• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.649-659
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• 2016

This paper describes control algorithm and control structure of vehicle control unit for range-extended electric vehicle equipped with engine-generator system, and specially presents methods which determine optimal operating points and decreases a vibration or a shock for operating the engine-generating system. The vehicle control algorithm is consisted of several parts which are sequence control, calculation of wheel demand torque, determination of operating points, and management of operating points and so vehicle controller has be made possible to efficiently manage calibration parameters. The control algorithm is evaluated by driving test modes, launching performance and operating engine-generator system and so on. In conclusion, this paper present methods for extending a mileage, improving a launching performance and reducing vibration or shock when the engine-generating system is starting or is stopping.

• Journal of the Korea Safety Management & Science
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• v.2 no.4
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• pp.1-8
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• 2000

Equipment and machine of industrial plant are give effect to mechanical-stress of many working-stop or long time operating. Therefore, to be old and decrepit of every king of equipment. As long time operating equipment period into increase conservation and of repair equipment time is efficacious necessity of utility factor gradually that of productivity of diminution and complete equipment expense of increase. Conservation at special skill working and necessity is that will effectually and complete a period prevention management diagnosis can conservation point at issues at in advance.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.391-393
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• 2008

This paper is analysed by switching overvoltage on operating reclosing in 154 [kV] combined transmission systems. Combined transmission systems are modeled by EMTP/ATPDraw program. It is fault condition that simulate high resistance earth fault. The simulation is carried out considering variation of parameters such as resistance value of fault point and rate of underground line.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.510-514
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• 1989

This paper presents a new converter composed of a P.W.M controller and a resonant converter which operates at a constant frequency. This converter has relatively simple control circuits and high conversion efficiency. The optimum operating point corresponding to maximum efficient for the S.R.C and P.R.C operating above resonance is obtained.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.597-602
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• 1987

This paper proposes a voltage-fed high frequency resonant inverter having variable voltage variable frequency(VVVF) control function. VVVF control is performed by PWM-TRC method in the boost type chopper and PFM-TRC method in the high frequency resonant inverter. This circuit is suitable for induction heating and melting power supply in industry. The operating characteristics of this inverter are discussed from a theoretical point of view. The results of operating characteristic analyses are given leading to complete designing data.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.317-319
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• 2019

In this paper, a three level duty cycle controlled half bridge LLC converter for EV charger application is presented. The topology and operating regions of the converter are discussed. The equations of the converter are derived in time domain. A small signal model of the converter is developed by perturbation and linearization of the steady state model about their operating point using Extended Describing function.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.2
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• pp.257-269
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• 2014

The purpose of this study was to investigate the change of perceptions of students', parents', teachers' on creativity and character education at the model school for creativity and character education. This study used pre and post tests to examine the effects of creativity and character education on students, parents, and teachers. The results were as follows. Firstly, operating model school for creativity and character education brought about the statistically meaningful changes of students' perception on creativity and character education. However, the changes seemed that the level of their perception on creativity and character education was not rational as the average is about 3.5 point. Secondly, operating model school for creativity and character education brought about the statistically meaningful changes of parents' perception on creativity and character education. However, the changes seemed that the level of their perception on creativity and character education was not rational as the average was about 3.5 point like their children. thirdly, operating model school for creativity and character education brought about the statistically meaningful changes of teachers' perception on creativity and character education. The changes seemed that the level of their perception on creativity and character education was rational as the average was about 4.5 point unlike their students and school parents. Fourthly, it seemed that the perception on creativity and character education showed a difference among students, school parents, and teachers.

• Journal of Minimally Invasive Surgery
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• v.21 no.4
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• pp.154-159
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• 2018

Purpose: Intussusception is a common cause of intestinal obstruction in children. While most patients can be treated by enema reduction, about 20% require surgery. We investigated the usefulness and feasibility of laparoscopic surgery and the intraoperative risk of bowel resection. Methods: We retrospectively reviewed pediatric patients who underwent surgery for intussusception from 2010 to 2017. We collected data for age, gender, body weight, associated symptoms, duration of symptoms, white blood cell count, operating time, and postoperative complications. Results: Of 155 patients, 37 (23.8%) underwent surgery due to enema reduction failure in 29 (78.3%), recurrence in 6 (16.3%), a suspicious lead point in 1, and suspicious ischemic change observed on ultrasonography in 1. The mean age was $26.8{\pm}18.9$ months (range, 3.5~76.7 months), and the mean body weight was $12.9{\pm}3.9kg$ (range, 5.4~22.2 kg). Laparoscopic surgery was successful in 29 patients (78.4%), and 7 (18.9%) needed bowel resection and anastomosis. The mean operating time was $56.7{\pm}32.8min$. A lead point was found in 3 patients in the bowel resection group (p=0.005); in addition, the operating time and hospital stay were longer in this group. There were no intra- or postoperative complications. Conclusion: Laparoscopic surgery was successful in 78.4% of the patients with a short hospital stay and early oral intake. The only predictive factor for bowel resection was the presence of a lead point. Laparoscopic surgery may be an optimal treatment intervention for children with intussusception, except for those who show initial peritonitis.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.1
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• pp.44-54
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• 2023

In this study, the second-order Nomoto's nonlinear expansion model was implemented as a Tagaki-Sugeno fuzzy model based on the heading angular velocity to design the automatic steering system of a ship considering nonlinear elements. A Tagaki-Sugeno fuzzy PID controller was designed using the applied fuzzy membership functions from the Tagaki-Sugeno fuzzy model. The linear models and fuzzy membership functions of each operating point of a given nonlinear expansion model were simultaneously tuned using a genetic algorithm. It was confirmed that the implemented Tagaki-Sugeno fuzzy model could accurately describe the given nonlinear expansion model through the Zig-Zag experiment. The optimal parameters of the sub-PID controller for each operating point of the Tagaki-Sugeno fuzzy model were searched using a genetic algorithm. The evaluation function for searching the optimal parameters considered the route extension due to course deviation and the resistance component of the ship by steering. By adding a penalty function to the evaluation function, the performance of the automatic steering system of the ship could be evaluated to track the set course without overshooting when changing the course. It was confirmed that the sub-PID controller for each operating point followed the set course to minimize the evaluation function without overshoot when changing the course. The outputs of the tuned sub-PID controllers were combined in a weighted average method using the membership functions of the Tagaki-Sugeno fuzzy model. The proposed Tagaki-Sugeno fuzzy PID controller was applied to the second-order Nomoto's nonlinear expansion model. As a result of examining the transient response characteristics for the set course change, it was confirmed that the set course tracking was satisfactorily performed.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.73-74
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• 2011

Phase-shedding, one famous technology for multi-phase converters, is implemented in a bi-directional multi-phase converter for ESS. It reduces active operating modules at light load to compensate efficiency. Shedding point, the load level where the converter changes the number of active modules, is important factor that affects the effect of phase-shedding. Loss analysis is done for determining shedding point. Phase-shedding hysteresis is applied so that excessive phase transition is avoided. This paper proposes shedding point correction where the shedding point is adaptively corrected by calculating a new shedding point.