• Journal of Korean Neurosurgical Society
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• v.40 no.1
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• pp.47-50
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• 2006

This 51-year-old man suffered from paraparesis of 1-week history. On preoperative images, spinal cord compression by infiltrative vertebral mass was shown at T3 and T4 level. Several months earlier, he underwent surgical resection of left 2nd to 4th ribs, due to painful growing chest wall mass, which was proved to be hepatocellular carcinoma. All available diagnostic procedure failed to uncover origin of malignancy. Operation was followed by adjuvant irradiation and chemotherapy to the vertebral mass, however he only to die in 3 months after operation. This is an extremely rare case of ectopic hepatocellular carcinoma at thoracic vertebrae which showed very aggressive clinical course. Possible pathogenic process is presented and discussed.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.382-382
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• 2004

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.29-37
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• 2007

In the automatic operation of an urban rail vehicle, a conventional PID control algorithm is applied to run the vehicle between stations within time limit and jerk limit. But the energy consumption in the automatic operation is much higher than in the manual operation. In this study, the optimal control algorithm for automatic operation is proposed to minimize energy consumption, which satisfies automatic operation for the urban rail vehicle, compared with the conventional PID control algorithm.

• Journal of Korean Neurosurgical Society
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• v.43 no.3
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• pp.143-148
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• 2008

Objective: Postoperative delirium (POD) is characterized by an acute change in cognitive function and can result in longer hospital stays, higher morbidity rates, and more frequent discharges to long-term care facilities. In this study, we investigated the incidence and risk factors of POD in 224 patients older than 70 years of age, who had undergone a neurosurgical operation in the last two years. Methods: Data related to preoperative factors (male gender, >70 years, previous dementia or delirium, alcohol abuse, serum levels of sodium, potassium and glucose, and co-morbidities), perioperative factors (type of surgery and anesthesia, and duration of surgery) and postoperative data (length of stay in recovery room, severity of pain and use of opioid analgesics) were retrospectively collected and statistically analyzed. Results: POD appeared in 48 patients (21.4%) by postoperative day 3. When we excluded 26 patients with previous dementia or delirium, 17 spontaneously recovered by postoperative day 14, while 5 patients recovered by postoperative 2 months with medication, among 22 patients with newly developed POD. The univariate risk factors for POD included previously dementic or delirious patients, abnormal preoperative serum glucose level, pre-existent diabetes, the use of local anesthesia for the operation, longer operation time (>3.2 hr) or recovery room stay (>90 mini, and severe pain (VAS>6.8) requiring opioid treatment (p<0.05). Backward regression analysis revealed that previously dementic patients with diabetes, the operation being performed under local anesthesia, and severe postoperative pain treated with opioids were independent risk factors for POD. Conclusion: Our study shows that control of blood glucose levels and management of pain during local anesthesia and in the immediate postoperative period can reduce unexpected POD and help preventing unexpected medicolegal problems and economic burdens.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.775-780
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• 2011

5-cell DMFC stack was fabricated and operated with the load of 4 A for 4000 hrs. After 4000 hrs operation peak power density of the stack reduced by 27.3%. Two of the five cells did now show performance degradation, the performance of other two was reduced by 40% and the performance of the other decreased by 60%. The amount of performance degradation of each cell by long-term operation did not correlate with the position in the stack. Platinum particle size in the anode catalyst layer of the MEA with the strongest degradation increased and the increase was severer on the position of methanol inlet than on the position of methanol outlet. However, platinum particle size in the cathode catalyst layers did not changed for all the MEA'. Ruthenium crossover from the anode catalyst layer to the cathode catalyst layer through the membrane was observed after 4,000 hrs operation by SEM-EDX and it occurred for all MEA' regardless of the degree of performance degradation. Atomic ratio of ruthenium to platinum in the cathode catalyst layer was the highest in the MEA with the strongest performance degradation.

• Korean Journal of Remote Sensing
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• v.36 no.6_2
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• pp.1537-1549
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• 2020

The ground sample distance of KOMPSAT-3 is 0.7 m for panchromatic band, 2.8 m for multi-spectral band, and the swath width of KOMPSAT-3 is 16 km. Therefore, an image of an area wider than the swath width (16 km) cannot be acquired with a single scanning. Thus, after scanning multiple areas in units of swath width, the acquired images should be made into one image. At this time, the necessary algorithm is called image mosaicking or image stitching, and is used for cartography. Mosaic algorithm generally consists of the following 4 steps: (1) Feature extraction and matching, (2) Radiometric balancing, (3) Seamline estimation, and (4) Image blending. In this paper, we have studied an effective seamline estimation method for satellite images. As a result, we can estimate the seamline more accurately than the existing method, and the heterogeneity of the mosaiced images was minimized.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.1
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• pp.79-85
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• 2006

This attack requires an oracle which on receipt of a ciphertext, decrypts it and replies to the sender whether the padding is VALID or INVALID. In this paper we extend these attacks to other kinds of modes of operation for block ciphers. Specifically, we apply the padding oracle attacks to multiple modes of operation with various padding schemes. As a results of this paper, 12 out of total 36 double modes and 22 out of total 216 triple modes are vulnerable to the padding oracle attacks. It means that the 12 double modes and the 22 triple modes exposed to these types of attacks do not offer the better security than single modes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.830-837
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• 2015

A study which is to develop the low-cost urban railway system for low-density line such as Gwang-ju subway Line 2 is in progress, and its TCS(Train Control System) is required as an economic system which is able to train operation suitable in low-density line. We have developed the signaling equipment which is configured with automatic block system between stations, and the control center's equipment in order to meet the requirements of TCS mentioned above. In this paper, we propose the control procedure of ATS to be required for train operation management in the low-density line such as Gwang-ju subway Line 2. The control procedure of ATS considered all features such as the requirements analysis for train operation management, the functions of train control system to be applied and the block type. Also, it considered the station(interlocking, passenger, turn-back) type, station control(stop, route, departure, turn-back departure, turn-back) type, and train operation management for exiting and entering depot. The ATS control procedure proposed in this paper has an advantage in the cost and efficiency through unification and optimization of its function. And in cost of operating and maintenance, the ATS system has a feature that can be significantly reduced.

• Journal of Chest Surgery
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• v.55 no.1
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• pp.37-43
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• 2022

Background: The surgical strategy for single-stage resection of primary colorectal cancer (CRC) and synchronous pulmonary metastases remains a matter of debate. Methods: Perioperative data of patients who underwent single-stage resection of primary CRC and synchronous pulmonary metastases were compared to those of patients who underwent 2-stage resections. The demographic data, number of metastases, type of pulmonary and colorectal resections, operation time, blood loss, postoperative complications, morbidities, mortality, medical costs, and length of hospital stay were analyzed. Results: Twenty-two patients underwent single-stage resection of primary CRC and pulmonary metastases, while 27 patients underwent 2-stage resection. Tumor size and the number of pulmonary metastases were not significantly different between the 2 groups. The extent of pulmonary metastasectomy and abdominal procedures were similar in both groups, as was the thoracic surgical approach (video-assisted thoracic surgery vs. thoracotomy). However, open laparotomy was performed more frequently in the 2-stage group than in the single-stage group (p=0.045), which also had a longer total anesthetic time (p=0.013). The operation time, medical costs, estimated blood loss, complication rates, and severity were similar in both groups, but the length of hospital stay was shorter in the single-stage group (p<0.001). Conclusion: Single-stage colorectal and pulmonary resection shortened the overall hospital stay, with no significant changes in operation time, medical costs, hospital mortality, and morbidity. Therefore, single-stage resection could be a good surgical strategy in selected patients.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.15 no.1
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• pp.5-9
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• 2004

Some patients who have undergone adenotonsillectomy (AT) or tonsillectomy(T) complain of voice change. Research was designed to determine the relationship between subjective voice change and change of parameters in boice analysis and to find the degree of voice change according to age and excised tissue volume. In 34 patients who underwent AT and 17 patients who underwent T, we measured the masalance, the fundamental frequency of /a/phonation and the formants and bandwidths of /a/, /i/, /u/ phonations. These parameters were measured preoperatively and also 7 days after the operation. Excised tissue volume was measured on operation. Postoperative changes were statistically analyzed. Any subjective voice change was asked to be reported at the visit 7 days after the operation. There was analysis for the difference of above parameters between some who answered "voice change" (A group) and the others who answered "no voice change" (B group). 24 patients(71%) who underwent AT and 4 voice change. Nasals nasalance change is an important factor in subjective voice change after AT.