• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.693-701
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• 2010

In this paper, it is proposed that an attitude and position estimation algorithm based on a stereo camera system for a helmet tracker. Stereo camera system consists of two CCD camera, a helmet, infrared LEDs and a frame grabber. Fifteen infrared LEDs are feature points which are used to determine the attitude and position of the helmet. These features are arranged in triangle pattern with different distance on the helmet. Vision-based the attitude and position algorithm consists of feature segmentation, projective reconstruction, model indexing and attitude estimation. In this paper, the attitude estimation algorithm using UQ (Unit Quaternion) is proposed. The UQ guarantee that the rotation matrix is a unitary matrix. The performance of presented algorithm is verified by simulation and experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.934-937
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• 2003

In this paper, authors use a stereo vision system based on the visual model of human and establish inexpensive method that recognizes moving distance using characteristic points around the robot. With the stereovision. the changes of the coordinate values of the characteristic points that are fixed around the robot are measured. Self-displacement and self-localization recognition system is proposed from coordination reconstruction with those changes. To evaluate the proposed system, several characteristic points that is made with a LED around the robot and two cheap USB PC cameras are used. The mobile robot measures the coordinate value of each characteristic point at its initial position. After moving, the robot measures the coordinate values of the characteristic points those are set at the initial position. The mobile robot compares the changes of these several coordinate values and converts transformation matrix from these coordinate changes. As a matrix of the amount and the direction of moving displacement of the mobile robot, the obtained transformation matrix represents self-displacement and self-localization by the environment.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.4
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• pp.86-94
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• 1993

In this study, a tentative decision-making matrix for village planning in reclaimed land was proposed. The evaluating conditions in the matrix are reclaimed farming acreage and distance. And the indexes for evaluation works are farming acreage required for increasing present farm size to target size in the base of, allowable commuting distance for farming from and effective controlling distance of each village. The village planning strategies are considered into four categories ; upkeep of present village scale, transfer of its superfluous farming acreage to a neighbouring village, enlargement of present village scale and new village construction in reclaimed land. As a case study, the proposed decision-making matrix was applied to 69 villages, which are contiguous to the potential farming area from reclamation works of Yongsan River Basin Comprehensive Development Project Phase Ill and so considered in this study as future farming villages there. From the application results, the following tactics for village planning may be proposed ; principally, upkeep or enlargement of present village scale, but, in an exceptional few cases of standard farming size being 3~5ha, new village construction of normal or satellite scale.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8A
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• pp.829-835
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• 2002

When finite length image signal is decomposed into M-band synthesized using M-band orthogonal wavelet transform, the boundary signal of image are not reconstructed perfectly. for boundary signals to be reconstructed perfectly, different type filter bank or technique is applied to them when the dimension of analysed is proposed. It can be designed using the singular value decomposition of boundary perfect reconstruction matrix which is obtained from paraunitary matrix which is obtained from paraunitary matrix. And it is also discussed to design the boundary filter bank for improving the coding performance when it is applied to subband coder. The proposed boundary filter bank shows 7% gains in PSNR compared with reflected method.

• Archives of Plastic Surgery
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• v.42 no.2
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• pp.194-200
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• 2015

Background Surgical site infections (SSIs) result in significant patient morbidity following immediate tissue expander breast reconstruction (ITEBR). This study determined a single institution's 30-day SSI rate and benchmarked it against that among national institutions participating in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). Methods Women who underwent ITEBR with/without acellular dermal matrix (ADM) were identified using the ACS-NSQIP database between 2005 and 2011. Patient characteristics associated with the 30-day SSI rate were determined, and differences in rates between our institution and the national database were assessed. Results 12,163 patients underwent ITEBR, including 263 at our institution. SSIs occurred in 416 (3.4%) patients nationwide excluding our institution, with lower rates observed at our institution (1.9%). Nationwide, SSIs were significantly more common in ITEBR patients with ADM (4.5%) compared to non-ADM patients (3.2%, P=0.005), and this trend was observed at our institution (2.1% vs. 1.6%, P=1.00). A multivariable analysis of all institutions identified age ${\geq}50$ years (odds ratio [OR], 1.4; confidence interval [CI], 1.1-1.7), body mass index ${\geq}30kg/m^2$ vs. < $25kg/m^2$ (OR, 3.4; CI, 2.6-4.5), and operative time >4.25 hours (OR, 1.9; CI, 1.5-2.4) as risk factors for SSIs. Our institutional SSI rate was lower than the nationwide rate (OR, 0.4; CI, 0.2-1.1), although this difference was not statistically significant (P=0.07). Conclusions The 30-day SSI rate at our institution in patients who underwent ITEBR was lower than the nation. SSIs occurred more frequently in procedures involving ADM both nationally and at our institution.

• Computers and Concrete
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• v.10 no.2
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• pp.135-147
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• 2012

At mesoscale, concrete is considered as a three-phase composite material consisting of the aggregate particles, the cement matrix and the interfacial transition zone (ITZ). The reconstruction of the internal structures for concrete composites requires the identification of the boundary of the aggregate particles and the cement matrix using digital imaging technology followed by post-processing through MATLAB. A parameter study covers the subsection transformation, median filter, and open and close operation of the digital image sample to obtain the optimal parameter for performing the image processing technology. The subsection transformation is performed using a grey histogram of the digital image samples with a threshold value of [120, 210] followed by median filtering with a $16{\times}16$ square module based on the dimensions of the aggregate particles and their internal impurity. We then select a "disk" tectonic structure with a specific radius, which performs open and close operations on the images. The edges of the aggregate particles (similar to the original digital images) are obtained using the canny edge detection method. The finite element model at mesoscale can be established using the proposed image processing technology. The location of the crack determined through the numerical method is identical to the experimental result, and the load-displacement curve determined through the numerical method is in close agreement with the experimental results. Comparisons of the numerical and experimental results show that the proposed image processing technology is highly effective in reconstructing the internal structures of concrete composites.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.2
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• pp.123-132
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• 2000

The field of maxillofacial prosthetics is concerned with the prosthetic reconstruction of missing head and neck tissue. Currently, facial prostheses are usually applied in cases of defects caused by the surgical removal of tumors or congenital defects. While silicone has been most widely used for the reconstruction of missing maxillofacial defects, it does not have ideal physical properties. Therefore, bonding a thin polyurethane sheet to silicone prostheses was recommended. In this case skin adhesives were used for the retention of maxillofacial prostheses. But retention of devices has always been problematic. The contributions of implants can be made to solve these problems. Implants have reduced the need for adhesive use, simplifying cleaning procedures and thus extending the life of the prostheses. For implant-retained prostheses, retentive matrix is necessary to hold attachments and/or magnets. The retentive matrix is usually fabricated with autopolymerizing acrylic resin or visible light- polymerized resin. The purpose of this study was to compare the adhesion-in-peel force of silicone adhesive to autopolymerizing acrylic resin and polyurethane sheet with two different surface textures : pumice polish only or retention groove, and three surface primers : Dow corning 1205 primer or Dow corning S-2260 primer or FactorII A-304 primer, and two polymerization methods : room temperature or dry heat oven. The t-peel bond strength of specimens was determined as described in ASTM Standard D1876-72. The results were statistically analyzed using the ANOVA test, multiple range test and t-test The results were as follows. 1. The t-peel bond strength of A-304 primer was the highest and statistically higher than that of S-2260(p<0.05). 2. The t-peel bond strength of specimens with retention groove was statistically higher than that of specimens polished with pumice(p<0.05). 3. The t-peel bond strength of specimens polymerized in dry heat oven was statistically higher than that of specimens in room temperature(p<0.01).

• Archives of Plastic Surgery
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• v.44 no.3
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• pp.234-237
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• 2017

Paraffinoma is a destructive complication of paraffin oil injection, usually associated with massive tissue destruction, thus requiring radical surgery and subsequent complex reconstruction. Although breast and penile paraffinomas have been widely described and their management is quite standardized, paraffinomas of the knee are still rare and only few case reports or small case series are available in the current literature. We describe the case of a 77-year-old man with a large paraffinoma of the right knee that occurred after self-injection of paraffin oil, 58 years before. He underwent wide surgical resection of the soft tissues overlying the knee and subsequent two-stage reconstruction by using acellular dermal matrix and, after 20 days, split-thickness skin grafts. Follow-up after 16 months showed no signs of skin ulcerations or inflammation, with an overall improvement in function. Even though conventional flap reconstructions may be still useful, the authors believe that acellular dermal matrices represent a safe, reliable, and less invasive alternative for challenging soft tissue reconstructions even in elderly patients with multiple medical problems.

• Journal of Chest Surgery
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• v.24 no.8
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• pp.802-806
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• 1991

Primary neoplasms of the ribs and sternum are rare. Most primary bony chest wall neoplasms are malignant, and chondrosarcoma is the most common malignancy in this location The etiology of chondrosarcoma is unknown. Definitive diagnosis of chondrosarcoma can only be made pathologically. The natural history of chest wall chondrosarcoma is one of slow growth and local recurrence. Most tumors of the sternum require wide resection and reconstruction procedures, with potentially serious postoperative problems. Advances in chest wall reconstruction primarily through refinement in muscle transposition and clarification of the functional anatomy and blood supply of trunk muscles, has resulted in a more aggressive resection of the these tumors . Recently we experienced a case with chondrosarcoma of the sternum. A 56 year-old man was admitted to our hospital due to painless, slowly enlarging mass at the left sternoclavicular junctional area. The chest radiograph strongly suggested an underlying cartilaginous neoplasm owing to the appearance of typical flocculent and curvilinear calcifications within the lesion. On CT of the chest, the tumor exhibited a scalloped or lobulated contour, hypodensity of the nonmineralized component in comparison to adjacent muscle, and characteristic stippled cartilaginous matrix mineralization, also typical for cartilaginous neoplasm. The patient underwent wide resection of the chest wall tumor include with a 2-3cm margin of normal tissue on all sides and the thoracic skeletal defect was reconstructed with polytetrafluoroethylene [Gore-Tex] soft-tissue patch. Soft tissue reconstructive procedure was done with the pectoralis major muscle transposition. The patient had an uneventful postoperative course and discharged without adjuvant treatment such as radiation and chemotherapy.

• Archives of Craniofacial Surgery
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• v.16 no.2
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• pp.80-83
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• 2015

We present reconstruction of a complicated scalp-dura defect using acellular human dermis and latissimus dorsi myocutaneous free flap. A 62-year-old female had previously undergone decompressive craniectomy for intracranial hemorrhage. The cranial bone flap was cryopreserved and restored to the original location subsequently, but necessitated removal for a methicillin-resistant Staphylococcal infection. However, the infectious nidus remained in a dermal substitute that was left over the cerebrum. Upon re-exploration, this material was removed, and frank pus was observed in the deep space just over the arachnoid layer. This was carefully irrigated, and the dural defect was closed with acellular dermal matrix in a watertight manner. The remaining scalp defect was covered using a free latissimus dorsi flap with anastomosis between the thoracodorsal and deep temporal arteries. The wound healed well without complications, and the scalp remained intact without any evidence of cerebrospinal fluid leak or continued infection.