• Journal of the Korean Institute of Navigation
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• v.22 no.4
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• pp.15-19
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• 1998

This paper concerns a bulk or semibulk cargo ship scheduling problem with a single loading port. This type of ship scheduling problem is frequently needed in real world for carrying minerals or agricultural produce from a major single production zone to many destinations scattered over a large area of the world. The first optimization model for this problem was introduced by Ronen (1986) as a nonlinear mixed integer program. The model developed in this paper is an improvement of his model in the sense that nonlinearities and numerous unnecessary integer variables have been eliminated. By this improvement we could expect real world instances of moderate sizes to be solved optimal solutions by commercial integer programming software. Similarity between the ship scheduling model and the capacitated facility location model is also discussed.

• Journal of Chest Surgery
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• v.55 no.2
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• pp.168-170
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• 2022

A 58-year-old female patient was diagnosed with hypopharyngeal cancer with extension to the invasion of the upper esophagus. After 2 cycles of durvalumab as neoadjuvant therapy, total laryngo-esophagectomy using a single-port (SP) system via a subcostal incision was done. The operation was completed within 41 minutes, and the patient recovered without esophagectomy-related complications. The patient received total laryngectomy and esophagectomy using a robotic SP system via a 3-cm-long subcostal incision and gastric pull-up under laparotomy. During the postoperative period, the patient suffered from anastomotic leakage, but recovered with vacuum therapy. Here, we report the first successful human case of esophagectomy using an SP system.

• Journal of Gastric Cancer
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• v.15 no.2
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• pp.132-138
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• 2015

Single-incision laparoscopic total gastrectomy for gastric cancer has recently been reported by Seoul National University Bundang Hospital. However, this is not a popular procedure primarily because of the technical difficulties involved in achieving consistent intracorporeal esophagojejunostomy. At Seoul National University Bundang Hospital, we recently introduced a simple, easy-to-use, low-profile laparoscopic manual scope holder that enables the maintenance of a stable field of view, the most demanding condition in single-port gastrectomy. In this technical report, we describe in detail the world's first solo single-incision laparoscopic total gastrectomy with D1+ lymph node dissection and intracorporeal esophagojejunostomy for proximal early gastric cancer.

• Journal of electromagnetic engineering and science
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• v.17 no.2
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• pp.65-70
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• 2017

The design and implementation aspects of a new single-balanced mixer for ultra-wideband (UWB) applications are presented in this study. The proposed mixer utilizes a miniaturized UWB ring coupler as a balun, consisting of a pair of in-phase and inverted-phase transitional structures. The well-balanced UWB performance of the ring coupler, aside from the optimized diode matching, results in improved conversion loss and inter-port isolations for a wide bandwidth. The size of the implemented single-balanced diode mixer is reduced to about 60% of the area of the conventional single-balanced ring diode mixer. The measured results of the proposed mixer exhibit an average conversion loss of 7.5 dB (minimum 6.7 dB) and a port-to-port isolation of greater than 18 dB over a UWB frequency range of 3.1-10.6 GHz. The measured results agree well with the simulated results.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.486-487
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• 2012

In this paper, novel three-port active power decoupling (APD) method for applying 250[W] micro-inverter. This type using third port for active power decoupling stores the surplus energy and supplies sufficient energy to grid. Conventional decoupling circuit is applied in single phase grid connected micro-inverter especially single-stage configuration like flyback-type DC-AC inverter. In this passive power decoupling method, electrolytic capacitor with large capacitance is needed for decoupling from constant DC power and instantaneous AC power. However the decoupling capacitor is replaced with film capacitor by using APD, thus the overall system can achieve smaller size and long lifespan. Proposed three-port flyback inverter is verified by design and simulation.

• Journal of Korean Port Research
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• v.14 no.3
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• pp.361-371
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• 2000

A demand of marine outfall system has been much increased for the effective disposal of the wastewater due to population and industrial development at the coastal areas. The outfall system discharges primary or secondary treated effluent into the coastline, or at the deep water, or between these two. The discharge is carried out by constructing a pipeline on the sea bed with a diffuser or with a tunnel, risers and appropriate. The effluent, which has a density similar to that of fresh water, rises to the sea surface forming plume or jet, together with entraining the surrounding salt water and becomes very dilute. Thus there have been growing interests about plume behaviour around the outfall system. Plume or jet discharged from single-port or multi-port diffuser might cause certain impacts on coastal environment. Near field mixing characteristics of discharged water field using CORMIX model have been studied for effective outfall design various conditions on ambient current, depth, flow rate, effluent concentration, diffuser specification, port specification etc.. This kind of analysis is necessary to deal with water quality problems caused by the ocean discharge. The analyzed result was applied to the Pusan Jungang effluent outfall system plan.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.281-292
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• 2008

Prefabricated Board Drains (PBDs) recently become more widely used than conventional sand drains in improving soft ground because the PBD is more time and cost effective. The performance of PBDs is affected by disturbance in the adjacent soil formation during inserting mandrels, the intrusion of fine particles into filter fabric, and necking of the drain by excessive lateral pressure especially occurring in very deep clay formation such as the Busan New Port site. In this study, the PBD with double-core is introduced, which seems to overcome the shortcomings of usual single-core PBDs. An in-situ test program was established in the Busan New Port site, in which a set of the double-core PBDs and the single-core PBDs was installed to compare the efficiency of each of the drains. The discharge capacity of the double-core and the single-core PBDs was compared for various confining pressures in the modified Delft test and the chamber test. A series of CRS consolidation tests was performed in order to obtain profiles of void ratio-effective stress and void ratio-permeability relationships in the Busan New Port site that are used as input date in performing a numerical program ILLICON. The numerically simulated settlements of ground surface in the test site are in good agreement with those of in-situ measurements. In addition, the performance of the double-core and single-core PBDs has been experimentally and numerically compared in this paper.

• Advances in pediatric surgery
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• v.20 no.2
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• pp.48-52
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• 2014

Purpose: Currently the substantial clinical benefits of single-port laparoscopic appendectomy (SLA) over conventional three-port laparoscopic appendectomy (CLA) are equivocal. The aim of this study was to compare surgical outcomes between SLA and CLA in children with acute appendicitis. Methods: A single blind prospective randomized single center study was performed to compare the surgical outcomes of SLA and CLA. A total of 105 patients were randomized and various parameters were analyzed, 52 patients with SLA and 53 patients with CLA between July 2013 and March 2014. Patients with sonographically confirmed acute appendicitis were randomly assigned to receive either SLA or CLA. The outcome measurements were operating time, wound complication, and intraperitoneal morbidities, postoperative pain score and cosmetic result score. Results: Operating time is significantly longer in SLA ($70.4{\pm}26.7$ minutes vs. $58.0{\pm}23.4$ minutes; p=0.016). There were no significant differences in the postoperative wound complication rate and intraperitoneal morbidities between two groups. There were no significant differences in postoperative resting pain score ($6.6{\pm}2.5$ vs. $6.3{\pm}2.5$; p=0.317) and activity pain score ($6.9{\pm}2.4$ vs. $6.3{\pm}2.5$; p=0.189), and the cosmetic result score ($9.2{\pm}1.1$ vs. $9.1{\pm}1.4$; p=0.853). Conclusion: Although SLA would be a safe and feasible procedure in children, SLA could not demonstrate the clear benefit over CLA.

• International Commerce and Information Review
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• v.13 no.2
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• pp.27-48
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• 2011

Single window has become a critical point of trade facilitation. While Korea has set up the first web based single window 'uTtradeHub', China has also been working on a seamless single window. As strong governmental support, advanced technology, leading agency and legal framework are success factors for single window, China already has solid foundation for this. For the leading agency, this research suggests the CIECC as a leading agency with linkage to E-Port service for seamless trade service for companies. We expect that Chinese single window will materialize in near future by a leading agency with the help of strong governmental support.

• Journal of Gastric Cancer
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• v.21 no.2
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• pp.132-141
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• 2021

Purpose: Intracorporeal esophagojejunostomy during reduced-port gastrectomy for proximal gastric cancer is a technically challenging technique. No study has yet reported a robotic technique for anastomosis. Therefore, to address this gap, we describe our reduced-port technique and the short-term outcomes of intracorporeal esophagojejunostomy. Materials and Methods: We conducted a retrospective review of patients who underwent a totally robotic reduced-port total or proximal gastrectomy between August 2016 and March 2020. We used an infra-umbilical Single-Site^® port with two additional ports on both sides of the abdomen. To transect the esophagus, a 45-mm endolinear stapler was inserted via the right abdominal port. The common channel of the esophagojejunostomy was created between the apertures in the esophagus and proximal jejunum using a 45-mm linear stapler. The entry hole was closed with a 45-mm linear stapler or robot-sewn continuous suture. All anastomoses were performed without the aid of an assistant or placement of stay sutures. Results: Among the 40 patients, there were no conversions to open, laparoscopic, or conventional 5-port robotic surgery. The median operation time and blood loss were 254 min and 50 mL, respectively. The median number of retrieved lymph nodes was 40.5. The median time to first flatus, soft diet intake, and length of hospital stay were 3, 5, and 7 days, respectively. Three (7.5%) major complications, including two anastomosis-related complications and a case of small bowel obstruction, were treated with an endoscopic procedure and re-operation, respectively. No mortality occurred during the study period. Conclusions: Intracorporeal esophagojejunostomy during reduced-port gastrectomy can be safely performed and is feasible with acceptable surgical outcomes.