• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.230.2-230.2
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• 2010

천연가스 수증기 개질 반응에 사용되는 펠릿 촉매의 단점인 열 및 물질 전달 제한, 낮은 effectiveness factor, 압력강화와 channeling 등의 문제점을 해결 하고자 모노리스 형태의 금속 구조체 촉매를 본 연구에 적용 하였다. Fecralloy 재질의 금속 구조체에 Ni 촉매를 워시코팅 (wash coating) 하여 제조 하였으며, 이를 천연가스 수증기 개질 반응에 적용하여 수소를 생산하였다. 실험 조건으로는 S/C ratio를 3으로 고정하여 온도를 $600^{\circ}C{\sim}800^{\circ}C$로 변화 시켰으며, GHSV $3000{\sim}30000h^{-1}$에서 진행 되었다. 구조체 촉매 코팅에 사용된 Ni 촉매의 BET, TPR, H2-chemisorption, SEM, EDS의 특성분석을 수행 하였다. 온도별 테스트에서 모노리스 형태의 금속 구조체 촉매가 펠릿 형태의 촉매에 비해 우수한 열전달 효과로 인해 낮은 퍼니스 온도와 높은 반응 활성을 나타내었으며, GHSV 변화에 따른 성능평가 결과도 15wt% $Ni/MgAl_2O_4$펠릿 촉매와 비교하여 금속 구조체 촉매가 높은 활성을 보였다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.224.1-224.1
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• 2010

본 연구에서는 천연가스 수증기 개질반응에 니켈 촉매가 코팅된 금속 구조체 촉매를 적용하여 수소를 생산하였다. 금속구조체 촉매는 기존 펠릿 촉매가 충진 된 촉매반응기에 비해 열 및 물질 전달 특성이 우수하여 이를 여러 개질반응에 적용하고자하는 연구가 수행되어 왔다. 하지만, 기존 금속구조체 촉매의 개발에 있어 촉매와 금속 지지체간의 안정한 결합을 통한 열안정성 확보에 대한 문제는 여전히 해결과제로 남아 있다. 따라서, 본 연구에서는 니켈 촉매를 금속 지지체에 안정하게 부착하기 위한 금속 지지체 표면 처리 방법을 개발하였으며 금속 구조체의 형상에 상관없이 균일한 표면처리가 가능하였다. 개발된 표면 처리방법을 적용한 금속 구조체 촉매는 촉매와 금속지지체간의 결합력 향상으로 인해 120시간 이상 안정한 반응활성을 보였다. 또한, 빠른 공간속도에서도 펠릿촉매와 표면처리를 적용하지 않은 금속 구조체 촉매에 비해 높은 촉매 활성을 보였다. 뿐만 아니라, 본 연구에서 개발된 표면처리를 모노리스와 폼을 비롯한 다양한 형상의 금속구조체 촉매에 적용하여 기하학적 표면 특성에 따른 촉매의 활성 차이를 살펴보았다. 겉보기 표면적이 넓은 금속구조체일 수록 촉매의 고분산 코팅에 유리하여 높은 활성을 보였다.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1953-1957
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• 2004

The machine vision has been applied to a number of industrial applications for quality control and automations to improve the manufacturing processes. In this paper, the automation system using the machine vision is developed, which is applicable to the marking process in a steel production process line. The working environment is very harsh to workers so that the automatic system in the steel industry is required increasingly. The developed automatic marking system consists of several mechanical and electrical elements such as the laser position detecting sensor system for a structured laser beam which is projected to the billet in order to detect the geometry of the billet. An image processing algorithm has been developed to percept the two center positions of a camera and a billet, respectively, and to align two centers. A series of experiments has been conducted to investigate the performance of the proposed algorithm. The results show that two centers of the camera and the billet could be detected very well and differences between two center positions could be also decreased via the proposed tracking algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.10
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• pp.1005-1013
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• 2008

This paper describes a new sensor system for 3D range measurement using the structured infrared light. Environment and obstacle sensing is the key issue for mobile robot localization and navigation. Laser scanners and infrared scanners cover $180^{\circ}$ and are accurate but too expensive. Those sensors use rotating light beams so that the range measurements are constrained on a plane. 3D measurements are much more useful in many ways for obstacle detection, map building and localization. Stereo vision is very common way of getting the depth information of 3D environment. However, it requires that the correspondence should be clearly identified and it also heavily depends on the light condition of the environment. Instead of using stereo camera, monocular camera and the projected infrared light are used in order to reduce the effects of the ambient light while getting 3D depth map. Modeling of the projected light pattern enabled precise estimation of the range. Identification of the cells from the pattern is the key issue in the proposed method. Several methods of correctly identifying the cells are discussed and verified with experiments.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.15 no.4
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• pp.232-239
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• 2015

Studies on the control of the inverted pendulum type system have been widely reported. This is because it is a typical complex nonlinear system and may be a good model for verifying the performance of a proposed control system. In this paper, we propose the design of some fuzzy logic control (FLC) systems for controlling a Segway-type mobile robot, which is an inverted pendulum type system. We first derive a dynamic model of the Segway-type mobile robot and then analyze it in detail. Next, we propose the design of some FLC systems that have good performance for the control of any nonlinear system. Then, we design two conventional FLC systems for the position and balance control of the Segway-type mobile robot, and we demonstrate their usefulness through simulations. Next, we point out the possibility of simplifying the design process and reducing the computational complexity,, which results from the skew symmetric property of the fuzzy control rule tables. Finally, we design two other FLC systems for position and balance control of the Segway-type mobile robot. These systems have only one input variable in the FLC systems. Furthermore, we observe that they offer similar control performance to that of the conventional two-input FLC systems.

• Journal of Korea Multimedia Society
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• v.21 no.2
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• pp.199-209
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• 2018

Recently, services provided to consumers are increasingly being combined with big data such as low-priced shopping, customized advertisement, and product recommendation. With the increasing importance of big data, the web crawler that collects data from the web has also become important. However, there are two problems with existing web crawlers. First, if the URL is hidden from the link, it can not be accessed by the URL. The second is the inefficiency of fetching more data than the user wants. Therefore, in this paper, through the Casper.js which can control the DOM in the headless brwoser, DOM event is generated by accessing the URL to the hidden link. We also propose an intelligent web crawler system that allows users to make steps to fine-tune both Structured and unstructured data to bring only the data they want. Finally, we show the superiority of the proposed crawler system through the performance evaluation results of the existing web crawler and the proposed web crawler.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.100-104
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• 1993

In Part 1, we derived robust stability conditions for an LTI interconnected to time-varying nonlinear perturbations belonging to several classes of nonlinearities. These conditions were presented in terms of positive definite solutions to LMI. In this paper we address a problem of synthesizing feedback controllers for linear time-invariant systems under structured time-varying uncertainties, combined with a worst-case H$_{2}$ performance. This problem is introduced in [7, 8, 15, 35] in case of time-invariant uncertainties, where the necessary conditions involve highly coupled linear and nonlinear matrix equations. Such coupled equations are in general difficult to solve. A convex optimization approach will be employed in this synthesis problem in order to avoid solving highly coupled nonlinear matrix equations that commonly arises in multiobjective synthesis problem. Using LMI formulation, this convex optimization problem can in turn be cast as generalized eigenvalue minimization problem, where an attractive algorithm based on the method of centers has been recently introduced to find its solution [30, 361. In the present paper we will restrict our discussion to state feedback case with Popov multipliers. A more general case of output feedback and other types of multipliers will be addressed in a future paper.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.2
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• pp.109-114
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• 2002

Various inverted pendulum systems have been frequently used as a model for the performance test of the proposed control system. We first identify a rotary-type inverted pendulum system by the Euler-Lagrange method and then design a FLC (Fuzzy Logic Controller) fur the plant. FLC`s are one of useful control schemes fur plants having difficulties in deriving mathematical models or having performance limitations with conventional linear control schemes. Many FLC`s imitate the concept of conventional PD (Proportional-Derivative) or PI (Proportional-Integral) controller. That is, the error e and the change-of-error are used as antecedent variables and the control input u the change of control input Au is used as its consequent variable for FLC`s. In this paper we design a simple-structured FLC for the rotary inverted pendulum system. We also perform some computer simulations to examine the tracking performance of the closed-loop system.

• Journal of The Korean Association For Science Education
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• v.33 no.3
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• pp.569-580
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• 2013

This study examined how a Structured Reading Framework (SRF) is related to improving students' critical thinking ability in an argument-based inquiry approach, called the Science Writing Heuristic (SWH) approach. A total of 75 $8^{th}$ graders participated in the study, with 34 in the control group and 41 in the treatment group. The gains in critical thinking skills were compared between two groups, and relationships among the components of the reading framework and the critical thinking skills were explored at the group level. Result indicates that the treatment group who used the SRF had larger gains in critical thinking scores than control group who used the Original Reading Framework (ORF). In addition, results show that the correlations between Reading Framework (RF) components and critical thinking scores are statistically significant in the treatment group, while no correlations exist in the control group. It appears that using the SRF have an impact on developing students' critical thinking ability by providing a scaffold to assist argumentation practice.

• ETRI Journal
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• v.30 no.5
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• pp.747-749
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• 2008

We introduce a pixel-structured scintillator realized on a flexible polymeric substrate and demonstrate its feasibility as an X-ray converter when it is coupled to photosensitive elements. The sample was prepared by filling $Gd_2O_2S:Tb$ scintillation material into a square-pore-shape cavity array fabricated with polyethylene. For comparison, a sample with the conventional continuous geometry was also prepared. Although the pixelated geometry showed X-ray sensitivity of about 58% compared with the conventional geometry, the resolving power was improved by about 70% above a spatial frequency of 3 $mm^{-1}$. The spatial frequency at 10% of the modulation-transfer function was about 6 $mm^{-1}$.