• Archives of Craniofacial Surgery
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• v.18 no.3
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• pp.197-201
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• 2017

Maxillary sinus mucocele can occur due to many medical factors such as chronic infection, allergic sinonasal disease, trauma, and previous surgery. However, it occurs mainly after Caldwell-Luc operation, usually more than 10 years after surgery. There are a few cases of maxillary sinus mucocele with ocular symptoms. Also, a case causing ocular symptoms because of invasion to the orbital floor is rare. Therefore, we report a case of a 55-year-old male patient who underwent Caldwell-Luc operation about 30 years ago. Then, symptoms such as exophthalmos, diplopia, and visual disturbance developed suddenly 3 months prior to admission. Computed tomography showed a cyst invading the orbital floor which resulted in eyeball deviation. The orbital floor defect measured approximately $2.5{\times}3.3cm$. Maxillary sinus mucocele was removed through an endoscopic approach. After this, we reconstructed the orbital floor through a subciliary incision. Observation was carried out after three years, and ocular symptoms such as diplopia and exophthalmos did not recur.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1265-1274
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• 2018

This paper proposes a virtual flux (VF) and positive-sequence power based control strategy to improve the performance of grid-interfaced three-phase voltage source converters against unbalanced and distorted grid conditions. By using a second-order generalized integrator (SOGI) based VF observer, the proposed strategy achieves an AC voltage sensorless and grid frequency adaptive control. Aiming to realize a balanced sinusoidal line current operation, the fundamental positive-sequence component based instantaneous power is utilized as the control variable. Moreover, the fundamental negative-sequence VF feedforward and the harmonic attenuation ability of a sequence component generator are employed to further enhance the unbalance regulation ability and the harmonic tolerance of line currents, respectively. Finally, the proposed scheme is completed by combining the foregoing two elements with a predictive direct power control (PDPC). In order to verify the feasibility and validity of the proposed SOGI-VFPDPC, the scenarios of unbalanced voltage dip, higher harmonic distortion and grid frequency deviation are investigated in simulation and experimental studies. The corresponding results demonstrate that the proposed strategy ensures a balanced sinusoidal line current operation with excellent steady-state and transient behaviors under general grid conditions.

• Journal of Chest Surgery
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• v.23 no.3
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• pp.572-576
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• 1990

A complete transection of left main bronchus was repaired by end to end anastomosis 5 months after the chest trauma in the Yeungnam University Hospital. The patient was a 36 years old male who had been injured bluntly by a heavy package on the left chest. The initial symptoms and signs were dyspnea, chest pain and subcutaneous emphysema on the left neck, but on admission at our hospital his chief complaint was only mild left chest discomfort. The preoperative chest X-ray findings 5 months after the trauma revealed total collapse of the left lung, deviation of trachea to the left, elevation of left diaphragm, abrupt discontinuation in the course of an air-filled left main bronchus and bronchoscopy showed that the left main bronchus was completely occluded, without any signs of inflammation, approximately 4 cm from the carina. The operation was performed through standard posterolateral thoracotomy incision at the fifth intercostal space. There was not any suppuration within the transected lung but plenty of white mucus which was removed by forceful suction. The transected bronchial edges were debrided and anastomosed primarily by end to end with interrupted nonabsorbable sutures. The suture line was reinforced with a pleural flap. The postoperative course was uneventful and pulmonary function following operation improved progressively and proved the delayed repair to have a reasonable decision.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.2
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• pp.75-81
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• 2021

This study analyzes the resonance characteristics caused by the mutual interference between LCL filters and the grid impedance under the parallel operation of the grid-connected inverter using the LCL filter. These characteristics are verified through simulation and experiment. Two inverters are used to connect to the grid in parallel, and the system parameters, including the LCL filter, are set to the same conditions. In the case of inverters running in parallel at the point of common coupling, the presence of grid impedance causes mutual interference between the LCL filters of each inverter, and the deviation of the filter resonance frequency is analyzed to understand the parallel inverter. The correlation between the number of devices and the size of grid impedance is simulated by PSIM and verified by MATLAB. By connecting the real-time digital simulator Typhoon HILS to the DSP 28377 control board, the mutual interference characteristics are tested under the condition of two inverters running in parallel. The experimental and analysis results are the same, indicating the validity of the analysis.

• New & Renewable Energy
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• v.16 no.4
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• pp.41-48
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• 2020

This study performed a single hole operation method using a balancing well-cross-mixed underground heat exchanger, and conducted thermal performance studies of an SCW-type underground heat exchanger using a two-well. The study attempted to change the existing operating method of the two adjacent SCW underground heat exchangers with one ball each. The SCW-type geothermal heat exchanger is considered to enable up to 20% of bleed discharge at maximum load, which makes groundwater usage unequal. The efficiency factor of the geothermal system was improved by constructing the discharged water by cross-mixing two balancing wells to prevent the discharge of groundwater sources and keep the temperature of the underground heat exchanger constant. As a result of the cooling and heating operation with the existing SCW heat exchange system and the balancing well-cross-mixed heat exchange system, the measured performance coefficient improved by 23% and 12% in cooling and heating operations, respectively. In addition, when operating with a balanced cross-mixing heat exchange system, it has been confirmed that the initial basement temperature is constant with a standard deviation of 0.08 to 0.12℃.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.392-400
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• 2011

Purpose: Cleft lip and palate is one of the most frequent hereditary deformities of the maxillofacial region which can arise in facial and jaw abnormalities as well as malocclusion and speech problems. In particular, unilateral cleft lip and palate is characterized by midface deformity resulting in maxillary anterior nasal septal deviation and nasal deformity. The aim of this study is to analyze the facial deformity of untreated unilateral cleft lip patients for contribution to primary cheiloplasty. Methods: Thirty-three patients with unilateral cleft lip and palate were impressioned before operation and facial casts were made. The casts were classified into complete cleft lip and incomplete cleft lip groups and each group were classified into affected side and normal side. Anthropometric reference points and lines were setted up and analysis between points and lines were made. Results and Conclusion: The obtained results were as follows: 1. The intercanthal width had no significant difference between the incomplete and complete cleft lip groups. 2. Cleft width and alar base width were greater in the complete group, and nasal tip protrusion was greater in the incomplete group. 3. Involved alar width and nostril width were greater in the complete group and in both complete and incomplete groups, involved alar width and nostril width were greater than the non-involved side. 4. The lateral deviation of the subnasale was greater in the complete group in both involved and non-involved sides. 5. The nasal laterale was placed inferiorly in both cleft groups. 6. The subnasale was deviated to the non-involved side in both cleft groups. 7. The nose tip was deviated to the non-involved side in both cleft groups and had greater lateral deviation in the complete cleft group. 8. The midpoint of cupid's bow had no vertical difference between complete and incomplete groups, but had a greater lateral deviation in the complete group. 9. In the complete cleft group, correlation between differences in cleft width and nostril width and columella height difference were obtained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.523-532
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• 2008

In this paper, we proposed a U-shaped RFID tag antenna with isotropic radiation characteristic for the stable operation of RFID system. The proposed antenna is composed of a U-shaped half wavelength dipole and a rectangular-shaped feed. In order to have good impedance matching with a tag chip, the commercial tag chip is attached to the lower center of the feed. A gain deviation characteristic of the U-shaped tag antenna can be further improved by inserting a rectangular slit in the lower center of the U-shaped antenna body. On the condition of VSWR<2, the tag antennas of two structures satisfy the Korea UHF RFID bandwidth and showed the gain deviation of less than 1.63 dB and 0.74 dB for without slit and with slit, respectively. On the condition of VSWR<5.8, the U-shaped tag antenna showed the gain deviation of less than 3.8 dB and 1.2 dB for without slit and with slit, respectively.

• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2452-2459
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• 2020

Neutron spectrum is essential to the safe operation of reactors. Traditional online neutron spectrum measurement methods still have room to improve accuracy for the application cases of wide energy range. From the application of artificial neural network (ANN) algorithm in spectrum unfolding, its accuracy is difficult to be improved for lacking of enough effective training data. In this paper, an adaptive deviation-resistant neutron spectrum unfolding method based on transfer learning was developed. The model of ANN was trained with thousands of neutron spectra generated with Monte Carlo transport calculation to construct a coarse-grained unfolded spectrum. In order to improve the accuracy of the unfolded spectrum, results of the previous ANN model combined with some specific eigenvalues of the current system were put into the dataset for training the deeper ANN model, and fine-grained unfolded spectrum could be achieved through the deeper ANN model. The method could realize accurate spectrum unfolding while maintaining universality, combined with detectors covering wide energy range, it could improve the accuracy of spectrum measurement methods for wide energy range. This method was verified with a fast neutron reactor BN-600. The mean square error (MSE), average relative deviation (ARD) and spectrum quality (Qs) were selected to evaluate the final results and they all demonstrated that the developed method was much more precise than traditional spectrum unfolding methods.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.80-90
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• 2022

Purpose: The objective of this study was to improve smart monitoring and monitoring management technology in long tunnels by investigating and analyzing the normal operation rates of monitoring hardware in the long tunnels of high-speed and urban railways. Method: This study evaluated, analyzed, and compared the normal operation rate of 6-8 types of monitoring hardware for each long tunnel, targeting three high-speed railway lines with a long tunnel (i.e., Suseo-Pyeongtaek Line, Gyeongbu Line, and Honam Line) and two urban railway groups with a long tunnel (i.e., Seoul Metro Lines 5, 6, and 7, and 9). Result: The rank of the normal operation rate of monitoring hardware was in the order of Suseo-Pyeongtaek High-Speed Railway (92.1%), Seoul Metro Lines 5, 6, and 7 (85.8%), Seoul Metro Line 9 (85.2%), Gyeongbu High-speed Railway (80.5%), and Honam High-speed Railway (46.7%). Conclusion: The mean normal operation rate of the monitoring hardware in the three high-speed railway long tunnels was 83.4%, and that of the two urban railway long tunnels was 85.5%, indicating that the deviation between them was small. The mean normal operation rate of the monitoring hardware in the long tunnels of the five high-speed and urban railway lines was 84.2%.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.1
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• pp.3-8
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• 2006

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module optimal design technique and horizontal split of die insert were investigated for determining appropriate dimensions of components of multi-former die set. Results obtained, using the modules, enable the design and manufacture of a die set for a multi-former to be more efficiently performed.