• 소성∙가공
• /
• 제10권3호
• /
• pp.185-192
• /
• 2001

In order to obtain the optimal products in deep drawing process, elliptical deep drawing tests were carried out with several shape radii of the punch and die. As parameters on testing, shape radii of the punch and die were selected. In addition, the conventional shape radii have been determined by trial-and-error using industrial experience and post processing test, and only approximate shape radii of the punch and die have been presented. The optimal shape radii of the punch and die in elliptical deep drawing process with biaxisymmetric blank shape are proposed. In this study, we suggest the appropriate conditions to be applicable to the actual manufacturing processes through the experiment and finite element method.

• East Asian mathematical journal
• /
• 제24권1호
• /
• pp.21-25
• /
• 2008

The semilocal convergence of the secant method under $H{\ddot{o}}lder$ continuous divided differences in a Banach space setting for solving nonlinear equations has been examined by us in [3]. The local convergence was recently examined in [4]. Motivated by optimization considerations and using the same hypotheses but more precise estimates than in [4] we provide a local convergence analysis with the following advantages: larger radius of convergence and finer error estimates on the distances involved. The results can be used for projection methods, to develop the cheapest possible mesh refinement strategies and to solve equations involving autonomous differential equations [1], [4], [7], [8].

• Journal of applied mathematics & informatics
• /
• 제8권3호
• /
• pp.743-753
• /
• 2001

We provide local convergence results in affine form for inexact Newton-like as well as quasi-Newton iterative methods in a Banach space setting. We use hypotheses on the second or on the first and mth Frechet-derivative (m≥2 an integer) of the operator involved. Our results allow a wider choice of starting points since our radius of convergence can be larger than the corresponding one given in earlier results using hypotheses on the first-Frechet-derivative only. A numerical example is provided to illustrate this fact. Our results apply when the method is, for example, a difference Newton-like or update-Newton method. Furthermore, our results have direct applications to the solution of autonomous differential equations.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.1117-1122
• /
• 2003

The paper on table deflection by stop state and move speed at loaded load, and the table deflection measured of static load. It is developed program for Date correction of LSM(Least Square Method). We experimented the method as following. The first a Laser setting and scan Experimental device measured curvature radius, The second A center of measurement object and curvature radius taking of LSC.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2000년도 춘계학술대회논문집
• /
• pp.92-95
• /
• 2000

In order to obtain the optimal products in deep drawing process elliptical deep drawing tests were carried out with several shape radii of the punch and die. As parameters on testing shape radii of the punch and die were selected, In addition the conventional shape radii have been determined by trial=and-error using industrial experience and post processing test and only approximate shape radii of the punch and die have been presented. The optimal shape radii of the punch and die in elliptical deep drawing process with biaxisymmetric blank shape are proposed. In this study we suggest the appropriate conditions to be applicable to the catual manufacturing processes through the experiment and finite element method.

• 천문학회보
• /
• 제41권1호
• /
• pp.42.2-42.2
• /
• 2016

It is well known that theoretical models of Wolf-Rayet stars are not consistent with observational data in terms of temperature and stellar radius. Recent study in analytical and numerical simulations show the importance of density inhomogeneity in stellar envelope. Using 1-dimensional numerical simulations, we study how such clumpiness arisen over convective surface of Wolf-Rayet stars affect their evolutionary path. Starting from pure helium star models, we constructed 21 different initial conditions by varying stellar mass, metallicity, and the clumpiness of the sub-surface convection zone. We run the simulations until the oxygen-burning is reached and find that the influence of the clumpiness is sensitive to the initial metallicity. Our models with high metallicity including the effect of the density inhomogeneity can roughly explain the observed properties of Wolf-Rayet stars such as stellar radius and temperature. By contrast, despite a considerable amount of density inhomogeneity is given, low metallicity models could not fully explain observations. To understand the inconsistency in low metallicity models, detailed study with improved model is required, taking account of the error range of the observations.

• 한국가시화정보학회지
• /
• 제17권2호
• /
• pp.83-89
• /
• 2019

In this study, we show the maximum cavity radius prediction model that a droplet impacts an inclined bath. Surface tensions, viscosities, inclination angles of a bottom substrate, droplet diameters, falling heights of the droplet are varied for the experiment. We experimentally observe that the cavity grows in hemispherical shape like the cavity formed in a deep bath although the depth of the bath is non-uniform due to an inclined bottom substrate. We derive two theoretical models to predict the experimental results of the fully developed cavity. Although each model has error, we observe that qualitatively theoretical model predicts the trend of experiment results well.

• 대한수학회보
• /
• 제56권3호
• /
• pp.621-629
• /
• 2019

In this paper, we present a local convergence analysis of a three point method with convergence order $1.839{\ldots}$ for approximating a locally unique solution of a nonlinear operator equation in setting of Banach spaces. Using weaker hypotheses than in earlier studies, we obtain: larger radius of convergence and more precise error estimates on the distances involved. Finally, numerical examples are used to show the advantages of the main results over earlier results.

• 제어로봇시스템학회논문지
• /
• 제15권7호
• /
• pp.734-741
• /
• 2009

A new localization algorithm is proposed for a fast moving mobile robot, which utilizes only one beacon and the global features of the differential-driving mobile robot. It takes a relatively long time to localize a mobile robot with active beacon sensors since the distance to the beacon is measured by the traveling time of the ultrasonic signal. When the mobile robot is moving slowly the measurement time does not yield a high error. At a higher mobile robot speed, however, the localization error becomes too large to locate the mobile robot. Therefore, in high-speed mobile robot operations, instead of using two or more active beacons for localization, only one active beacon and the global features of the mobile robot are used to localize the mobile robot in this research. The two global features are the radius and center of the rotational motion for the differential-driving mobile robot which generally describe motion of the mobile robot and are used for the trace prediction of the mobile robot. In high speed operations the localizer finds an intersection point of this predicted trace and a circle which is centered at the beacon and has the radius of the distance between the mobile robot and the beacon. This new approach resolves the large localization error caused by the high speed of the mobile robot. The performance of the new localization algorithm has been verified through the experiments with a high-speed mobile robot.

• 대한의용생체공학회:의공학회지
• /
• 제25권5호
• /
• pp.351-359
• /
• 2004

속도계측형 호흡기류센서는 베르누이 원리에 의해 기류속도를 동압력으로 변환하여 호흡기류를 측정하는 센서로써 다수의 샘플링 구멍을 기류통과면 상에 설치해야 한다. 본 연구에서는 속도 샘플 구명들을 비균등하게 배치시킴으로써 단순하게 균등 배치하는 것보다 훨씬 정확한 기류 계측이 가능함을 이론적으로 입증하였다 컴퓨터 시뮬레이션 결과 기류통과면을 다수의 등면적 링으로 분한하고 각각의 링의 면적을 다시 2등분하는 위치에서 속도를 샘플링함으로써 균등 배치할 경우에 비해 계측오차가 약 1/5로 감소하였다. 또한 충 샘플개수가 4개 이상이면 상대오차 1％ 이내의 매우 정확한 기류계측이 가능하였다. 기류 속도분포의 변화에 따른 영향을 비교한 결과 균등 샘플링에 비해 1/2 이하로 둔감하였다. 따라서 본 인구에서 제안하는 비균등 속도샘플링 기법은 속도 계측형 호흡기류센서의 설계시 매우 유용하게 적용될 것으로 판단된다.