• 제목/요약/키워드: Difficulty value

검색결과 506건 처리시간 0.031초

종묘에서의 과학 현장 체험 학습 가능성 탐색 (Exploring Possibilities of Science Field Experience in Jongmyo Shrine)

  • 김진경;신동희
    • 한국초등과학교육학회지:초등과학교육
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    • 제33권2호
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    • pp.286-305
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    • 2014
  • We explored the possibilities of science field experience in Jongmyo Shrine in this study. To understand the educational value of self-leading science activities in Jongmyo Shrine, one of the World Heritage, we developed science program and applied it to the elementary students participating in a gifted education center. We collected and analyzed various data of opinionnaire survey before and after the program, field activity sheets, field observation, and individual- and group interview. The results showed the lack of students' spatial ability and proposed educational interests in science education. Also, a lot of students felt the difficulty in applying school science knowledge into the real life context. Students found the meaning of science learning through cooperative activities in the historically meaningful place. A proper use of smart device in science field experience was recommended. We found that activities with too much smart device might impede various scientific process skills.

Development of Neutrality System using Intelligent PLC

  • Ahn, Ihn-Seok;Kim, Sang-Bin;Ahn, Kwang-Seok;Lee, Sung-Hwan;Lee, Pyung-Gi
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.179.2-179
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    • 2001
  • This paper is about to consist of neutralization public decision system which is level controled the amount of inflow and outflow water to make use of PLC in automatic system and according to numerical value of PH, which is projected into a water tank counteragent automatically. But neverthless, appearance of extended PLC, there is a limit to realize from automatic system to intellectual system which is more efficient and active. There are two problems in PLC. First, there is not generalized that a module of PLC (which is installed in PLC) is realized control algorithm form. Second, there is a difficulty of expression that provided PLC control language is realized. There fore I take fuzzy inference control technique of various intellectual algorithm and 1 make a control rule and ...

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3차원 시뮬레이션 프로그램을 이용한 고층아파트의 개방감 측정에 관한 연구 (Estimating of High-rise Apartment Openness by 3D Simulation program)

  • 이우종;서정렬
    • Spatial Information Research
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    • 제7권1호
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    • pp.29-37
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    • 1999
  • 최근 주택을 선택함에 있어 주거환경에 대한 관심이 고조되고 있으며 이 가운데 강 또는 산 등 특정 대상으로의 조망과 개방감 여부가 주택가격을 결정짓는 중요한 요인으로 작용하고 있다. 실제로 기존 재고 주택시장의 아파트에 이러한 경관가치가 프리미엄의 형태로 주택가격에 내재되어 있는 것으로 나타났다. 따라서 신규 주택을 공급할 경우 특정 대상으로의 조망이나 개방감 여부를 판단할 수 있는 수단이 필요한 상황이다. 이에 본 연구에서는 3차원 시뮬레이션 프로그램(3D Studio Max)를 이용하여 개방감을 측정하는 방법을 모색하고자 하였다. 연구 결과 3차원 시뮬레이션 프로그램을 이용하여 개방감의 유무와 정도를 파악하는데 유용한 수단으로 이용될 수 있으며 이외의 다양한 목적으로도 활용될 수 있음을 제시하였다.

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종양의 진단과 치료가 가능한 오베트(OBET:O-Ring, Bioenergy Test)진단법 (OBET: O-Ring, Bioenergy Test for Diagnosis and Treatment of Tumors)

  • 황의현;한종현
    • 대한한방종양학회지
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    • 제6권1호
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    • pp.149-163
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    • 2000
  • The cells that make up the body continuously undergo cell division to maintain life, but stress and carcinogens, and physiological stimuli suppress immunological functions in the body and change cells to cancerous cells. The only way to overcome cancer is by treatment through early detection and proper diagnosis. However, because early stage of cancer shows subjective symptoms that are similar to those of other common illnesses, even doctors have difficulty separating cancer from common illnesses in its early stage. However, the Ki(bioenergy) present in our body recognizes and changes to the most minute changes in the body. This method of detecting the change in bioenergy to discover a disease in the early stage to raise treatment success is called the OBET: O-Ring, Bioenergy Test. This method, which is based on the theories of oriental medicine, focuses on tumors, especially malignant tumors, and has shown value in diagnosis and treatment, as witnessed in the clinical applications. The diagnosis method and cases of OBET: O-Ring, Bioenergy Test are presented.

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유한요소법에 의한 Bi2223 고온 초전도 선재의 다심 인발에 대한 연구 (A Study on Multi-Filament Drawing of Bi2223 High-Temperature Superconductivity Wire by FE Method)

  • 박동인;김병민;오상수
    • 소성∙가공
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    • 제13권1호
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    • pp.78-83
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    • 2004
  • High-temperature superconduction materials(Bi2223) possess electrical/electronic and magnetic properties. Because high-temperature superconduction materials is a ceramic powder, that cannot be produced singlehandedly. So Ag sheathed Bi-2223 wire was produced by drawing process using powder-in-tube(PIT) method. This superconductor has many difficulties to produce. The main difficulty is that the mechanical properties of the ceramic powder are very different from those of the Ag sheath. And by these properties, Bi2223 high-temperature superconductor, which has a single filament drawing process and multi-filament drawing process, has a defect like sausaging and bursting at a center. This study analyzed multi-filament drawing process by FEM, and a defect generated during multi-filament drawing was studied by FEH. Specially, in order to prevent a bursting at a center, this study presented a method that inserts a pure Ag at a center of multi-filament wire

Modeling and Evaluating Inventory Replenishment for Short Life-cycle Products

  • Wang, Ching-Ho;Lint, Shih-Wei;Chou, Shuo-Yan;Tsai, Chun-Hsiang
    • 대한산업공학회지
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    • 제34권4호
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    • pp.386-397
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    • 2008
  • Due to the rapid advancement of technologies, a growing number of innovative products with a short life-cycle have been introduced to the market. As the life-cycles of such products are shorter than those of durable goods, the demand variation during the life-cycle adds to the difficulty of inventory management. Traditional inventory planning models and techniques mostly deal with products that have long life-cycles. The assumptions on the demand pattern and subsequent solution approaches are generally, not suitable for dealing with products with short life-cycles. In this research, inventory replenishment problems based on the logistic demand model are formulated and solved to facilitate the management of products with short life-cycles. An extended Wagner- Whitin approach is used to determine the replenishment cycle, schedules and lot-sizes.

신경망에 의한 2 자유도 PID 제어기의 설계 (Design of 2-DOF PID control system by a Neural network)

  • 허진영;김홍렬;하홍곤;고태언
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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    • pp.262-266
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    • 1999
  • In this paper, we consider to apply of 2-DOF (Degree of Freedom) PID controller at D.C servo motor system. Many control system use I-PD, PID control system, but the position control system have difficulty in controling variable load and changing parameter. We propose neural network 2-DOF PID control system having feature for removal disturbrances and tracking function in the target value point. The back propagation algorithm of neural network used for tuning the 2-DOF parameter ($\alpha$, $\beta$, ${\gamma}$, η). We investigate the 2-DOF PID control system in the position control system and verify the effectiveness of proposal method through the result of computer simulation.

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HYBRID REORDERING STRATEGIES FOR ILU PRECONDITIONING OF INDEFINITE SPARSE MATRICES

  • Lee Eun-Joo;Zgang Jun
    • Journal of applied mathematics & informatics
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    • 제22권1_2호
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    • pp.307-316
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    • 2006
  • Incomplete LU factorization preconditioning techniques often have difficulty on indefinite sparse matrices. We present hybrid reordering strategies to deal with such matrices, which include new diagonal reorderings that are in conjunction with a symmetric nondecreasing degree algorithm. We first use the diagonal reorderings to efficiently search for entries of single element rows and columns and/or the maximum absolute value to be placed on the diagonal for computing a nonsymmetric permutation. To augment the effectiveness of the diagonal reorderings, a nondecreasing degree algorithm is applied to reduce the amount of fill-in during the ILU factorization. With the reordered matrices, we achieve a noticeable improvement in enhancing the stability of incomplete LU factorizations. Consequently, we reduce the convergence cost of the preconditioned Krylov subspace methods on solving the reordered indefinite matrices.

DC 서보모터 구동을 위한 신경망 2자유도 PID제어기 구성 (Construction Two Degree of freedom PID controller with Neural network for drives of DC servo motor)

  • 박광현;허진영;하홍곤
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2001년도 춘계종합학술대회
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    • pp.395-398
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    • 2001
  • 본 논문에서는 직류 서보 전동기를 구동원으로 하는 위치 제어계에서 부하변동에 따른 파라메타 변화, 외란 둥에 강인한 2자유도 PID 제어기의 설계법을 제시하여 신경망으로 2자유도 PID 제어기를 구성하였다. 이 제어기의 계수들이 기동시나 계 응답의 변동시 신경망 역전파 알고리즘(Back-Propagation Algorithm)에 의해서도 수성 되도록 하였다. 그리고 이것을 실제의 위치 제어계에 적용하여 실험을 통해 그 성능을 검증하였다.

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고차 등매개요소에서 내부절점의 위치와 해의 안정성 연구 (A study on the solution stability by the position of internal nodes in hihger order isoparametric elements)

  • 이준희;임장근
    • 대한기계학회논문집A
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    • 제21권12호
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    • pp.1973-1983
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    • 1997
  • Higher order isoparametric elements are usually used in the finite element analysis because they can represent easily the geometric shape of a complex structure ad can improve the solution quality. When these elements are used, the position of internal nodes affects greatly on the solution accuracy. Decreasing of the accuracy related to the position of internal nodes is due to non-conformal mapping often results in an unstable Jacobian value. This paper, in order to remove this difficulty, suggests a modified shape function which can establish conformal mapping between two coordinate systems. Numerical experiments with the proposed shape function show that a stable solution can be obtained without respect to the position of internal nodes, and offer convenience that one can take arbitrarily the position of internal nodes considering only the geometric shape of element boundaries.