• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.635-640
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• 1996

A thermo-elastic system in the production machine has highly nonlinear dynamic characteristics. In general, the finite element method is utilized for accurate analysis. However, it requires large computing time. Thus, thermo-elastic systems are usuallymodeled as electric and fluid system using lumped para,eter. In this paper. we propose the bondgraph model and transient simulation methodology of thermo-elastic system in consideration of various boundary and joint contact conditions. Consequently, the proposed method ensures a possibility of its on-line compensation about undesirable phenomena by using real time estimate process and electronic cooling device for thermal appropriate behavior. Thermo-elastic model consisting of bush and shaft including contact condition is presented.

• Journal of Drive and Control
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• v.16 no.4
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• pp.9-15
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• 2019

Bucket trajectory is crucial regarding precision work with an excavator. In general, the bucket trajectory deviation is determined by the machining deviation of the frame, driving deviation of the driving hydraulic cylinder, clearance in the joints, and deformation of the structure. This paper investigated the relationship between the respective clearance in joints and the trajectory deviation of the bucket at the finishing work of the ditching for a 20-ton excavator. As a result, the larger the clearance, the larger deviation is increased at trajectory. However, it was found that the deviation of the rotation angle and displacement of the bucket was limited and the size of clearance does not affect closely on the contact angle of the pin shaft.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.4
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• pp.610-618
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• 2001

Pantograph, which collects current from cartenary system, is one of the important parts of high-speed train. Kinematic analysis is one of the key technologies for pantograph design and includes joint trajectories, reaction forces, and the required moment of main shaft calculations. The kinematic analysis, however, is very complex and time-consuming process. In this study PC based pantograph kinematic analysis software using graphical user interface tool was developed for the easy evaluations of kinematic characteristics necessary in pantograph design process.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1452-1459
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• 2010

Application of long-span bridge, which is affected by parameters such as span length, shoe boundary condition, track property and stiffness of superstructure and substructure etc., can vary. Especially, by CWR aspects of the axial force, that can be less constraints of construction depending on whether the application of rail expansion joint(REJ), which has disadvantaged in terms of maintenance. In this study, it was performed parameter study for multiple variables (shaft length, the upper and lower cross-section characteristics, track characteristics, etc.) in terms of CWR aspects. Structure-rail interaction analysis was applied to the typical simple span PSC Box and 3 span continuous bridge Extradosed Bridge(50m+80m+50m) excluding REJ. If you set the boundary e of variables for long-span railway bridge excluding REJ through the this study, when designing future is expected to be able to useful.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1894-1899
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• 2000

The Roadway caused through Power Train engine vibration and bad ride comfort. It is very important to analyze the vibratory characteristics. The mathematical models on the Power Train, which is composed of engine-/transmission block, universal joint shaft, differential, rear axle arm and wheels, are developed and is verified by the experiments. This Paper describes the coupling influence occurred through a complete drive system for the power train. Dies study is carried out computationally with a calculation program and experimentally with the aid of the mode analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.629-640
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• 2008

South anchorage(AN1, Myodo side) of supension bridge between Myodo and Gwangyang is designed as rock anchorage with 36m anchor length using the resistance of rock mass in Myodo. Checking the overall stability of the anchorage, we considered rock joints, bedding planes, fault zones and condition of rock structure in situ by analysis results for photo-lineaments, aerial photograph interpretation and drill-hole logs are considered. This anchorage consists of an access shaft, adit, and the upper and lower concrete bearing plate to introduce pre-stressing force into rock mass.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.88-93
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• 1999

This paper presents the experimental examinations and statistical quantitative analysis of the correlation between the cumulative counts of acoustic emission(AE) during plastic deformation periods of the welding and the tensile strength and other properties of the bar-to-bar welded joints of O.D. 16mm shaft(SM40C) as well as the various welding variables. And this is a new approach which attempts finally to develop real-time quality monitoring system for friction welding. The results lead to a practical possibility of real-time quality control more than 100% joint efficiency showing good weld with no micro structural defects.

• Journal of Korean Foot and Ankle Society
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• v.22 no.4
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• pp.156-160
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• 2018

Purpose: Chronic tophaceous gout is a painful and disabling inflammatory disease. Surgical treatment for chronic tophaceous gout is very difficult with many complications. This study evaluated the efficacy of shortening scarf osteotomy on the treatment of chronic tophaceous gout in the 1st metatarso-phalangeal (MTP) joint. Materials and Methods: From January 2006 to December 2015, 14 patients (19 cases) who underwent axial shortening scarf osteotomy for chronic tophaceous gout were reviewed. All patients were male. The average age at the time of surgery was 59.6 years (42~66 years). The minimum follow-up was 24 months. Total removal of the tophi mass with the adhered medial capsule of the 1st MTP joint was attempted. Axial shortening scarf osteotomy was done on the 1st metatarsal shaft. The visual analogue scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot score was assessed preoperatively and postoperatively. The range of motion (ROM) of the 1st MTP joint was also compared pre- and postoperatively. Results: The average size of the extracted tophaceous mass was 32 mm. The mean amount of the length of metatarsal shortening was 4.9 mm. The mean ROM of the 1st MTP joint was improved from $30.4^{\circ}$ to $62.3^{\circ}$. The mean AOFAS forefoot score improved from 51.4 to 86.6 points. The mean VAS for pain improved from 4.6 to 0.3 points. Conclusion: The axial shortening scarf osteotomy used on chronic tophaceous gout could reconstruct the 1st MTP joint with an improved ROM and was free of pain. Axial shortening scarf osteotomy is suggested as a useful and effective method for the treatment of chronic tophaceous gout.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.1
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• pp.45-51
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• 1995

The incidence of metastatic bony lesion has been increased recently, with the advanced therapeutic modalities of malignant tumors. The purpose of this study was to evaluate the effectiveness of surgical treatment in impending or established pathologic fractures due to metastasis in extremity. From 1981 to 1992, thirty two patients who had established or impending pathologic fractures in extremity had been treated surgically. The locations of metastasis, were lower extremity in 24 cases(femsral head and neck;5, intertrochanteric;7, subtrochanteric;8, femoral shaft;4) and upper extremity in 8 cases(proximal humerus;2, humoral shaft;6). The method of surgery was excision of tumor mass and rigid internal fixation to allow immediate mobilization, except 2 cases of amputation. The results were analysed by two criteria. The first was the grade of performance status that was made by modification of Functional Classification of New York Heart Association. The second was the degree of pain relief. The performance status was improved at least one grade in all patients and the mean improvement was 1.7 grades. The satisfactory pain relief was achieved in 81% of patients. Postoperatively, most of the patients had only slight to moderate limitation of physical activities and they became comfortable at rest and ordinary activities. The solitary metastatic lesions showed better pain relief(92%) than multiple metastasis(75%). The curative surgery was done in 3 cases, and they showed more than 24 months of disease-free survival.

• The Journal of the Korean bone and joint tumor society
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• v.3 no.2
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• pp.112-118
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• 1997

Multicentric chondrosarcoma other than the mesenchymal subtype is rare separate entity. We experienced a case with nonmonomelic synchronous multicentric chondrosarcoma without any preexisting lesions of Oilier's disease or Maffucci's syndrome. To our knowledge, there was no report of synchronous nonmonomelic multicentric chondrosarcoma. A thirty-three year old man had right distal thigh pain of one and half year. Bone scan showed hot lesions on medial condyle of right femur and shaft of left femur. Plain X-ray showed osteolytic lesion on right femur and slight cortical thickening and calcific lesion was observed on left femoral shaft. Curettage and bone cement filling was done on both lesions. The pathology reports were grade I chondrosarcoma on both side of femur. At one month from operation, pathologic fracture of left femur occurred on bone cement-host bone junction. Conservative treatment and radiotherapy of 60Gy was done. At 8 months from operation, nonunion was evident. Segmental resection of left femur with contralateral fibula graft and second look operation on right condyle lesion were done. At 6 months from revision, fracture occurred at host-graft bone junction. We removed previous hardware and applied long DCP and massive autogenous bone graft. Afterwards, the patient looks good and union was progressing. But at 4 years from last operation, hypertrophic nonunion occurred. Another revision was done with condylar plate and bone graft and now he is well without any sign of local recurrence or metastasis.