• The Journal of the Korean bone and joint tumor society
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• v.13 no.2
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• pp.195-200
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• 2007

Dedifferentiated parosteal osteosarcoma is an uncommon variant of osteosarcoma. Dedifferentiation is known to be associated with a greater metastatic potential and a more rapid lethal clinical course. Thus recognition of dedifferentiation is important to establish the treatment strategy. But there may be few significant clinical clues to distinguish between dedifferentiated parosteal osteosarcoma and conventional one. A 29-year-old woman presented with 2-year history of discomfort and swelling in her proximal thigh. Examination showed a large, hard, non-mobile mass. Radiographs revealed a large ossified mass attached to the proximal femur. Diagnosis of parosteal osteosarcoma was established by MRI and needle biopsy. But she had a history of abrupt severe thigh pain and increased swelling before surgery. Follow up MRI showed enlargement of mass with invasion to muscle around tumor. The patient underwent an en-bloc resection of tumor and reconstruction. Histological examination showed parosteal sarcoma with dedifferentiation. The patient expired due to local recurrence of tumor and distant lung metastasis 2 months after the surgery. In case with rapid growth of a lesion or unusual severe pain, one must have a high index of suspicion with regard to dedifferentiation.

• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.507-512
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• 2001

Feature-based similarity has become an important research issue in multimedia database systems. The features of multimedia data are useful for discriminating between multimedia objects. the performance of conventional multidimensional data structures tends to deteriorate as the number of dimensions of feature vectors increase. The $R^{*}-Tree$ is the most successful variant of the R-Tree. In this paper, we propose a SOM-based $R^{*}-Tree$ as a new indexing method for high-dimensional feature vectors. The SOM-based $R^{*}-Tree$ combines SOM and $R^{*}-Tree$ to achieve search performance more scalable to high-dimensionalties. Self-Organizingf Maps (SOMs) provide mapping from high-dimensional feature vectors onto a two-dimensional space. The map is called a topological feature map, and preserves the mutual relationships (similarity) in the feature spaces of input data, clustering mutually similar feature vectors in neighboring nodes. Each node of the topological feature map holds a codebook vector. We experimentally compare the retrieval time cost of a SOM-based $R^{*}-Tree$ with of an SOM and $R^{*}-Tree$ using color feature vectors extracted from 40,000 images. The results show that the SOM-based $R^{*}-Tree$ outperform both the SOM and $R^{*}-Tree$ due to reduction of the number of nodes to build $R^{*}-Tree$ and retrieval time cost.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7C
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• pp.675-686
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• 2005

In this paper, we propose an efficient face region detection technique for the content-based video summarization. To segment video, shot changes are detected from a video sequence and key frames are selected from the shots. We select one frame that has the least difference between neighboring frames in each shot. The proposed face detection algorithm detects face region from selected key frames. And then, we provide user with summarized frames included face region that has an important meaning in dramas or movies. Using Bayes classification rule and statistical characteristic of the skin pixels, face regions are detected in the frames. After skin detection, we adopt the projection method to segment an image(frame) into face region and non-face region. The segmented regions are candidates of the face object and they include many false detected regions. So, we design a classifier to minimize false lesion using CART. From SGLD matrices, we extract the textual feature values such as Inertial, Inverse Difference, and Correlation. As a result of our experiment, proposed face detection algorithm shows a good performance for the key frames with a complex and variant background. And our system provides key frames included the face region for user as video summarized information.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.4
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• pp.419-429
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• 2003

A three-dimensional (3-D) method of analysis is presented for determining the free vibration frequencies of thick, hyperboloidal shells of revolution. Unlike conventional shell theories, which are mathematically two-dimensional (2-D), the present method is based upon the 3-D dynamic equations of elasticity. Displacement components u/sub r/, u/sub θ/, u/sub z/ in the radial, circumferential, and axial directions, respectively, we taken to be sinusoidal in time, periodic in θ, and algebraic polynomials in the r and z directions. Potential(strain) and kinetic energies of the hyperboloidal shells are formulated, and the Ritz method is used to solve the eigenvalue problem, thus yielding upper bound values of the frequencies by minimizing the frequencies. As the degree of the polynomials is increased, frequencies converge to the exact values. Convergence to four digit exactitude is demonstrated for the first five frequencies of the hyperboloidal shells of revolution. Numerical results are tabulated for eighteen configurations of completely free hyperboloidal shells of revolution having two different shell thickness ratios, three variant axis ratios, and three types of shell height ratios. Poisson's ratio (ν) is fixed at 0.3. Comparisons we made among the frequencies for these hyperboloidal shells and ones which ate cylindrical or nearly cylindrical( small meridional curvature. ) The method is applicable to thin hyperboloidal shells, as well as thick and very thick ones.

• Food Science and Preservation
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• v.13 no.5
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• pp.538-542
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• 2006

Physicochemical properties and positional distribution of Hallabong Tangor (Citrus Kiyomi ${\times}$ ponkan) cultivated in heated greenhouse were investigated. About 90% of Hallabong produce fruit within the range of $250{\sim}400g$ fruit weight on a tree, larger fruits were mainly consisted of $400{\sim}450g$ in M16A, a variant species of Hallabong, due to younger tree and fruit thinning. Nevertheless fruit sizes of M16A were larger than Hallabong, and peel thickness of M16A (3.29 mm) was thinner than that of Hallabong (3.51 mm). Hardness of m6h was 994.69g-force, compared to 832.8 g-force of Hallabong on the average. Soluble solids and acid content of Hallabong were $12.20{\sim}12.98^{\circ}Brix$ and $1.08{\sim}1.14%$, while those of M16A were $1.48{\sim}12.63^{\circ}Brix$ and $0.92{\sim}1.00%$, respectively. Vitamin C content of Hallabong was $71.30{\sim}78.77 mg/100 g$, compared to $64.40{\sim}68.01mg/100g$ in M16A. Soluble solid in the part of stem was lower than that of end part among the same segment. Fruit size in the upper part of the tree was larger, the peel was thicket and flesh ratio was lower than the middle or lower part. However, soluble solids and acid content were high, due to cumulative sunshine during cultivation.

• Food Science and Preservation
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• v.13 no.5
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• pp.611-615
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• 2006

Physicochemical properties of Hallabong Tangor(Citrus Kiyomi ${\times}$ ponkan) cultivated in Heated greenhouse were investigated. Moisture contents of Hallabong and M16A (a variant species of Hallabong) were 87.42% and 88.12% total sugar were 8.01% and 7.81% and acid content were 1.09% and 0.99% respectively. Vitamin C content of Hallabong was 72.01 mg/100 g that was higher than Citrus unshiu. Potassium content of M16A was 938.33 mg/kg, while Hallabong was 1369.33 mg/kg. The contents of inorganic element in a decreasing order were K > Ca > P > Mg > Na in Hallabong, and K > P > Ca > Mg > Na in Ml6A. Sucrose in Hallabong and M16A were 3.60% and 4.36%, respectively, which is half of total free sugars. Fructose and glucose Hallabong and M16A were 2.22% and 1.90%, 1.94% and 1.65% respectively. Citric acid in Hallabong and M16A was 82.32% and 69.88%, respectively among total organic acids. The content of malic acid was higher in M16A, compared to Citrus unshiu. Hesperidin and narirutin were identified main flavonoids.

• Food Science and Preservation
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• v.14 no.6
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• pp.565-570
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• 2007

Changes in the quality of Hallabong tangor during growth stage and with temperature pre-treatment after harvest were investigated. Soluble solids of Hallabong increased continuously until early December. The acid content of M16A, a variant species of Hallabong, decreased by 1% after October and continued to decrease until the middle of January. After ripening, treatment to reduce the acid content was required. Fruit firmness decreased gradually until November and was maintained at 1000 g-force after this time. Soluble solids and acid content were $13.3{\pm}0.83^{\circ}Brix$ and $1.07{\pm}0.52%$. Soluble solids increased in temperature-treated Hallabong with prolonged storage, but acid content did not decrease. Fruit firmness also decreased with storage period, regardless of temperature pre-treatment. Therefore, water management during cultivation, temperature treatment above $35^{\circ}C$ after harvest, and checking of the acid content and soluble solids with prolonged storage are recommended in achieving high quality Hallabong.

• The korean journal of orthodontics
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• v.35 no.2 s.109
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• pp.116-126
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• 2005

The object of this study was to evaluate how friction that occurs during the sliding movement of an orthodontic archwire through orthodontic brackets is differently affected by variant designs and ingredients of brackets and archwires and bracket-archwire angles. In order to simulate the situations which could occur during orthodontic treatment with fixed appliances, 4 types of brackets (Gemini, a stainless steel twin bracket, Mini Uni-Twiu. a stainless steel bracket with a single bracket design and narrow mesio-distal width; Clarity, a metal-reinforced ceramic bracket; Transcend, a ceramic bracket) and 3 types of orthodontic archwires $(0.016',\; 0.016{\times}0.022'\;stainless\;steel,\;0.016'\;Nitinol)$ were used and the bracket-archwire angles were controlled as $0^{\circ},\;3^{\circ}\;6^{\circ},\;and\;9^{\circ}$ Gemini significantly show and the lowest static and kinetic frictions (P<0.001) Clarity showed the highest static and kinetic frictions with a bracket-archwire angle of $0^{\circ}$. and Transcend at $6^{\circ}\;and\;9^{\circ}$ (P<0.001). An $0.016{\times}0.022'$ stainless steel rectangular archwire significantly showed the highest static and kinetic frictions (P<0.01). The lowest static and kinetic frictions were observed when the bracket-archwire angles were $0^{\circ}\;and\;3^{\circ}$ with 0.010' stainless steel round archwires (P<0.01), and $6^{\circ}\;and\;9^{\circ}$ with 0.016 Nitinol (P<0.001). The static and kinetic frictions were increased as the bracket-archwire angles were increased (P<0.001)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.5
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• pp.535-542
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• 2007

Ameloblastoma, a benign tumor of odontogenic type, represents 10% of all tumors of the jaw. It is localized in the mandible(80%) and in the maxilla(20%). In every case, the selection of the surgical treatment must consider some fundamental elements, including the age and general state of health the clinicopathological variant, and the localization and extent of the tumor. This study was invested the clinicopathological findings of 23 patients with ameloblastoma which had been diagnosed by biopsy during the period of 1987 to 2005 at Chonnam National University Hospital. And it contained the statistical analysis according to the treatment methods and the clinicopathological findings such as sex, age, location, chief complaints, duration, radiographic findings, histologic findings, treatment methods. The results obtained are were follows. The age of patient ranged from 10 to 91 years(means, 35.9 years) at biopsy. Thirteen(57%) of the 23 subjects were males, and 10(43%) were females. Twenty(87%) of the 23 ameloblastomas were located in the mandible. Swelling was the most common symptom and was experienced by 20(87%) patients. Radiographically, 11(48%) of the 23 tumors were unilocular with a well-demarcated border and 12(52%) were multilocular. The most common histologic pattern was plexiform and acanthomatous rather then follicular. Conservative treatment was performed 7 cases(30%), radical treatment 11 cases(48%), and combined treatment 5 cases(22%). Follow-up period ranged from 2.1 years to 22 years(mean 5.1 years). Based on the above results, surgical excision after marsupialization was found to be useful as a preliminary treatment of the large cystic ameloblastoma in children and adolescents. On the contrary, the lesion with a soap bubble appearance, the one with ineffective marsupialization was subjected to extensive excision of the tumor with a wide margin of normal bone.

• Journal of dental hygiene science
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• v.16 no.1
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• pp.18-25
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• 2016

The purpose of this study was to investigate a reliability and validity of the Korean version for measuring tool the job embeddedness of dental hygienists. The survey was modified and revised to fit into Korean culture. A survey was conducted with 274 dental hygienists in dental clinics. The data was used for the analysis of the study, using PASW Statistics 18.0 and IBM SPSS AMOS 7.0. The factor analysis showed that the job embeddedness of the dental hygienists was composed of three elements, namely 'organization fit', 'job connectivity', and 'personnel relationships'. The validity of the model examined by a confirmatory factor analysis satisfied most of the relevant requirements. All of the factors had the conceptual reliability and variant extracted index above the minimum requirements, ensuring reliability and concentrated validity. The Cronbach's alpha shows a good reliability. In conclusion, it was proven that dental hygienist's job embeddedness measurement tool has high validity and reliability. Further, this study could be used to improve dental hygienist's long term working, and the growth stage of dental clinic.