about 30 kg weight. And it also is able to dynamically walk on an even ground. It has constructed with total 14 DOFs which have two legs, a hip, and a trunk. The joints of each leg and trunk are adopted with a parallel structure which has good kinematic characteristics and take light weight. To test of the capacity of joint actuators and to analysis of the dynamic properties of the biped robot, optimized trunk trajectory is determined by means of an approximated FFT method based on ZMP criteria, and dynamic simulation is performed using DADS with a 1.1 time/step velocity on the even ground during four steps.

• The Journal of the Korean bone and joint tumor society
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• v.18 no.1
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• pp.28-31
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• 2012

Baker's cyst is found as most frequent cystic mass around the knee occurring between medial head of gastrocnemius muscle and semimembranosus muscle. The proximal or posterolateral extension of the cyst had been rarely reported and the cyst into the surrounding muscular tissue extremely rare. Intramuscular Baker's cyst that we report was found between lateral head of gastrocnemius muscle and popliteus tendon, and then extended into the plantaris muscle. With review of the literature, we here report a very rare case of plantaris muscular extension of Baker's cyst.

• Journal of Korean Foot and Ankle Society
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• v.23 no.1
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• pp.35-38
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• 2019

Lipoma arborescens or synovial lipomatosis is a rare disorder that is characterized by mature fat infiltration of the hypertrophic synovial villi, most frequently affecting the supra-patellar pouch of the knee. This paper presents a case of lipoma arborescens of the ankle joint bilaterally in an adult patient with involvement of both the intra-articular synovium and the synovial sheath of the tendons around the ankle.

• Journal of the Korean Orthopaedic Association
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• v.54 no.2
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• pp.182-186
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• 2019

Giant cell tumor is a benign but locally aggressive tumor with common recurrence. Most cases occur around the knee joint. Giant cell tumor of the foot is rare and very few cases involving the first metatarsal have been reported. Its characteristics and treatment in adult patients remain unclear. This paper reports a case of recurrent giant cell tumor at the first metatarsal that was excised surgically and subsequently reconstructed with non-vascularized fibula graft.

• The Journal of the Korean bone and joint tumor society
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• v.7 no.2
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• pp.59-63
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• 2001

Chondosarcoma of the calcaneus in young child is extremely rare. A thirteen-year old male patient has suffered from right heel pain for several months before. Dominant gross feature was hard mass and swelling on one entire right heel, and increased density and calcification on entire calcaneus with cortical destruction, and calcific densities on soft tissues around calcaneus were seen on roentgenogram of right ankle. It was diagnosed to be chondrosarcoma by bone biopsy. It was treated by below knee amputation and chemotherapy, and no recur and distant metastsis during 12 months after operation.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.3 no.2
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• pp.69-73
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• 2010

Osteochondroma arising around the knee joint may sometimes be associated with vascular complication. Angiography is widely used to demonstrate the vascular complication, but it is invasive. Recently MR angiography is recommended as a non-invasive alternative, but it is very costly. We report a twenty-year-old man with popliteal arterial compression caused by osteochondroma who was diagnosed and assessed the surgical result by Doppler ultrasonography. And we also provide the usefulness of Doppler ultrasonography.

• Journal of computational fluids engineering
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• v.20 no.2
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• pp.61-66
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• 2015

In this study, an aero-acoustic analysis around pantograph of a high speed train is performed. Computational technique and grid system is validated with wind tunnel test result and unsteady acoustic pressure data are used for analyzing noise level of each part of pantograph. FLUENT is used for flow analysis and LES(Large Eddy Simulation) is applied for analyzing turbulent flow. For acoustic analysis, Ffowcs Williams-Hawkings(FW-H) acoustics model is used and it bring the aero-acoustic characteristic of pantograph. As the result, contact strip, knee, substructure of pantograph is confirmed as a main source of aero-acoustic noise and it is dealt in various frequencies. The result is expected to help building improved grid system.

• The Journal of the Korean bone and joint tumor society
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• v.7 no.2
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• pp.51-58
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• 2001

Purpose : In patients having malignant and aggressive bone tumors around knee joint requiring amputation, segmental resection and rotationplasty were performed and the clinical results were analyzed. Materials and Methods : Twenty-six patients underwent segmental resection and rotationplasty between February 1988 and June 1994, because limb salvage with tumor prosthesis after removal of tumor was impossible. The mean follow-up of malignant tumors was 57(6~120) months and the average age of patients was 21.4(5~37) years old. Out of 26 patients, there were 18 osteosarcoma(${\geq}$stage IIB), 2 synovial sarcoma, and 6 giant cell tumor. Results : Clinical results were evaluated by the Shriner's rating system. Four patients were excluded due to death or amputation and remaining 22 patients were included for assessment. Eighteen patients had excellent result, 3 good, and 1 fair. Range of motion of ankle joint was -11(dorsiflexion)~80(plantarflexion) degrees and daily walking activity with prosthesis was possible. Local recurrence developed in 2 patients and distant metastasis in 10. Early complications had 3 thrombosis and 1 sepsis, and late complications had 6 nonunion, 2 malrotation and 1 stiffness of ankle joint. Conclusion : Rotationplasty which is functionally excellent may serve as an effective partial limb salvage procedure, especially in patients less than 10 years old that lower extremity discrepancy or loosening tumor prosthesis due to enlargement of medullary cavity are anticipated or amputation is inevitable for wide resection margin.