• Journal of Computational Design and Engineering
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• 제1권1호
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• pp.48-54
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• 2014

In this paper, the authors propose a system for assisting mold designers of plastic parts. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with minimum undercuts. Since plastic parts are generally very thin, many rib features are placed on the inner side of the part to give sufficient structural strength. Our system extracts the rib features from the CAD model of the part, and determines the possible ejecting directions based on the geometric properties of the features. The system then selects the optimal direction with minimum undercuts. Possible ejecting directions are represented as discrete points on a Gauss map. Our new point distribution method for the Gauss map is based on the concept of the architectural geodesic dome. A hierarchical structure is also introduced in the point distribution, with a higher level "rough" Gauss map with rather sparse point distribution and another lower level "fine" Gauss map with much denser point distribution. A system is implemented and computational experiments are performed. Our system requires less than 10 seconds to determine the optimal ejecting direction of a CAD model with more than 1 million polygons.

• 대한두개안면성형외과학회지
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• 제21권2호
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• pp.77-79
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• 2020

• Archives of Plastic Surgery
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• 제45권6호
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• pp.578-582
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• 2018

Teratomas can occur in almost any region of the body and are the most common extragonadal germ cell childhood tumors. However, craniofacial teratomas are rare. Craniofacial teratomas can present unique features and cause significant functional and aesthetic concerns. There are complex lesions that can have components intra-cranially and extra-cranially. Therefore, their management requires significant multi-stage multidisciplinary surgical procedures. Herein, we present a case of craniofacial teratoma in a child with the phenotype of proboscis lateralis that highlights some of the pertinent point of the diagnosis and management of congenital neonatal teratomas.

• 대한두개안면성형외과학회지
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• 제16권2호
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• pp.92-95
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• 2015

A keratoacanthoma is a rapidly growing cutaneous tumor that spontaneously involutes in most instances. A giant keratoacanthoma is a rare variant and are characterized by lesions larger than 20 mm in diameter. We report a 56-year-old man with a rapidly growing tumor of the right cheek, which was diagnosed as keratoacanthoma. The mass was excised completely under general anesthesia, followed by Limberg flap for reconstruction. Intraoperative frozen section histology suggested the lesion to be a well-differentiated squamous cell carcinoma, whereas final histopathology was consistent with keratoacanthoma. We herein report the first case of a giant keratoacanthoma treated with surgical excision in Korea and discuss the clinical and histopathological features of keratoacanthoma, with a review of the literature.

• 대한두개안면성형외과학회지
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• 제22권3호
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• pp.154-156
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• 2021

Poroid hidradenoma has both features of hidradenoma and poroma. The histological hidradenoma framework consisting of solid and cystic components, and the presence of poroid and cuticular cells resembling a poroid neoplasm. Despite transforming into malignant neoplasm only in < 1% of cases, its histological characteristics may resemble those of malignant neoplasms. Although the risk of malignant transformation is very low, surgical excision is recommended to prevent growth and/or recurrence. To date, very few cases of poroid hidradenoma have been reported in the literature. Herein, we present a case of poroid hidradenoma on the scalp of a 74-year-old woman.

• 한국CDE학회논문집
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• 제5권2호
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• pp.196-205
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• 2000

This paper proposes a topology-based algorithm for recognizing the passage features using a concept of multi-face hole loop. The Multi-face hole loop is a concetpual hole loop that is formed over several connected faces. A passage feature is recognized in the proposed approach by two multi-face hole loops that constitute its enterance and exit. The algorithm proposed in this paper checks the connectivity of the two multi-face hole loops to recognize passage features. The total number of passage features in a part is calculated from Euler equation and is compared with the number of found passage features to decide when to terminate. To find all multi-face hole loops in a part, this paper proposes an algorithm for finding all combinations of connected faces. The edge convexity is used to judge the validity of multi-face hole loops. By using the algorithm proposed in this paper, the passage features could be recognized effectively. The approach proposed in this paper is illustrated with several example parts.

• 대한두개안면성형외과학회지
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• 제19권4호
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• pp.243-247
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• 2018

Vascular anomalies are disorders of the endothelium and surrounding cells that can affect the vasculature and involve any anatomical structure. The most common problem associated with vascular anomalies is psychological distress related to disfigurement as well as functional defects, as many lesions affect the head and neck. This article provides an overview of the current clinical features that distinguish the major types of vascular anomalies that affect the head and neck.

• Archives of Plastic Surgery
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• 제35권3호
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• pp.261-266
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• 2008

Purpose: The incidence of skin cancer is increasing throughout the world including Asian countries such as Korea. Still there are only limited reports of the clinical features of skin cancer in Korea, especially in the fields of plastic surgery. This study is to demonstrate the recent clinical trends of skin cancer and the treatment of skin cancer in Korea by analyzing a single institution's experience. Methods: During a 11-year period, 370 patients visited our department for the excision of skin cancer. Data of the patients such as histopathologic diagnosis, primary site of the tumor, age and sex of the patient, operative methods were reviewed retrospectively. Results: We had 370 patients, 215 men and 155 women. The ages ranged from 10 to 95 years with a mean of 58.8 years. A total of 143 patients were diagnosed as basal cell carcinoma, while 100 were malignant melanoma, 80 were squamous cell carcinoma, 17 were dermatofibrosarcoma protuberans, and 30 were other miscellaneous skin cancers. Local flaps were the most frequently used reconstructive method after wide excision of the cancer, which was followed by primary closure, split-thickness skin graft, free flap and full-thickness skin graft. Conclusion: There was a gradual increase in the incidence of skin cancer after the year 2000. Basal cell carcinoma had the highest incidence which frequently involved the sun-exposed regions in the old ages. Malignant melanoma showed a relatively high incidence compared with other previous studies in Korea. The extremities were the most frequent location for malignant melanoma. Clinical features of other various skin cancers were also reported in this study. The reconstructive method highly depends on the primary site of the cancer, while local flaps were the mostly used operative technique.

• 대한두개안면성형외과학회지
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• 제11권2호
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• pp.69-72
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• 2010

Purpose: All masks are created by craftspeople. Accordingly, most masks are generally predictable in dimensions, and the portraitures usually depict the faces and heads of humans. The authors found some masks representing the features of facial asymmetry, such as hemifacial microsomia and rerely lateral facial cleft. Methods: Reviewing the legends of wearing masks with a medley of grotesque features, the authors could deduce the tone of society in those days. Results: A mask, 'crooked mouth', of Native Americans shows typical lineament of hemifacial microsomia. The deformity of the face was legendarily regarded as resulting from trauma caused by either 'one's fault' or a 'curse of God'. 'Grandmother' mask, used in the Korean masque dance of the Kosung province and Sooyoung province also shows the typical features of hemifacial microsomia which represent the old, deserted wife. 'Kori sanni yakka' mask in Sri Lanka, shows the facial asymmetry. In the legend, the child who became demon captured humans and caused illness through wind, phlegm, and bile to revenge on his father who killed his mother by deception of her maid. Conclusion: The authors presume that the victims of severe facial asymmetry were treated contemptuously at that time.

• 대한기계학회논문집A
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• 제28권6호
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• pp.826-837
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• 2004

Rotational molding is a plastics processing technique that is ideally suited to producing relatively large, hollow, seamless parts which are partially or totally enclosed. Designers of plastic parts turn to rotational molding to produce small or large parts of unusual shape that cannot be produced as one piece by other processes, e.g., blow molding and thermoforming. In this paper, in order to enhance the quality of rotational molding plastic products, 1) surface features for the plastic products are characterized by using an image analysis system, 2) maximum tensile strength for the plastic products that are made of materials that consist of Samsung-Atofina R90lU, pigments and two different kinds of calcium carbonate (OMYA CaCO$_3$) is measured and compared with each other by using an Instron universal testing machine, 3) thickness for the plastic products is non-destructively measured to investigate the quality of the plastic products by using an A-scan ultrasonic tester.