• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.215-220
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• 2021

As the role of robots expands, flexible task planning methods are attracting attention from various domains. Many task planning frameworks are introduced to efficiently work in a wide range of areas. In order to work well in a broad region with multiple robots, various communication conditions should be controlled by task planning frameworks. However, few methods are proposed. In this paper, we propose mission planning methods according to the communication status of robots. The proposed method was verified through experiments assuming different communication states with a multi-robot system.

• Journal of Digestive Cancer Research
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• v.5 no.1
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• pp.44-49
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• 2017

Background: Recently, endoscopic submucosal dissection (ESD) with laparoscopic sentinel lymph node dissection, named ESN or endoscopic full-thickness gastric resection with laparoscopic sentinel lymph node dissection, named Hybrid-natural orifice transluminal endoscopic surgery (NOTES) was suggested the possibility of minimally invasive treatment for patients with early gastric cancer (EGC) who were beyond the indication of ESD. This study aimed to evaluate the outcomes of ESN or Hybrid-NOTES. Methods: We retrospectively analyzed patients treated with these therapies from January 2009 to May 2013 in terms of short- and long-term outcomes. Each patient was diagnosed with EGC but was not included in ESD indications and had the high risk of lymph node metastasis (LNM). Results: A total of 42 patients with EGC treated by ESN or Hybrid-NOTES. Of the 21 patients who underwent ESN, a total of 4 patients underwent additional gastrectomy, 1 with LNM, 1 with surgical complication, and 2 with noncurative resection. Of the 21 patients who underwent Hybrid-NOTES, a total of 5 patients underwent additional surgery, 1 with LNM, 2 with surgical complication, and 2 with noncurative resection. Overall survival was 100% over a mean follow-up of 75 months, but 3 patients underwent ESD or gastrectomy with metachronous lesion. And 1 patient who had received ESN was found to have a metastatic lymph node and undergo palliative chemotherapy. Conclusion: ESN or Hybrid-NOTES showed favorable short-and long-term outcomes. These methods may be utilized as a bridge between ESD and gastrectomy in the case of EGC which is more likely to have LNM beyond the ESD indications.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.3
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• pp.99-106
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• 1995

PWM(Pluse Width Modulation) induction motor drives are being used in greater numvers through a wide variety of industrial and commercial applications. In this paper, a new speed control algorithm (hybrid algorithm) for induction motor drives that uses regular sampled PWM and harmonic elimination PWM is presented. The hybrid algorithm in implemeted on the computer to obtain solutions from the calculation equations of the width of the pulses and the firing angles for the selected harmonic elimination. this paper describes the time delay effects and the suitable compensating methods moreover, optical transmission system for driving signals is proposed and is compared with general trnasmission system. The hybrid inverter was tested with induction motor, and these test results are shown that this hybrid inverter closely approximates and exhibits many of the desirable performance characteristic distortions and eliminated the objectionable harmonics. Finally, detailed experimental investigation of the proposed hybrid scheme in presented.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.245-248
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• 2006

Hybrid propulsion systems provide many advantages in terms of stable operation and safety. However, classical hybrid rocket motors have lower fuel regression rate and combustion efficiency compared to solid propellant rocket motor. Accordingly, the recent research efforts are focused on the improvement of engine efficiency and regression rate in the hybrid rocket engine. The present study has numerically investigated the combustion processes in the hybrid rocket engine. The turbulent combustion is represented by the flamelet model and Low Reynolds number $k-{\varepsilon}$ turbulent model is employed to reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect. Based on numerical results, the detailed discussions have been made for the effects of oxygen injection methods and oxygen injection flow rate on flame structure and regression rate in the vortex hybrid rocket engines

• Near Infrared Analysis
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• v.1 no.2
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• pp.1-8
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• 2000

Using the net analyte signal, hybrid linear analysis was proposed to predict chemical concentration. In this paper, we select a sample from training set and apply orthogonal signal correction to obtain an improved pseudo unit spectrum for hybrid least analysis. using the mean spectrum of a calibration training set, we first show the calibration by hybrid least analysis is effective to the prediction of not only chemical concentrations but also physical property variables. Then, a pseudo unit spectrum from a training set is also tested with and without orthogonal signal correction. We use two data sets, one including five chemical concentrations and the other including ten physical property variables, to compare the performance of partial least squares and modified hybrid least analysis calibration methods. The results show that the hybrid least analysis with a selected training spectrum instead of well-measured pure spectrum still gives good performances, which is a little better than partial least squares.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.524-527
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• 2004

Hybrid rocket had many advantage with compared to solid and liquid rockets. However, the engines have not yet been used in practical rocket systems, due mainly to the disadvantage of hybrid combustion, such as low fuel regression rate. In this study, lab-scale hybrid motor was designed and manufactured. And the methods of regression rate improvement were considered. Test firings with thrusts up to 300 N were conducted with GOX and transparent PMMA. Thrust was calculated with the pressure of the combustion chamber and the regression rate was measured in with variation of oxidizer flow rate. The regression rates showed a strong dependency on GOX mass flux. The frequency analysis technique of the bulk-mode oscillation of motor was applied to a hybrid rocket motor and was based on the principle that this frequency was inversely proportional to the square root of the chamber volume. Several problems and solutions of operating hybrid rocket were presented.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.351-352
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• 2023

In order to respond to changes in the industrial environment such as the 4th industrial revolution, university education also needs active educational innovation efforts. This study proposed a construction construction hybrid curriculum that can actively utilize online education in the direction of educational innovation in domestic universities. The hybrid curriculum was based on online learning through lecture videos used in team-based learning. The hybrid curriculum additionally allows learners to choose their learning methods. In a hybrid class, learners can choose the class participation method they want from offline classroom or online real-time. Hybrid classes are considered to strengthen learners' options and take a step forward in learner-centered education.

• Journal of the Korean Data and Information Science Society
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• v.17 no.2
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• pp.269-278
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• 2006

This paper presents the new hybrid data mining technique using error pattern, modeling of improving classification accuracy. The proposed method improves classification accuracy by combining two different supervised learning methods. The main algorithm generates error pattern modeling between the two supervised learning methods(ex: Neural Networks, Decision Tree, Logistic Regression and so on.) The Proposed modeling method has been applied to the simulation of 10,000 data sets generated by Normal and exponential random distribution. The simulation results show that the performance of proposed method is superior to the existing methods like Logistic regression and Discriminant analysis.

• Structural Engineering and Mechanics
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• v.46 no.3
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• pp.403-416
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• 2013

This paper describes new optimization strategy that offers significant improvements in performance over existing methods for geometry design of frame structures. In this study, an imperialist competitive algorithm (ICA) and ant colony optimization (ACO) are combined to reach to an efficient algorithm, called Imperialist Competitive Ant Colony Optimization (ICACO). The ICACO applies the ICA for global optimization and the ACO for local search. The results of optimal geometry for three benchmark examples of frame structures, demonstrate the effectiveness and robustness of the new method presented in this work. The results indicate that the new technique has a powerful search strategies due to the modifications made in search module of ICACO. Higher rate of convergence is the superiority of the presented algorithm in comparison with the conventional mathematical methods and non hybrid heuristic methods such as ICA and particle swarm optimization (PSO).

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1431-1433
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• 1987

To transmit the image data at low rate, motion compensated(MC) hybrid coding scheme is used generally. In this scheme since coder performance could be decreased when scene change happens, another prediction method must be employed. In this paper we present two prediction methods. One is using the mean of neighboring block which was already transmitted. The others is estimating the current block with the neighboring blocks. When the proposed methods are applied to the conventional Me hybrid coding scheme, it is found that SNR gain of 7 dB is achieved and bit rate can be also reduced above 30%.