• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.6
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• pp.1099-1110
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• 2023

The recognition system of autonomous driving and robot navigation performs vision work such as object recognition, tracking, and lane detection after multi-sensor fusion to improve performance. Currently, research on a deep learning model based on the fusion of a camera and a lidar sensor is being actively conducted. However, deep learning models are vulnerable to adversarial attacks through modulation of input data. Attacks on the existing multi-sensor-based autonomous driving recognition system are focused on inducing obstacle detection by lowering the confidence score of the object recognition model.However, there is a limitation that an attack is possible only in the target model. In the case of attacks on the sensor fusion stage, errors in vision work after fusion can be cascaded, and this risk needs to be considered. In addition, an attack on LIDAR's point cloud data, which is difficult to judge visually, makes it difficult to determine whether it is an attack. In this study, image scaling-based camera-lidar We propose an attack method that reduces the accuracy of LCCNet, a fusion model (camera-LiDAR calibration model). The proposed method is to perform a scaling attack on the point of the input lidar. As a result of conducting an attack performance experiment by size with a scaling algorithm, an average of more than 77% of fusion errors were caused.

• Radiation Oncology Journal
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• v.24 no.2
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• pp.123-127
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• 2006

Purpose: The purpose of this study was to investigate the clinical findings, treatment, and outcome of patients with glassy cell carcinoma of cervix. Materials and Methods: We reviewed all cases of glassy cell carcinoma of the uterine cervix confirmed and treated at the Dongsan Medical Center, Keimyung University, between January 1993 and December 2005. There were 7 cases with histopathologically confirmed gassy cell carcinoma. A tumor was diagnosed as glassy cell carcinoma if over 50% of the tumor cell type displayed glassy cell features. Six patients with stage IB had radical hysterectomy and bilateral pelvic node dissection, and 2 of them received adjuvant external pelvic irradiation with concurrent chemotherapy. Remaining one patient with stage IIA had curative concurrent chemoradiotherapy with external pelvic irradiation and brachytherapy. Results: There were 7 patients diagnosed as glassy cell carcinoma among the 3,745 (0.2%) patients of carcinoma of uterine cervix. The mean age of 7 patients was 44 years with range of 35 to 53 years of age. The most frequent symptom was vaginal bleeding (86%). By the punch biopsy undertaken before treatment of 7 cases, 2 only cases could diagnose as glassy cell carcinoma of uterine cervix, but remaining of them confirmed by surgical pathological examination. The mean follow up duration was 73 months with range of 13 to 150 months. All 7 patients were alive without disease after treatment. Conclusion: Glassy cell carcinoma of the uterine cervix is a distinct clinicopathologic entity that demonstrates an aggressive biologic behavior. However for early-stage disease, we may have more favorable clinical outcome with radical surgery followed by chemoradiothery.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.98-102
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• 2018

Purpose When examining patients with digestive system Leakage, it is not easy to distinguish between bile leakage and bleeding only with Planar images. I would like to evaluate the utility of leakage of bile, confirmation of gastrointestinal bleeding and location discrimination using SPECT-CT. Materials and Methods SPECT-CT was performed according to the request of the reading room after acquiring Planar image for a total of 13 patients, including 8 patients suspected of bile leakage and 5 patients suspected of gastrointestinal bleeding, among patients visiting this specification went. We used Symbia T16 from SIEMENS and Discovery 670 from GE. Planar and SPECT-CT images were evaluated with a score of 1 to 10 by 4 experienced nuclear medicine doctors. Using the sensitivity and the specificity, the evaluation of the inspection by the ROC curve was carried out. The final diagnosis was confirmed by follow-up observation as a result of reoperative surgery. Results The sensitivity, specificity and accuracy of SPECT-CT were 91.7%, 100% and 94.2%, respectively. Planar images were 83.3%, 68.8% and 78.8%, respectively. Planar images showed lower diagnostic accuracy compared to SPECT-CT (78.8%, 94.2%, p<0.05). Moreover, the reliability of the diagnosis of SPECT-CT by ROC curve analysis showed a more useful result than the Planar image (p<0.05). Conclusion SPECT-CT had high sensitivity and specificity for diagnosis of biliary leakage and gastrointestinal bleeding and location discrimination. When SPECT-CT is additionally performed together with Planar images, it may be considered to improve bile leakage and diagnosis of gastrointestinal bleeding patients and position discrimination evaluation. There is usefulness depending on the patient's age and position, but consideration of additional CT exposure may be done sufficiently.

• The Korean Journal of Nuclear Medicine Technology
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• v.24 no.1
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• pp.20-26
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• 2020

Purpose It is intended to figure out the errors derived from changes in depth and volume when measuring the Standard source and ^99mTc-pertechnetate by using a Dose calibrator. Then recommend appropriate measurement depth and volume. Materials and Methods As a Dose calibrator, CRC-15βeta and CRC-15R (Capintec, New Jersey, USA) was used, and the measurement sources were ⁵⁷Co, ¹³³Ba, ¹³⁷Cs and ^99mTc-pertechnetate was also adopted due to its high frequency of use. The Standard source was respectively measured the changes according to its depth without changing the volume, in a range of 0 cm to 15 cm from the bottom of the ion chamber. ^99mTc-pertechnetate was measured at each depth by changing the volume with 0.1 mL, 0.3 mL, 0.5 mL, 0.7 mL and 0.9 mL Respectively. And the depth range was from 0 cm to 15 cm at the bottom of the ion chamber. Results In the case of Standard source ⁵⁷Co, ¹³³Ba, ¹³⁷Cs and ^99mTc-pertechnetate, there were significant differences according to the measurement depth(p<0.05). ^99mTc-pertechnetate has a negative correlation coefficient according to the depth, and the error of the measured value was negligible at a depth from 0 cm to 7 cm at 0.3 mL and 0.5 mL, and the range of error increased as the volume increased. Conclusion In clinical practice, it is sometimes installed differently than the Standard depth recommended by the equipment company. If it's measured at the recommended depth and volume, it could be thought that unnecessary exposure of the operator and the patient will be reduced, and more accurate radiation exams will be possible in quantitative analysis.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.591-597
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• 2008

Background: Pulmonary endarterectomy is widely accepted as a treatment for chronic thromboembolic pulmonary hypertension. Based on our experiences, we sought to find ways to reduce perioperative complications and to improve surgical outcomes in patients undergoing pulmonary endarterectomy. Material and Method: This study was designed as a retrospective analysis of 20 patients with pulmonary hypertension who underwent pulmonary endarterectomy between January 1998 and March 2008. All patients presented with chronic dyspnea. Deep vein thrombosis (DVT) was the major cause of chronic pulmonary thromboembolism (55%). Seventeen patients (85%) underwent inferior vena cava (IVC) filter placement. Thirteen patients underwent surgery under total circulatory arrest, while the others underwent surgery while on low flow cardiopulmonary bypass. Concomitant tricuspid annuloplasty was done in 6 patients (66%) whose tricuspid regurgitation was as severe as grade IV/IV. The mean follow-up duration was $45{\pm}32$ months. Result: Using of University of California, San Diego (UCSD), thromboembolism classification, 4 patients (20%) were type 1, 8 patients (40%) were type II, and 8 patients (40%) were type III. Right ventricular systolic pressure was reduced significantly from $77{\pm}29$ mmHg to $37{\pm}19$ mmHg after pulmonary endarterectomy (p<0.001). The degree of tricuspid regurgitation and the NYHA functional class were all improved postoperatively. Reperfusion edema occurred in 7 cases (35%). The incidence of reperfusion edema was higher in the UCSD type III group than in the other group (25% vs 50%, p=0.25) and the length of postoperative intensive care unit stay was longer in type III group ($5{\pm}2$ days vs $9{\pm}7$ days, p=0.07). The early mortality rate was 10%, and the late mortality rate was 15% (n=3); one death was due to progression of underlying non-Hodgkin's lymphoma, and the other deaths were related to recurrent thromboembolism and persistent pulmonary hypertension, respectively. Conclusion: Pulmonary endarterectomy, as a curative surgical method for treating chronic thromboernbolic pulmonary hypertension, should be performed aggressively in patients diagnosed with chronic thromboembolic pulmonary hypertension, and an effort should be made to reduce the frequency of perioperative complications and to improve surgical outcomes.

• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.31-39
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• 2016

Background: It is necessary to consider the overall countermeasure for analysis of nuclear activities according to the increase of the nuclear facilities like nuclear power and reprocessing plants in the neighboring countries including China, Taiwan, North Korea, Japan and South Korea. South Korea and comprehensive nuclear-test-ban treaty organization (CTBTO) are now operating the monitoring instruments to detect radionuclides released into the air. It is important to estimate the origin of radionuclides measured using the detection technology as well as the monitoring analysis in aspects of investigation and security of the nuclear activities in neighboring countries. Materials and methods: A three-dimensional forward/backward trajectory model has been developed to estimate the origin of radionuclides for a covert nuclear activity. The developed trajectory model was composed of forward and backward modules to track the particle positions using finite difference method. Results and discussion: A three-dimensional trajectory model was validated using the measured data at Chernobyl accident. The calculated results showed a good agreement by using the high concentration measurements and the locations where was near a release point. The three-dimensional trajectory model had some uncertainty according to the release time, release height and time interval of the trajectory at each release points. An atmospheric dispersion model called long-range accident dose assessment system (LADAS), based on the fields of regards (FOR) technique, was applied to reduce the uncertainties of the trajectory model and to improve the detective technology for estimating the radioisotopes emission area. Conclusion: The detective technology developed in this study can evaluate in release area and origin for covert nuclear activities based on measured radioisotopes at monitoring stations, and it might play critical tool to improve the ability of the nuclear safety field.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.3-14
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• 2006

Music summarization means a technique which automatically generates the most importantand representative a part or parts ill music content. The techniques of music summarization have been studied with two categories according to summary characteristics. The first one is that the repeated part is provided as music summary and the second provides the combined segments which consist of segments with different characteristics as music summary in music content In this paper, we propose and evaluate two kinds of music summarization techniques. The algorithm using multi-level vector quantization which provides a repeated part as music summary gives fixed-length music summary is evaluated by overlapping ration between hand-made repeated parts and automatically generated summary. As results, the overlapping ratios of conventional methods are 42.2% and 47.4%, but that of proposed method with fixed-length summary is 67.1%. Optimal length music summary is evaluated by the portion of overlapping between summary and repeated part which is different length according to music content and the result shows that automatically-generated summary expresses more effective part than fixed-length summary with optimal length. The cluster-based algorithm using 2-D similarity matrix and k-means algorithm provides the combined segments as music summary. In order to evaluate this algorithm, we use MOS test consisting of two questions(How many similar segments are in summarized music? How many segments are included in same structure?) and the results show good performance.

• Journal of Chest Surgery
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• v.35 no.4
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• pp.274-282
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• 2002

Background: Paravalvular leakage or false aneurysm developed after isolated aortic valve replacement(AVR) for aortic regurgitation(AR) associated with Behcet's disease is one of the most serious complications, and requires subsequent reoperations. We describe the surgical result of homograft aortic root replacement(ARR) for AR associated with Behcet's disease. Material and Method: From January 1992 to December 2001, 6 patients with AR associated with Behcet's disease underwent 7 ARR with homograft and 1 Ross operation. Five patients were male and one was female. The grafts used for ARR were 5 aortic and 2 pulmonic homografts. Ages at operation ranged from 27 to 51 years(mean, 37$\pm$9 years). Two patients underwent ARR with aortic homograft at the first operation. In the remaining 4 patients, ARR using a homograft was performed for paravalvular leakage that developed after AVR, and the mean interval from AVR to ARR was 21 $\pm$29 months(range, 5 to 73.3 moths, median, 7.6 months). Result: There was no early death. All patients were followed up for an average of 18.9$\pm$24.0 months(range, 1.9 to 68.9 months, median, 8.4 months). Two of 4patients who had undergone ARR after AVR required subsequent reoperations for false aneurysm of the ascending aorta and failure of pulmonary homograft. One patient underwent re-replacement of the aortic root, ascending aorta and partial aortic arch with an aortic homograft, the other underwent Ross operation. Conclusion: This study suggests that aortic root replacement using a homograft in aortic regurgitation with Behcet's disease may provide good clinical results and decrease the incidence of paravalvular leakage or false aneurysm after aortic valve replacement. However, the adequate perioperative management and complete removal of the inflarrunatory tissue at operation were also important for the good long-term results.

• Journal of Gastric Cancer
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• v.9 no.4
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• pp.246-255
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• 2009

Purpose: The objectives of this study were to investigate the impact of the number of resected lymph nodes on the survival of gastric cancer patients who underwent curative resection, and to evaluate the cut-off values that can have an influence on survival on the tumor stage-stratified analysis. Materials and Methods: The subjects were 949 gastric cancer patients who underwent curative resection at Korea University Medical Center from 1992 to 2002. They were classified according to the depth of tumor invasion, and the influence of the number of resected lymph nodes on survival was investigated. The cut-off value for the number of resected lymph nodes was determined as the smallest value that showed a significant survival difference. Results: The tumor size, location, lymph node stage, the number of metastatic lymph nodes and the number of resected lymph nodes were significantly different according to the tumor stage. The average number of resected lymph nodes was about 39, and it showed linear correlation with the number of metastatic lymph nodes. On the Cox proportional hazard model, the cut-off values of the number of resected lymph nodes, as corrected by the number of metastatic lymph nodes, was 14 for all the patients, 15 for the pT1 patients, 28 for the pT2 patients and 37 for the pT3 patients, respectively. Conclusion: Retrieving a number of lymph nodes that is more than the cut-off value could improve the survival of gastric cancer patients. Surgeons should also make efforts to perform an exact and thorough D2 lymph node dissection. Therefore, we urge surgeons to perform D2 dissection and pathologists should examine an certain exact number of lymph nodes.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.6
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• pp.526-534
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• 2009

Purpose: We retrospectively investigated the diagnostic performance of $^{18}F$-fluorodeoxyglucose positron emission tomography (PET) and PET/CT for cancer detection in asymptomatic health-check examinees. Materials and Methods: This study consisted of 5091 PET or PET/CT conducted as part of annual health examination at one hospital from March 1998 to February 2008. To find the incidence of cancers, medical records of the subjects were thoroughly reviewed for a follow-up period of one year. The patterns of formal readings of PET and PET/CT were analyzed to assess the sensitivity and specificity for cancer detection. The histopathology and stage of the cancers were evaluated in relation to the results of PET. Results: Eighty-six cancers (1.7%) were diagnosed within one year after PET or PET/CT. When PET and PET/CT results were combined, the sensitivity was 48.8% and specificity was 81.1% for cancer detection. PET only had a sensitivity of 46.2% and a specificity of 81.4%, and PET/CT only had a sensitivity of 75.0% and a specificity of 78.5% respectively. There were no significant differences in cancer site, stage and histopathology between PET positive and PET negative cancers. In 19.3% of formal readings of PET and PET/CT, further evaluation to exclude malignancy or significant disease was recommended. Head and neck area and upper gastrointestinal tract were commonly recommended sites for further evaluation. Conclusions: PET and PET/CT showed moderate performance for detecting cancers in asymptomatic adults in this study. More experience and further investigation are needed to overcome limitations of PET and PET/CT for cancer screening.