• Title/Summary/Keyword: mathematical model development

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New Environmental Impact Assessment Technology (신환경영향평가기술(新環境影響評價技術)의 개발방향(開發方向))

  • Han, Sang-Wook;Lee, Jong-Ho;Nam, Young-Sook
    • Journal of Environmental Impact Assessment
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    • v.9 no.4
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    • pp.277-290
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    • 2000
  • The purpose of this study is to identify the problems of environmental impact assessment(EIA) and to suggest new EIA technology. The problems of EIA in Korea can be summarized as follows. First, the EIA does not reflect the impact of policy, plan and program on environment. Second, the project EIA does not consider the cumulative impacts such as additive impacts, synergistic impacts, threshold/saturation impacts, induced and indirect impacts, time-crowded impacts, and space-crowded impacts. Third, the EIA techniques in Korea are not standardized. Finally, the present EIA suggests only alternatives to reduce adverse impacts. To solve above-mentioned problems, the development of new EIA technology is essential. First, the new EIA technology should be developed toward pollution prevention technology and comprehensive and integrated environmental management technology. Second, new fields of EIA for pollution prevention contain strategic environmental assessment, cumulative impacts assessment, socio-economic impact assessment, cyber EIA and EIA technology necessary after the reunification of Korean Peninsula. Third, EIA technology for integrated environmental management contains the development of integated environment assessment system and the development of packaged EIA technology. The EIA technology for integrated environmental assessment system contains (1) development of integrated impact assessment technology combining air/water quality model, GIS and remote sensing, (2) integrated impact assessment of EIA, traffic impact assessment, population impact assessment and disaster impact assessment. (3) development of integrated technology combining risk assessment and EIA (4) development of integrated technology of life cycle assessment and EIA, (5) development of integrated technology of spatial planning and EIA, (6) EIA technology for biodiversity towards sustainable development, (7) mathematical model and GIS based location decision techniques, and (8) environmental monitoring and audit. Furthermore, there are some fields which need packaged EIA technology. In case of dam development, urban or industrial complex development, tourist development, landfill or combustion facilities construction, electric power plant development, development of port, road/rail/air port, is necessary the standardized and packaged EIA technology which considers the common characteristics of the same kind of development project.

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Stabilized marine and desert sands with deep mixing of cement and sodium bentonite

  • Saberian, Mohammad;Moradi, Mojtaba;Vali, Ramin;Li, Jie
    • Geomechanics and Engineering
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    • v.14 no.6
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    • pp.553-562
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    • 2018
  • Road construction is becoming increasingly important in marine and desert areas due to population growth and economic development. However, the load carrying capacity of pavement is of gear concern to design and geotechnical engineers because of the poor engineering properties of the soils in these areas. Therefore, stabilization of the soils is regarded as an important issue. Besides, due to the fuels combustion and carbonate decomposition, cement industry generates around 5% of global $CO_2$ emission. Thus, using bentonite as a natural pozzolan in soil stabilization is more eco-friendly than using cement. The aim of this research is to experimentally study of the stabilized marine and desert sands using deep mixing method by ordinary Portland cement and sodium bentonite. Different partial percentages of cement along with different weight percentages of sodium bentonite were added to the sands. Unconfined compression test (UCS), Energy Dispersive X-ray (EDX), and Scanning Electron Microscope (SEM) were conducted on the specimens. Moreover, a mathematical model was developed for predicting the strength of the treated soils.

Development & Test of A Small-Sized Autonomous Underwater Vehicle "BOTO" (소형 자율무인잠수정 "BOTO"의 개발 및 실험)

  • Byun, Seung-Woo
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.11
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    • pp.103-109
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    • 2012
  • Samsung Thales has developed a small-sized autonomous underwater vehicle "BOTO" verified by a mathematical model simulation. The hydrodynamic coefficients and drag force were experimented at circulating water channel for validating cruising performance of the AUV. Based on the mathematical model, we simulated turning radius and way-point tracking on horizontal plane using way-point tracking algorithm. In this paper we introduce the vehicle system and the sea trial test results will be shown.

A Frequency Analysis of the Control Input for Right Test (비행시험용 조종입력의 주파수분석)

  • Kwon Tae-Hee;Chang Jae-Won;Choi Sun-Woo;Seong Kie-Jeong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.1 s.20
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    • pp.39-48
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    • 2005
  • After the development of the Firefly, flight tests have been performed to verify the performance and get the parameters for the mathematical model of the aircraft. The flight test data is used to get parameters for the mathematical model of the aircraft through the parameter identification process. An arbitrary control input is applied to the test flight which is a part of parameter identification process. A square wave has been used a control input which is called Doublet signal. The aspect of the signal is same length and magnitude in both (+) and (-) directions such as sine wave. The Doublet signal is composed of a dominant frequency and many high frequencies, so that it is appropriate signal to excite the motion of an aircraft. In this paper, the control input of the flight test data has been analyzed to check the efficiency of the control input using DFT(Discrete Fourier Transform). From the result of analysis, an alternative input was extracted.

Multi-objective Optimization in Discrete Design Space using the Design of Experiment and the Mathematical Programming (실험계획법과 수리적방법을 이용한 이산설계 공간에서의 다목적 최적설계)

  • Lee, Dong-Woo;Baek, Seok-Heum;Lee, Kyoung-Young;Cho, Seok-Swoo;Joo, Won-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.10
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    • pp.2150-2158
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    • 2002
  • A recent research and development has the requirement for the optimization to shorten design time of modified or new product model and to obtain more precise engineering solution. General optimization problem must consider many conflicted objective functions simultaneously. Multi-objective optimization treats the multiple objective functions and constraints with design change. But, real engineering problem doesn't describe accurate constraint and objective function owing to the limit of representation. Therefore this study applies variance analysis on the basis of structure analysis and DOE to the vertical roller mill fur portland cement and proposed statistical design model to evaluate the effect of structural modification with design change by performing practical multi-objective optimization considering mass, stress and deflection.

Prototype Manufacturing Using 3D Printing and Characteristics of Flow Rate and Dynamics for High Temperature Solenoid Valve (3D 프린팅을 이용한 고온용 솔레노이드 밸브의 시제품 제작 및 유량과 동적특성 평가)

  • Yi, Hyung Wook;Lee, Yong Moon;Shin, Bo Sung;Lee, Tae Gu;Kang, Myung Chang
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.5
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    • pp.341-348
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    • 2016
  • The solenoid valve is used widely across various industries; however, solenoid valves for use in high-temperature environments have to be highly specified, such as those used in thermal power plants and steel mills. As such, we have developed a solenoid valve, using an already developed solenoid, to allow for more specific use. In this type of development method, use of 3D printing is very effective, allowing for a reduction in errors in design and production. This study includes a mathematical model of the solenoid valve. Then, the simulation from the mathematical model was performed using the AMESim (Advanced Modeling Environment for Simulation of Engineering Systems). We made a prototype valve using the simulation results and also measured the flow rate and dynamic performance.

A Survey of the cognition of Teachers, Students, Parents Towards Instructional Media in Mathematics Education (수학교육에서 교수매체에 대한 교사, 학생, 학부모의 인식 조사 연구)

  • 노선숙;김민경
    • The Mathematical Education
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    • v.40 no.2
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    • pp.265-289
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    • 2001
  • The elementary and middle school curriculum in Korea has been modified periodically to reach today's 7th national curriculum. Although the intent of each new curriculum was to improve education, lack of proper preparation for teachers and students has not made the new curriculums as effective as it could be. Goodlad et al.(1979) suggested that curriculum should encompass all practices including not only knowledge but all the elements of the curriculum and experiences of the student and teachers. The purpose of this paper is to investigate the actual practices of the current curriculum with focus on the use of instructional media in mathematics teaching and learning. A nationwide curriculum survey was carried out with the Goodlad's curriculum inquiry model as the framework. The result shows that elementary and secondary mathematics teachers used textbook manual (for teachers) and practice books most frequently for their class preparation. In addition to these, mathematics teachers also used manipulatives, visual aids, computers, internet, and calculators in a decreasing order. In general, many mathematics teachers did not use much instructional media in their classes and said that there are not enough effective instructional media to use. However, the teachers have positive attitude toward the educational media that they have used. In this study, we analyzed the survey data regarding educational tools, their use and effects to support the development of a new curriculum model in mathematics for a knowledge-based society.

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A study on the improvement of thickness accuracy in a plate mill

  • Lee, Duk-Man
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.723-727
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    • 2003
  • In this paper, two methods are discussed for good rolling force prediction in a plate mill. One is about the development of a long and a short learning scheme using a Neural Network for normal rolling and the other is about a mathematical model improvement by considering microstructural changes for controlled rolling. The research results are implemented in a on-line system of Pohang Works in POSCO and the field tests have showed that the prediction accuracies of rolling force are highly improved.

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Models for the Empty Container Repositioning and Leasing (공컨테이너 운영 관리를 위한 모형 개발)

  • 하원익;남기찬
    • Journal of the Korean Institute of Navigation
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    • v.23 no.2
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    • pp.11-22
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    • 1999
  • This paper is concerned with the development of a tractable model to assist liner shipping companies in the decision-making of empty container repositioning and leasing. A hybrid methodology is presented which properly accounts for the specific characteristics of empty container management. For this mathematical models are developed based on dynamic network models, covering both land and marine segment. Then a stochastic method is presented to deal with the uncertainty of the future demand and supply. Especially, the concept of opportunity cost has been introduced in order to explain interactions between the variation of the future demand and supply and the stock level at each depot.

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