• 전자공학회논문지SC
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• 제42권3호
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• pp.11-16
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• 2005

본 논문에서는 루프 형성 기법을 이용한 새로운 IMC-PID 제어기 설계 방법을 제안하였다. 내부 안정성이 보장되고 동조 파라미터가 1개 뿐 인 IMC-PID 제어기의 동조 규칙에 루프 형성 기법을 적용함으로 이득 여유, 위상 여유, 감도함수 등의 설계 사양을 고려할 뿐 아니라 이러한 설계 사양과 설계 파라미터 사이의 관계를 유도하여 루프 이득을 얻을 수 있게 되었다. 원하는 설계 사양을 만족 시키도록 IMC-PID 제어기의 설계 파라미터 값을 선정하는 조직적 방법을 제시하고 그 유용성을 사례 연구와 분석을 통해 검토했다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.129-130
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• 2007

Self servo track writing(SSTW)은 servo track writer(STW)를 이용하지 않고 hard disk drive의 내부 VCM을 이용하여 servo track을 기록하는 방식이다. SSTW는 이전 servo track을 상대적인 reference로 하여 기록하게 되므로 초기에 발생된 error와 외부의 disturbance의 영향으로 error는 급속하게 증가된다. 이것을 radial error propagation 이라 한다. 본 논문에서는 radial error propagation을 억제하기 위한 correction signal을 설계하고 servo writing 과정에서 발생하는 disturbance의 영향을 제거하기 위하여 disturbance observer(DOB)를 add-on type으로 구성하여 tracking 제어기를 설계하였다. 또한 DOB를 적용한 경우와 유사한 gain margin, phase margin과 sensitivity function을 갖는 제어기를 설계하여 그 성능을 비교하였다. 제안된 방식은 radial error propagation을 억제 하였을 뿐만 아니라 disturbance의 최소화하여 쓰여진 track의 DC track spacing과 AC track Squeeze가 개선된 것을 모의실험을 통하여 검증하였다.

• Restorative Dentistry and Endodontics
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• 제26권1호
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• pp.64-76
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• 2001

Despite the improvements in bond strengths of dentin adhesives and resin-modified glass ionomers, the marginal seal of cervical restorations remains a concern. Microleakage at poorly sealed margins can result in staining, post-operative sensitivity, pulpal irritation, and recurrent caries. The objective of this study was to evaluate the effect of surface penetrating sealant(SPS) on the microleakage of cervical restorations. 45 extracted human teeth were selected, and Class V preparations were prepared on the both buccal and lingual surface of the teeth to the following dimensions : 1.5mm axially, 3mm mesiodistally, and 3mm incisogingivally. After cervical restoration with composite resin, compomer, glass ionomer each restoration was treated as three methods: No Tx., Scotchbond Multipurpose Adhesive$^{\circledR}$, Fortify$^{\circledR}$. The sections were examined with a stereomicroscope to determine the extent of microleakage at enamel and dentin margins. The results of this study were as follows. 1. All groups showed some microleakage. 2. Gingival cavity wall with cementum margin showed significantly higher leakage value than occlusal cavity wall with enamel margin. 3. The group treated with SPS showed significantly lower leakage value than no treated group(p<0.05). But there is no difference between Fortify$^{\circledR}$ and Scotchbond Multipurpose adhesive$^{\circledR}$. The results of this study suggest that SPS are effective in reducing microleakage of class V restorations. But it is certain that some microleakage still occurred despite the application of SPS.

• Nuclear Engineering and Technology
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• 제52권4호
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• pp.742-754
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• 2020

Zircaloy cladding oxidation is an important phenomenon for both design basis accident and severe accidents, because it results in cladding embrittlement and rapid fuel temperature escalation. For this reason during the last decade, many experts have been conducting experiments to identify the oxidation phenomena that occur under design basis accidents and to develop mathematical analysis models. However, since the study of design extension conditions (DEC) is relatively insufficient, it is essential to develop and validate a physical and mathematical model simulating the oxidation of the cladding material at high temperatures. In this study, the QUENCH-05 and -06 experiments were utilized to develop the best-fitted oxidation model and to validate the SPACE code modified with it under the design extension condition. It is found out that the cladding temperature and oxidation thickness predicted by the Cathcart-Pawel oxidation model at low temperature (T < 1853 K) and Urbanic-Heidrick at high temperature (T > 1853 K) were in excellent agreement with the data of the QUENCH experiments. For 'LOCA without SI' (Safety Injection) accidents, which should be considered in design extension conditions, it has been performed the evaluation of the operator action time to prevent core melting for the APR1400 plant using the modified SPACE. For the 'LBLOCA without SI' and 'SBLOCA without SI' accidents, it has been performed that sensitivity analysis for the operator action time in terms of the number of SIT (Safety Injection Tank), the recovery number of the SIP (Safety Injection Pump), and the break sizes for the SBLOCA. Also, with the extended acceptance criteria, it has been evaluated the available operator action time margin and the power margin. It is confirmed that the power can be enabled to uprate about 12% through best-estimate calculations.

• 에너지공학
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• 제7권1호
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• pp.65-72
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• 1998

이 논문은 극좌표이 선로조류방정식을 이용하여 전압안정성 여유전력을 평가하는 고속계산법을 제안한다. 여기서, 선로조류방정식은 상태변수 Vi, $\delta$i, Vj와 $\delta$i 그리고, 선로정수 r과 x로 구성되는데 극좌표계의 특징을 이용하면 이것은 두 개의 변수 Vi와 Vj를 가진 하나의 식이 된다. 그리고, j 모선이 조류계산에서 전압크기로 지정되는 발전기 또는 slack 모선이라면, 변수 Vi만을 가진 하나의 식 즉, {{{{ { V}`_{i } ^{2 } }}에 대한 2차 방정식으로 정식화된다. 그러므로, 전력조류다근은 간단한 계산을 통해 구할 수가 있는데 이와 같이 구해진 다근은 감도해석 또는 다근의 근접도를 통해 전압안정도를 평가할 수 가 있었다. 또한, 전압안정도 평가시에 중요한 요소인 전력용 콘덴서와 같은 조상설비를 고려하여 전압안정성 여유전력을 평가하는 방법을 개발하였다. 제안한 방법을 시험계통에 적용하여 유효성을 입증하였다.

• International journal of advanced smart convergence
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• 제8권1호
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• pp.24-34
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• 2019

In this research, a practical deep learning framework to differentiate the lesions and nodules in breast acquired with ultrasound imaging has been proposed. 7408 ultrasound breast images of 5151 patient cases were collected. All cases were biopsy proven and lesions were semi-automatically segmented. To compensate for the shift caused in the segmentation, the boundaries of each lesion were drawn using Fully Convolutional Networks(FCN) segmentation method based on the radiologist's specified point. The data set consists of 4254 benign and 3154 malignant lesions. In 7408 ultrasound breast images, the number of training images is 6579, and the number of test images is 829. The margin between the boundary of each lesion and the boundary of the image itself varied for training image augmentation. The training images were augmented by varying the margin between the boundary of each lesion and the boundary of the image itself. The images were processed through histogram equalization, image cropping, and margin augmentation. The networks trained on the data with augmentation and the data without augmentation all had AUC over 0.95. The network exhibited about 90% accuracy, 0.86 sensitivity and 0.95 specificity. Although the proposed framework still requires to point to the location of the target ROI with the help of radiologists, the result of the suggested framework showed promising results. It supports human radiologist to give successful performance and helps to create a fluent diagnostic workflow that meets the fundamental purpose of CADx.

• Asian Pacific Journal of Cancer Prevention
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• 제16권10호
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• pp.4297-4302
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• 2015

Background: To evaluate HPV testing by Hybrid Capture II (HCII) in conjunction with cytology in detecting the residual/recurrence disease after treatment of high-grade cervical intraepithelial neoplasia (CIN II-III) with loop electrosurgical excision procedure (LEEP). Materials and Methods: A retrospective review of 158 patients with histologically confirmed CIN II-III who underwent LEEP between January 2011 and October 2012 was conducted. Post-treatment control was scheduled at the 3rd, 6th, 12th and 18th month. All patients were followed up by Pap smear and HR-HPV genotype and viral load testing. Results: Pre-treatment, HR-HPV DNA, was detected in all specimens of the patients. At follow-up, 25 patients were diagnosed as the residual/recurrent disease during the FU visit, among whom, 16 patients with positive margin: 13 patients (52%) with HR-HPV DNA+/cytology+, 2 patients (8%) with HR-HPV DNA+/cytology-, 1 patient (4%) with cytology+/HR-HPV DNA-; 9 patients with clean margin - 5 patients (55.6%) with HR-HPV DNA+/cytology+; 2 patients (22.2%) with HRHPV DNA+/cytology-, 2 patients (22.2%) with cytology+/HR-HPV DNA-. None of them persisting HR-HPV DNA-/cytology-with positive or negative margin was identified as the residual/recurrent disease. The majority of residual/recurrent disease was detected at the 12th and 18th month FU, and there was almost no difference in the sensitivity and negative predictive value (NPV) between at the 3rd month and the 6th month FU visits. 14 residual/recurrence disease (14/46:30.4%) had pre-treatment high viral load (>5 000 RUL/PC) and 11 (11/112, 9.8%) with pre-treatment low viral load, P<0.05. Conclusions: (1) The persistence HR-HPV DNA is the root cause of the residual/recurrent disease for the women treated for high-grade CIN; the pre-treatment viral load and margin can be seen as the predictor. (2) The FU visit beginning at the 6th month post-treatment and lasting at least 24 months with the combination of cytology and HPV testing. (3) Patients with high pre-treatment HPV load, which is considered as one risk of developing the residual/recurrent disease, should be paid more attention (especially above 500RUL/PC) to by clinicians.

• 대한두경부종양학회지
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• 제17권1호
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• pp.42-47
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• 2001

Purpose: To evaluate the usefulness of ultrasonogram as a preoperative diagnostic tool in thyroid nodular diseases, this study was carried out. Materials and Methods: From January 1998 to December 1999, 51 patients who underwent thyroidectomy were analyzed retrospectively. We compared the finally histopathological results to ultrasonographical findings such as internal consistency, multiplicity of nodules, nodular ehogenicity, nodular capsule or margin, calcification of nodules. Results: There were 47 females and 4 males with 25 benign tumor, 23 malignant tumor and 3 occult carcinoma in histopathological diagnosis. The solid tumors in ultrasonography carried a probability of malignancy as 66.7%(16/24 cases) whereas cystic or mixed tumors as 16.7%(1/6cases) or 23.8%(5/21cases) (p=0.006). The single nodular diseases carried a high probability of malignancy as 50%(13/26cases) whereas multiple diseases as 28.6%(6/21cases). The hypoechogenicity of thyroid nodular disease showed a probability of malignancy as 60%(9/15cases) whereas mixed-echogenicity as 36.4%(4/11cases). The nodules with poorly-defined margin in ultrasonographic findings showed higher probability of malignancy as 63.6% (7/11cases) than the nodules with well -defined margin as 26.5%(9/34 cases) (p=0.025). The nodules with calcification in ultrasonographic findings were represented to high probability of malignancy as 70.6%(12/17cases) compared to those without calcification as 29.4%(10/34cases) (p=0.005). The differency between ultrasonic and histopathological diagnosis was high in solid nodules(33%), 3-4cm sized nodules (28.6%) and mixed echogenecity(27.3%) whereas low in complex nodules with cystic and solid nature(4.8%), 2-3 cm sized nodules(8.3%) and pooly defined margin(9.1%). The accuracies of sonography in differentiating malignacy from benign thyroid nodules were 7.1% of false positivity, 39.1% of false negativity, 60.9% of sensitivity, 92.9% of specificity and 78.4% of accuracy. Conclusion: Sonographic examination was relatively excellent test as a preoperative diagnostic tool in thyroid nodular diseases when detailed checklists were applied such as internal consistency, multiplicity of nodules, nodular ehogenicity, nodular capsule or margin and calcification of nodules.

• 대한두경부종양학회지
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• 제16권1호
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• pp.52-57
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• 2000

Purpose: The purpose of the study was to evaluate the sensitivity, specificity and accuracy between the FNAC and intraopevative frozen biopsy based upon the Final histologic diagnosis. Method: Authors studied 232 cases of thyroid nodule operated at Department of Surgery, College of Medicine, Chosun University, from January 1992 to December 1998. The medical records of these patients were studied retrospectively. The cytology of FNAC and the frozen section was compared to the final histologic diagnosis. 232 cases were analysed in regard to correlation of FNAC diagnosis and Intraoperative frozen section with final pathology, preoperative thyroid scan, thyroid function test, ultrasonography, final histopathology of the specimens, and surgical operation methods. 174 cases who underwent FNAC for diagnosis before operation, and Intraoperative frozen-section biopsy were classified according to whether the clinical diagnosis was benign, suspicious or malignant and evaluated the specificity sensitivity and accuracy. Result: Comparing with final histopathology, FNAC as a diagnostic test for thyroid nodules demonstrated an accuracy of 81.3%, a sensitivity of 87.5%, a specificity 86.5% with a false positivity of 2.9%, false negativity of 4.3%, respectively. and Intra-operative frozen section demonstrated an accuracy of 86.8%, a sensitivity of 87.5%, a specificity 92.1%. In the benign lesion, there was no difference in accuracy between FNAC(95.6%) and frozen section(95.1%) but, in the suspicious malignant lesion, frozen section(46.2%) was superior to FNAC(32.0%), and in the malignant disease, FNAC(97.1%) was superior to frozen section(92.3%). Conclusion: Intraoperative frozen section biopsy is useful in patients undergoing surgery for a thyroid nodule with a 'suspicious' malignant lesion and could reduce inadequate extensive excision without missing malignancy and second operation and help to determine the resection margin. It adds no information in patients with a diagnosis of malignancy following FNAC assessment and is of limited use in those in whom a benign lesion is diagnosed.

• Tuberculosis and Respiratory Diseases
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• 제44권3호
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• pp.505-515
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• 1997

배 경 : 폐암환자에서 기관지 침습에 관하여 CT의 정확도를 알아보고, 수술을 시행한 폐암환자에서 CT의 역할을 알아보기 위하여 본 연구를 시행하였다. 대상 및 방법 : 저자들은 폐절제술을 시행한 95명과 엽절제술을 시행한 61명의 수술전 CT를 분석하였다. 엽절제술을 시행 환자중 7명에서는 절제한 기관지 말단에서 암세포가 발견되어 폐절제술을 시행했다. 또한 저자들은 충분한 생검을 한 수술못한 60명의 수술전 CT도 분석하였다. 3mm 이상의 기관지벽의 비후, 불규칙한 기관지벽의 비후 그리고 기관지 직경의 감소를 기관지 침습으로 정하였다. 절제한 기관지 말단의 암세포 발견(20명), 수술한 기관지 말단에서의 폐암재발(6명) 그리고 기관지 생검상 양성(수술 안한군에서 34명)을 기관지 침습으로 생각하였다. 결 과 : 기관지 침습에 관하여 CT는 예민도 (11.5%), 낮은 양성기대치 (38%), 그러나 높은 특이도 (96%), 그리고 비교적 높은 정확도 (84%)를 나타냈으며, 수술 안한 군에서는 높은 예민도(62%), 양성 기대치를 보였다. 결 론 : 시행한 폐암환자에서 CT는 폐암의 기관지 침습에 대하여 예민도와 양성 기대치가 낮았다. 이와 같은 결과로 기관지 침습에 대한 CT의 유용성은 제한적이라 생각되며, 수술전 기관지경에 의한 기관지벽 생검이 필요하리라 생각된다.