A General Procedure for Estimating the General Parameter Using Auxiliary Information in Presence of Measurement Errors

Singh, Housila P.,Karpe, Namrata The Korean Statistical Society 2009 Communications for statistical applications and me Vol.16 No.5

This article addresses the problem of estimating a family of general population parameter ${\theta}_{({\alpha},{\beta})}$ using auxiliary information in the presence of measurement errors. The general results are then applied to estimate the coefficient of variation $C_Y$ of the study variable Y using the knowledge of the error variance ${\sigma}^2{_U}$ associated with the study variable Y, Based on large sample approximation, the optimal conditions are obtained and the situations are identified under which the proposed class of estimators would be better than conventional estimator. Application of the main result to bivariate normal population is illustrated.

방사선조사가 악하선 미세혈관과 내피세포에 미치는 영향에 관한 실험적 연구

최갑식,최미,손정익,유영아,배용철 大韓口腔顎顔面 放射線學會 1994 Imaging Science in Dentistry Vol.24 No.1

The purpose of this study was to investigate the irradiation effects on the capillary and endothelial cell in the submandibular gland. Sprague-Dawley strain male rats were singly irradiated to their neck region with the dose of 5Gy and 10Gy by 6MV X-irradiation and sacrificed on the 6 hours, 12 hours, 1,3,7, and 14 days after irradiation. The authors observed the histological changes of the capillary at H & E and PAS staining under a light microscope, and also observed the ultrastructural changes of the endothelial cell using a transmission electron microscope. The obtaining results were as follows: 1. In the light microscopic examination, the capillary density was slightly increased on the 1 day after irradiation, and increased until the 7 days after irradiation. After then, capillary density was apparently decreased. 2. The reaction to PAS staining at acinar cells was decreased on the 6 hours after irradiation, and recovered on the 7 days after irradiation. But reaction was decreased on the 14 days after irradiation again, after then, gradually recovered with days. 3. In the transmission electron microscopic examination, mild proliferation of cytoplasmic process of the endothelial cell and reduction in luminal size were observed just after irradiation. After then, nuclear degeneration, marked proliferation of cytoplasmic process, thickened basal lamina, and numerous cytoplasmic vesicles were observed on the 1 day after irradiation. These changes were recovered to normal on the 14 days after 5GY group, but not with 10GY irradiation group. And destruction of endothelial cell and loss of basal lamina were not observed in both groups. 4. From the above results, reduction in luminal size, proliferation of cytoplasmic process and thickening of basal lamina were observed as the irradiation effects on the capillary and endothelial cell of the submandibular gland. And also, these changes may induce increase in capillary number and endothelial permeability by means of increase of cytoplasmic vesicle formation. The changes appeared earlier and more prominent in 10Gy irradiated group than in 5Gy irradiated group.

하악에 발생된 법랑모 섬유육종

최갑식,이은숙,박태원,최미 大韓口腔顎顔面 放射線學會 1993 Imaging Science in Dentistry Vol.23 No.2

The ameloblastic fibrosarcoma is the malignant counterpart of the ameloblastic fibrosarcoma in which the mesenchymal element has become malignant. Clinically it frequently occurs in the 3rd and 4th decades, and more frequent in the mandible than in the maxilla. Radiographic features are apparent multiocular radiolucency with ill-defined border. The authors experienced two cases of ameloblastic fibrosarcoma of the mandible in a 26-year-old male and a 48-year-old female patients who suffered from pain and swelling on the affected area. And we discussed the clinical, radiological and histopathological features of this disease with a brief review of the literatures.

치성각화낭과 단방성 법랑모세포종의 감별에 관한 방사선학적 연구

최갑식 大韓口腔顎顔面 放射線學會 1995 Imaging Science in Dentistry Vol.25 No.1

The purpose of this study was to obtain some informations for the radiographic differential diagnosis between odontogenic keratocyst and unicystic ameloblastoma in the mandible. The author compared and analysed the clinico-radiographic features of 48 cases of odontogenic keratocyst and 32 cases of unicystic ameloblastoma. The obtained results were as follows: 1. Odontogenic keratocyst and unicystic ameloblastoma occurred the most frequently in the 2nd and 3rd decades, and both lesions occurred with slight predilection in males. The most frequent lesional site was molar area in odontogenic keratocyst(50.0%) and mandibular angle and ramus area in unicystic ameloblastoma(71.9%). 2. Cortical thinning and expansion were observed with simliar occurrences in odontogenic keratocyst(77.1%) and in unicystic ameloblastoma(72.9%). 3. Typical undulating lesional border was observed more frequently in odontogenic keratocyst(79.2%) than in unicystic ameloblastoma(46.9%). 4. Well-defined lesional outline occurred more frequently in odontogenic keratocyst(97.9%) than in unicystic ameloblastoma(53.1%). 5. Root resorption of adjacent teeth occurred more frequently in unicystic ameloblastoma(65.2%) than in odontogenic keratocyst(18.8%) respectively, but loss of lamina dura was frequently observed in odontogenic keratocyst(79.2%). And tooth displacement occurred more frequently in odontogenic keratocyst(50.0%) than in unicystic ameloblastoma(17.4%). 6. Displacement of mandibular canal occurred more frequently in odontogenic keratocyst(75.0%) than in unicystic ameloblastoma(61.5%). 7. Inhomogeneous lesional radiolucency occurred more frequently in unicystic ameloblastoma(53.1%) than in odontogenic keratocyst(39.6%).

口內全顎標準放射線寫眞 撮影時 撮影法과 필름維持法에 따른 撮影上의 失策

崔甲植,卞鍾秀,崔珣哲 大韓口腔顎顔面 放射線學會 1986 Imaging Science in Dentistry Vol.16 No.1

75명의 치과대학 4학년생들이 촬영한 300예의 구내전악표준방사선사진들을 촬영법과 필름의 유지법에 따라 필름들을 피촬영자의 엄지나 검지로 유지하고 등각법으로 촬영한 경우(Ⅰ군), 필름을 Rinn Snap-A-Ray기구로 유지하고 등각법으로 촬영한 (Ⅱ군), 필름을 Rinn XCP 기구로 유지하고 Short cone에서 평행법으로 촬영한 경우(Ⅲ군), 필름을 Rinn XCP기구로 유지하고 Long cone에서 평행법으로 촬영한 경우 (Ⅳ군)으로 분류하여 75예의 구내전악표준방사선사진으로 구성된 각 군의 재촬영의 조사하여 각 군에서 가장 많이 나타난 실책의 종류와 부위, 그리고 구내전악표준방사선사진 1회당 평균재촬영매수에 대해 아래의 결과를 얻었다. Ⅰ군 : Incorrect film placement(47.8%)와 상악 견치부(26.9%)였으며 0.89매였다. Ⅱ군 : Incorrect film placement(44.0%)와 상악대구치부(28.6%)였으며 1.12매였다. Ⅲ군 : Incorrect film placement(79.1%)와 상악대구치부(32.0%)였으며 2.05매였다. Ⅳ군 : Incorrect film placement(67.7%)와 상악대구치부(30.7%)였으며 1.69매였다. 평균재촬영매수에서는 같은 촬영법인 Ⅰ군과 Ⅱ군간에서와 Ⅲ군와 Ⅳ군간에서는 유의한 차가 나타나지 않았으나(P>0.05),등각촬영법의 군(Ⅰ+Ⅱ)보다 평행촬영법의 군(Ⅲ+Ⅳ)에서 0.86매 많았다(P<0.01). The purpose of this study was to investigate the numbers and causes of retakes in 300 complete mouth radiographic surveys made by 75 senior dental students. According to radiographic techniques and film holding methods, they were divided into 4 groups: GroupⅠ: Bisecting-angle technique with patient's fingers. GroupⅡ: Bisecting-angle technique with Rinn Snap-A-Ray device. GroupⅢ: Paralleling technique with Rinn XCP instrument(short cone) GroupⅣ: Paralleling technique with Rinn XCP instrument(long cone) The most frequent cause of retakes, the most frequent tooth area examined, of retakes and average number of retakes per complete mouth survey were evaluated. The obtained results were as follows: GroupⅠ: Incorrect film placement (47.8%), upper canine region, and 0.89. GroupⅡ: Incorrect film placement (44.0%), upper molar region, and 1.12. GroupⅢ: Incorrect film placement (79.2%), upper molar region, and 2.05. GroupⅣ: Incorrect film placement (67.7%), upper molar region, and 1.69. The average number of retakes per complete mouth survey of paralleling technique (GroupIII+IV) was higher than that of bisecting-angle technique (GroupI+II)(p<0.01). There was no differnce between GroupⅠand Group Ⅱ, and between Group Ⅲ and Group Ⅳ in the average number of reatkes per complete mouth survey(p>0.05).

섬유성이형성증과 골화섬유종의 방사선학적 감별진단

최갑식 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.1

The author observed and compared the radiographic features of 49 cases of the fibrous dysplasia and 14 cases of the ossifying fibroma in the osteoblastic or mature stage radiologically and histopathologically. The obtained results were as follows: 1. Fibrous dysplasia occurred most frequently in the 2nd decade, but ossifying fibroma in the 3rd and 4th decades, and both lesions occurred with slight predilection in females. 2. In most cases, chief complaints were painless facial swelling. And 61.1% of fibrous dysplasia occurred in the maxilla, 92.9% of ossifying fibroma in the mandible, and most of these lesions occurred in the premolar-molar region. 3. In the mandibular lesions, ossifying fibroma was shown more oval and round shape, but fibrous dysplasia was shown fusiform shape. 4. Fibrous dysplasia was shown homogeneously distributed, complete radiopaque shadow at 63%, and ossifying fibroma was shown concentric, mixed appearance of radiolucent and radiopaque shadow at 92.9%. 5. Fibrous dysplasia was entirely shown poorly outlined and blended to normal surrounding bone, but ossifying fibroma was shown well-defined border. 6. Cortical thinning and expansion were observed in these lesions, but degree of cortical expansion was more severe in ossifying fibroma than fibrous dysplasia. 7. Loss of lamina dura, tooth displacement, and displacement of mandibular canal were observed in both lesions, but root resorption was observed in ossifying fibroma only.(J Korean Oral Maxillofac Radiol 1999:29:55-63)

다골성 섬유성 이형성증

최갑식,박상억,이강숙 大韓口腔顎顔面 放射線學會 1994 Imaging Science in Dentistry Vol.24 No.1

Fibrous dysplasia is a benign fibro-osseous condition that is replacement of normal bone and marrow tissues by cellular fibrous tissue and immature bone, and it is divided into monostotic type and polyostotic type. Polyostotic fibrous dysplasia involves multiple bones, such as skull, jaw bones, femur and tobia. And it is also divided into two forms: the less severe Jaffe's type and the more severe Albright's syndrome. Clinically, it frequently occurs in the 2nd decade, and occurs more frequently in maxilla than in mandible. And the lesions of fibrous dysplasia tend to become static as skeletal maturity is reached. The authors experienced three cases of polyostosic fibrous dysplasia in the craniofacial area with the complaints of facial asymmetry due to painless swelling. And we discussed the clinical, radiological, and histopathological features of these cases with a brief review of the literatures.

악골에 발생된 특발성 골경화증에 관한 방사선학적 연구

최갑식,최미,안상희 大韓口腔顎顔面 放射線學會 1994 Imaging Science in Dentistry Vol.24 No.1

The purpose of this study was to evaluate the prevalence, distribution, and its relation with adjacent roots of idiopathic osteosclerosis in the jaws by means of the analysis of the 6,220 persons' full mouth periapical radiographs. And the following results were obtained; 1. The prevalence of idiopathic osteosclerosis in the jaws was revealed to be 2.43% in total examined persons, and there was a higher prevalence in females(3.12%) than in males(1.68%) 2. There was a higher prevalence in the mandible(94.3%) than in the maxilla(5.7%), and the most frequently involved area was the mandibular premolar area(51.9%), followed by mandibular molar area(21.52%). 3. According to the types of relation with adjacent roots, separated type(53.8%) in idiopathic osteosclerosis was the most frequent, followed by apical type(40.51%), interradicular type(e.18%), apical and interradicular type(2.51%) in descending order of frequency.

관전압 변화에 따른 방사선사진의 흑화도와 대조도

최갑식 慶北大學校 齒科大學 1990 慶北齒大論文集 Vol.7 No.2

The purpose of this study to evaluate the influence on radiographic density and contrast of 7-steps aluminum stepwedge according to kilovoltage changes(65-85 kVp range). And the influence on radiographic interpretation of experimentally produced bony lesions under kVp related radiographic densities is also examined. The following results were obtained. 1. The radiographic density of the aluminum stepwedge is increased with the increase of kVp, and increasing tendency of radiographic density is decreased with the increase of aluminum steps. 2. The range of radiographic contrast reveals 0.09-0.32 at 65-85 kVp range, and difference of radiographic contrast score is decreased with the increase of aluminum steps. 3. There is no influence on radiographic interpretation of experimentally produced bony lesions under the radiographic density range of 0.75-1.49.

파노라마방사선사진상의 이공에 관한 연구

최갑식,배용철,김동윤,손정익 경북대학교 의학연구소 1999 경북대학교병원의학연구소논문집 Vol.3 No.1

The purpose of this study was to evaluate the position and shape of mental foramen in panoramic radiographs. For this study, panoramic radiographs were obtained from the 200 adults and evaluated the position and shape of mental foramen. According to various positional changes in panoramic radiographs of the patients, the author also obtained panoramic radiographs from the 100 adults and then evaluated the positional and shape changes of mental foramen. The following results were obtained: 1. Shapes of metal foramen were observed elliptical(43.3%), round or oval(42.5%), unidentified(7.5%) and diffuse (6.7%) type in descending order of frequency. 2. Horizontal position of mental foramen were most frequently observed at the 2nd premolar area(54.2%), and area between the 1st premolar and 2nd primolar(43.1%), area between the 2nd premolar and 1st molar(2.7%) in descending order of frequency. 3. Vertical position of mental foramen were most frequently observed at the inferior of apex(88.2%), and at apex (9.7%), overlap with apex(1.9%), superior of apex(0.2%) in descending order of frequency. 4. According to various positional changes in panoramic radiographs of the patients, shape changes of mental foramen were more obviously observed at the forward 10mm and chin down 10。 positioned panoramic radiographs. And changes of horizontal and vertical position were observed in similar to compared with normal positioned panoramic radiographs.