• Title/Summary/Keyword: special values

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Effect of a chemical reaction on magnetohydrodynamic (MHD) stagnation point flow of Walters-B nanofluid with newtonian heat and mass conditions

  • Qayyum, Sajid;Hayat, Tasawar;Shehzad, Sabir A.;Alsaedi, Ahmed
    • Nuclear Engineering and Technology
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    • v.49 no.8
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    • pp.1636-1644
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    • 2017
  • The main purpose of this article is to describe the magnetohydrodynamic stagnation point flow of Walter-B nanofluid over a stretching sheet. The phenomena of heat and mass transfer are based on the involvement of thermal radiation and chemical reaction. Characteristics of Newtonian heating are given special attention. The Brownian motion and thermophoresis models are introduced in the temperature and concentration expressions. Appropriate variables are implemented for the transformation of partial differential frameworks into sets of ordinary differential equations. Plots for velocity, temperature, and nanoparticle concentration are displayed and analyzed for governing parameters. The skin friction coefficient and local Nusselt and Sherwood numbers are studied using numerical values. The temperature and heat transfer rate are enhanced within the frame of the thermal conjugate parameter.

A Development of Working Adaptation Evaluation System using Finger Force Measurement (지력측정을 이용한 작업 적합성 평가 시스템개발)

  • Byeon, M.K.;Hur, Woong;Han, S.C.;Kim, J.K.
    • Proceedings of the Safety Management and Science Conference
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    • 2002.05a
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    • pp.31-36
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    • 2002
  • In this paper, we developed a working adaptation evaluation system using finger force measurement which interact between material and biological system. The system consists of a finger force transducer, a signal conditioner, an A/D converter, a computer, and a software system for data processing. The finger force transducer is made by a load cell and a special mechanism. The data processing software controls the A/D converter, data monitoring, and data analysis for group classification. The developed system were tested by 4 different materials in left hand and the finger forte transducer in the other hand's thumb and index finger with 16 persons. As the results of experiments, the developed system could measure the finger force quantitatively and classify the measured values into four groups.

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Estimation of Parameters in a Variable Displacement Piston Pump (가변용량형 피스톤펌프의 파라미터 추정)

  • Huh J.Y.;Burton R.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.1 no.4
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    • pp.9-14
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    • 2004
  • An estimation technique called the Extended Kalman filter is used to estimate viscous friction, spring initial contraction, and the spring constant on the swash plate of a variable displacement pump. The feasibility of the approach was established using a simulation study. It showed that these parameters could be estimated very accurately in a reliable and independent fashion. A special experimental system was set up to facilitate the measurement of certain states to enhance the Kalman Filtering approach. The aforementioned parameters were estimated and found to be reasonably repeatable for a common operating point. It was very evident that as the operating conditions changed (i.e. temperature) so did the estimated values of certain parameters such as viscous friction. This was believed to be a good verification test for the approach.

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Software-based Real-time GNSS Signal Generation and Processing Using a Graphic Processing Unit (GPU)

  • Im, Sung-Hyuck;Jee, Gyu-In
    • Journal of Positioning, Navigation, and Timing
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    • v.3 no.3
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    • pp.99-105
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    • 2014
  • A graphic processing unit (GPU) can perform the same calculation on multiple data (SIMD: single instruction multiple data) using hundreds of to thousands of special purpose processors for graphic processing. Thus, high efficiency is expected when GPU is used for the generation and correlation of satellite navigation signals, which perform generation and processing by applying the same calculation procedure to tens of millions of discrete signal samples per second. In this study, the structure of a GPU-based GNSS simulator for the generation and processing of satellite navigation signals was designed, developed, and verified. To verify the developed satellite navigation signal generator, generated signals were applied to the OEM-V3 receiver of Novatel Inc., and the measured values were examined. To verify the satellite navigation signal processor, the performance was examined by collecting and processing actual GNSS intermediate frequency signals. The results of the verification indicated that satellite navigation signals could be generated and processed in real time using two GPUs.

A Study for Robustness of Objective Function and Constraints in Robust Design Optimization

  • Lee Tae-Won
    • Journal of Mechanical Science and Technology
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    • v.20 no.10
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    • pp.1662-1669
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    • 2006
  • Since randomness and uncertainties of design parameters are inherent, the robust design has gained an ever increasing importance in mechanical engineering. The robustness is assessed by the measure of performance variability around mean value, which is called as standard deviation. Hence, constraints in robust optimization problem can be approached as probability constraints in reliability based optimization. Then, the FOSM (first order second moment) method or the AFOSM (advanced first order second moment) method can be used to calculate the mean values and the standard deviations of functions describing constraints and object. Among two methods, AFOSM method has some advantage over FOSM method in evaluation of probability. Nevertheless, it is difficult to obtain the mean value and the standard deviation of objective function using AFOSM method, because it requires that the mean value of function is always positive. This paper presented a special technique to overcome this weakness of AFOSM method. The mean value and the standard deviation of objective function by the proposed method are reliable as shown in examples compared with results by FOSM method.

A Strategy for selectivity in research and development information: practical applications of the information analysis center concept (연구개발을 지원하는 정보 선별 전략 : 정보분석센터개념의 현실적 적용)

  • Koo Jayoung
    • Journal of the Korean Society for Library and Information Science
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    • v.13
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    • pp.143-181
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    • 1986
  • The present study aims at figuring out the potential benefits occured from the practical pplications of the information analysis center concept in Korea. The R&D requirements in Korea at the moment is such that the highly specialized and sophisticated information services are essential. With the general information infrastructure still embryonic the best possible answer is sought in a specialized tried-out method, namely, the information analysis center which is to be planned and serviced as an integral part of a specific research project. The article examines the information exchange activities of scientists; the backgrounds of the development of the information analysis center concept into 'a technical institute'; the processess of information analyses and evaluations; the effects and values of an analysis center; and the applicabilities of the information analysis center concept with a special regard to the developing country's needs. The conclusion confirms of the potential benefits of the information analysis center type facilities for the current needs of the Korean research and development environments.

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A study on the unit plan of smart silver town according to changeable life style (라이프스타일의 변화에 따른 스마트 실버타운 단위평면계획에 관한 연구)

  • Choi, Dong-Hoon;Jung, Chul-Oh;Kim, Yong-Seong
    • Proceedings of the Korean Institute of Interior Design Conference
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    • 2005.05a
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    • pp.79-82
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    • 2005
  • The development of industrial society brought about the highly-aged society, facilitated urbanization and nuclear families and changed conventional society and even the values. Also, development of Information Technology is represented digital technology makes general life-style of economy, society, culture and life. This paper offers there is sense to offer aged residing zero that equip amenities, safety, convenience considering enough request of aged by change of life-style. Hereupon, architecture enemy of aged residing, I wish to quote direction of unit planning of smart silver town that is intelligence style residing space that can correspond to various life-style that bring by information society by diagnosing change factor of residing space and internal and external study trend of smart groove that extract Needs of old age by change of special Quality and life-style and appears in digital environment.

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The Average Outgoing Quality of CSP's for Markov-Dependent Production Processes in Short Production Runs (마코프종속(從屬)인 생산공정의 운영기간(運營期間)에 따른 연속생산형(連續生産型) 샘플링 검사방식의 평균출검품질(平均出檢品質))

  • Park, Heung-Seon;Kim, Seong-In
    • Journal of Korean Institute of Industrial Engineers
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    • v.15 no.1
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    • pp.89-103
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    • 1989
  • In this paper the approximate average outgoing quality and properties of a class of continuous sampling plans in a short production run are investigated when the quality of successive units follows a two-state time-homogeneous Markov chain. The results of previous studies can be obtained as special cases. It is observed that the long-run average outgoing quality limit values under the statistical control differ significantly as compared to the case of short production runs in a Markov-dependent production process.

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A Study on Strength of Cement Mortar with Micro Grinding High Volume Fly-Ash (플라이애쉬를 다량 사용한 시멘트 경화체의 강도증진에 관한 실험적연구)

  • 정재동
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2001.11a
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    • pp.82-87
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    • 2001
  • The purpose of this study is for the active use of the fly ash, which is a by-product of the combustion pulverizes coal thermal power plants, to compensate for the lack of landfill and for conservation of energy, by using fly ash as the supplementary cementitious material, and to prove its possibility as the related products of the cement. First of all, the ordinary fly ash is grinded in a special method and its fineness is controlled from 6000$\textrm{cm}^2$/g to 8000$\textrm{cm}^2$/g, then replaced it with the 10% to 80% of the cement mortar in order to test physics characteristics. The first experiment conducts on the strength development in fly ash replacing content and fineness. and the changes of the flow values, incorporating fly ash into cement. The second one is about the slow development of the strength of the fly ash mortar in early ages, and improves its strength with the activator $Na_{2}SO_{4}$, using high volume fly ash.

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Development of Nano-Tungsten-Copper Powder and PM Processes

  • Lee, Seong;Noh, Joon-Woong;Kwon, Young-Sam;Chung, Seong-Taek;Johnson, John L.;Park, Seong-Jin;German, Randall M.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.377-378
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    • 2006
  • Thermal management technology is a critical element in all new chip generations, caused by a power multiplication combined with a size reduction. A heat sink, mounted on a base plate, requires the use of special materials possessing both high thermal conductivity (TC) and a coefficient of thermal expansion (CTE) that matches semiconductor materials as well as certain packaging ceramics. In this study, nano tungsten coated copper powder has been developed with a wide range of compositions, 90W-10Cu to 10W-90Cu. Powder technologies were used to make samples to evaluate density, TC, and CTE. Measured TC lies among theoretical values predicted by several existing models.

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