• Journal of Welding and Joining
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• v.34 no.2
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• pp.59-66
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• 2016

The Gas Metal Arc(GMA) welding, called Metal Inert Gas(MIG) welding, has been an important component in manufacturing industries. A key technology for robotic welding processes is seam tracking system, which is critical to improve the welding quality and welding capacities. The objectives of this study were to develop the intelligent and cost-effective algorithms for image processing in GMA welding which based on the laser vision sensor. Welding images were captured from the CCD camera and then processed by the proposed algorithm to track the weld joint location. The proposed algorithms that commonly used at the present stage were verified and compared to obtain the optimal one for each step in image processing. Finally, validity of the proposed algorithms was examined by using weld seam images obtained with different welding environments for image processing. The results proved that the proposed algorithm was quite excellent in getting rid of the variable noises to extract the feature points and centerline for seam tracking in GMA welding and could be employed for general industrial application.

• Steel and Composite Structures
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• v.23 no.6
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• pp.727-736
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• 2017

The application of carbon fiber reinforced polymer (CFRP) in steel structures primarily includes two categories, i.e., the bond-critical application and the contact-critical application. Debonding failure and buckling failure are the main failure modes for these two applications. Conventional electrometric techniques may not provide precise results because of the limitations associated with single-point contact measurements. A nondestructive full-field measurement technique is a valuable alternative to conventional methods. In this study, the digital image correlation (DIC) technique was adopted to investigate the bond behavior and buckling behavior of CFRP-steel composite members. The CFRP-to-steel bonded joint and the CFRP-strengthened square hollow section (SHS) steel column were tested to verify the suitability of the DIC technique. The stereo-DIC technique was utilized to measure continuous deformation. The bond-slip relationship of the CFRP-to-steel interface was derived using the DIC data. Additionally, a multi-camera DIC system consisting of four stereo-DIC subsystems was proposed and applied to the compressive test of CFRP-strengthened SHS steel column. The precise buckling location and CFRP delamination of the CFRP-strengthened SHS steel column were identified. The experimental results confirm that the stereo-DIC technique can provide effective measurements for investigating the behaviors of CFRP-steel composite members.

• Geophysics and Geophysical Exploration
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• v.19 no.2
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• pp.97-104
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• 2016

Small to large earthquakes have been reported in Gyeongju and its vicinity in southeast Korea during historical period as well as instrumental observation period. We identified and located more than 300 earthquakes that occurred between January 2010 and December 2014 in a $20km{\times}30km$ area, but were unreported because of their small magnitudes. We used the Joint Hypocenter Determination (JHD) method to minimize the influence of the differences between the actual earth structure and 1-D velocity model for earthquake locations. The potential relationship between the previously reported Quaternary faults and the earthquake hypocenters was investigated. Many micro-earthquakes were found to be located in the southern segment of the Yeonil Tectonic Line, the Seokup fault, and the Waup basin boundary faults.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.679-687
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• 2008

The fatigue life of ship structure under cyclic loading condition is made up of crack initiation and propagation stages. For a welding member in ship structure, the fatigue crack propagation life is more important than the fatigue crack initiation life. To calculate precisely the fatigue crack propagation life at the critical welding location, the knowledge of the residual stress sensitivity on the fatigue strength is necessary. In this study, thermo elastic-plastic analysis was conducted in order to examine the effect of residual stress on the fatigue crack propagation life. Also the fatigue crack propagation lives considering residual stress were calculated using fatigue crack growth code, AFGROW, on the basis of fracture mechanics. AFGROW is widely used for fatigue crack growth predictions under constant and variable amplitude loading. The reliability of AFGROW on the fatigue of ship structure was confirmed by the comparison of the estimated results with the fatigue propagation test results.

• The Journal of the Korean bone and joint tumor society
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• v.4 no.1
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• pp.30-36
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• 1998

Squamous cell carcinoma is a neglected disease entity in orthopedic oncology. The purpose of this study was to analyze overall survival and the role of surgery on survival and to evaluate the significance of possible prognostic factors. From Oct, 1986 to Aug, 1996, 57 patients were enlisted and 42 patients ere eligible. Inclusion criteria included more than one year follow-up and no distant metastasis at the first visit. Staging and survival followed AJC classification and Kaplan-Meier plot. Stage II included 17 cases and stage III, 25 cases. Thirty-eight patients underwent operations, chemotherapy, and/or radiotherapy, and the remaining four had operations only. The chemotherapeutic regimen was adriamycin-cisplatin. The average follow-up period was 45 months. The ten-year actuarial survival rate of whole patients was 65.4%. Location of primary lesion, stage, pathologic grading, and intensity of chemotherapy in the same stage showed a significant difference in survival. Nine out of 42 patients had local recurrence. Seven patients had inadequate wide margins and two had intralesional margins. Average period of recurrence from operation was 13(4-35)months. The operation itself had no impact on survival but a surgical margin of no less than 3cm from the lesion was important for local control. Pathological grade and staging were significant variables for long term survival. Acral lesion had a significantly higher chance of regional and distant metastasis but actual survival showed no difference. In stage II, aggressive chemotherapy could delay or reduce the chance of regional or distant metastasis.

• The Journal of the Korean bone and joint tumor society
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• v.15 no.1
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• pp.65-68
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• 2009

Proliferating trichilemmal tumor(PTT) is a rare neoplasm derived from the outer root sheath of the hair follicle. Malignant transformation is rare, but abrupt enlargement of size, infiltrative growth, and non-scalp location are suggestive of malignant PTT. Histopathologic characteristics of malignant PTT are nuclear atypia, pleomorphism, and mitotic figures. Recurrence and metastasis have been documented in malignant PTT. Wide resection of the tumor with the normal tissue and accurate follow-up is the treatment of choice of the both malignant and benign PTT. We report a 51-year-old man with the mass on right 5th finger distal phalanx for 7 years. The tumor was excised with middle phalangiectomy, and based on the histopathologic findings of the tumor, this case was diagnosed as mailignant PTT. We cannot detect recurrence and metastasis because the patient was lost to follow-up.

• Journal of Korean Foot and Ankle Society
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• v.18 no.4
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• pp.153-158
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• 2014

Purpose: The objective of this study was to examine the clinical results and effectiveness of resection arthroplasty for correction of lesser toe deformity. Materials and Methods: From January 2000 to November 2012, 92 cases of resection arthroplasty for lesser toe deformity were reviewed. Hammer toe was the most common type of deformity, accounting for 44 toes (33 patients). Hallux valgus was the most common comorbid illness. Second toe was the most commonly affected toe and proximal interphalangeal joint was the most common location of resection arthroplasty (69 toes, 75.0%). We also analyzed the alignment of phalanges using the last follow-up weight bearing radiographic image. The analysis included clinical evaluation with American Orthopaedic Foot and Ankle Society (AOFAS) score as well as subjective satisfaction. Results: Flexor tenotomy (19 cases) was the most common combined surgery. Floating toe (4 cases) was the most common complication. The last follow-up alignment of phalanges was better than good in 71 toes (77.2%) in anteroposterior view and in 69 toes (75.0%) in lateral view. Sixty one cases (85.9%) resulted in better satisfaction than 'good' and the final average AOFAS score was 87.4. Conclusion: Resection arthroplasty is a valuable surgical option for treatment of lesser toe deformity, with high patient satisfaction, easy surgical technique and remarkable correction of deformity.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.1-9
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• 2012

We consider a receiving node, located at the origin, and a Poisson point process (PPP) that models the locations of the desired transmitter as well as the interferers. Interference is known to be non-Gaussian in this scenario. The capacity bounds for additive non-Gaussian channels depend not only on the power of interference (i.e., up to second order statistics) but also on its entropy power which is influenced by higher order statistics as well. Therefore, a complete statistical characterization of interference is required to obtain the capacity bounds. While the statistics of sum of signal and interference is known in closed form, the statistics of interference highly depends on the location of the desired transmitter. In this paper, we show that there is a tradeoff between entropy power of interference on the one hand and signal and interference power on the other hand which have conflicting effects on the channel capacity. We obtain closed form results for the cumulants of the interference, when the desired transmitter node is an arbitrary neighbor of the receiver. We show that to find the cumulants, joint statistics of distances in the PPP will be required which we obtain in closed form. Using the cumulants, we approximate the interference entropy power and obtain bounds on the capacity of the channel between an arbitrary transmitter and the receiver. Our results provide insight and shed light on the capacity of links in a Poisson network. In particular, we show that, in a Poisson network, the closest hop is not necessarily the highest capacity link.

• Journal of Korea Game Society
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• v.13 no.1
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• pp.19-30
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• 2013

This paper proposes a serious game for rehabilitation training targeting old persons and patients for rehabilitation. The serious game suggested for rehabilitation training provides the whole body movement recognition-based interface using the 3D depth camera. When the user stands before the camera, it distinguishes the user from the background and then recognizes the user's whole body with 15 joints. By analyzing the changes of location and direction of each joint, it recognizes gestures needed for the game. The game contents consist of the games for upper limb training, lower limb training, whole body training, and balance training, and it was realized in both 2D and 3D games. The system suggested in this article works robustly even with the environmental changes using the 3D depth camera. Even with no separate device, the game recognizes the gestures only using the whole body movement, and this enhances the effect of rehabilitation.

• Journal of Information Management
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• v.29 no.1
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• pp.1-19
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• 1998

With development in computing and networking technologies, national supports and attention for building digital library, which is to overcome the limits of time and location in using information resources, is increasing. To accomplish the main goal of digital library that is to freely share and transfer information on network, the importance of standardization in developing electronic document is increasing. Now several tools to develop electronic document, which will be used in digital library, are developed for electronic document used on WWW. But none of them has absolute advantages to other formats. Those tools, that is, have comparative advantages and disadvantages for making electronic documents. Through reviewing features and analyzing comparative advantage and disadvantage of SGML, HTML, and PDF, which will be used to develop electronic documents in digital libraries, this study focuses on their comparative advantages and disadvantages. With doing it, this study propose relevant type of electronic document formats to the types of information resources.