• Title/Summary/Keyword: Cutting Model

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Cosmological Tests using Redshift Space Clustering in BOSS DR11

  • Song, Yong-Seon;Sabiu, Cristiano G.;Okumura, Teppei;Oh, Minji;Linder, Eric V.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.43.3-44
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    • 2015
  • We analyze the clustering of large scale structure in the Universe in a model independent method, accounting for anisotropic effects along and transverse to the line of sight. A large sample of 690,000 galaxies from The Baryon Oscillation Spectroscopy Survey Data Release 11 are used to determine the Hubble expansion H, angular distance D_A, and growth rate GT at an effective redshift of z=0.57. After careful bias and convergence studies of the effects from small scale clustering, we find that cutting transverse separations below 40 Mpc/h delivers robust results while smaller scale data leads to a bias due to unmodelled nonlinear and velocity effects. The converged results are in agreement with concordance LCDM cosmology, general relativity, and minimal neutrino mass, all within the $68{\backslash}%$ confidence level. We also present results separately for the northern and southern hemisphere sky, finding a slight tension in the growth rate -- potentially a signature of anisotropic stress, or just covariance with small scale velocities -- but within $68{\backslash}%$ CL.

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Economic Second-Order Modeling Using Modified Notz Design (수정된 Notz계획을 이용한 2차모형의 경제적 추정)

  • Yun, Tae-Hong;Byun, Jai-Hyun
    • Journal of Korean Society for Quality Management
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    • v.40 no.4
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    • pp.431-440
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    • 2012
  • Purpose: In this paper we propose modified Notz designs which are useful to experimenters who want to adopt the sequential experimentation strategy and to estimate second-order regression model with as few experimental points as possible. Methods: We first present the design matrices and design points in two or three dimensional spaces for such small sized second-order designs as small composite, hybrid, and Notz designs. Modified Notz designs are proposed and compared with some response surface designs in terms of the total number of experimental points, the estimation capability criteria such as D- and A-optimality. Results: When sequential experimentation is necessary, the modified Notz designs are recommendable. Conclusion: The result of this paper will be beneficial to experimenters who need to do experiments more efficiently, especially for those who want to reduce the time of experimentation as much as possible to develop cutting-edge products.

A study on the improvement of performance of polishing robot attached to machining center (머시닝센터 장착형 연마 로봇의 성능 향상에 관한 연구)

  • 조영길;이민철;전차수
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.1275-1278
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    • 1997
  • Cutting process has been automated by progress of CNC and CAD/CAM, but polishing process has been depended on only experiential knowledge of expert. To automate the polishing pricess polishing robot with 2 degrees of freedom which is attached to a machining center with 3 degrees of freedom has been developed. this automatic polishing robot is able to keep the polishing tool normal on the curved surface of die to improve a performance of polishing. Polishing task for a curved surface die demands repetitive operation and high precision, but conventional control algorithm can not cope with the problem of disturbance such as a change of load. In this research, we develop robust controller using real time sliding mode algorithm. To obtain gain parameters of sliding model control input, the signal compression method is used to identify polishing robot system. To obtain an effect of 5 degrees of freedom motion, 5 axes NC data for polishing are divided into data of two types for 3 axis machining center and 2 axis polishing are divided into data of two types for 3 axis machining center and 2 axis polishing robot. To find an efficient polishing condition to obtain high quality, various experiments are carried out.

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A Comprehensive Review of Emerging Computational Methods for Gene Identification

  • Yu, Ning;Yu, Zeng;Li, Bing;Gu, Feng;Pan, Yi
    • Journal of Information Processing Systems
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    • v.12 no.1
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    • pp.1-34
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    • 2016
  • Gene identification is at the center of genomic studies. Although the first phase of the Encyclopedia of DNA Elements (ENCODE) project has been claimed to be complete, the annotation of the functional elements is far from being so. Computational methods in gene identification continue to play important roles in this area and other relevant issues. So far, a lot of work has been performed on this area, and a plethora of computational methods and avenues have been developed. Many review papers have summarized these methods and other related work. However, most of them focus on the methodologies from a particular aspect or perspective. Different from these existing bodies of research, this paper aims to comprehensively summarize the mainstream computational methods in gene identification and tries to provide a short but concise technical reference for future studies. Moreover, this review sheds light on the emerging trends and cutting-edge techniques that are believed to be capable of leading the research on this field in the future.

External dose assessment for workers dismantling the bio-shield of a commercial power nuclear reactor: Case study of Kori-1, Korea

  • Lee, ChoongWie;Lee, Donghyun;Kim, Hee Reyoung;Lee, Seung Jun
    • Nuclear Engineering and Technology
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    • v.52 no.9
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    • pp.2085-2091
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    • 2020
  • The license for Kori-1, the first commercial reactor in Busan, Korea, was terminated in June 2017; therefore, preparations are being made for its decommissioning. Because the radioactivity of Bio-shield varies greatly throughout the structure, the doses received by the workers depend on the location, order, and duration of dismantling operations. Thus, a model for evaluating the worker external dose during the dismantling of the Kori-1 bio-shield was developed, and work scenarios for dose assessment were designed. The Dose evaluation code VISIPLAN was used for dose assessment. The dose rate around the bio-shield was evaluated and the level of exposure to the operator was evaluated according to the work scenario. The maximum annual external dose was calculated as 746.86 mSv for a diamond wire saw operator under dry cutting conditions, indicating that appropriate protective measures, such as changing dismantling sequence, remote monitoring, shield installation, and adjustment of work team are necessary for the safe dismantling of the bio-shield. Through these protective measures, it was found that the worker's dose could be below the dose limit.

A study of metal aspheric reflector manufacturing in diamond turning machine (다이아몬드 터닝머신을 이용한 금속 비구면 초정밀 절삭특성)

  • Kim, G.H.;Do, C.J.;Hong, K.H.;Rui, B.J.;Won, J.H.;Kim, S.S.
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.83-87
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    • 2001
  • A 110 mm diameter aspheric metal secondary mirror for a test model of an earth observation satellite camera was fabricated by ultra-precision single point diamond turning (SPDT). Aluminum alloy for mirror substrates is known to be easily machinable, but not polishable due to its ductility. A harder material, Ni, is usually electrolessly coated on an Al substrate to increase the surface hardness for optical polishing. Aspheric metal secondary mirror without a conventional polishing process, the surface roughness of Ra=10nm, and the form error of $Ra={\lambda}/12({\lambda}=632nm)$ has been required. The purpose of this research is to find the optimum machining conditions for reflector cutting of electroless-Ni coated Al alloy and apply the SPDT technique to the manufacturing of ultra precision optical components of metal aspheric reflector.

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Effect of the boundary shape of weld specimen on the stress distribution (용접시편의 테두리 모양이 응력 분포에 미치는 영향)

  • Yang, Seung-Yong;Goo, Byeong-Choon
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.348-352
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    • 2004
  • In finite element analysis of mechanical behavior of weld, typical process is first to obtain a finite element model containing residual stress by conducting welding analysis and then to examine the computational specimen for various external loading. The numerical specimen with residual stress has irregular boundary lines since one usually begins the welding analysis from a body having regular straight boundary lines and large thermal contraction takes place during cooling of weld metal. We notice that these numerical weld specimens are different from the real weld specimens as the real specimens are usually cut from a bigger weld part and consequently have straight boundaries neglecting elastic relaxation associated with the cutting. In this paper, an iterative finite element method is described to obtain a weld specimen which is bounded by straight lines. The stress distributions of two types of weld specimen, one with regular and the other with irregular boundaries, are compared to check the effect of the boundary shape. Results show that the stress distribution can be different when large plastic deformation is induced by the application of external loading. In case of elastic small deformation, the difference turns out almost negligible.

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The Study for Optimal Design of Spindle Insert used in Cotton Spinning Machine (방적기계용 스핀들 인서트의 최적설계 관한 연구)

  • Lee, Dong-Woo;Huh, Sun-Chul;Lee, Sang-Suk;Shim, Jae-Joon
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.4
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    • pp.72-78
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    • 2010
  • Textile machinery affects various industry, such as sport leisure industry, metal and chemistry material, electric electron, mechanical energy, packing and printing industry. In case of design of textile machine, the very important fact is absorbing the minute vibration induced by spinning thread and insert which is the part of spindle plays a role of reduction of impact caused by oscillation of thread bobbin. Therefore, Optimal design was executed by design of experiments and kriging optimal design methods to prevent fracture of spindle insert under the fatigue condition and deduced the best value of design parameter to improve the stability of the products. The highest sensitivity is showed at the design parameter A and D. As the spiral number of insert is increase, tension force applied its edge is distributed at whole model and the stress concentration is reduced.

A Study on the Magnetically Suspended Spindle with 16-pole Radial Magnets (16 극의 반경방향 전자석을 갖는 자기부상 주축계 연구)

  • Park, Jong-Kweon;Ro, Seung-Kook;Kyung, Jin-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.2
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    • pp.203-212
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    • 2002
  • Active magnetic hearings allow much high surface speed than conventional ball bearings and therefore greatly suitable for high speed cutting. This paper describes a design and test of an active magnetic bearing system with 16-pole radial magnets. The spindle is originally designed for a CNC lathe and driven by outer motor with 5.5 kW power and maximum speed 10,000 rpm. Considering static load condition and geometric restrictions, radial magnet is designed 16-pole type for smaller outer diameter of the spindle system. Dynamic system characteristics such as natural frequency, critical speed, stiffness, damping and system stabilities are simulated with a rigid rotor model including direct feedback controller. The designed spindle system is realized with digital PIDD controller to compensate phase lag of PWM amplifier and magnet coils. With levitation and step response experiment the control system characteristics are tested, and the spindle is rotated up to 10,000 rpm stab1y.

Analysis of Machined Surfaces by Ball-end Milling using the Ridge Method (능선 궤적법을 이용한 볼엔드밀 가공면 해석)

  • 정태성;남성호;박진호;양민양
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.1
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    • pp.51-60
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    • 2004
  • Ball-end milling is one of the most common manufacturing processes for the parts with sculptured surface. However, the conventional roughness model is not suitable for the evaluation of surface texture and roughness under highly efficient machining conditions. Therefore, a different approach is needed for the accurate evaluation of machined surface. In this study, a new method, named ‘Ridge method’, is proposed for the effective prediction of the geometrical roughness and the surface topology in ball-end milling. Theoretical analysis of a machined surface texture was performed considering the actual trochoidal trajectories of cutting edge. The characteristic lines of cut remainder are defined as three-types of ‘Ridges’ and their mathematical equations are derived from the surface generation mechanism of ball-end milling process. The predicted results are compared with the results of conventional method. The agreement between the results predicted by the proposed method and the values calculated by the simulation method shows that the analytic equations presented in this paper are useful for evaluating a geometrical surface roughness of ball -end milling process.