• Title/Summary/Keyword: Rounding

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Studies on the Computerization of Reliability Paper (Ⅵ) (신뢰성 확률지의 전산화에 관한 연구 (Ⅵ))

  • 정수일
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.22 no.50
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    • pp.373-380
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    • 1999
  • This paper summerizes the former 5 papers that studied computer programming for the estimation of the Weibull, Extreme value, Hazard, Normal and Log-normal parameters which have a close relation with the reliability of the various kinds of industrial products. Probability paper is very commonly used in estimating the parameters, however, it is very hard to neglect the errors in plotting the data, and especially in drawing the regression line. The main purpose of this paper is to reduce these errors and to help the engineers to use the parameters in improving the reliability of their prod- ucts. The following parts are included in the computer programming with the em- phases on significant digits and rounding of numerical values : $\bullet$ data input part for various cases $\bullet$ parameter estimation part $\bullet$ printing part for input data $\bullet$ printing part for the results $\bullet$ printing part for the graphic(probability paper). And the running results(monitor displays) of the program for a fictitious example of Weibull distribution is given for the interested ones.

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A Study of the Safety Assessment for Combustion Products in the Exposure Human Bodies Rounding Missile Ejection (유도탄 사출시 연소 생성물의 인체 안전성 평가에 관한 연구)

  • Song, Kee Hyeok;Chung, Sung-Hak
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.37 no.4
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    • pp.269-273
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    • 2014
  • The objective of this study is to safety assessment for human body on the guided missile combustion products. This study is to verify the safety assessment when operating the interior missile ejection take on verify the safety of the human body. During the missile ejection of combustion products, this study is analyzed combustion products. Result are accepted NIOSH and KOSHA of the safe guideline, and 6 exposure gas to the specified values 42% (CO), 22% ($CO_2$), not detected (others) are within minimal exposures criteria of the reference value respectively. Contribution of these results supported that interior missile ejection during combustion products may have been ensured human safely. Therefore, the future for improving the environmental safety of the shooting projectile steel plate round, dust collector, ventilation and other facilities is to improve environmental safety and efficient renovated design needed by target focused areas.

Offsetting Operations in Non-manifold Geometric Modeling (비다양체 모델의 옵셋 기능 개발)

  • 이상헌
    • Korean Journal of Computational Design and Engineering
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    • v.3 no.1
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    • pp.1-14
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    • 1998
  • This paper introduces non-manifold offsetting operations, which add or remove a uniform thickness from a given non-manifold model. Since these operations can be applied to not only solids but also wireframe or sheet objects, they are potentially useful for pipeline modeling, sheet metal and plastic part modeling, tolerance analysis, clearance checking, constant-radius rounding and filleting of solids, converting of abstracted models to solids, HC too1 path generation and so on. This paper describes mathematical properties and algorithms for non-manifold offsetting. In this algorithm, a sufficient set of tentative faces are generated first by offsetting all or a subset of the vertices, edges and faces of the non-manifold model. And then they are merged into a model using the Boolean operations. Finally topological entities which are within offset distance are removed. The partially modified offsetting algorithms for wireframes or sheets are also discussed in order to provide more practical offset models.

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A Pyramid Data Structure for Progressive Lossless Image Transmission (무손실 점진적 영상 전송을 위한 피라미드 데이터 구조에 관한 연구)

  • 안재훈;정호열;최태영
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.6
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    • pp.49-58
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    • 1993
  • Extended reduced difference pyramid (ERDP) is proposed for lossless progressive image transmission, which is based on a new transform called rounded-transform(RT). The RT is a nonlinear and reversible transform of integers into integers utilizing two kinds of the rounding operations such as round up and down. The ERDP can be obtained from an N-poing RT or a series of RTs of both. For the performance evaluation, the entropy of the difference images to be transmitted is used as a lower bound transmission rate. Two examples of the ERDP can be easily shown, which is more effective in the entropy than the ordinary RDP.

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Tolerance-based Point Classification Algorithm for a Polygonal Region (공차를 고려한 다각형 영역의 내외부 판별 알고리즘)

  • 정연찬;박준철
    • Korean Journal of Computational Design and Engineering
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    • v.7 no.2
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    • pp.75-80
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    • 2002
  • This paper details a robust and efficient algorithm for point classification with respect to a polygon in 2D real number domain. The concept of tolerance makes this algorithm robust and consistent. It enables to define‘on-boundary’ , which can be interpreted as either‘in-’or‘out-’side region, and to manage rounding errors in floating point computation. Also the tolerance is used as a measure of reliability of point classifications. The proposed algorithm is based on a ray-intersection technique known as the most efficient, in which intersections between a ray originating from a given test point and the boundary of a region are counted. An odd number of intersections indicates that the point is inside region. For practical examples the algorithm is most efficient because most edges of the polygon region are processed by simple bit operations.

Registration of Multiple CT Images Using Principal Axis-based Rigid Body Transformation (주축기반 강체변환을 이용한 다중 CT 영상의 정합)

  • 유선국;김용욱;이혜연;김희중;김기덕;김남현
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.8
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    • pp.500-505
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    • 2003
  • In this paper, the method to register multiple sets of skull CT images to absolute coordinate system is proposed. Contrary to correspondence paired mapping of previous techniques, four anatomical landmark points, three coplanar points and one non-coplanar point, compose three principal axes simple and unique for efficient registration by means of rigid body transformation. Throughout the numerical simulation with added random noises, the error performances in terms of different rotation and rounding-off of landmark points, and incorrect localization of anatomical landmark and target points are quantitatively analyzed to generalize the proposed technique. Experiments using real skull CT images demonstrate the feasibility for an efficient use in clinical practice.

Image encryption through the chaos function and elementary row column operations (카오스 함수와 기본 행렬변환을 통한 영상의 암호화)

  • Kim, Tae-Sik
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.2
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    • pp.269-272
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    • 2005
  • For the efficient image encryption, we proposed the encryption algorithm using the chaotic function and elementary matrix operation defined on the bit plane decomposition. Though the chaotic encryption algorithm is faster than block encryption, it uses a real number computation. In this sense, we use the row and column operations on the bit-plane decomposed images combined with logistic function for the recursive rounding number, too.

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A Fixed-Point Error Analysis of fast DCT Algorithms (고정 소수점 연산에 의한 고속 DCT 알고리듬의 오차해석)

  • 연일동;이상욱
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.40 no.4
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    • pp.331-341
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    • 1991
  • The discrete cosine transform (DCT) is widely used in many signal processing areas, including image and speech data compression. In this paper, we investigate a fixed-point error analysis for fast DCT algorithms, namely, Lee [6], Hou [7] and Vetterli [8]. A statistical model for fixed-point error is analyzed to predict the output noise due to the fixed-point implementation. This paper deals with two's complement fixed-point data representation with truncation and rounding. For a comparison purpose, we also investigate the direct form DCT algorithm. We also propose a suitable scaling model for the fixed-point implementation to avoid an overflow occurring in the addition operation. Computer simulation results reveal that there is a close agreement between the theoretical and the experimental results. The result shows that Vetterli's algorithm is better than the other algorithms in terms of SNR.

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Influence of Sintering Parameters on the Mechanical Performance of PM Steels Pre-alloyed with Chromium

  • Bergman, Ola;Lindqvist, Bjorn;Bengtsson, Sven
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.280-281
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    • 2006
  • Powder grades pre-alloyed with 1.5-3 wt% chromium can be successfully sintered at the conventional temperature $1120^{\circ}C$ although well-monitored sintering atmospheres are required to avoid oxidation. Mechanical properties of the Cr-alloyed PM grades are enhanced by a higher sintering temperature in the range $1120-1250^{\circ}C$, due to positive effects from pore rounding, increased density and more effective oxide reduction. Astaloy CrM (Fe-3 wt% Cr-0.5 wt% Mo) with 0.6 wt% graphite added obtains an ultimate tensile strength of 1470 MPa and an impact strength of 31 J at density $7.1\;g/cm^3$, after sintering at $1250^{\circ}C$ followed by cooling at $2.5^{\circ}C/s$ and tempering.

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The MOSFET Hump Characteristics Occurring at STI Channel Edge (STI 채널 모서리에서 발생하는 MOSFET의 험프 특성)

  • 김현호;이천희
    • Journal of the Korea Society for Simulation
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    • v.11 no.1
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    • pp.23-30
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    • 2002
  • An STI(Shallow Trench Isolation) by using a CMP(Chemical Mechanical Polishing) process has been one of the key issues in the device isolation[1] In this paper we fabricated N, P-MOSFEET tall analyse hump characteristics in various rounding oxdation thickness(ex : Skip, 500, 800, 1000$\AA$). As a result we found that hump occurred at STI channel edge region by field oxide recess. and boron segregation(early turn on due to boron segregatiorn at channel edge). Therefore we improved that hump occurrence by increased oxidation thickness, and control field oxide recess( 20nm), wet oxidation etch time(19HF,30sec), STI nitride wet cleaning time(99HF, 60sec+P 90min) and fate pre-oxidation cleaning time (U10min+19HF, 60sec) to prevent hump occurring at STI channel edge.

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