안면비대칭 정도에 따른 정모 두부방사선사진관 3차원영상의 비교 연구

조홍규,김경근,황현식 전남대학교 치과대학 2001 구강과학 Vol.13 No.2

The purpose of this study was to find out the problems of P ­ A cephalometric measurements used in the facial asymmetry analysis and to show the necessity of using three ­ dimensional morphometry. Steel ball (1.2㎜ in diameter) were attached in twenty seven landmarks of symmetrical artificial human skull, and eighty seven different asymmetrical artificial human skulls were formed by enlarging gradually remus height, mandibular body length, and gonial angle of the hemiface. From the P ­ A cephalometry and three ­ dimensional morphometry of each skull types, three linear measurements (representing ramus height, mandibular body length, mandibular length) and two angle measurements (representing gonial angle, menton deviation) and two area measurements (representing mandibular area, lower facial area) were acquired and made into asymmetry index. Menton deviation itself was used as asymmetry index while left ­ right differences were used in the other measurements. These asymmetry index were compared with each other to show the different aspect of the seven asymmetry index according to the degree of actual facial asymmetry. Through the statistical analysis, following results were obtained. 1. When actual ramus height difference becomes large, menton deviation and lower facial area asymmetry index of P ­ A cephalometry were reduced significantly more than those of three ­ dimensional morphometry (p<0.001). 2. When actual mandibular body length difference becomes large, ramus height, lower facial area asymmetry index of P ­ A cephalometry were reduced significantly (p<0.001) while mandibular body length, mandibular length, gonial angle, and mandibular area asymmetry index of P ­ A cephalomentry were magnified significantly more than those of three ­ dimensional morphometry (p<0.01). 3. When actual gonial angle difference becomes large, gonial angle asymmetry index of P ­ A cephalometry was reduced significantly (p<0.001) while lower facial area, mandibular body length, and mandibular area asymmetry index were magnified significantly more than those of three ­ dimensional morphometry (p<0.01). 4. When the correlation between actual ramus height difference and seven asymmetry index of P ­ A cephalometry and three ­ dimensional morphometry was analysed, no difference between P ­ A cephalometry and three ­ dimensional morphometry was found (p<0.01). 5. When the correlation between actual mandibular body length difference and seven asymmetry index of P ­ A cephalometry and three ­ dimensional morphometry was analysed, significance was found in mandibular body length, mandibular length, menton deviation, mandibular area, and lower facial area (p<0.001) while significance was found only in gonial angle of three ­ dimensional morphometry (p<0.01). 6. When the correlation between actual gonial angle difference and seven asymmetry index of P ­ A cephalometry and three ­ dimensional morphometry was analysed, significance was found in gonial angle (p<0.001) while significance was found only in lower facial area of three ­ dimensional morphometry (p<0.01). The above results suggest that three ­ dimensional morphometry show to be necessary for the accurate facial asymmetry analysis.

전기도금을 이용한 교정용 선재의 직경 증가에 관한 실험적 연구

조진형,김경근,황현식 전남대학교 치과대학 2001 구강과학 Vol.13 No.2

The purpose of this study was to evaluate the possibile clinical application of electroplating to increase diameter of an orthodontic wire, through examining the change of physical properties. The diameter of stainless steel orthodontic wire was increased from 0.016 inch to 0.018 inch by electroplating in a bath of nickel sulfate 100g/L, nickel chloride 60g/L, boric acid 30g/L, and sodium chloride 50g/L, under the conditions of 1.7V, 25∼29℃, and 3.1∼3.3pH. During the electroplating, the rate of diameter increase was measured every minute. To investigate uniformity, the diameter was measured at three different locations of each wire specimen after electroplating. An X-ray diffraction test was performed to analyze the nature of the electroplated metal. Following heat treatment to improve adhesion between the wire and electroplated metal, a three­point bending test was conducted to compare stiffness, yield strength, and ultimate strength among four wire groups; 0.016 inch, electroplated 016, electroplated and heat ­ treated 016, and 0.018 inch wires. Through the comparison of each wire group, following results were obtained. 1. In the lad ­ deflection graph, the curve of the eletoplated group was placed between that of the 0.016 inch group and the 0.018 inch group, and the curve closer to the 0.018 inch group by heat treatment. 2. In the electroplated and heat ­ treated 016 wire group, the values of stiffness, yield strength and ultimate strength showed higher tendency than in the original 0.016 inch group. Stiffness and ultimate strength showed statistically significant differences between two groups. 3. Stiffness, yield strength, and ultimate strength of electroplated wire presented lower values than those of 0.018 inch wire group. 4. stiffness, yield strength, and ultimate strength of electroplated and heat ­ treated wire showed higher tendency than those of electroplated wire group, and ultimate strength showed statistically significant difference between two groups. 5. After electroplating, the difference in diameter between the three locations was withing 0.1´0.3% variation, and showed no statistical significance.

DS-CDMA의 수용 능력에 관한 연구

조경구,나현식 湖南大學校 情報通信硏究所 1999 정보통신연구 Vol.9 No.-

본 연구에서는 전력제어가 정확하며 해당 셀에서 가입자 수가 균일하다는 가정하에 단일셀에서 CDMA와 FDMA, TDMA 간의 가입자 수를 비교하였다. 다른 기술들이 결합되지 않은 순수한 CDMA의 가입자 수용능력은 단일 셀이 다중 셀에서 FDMA, TDMA와 큰 차이가 없으나, 음성활성화계수(VAC)와 섹터화 안테나 등 간섭 신호를 감소시키는 기술이 결합된 경우는 상대적으로 많은 이득이 있는 것으로 나타났다. In this paper, radio capacity between CDMA and FDMA, TDMA in a single cell under an accurate power control was compared. The pure CDMA has no significant capacity difference over FDMA, TDMA. However, with interference reduction techniques, sectored antenna and voice activity factor combined CDMA shows the greater performance on capacity than FDMA, TDMA regardless data rates.

발포 유기질 단열재의 경시특성에 관한 연구

조항선,김우식,염경호,남궁식 연세대학교 산업기술연구소 1984 논문집 Vol.16 No.1

The aging properties of cellular plastic insulations(EPS,PUF and UFF) were investigated by varying temperature, relative humidity and time. The time aging properties were changed with in 10 - 12% of initial properties at high temperature(above 318K) and relative humidity (above 90%). The amount of HCHO gas release from UFF was increased as temperature and relative humidity increased, and HCHO release rate was decreased exponentially with time.

구개골내 정중치에서 발생한 함치성낭종 1례

조원표,김재영,서경식 건국대학교 의과학연구소 1995 건국의과학학술지 Vol.5 No.-

Dentigerous cyst may occur any place around jaw. Dentigerous cyst can develop from unerupted tooth, and cyst from supernumerary tooth is rare. Among dentigerous cyets, palatal dentigrous cyst from a mesiodens is a very rare case. So we report a large(2.5×2.5㎝) dentigerous cyst arising from a mesiodens which was found at left premaxillary area eroding palate, premaxilla, nasal floor and roots of left upper central and lateral incisors. En bloc enucleation of the cyst was performed and the large bony defect was filled with antibiotic and thrombin-impregnated Gelfoam. The incision site was closed with meticulous water-tight interrupted 5-0 nylon sutures. We report with follow up CT scans after 4 months. So far as we have followed up the patient, filling the bony defect with thrombin and ??, a absorbable gelatin sponge revealed a good tissue replacement material.

비내시경 수술로 치험한 급성 사골동염에 의한 안와봉와직염 1례

서경식,허창호,조병주 건국대학교 의과학연구소 1996 건국의과학학술지 Vol.5 No.-

Inflammation involving the orbit is an omnious physical sign representing a threat to vision and life. Seventy-five percent of bacterial infections in the orbit are caused by paranasal sinusitis, usually ethmoiditis medially, less commonly from the frontal sinusitis above or maxillary sinusitis below. Orbital complication induced by acute sinusitis is a rare condition in nowadays since the advent of antibiotics. We report a case of treatment for periorbital cellulitis induced by acute ethmoiditis. A 37-year-old male patient visited the otolaryngologic out patient clinic with symptom of severe headache around left orbital area for 2 days. The physical examination revealed no gross abnormality on the face except mucopurulent discharges from the left middle meatus. A plain paranasal sinus films showed partial haziness in the left ethmoid sinus and frontal sinus. The patient was admitted due to a severe headache. On the evening of admission day the patient's left eyeball was protruded and periorbital edema occured. Although the administration of maximal doses of parenteral antibiotics, the edema and protrusion of left eyeball became worse. The orbital sonogram showed cellulitis in the left orbital area and the PNS CT scans showed left ethmoiditis and frontal sinusitis. An emergency intranasal ethmoidectomy under the endoscopic control was performed on the third admission day. On the second post-operative day the patient's eyelid swelling decreased. On the sixth post-operative day the patient was discharged without any orbital sequela. We report this case with review of the literature.

누설자속법을 이용한 저장탱크 바닥판재의 부식평가

원순호,조경식 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.1

본 연구에서는 누설자속법을 적용한 저장용 탱크 바닥판재의 부식측정 기술에 관한 연구를 수행하였다. 시험편은 두께 6mm 및 10mm 강판에 20%, 40%, 60%, 80%의 깊이를 갖는 홈을 가공한 대비시험편을 사용하였다. 영구자석을 이용하여 요크를 제작하고 홀센서를 이용하여 시험편에서 누설자속을 측정하였다. 실험결과는 인공홈에서 발생된 누설자속을 효과적으로 검출할 수 있다는 것을 보여주었다. 또한 transverse형 홀센서를 이용하여 시험편에 가공한 홈의 크기를 근사적으로 측정할 수 있다는 결과를 제시하였다. 홈의 위치에 따른 누설자속 진폭을 측정한 결과, 누설자속법으로는 판재 상, 하부의 홈 위치를 구별할 수 없다는 것이 밝혀졌고, lift-off 거리에 따라서 진폭이 현저하게 변하기 때문에 고정된 lift-off 거리를 유지하는 것이 중요하다는 사실을 보여주었다. In this research, MFL technique has been studied for the inspection of storage tank floor. The reference specimens having 20%, 40%, 60% and 80% slot's are fabricated using the carbon steel plates of a 6mm and 10mm thick. Powerful permanent magnets and Hall effect sensors are used to this application. It is shown that our system is able to detect metal loss like a slot. Also, it is possible that slot diameter is measured using transverse type of Hall generator. It is demonstrated that MFL can not differentiate between the response from top side and bottom side slot. Flux leakage response from a bottom side indication is significantly lower in amplitude than that from an equivalent top side slot. It is essential to know this sensor lift-off distance because the MFL signal also changes considerably with the sensor lift-off distance.

企業引受와 長期經營成果와의 關係 : 거평그룹을 中心으로 Focused on Keopyung Group

金熙錫,曺敬植 大邱大學校 社會科學硏究所 1999 社會科學硏究 Vol.6 No.2

본 연구에서는 거평그룹의 타기업 인수가 장기적인 관점에서 그 기업의 경영성과에 어떠한 영향을 미치고 있는가를 분석하기 위하여 기업의 경영성과를 측정하는 가장 대표적인 지표로 인정받고 있는 총자본순이익률(ROA), 자기자본순이익률(ROE), 매출액순이익률(ROS)을 기준으로 인수전·후의 기업경영성과를 t-검정을 통하여 측정하였다. 분석결과 거평인수기업의 ROA, ROE, ROS와 산업평균지표간에는 유의적인 차이가 없는 것으로 밝혀졌는데, 이것은 거평그룹의 인수기업 경영성과가 인수로 인해 산업평균에 비해서 더 나아지지는 않았음을 나타낸다. 반면에 기업의 위험은 인수이전에 비해 더욱 증가하였는데, 이러한 현상은 거평그룹의 기업인수 역시 과거 대다수 우리나라 기업의 M&A에서와 같이 기업경영성과의 향상 또는 株主富의 극대화보다는 量的 外形불리기에 급급하였음을 보여 주는 것이라 할 수 있다.

수소손상 검출과 평가기술

원순호,현양기,이종오,조경식,이재도 한국비파괴검사학회 2002 한국비파괴검사학회지 Vol.22 No.1

산업현장에서 수소는 설비를 손상시킬 수 있는 주원인 중의 하나이며, 종종 설비를 파괴시키는 사고를 발생시킨다. 수소손상에 의한 결정립계의 공동 또는 미세균열은 강재의 파괴인성과 강도를 떨어뜨리는 원인이 되고, 따라서 과거 제한적인 방법으로 수소손상을 평가하기 위한 시도가 수행되었다. 본 연구에서는 초음파를 적용하여 수소손상을 검출하고 평가하기 위한 연구를 수행하였다. 미세조직시험에 의해 확인된 시험편을 이용하여 초음파의 속도와 감쇠계수를 구한 결과, 수소손상에 의해서 초음파 속도는 감소하고 감쇠는 현저하게 증가하는 것으로 나타났다. 이러한 결과를 바탕으로 수소손상을 검출하기 위한 신뢰성 있는 평가법을 제시하였다. The presence of hydrogen in industrial plants is a source of damage. Hydrogen attack is one such form of degradation and often causing large tube ruptures that necessitate an immediate shutdown. Hydrogen attack may reduce the fracture toughness as well as the strength of steels. This reduction is caused partially by the presence of cavities and microcracks at the grain boundaries. In the past several techniques have been used with limited results. This paper describes the application of an ultrasonic velocity and attenuation in hydrogen damage. Ultrasonic tests showed a decrease in wave velocity and an increase in attenuation. Such results demonstrate the potential for ultrasonic nondestructive testing to quantify damage. Based on this study, reliable recommendation is suggested to detect hydrogen attack.

한국의 시대별 자활복지행정에 관한 연구: 자활사업 제도화 이전을 중심으로

조경식 ( Kyung Shik Cho ) 한국행정사학회 2011 韓國行政史學誌 Vol.28 No.-

본 연구는 1961년 생활보호법의 제정의 시기부터 자활사업의 제도화 이전인 제6공화국시대까지의 자활복지행정의 역사를 고찰하여 오늘날의 자활복지정책에 합의를 도출하고자 한 것이다. 외원에 의한 구호정책으로 시작된 우리나라 초기의 구호정책은 제3공화국에 접어들어 법적제도가 마련되었고, 새마을 운동으로 촉발된 자조·자립의 정신은 1980년대의 민간자활운동으로 이어져 1996년 이후 제도화의 촉발요인으로 작용하게 된다. 제5공화국에서는 복지사회의 건설을 국정지표로 삼고 생활보호대상자들을 위한 자활지원체계를 정비하고 지원하는 방안이 모색되었지만, 자활사업의 효율성측면에서는 극복해야 할 많은 문제점이 노출되었다. 제6공화국에서는 사회복지서비스전달체계의 전문화가 시도되고 자활대상자에 대한 지원이 확대되었지만 취로사업의 축소로 자활사업은 한계에 도달하게 된다. 김영삼정부는 이러한 한계상황을 타개하기 위하여 자활공동체운동에서 자립지원에 대한 정책적 아이디어를 얻고자 생산공동체운동진영의 건의를 받아들여 생산공동체모형을 도입하고 제도화하기에 이른다. This study attempts at analyzing self-supporting policy and drawing the policy implication for new self-supporting policy by researching the history of self-supporting administration in Korea from the livelihood protection law of 1961 to the institutionalization of self-supporting program of 1996. The early relief policy of korea being started by foreign aid was institutionalized in the third republic of Korea in 1961, the sprit of self-help and self-supporting emphasized by Saemaul Movement, being precipitant on the institutionalization, has continued on without ceasing until citizen`s self-supporting campaign of the nineteen eighties. The construction of social welfare was emphasized as the goal of the fifth republic of Korea and self-supporting system for welfare recipients was organized, but many problems were found to be overcome in various aspects of self-supporting program. The specialization of social welfare delivery system was tried and the aid for welfare recipients was expanded in the sixth republic of Korea, but self-supporting program limited with the reduction of job-producing project. Kim, young-sam government tried to get ideas of self-supporting policy for the sake of improving this situation on the self-supporting community movements. The model of production community was finally introduced by its adopting suggestion of production community movement camp.