• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.923-929
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• 2019

The stability of the propulsion system is crucial for the autonomous vessel. Multiple power generation and propulsion systems should be provided for the stability of the propulsion system. High power generation capacity is calculated for stability, resulting in economical decline due to low load operation. To solve this problem, we need to optimize the power system. In this paper, an OPMS for electric propulsion ship is constructed. The OPMS consists of a hybrid power generation system, an energy storage system, and a control load system. The power generation system consists of a dual fuel engine, the energy storage system is a battery, and the control load system consists of the propulsion load, continuous load, intermittent load, cargo part load and deck machine load. The power system was constructed by modeling the characteristics of each system. For the experiment, a scenario based on ship operation was prepared and the stability and economical efficiency were compared with existing electric propulsion ships.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.92-101
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• 2023

To solve the problem of climate change, carbon neutrality has now become a necessity rather than an option. Hydrogen is not only a energy storage that can supplement the intermittent production of renewable energy, but is also considered a good alternative in the field of utilization as it does not emit carbon dioxide after reaction. In order to revitalize hydrogen vehicles, one of the fields of hydrogen utilization, the construction of hydrogen station infrastructure must be preceded. Prioritization of risk factors is necessary for efficient operation and risk assessment of hydrogen stations, but due to the short operation period of domestic hydrogen stations, there is a lack of frequency data on accidents and their reliability is low. In this study, we aim to identify the causes and consequences of deviations in hydrogen stations through HAZOP analysis. Additionally, we intend to analyze them using Fuzzy-AHP. Through this, we intend to derive the decision values for the causes of deviations in hydrogen stations and apply them to hydrogen accident cases and risk assessments to confirm the reliability and utility of the data.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.2
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• pp.133-144
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• 1995

After resection of intraarticular, periacetabulum(P2) and pubic rami(P23) and extraarticular, proximal femur(P2-H12) by Enneking classification, reconstruction is very difficult. We experienced three cases of saddle prostheses for reconstruction after P2, P23, and P2-H12 resection in pelvic malignancies. Case 1 was a high grade chondrosarcoma in 36 year-old-man and P2 resection was done. But he died of disease 19 months after operation. Case 2 was a malignant giant cell tumor in 32 year-old-woman. P23 resection was given and she is disease-free 32 months after operation. Case 3 was an osteosarcoma of 27-year-old-man and P2-H12 resection was performed and he is disease-free postoperative 12 months now. According to MSTS functional evaluatin system, all three patients showed no pain(5), intermediate function(2), emotinally satisfied(3), one cane or crutch supported(1), limited walking(3), and minor cosmetic gait(3). There was no significant complication and no dislocation except intermittent inguinal hernia in case 2. All patients started crutch walking 3 weeks after operation. Around 6 months postoperatively, the preserved iliac wing(P1 component) was hypertrophied enough to endure the full weight bearing. All could have squating and kneeling positions. In conclusion, saddle prosthesis would be a very useful method of reconstruction after P2, P23, and/or H1-2 resection to shorten the operation time and to reduce the infection rate without significant loss of function.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.1-9
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• 2019

In the recent marine sector, the development and standardization regarding S-100, which is the universal hydrographical data model standard for development of marine space information, was progressed, and for the effectiveness of marine chart production work and the multi-purpose use of water level data in S-100, S-102(Bathymetric Surface grid) standard development and various studies of BAG formats combined with water level and uncertainty, property information is being progressed. Since the water level information that is important in the operation of the ship is provided based on S-102, the calibration method of the location information when producing S-102 is an important factor in deciding the water level. In this study, the hydrographical surveying was conducted by piloting the standardized method for the production of S-102 in Korea, and have compared the accuracy of water level information according to the GNSS post treatment calibration method. As a result of comparing the water level in 2 places in the rocky terrain of the study area, the northern water level of Namu-do was shown as DL 0.79~0.83m, the eastern water level of Daeho-do was DL 12.63~12.91m, and the horizontal position errors of the intermittent sunshine water level were confirmed to be within 1m. As a result, the intermittent sunshine water level according to the location calibration method when producing the BAG was confirmed that it was in the available range for a ship's safe voyage. However, the accuracy verification for the location of the ship when conducting hydrographical surveying was judged that there is a need for a various additional study about regional characteristics and environment factor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.662-671
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• 2020

Recently, for the purposes of reducing carbon dioxide(CO₂) emissions in the island area, countermeasures to decrease the operation rate of diesel generator(DG) and to increase one of renewable energy sources(RES) is being studied. In particular, the demonstration and installation of stand-alone micro-grid(MG) system which is composed of DG, RES and energy storage system(ESS) has been implemented in some island areas such as Gapa-do, Gasa-do and Ulleung-do island. However, many power quality(PQ) problems may be occurred due to an intermittent output of RES including photovoltaic(PV) system and wind power(WP) system in a normal operating of constant voltage & constant frequency(CVCF) inverter-based MG system. Therefore, this paper presents a modeling of the 30kW scale MG system using PSCAD/EMTDC, and also implements a 30kW scale CVCF inverter-based MG system as test devices to analyze normal operating characteristics of MG system. From the simulation and test results, it is confirmed that the proposed methods are useful and practical tools to improve PQ problems such as under-voltage, over-voltage and unbalanced load in CVCF inverter-based MG system.

• Journal of Gastric Cancer
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• v.1 no.1
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• pp.38-43
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• 2001

Purpose: Roux stasis syndrome is the main complication of a Roux-en-Y gastrojejunostomy. The aim of this study was to compare the occurrence rate of Roux stasis syndrome with the passing of time in a conventional Roux-en-Y gastrojejunostomy and in an uncut Roux-en-Y gastrojejunostomy. Materials and Methods: 50 patients (31 men and 19 women) had a conventional Roux-en-Y reconstruction and 53 patients (35 men and 18 women) had an uncut Roux-en-Y reconstruction. The Roux stasis syndrome was defined by clinical criteria only. The criteria included one of the four following conditions at the time of follow-up: chronic upper abdominal pain, postprandial fullness, persistent nausea, and intermittent vomiting that are worsened by eating. Follow-up after surgery was done in all patients at $7\∼12,\;13\~18,\;19\~24,\;25\~30$, and $31\∼36$ months. Results: According to the criteria, the Roux stasis syndrome occurred in 40.0$\%$ of the patients at 7$\∼$12 months, 33.3$\%$ at $13\∼19$ months, $35.3\%$ at $19\∼24$ months, $32.0\%$ at $25\~30$ months, and $33.3\%$ at $31\∼36$ months after a conventional Roux-en-Y operation. The syndrome occurred in $22.6\%$ of the patients at $7\∼12$ months, $15.2\%$ at $13\∼18$ months, $17.1\%$ at $19\∼24$ months, $19.2\%$ at $25\∼30$ months, and $20\%$ at $31\∼36$ months after an uncut Roux-en-Y reconstruction. Conclusion: In terms of occurrence pattern, only a little variance existed one year after both procedures. Comparing the Roux stasis syndrome in both procedures, the uncut Roux operation had better results than the conventional Roux operation.

• The Korean Journal of Pain
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• v.28 no.3
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• pp.210-216
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• 2015

Background: Infusion methods during regional analgesia using perineural catheters may influence the quality of postoperative analgesia. This study was conducted to compare the effects of combined or bolus-only infusion of 0.2% ropivacaine on the postoperative analgesia in interscalene brachial plexus block (ISBPB) with perineural catheterization. Methods: Patients scheduled for arthroscopic rotator cuff repair were divided into two groups, one that would receive a combined infusion (group C, n = 32), and one that would receive intermittent infusion (group I, n = 32). A perineural catheter was inserted into the interscalene brachial plexus (ISBP) using ultrasound (US) and nerve stimulation, and 10 ml of 0.2% ropivacaine was administered. After the operation, group C received a continuous infusion of 4 ml/h, and a 4 ml bolus with a lockout interval of 60 min. Group I received only a 4 ml bolus, and the lockout interval was 30 min. Postoperative pain by the numeric rating scale (NRS) and the forearm muscle tone by the manual muscle test (MMT) were checked and evaluated at the following timepoints: preoperative, and postoperative 1, 4, 12, 24, 36, and 48 h. Supplemental opioid requirements, total consumed dose of local anesthetic, and adverse effects were compared between the two groups. Results: Sixty-four patients completed the study and the postoperative values such as operation time, time to discharge, and operation site were comparable. There were no differences in NRS scores and supplemental opioid requirements between the two groups. The MMT scores of group I at 4 and 12 h after surgery were significantly higher than those of group C (P < 0.05). The total consumed dose of local anesthetic was significantly lower in group I than in group C (P < 0.05). The adverse effects were not different between the groups. Conclusions: The bolus-only administration of 0.2% ropivacaine provided a similar analgesic effect with a lower total volume of local anesthetic and decreased motor weakness compared to combined infusion. Therefore, bolus-only administration is an effective postoperative analgesic method in ISBPB with perineural catheterization after rotator cuff repair.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.1
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• pp.41-48
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• 2016

Motor evoked potential of spinal surgery is known to cause damage due to the movement path of the continuous scan operation and surgery can be performed with minimized disability after surgery. However, if it is not at all formed at the wave motion evoked potential can occur during surgery and, in some cases the size of the waveform to be measured is very small and intermittent. In this case, the surgery cannot provide information about whether there is neurological damage. Increased intensity of the wave-induced motion of the dislocation does not occur if it appears in a very small amplitude stimulus, but changing the inspection area that electrical stimulation of the waveform changes could not be found. However, stimulation of a wide area in the cerebral cortex was found to occur with a waveform in the patients who underwent examination. Through this study, we propose a useful motor evoked potential test. From November to December 2015 three spine surgery patients visited Samsung Medical Center as neurosurgery patients with omission discomfort, gait disturbance, and no symptom of strength before surgery. In spine surgery patients with motor grade weakness, when motor evoked potential waveform has not been measured, in examination of the site of electrical stimulation of the cerebral cortex from entering the C3+C5/C4+C6 or C3+C1/C4+C2 if by the activity of more motor neuron unit, it was found that the waveform is better formed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.5
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• pp.422-427
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• 2004

Treacher Collins syndrome is inherited as an autosomal dominant trait with variable penetrance. It shows a marked variability even in the same family. This syndrome is developmental defect affecting the branchial arches. It is not usually associated with acute respiratory distress, but has symptoms of microtia, hypoplastic zygomatic bones, hypoplastic mandibular rami, and bilateral coloboma. It usually requires an emergency operation immediately after the birth. We experienced an infant with Treacher Collins syndrome who showed retrognathia, glossoptosis, microtia, and cleft palate. Intermittent cyanosis, depression of the chest, respiratory difficulty associated with airway obstruction, and swallowing difficulty were also observed. To relieve severe upper airway obstruction caused by retrognathia and glossoptosis, we simultaneously performed tongue-lip adhesion and subperiosteal release of the floor of the mouth. The respiratory and swallowing difficulties were relieved and the tongue repositioned anteriorly. We report the present case with a review of the literature.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.73-78
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• 1992

- Enzymatic synthesis of L-tryptophan(Trp) using E. coli tryptophanase has been investigated. In order to reduce the substrate inhibition by indole and to increase the product yield of L-tryptophan three different approaches have been made in this work. First, indole was intermittently fed to the reaction mixture in order to control the indole concentration at lower level. When 15 mM of indole was used as a total amount of substrate, conversion yield of 80% has been obtained with intermittent feeding while only 20% of indole was converted into L-tryptophan by conventional batch operation, The second method employed in this work was the use of cyclohexane-phosphate buffer organic two-phase system. In this system, indole was mainly partitioned into the organic-solvent phase and therefore substrate inhibition was expected to be reduced. L-Tryptophan production in organic two-phase system was, however, unexpectedly lower than that obtained in aqueous buffer solution. As a third method cyclodextrins have been added to the aqueous reaction mixture. It was found that the addition of $\beta$-cyclodextrin enhanced the tryptophan synthesis noticeably while $\alpha$-cycfodextrin showed little effect on tryptophan production.