• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.341-341
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• 2000

This paper presents a sliding mode control(SMC) design method for single input linear systems with uncertainties and time delay in the state. We define a sliding surface for the augmented system with a virtual state which is defined from the nominal system. We make a virtual state from optimal control input using LOR(Linear Quadratic Regulator) and the states of the nominal system. We construct a controller that combines SMC with optimal controller. The proposed sliding mode controller stabilizes on the overall closed-loop system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.11a
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• pp.111-114
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• 1997

동영상 압축 알고리즘에서 움직임 추정기법은 매우 중요한 역할을 담당하는 반면, 수행시간이나 하드웨어 구현에 어려움이 많아 이를 개선하기 위한 알고리즘들이 개발되어 왔다. 본 논문에서는 적절한 화소 분류를 통해 우수한 화질과 적은 계산량, 간단한 하드웨어 구조를 가지는 새로운 움직임 추정기법을 제안한다. 기존의 1-비트 화소 분류 방법에서 변형된 새로운 비용 함수를 이용한 2-비트, 3-비트 화소 분류 방법과 2차 비용함수를 이용한 화소 분류 방법을 제안한다. 또한 여러 고속 움직임 추정 알고리즘과도 쉽게 연결하여 사용할 수 있으며 우수한 성능을 나타내는 것을 모의 실험을 통해 보였다.

• The Science & Technology
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• no.1 s.428
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• pp.87-92
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• 2005

1905년은 아인슈타인의 일생 가운데 가장 생산적인 해였다. 그는 그 해에 특수 상대론, 광전효과, 브라운 운동 및 E=mc² 등 네편의 주옥같은 논문을 발표했다. 한국물리학회와 과학문화진흥회는 이를 기념하기 위하여 2005년 7월 1일부터 2006년 2월말 까지 창경원 옆에 있는 서울 과학관에서 아인슈타인 100주년 기념 전시회를 갖는다. 전시회는 1)아인슈타인의 생애 2)시간과 공간 3)빛, 파동 및 물질 4)아인슈타인의 우주 5)아인슈타인과 예술 등 다섯 가지 주제를 체험위주로 기획하고 있다. 관람객들이 특수 상대론을 설명이 아니라 체험함으로써 일상생활에서는 어떻게 이용되고 있는가를 알도록 전시장을 꾸미고 있다. 각 주제별로 그 내용을 스케치해본다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.103-108
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• 2020

Generally, the cargo tank of LPG carriers corresponds to an independent tank Type A defined by the International Maritime Organization (IMO). The outside of the tank is insulated by polyurethane foam, and the tank is made of expensive low temperature steel that can withstand temperatures as low as -50℃. The cargo tank is composed of outer shell plates, bulkheads, stiffeners, web frames, and stringers. Among them, the outer shell plates, bulkheads, and stiffeners can be designed without structural analysis by the Classification Rules and are constructed easily through optimal design. On the other hand, optimal design, including numerous structural analysis, is not performed because web frames and stringers should be designed and approved through structural analysis. Only adequate design, which determines the design dimensions through several dozen structural analysis, is performed. In this study, for finite element analysis, eight loading conditions were applied, and the deformation of the entire ship for each loading condition was considered. The minimum weight design was performed for the web frames of cargo tanks in the 82,000 ㎥ LNG carrier through the gradient-based optimization technique, and the weight was reduced by approximately 108 tons per ship.

• Journal of the Korea Society of Computer and Information
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• v.18 no.3
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• pp.119-126
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• 2013

In this paper, we propose and describe the system to visualize the story of contents such as movies and novels. Character-net is applied as story model in order to visualize story. However, it is the form to be accumulated for total movie story, though it can depict the relationship between characters. We have developed the system that analyzes and shows the variation of Character-net and characters' tendency in order to represent story variation depending on movie progression. This system is composed by two windows that can play and analyze sequential Character-nets by time, and can analyze time variant graph of characters' degree centrality. First window has a function that supports to find important story points like the scenes that main characters appear or meet firstly. Second window supports a function that track each character's tendency or a variation of his tendency through analyzing in-degree graph and out-degree. This paper describes the proposed system and discusses additional requirements.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.1
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• pp.46-56
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• 2008

Double Patching is a multicasting technique for a VoD system which has been proposed to provide a true VoD service by making clients share a long patching stream as well as a regular stream For subsequent short patching streams, the technique always makes the long patching stream have extra data that will be played back during a double period of a patching window. In this paper, we propose a technique, using the start time of the latest short patching stream, optimizes Double Patching by deleting the useless data included in the long patching stream when the patching window of the long patching stream closes. The mean requirement for the server's bandwidth to provide the true VoD service is used as a performance metric, and the effect of the request inter-arrival time, the size of the client's local buffer and the video length on the mean bandwidth requirement is evaluated. Performance evaluation result shows that the proposed technique optimizes Double Patching in all cases.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.527-535
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• 2021

The STEAM education was applied to science high school students, and changes in perceptions of students and teachers were investigated after class treatment. By the results of the student's perception survey, very positive results were found in increasing problem-solving capabilities, educational satisfaction, etc. More than 98% of students said they would continue to participate in STEAM education classes. Meanwhile, the lack of time for class activities put a burden on students to complete the problems during class. Especially nanoscience content and activities were properly organized in consideration of the level of cognitive development of the students. In addition, as a result of a survey of teachers' perceptions for students, more than 80.0% of teachers responded very positively in 'self-directed learning ability' and 'problem-solving capability', etc.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.1-11
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• 2023

The purpose of this study is to develop a discussion-centered teaching and learning model for nurturing creative and convergence talents. Regarding the research method, a draft model on discussion-centered teaching and learning was devised, and the model was completed through expert validation. The final draft was revised and supplemented by verifying how valid the model was when applied in class by using the derived final draft. Compared with the draft on discussion-centered teaching and learning model, the final model focused on text-reading emphasis, methods of questioning, and question generation strategies, excluding jigsaw discussions. The discussion-centered teaching and learning model developed in this study is expected to help instructors foster creative and convergence talents. Three suggestions have been provided to effectively apply this model to the field. First, an attitude of listening and respect is required during a discussion. Second, a plan should be considered on how to induce active participation of learners participating in the discussion. Third, the importance of managing discussion time was emphasized.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.4
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• pp.1-6
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• 2003

In this Paper, the moving image is detected by a collision preventive system. The noise of these images is reduced by a mean filter. In case of detecting a movement with a binary difference image the moving area is detected exactly by the labeling and the projective method. When the image move slowly with the tracking mode of the system, the center of the tracking window move to the previous tracking window. And the tracking windows are divided into a tracking mode and a coasting mode which are determine by the Contrast-Difference Correlation of the date obtained from a difference image. The coasting mode determine whether continue the tracking step or not comparing the coasting-time values to reducing the error by the disturbance. The coasting and tracking of these moving images are verified by the result of the simulation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.6
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• pp.568-576
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• 2010

It is widely known that the leak locating of underground plastic pipelines is much more difficult than that of cast iron pipelines. The precision of the leak locating depends upon the speed of leak signal and the time delay estimation between the two sensors on the pipeline. In this paper, six different windowing filters are considered to improve the time delay estimation especially for the plastic pipelines. The time delay is usually estimated from the peak time of cross-correlation functions. The filtering windows including rectangle, Roth, Wiener, SCOT, PHAT and maximum likelihood are applied to derive the generalized cross-correlation function and compared each other. Experimental results for the actual plastic underground water supply pipeline show that the introduction of the filtering windows improved the precision of time delay estimation. Some window functions provide excellent leak locating capability for the plastic pipe of 98 m long, which is less than 1 % of the pipe lengths. Also a new probabilistic approach that the combinations of all results from each filtering window is suggested for the better leak locating.